Radiologic features of pancreatic and biliary complications following composite visceral transplantation.

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.

Utility of additional CT examinations driven by completion of a standard trauma imaging protocol in patients transferred for minor trauma.

Many clinicians order focused computed tomography (CT) examinations for trauma patients based on history and physical examinations. Trauma patients transferred to our level I trauma center undergo an extensive, nonfocused standard trauma CT protocol. We hypothesize that the use of the standard trauma CT protocol does not contribute significant clinical information for patient care when compared with CT examinations based on history and physical examination. We aim to quantify the utility of the additional CT examinations required by our institution's trauma protocol compared with emergent CT examinations dictated by the patient's history and physical examination findings. In this IRB-approved study, we retrospectively evaluated 132 trauma patients transferred to our center who underwent additional CT examinations as determined by fulfillment of our institution's standard trauma CT protocol. The emergency radiologist evaluated the CT examinations acquired after the patient's transfer to determine if there were any additional acute findings that were identified on these additional examinations compared with the initial assessment undertaken at the outside institution. A total of 101 patients transferred to our trauma center met inclusion criteria. The majority of these patients sustained minor trauma. The standard trauma protocol generated 474 negative CT examinations in 101 patients. In seven patients, there were unexpected acute findings. However, these unexpected acute findings did not change clinical management in any of the patients. After initial evaluation, the acquisition of additional nonfocused CT examinations based on the standard trauma CT protocol provides little useful clinical information in patients who are transferred for minor trauma. Rather, CT utilization should be based on clinical findings. Replacement of standard trauma CT protocol with focused CT examinations in trauma patients is a way to curtail overutilization, thereby decreasing health care cost and the amount of patient radiation exposure.

Regional presentation of hepatic diseases: CT and MR imaging findings of differential diagnosis.

Neoplastic and nonneoplastic diseases may involve the liver with a regional distribution, which is defined as a non-focal process without any specific anatomic predilection. In this pictorial essay we review hepatic diseases commonly presenting with a regional distribution in the liver and describe the CT and MR imaging findings helpful for differential diagnosis. Knowledge of the characteristic imaging manifestations of neoplastic and non-neoplastic diseases affecting the liver regionally will facilitate an accurate diagnosis and result in the appropriate clinical management of these liver diseases.

Imaging of posttransplantation lymphoproliferative disorder after solid organ transplantation.

Posttransplantation lymphoproliferative disorders (PTLDs) are a heterogeneous group of diseases that represent uncommon complications of transplantation and can lead to significant morbidity and mortality. PTLD is most prevalent during the first year following transplantation and occurs most frequently in multiorgan transplant recipients, followed by bowel, heart-lung, and lung recipients. It may involve any of the organ systems, with disease manifestation and the anatomic pattern of organ involvement being highly dependent on the type of transplantation. The current classification system includes four subtypes that have different prognoses requiring different treatment strategies. Tissue sampling is necessary for diagnosis and further subcategorization. The majority of cases are characterized by B-cell proliferation and are related to infection from Epstein-Barr virus. Knowledge of the distribution and radiologic features of PTLD allows the radiologist to play a pivotal role in making an early diagnosis and in guiding biopsy.

2D thick-slab MR cholangiopancreatography: does parallel imaging with sensitivity encoding improve image quality and duct visualization?

OBJECTIVE: Our objective was to determine whether the theoretic advantages of parallel imaging are realized when applied to 2D thick-slab single-shot fast spin-echo (SSFSE) MR cholangiopancreatography (MRCP) with respect to image quality and duct conspicuity. MATERIALS AND METHODS: Thirty-nine patients (18 men and 21 women; mean age, 51.8 years) were referred for MRCP. Multiangled thick-slab breath-hold SSFSE imaging was performed without and with integrated parallel imaging with sensitivity encoding (SENSE). Images were retrospectively reviewed. A 4-point rating scale was used to grade overall image quality and visibility of 10 ductal segments. A Wilcoxon's signed rank test compared the two techniques. Analysis of signal intensities and relative contrast of fluid-filled structures to background tissue on the basis of region of interest was calculated. Differences between the techniques were compared using a Student's t test. RESULTS: Two-dimensional thick-slab SSFSE with integrated parallel imaging showed a mild but statistically significant increase in the relative contrast (p = 0.01) of ductal segments. Image quality deteriorated slightly with parallel imaging, but the results were not statistically significant (p = 0.06). Parallel imaging improved duct conspicuity of the medial and lateral segments of the left lobe and the posterior segment of the right lobe. However, statistical improvement was achieved only for the medial segment of the left lobe (p = 0.03). The mean scores of the remaining ducts were either unchanged or worse with parallel imaging, but the differences were not significant. CONCLUSION: Although there was improvement in the relative contrast of bile to background tissue, improvement in overall image quality was not observed with parallel imaging. However, application of parallel imaging to thick-slab SSFSE may improve depiction of the smallest-caliber ducts.

Protocol considerations for positron emission tomography-computed tomography of the abdomen and pelvis.

New developments in positron emission tomography-computed tomography (PET-CT) have included the introduction of scanners with multidetector 16- to 64-row CT that allow thin-section essentially isotropic imaging datasets to be acquired rapidly in multiple time phases. "Diagnostic quality" CT with both oral and intravenous enhancement is now routinely possible in PET-CT and allows greater potential for the accurate diagnosis and staging of the full range of cancers involving the abdomen and pelvis. This article explores the considerations for more tailored, specific tumor-related protocols for PET-CT in the abdomen and pelvis, with emphasis on the use and value of fully optimized CT as part of an integrated PET-CT examination.

A radiogenomic analysis of hepatocellular carcinoma: association between fractional allelic imbalance rate index and the liver imaging reporting and data system (LI-RADS) categories and features.

OBJECTIVE: To evaluate the association between the liver imaging reporting and data system (LI-RADS) categories and features and the fractional allelic imbalance (FAI) rate index of hepatocellular carcinoma (HCC). METHODS: The institutional review board approved this retrospective study. Medical records collected between January 2008 and December 2013 were reviewed to find patients with histologically confirmed HCC, FAI analysis, and CT or MR imaging of the liver. The final population included 71 patients (54 males, 17 females). Three radiologists reviewed the images using the LI-RADS v. 2014. The association between FAI and LI-RADS categories and features was tested using the Spearman's rank correlation coefficient (rho) and the Wilcoxon rank-sum test [low FAI (<40%) vs high FAI (≥40%)]. A p value < 0.007 was used as the threshold for statistical significance after application of the Bonferroni correction for multiple comparisons. RESULTS: HCCs were classified as LR-3 (n = 4), LR-4 (n = 22), and LR-5 (n = 45). There was a positive correlation (rho = 0.264) between FAI rate index and LI-RADS category, although not statistically significant after Bonferroni correction (p = 0.024). 14 of the 20 (70%) HCCs with high FAI (≥40%) were categorized as LR-5, 6/20 (30%) as LR-4 and none as LR-3 (p = 0.377). Among the evaluated LI-RADS imaging features, only lesion size showed a statistically significant different distribution in tumors with high FAI compared to those with low FAI. HCCs with FAI ≥40% were larger (56 ± 42 mm) compared to those with FAI <40% (36 ± 30 mm; p = 0.005). CONCLUSION: There was a positive correlation, although not statistically significant, between the LI-RADS diagnostic categories and the FAI rate of HCC. Tumors with high FAI were larger compared to those with low FAI. Advances in knowledge: HCCs with high (≥40%) FAI are larger compared to those with low (<40%) FAI.

Tuberculous peritonitis.

Tuberculous peritonitis is a serious condition with rising prevalence in recent years. It is especially common in those patients with risk factors such as an immunocompromised state, chronic kidney disease, or cirrhosis/liver disease. Spread is typically hematogenous from pulmonary foci. We report on a 34-year-old man who presented with initial complaints of cough, low-grade fevers, abdominal pain, and nausea/vomiting. Chest x-ray showed a cluster of nodular opacities on the right upper lobe, and a CT scan showed diffuse thickening and nodularity of the omentum with prominent mesenteric lymph nodes, consistent with tuberculous peritonitis.

Abdominal imaging and intervention in liver transplantation.

Diagnostic imaging and interventional radiology play key roles in the evaluation and management of patients who are being evaluated for potential liver transplantation (LTX) and of those who have received a transplanted liver. Technical advances in imaging equipment and technique allow more accurate assessment and often obviate unnecessary or nontherapeutic surgery or invasive techniques such as catheter angiography.

Radiologists' performance in the diagnosis of liver tumors with central scars by using specific CT criteria.

PURPOSE: To determine the performance of radiologists with differing levels of expertise in the diagnosis of the most common types of liver tumors with central scars (ie, focal nodular hyperplasia [FNH], fibrolamellar hepatocellular carcinoma [HCC], and large hepatic hemangioma) by using specific computed tomographic (CT) findings. MATERIALS AND METHODS: Review of medical records at the University of Pittsburgh Medical Center identified patients with a total of 64 liver tumors that had central scars-including 29 cases of FNH, 20 fibrolamellar HCCs, and 15 large (>3.5 cm in diameter) hemangiomas-and with CT scans available for review. Retrospective review of these scans was performed individually by six radiologists who were blinded to the diagnosis, including two faculty abdominal radiologists, one abdominal imaging fellow, and three radiology residents. Individual performance was evaluated by means of receiver operating characteristic analysis, and interobserver agreement was measured by using the Cronbach alpha. Individual CT findings that may allow differentiation of tumor types were identified with the Kruskal-Wallis test. RESULTS: CT allowed good to excellent interobserver agreement in the diagnosis of tumor type and in recognition of differential findings among the three types. The individual accuracy of diagnosis was very good, with the average area under the receiver operating characteristic curve ranging from 0.81 to 0.90. Although the faculty radiologists performed the best, the differences in performance between the subgroups of readers and the levels of confidence in diagnosis were not statistically significant. The diagnosis of fibrolamellar HCC was the most accurate and had the highest sensitivity, followed by FNH and large hemangioma. Clinical and CT findings that were found to be statistically significant in differentiating tumor types were patient age and sex, tumor size larger than 10 cm, width of tumor scars, invasion of vessels, nodular centripetal enhancement, marked hyperattenuation on arterial phase images, lymphadenopathy, heterogeneity, extrahepatic metastases, surface lobulation, calcification, and isoattenuation with liver tissue on portal venous phase images. CONCLUSION: CT allows accurate differentiation of the most common types of liver tumors with central scars, including FNH, fibrolamellar HCC, and large hemangioma.