The "Wet Collar" Sign: A Case of Paraphimosis on CT.

Paraphimosis is a urologic emergency that requires prompt diagnosis to avoid potential morbidity. Diagnosis is made clinically and imaging findings have not been described. We will present the case of an 84-year-old man with a history of metastatic prostate cancer and prior pelvic external beam radiation therapy who presented to the emergency department with urinary retention. A urethral Foley catheter was placed for bladder decompression. He subsequently developed painful penile swelling and was found to have iatrogenic paraphimosis. Retrospective review of his contrast-enhanced CT of the abdomen and pelvis performed while in the emergency department before hospital admission revealed the relatively thickened, hypoattenuating prepuce located proximal to the corona of the glans penis, consistent with the clinical diagnosis. We will examine the imaging findings in this case and propose the novel "wet collar" sign to suggest the diagnosis of paraphimosis on CT.

Prospective evaluation of the prevalence of non-alcoholic fatty liver disease and steatohepatitis in a large middle-aged US cohort.

BACKGROUND & AIMS: Large prospective studies to establish the prevalence of non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH), are lacking. We prospectively assessed the prevalence and severity of NAFLD/NASH in a cohort of asymptomatic middle-aged Americans attending a colonoscopy class at a gastroenterology clinic. METHODS: Screening for NAFLD was performed using magnetic resonance (MR)-based LiverMultiScan® proton density fat fraction (LMS-PDFF). MR exams also included corrected T1 and elastography for liver stiffness measurement (LSM). FibroScan® was also used to measure LSM. Participants with predetermined abnormal imaging parameters were offered a liver biopsy. Biopsies were read in a blinded fashion with results based on the consensus by 2 expert pathologists. The prevalence of NAFLD was determined by PDFF ≥5% or by histological diagnosis of NAFLD (if biopsy data were available). The prevalence of NASH was defined by biopsy. RESULTS: Of 835 participants, 664 met the inclusion and exclusion criteria. The mean age was 56 ± 6.4 years, 50% were male, the mean BMI was 30.48 ± 5.46 kg/m2, and 52% were obese. The prevalence of NAFLD was 38% (95% CI 34-41%) and the prevalence of NASH was 14% (95% CI 12-17%). While no patient had cirrhosis on biopsy, significant fibrosis (F ≥2) was present in 5.9% (95% CI 4-8%) and bridging fibrosis in 1.6% (95% CI 1-3%). In a multivariable analysis, factors associated with the presence of NASH were race, obesity, and diabetes. CONCLUSION: Using state-of-the-art liver imaging modalities and reference biopsy, this study establishes an overall prevalence of NAFLD of 38% and NASH by biopsy of 14% in this cohort of asymptomatic middle-aged US adults. LAY SUMMARY: There are no prospective studies to determine how common is nonalcoholic steatohepatitis (NASH), the severe form of non-alcoholic fatty liver disease (NAFLD). In a large number of asymptomatic middle-aged Americans, we used a combination of state-of-the-art liver imaging methods and liver biopsy to prospectively determine the prevalence of NAFLD and NASH. NAFLD was diagnosed in 38%, NASH in 14%, and significant liver fibrosis in 6% of asymptomatic middle-aged Americans.

The double corpus luteum: A novel sonographic sign of heterotopic pregnancy.

Heterotopic pregnancy is a rare and highly morbid condition with simultaneous intrauterine and extra-uterine pregnancies. The early diagnosis of heterotopic pregnancy is difficult, owing to rarity of the condition and nonspecific clinical and laboratory findings. This case report introduces the "double corpus luteum" sign, a new sonographic and magnetic resonance imaging sign which is easily detectable and should raise the index of suspicion for heterotopic pregnancy. We present a surgically confirmed spontaneous heterotopic and angular pregnancy in a young woman without risk factors or assisted reproductive therapy to illustrate the utility of this novel sign.

Bilateral ovarian metastasis of clear-cell renal cell carcinoma: A case report.

Renal cell carcinoma (RCC) accounts for 2-3% of all adult malignancies. Clear-cell type RCC is the most common type, accounting for approximately 75% of all renal cancer cases. The most common sites of metastasis include the lung, bone, and liver. Ovarian metastasis of RCC is an exceptionally rare occurrence with only 41 cases reported in the literature with only 11 of these cases involving the bilateral ovaries. Here we present a case of clear-cell RCC arising from the left kidney with metastatic involvement of bilateral ovaries in a 48-year-old woman.

Technical success rate of MR elastography in a population without known liver disease.

PURPOSE: MR elastography (MRE) has a low technical failure rate in patients with chronic liver disease. The failure rate in an unscreened population is unknown. The purpose of this study was to determine the technical failure rate of MRE in patients with no known liver disease. METHODS: In this prospective trial, 633 patients received 673 scans on a 1.5 T MRI using a standard gradient recalled echo MRE protocol. Four MRE images were acquired and repeated as necessary. Two investigators in consensus categorized each failure: 1. Anatomical masking failure; 2. Iron deposition; 3. No waves (connection problem); 4. Poor wave propagation; 5. Poor passive driver placement; 6. Patient breathing problems. Full exam failure was defined as no usable data in all slices. Partial failure was no usable data on at least one slice. RESULTS: 1.0% (7/673) were full failures and 7.0% (47/673) were partial failures per patient. Full failures: iron deposition-71.4% (5/7); no waves-28.6% (2/7). 4.0% (108/2733) slice failure rate: Anatomical masking failure-31.5% (34/108); Iron deposition-25.0% (27/108); No waves-13.0% (14/108); Poor wave propagation-7.4% (8/108); Poor passive driver placement-11.1% (12/108); Patient breathing problems-12.0% (13/108). CONCLUSION: The failure rate of 1% is lower than for a screened population. Iron overload was implicated in most full failures. This study demonstrates the high technical success rate of MRE in an unscreened population laying the foundation for MRE as a possible screening tool for the general public.

The many faces of cirrhosis.

There are many different imaging features of cirrhosis, some of which are less commonly recognized. It is important that the radiologist is familiar with these features as cirrhosis can be first discovered on imaging performed for other indications, thus alerting the clinician for the need to screen for complications of cirrhosis and referral for potential treatment. This article reviews the various imaging findings of cirrhosis seen on cross-sectional imaging of the abdomen and pelvis.

Incidental Renal Lesions on Lumbar Spine MRI: Who Needs Follow-Up?

OBJECTIVE: Incidentally discovered renal lesions on lumbar spine MRI are a common occurrence. Many follow-up recommendations are generated by radiologists encountering renal lesions to help characterize the finding as a benign cyst or a more complex, potentially malignant lesion. We hypothesized that analysis of T2-weighted imaging features of incidentally discovered renal lesions could reliably distinguish complex renal lesions from simple cysts. MATERIALS AND METHODS: Two independent readers retrospectively evaluated 149 renal lesions identified on lumbar spine MRI examinations. Presence or absence of a complex renal lesion was determined using T2-weighted imaging only. Using dedicated renal cross-sectional imaging examinations as the reference standard, statistical analysis was performed to determine the accuracy of lumbar spine MRI in predicting a complex and potentially neoplastic renal lesion. RESULTS: Of 149 renal lesions, 115 were simple cysts, and 34 were complex renal lesions (20 Bosniak II cysts, nine renal cell carcinomas, three Bosniak IIF cysts, and two angiomyolipomas). Lumbar spine MRI readers identified 72 lesions as simple cysts and 77 lesions as complex renal lesions. Reader sensitivity for detection of a complex renal lesion on lumbar spine MRI was 94% (95% CI, 80-99%); specificity, 63% (95% CI, 53-72%); positive predictive value, 43% (95% CI, 37-49%); and negative predictive value, 97% (95% CI, 90-99%). Readers correctly identified all neoplastic and potentially neoplastic lesions (≥ Bosniak IIF). Interreader agreement was excellent (κ = 0.84). CONCLUSION: Follow-up imaging may not be required in all cases of incidentally discovered renal lesions on lumbar spine MRI. Analysis of T2-weighted imaging alone appears to reliably rule out neoplastic and potentially neoplastic complex renal lesions.

Postoperative CT of the Mandible Following Trauma: Review of Normal Appearances and Common Complications.

RATIONALE AND OBJECTIVES: Surgeons aim to restore occlusion and jaw function to baseline status for patients with mandibular fractures using either closed treatment or reduction and fixation. MATERIALS AND METHODS: Occlusion is defined as the relationship between the maxillary and mandibular teeth as they approach each other. RESULTS: Radiologists should be familiar with the goals of repair to help identify which treatment is adequate as well as to diagnose potential complications. Some of the more common complications encountered are infection, nonunion or malunion, and malocclusion. CONCLUSION: We provide a comprehensive review of both the desired and untoward CT findings after surgical repair of traumatic mandibular injuries.

Postoperative CT of the Midfacial Skeleton After Trauma: Review of Normal Appearances and Common Complications.

OBJECTIVE: The objective of this article is to describe the CT appearance of the midfacial skeleton after surgical repair of posttraumatic Le Fort, nasoorbitoethmoidal (NOE), and frontal sinus fractures. Several of the more commonly encountered complications will also be described. CONCLUSION: Surgery after midfacial trauma is aimed at restoring both form and function. Knowledge of the principal tenets of Le Fort, NOE, and frontal sinus fracture repair is vital for radiologists to accurately assess the adequacy of treatment on postoperative CT and provide meaningful reports for the surgeon.

Dual-energy Computed Tomography for the Evaluation of Enhancement of Pulmonary Nodules≤3 cm in Size.

PURPOSE: The aim of the study was to compare the accuracies of 4 different methods of assessing pulmonary nodule enhancement to distinguish benign from malignant solid pulmonary nodules using nondynamic contrast-enhanced dual-energy computed tomography. MATERIALS AND METHODS: Seventy-two patients (mean age, 62 y) underwent dual-energy chest computed tomography 3 minutes after intravenous contrast administration. Each of 118 pulmonary nodules (9±5.9 mm) were evaluated for enhancement by 4 methods: visual assessment, 3-dimensional automated postprocessing measurement tool, manually drawn region of interest with calculated iodine-related attenuation, and measurement of iodine concentration. The optimal cutoff for enhancement was defined as having the largest specificity among all cutoffs while maintaining 100% sensitivity. Accuracy of the methods was assessed with receiver operating characteristic curves. RESULTS: Ninety-three of 118 pulmonary nodules were benign (79%). Visual assessment of enhancement had sensitivity and specificity of 100% and 44%, respectively. For the automated 3-dimensional measurement tool, 20 HU was found to be the optimal threshold for defining enhancement, resulting in a specificity of 71% and a sensitivity of 100%, as well as an area under the curve (AUC) of 0.87 (95% confidence interval [CI], 0.82-0.92). The AUC was 0.79 (95% CI, 0.73-0.85) for the measured enhancement using a manually drawn region of interest. When a threshold of 21 HU was used for defining enhancement, maximum specificity was obtained (56%) while maintaining 100% sensitivity. The AUC for measured iodine concentration was 0.79 (95% CI, 0.77-0.85). At a cutoff iodine concentration of 0.6 mg/mL, the sensitivity was 100% with a specificity of 57%. CONCLUSIONS: Although use of automated postprocessing had the highest specificity while maintaining 100% sensitivity, there were only minor clinically relevant differences between measurement techniques given that no single technique misclassified a malignant nodule as nonenhancing.

Magnetic Resonance Imaging Characteristics of a Baerveldt Glaucoma Implant.

PURPOSE: Evaluate for normative postoperative magnetic resonance imaging (MRI) characteristics of a Baerveldt Glaucoma Implant (BGI). DESIGN: Prospective case series. PARTICIPANTS: Seven subjects with uncontrolled glaucoma requiring a primary superotemporal BGI. METHODS: Subjects prospectively underwent sequential MRI orbital scans without contrast at 0 to 2 weeks, 6 to 8 weeks, and 4 to 6 months after implantation of a BGI model 103-250. Masked to the postoperative time course, a radiologist measured bleb and implant characteristics. MAIN OUTCOME MEASURES: Linear measurements of the maximum bleb height at the anterior, middle, and posterior sections of the endplate were measured. Intraocular pressure (IOP) was correlated to bleb height. RESULTS: On axial T2-weighted images, the height of fluid below and above the BGI endplate increased from the initial to the final MRI images: 0.49 mm to 1.83 mm and 0.57 mm to 1.08 mm (middle 1/3), respectively. On coronal T2-weighted images, fluid below and above the BGI endplate increased from 0.47 mm to 1.53 mm and 0.49 mm to 1.38 mm, respectively. Maximum inverse correlation between bleb height and IOP was observed at the 6 to 8 week coronal T2 images (r=-0.963, P=0.002). CONCLUSIONS: Fluid collections and endplate characteristics are easily visualized with MRI. Dynamic changes occur over the early postoperative time course. Bleb height is inversely correlated to IOP at 6 to 8 weeks, but disappears at 4 to 6 months.

Mild asymptomatic intrahepatic biliary dilation after cholecystectomy, a common incidental variant.

OBJECTIVE: The purpose of this study is to evaluate the prevalence of intra- and extrahepatic ductal dilatation in asymptomatic individuals after cholecystectomy. METHODS AND MATERIALS: This IRB-approved retrospective cohort study evaluated the prevalence of intra- and extrahepatic biliary dilation in 77 consecutive post cholecystectomy patients who had CT obtained in the portal venous phase. These were then compared to age and sex matched control patients. Two radiologists in consensus blinded to surgical history evaluated the intrahepatic ducts qualitatively for dilatation. A single radiologist using the best of three orthogonal planes measured the extrahepatic ducts. Extrahepatic ducts were considered dilated if >7 mm plus 1 mm/decade after 60 years. T tests and chi-squared tests were performed. RESULTS: Cholecystectomy patient duct patterns: normal ducts 26% (20/77); intra- and extrahepatic dilation 31.2% (24/77); intrahepatic dilation only 18.2% (14/77); extrahepatic dilation only 24.7% (19/77). Control patient duct patterns: normal ducts 88.3% (68/77); intra- and extrahepatic dilation 2.6% (2/77); intrahepatic dilation only 2.6% (2/77); extrahepatic dilation only 6.5% (5/77). All intrahepatic ductal dilatation was mild. Total intrahepatic dilation: 49.4% (cholecystectomy); 5.2% (control patients). The relative risk of intrahepatic ductal dilation in cholecystectomy patients was 9.5:1. Increased prevalence of intra- and extrahepatic dilation in cholecystectomy patients was statistically significant (p < 0.0001). Average extrahepatic duct was 7.8 mm (cholecystectomy) and 5.3 mm (control patients) (p < 0.001). CONCLUSION: Mild intrahepatic biliary dilation in the setting of cholecystectomy is very common, and if not associated with clinical or biochemical evidence of obstruction is likely of no clinical significance.

Postoperative CT of the Orbital Skeleton After Trauma: Review of Normal Appearances and Common Complications.

OBJECTIVE: The purpose of this article is to describe both the expected and unexpected imaging features of posttraumatic defects of the orbital skeleton after surgical repair. CONCLUSION: The goal of surgery is to restore the preinjury orbital anatomy to improve function and prevent enophthalmos. Radiologists need to be cognizant of the more frequently encountered operative procedures used for orbital fracture repair, the desired goals of treatment, and common complications. This will permit accurate interpretation of postoperative CT and provide surgeons with clinically useful results.

Effect of Low-Osmolar Intravenous Contrast on Renal Length.

OBJECTIVE: The purpose was to study the effect of low-osmolar nonionic contrast on renal length. MATERIAL AND METHODS: This study included 56 patients (4-phase renal computed tomography [CT] and 4-phase CT urogram [CTU], 19 patients each; split-phase CTU, 18 patients). Three radiologists created the best off-axis plane and renal lengths measured on a postprocessing workstation. Two-way analysis of variance with Bonferroni corrections was performed along with single-sample t tests. RESULTS: Four-phase renal CT and CTU average differences from unenhanced phases were 0.30/0.16 mm (corticomedullary), 0.88/1.33 mm (nephrographic), and 2.17/2.22 mm (delayed). The nephrographic and delayed phases were significantly different from their unenhanced phase (P < 0.01). Nonsignificant differences between the corticomedullary phase and the unenhanced phase were observed (P = 0.217, 4-phase renal CT; P = 0.232, 4-phase CTU). The split-phase CTU average difference in the enhanced phase was 1.36 mm (P < 0.001). CONCLUSION: Renal length increases 1 to 2 mm with low-osmolar nonionic contrast.

Multiplanar Reformations in the Measurement of Renal Length on CT: Is It Plain Which Plane to Use?

OBJECTIVE: The objective of this study was to determine the accuracy of renal measurement on CT in multiple imaging planes. MATERIALS AND METHODS: In this study, three board-certified radiologists retrospectively measured 110 kidneys on CT in 55 consecutive patients. Five measurement methods were used: axial, coronal single image, coronal multiimage, sagittal single image, and sagittal multiimage. The coronal database was sent to a postprocessing workstation, and each radiologist performed a maximum renal measurement using a best off-axis plane that was our reference standard. An ANOVA test with repeated measures and posthoc Bonferroni corrected t tests were performed. RESULTS: The mean differences (± standard error) compared with the reference standard method were as follows: axial, 7.7 ± 0.7 mm; coronal single image, 13.1 ± 1.4 mm; coronal multiimage, 6.4 ± 0.8 mm; sagittal single image, 6.4 ± 0.6 mm; and sagittal multiimage, 2.8 ± 0.3 mm. The reference standard measurement was larger (p < 0.001), whereas the coronal single-image measurement (p ≤ 0.006) was smaller than all other methods. The sagittal multiimage (p ≤ 0.005) was statistically significantly different from all other methods. There were no statistically significant differences among the axial, coronal multiimage, and sagittal single-image methods (p ≥ 0.088). CONCLUSION: The single-image coronal method is the least accurate, with an error of approximately 13 mm. The axial, multiimage coronal, and single-image sagittal methods underestimate renal size by approximately 6-8 mm. Multiimage sagittal is the most accurate method for measuring kidneys with an error of approximately 3 mm.

Review of Commonly Used Serum Tumor Markers and Their Relevance for Image Interpretation.

Serum tumor markers are firmly entrenched as one of the primary tools in an oncologist's armamentarium. They can be implemented in a broad range of applications from diagnostic assistance, assessing prognosis, or guiding therapeutic decisions. However, tumor markers also have limitations, which significantly impact how they should be used. Radiologists should be familiar with the following most prevalent tumor markers, which will all be discussed here: prostate-specific antigen (prostate), carcinoembryonic antigen (colon), α-fetoprotein (hepatocellular and testicular), carbohydrate antigen 19.9 (pancreas), cancer antigen 125 (ovarian), human chorionic gonadotropin/lactic dehydrogenase (testicular), and chromogranin A (neuroendocrine). This knowledge should avoid needless intervention, enhance image interpretation, and ultimately provide optimal patient care.

Can a T2 hyperintense rim sign differentiate uterine leiomyomas from other solid adnexal masses?

PURPOSE: To investigate the incidence of high T2 signal rims surrounding leiomyomas, evaluate if a particular T2-weighted sequence is more effective in depicting this rim, and determine if this sign is useful in differentiating pedunculated leiomyomas from other solid adnexal masses. MATERIALS AND METHODS: In this retrospective study, two radiologists evaluated 233 T2 dark pelvic masses (223 uterine leiomyomas and 10 ovarian fibromas) in 60 women (mean age 47) on Magnetic resonance imaging for the presence of a high signal rim. Three different T2-weighted sequences were reviewed independently for uterine leiomyomas: half-Fourier acquisition single-shot turbo spin echo (HASTE), SPACE, and T2 with fat saturation (T2 FS). Only T2 FS images were available for 10 fibromas. A consensus review was conducted for discrepant cases. Statistical analyses were performed using Fisher's exact test, kappa test, and ANOVA RESULTS: For 223 uterine leiomyomas, 23% (95% CI 17.8-28.9%) demonstrated a high T2 signal rim sign on T2 FS compared with 4.9% (95% CI 2.6-8.9%) for HASTE and 6.7% (95% CI 3.9-11.1%) for SPACE. The difference between the number of positive rims on T2 FS relative-HASTE and SPACE was statistically significant (p < 0.001). For ovarian fibromas, 40% (95% CI 16.9-68.8%) were classified positive for a rim sign. CONCLUSION: A high T2 signal rim sign was present for up to 23% of uterine leiomyomas and the T2 FS sequence detected this rim sign most frequently. Up to 40% of ovarian fibromas can also have a T2 rim sign and, therefore, a solid adnexal mass with a T2 rim sign cannot be assumed to represent a pedunculated leiomyoma.

Role of imaging for patients with colorectal hepatic metastases: what the radiologist needs to know.

Surgical resection of colorectal metastatic disease has increased as surgeons have adopted a more aggressive ideology. Current exclusion criteria are patients for whom a negative resection margin is not feasible or a future liver remnant (FLR) of greater than 20% is not achievable. The goal of preoperative imaging is to identify the number and distribution of liver metastases, in addition to establishing their relation to relevant intrahepatic structures. FLR can be calculated utilizing cross-sectional imaging to select out patients at risk for hepatic dysfunction after resection. MRI, specifically with gadoxetic acid contrast, is currently the preferred modality for assessment of hepatic involvement for patients with newly diagnosed colorectal cancer, to include those who have undergone neoadjuvant chemotherapy. Employment of liver-directed therapies has recently expanded and they may provide an alternative to hepatectomy in order to obtain locoregional control in poor surgical candidates or convert patients with initially unresectable disease into surgical candidates.

Postoperative imaging of the orbital contents.

Ophthalmologists perform a wide array of interventions on the orbital contents. The surgical treatment of glaucoma, cataracts, retinal detachment, and ocular trauma or malignancy results in alteration of the standard anatomy, which is often readily evident at radiologic examinations. The ability to accurately recognize the various imaging manifestations after orbital surgery is critical for radiologists to avoid misdiagnosis. Of particular importance is familiarity with the numerous types of implanted devices, such as glaucoma drainage devices, orbital implants, and eyelid weights. Although knowledge of patients' surgical history is helpful, this information is often not available at the time of interpretation. Fortunately, there are characteristic posttreatment findings that enable diagnosis. The imaging features of the most commonly performed ophthalmologic procedures are highlighted, with emphasis on computed tomography and magnetic resonance (MR) imaging, because they are currently the primary modalities involved in evaluating the orbits. Glaucoma drainage devices and orbital implants after enucleation are two of the more pertinent implanted devices because their composition has substantially evolved over the past 2 decades, which affects their imaging appearance. Some devices, such as the Baerveldt Glaucoma Implant and platinum-weighted eyelid implants, may distort radiologic images. The MR imaging safety profiles of numerous implanted devices are also reported.