Can-Hui Sun

Characterization of the middle hepatic artery and its relevance to living donor liver transplantation.

In comparison with the left and right hepatic arteries, there is a relative lack of information on the middle hepatic artery (MHA). In this study, data obtained by multidetector computed tomography from 145 patients were studied to evaluate anatomical variations of the MHA, a hilar artery that primarily supplies hepatic segment 4. An MHA was present in 103 (71%) of the subjects. In livers that had a replaced left hepatic artery, the MHA originated from the right hepatic artery; in livers that had a replaced right hepatic artery, it originated from the left hepatic artery. It always arose directly or indirectly from the common hepatic artery, from which the gastroduodenal artery also arose. We classified MHAs into 5 types according to the anatomical variations of the origin. This classification may have major relevance to modern surgical practice related to living donor liver transplantation (LDLT). The new classification of hepatic arterial anatomy may enhance the acquisition of further knowledge on arterial development, and its application may favorably influence the outcome of LDLT. Liver Transpl 16:736‐741, 2010.

Multiphasic MDCT in small bowel volvulus

OBJECTIVE Evaluate the use of MDCT with 3D CT angiography (CTA) and CT portal venography (CTPV) reconstruction for the diagnosis of small bowel volvulus (SBV). METHODS Multiphasic MDCT findings in nine patients (seven males and two females, age range 2-70) with surgically proven SBV were retrospectively reviewed. Non-contrast and double phase contrast enhanced MDCT including 3D CTA and CTPV reconstruction were performed in all the patients. Two experienced abdominal radiologists evaluated the images and defined the location, direction and degree of SBV. RESULTS On axial MDCT images, all cases show segmental or global dilatation of small intestine. Other findings include circumferential bowel wall thickening in eight cases, halo appearance and hyperemia in seven cases, whirl sign in six cases, beak-like appearance in six cases, closed loops in six cases and ascites in one case. CTA/CTPV showed abnormal courses involving main trunks of superior mesenteric artery (SMA) and superior mesenteric vein (SMV) in seven cases, with or without distortion of their tributaries. Normal course of SMA but abnormal course of SMV was seen in the other two cases. Of all the nine cases, whirl sign was seen in six cases and barbers pole sign in five cases. Dilated SMV was observed in eight cases and abrupt termination of SMA was found in one case. Compared with surgical findings, the location, direction and degree of SBV were correctly estimated in all cases based on CTA/CTPV. CONCLUSION Multiphasic MDCT with CTA/CTPV reconstruction can play an important role in the diagnosis of SBV. The location, direction and degree of SBV can all be defined preoperatively using this method.

Assessment of Activity of Crohn Disease by Diffusion-Weighted Magnetic Resonance Imaging.

AbstractTo assess the diagnostic efficacy of diffusion-weighted MR imaging (DWI) for evaluating inflammatory activity in patients with Crohns disease (CD). A total of 47 CD patients underwent MR enterography (MRE) and DWI using 3 b values of 50, 400, and 800 s/mm.2 Apparent diffusion coefficients (ADCs) of inflamed and normal bowel wall were calculated. The conventional MRE findings and DWI signal intensities were qualitatively scored from 0 to 3. The correlation between Crohn disease activity index (CDAI) and both ADCs and magnetic resonance imaging scores was analyzed. Receiver-operating characteristic curve analysis was used to determine the diagnostic accuracy of CD activity. Of the 47 patients, 25 were active CD (CDAI≥150) and 22 were inactive (CDAI<150). Diffusion-weighted MR imaging and MRE + DWI scores of active CD were significantly higher than that of inactive CD (both P < 0.001). Apparent diffusion coefficients in inflamed segments of active CD were lower than that of inactive CD (P < 0.001). The DWI scores (r = 0.74, P < 0.001), ADCs (r = −0.71, P < 0.001), MRE scores (r = 0.54, P < 0.001), and MRE + DWI scores (r = 0.66, P < 0.001) were all correlated with CDAI. The areas under the receiver-operating characteristics curves for ADCs, DWI scores, MRE scores, and MRE + DWI scores ranged from 0.83 to 0.98. The threshold ADC value of 1.17 × 10−3 mm2/s allowed differentiation of active from inactive CD with 100% sensitivity and 88% specificity. Diffusion-weighted MR imaging and ADC correlated with CD activity, and had excellent diagnostic accuracy for differentiating active from inactive CD.

CT and MR imaging characteristics of infantile hepatic hemangioendothelioma.

AIM This study aims to analyze computed tomography (CT) and magnetic resonance (MR) imaging features of infantile hepatic hemangioendotheliomas before and after treatment. MATERIALS AND METHODS CT and MR examinations of seven infants with biopsy proven hepatic hemangioendotheliomas were retrospectively analyzed. The distribution, number, size, imaging appearance, enhancement pattern and post-treatment changes of the tumors were evaluated. RESULTS A total of 153 hepatic hemangioendotheliomas were detected on CT (111) and MR (42) imaging. In six infants, 109/111 (98.2%) tumors were hypodense and 2/111 (1.8%) lesions contained calcification on unenhanced CT. On MR imaging, all 42 lesions in one infant were heterogeneously T1-hypointense and T2-hyperintense compared to the normal liver parenchyma. Contrast-enhanced CT and MRI showed peripheral rim (51.6%), uniform (48.4%), fibrillary (33.3%), and nodular (28.8%) contrast enhancement in the hepatic arterial phase. Homogeneous (100%), rim (98.2%) and mixed enhancement patterns were noted in tumors <1.0cm, >2.0cm and 1.0-2.0cm in diameter respectively in the hepatic arterial phase. In three patients who underwent steroid therapy, follow-up CT examination demonstrated tumor size reduction and increased intra-tumoral calcification in two patients. CONCLUSION Infantile hepatic hemangioendotheliomas show some typical imaging features and size-dependent pattern of contrast enhancement on CT and MR imaging, which allow accurate imaging diagnosis and post-treatment evaluation.

Characterization of Degree of Intestinal Fibrosis in Patients with Crohn Disease by Using Magnetization Transfer MR Imaging

Purpose To evaluate the role of magnetization transfer (MT) magnetic resonance (MR) imaging for the characterization of intestinal fibrosis compared with contrast material-enhanced and diffusion-weighted MR imaging and its capability for differentiating fibrotic from inflammatory strictures in humans with Crohn disease (CD) by using surgical histopathologic analysis as the reference standard. Materials and Methods Institutional review board approval and informed consent were obtained for this prospective study. Abdominal MT imaging, contrast-enhanced imaging, and diffusion-weighted imaging of 31 consecutive patients with CD were analyzed before elective surgery. The bowel wall MT ratio normalized to skeletal muscle, the apparent diffusion coefficient (ADC), and the percentage of enhancement gain were calculated; region-by-region correlations with the surgical specimen were performed to determine the histologic degree of fibrosis and inflammation. The performance of MT imaging was validated in five new patients. One-way analysis of variance test, Spearman rank correlation, and receiver operating characteristic curve were used for statistical analysis. Results Normalized MT ratios strongly correlated with fibrosis scores (r = 0.769; P = .000) but did not correlate with inflammation scores (r = -0.034; P = .740). Significant differences (F = 49.002; P = .000) in normalized MT ratios were found among nonfibrotic, mildly, moderately, and severely fibrotic walls. The normalized MT ratios of mixed fibrotic and inflammatory bowel walls were significantly higher than those of bowel walls with only inflammation present (t = -8.52; P = .000). A high accuracy of normalized MT ratios was shown with an area under the receiver operating characteristic curve (AUC) of 0.919 (P = .000) for differentiating moderately to severely fibrotic bowel walls from nonfibrotic and mildly fibrotic bowel walls, followed by ADC (AUC, 0.747; P = .001) and the percentage of enhancement gain (AUC, 0.592; P = .209). The sensitivity, specificity, and AUC of MT imaging for diagnosing moderate to severe fibrosis in the validation data set were 80% (12 of 15), 100% (three of three), and 0.9 (P = .033), respectively. Conclusion MT imaging outperforms ADC and contrast-enhanced imaging in detecting and distinguishing varying degrees of bowel fibrosis with or without coexisting inflammation. MT imaging could potentially be used as a method to differentiate fibrotic from inflammatory intestinal strictures in patients with CD.

Diffusion kurtosis MRI versus conventional diffusion‐weighted imaging for evaluating inflammatory activity in Crohn's disease

To assess the efficacy of diffusion kurtosis imaging (DKI) and to compare DKI‐derived parameters with that of conventional diffusion‐weighted imaging (DWI) for grading the inflammatory activity of Crohns disease (CD).

CT Findings of Intrarenal Yolk Sac Tumor with Tumor Thrombus Extending into the Inferior Vena Cava: A Case Report

Yolk sac tumor (YST) is a rare germ cell neoplasm of childhood that usually arises from the testis or ovary. The rare cases of YST in various extragonadal locations have been reported, but the primary intrarenal YST is even more uncommon. Here, we report a case of a primary intrarenal YST with tumor thrombus of the inferior vena cava and left renal vein in a 2-year-old boy, with an emphasis on the CT features. To our knowledge, this is the first reported case of an intrarenal YST with intravascular involvement.

Diagnostic and post-treatment CT appearance of biopsy proven mixed Cryptococcus and Candida cholangitis.

Cryptococcus neoformans and Candida are common opportunistic pathogens of human. There is very limited literature on Cryptococcus neoformans cholangitis or Candida cholangitis in immunocompetent patient while mixed Cryptococcus neoformans and Candida cholangitis has not been reported in the literature ever before. We hereby report the imaging findings of a case of mixed Cryptococcus neoformans and Candida cholangitis in an immunocompetent boy. The CT features included nodules in the cystic duct and common bile duct, dilatation of the intra- and extrahepatic bile ducts with mural thickening, irregular hypodense mass-like lesion extending along the bile ducts from the liver hilum to the periphery which was confirmed by the presence of enlarged and confluent lymph nodes. CT characteristics can contribute to timely diagnosis and treatment of this disease.

Sixty-four-slice computed tomography angiography of perigastric veins with image fusion.

Objective The objective of this study was to assess the efficacy and clinical value of 64-slice computed tomography angiography (CTA) with image fusion for demonstrating the perigastric venous anatomy. Methods Twenty-six patients with gastric cancer underwent abdominal CTA examinations. Computed tomography angiography of stomach and perigastric veins and arteries were reconstructed and fused using volume-rendering technique. The inflow and courses of perigastric veins as well as the spatial relationship among the perigastric veins, arteries, and stomach were compared with surgery. Results Compared with surgical findings, the visualization rate of the 7 perigastric veins on CTA was 90.9% to 100%. There was a statistically significant decrease in number of short gastric veins identified on CTA compared with surgery (P = 0.004). There was no statistically significant difference between the 2 modalities in detecting other perigastric veins including the left gastric vein, right gastric vein, right gastroepiploic vein, left gastroepiploic vein, posterior gastric vein, and gastrocolic trunk (P = 0.317, P = 0.157, P = 1, P = 1, P = 0.317, P = 1, respectively). Conclusions Sixty-four–slice CTA with image fusion clearly depicts most of perigastric veins and their relationship with the stomach and perigastric arteries. It can facilitate gastrectomy.

Quantitative assessment of perirectal tumor infiltration with dynamic contrast-enhanced multi-detector row CT in rectal cancer

OBJECTIVE To evaluate the efficacy of discriminant function analysis of perirectal tumor infiltration with dynamic contrast-enhanced 64-detector row CT in rectal cancer. MATERIALS AND METHODS Forty-nine patients with rectal cancer underwent dynamic contrast-enhanced CT. A total of 96 axial CT slices containing the tumors were evaluated. The 96 images were separated into two groups with or without perirectal tumor infiltration based on pathological findings. The discriminant function was set-up using CT density differences between the mass and the adjacent perirectal tissue within 5 mm from the mass at 20 and 40 s as independent variables. The results of the discriminant function analysis were compared to those of CT morphology and pathology. RESULTS CT morphological diagnosis was accurate on 71.9% (69/96) of the slices with 82.5% sensitivity and 64.3% specificity. Discriminant function analysis correctly identified 88.5% (85/96) of the slices with 85.0% sensitivity and 91.1% specificity. Overstaging occurred significantly more (P<0.05) on morphological analysis (20.8%, 20/96) than discriminant function analysis (5.2%, 5/96) of the CT slices. CONCLUSIONS Discriminant function analysis of dynamic contrast-enhanced CT improves the diagnostic accuracy and specificity of perirectal tumor infiltration in rectal cancer.