OBJECTIVE. This article discusses how ribs are involved in a variety of traumatic, metabolic, inflammatory, neoplastic, and congenital disorders.
CONCLUSION. We review the normal anatomy pertinent to rib imaging and illustrate the key features of a variety of rib lesions, emphasizing the diagnostic value of CT.
OBJECTIVE. The purpose of this article is to show the imaging findings of variant types of hepatocellular carcinoma (HCC) with pathologic correlations.
CONCLUSION. The variant types of HCC may not share its typical imaging characteristics. An understanding of the radiologic findings for variant types of HCC can be helpful in the differential diagnosis of hepatic tumors.
OBJECTIVE. With recent advances in technology, advanced MRI methods such as diffusion-weighted and perfusion-weighted MRI, MR elastography, chemical shift-based fat-water separation, and MR spectroscopy can now be applied to liver imaging. We will review the respective roles of these techniques for assessment of chronic liver disease.
CONCLUSION. MRI plays an increasingly important role in assessment of patients with chronic liver disease because of the lack of ionizing radiation and the possibility of performing multiparametric imaging.
OBJECTIVE. This article aims to familiarize radiologists with novel treatment options for chronic heart failure that is unresponsive to medical therapy, such as mechanical cardiac assist devices, surgical procedures, resynchronization therapy with biventricular pacing, and cellular cardiomyoplasty, and their radiographic appearances.
CONCLUSION. Heart transplantation as a treatment of debilitating heart failure provides an opportunity for meaningful long-term survival but is limited by a shortage of donor hearts. This has spurred the development of new treatment options for chronic heart failure that is unresponsive to medical therapy.
OBJECTIVE. The purposes of this study were to use the myocardial delayed enhancement technique of cardiac MRI to investigate the frequency of unrecognized myocardial infarction (MI) in patients with end-stage renal disease, to compare the findings with those of ECG and SPECT, and to examine factors that may influence the utility of these methods in the detection of MI.
SUBJECTS AND METHODS. We prospectively performed cardiac MRI, ECG, and SPECT to detect unrecognized MI in 72 patients with end-stage renal disease at high risk of coronary artery disease but without a clinical history of MI.
RESULTS. Fifty-six patients (78%) were men (mean age, 56.2 ± 9.4 years) and 16 (22%) were women (mean age, 55.8 ± 11.4). The mean left ventricular mass index was 103.4 ± 27.3 g/m2, and the mean ejection fraction was 60.6% ± 15.5%. Myocardial delayed enhancement imaging depicted unrecognized MI in 18 patients (25%). ECG findings were abnormal in five patients (7%), and SPECT findings were abnormal in 19 patients (26%). ECG findings were false-negative in 14 cases and false-positive in one case. The accuracy, sensitivity, and specificity of ECG were 79.2%, 22.2%, and 98.1% (p = 0.002). SPECT findings were false-negative in six cases and false-positive in seven cases. The accuracy, sensitivity, and specificity of SPECT were 81.9%, 66.7%, and 87.0% (not significant). During a period of 4.9-77.9 months, 19 cardiac deaths were documented, but no statistical significance was found in survival analysis.
CONCLUSION. Cardiac MRI with myocardial delayed enhancement can depict unrecognized MI in patients with end-stage renal disease. ECG and SPECT had low sensitivity in detection of MI. Infarct size and left ventricular mass can influence the utility of these methods in the detection of MI.
OBJECTIVE. Rapid technical developments and an expanding list of applications that have supplanted less accurate or more invasive diagnostic tests have led to a dramatic increase in the use of body CT in medical practice since its introduction in 1975. Our purpose here is to discuss medical justification of the small potential risk associated with the ionizing radiation used in CT and to provide perspectives on practice-specific decisions that can maximize overall patient benefit. In addition, we review available dose management and optimization techniques.
CONCLUSION. Dose reduction strategies described in this article must be well understood and properly used, but also require broad-based practice strategies that extend beyond the CT scanner console and default, generic manufacturer settings. In the final analysis, physicians must request the imaging examination that best addresses the specific medical question without allowing worries about radiation to dissuade them or their patients from obtaining needed CT examinations. Ongoing efforts to ensure that CT examinations are both medically justified and optimally performed must continue, and education must be provided to the medical community and general public that put both the potential risks—and benefits—of CT examinations into proper perspective.
OBJECTIVE. The purpose of this cross-sectional study is to define the normal range of endplate angulation at T12 and L1 and, by doing so, to validate the angle measurement tools that are readily available on nearly all PACS.
MATERIALS AND METHODS. Two hundred consecutive lateral scout CT scans were examined in patients who were either 25 (n = 100) or 35 (n = 100) years old. The endplate angles for T12 and L1 were measured using a "Cobb angle" tool on a standard PACS workstation. Twenty-two cadaveric vertebrae were also imaged, and measurements obtained from the lateral scout CT image using electronic calipers were compared with measurements obtained with a goniometer.
RESULTS. The mean endplate angle at T12 measures 4.34° (2 SD, 4.5°) and at L1, 4.48° (4.26°). The normal range of endplate angulation is therefore -0.16° to 8.84° at T12 and 0.22-8.74° at L1. No statistically significant difference was seen in the endplate angulation when men were compared with women or 25- and 35-year-old age groups were compared. A strong correlation exists between direct and CT-derived endplate angle measurements.
CONCLUSION. Vertebral endplate angulation can be reliably measured using widely available PACS workstation tools. The mean endplate angle for T12 and L1 is approximately 4.5°, with an approximate range extending from 0° to 9°. For practical purposes, an endplate angle of 10° or more can be considered outside the normal range.
OBJECTIVE. The purpose of our study was to evaluate the clinical results of temporary stenting followed by radiation and/or chemotherapy in patients with inoperable malignant tracheobronchial strictures.
CONCLUSION. Temporary stenting combined with radiation therapy and/or chemotherapy may be clinically effective in the palliative treatment of patients with malignant tracheobronchial strictures. Stent placement may serve as an effective bridge to radiation and/or chemotherapy, allowing the latter to consolidate durable relief of obstructing symptoms by reducing tumor burden. Furthermore, our treatment strategy may increase patients' quality of life by reducing stent-related complications.
OBJECTIVE. The purpose of this article is to provide a timely update on a variety of key polyp topics to construct a proper framework for physicians who are interested in providing CT colonography screening as a clinical service.
CONCLUSION. As the medical community considers the expansion of CT colonography for screening, we believe it is prudent to update and review several key concepts regarding colorectal polyps. In particular, it is important to replace the older literature derived from high-risk and symptomatic cohorts with the wealth of newer and more applicable data from average-risk and asymptomatic screening cohorts. Familiarity with current concepts regarding flat (nonpolypoid) lesions and the natural history of small colorectal polyps is also vital to the effective application of this technique.
OBJECTIVE. The purpose of this study was to retrospectively evaluate the risk factors involved in the development of pneumothorax during radiofrequency ablation of lung tumors.
MATERIALS AND METHODS. This retrospective study covered 124 ablation sessions for lung tumors (10 primary lesions, 114 metastatic lesions) in 82 patients (46 men, 36 women; mean age, 64.0 years) treated between December 2005 and January 2008. The exclusion criteria for ablation therapy were lesions with a maximal diameter greater than 5 cm and the presence of more than five lesions. A bipolar electrode needle was used under CT guidance. Four patients were treated with two ablation electrodes simultaneously.
RESULTS. The incidence of pneumothorax (detected with CT) was 11.3% (14 of 124 sessions). Pneumothorax was graded mild (lung surface retraction, ≤ 2 cm), moderate (lung surface retraction, 2-4 cm), or severe (lung surface retraction, ≥ 4 cm). Significant risk factors encountered in the development of pneumothorax were age greater than 60 years (p = 0.046), emphysema (p = 0.02), tumor diameter ≤ 1.5 cm (p = 0.0008), lesions in lower part of lung, (p = 0.027), aerated lung parenchyma traversed by the needle track for a distance ≥ 2.6 cm (p = 0.0017), and traversal of a major pulmonary fissure (p = 0.0004). Pneumothorax developed in one of the four patients in whom multiple electrodes were used. The mean depth of lung lesions complicated by pneumothorax was 2.9 ± 1.55 cm (range, 0-5.5 cm). Conservative treatment was performed in four of the 14 pneumothorax sessions (28.6%). In six of the 14 sessions (42.9%), immediate complete evacuation was achieved with an intercostal catheter and manual evacuation; chest tube placement was indicated in four sessions (28.6%). Two patients were treated with manual evacuation because evidence of a progressive increase in pneumothorax on the 24-hour follow-up CT scan indicated failure of conservative treatment.
CONCLUSION. The development of pneumothorax complicating radiofrequency ablation can be unpredictable, but the many risk factors involved can make the incidence higher among some patients than others. Some of these risk factors are technically avoidable and have to be ruled out.
OBJECTIVE. The purpose of this article is to discuss the influence of tube potential on CT images and explore the potential impact of dual-energy CT on imaging of the abdomen and pelvis.
CONCLUSION. Low peak tube voltage (kVp) settings provide high conspicuity of contrast materials at CT but may result in high image noise, particularly in larger patients. Material decomposition at dual-energy CT can differentiate renal stones by their composition, quantify tissue iron stores, improve the detection of pathologic hyperenhancement, and reduce contrast material and radiation dose compared with conventional CT. Further clinical research and technique refinement will be needed as the usage of these exciting technologies spreads.
OBJECTIVE. Specific CT angiography (CTA) signs of vascular injury can be readily detected, and additional information regarding osseous and soft-tissue injuries can also be routinely obtained. In this article, we illustrate the important CTA signs of lower extremity vascular injury.
CONCLUSION. CTA is efficient and accurate in the evaluation of clinically significant lower extremity arterial injuries after trauma.
OBJECTIVE. Although ultrasound contrast agents (UCAs) are popular and widely used in Europe and Asia, the U.S. Food and Drug Administration (FDA) has not approved a microbubble agent for radiology imaging in the United States. Herein, we discuss the evidence for and the obstacles to using UCAs for contrast-enhanced ultrasound (CEUS).
CONCLUSION. Despite the obstacles to the use of UCAs for CEUS including regulatory and practice patterns, the evidence indicates that radiologists and patients will be missing an effectual imaging option if we do not encourage the use of CEUS and strongly support the approval of UCAs by the FDA. The evidence outweighs the obstacles: CEUS is cost-effective; can be performed at the bedside; uses no ionizing radiation; has no nephrotoxicity; and, most importantly, can provide accurate diagnostic information comparable to CT and MRI.
OBJECTIVE. The purpose of this study was to describe the clinical, imaging, and histopathologic findings of invasive micropapillary carcinoma of the breast.
CONCLUSION. The imaging characteristics of invasive micropapillary carcinoma are highly suggestive of malignancy. The lesion is a high-density irregular mass with indistinct margins associated with microcalcifications on mammograms; a solid irregular hypoechoic mass with indistinct margins and frequent axillary nodal involvement on sonograms; and a multifocal mass on MR images. This tumor may necessitate aggressive management.
OBJECTIVE. The objective of this article is to illustrate the spectrum of imaging findings with photographic and histopathologic correlation in patients with biopsy-proven nephrogenic systemic fibrosis (NSF).
CONCLUSION. Features of NSF may be evident on the patient's skin as well as on routine imaging studies, although these imaging findings are nonspecific and are more likely to occur with other diseases.
OBJECTIVE. The objective of our study was to present the imaging features, including an MRI example, of dermatofibrosarcoma protuberans of the breast, an uncommon soft-tissue neoplasm of the breast, and review the literature.
CONCLUSION. Dermatofibrosarcoma protuberans is an extremely rare malignancy of the breast, with few published reports. This is the largest collection of such cases in a single institution with analysis of the imaging features.
OBJECTIVE. The purpose of our study was to determine the sensitivity of CT colonography (CTC) interpreted by human readers and with computer-aided detection (CAD) for genuinely nonpolypoid colorectal lesions, defined as 2 mm or less in lesion height at colonoscopy.
MATERIALS AND METHODS. A computerized database search for a 33-month period found 21 patients who had undergone both colonoscopy and CTC and who had a total of 23 genuinely nonpolypoid colorectal lesions: eight adenomas (9-30 mm in width), 10 stage Tis or T1 adenocarcinomas (10-25 mm), and five nonadenomatous lesions (8-20 mm). CTC was performed using a cathartic preparation and fecal tagging and was interpreted by experienced readers in a blinded manner using a primary 3D method and with CAD.
RESULTS. The sensitivities of human readers for nonpolypoid adenomatous lesions (i.e., both adenomas and adenocarcinomas), adenocarcinomas, and nonadenomatous lesions were 66.7% (12/18), 90% (9/10), and 0% (0/5), respectively. Sensitivities were 55.6% (10/18), 90% (9/10), and 0% (0/5) for CAD. A 10-mm stage T1 adenocarcinoma was missed by a human reader on blinded review but was detected with CAD. Both human readers and CAD yielded significantly higher sensitivity for adenomatous lesions than for nonadenomatous lesions (p = 0.014 and 0.046, respectively) and for adenocarcinomas than for noncancerous lesions (p = 0.003 and 0.0001, respectively).
CONCLUSION. CTC showed a high sensitivity for nonpolypoid stage Tis and T1 adenocarcinomas 10 mm or greater in width despite the limited overall sensitivity for nonpolypoid adenomatous lesions, when performed using cathartic preparation and fecal tagging.
OBJECTIVE. We describe the case of a woman with a left breast mass. At mammography, the mass was shown to be irregular and accompanied by coarse calcification. Core needle biopsy revealed invasive carcinoma and a mastectomy was performed. Histopathology showed fibrosis with partial hyalinization eccentrically placed within the tumor with a large area of calcification at the core.
CONCLUSION. Benign calcifications within a breast mass are not diagnostic of a benign process if the imaging characteristics of the mass are suspicious.
OBJECTIVE. The objective of our study was to evaluate the feasibility of volumetric acquisition of the abdominal organs using performance guidelines that we developed in our preliminary experience.
MATERIALS AND METHODS. Mechanical volumetric acquisitions of each abdominal organ, including the liver, gallbladder, pancreas, kidneys, spleen, bowel, and aorta, were performed in 200 consecutive patients.
RESULTS. One thousand four hundred fifty-four volume data sets were graded for feasibility of performance and technical adequacy from I (impossible, incomplete) to V (excellent, complete). The most successfully imaged organ was the right kidney (grades IV and V, 95.0%) and the least successfully imaged, the spleen (grades IV and V, 69.0%). Very good to excellent grades (IV and V) were obtained in 1,215 (83.6%) of the 1,454 volumes. One hundred twelve (7.7%) of the 1,454 volumes were failures (grades I and II). The three organs with the highest success compared with the right kidney were the left kidney, gallbladder, and liver. The data sets of all the other organs showed a statistically significant difference in the feasibility of performance from the right kidney. Liver acquisition failures were associated with end-stage liver cirrhosis (n = 6), fatty liver (n = 3), and obesity (n = 3). Other acquisition failures, similar to conventional sonography, were associated with bowel gas interference and poor acoustic window. The technical limitations include poor resolution in the B and C planes and a limited range of frequencies; these limitations can be overcome in the future with matrix transducers and introduction of the technology to a broader frequency range.
CONCLUSION. Volumetric acquisition in the abdomen performed using defined guidelines is feasible with recognized limitations. Technology advances will improve this imaging technique in the future.
OBJECTIVE. The purpose of this study was to assess the efficacy and safety of contrast-enhanced ultrasound performed with perflubutane microbubbles in comparison with unenhanced ultrasound and dynamic CT in the characterization of focal liver lesions during the vascular phase of imaging and in the detection of lesions during the Kupffer phase.
SUBJECTS AND METHODS. A total of 196 patients were enrolled at 15 centers in Japan. Vascular phase images were obtained before contrast injection until 1 minute after injection. Kupffer phase images were obtained 10 minutes after injection. Dual-phase CT was performed as determined by standard clinical practice at each center. Unenhanced ultrasound, contrast-enhanced ultrasound, and CT images were read by blinded reviewers, and the results they reached regarding characterization and detection were compared with reference standard findings made by onsite investigators. The safety observation period was 72 hours after contrast administration.
RESULTS. Among the 190 patients included in the characterization analysis, the accuracy of contrast-enhanced ultrasound (88.9%) was significantly greater than that of unenhanced ultrasound (68.4%) and dynamic CT (80.5%) (p < 0.001 and p = 0.008). Among the 191 patients in the detection analysis, the efficacy of contrast-enhanced ultrasound in detection of lesions was significantly higher than that of unenhanced ultrasound and dynamic CT (p < 0.001 and p = 0.008), predominantly because more metastatic lesions were detected (both p < 0.001). In particular, contrast-enhanced ultrasound was superior to dynamic CT in the detection of metastatic lesions measuring 1 cm or smaller. The incidence of adverse events was 49.2% and that of adverse drug reactions was 10.4%. All adverse drug reactions were mild.
CONCLUSION. Compared with unenhanced ultrasound and dynamic CT, contrast-enhanced ultrasound with perflubutane microbubbles improved diagnostic efficacy in both characterization and detection of focal liver lesions with no serious adverse drug reactions.
OBJECTIVE. The purpose of this study was to compare low-dose unenhanced CT with standard-dose IV contrast-enhanced CT in the diagnosis of appendicitis.
MATERIALS AND METHODS. Two hundred seven adults with suspected appendicitis underwent CT with mean effective doses of both 4.2 and 8.0 mSv. Two radiologists retrospectively reviewed thin-section images by sliding a 5-mm-thick ray-sum slab. They rated the likelihood of appendicitis and appendiceal visualization on 5- and 3-point scales, respectively, and proposed alternative diagnoses. Likelihood ≥ 3 was considered a positive diagnosis. Receiver operating characteristics analysis, the McNemar test, and the Wilcoxon's signed-rank test were used.
RESULTS. Seventy-eight patients had appendicitis. The values of the area under the receiver operating characteristics curve were 0.98 for the low-dose unenhanced acquisition and 0.97 for the standard-dose contrast-enhanced acquisition for reader 1 (95% CI for the difference, -0.02 to 0.03) and 0.99 and 0.98 (-0.02 to 0.02) for reader 2. Sensitivity was 98.7% for low-dose unenhanced CT and 100% for standard-dose contrast-enhanced CT for reader 1 (p = 1.00) and 100% for both techniques for reader 2. Specificity was 95.3% and 93.0% (p = 0.25) and 96.9% and 96.9%. The interpretation was indeterminate (score 3) in 0.5% and 1.4% of cases for reader 1 (p = 0.63) and 0.5% and 0% for reader 2 (p = 1.00). A normal appendix was not visualized in 5.4% and 3.9% of cases by reader 1 (p = 0.63) and 3.9% and 2.3% of cases by reader 2 (p = 0.50). None of the patients whose appendix was not visualized had appendicitis. Diagnostic confidence, visualization score for a normal appendix, and correct alternative diagnosis tended to be compromised with use of low-dose unenhanced CT, showing a significant difference for a reader's confidence in the diagnosis of appendicitis (p = 0.004). The two techniques were comparable in the diagnosis of appendiceal perforation.
CONCLUSION. Low-dose unenhanced CT is potentially useful in the diagnosis of appendicitis.
OBJECTIVE. For this study, we aimed to selectively visualize the intrahepatic portal veins using 3D half-Fourier fast spin-echo (FSE) MR angiography (MRA) with a time-space labeling inversion pulse (T-SLIP) and to optimize the acquisition protocol.
SUBJECTS AND METHODS. Respiratory-triggered 3D half-Fourier FSE scans were obtained in 25 healthy adult subjects combined with two different T-SLIPs: one placed on the liver and the thorax to suppress signals of the liver parenchyma, hepatic veins, and abdominal arteries and the other on the lower abdomen to suppress the ascending signal of the inferior vena cava. One of the most important factors was the inversion time (TI) of the inversion pulse for the liver and thorax. Image quality was evaluated in terms of signal-to-noise ratio, contrast-to-noise ratio, and mean visualization scores at four different TIs: 800, 1,200, 1,600, and 2,000 milliseconds.
RESULTS. Selective visualization of the portal vein was successfully achieved in all volunteers, and anatomic variations were also seen in three subjects. A TI of 1,200 milliseconds was optimal in our protocol because it was sufficient for peripheral portal vein visualization and was most suitable for signal suppression of the hepatic veins and liver parenchyma.
CONCLUSION. Half-Fourier FSE scanning with T-SLIPs enabled selective visualization of the portal vein without an exogenous contrast agent.
OBJECTIVE. The objective of our study was to prospectively obtain pilot data on the accuracy of MR enterography for detecting small-bowel Crohn's disease compared with CT enterography and with a clinical reference standard based on imaging, clinical information, and ileocolonoscopy.
SUBJECTS AND METHODS. The study group for this blinded prospective study was composed of 33 patients with suspected active Crohn's ileal inflammation who were scheduled for clinical CT enterography and ileocolonoscopy and had consented to also undergo MR enterography. The MR enterography and CT enterography examinations were each interpreted by two radiologists with disagreements resolved by consensus. The reports from ileocolonoscopy with or without mucosal biopsy were interpreted by a gastroenterologist. The reference standard for the presence of small-bowel Crohn's disease was based on the final clinical diagnosis by the referring gastroenterologist after reviewing all of the available information.
RESULTS. All 33 patients underwent CT enterography and ileocolonoscopy, 30 of whom also underwent MR enterography. The sensitivities of MR enterography and CT enterography for detecting active small-bowel Crohn's disease were similar (90.5% vs 95.2%, respectively; p = 0.32). The image quality scores for MR enterography examinations were significantly lower than those for CT enterography (p = 0.005). MR enterography and CT enterography identified eight cases (24%) with a final diagnosis of active small-bowel inflammation in which the ileal mucosa appeared normal at ileocolonoscopy. Furthermore, enterography provided the only available imaging in three additional patients who did not have ileal intubation.
CONCLUSION. MR enterography and CT enterography have similar sensitivities for detecting active small-bowel inflammation, but image quality across the study cohort was better with CT. Cross-sectional enterography provides complementary information to ileocolonoscopy.
OBJECTIVE. Liver stiffness is associated with portal hypertension in patients with chronic liver disease. However, the relation between spleen stiffness and clinically significant portal hypertension remains unknown. The purposes of this study were to determine the feasibility of measuring spleen stiffness with MR elastography and to prospectively test the technique in healthy volunteers and in patients with compensated liver disease.
MATERIALS AND METHODS. Spleen stiffness was measured with MR elastography in 12 healthy volunteers (mean age, 37 years; range, 25-82 years) and 38 patients (mean age, 56 years; range, 36-60 years) with chronic liver disease of various causes. For patients with liver disease, laboratory findings, spleen size, presence and size of esophageal varices, and liver histologic results were recorded. Statistical analyses were performed to assess all measurements.
RESULTS. MR elastography of the spleen was successfully performed on all volunteers and patients. The mean spleen stiffness was significantly lower in the volunteers (mean, 3.6 ± 0.3 kPa) than in the patients with liver fibrosis (mean, 5.6 ± 5.0 kPa; range, 2.7-19.2 kPa; p < 0.001). In addition, a significant correlation was observed between liver stiffness and spleen stiffness for the entire cohort (r2 = 0.75; p < 0.001). Predictors of spleen stiffness were splenomegaly, spleen volume, and platelet count. A mean spleen stiffness of 10.5 kPa or greater was identified in all patients with esophageal varices.
CONCLUSION. MR elastography of the spleen is feasible and shows promise as a quantitative method for predicting the presence of esophageal varices in patients with advanced hepatic fibrosis.
OBJECTIVE. The purpose of this article is to describe the Doppler waveform findings in the hepatic artery in the early posttransplantation period, both in the absence and presence of arterial complications.
CONCLUSION. The presence of transient high-resistance Doppler waveforms in normal hepatic arteries is a common finding after grafting. Hepatic artery thrombosis and stenosis, and arterial steal syndromes can be diagnosed by Doppler in the early liver transplantation period.
OBJECTIVE. The purpose of this article is to present the typical and atypical manifestations of serous cystadenoma, which can be visualized with cross-sectional imaging.
CONCLUSION. Serous cystadenomas of the pancreas have various distinguishing imaging features. Typically, a serous cystadenoma is morphologically classified as having either a polycystic, honeycomb, or oligocystic pattern. Atypical manifestations of serous cystadenoma can include giant tumors with ductal dilatation, intratumoral hemorrhages, solid variants, unilocular cystic tumors, interval growth, and a disseminated form.
OBJECTIVE. The purpose of this study was to assess the feasibility and diagnostic value of dual-energy CT iodine mapping at pulmonary CT angiography.
SUBJECTS AND METHODS. Ninety-three patients underwent CT angiography with the dual-energy technique on a dual-source CT scanner. Postprocessing was used to map iodine in the lung parenchyma on the basis of its spectral behavior, and image quality was assessed by two readers. Iodine distribution patterns were rated as homogeneous, patchy, or circumscribed defects. Conventional CT angiographic images reconstructed from the same data sets were reviewed for the presence and localization of pulmonary embolism, whether embolic occlusion was partial or complete, and the presence of changes in the lung parenchyma. Dual-energy perfusion findings were correlated with the CT angiographic and lung-window CT findings in per-patient and per-segment analyses.
RESULTS. Iodine distribution was homogeneous in 49 patients, of whom CT angiography showed no pulmonary embolism in 46 patients and nonocclusive pulmonary emboli in three patients. Images of 29 patients showed a patchy pattern; 24 of these patients had no pulmonary embolism, and five had nonocclusive pulmonary emboli with solely nonocclusive intravascular clots. Images of 15 patients showed segmental or subsegmental defects; four of these patients had evidence of pulmonary embolism, and 11 had occlusive pulmonary emboli with at least one occlusive clot in the pulmonary vasculature.
CONCLUSION. Dual-energy CT is reliable in the detection of defects in pulmonary parenchymal iodine distribution that correspond to embolic vessel occlusion.
OBJECTIVE. The current standard-of-care workup of low-risk patients with chest pain in an emergency department takes 12-36 hours and is expensive. We hypothesized that negative 64-MDCT coronary angiography early in the workup of such patients may enable a shorter length of stay and reduce charges.
MATERIALS AND METHODS. The standard-of-care evaluation consisted of serial cardiac enzyme tests, ECGs, and stress testing. After informed consent, we added cardiac CT early in the standard-of-care workup of 53 consecutive patients. Fifty patients had negative CT findings and were included in this series. The length of stay and charges were analyzed using actual patient data for all patients in the standard-of-care workup and for two earlier discharge scenarios based on negative cardiac CT results: First, CT plus serial enzyme tests and ECGs during an observation period followed by discharge if all were negative; and second, CT plus one set of enzyme tests and one ECG followed by discharge if all were negative. Comparisons were made using paired Student's t tests.
RESULTS. For standard of care and the two CT-based earlier discharge analyses, the mean lengths of stay were 25.4, 14.3, and 5.0 hours; mean charges were $7,597, $6,153, and $4,251. Length of stay and charges were both significantly less (p < 0.001) for the two CT-based analyses.
CONCLUSION. In low-risk patients with chest pain, discharge from the emergency department based on negative cardiac CT, enzyme tests, and ECG may significantly decrease both length of stay and hospital charges compared with the standard of care.
OBJECTIVE. The Mammography Quality Standards Act of 1992 required a minimum performance audit of radiologists performing mammography. Since then, no studies have evaluated radiologists' perceptions of their audit reports, such as which performance measures are the most or least useful, or what the best formats are to present performance data.
MATERIALS AND METHODS. We conducted a qualitative study with focus groups and interviews of 25 radiologists currently practicing mammography. All radiologists practiced at one of three sites in the Breast Cancer Surveillance Consortium (BCSC). The discussion guide included open-ended questions to elicit opinions on the following subjects: the most useful performance outcome measures, examples of reports and formats that are easiest to understand (e.g., graphs or tables), thoughts about comparisons between individual-level and aggregate data, and ideas about additional performance measures they would find useful. All discussions were tape-recorded and transcribed. We developed a set of themes and used ethnographic software to qualitatively analyze and extract quotes from transcripts.
RESULTS. Radiologists thought that almost all performance measures were useful. They particularly liked seeing individual data presented in graphic form with a national benchmark or guideline for each performance measure clearly marked on the graph. They appreciated comparisons between their individual data and their peers' data (within their facility or state) and requested comparisons with national data (such as the BCSC). Many thought customizable, Web-based reports would be useful.
CONCLUSION. Radiologists think that most audit statistics are useful; however, presenting performance data graphically with clear benchmarks may make them easier to understand.
OBJECTIVE. Emphasis is being placed on improving the safety performance of the health care delivery system. The purpose of this study was to evaluate the effects of a program on safety performance and culture in a pediatric radiology department.
MATERIALS AND METHODS. A comprehensive safety program implemented in a department of radiology included error prevention training for all employees, a safety coach program, safety awards, Crucial Conversations training, and operational rounds with radiology leaders. The number of serious safety events (events with deviation from best practice, patient harm, and causation) that in part involved radiology were compared for 2 years after implementation of the program and the previous 2 years (baseline). A U.S. Agency for Healthcare Research and Quality safety culture survey was distributed to radiology employees, and the responses were compared for periods early in the program and after full implementation of the program. Fisher's exact test was used to evaluate for statistically significant differences (p < 0.05) in the survey responses and the frequency of serious safety events.
RESULTS. Before introduction of the safety program, radiology contributed to a serious safety event an average of once every 200 days as opposed to once in 780 days after implementation of the program (one event in more than two academic years) (p = 0.37). Improvement was found in all 12 dimensions of the culture survey after implementation of the program. Radiology scored higher than hospital averages in 10 of 12 dimensions of the survey.
CONCLUSION. The safety program had a positive effect on safety culture. Although it is early in the process and proving statistical significance for rare events such as serious safety events is difficult, the mean number of days between serious safety events has increased from 200 to 780. We conclude that the program is having a positive effect on safety performance.
OBJECTIVE. The purpose of our study was to show that sonography allows precise assessment of the location and course of the superficial peroneal nerve and of its relationship with other structures.
MATERIALS AND METHODS. This study, initially undertaken in cadavers, was followed by sonographic studies of 30 healthy adult volunteers (60 legs) by two radiologists in consensus. The location and course of the superficial peroneal nerve and its relationship with the adjacent anatomic structures were analyzed.
RESULTS. The entire course of the superficial peroneal nerve could be identified using sonography. The level at which the superficial peroneal nerve emerges between the peroneus longus and extensor digitorum longus muscles and the level at which it pierces the crural fascia and becomes subcutaneous were found to be highly variable. The superficial peroneal nerve was found to be located in the anterior compartment in 26.7% of the legs and to divide before piercing the crural fascia in 6.7% of the legs.
CONCLUSION. The superficial peroneal nerve can be clearly depicted by sonography. Knowledge of the nerve's precise location, which may show individual variations, may have useful clinical applications.
OBJECTIVE. The purpose of this study was to evaluate real-time sonoelastography in the assessment of the origins the common extensor tendon in healthy volunteers and in patients with symptoms of lateral epicondylitis. The findings were compared with those obtained at clinical examination, ultrasonography, and power Doppler sonography.
SUBJECTS AND METHODS. Thirty-eight elbows of 32 consecutively registered patients with symptoms of lateral epicondylitis and 44 asymptomatic elbows of 28 healthy volunteers were assessed with ultrasound and real-time sonoelastography. A clinical examination was performed, and pain was classified with a visual analog scale.
RESULTS. In healthy volunteers, real-time sonoelastographic images showed hard tendon structures in 96% of tendon thirds and mild alterations in 4%. Real-time sonoelastography of patients showed hard structures in 33% of tendon thirds but softening of different grades in 67%, a statistically significant difference in relation to the findings in healthy volunteers (p < 0.001). Lateral collateral ligament involvement and overlying fascial involvement were more commonly detected with real-time sonoelastography. The sensitivity of real-time sonoelastography was 100%, the specificity 89%, and the accuracy 94% with clinical examination as the reference standard. Good correlation with ultrasound findings was found (r ≥ 0.900). No correlation was observed between ultrasound or real-time sonoelastographic findings and power Doppler sonographic findings, but power Doppler sonographic findings had a strong correlation with the visual analog scale score.
CONCLUSION. Real-time sonoelastography is valuable in the detection of the intratendinous and peritendinous alterations of lateral epicondylitis and facilitates differentiation between healthy and symptomatic extensor tendon origins with excellent sensitivity and excellent correlation with ultrasound findings.
OBJECTIVE. The purpose of this study was to describe the MRI findings of an entity in which patients present with hip pain, abnormal MR signal intensity of the quadratus femoris muscle, and narrowing of the ischiofemoral space.
MATERIALS AND METHODS. We reviewed MR images of 12 hips in nine patients with hip pain and abnormal MR signal intensity of the quadratus femoris muscle. Using axial MR images, two musculoskeletal radiologists measured the ischiofemoral and quadratus femoris spaces. We also examined changes to muscles and tendons for the presence of edema and tears. Data were compared with 11 hips in 10 control subjects. Statistical analyses determined interobserver variability and differences between groups.
RESULTS. Subjects with an abnormal quadratus femoris muscle were all women 30-71 years old (mean age, 53 years) and had significantly narrower ischiofemoral spaces when compared with control subjects (13 ± 5 vs 23 ± 8 mm, respectively; p = 0.002). The quadratus femoris space was significantly narrower in affected subjects (7 ± 3 vs 12 ± 4 mm; p = 0.002). Abnormalities of the quadratus femoris muscle included edema (100%), partial tear (33%), and fatty infiltration (8%). The hamstring tendons of affected subjects showed evidence of edema (50%) and partial tears (25%).
CONCLUSION. Ischiofemoral impingement may represent a cause of hip pain and should be considered in cases with MR signal abnormality of quadratus femoris muscle.
OBJECTIVE. Toxic leukoencephalopathy may present acutely or subacutely with symmetrically reduced diffusion in the periventricular and supraventricular white matter, hereafter referred to as periventricular white matter. This entity may reverse both on imaging and clinically. However, a gathering together of the heterogeneous causes of this disorder as seen on MRI with diffusion-weighted imaging (DWI) and an analysis of their likelihood to reverse has not yet been performed. Our goals were to gather causes of acute or subacute toxic leukoencephalopathy that can present with reduced diffusion of periventricular white matter in order to promote recognition of this entity, to evaluate whether DWI with apparent diffusion coefficient (ADC) values can predict the extent of chronic FLAIR abnormality (imaging reversibility), and to evaluate whether DWI can predict the clinical outcome (clinical reversibility).
MATERIALS AND METHODS. Two neuroradiologists retrospectively reviewed the MRI examinations of 39 patients with acute symptoms and reduced diffusion of periventricular white matter. The reviewers then scored the extent of abnormality on DWI and FLAIR. ADC ratios of affected white matter versus the unaffected periventricular white matter were obtained. Each patient's clinical records were reviewed to determine the cause and clinical outcome. Histology findings were available in three patients. Correlations were calculated between the initial MRI markers and both the clinical course and the follow-up extent on FLAIR using Spearman's correlation coefficient.
RESULTS. Of the initial 39 patients, seven were excluded because of a nontoxic cause (hypoxic-ischemic encephalopathy [HIE] or congenital genetic disorders) or because of technical errors. In the remaining 32 patients, no correlation was noted between any of the initial MRI markers (percentage of ADC reduction, DWI extent, or FLAIR extent) with the clinical outcome. Three patients had histologic correlation. However, moderate correlation was seen between the extent of abnormality on initial FLAIR and the extent on follow-up FLAIR (r = 0.441, p = 0.047). Of the 13 patients who underwent repeat MRI at 21 days or longer, the reduced diffusion resolved in all but one. Significant differences were noted between ADC values in affected white matter versus unaffected periventricular white matter on initial (p < 0.0001) but not on follow-up MRI (p = 0.13), and in affected white matter on initial versus follow-up (p = 0.0014) in those individuals who underwent repeat imaging on the same magnet (n = 9), confirming resolution of the DWI abnormalities.
CONCLUSION. Acute toxic leukoencephalopathy with reduced diffusion may be clinically reversible and radiologically reversible on DWI, and may also be reversible, but to a lesser degree, on FLAIR MRI. None of the imaging markers measured in this study appears to correlate with clinical outcome, which underscores the necessity for prompt recognition of this entity. Alerting the clinician to this potentially reversible syndrome can facilitate treatment and removal of the offending agent in the early stages.
OBJECTIVE. The purpose of this study was to evaluate morphologic features predictive of benign thyroid nodules.
MATERIALS AND METHODS. From a registry of the records of 1,232 fine-needle aspiration biopsies performed jointly by the cytology and radiology departments at a single institution between 2005 and 2007, the cases of 650 patients were identified for whom both a pathology report and ultrasound images were available. From the alphabetized list generated, the first 500 nodules were reviewed. We analyzed the accuracy of individual sonographic features and of 10 discrete recognizable morphologic patterns in the prediction of benign histologic findings.
RESULTS. We found that grouping of thyroid nodules into reproducible patterns of morphology, or pattern recognition, rather than analysis of individual sonographic features, was extremely accurate in the identification of benign nodules. Four specific patterns were identified: spongiform configuration, cyst with colloid clot, giraffe pattern, and diffuse hyperechogenicity, which had a 100% specificity for benignity. In our series, identification of nodules with one of these four patterns could have obviated more than 60% of thyroid biopsies.
CONCLUSION. Recognition of specific morphologic patterns is an accurate method of identifying benign thyroid nodules that do not require cytologic evaluation. Use of this approach may substantially decrease the number of unnecessary biopsy procedures.
OBJECTIVE. It has been suggested that 18F-FDG uptake determined by PET can differentiate squamous cell carcinoma from benign sinonasal papilloma. We wish to present our experience with sinonasal papillomas and PET/CT to determine if the degree of FDG uptake is indicative of benign or malignant disease.
CONCLUSION. Benign sinonasal papilloma may be associated with intense FDG uptake on PET/CT. FDG PET/CT does not appear to reliably differentiate benign from malignant sinonasal papilloma.
OBJECTIVE. The objective of our study was to evaluate the effectiveness and safety of vesselplasty to treat symptomatic vertebral compression fractures (VCFs).
SUBJECTS AND METHODS. Twenty-nine patients undergoing vesselplasty at our institution between April 2006 and February 2008 were enrolled in the study. All patients had been undergoing medical therapy for one or more painful VCFs. Pain, mobility, and analgesic use scores were obtained, and restoration of vertebral body height was evaluated. A two-tailed paired Student's t test was used to compare differences in the mean scores for levels of pain, mobility, and analgesic use before and after the procedure and to evaluate changes in vertebral body height. We analyzed the influence of the age of the fracture and its cause in the variations in the pain, mobility, and analgesic use scores.
RESULTS. Seven of the 29 patients had fractures in more than one level, for a total of 37 procedures. The cause of the vertebral collapse was osteoporosis in 27 (73%), high-impact trauma in five (13.5%), myeloma in three (8%), and metastatic fracture in two (5.4%). The average pain score before treatment was 8.72 ± 1.25 (SD), whereas the average pain score after treatment was 3.38 ± 2.35. The average mobility score before treatment was 2.31 ± 1.94, whereas the average mobility score after treatment was 0.59 ± 1.05 (p < 0.001). The average analgesic use score before treatment was 3.07 ± 1.46, whereas it was 1.86 ± 1.90 after treatment (p < 0.001). There was no evidence of clinical complications.
CONCLUSION. Vesselplasty offers statistically significant benefits in improvements of pain, mobility, and the need for analgesia in patients with symptomatic VCFs, thus providing a safe alternative in the treatment of these fractures.
OBJECTIVE. The purpose of this study was to investigate the feasibility of prospective ECG-triggered axial 64-MDCT angiography of the aorta and coronary arteries performed at a tube voltage of 100 kV.
SUBJECTS AND METHODS. Thirty patients with a heart rate less than 75 beats/min who were referred for aortic CT angiography were enrolled. The image quality of the ascending aorta, aortic valve, and coronary arteries was evaluated for motion artifacts. Contrast enhancement (mean attenuation) was measured in the ascending aorta, descending aorta, and bifurcation of the aorta. Aortic valve and coronary artery lesions were surveyed.
RESULTS. Acceptable image quality was achieved in 100% (30/30) of cases for the ascending aorta, 97% (29/30) of cases for the aortic valve, and 98% (442/452) of coronary arterial segments. Contrast enhancement was greater than 200 HU and was satisfactory (ascending aorta, 379 ± 80 HU; descending aorta, 354 ± 72 HU; bifurcation, 355 ± 96 HU). Lesions found in the aortic valve were plaque (n = 16) and bicuspid valve (n = 1) and in the coronary arteries were ≥ 50% luminal stenosis (n = 5), plaque (n = 21), myocardial bridge (n = 12), and anomalous origin (n = 1). The effective radiation dose was estimated to be 7.5 ± 1.7 mSv.
CONCLUSION. For patients with a heart rate less than 75 beats/min, prospective ECG-triggered axial CT angiography at a tube voltage of 100 kV has the potential to provide clinically relevant information about the aorta and coronary arteries with low radiation exposure.
OBJECTIVE. The objective of our study was to evaluate the influence of endogenous and exogenous risk factors on the rate of nondiagnostic examinations of the calves in peripheral bolus-chase MR angiography (MRA).
SUBJECTS AND METHODS. Peripheral bolus-chase MRA runoff studies in 177 patients with peripheral arterial occlusive disease (PAOD) were retrospectively assessed with regard to the rate of nondiagnostic image quality due to substantial venous overlay in the calf arteries requiring repeated MRA examinations. Logistic regression was used to analyze the rate of nondiagnostic MRA examinations as a function of several endogenous and exogenous risk factors and of the stage of PAOD. To probe the retrospective data, 22 consecutive patients were prospectively included and underwent a standard peripheral MRA examination if the probability of a nondiagnostic examination was less than 50% based on the results of logistic regression; otherwise, a hybrid MRA examination was ordered.
RESULTS. Nondiagnostic image quality of the calf arteries was found in 53 patients (30%). The incidence increased with each stage of PAOD up to 39% for stage IV. For each increase in the stage of PAOD, the probability of nondiagnostic image quality increased by a factor of 1.5561 (p = 0.0024). With an increasing number of risk factors, a significantly (p = 0.0074) higher rate of nondiagnostic images was found.
CONCLUSION. Based on the retrospective statistical analysis of PAOD stages and risk factors, selected patients can be triaged to undergo a specific hybrid MRA technique and thus circumvent the occurrence of nondiagnostic images and the need for repeated MRA examinations.
OBJECTIVE. The objective of our study was to compare the clinical effectiveness of metallic stent placement for relief of gastric outlet obstruction caused by gastric carcinoma and pancreatic carcinoma.
MATERIALS AND METHODS. A total of 207 patients with gastric outlet obstruction caused by inoperable gastric carcinoma (n = 147) or pancreatic carcinoma (n = 60) underwent metallic stent placement.
RESULTS. Technical success of metallic stent placement was achieved in all patients. Clinical success was achieved in 97% and 93% of patients with gastric and pancreatic carcinoma, respectively (p = 0.286). The overall complication rate did not differ significantly between the gastric (29%) and pancreatic (23%) carcinoma groups (p = 0.441). Stent collapse was significantly more frequent in the gastric carcinoma group (11%) than the pancreatic carcinoma group (2%) (p = 0.027), whereas serious complications, including gastrointestinal bleeding and intestinal perforation, occurred more frequently in the pancreatic (7%) than the gastric (1%) carcinoma group (p = 0.026). The cumulative survival period was significantly longer in the gastric carcinoma (median, 153 days) than the pancreatic carcinoma (median, 90 days) group (p = 0.041), but cumulative stent patency did not differ significantly between the gastric carcinoma (median, 350 days) and pancreatic carcinoma (median, 385 days) groups (p = 0.415).
CONCLUSION. Metallic stent placement was clinically effective in the palliative treatment of gastric outlet obstruction in patients with gastric and pancreatic carcinoma. The two groups differed significantly in the rates of stent collapse and serious complications and patient survival after stent placement.
OBJECTIVE. The purpose of this study was to compare, focusing on colonic perforation and stent migration, the clinical safety and efficacy of dual-design expandable colorectal stents with flared ends with those of stents with bent ends in the treatment of patients with malignant colorectal obstruction.
SUBJECTS AND METHODS. A total of 122 patients with malignant colorectal obstruction underwent implantation of dual-design stents with flared (n = 69) or bent (n = 53) ends.
RESULTS. Stent placement was technically successful in 116 of 122 patients (95.1%), 65 of 69 patients (94.2%) with flared-end stents and 51 of 53 patients (96.2%) with bent-end stents (p > 0.05). Clinical success was achieved within 2 days in 61 of 65 patients (93.8%) with bent-end stents and in 46 of 51 patients (90.2%) with flared-end stents (p > 0.05). Complications included seven cases of colonic perforation (6%), seven cases of stent migration (6%), three cases of tumor overgrowth (2.6%), four cases of severe rectal pain (3.4%), and four cases of bleeding (3.4%). There were no significant differences between the rates of colonic perforation and stent migration in the two groups (6.2% vs 5.9%), and the overall complication rates were similar (p > 0.05).
CONCLUSION. Dual-design expandable colorectal stents with flared ends and those with bent ends are equally safe and effective, having similar perforation and migration rates.
