Maria Sheridan

OBJECTIVE: The purpose of this study was to compare dynamic contrast-enhanced MR imaging and dual-phase helical CT in the preoperative assessment of patients with suspected pancreatic carcinoma. SUBJECTS AND METHODS: Thirty-three consecutive surgical candidates (20 men, 13 women; 39-81 years old) were included. MR imaging comprised fast spin-echo (TR/TE 4000/91), fat-suppressed T1-weighted spin-echo (500/15), and T1-weighted breath-hold gradient-echo fast low-angle shot (100/4; flip angle, 80 degrees) images before and after the administration of gadopentetate dimeglumine. Helical CT used 5-mm collimation with a pitch of 1:1.5-1.7; images were obtained 20 and 65-70 sec after injection of 150 ml of contrast material. Two pairs of interpreters who were unaware of the results of the other imaging method independently scored each examination for the presence of a lesion and for surgical resectability using a five-point scale. Results were correlated with surgery (n = 25) or consensus review (n = 8). Receiver operating characteristic methodology was used to analyze the results for resectability, and positive predictive values were calculated. RESULTS: Both MR imaging and helical CT revealed 29 of 31 lesions. In determining lesion resectability, the mean areas under the receiver operating characteristic curves were 0.96 and 0.81 (p = .01) and the positive predictive values were 86.5% and 76% (p = .02) for MR imaging and helical CT, respectively. CONCLUSION: MR imaging and helical CT performed equally well in lesion detection. MR imaging was significantly better in the assessment of resectability of pancreatic tumors.

OBJECTIVE: To examine the effects of cholestatic jaundice on gut barrier function. SUMMARY BACKGROUND DATA: Gut barrier failure occurs in animal models of jaundice. In humans, the presence of endotoxemia indirectly implicates failure of this host defense, but this has not previously been investigated in jaundiced patients. METHODS: Twenty-seven patients with extrahepatic obstructive jaundice and 27 nonicteric subjects were studied. Intestinal permeability was measured using the lactulose-mannitol test. Small intestinal morphology and the presence of mucosal immunologic activation were examined in endoscopic biopsies of the second part of the duodenum. Systemic antiendotoxin core IgG antibodies and serum interleukin-6 and C-reactive protein were also quantified. Intestinal permeability was remeasured in 9 patients 5 weeks after internal biliary drainage. RESULTS: The median lactulose-mannitol ratio was significantly increased in the jaundiced patients. This was accompanied by upregulation of HLA-DR expression on enterocytes and gut-associated lymphoid tissue, suggesting immune activation. A significant increase in the acute phase response and circulating antiendotoxin core antibodies was also observed in the jaundiced patients. After internal biliary drainage, intestinal permeability returned toward normal levels. CONCLUSIONS: A reversible impairment in gut barrier function occurs in patients with cholestatic jaundice. Increased intestinal permeability is associated with local immune cell and enterocyte activation. In view of the role of gut defenses in the modern paradigm of sepsis, these data may directly identify an important underlying mechanism contributing to the high risk of sepsis in jaundiced patients.

PURPOSE: To assess the predictive value of superparamagnetic iron oxide (SPIO) -enhanced T2-weighted gradient echo (GRE) imaging to determine the presence and severity of sinusoidal obstructive syndrome (SOS). PATIENTS AND METHODS: Sixty hepatic resection patients with colorectal metastases treated with chemotherapy underwent unenhanced magnetic resonance imaging (MRI) followed by T2-weighted GRE sequences obtained after SPIO. The images were reviewed in consensus by two experienced observers who determined the presence and severity of linear and reticular hyperintensities, indicating SOS-type liver injury, using a 4-point ordinal scale. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) with 95% CIs for the detection of SOS were calculated. RESULTS: Twenty-four of 60 patients had moderate to severe SOS on MRI. MRI achieved a sensitivity of 87% (95% CI, 66% to 97%), specificity of 89% (95% CI, 75% to 97%), PPV of 83% (95% CI, 63% to 95%), and NPV of 92% (95% CI, 77% to 98%). SOS was never found at surgery or histology in patients whose background liver parenchyma was normal on SPIO-enhanced MRI. CONCLUSION: SOS is present in a significant proportion of patients with treated colorectal metastases and is effectively detected on SPIO-enhanced T2-weighted GRE images.