Description: Purpose The purpose of this study is to evaluate qualitative and quantitative analysis of contrast-enhanced ultrasound (CEUS) in differential diagnoses of hypo-echoic renal tumor histotypes. Methods Our study cohort comprised 103 clear cell renal cell carcinomas (ccRCCs), 24 papillary renal cell carcinomas (pRCCs), 28 chromophobe renal cell carcinomas (cRCCs), and 34 angiomyolipomas (AMLs), hypo-echoic on ultrasound, and imaged between January 2011 and December 2013. Enhancement homogeneity and tumor-to-cortex intensity ratio (TOC ratio) were retrospectively analyzed. Results Overall, heterogeneous enhancement was more common in ccRCCs than AMLs, pRCCs, and cRCCs. TOC ratio showed the trend ccRCC 〉 AML 〉 pRCC = cRCC. Similar trends were seen in tumors 〈4 cm. Using heterogeneous enhancement or TOC ratio 〉107.5% to differentiate ccRCC from other histotypes, the sensitivity, specificity, positive and negative predictive values were 93.1%, 74.5%, 84.8%, and 87.5%, respectively. Tumors 〉4 cm exhibited considerable overlap in enhancement homogeneity among different histotypes. TOC ratios were similar between homo- and heterogeneously enhancing tumors for ccRCCs and for pRCCs and cRCCs, but higher in homogeneously enhancing than heterogeneously enhancing AMLs. In homo- and heterogeneously enhancing tumors, TOC ratios followed the trends ccRCCs 〉 AMLs 〉 pRCCs = cRCCs and ccRCCs 〉 AMLs = pRCCs = cRCCs, respectively. With TOC ratio 〉105.81% and 〉72.37% to differentiate homo- and heterogeneously enhancing ccRCCs from other histotypes in tumors 〉4 cm with same enhancement homogeneity, the sensitivity, specificity, positive and negative predictive values were 70.0%, 85.7%, 70.0%, 85.7%, and 91.7%, 94.4%, 95.7%, 89.5%, respectively. Conclusion CEUS homogeneity and TOC ratio are helpful in differential diagnosis of hypo-echoic renal tumor histotypes. Diameter and enhancement homogeneity should be considered when deciding the diagnostic TOC ratio cutoff.

Description: Small bowel transplantation is a surgical technique reserved for patients with end-stage intestinal failure. Despite its inherent technical difficulties, it has emerged as the standard of care for these patients. This article reviews the background and different surgical techniques for this procedure and then fully describes the spectrum of imaging findings of pancreatic and biliary complications, which have a prevalence of up to 17%, after this procedure based on 23-year single-center experience. The pancreaticobiliary complications encountered in our experience and discussed in this article include: ampullary stenosis, biliary cast, choledocholithiasis, bile leak, recurrent cholangitis, acute pancreatitis, chronic pancreatitis, and pancreatic duct fistula. Familiarity with the broad spectrum of PB complications and their variable manifestations will help radiologists to accurately diagnose these complications which have relatively high morbidity and mortality in these immune-compromised patients.

Description: Purpose To develop a preoperative CT-based nomogram for predicting overall survival (OS) in patients with non-endometrioid carcinomas of the uterine corpus. Methods Waiving informed consent, the institutional review board approved this HIPAA-compliant, retrospective study of 193 women with histopathologically proven uterine papillary serous carcinomas (UPSC), uterine clear cell carcinomas (UCCC), and uterine carcinosarcomas (UCS) who underwent primary surgical resection between May 1998 and December 2011, and had a preoperative CT ≤ 6 weeks before surgery. All CT scans were reviewed for local or/and regional tumor extent, presence of pelvic or/and para-aortic adenopathy, and presence of distant metastases. Univariate survival analysis was performed using log-rank test and Cox regression. Variables shown significant by the univariate analysis were evaluated with the multivariable Cox regression analysis and the results were used to create a nomogram for predicting OS. The predictive accuracy of the nomogram was assessed with the concordance probability index (c-index) and a 3-year calibration plot. Results Mean patient age was 67.2 years (range 49.0–85.9); histologies included UPSC ( n  = 116), UCCC ( n  = 27), and UCS ( n  = 50). Median follow-up was 38.1 months (0.9–168.5 months). At multivariate analysis, patient age, ascites, and omental implants on CT were significant adverse predictors of OS and were used to build the nomogram. Concordance index for the nomogram was 0.640 ± 0.028. Conclusion We developed a nomogram with a good concordance probability at predicting OS based on readily available pretreatment clinical and imaging characteristics. This preoperative nomogram has the potential to improve initial treatment planning and patient counseling.

Description: Systemic diseases have many different presentations, including imaging findings in the bowel. Recognizing the imaging findings in these diseases is important in making the correct diagnosis. Although certain imaging features overlap, knowledge of specific findings along with the clinical presentation aid in narrowing the differential or in making an imaging diagnosis. The pictorial review will focus on the gastrointestinal manifestations of systemic diseases, including amyloidosis, angiotensin converter enzyme inhibitor-induced angioedema, celiac sprue, distal intestinal obstruction syndrome, graft-versus-host disease, hemolytic uremic syndrome, hemophilia, Henoch–Schönlein purpura, intestinal lymphangiectasia, mastocytosis, scleroderma, systemic lupus erythematosus, Wegener’s granulomatosis, and Whipple’s disease. The aforementioned diseases can be subdivided based upon the underlying process leading to the disease. The diseases discussed are categorized into autoimmune, infiltrative, treatment related, congenital/hereditary, and infectious etiologies.

Description: Biliary strictures and masses are commonly a result of cholangiocarcinoma. However, there are several congenital, infectious, inflammatory, autoimmune, iatrogenic, and neoplastic etiologies that should also be considered in the differential diagnosis. Knowledge of the key imaging and clinical findings will aid in facilitating the diagnosis and treatment.

Description: Purpose : The aim of this study was to investigate the diagnostic performance of contrast-enhanced CT (CECT) findings for bowel ischemia and necrosis in closed-loop small-bowel obstruction (CL-SBO). Materials and Methods : Thirty-five patients with CL-SBO confirmed by laparotomy ( n  = 34) or multiplanar reconstruction of thin slice CT images ( n  = 1) were included. Based on the surgical and clinical findings, these patients were classified into three groups: necrosis group ( n  = 16), ischemia without necrosis group ( n  = 11), and no-ischemia group ( n  = 8). Two blinded radiologists retrospectively reviewed CECT including multiplanar reconstruction images and evaluated 12 CT findings. The sensitivity and specificity of each finding were compared among the three groups, and logistic regression analysis was performed. Results : High attenuation of the bowel wall, intraperitoneal air, reduced enhancement of the mesenteric arteries, and small-bowel feces signs showed high specificities of 100%, 100%, 89%, and 89% but low sensitivities of 31%, 25%, 44%, and 31%, respectively, for the prediction of bowel necrosis in CL-SBO. According to multivariate logistic regression analysis, reduced bowel-wall enhancement, reduced enhancement of the mesenteric veins, and a lack of engorgement of the mesenteric veins were significant for predicting bowel ischemia or necrosis ( P  〈 0.05). Conclusions : Reduced enhancements of bowel wall and mesenteric veins were good indicators of bowel ischemia or necrosis. On the contrary, engorgement of the mesenteric veins was a predictor of a viable bowel.

Description: Purpose The purpose of this study was to compare fibrosis seen on liver biopsy to MR elastography (MRE) stiffness measurements in normal controls and patients with abnormal transaminases and chronic liver disease. Methods The control group consisted of 22 healthy liver transplant donors who by definition had normal transaminases. The patient group (32 patients) was recruited from the Mayo Clinic Arizona hepatobiliary clinic over a 3-year span. All subjects underwent a liver biopsy as part of their evaluation and agreed to MRE within 35 days of biopsy. Non-parametric tests were used to compare the MRE-predicted liver fibrosis to the fibrosis noted on liver biopsy. Results Analysis included 54 subjects (32 patients with chronic liver disease and 22 healthy liver donor candidates). MRE median liver stiffness measurements increased per histologic liver fibrosis stage (one-way ANOVA p  = 0.001), with significant correlation between increasing fibrosis stage and stiffness values. Median MRE for control group (2.13 kPa; mean = 2.3 ± 0.6 kPa) was significantly lower than for patient group (3.7 kPa; mean = 4.1 ± 2.1 kPa) ( p  = 0.003). Significantly, lower median stiffness was seen in zero-to-moderate (F0–2, n  = 22) vs. severe fibrosis stages (F3–4, n  = 10) 2.80 vs. 5.9 kPa, respectively ( p  〈 0.05). Using a 3.7-kPa cut-off value, the predicted sensitivity and specificity for detecting F0–2 from F3–4 were 91% and 80%, respectively. Conclusions Our analysis supports previous findings that MRE is a non-invasive and effective method for detection and assessment of liver fibrosis, particularly for discrimination between F0–2 stages and F3–4 stages. MRE may represent a valuable tool to finely discern hepatic fibrosis non-invasively.

Description: A central element was first described in focal nodular hyperplasia (FNH) as a so-called “central scar,” and is normally associated with this entity. However, many other liver masses may present with a central element. Depending on its appearance, and the lesion itself, central elements can be essential, helpful, or confusing for diagnosis. Indeed, nodules that develop on liver vascular disorders, fibrolamellar hepatocellular carcinoma, large hemangioma, peripheral cholangiocarcinoma, or epithelioid hemangioenthelioma often present with a central element, thus increasing the level of diagnostic confidence when present. On the other hand, central elements are rare or atypical in liver metastases, hepatocellular adenoma, or hepatocellular carcinoma. In this setting, the presence of a central element can lead to a misdiagnosis. The description and details of the imaging features of these different central elements, especially on MRI, as well as a thorough evaluation of the entire lesion, can improve the diagnostic performance in these cases.

Description: We report here a rare case of undifferentiated carcinoma of the pancreas mimicking main-duct intraductal papillary mucinous neoplasm. In an 80-year-old woman, an approximately 8-mm papillary mass was incidentally detected at the downstream edge of a dilatated main pancreatic duct lumen on CT and MRI. Main pancreatic duct dilatation in the pancreatic body and tail and parenchymal atrophy were observed in the upstream of the mass. Histopathologically, the tumor protruded into the downstream edge of the dilatated main pancreatic duct lumen in the pancreatic body. The tumor cells had highly atypical nuclei and abundant polymorphic structures, and showed positive staining for granulocyte colony-stimulating factor, which led to the diagnosis of undifferentiated carcinoma. A total of 13 cases of undifferentiated carcinoma with intraductal tumor growth have been reported to date. The case report by Bergmann et al. has been the smallest in histopathological specimen, and the present case is the smallest in size detected by radiological images. Since early undifferentiated carcinoma of the pancreas can resemble those of main-duct intraductal papillary mucinous neoplasm in cross-sectional images, we have to consider undifferentiated carcinoma in the differential diagnosis of the solitary and papillary mass with low contrast enhancement in early phase in the main pancreatic duct.

Description: Purpose The purpose of the study is to evaluate the influence of the adaptive iterative dose reduction (AIDR 3D) algorithm on the detectability of low-contrast focal liver lesions (FLLs) and the radiation dose repeatability of automatic tube current modulation (ATCM) in abdominal CT scans using anthropomorphic phantoms. Materials and Methods Three different sizes of anthropomorphic phantoms, each with 4 low-contrast FLLs, were scanned on a 320-channel CT scanner using the ATCM technique and AIDR 3D, at different radiation doses: full-dose, half-dose, and quarter-dose. Scans were repeated three times and reconstructed with filtered back projection (FBP) and AIDR 3D. Radiation dose repeatability was assessed using the intraclass correlation coefficient (ICC). Image noise, quality, and lesion conspicuity were assessed by four reviewers and the number of invisible FLLs was compared among different radiation doses and reconstruction methods. Results ICCs of radiation dose among the three CT scans were excellent in all phantoms (0.99). Image noise, quality, and lesion conspicuity in the half-dose group were comparable with full-dose FBP after applying AIDR 3D in all phantoms. In small phantoms, the half-dose group reconstructed with AIDR 3D showed similar sensitivity in visualizing low-contrast FLLs compared to full-dose FBP ( P  = 0.77–0.84). In medium and large phantoms, AIDR 3D reduced the number of missing low-contrast FLLs [3.1% (9/288), 11.5% (33/288), respectively], compared to FBP [10.4% (30/288), 21.9% (63/288), respectively] in the full-dose group. Conclusion By applying AIDR 3D, half-dose CT scans may be achievable in small-sized patients without hampering diagnostic performance, while it may improve diagnostic performance in medium- and large-sized patients without increasing the radiation dose.