Korosh Khalili

IgG4-related Sclerosing Disease: Autoimmune Pancreatitis and Extrapancreatic Manifestations

Autoimmune pancreatitis is the pancreatic manifestation of IgG4-related sclerosing disease, which recently was recognized as a distinct disease entity. Numerous extrapancreatic organs, such as the bile ducts, gallbladder, kidneys, retroperitoneum, thyroid, salivary glands, lung, mediastinum, lymph nodes, and prostate may be involved, either synchronously or metachronously. Most cases of autoimmune pancreatitis are associated with elevated serum IgG4 levels; extensive IgG4-positive plasma cells; and infiltration of lymphocytes into various organs, which leads to fibrosis. There are several established diagnostic criteria systems that are used to diagnose autoimmune pancreatitis and that rely on a combination of imaging findings of the pancreas and other organs, serologic findings, pancreatic histologic findings, and response to corticosteroid therapy. It is important to recognize multiorgan involvement of IgG4-related sclerosing disease and be familiar with its clinical and imaging features because it demonstrates a favorable response to treatment.

Optimization of imaging diagnosis of 1-2 cm hepatocellular carcinoma: an analysis of diagnostic performance and resource utilization.

BACKGROUND & AIMS To determine the optimal imaging scan or combinations in terms of diagnostic performance and resource utilization for 1-2 cm nodules found on surveillance for hepatocellular carcinoma. METHODS Eighty-four cirrhotic patients with 101, 1-2 cm nodules (34 malignant, 67 non-malignant) prospectively underwent standardized contrast-enhanced ultrasound, CT, and MRI scans. Sensitivity/specificity and potential imaging/biopsy utilization of individual imaging modalities and two-modality combinations performed at the same time (coincidental) or in sequence were measured. Final diagnosis was determined by biopsy (23), growth (10), recurrence (1), or stability in size for ≥ 18 months (67). RESULTS For single imaging scans, sensitivities/specificities ranged between 53-62% and 91-100%. When two scans were combined requiring both to be positive, sensitivities/specificities ranged between 29-41% and 99-100%. When two scans were combined sequentially, requiring only one to be positive, sensitivities/specificities ranged between 74-89% and 91-99%. When comparing combination of two positive tests (MRI and CT) to MRI alone, there was a significant drop in sensitivity (41% vs. 62%, p=0.02), no change in specificity (both 100%), with twice as many scans performed, and 9% rise in potential biopsies or 7% rise in follow-up scans. When comparing the combination of MRI then CT (if MRI negative) to MRI alone, there was an insignificant rise in sensitivity (74% vs. 62%, p=0.13), drop in specificity (97% vs. 100%), with 77% more scans performed, and 6% drop in potential biopsies or 7% drop in potential follow-up scans. CONCLUSIONS Single imaging scans have similar specificity to two coincidental positive scans with much less resource utilization. Sequential imaging provides the best sensitivity but with diminished specificity.

Analysis of Gadobenate Dimeglumine–enhanced MR Findings for Characterizing Small (1–2-cm) Hepatic Nodules in Patients at High Risk for Hepatocellular Carcinoma

PURPOSE To retrospectively identify magnetic resonance (MR) imaging findings that are associated with hepatocellular carcinoma (HCC) in 1-2-cm nodules detected at surveillance ultrasonography (US) and to propose newer MR imaging diagnostic criteria. MATERIALS AND METHODS Institutional research ethics board approval was obtained, and informed patient consent was waived. Among 145 consecutive patients who had 1-2-cm nodules that were newly detected at surveillance US, 108 patients underwent gadobenate dimeglumine-enhanced MR imaging. After excluding hemangiomas and unconfirmed nodules, the study sample comprised 96 patients with 116 nodules, including 43 HCCs and 73 benign nodules. MR imaging findings were assessed for signal intensity at each sequence. On the basis of the results of univariate and multivariable logistic regression analyses, several diagnostic criteria were developed by using combinations of MR imaging findings, which were then compared with the American Association for the Study of Liver Diseases (AASLD) practice guideline. RESULTS Univariate analysis revealed four imaging findings associated with HCC, including arterial phase hyperintensity, portal or delayed phase hypointensity (washout), hyperintensity on T2-weighted images, and hepatobiliary phase hypointensity (P < .001 for each). In the multivariable analysis, arterial phase hyperintensity (adjusted odds ratio [OR], 17.1; P = .003) and washout (adjusted OR, 11.7; P = .007) were associated with HCC. Of the developed criteria, the criteria including nodules fitting the AASLD practice guideline (arterial phase hyperintensity and washout) or nodules having three or more findings were considered most reasonable, showing improved sensitivity (77% [33 of 43] versus 67% [29 of 43], P = .048) and comparable specificity (95% [69 of 73] versus 99% [72 of 73], P = .09), as compared with AASLD practice guideline. CONCLUSION Alternative MR imaging criteria for diagnosing HCC in 1-2-cm nodules detected at surveillance US that can improve sensitivity compared with the AASLD practice guideline were proposed. A larger study is needed to verify the preliminary criteria in this study. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101549/-/DC1.

Imaging Features of Sclerosed Hemangioma

OBJECTIVE The purpose of this study was to review the imaging features of sclerosed hemangioma. CONCLUSION In our series, suggestive features of sclerosed hemangiomas include geographic outline, capsular retraction, decrease in size over time, and loss of previously seen regions of enhancement. Additional features include presence of transient hepatic attenuation difference (THAD), rim enhancement, and nodular regions of intense enhancement as seen in typical hemangiomas. Although not pathognomonic, some features of sclerosed hemangioma can suggest it as a diagnostic possibility and lead to biopsy rather than more extensive intervention.

Non-invasive diagnosis of advanced fibrosis and cirrhosis

Liver cirrhosis is a common and growing public health problem globally. The diagnosis of cirrhosis portends an increased risk of morbidity and mortality. Liver biopsy is considered the gold standard for diagnosis of cirrhosis and staging of fibrosis. However, despite its universal use, liver biopsy is an invasive and inaccurate gold standard with numerous drawbacks. In order to overcome the limitations of liver biopsy, a number of non-invasive techniques have been investigated for the assessment of cirrhosis. This review will focus on currently available non-invasive markers of cirrhosis. The evidence behind the use of these markers will be highlighted, along with an assessment of diagnostic accuracy and performance characteristics of each test. Non-invasive markers of cirrhosis can be radiologic or serum-based. Radiologic techniques based on ultrasound, magnetic resonance imaging and elastography have been used to assess liver fibrosis. Serum-based biomarkers of cirrhosis have also been developed. These are broadly classified into indirect and direct markers. Indirect biomarkers reflect liver function, which may decline with the onset of cirrhosis. Direct biomarkers, reflect extracellular matrix turnover, and include molecules involved in hepatic fibrogenesis. On the whole, radiologic and serum markers of fibrosis correlate well with biopsy scores, especially when excluding cirrhosis or excluding fibrosis. This feature is certainly clinically useful, and avoids liver biopsy in many cases.

Comparative MRI Analysis of Morphologic Patterns of Bile Duct Disease in IgG4-Related Systemic Disease Versus Primary Sclerosing Cholangitis

OBJECTIVE The purpose of this study was to perform a retrospective MRI-based comparative analysis of the morphologic patterns of bile duct disease in IgG4-related systemic disease (ISD, also called autoimmune pancreatitis) compared with primary sclerosing cholangitis (PSC) and the autoimmune liver diseases autoimmune hepatitis and primary biliary cirrhosis. MATERIALS AND METHODS This study included 162 consecutively registered patients (47 with ISD, 73 with PSC, and 42 with autoimmune liver diseases). Two abdominal radiologists retrospectively reviewed MR images in consensus. Imaging findings on the bile ducts, liver, pancreas, and other organs were analyzed to establish disease patterns. RESULTS ISD was associated with contiguous thickening of intrahepatic and extrahepatic bile ducts (p<0.001), pancreatic parenchymal abnormalities (p<0.001), renal abnormalities (p<0.001), and gallbladder wall thickening (p<0.03). The severity of common bile duct wall thickness was significantly different in ISD (p<0.001). The mean single wall thickness in the ISD group was 3.00 (SD, 1.47) mm, in the PSC group was 1.89 (SD, 0.73) mm, and in the autoimmune liver disease group was 1.80 (SD, 0.67) mm. PSC was associated with liver parenchymal abnormalities (p<0.001). We did not find statistical significance between the three groups in location (p=0.220) or length (p=0.703) of extrahepatic bile duct strictures, enhancement of bile duct stricture (p=0.033), upper abdominal lymphadenopathy, or retroperitoneal fibrosis. Although presence of intrahepatic bile duct stricture was statistically significant when all three groups were compared, it was not useful for differentiating ISD from PSC. CONCLUSION The presence of continuous as opposed to skip disease in the bile ducts, gallbladder involvement, and single-wall common bile duct thickness greater than 2.5 mm supports a diagnosis of ISD over PSC. ISD and PSC could not be differentiated on the basis of location and length of common bile duct stricture.

Contrast-enhanced computed tomography for the diagnosis of fatty liver: prospective study with same-day biopsy used as the reference standard

Purpose: The study purpose was to prospectively determine the accuracy of contrast-enhanced CT in diagnosing fatty liver using same-day biopsy as the reference standard. Materials and methods: One hundred seventy-nine potential living liver donors underwent unenhanced and portal-phase contrast-enhanced hepatic CT and subsequent liver biopsy on the same day. Attenuation difference between the liver and the spleen on unenhanced (preL-S) and contrast-enhanced (postL-S) images and blood-subtracted hepatic attenuation on contrast-enhanced images (postL-B), calculated by [L - 0.3 × (0.75 × P + 0.25 × A)]/0.7 where L, P and A represent the attenuation of the liver, main portal vein and abdominal aorta, respectively, were obtained. The accuracy of these indices in diagnosing fatty liver according to various threshold levels, 5%-30% histological steatosis in increments of 5%, was compared using ROC analysis. Results: The area under the ROC curve for preL-S, postL-S and postL-B was 0.663–0.918, 0.712–0.847 and 0.821–0.923, respectively, depending on the threshold levels of hepatic steatosis. The accuracy of preL-S and postL-S did not differ (P ≥ 0.054), despite a trend towards a lower accuracy with postL-S. postL-B yielded higher accuracy than preL-S at threshold levels of 5% and 10% (P ≤ 0.002) and similar accuracy to preL-S at the other threshold levels (P ≥ 0.144). Conclusion: Portal-phase contrast-enhanced CT has a similar, or even greater, accuracy than unenhanced CT in diagnosing fatty liver.

Pseudoenhancement Within the Local Ablation Zone of Hepatic Tumors Due to a Nonlinear Artifact on Contrast-Enhanced Ultrasound

OBJECTIVE Pseudoenhancement of an avascular region on contrast-enhanced ultrasound often occurs within an echogenic region of a radiofrequency ablation zone due to nonlinear ultrasound propagation through intervening microbubble-perfused tissue. The purpose of this study was to describe the imaging features of this artifact. MATERIALS AND METHODS Twenty-six patients with no tumor recurrence within ablation zones were included. Two radiologists assessed contrast-enhanced ultrasound pseudoenhancement in the arterial (< 30 seconds), portal (30-90 seconds), and late (> 90 seconds) phases. If pseudoenhancement was present, the following information was recorded: the degree, time to first appearance, progression over time, and location. The corresponding gray-scale echogenicity (hypo-, iso-, or hyperechoic) and lesion depth were also noted. RESULTS Fourteen lesions (14/26, 54%) showed pseudoenhancement on contrast-enhanced ultrasound. Fourteen (100%) corresponded to the hyperechoic area within the ablation zone on gray-scale ultrasound and were nonmarginal in location. Pseudoenhancement occurred more frequently in deep lesions (> or = 5 cm) than in superficial lesions (< 5 cm) (p = 0.002). Pseudoenhancement was initiated most frequently in the portal phase (9/14, 64%), followed by the arterial phase (4/14, 29%) and late phase (1/14, 7%). Progression in the degree of pseudoenhancement was shown in most cases (12/14, 86%) and no washout was seen. CONCLUSION Pseudoenhancement is frequently seen within ablation zones on contrast-enhanced ultrasound, particularly in deep echogenic lesions. However, pseudoenhancement follows enhancement of the parenchyma between the transducer and target. This observation is consistent with nonlinear propagation of the ultrasound beam, which increases with bubble concentration. Pseudoenhancement shows relatively late initiation, progression over time, and nonmarginal location; these findings are different from those seen in typical tumor recurrence, which shows early enhancement and washout at the margin of the ablation zone.

Impact of Regional Lymph Node Evaluation in Staging Patients With Periampullary Tumors

BackgroundTwo distinct lymph nodes reproducibly assessed by computed tomography for the evaluation of periampullary tumors are the common bile duct (CBD) node and the gastroduodenal artery (GDA) node. We examined whether radiographical enlargement of either lymph node predicts tumor resectability, nodal metastasis, or patient survival.MethodsNinety-four consecutive patients underwent attempted curative resection of periampullary tumors between September 2001 and June 2003. A single radiologist recorded in a retrospective, blinded fashion the short- and long-axis measurements of the CBD and GDA nodes.ResultsSixty-one percent (n = 57) of tumors were resectable by pancreaticoduodenectomy. Overall, actual 6-, 12-, and 18-month survival was 87%, 68%, and 63%, respectively. Enlarged radiographical nodal size by either axis was not associated with the presence of metastasis to these lymph nodes or with reduced overall patient survival. Only a CBD node short-axis size >10 mm predicted unresectability (odds ratio, 3.2; P = .036). Liver metastasis and/or carcinomatosis were present in 43% of unresectable patients, and this was associated with decreased survival at both 1 year (25% vs. 77%; P < .001) and 18 months (19% vs. 72%; P <.001). A pathologic diagnosis of metastasis to the GDA node, but not the CBD node, was associated with a similarly decreased survival (1 year: 33% vs. 78%, P = .028; 18 months: 22% vs. 70%, P = .023).ConclusionsFor presumed periampullary malignancy, a CBD node short-axis size >10 mm predicts tumor unresectability. Metastatic disease to the GDA node, particularly for pancreatic adenocarcinoma, portends a poor prognosis equivalent to that of hepatic or peritoneal spread. Given these findings, radiographical CBD lymph node measurements may guide selection for performing laparoscopic staging with or without ultrasonography in conjunction with GDA nodal biopsy in patients with periampullary malignancy.

Chondroblastoma with multiple distant soft tissue metastases

Abstract A case of metachronous distant soft tissue metastases from a primary rib chondroblastoma, occurring in a 60-year-old man 17 years following resection of the initial lesion, is described. Metastatic chondroblastomas are very rare and almost always involve the lungs. Discussed herein are the clinical, radiologic, and pathologic findings of this unusual case with comparison of our findings to other reports of metastasizing chondroblastomas.