Angela Geissler

Hepatic encephalopathy is a common problem in cirrhosis. The pathogenesis of this complication of advanced liver disease still remains unclear. Magnetic resonance spectroscopy was used to assess prospectively cerebral metabolism in 51 patients with histologically proven cirrhosis (Child–Pugh classes A, B, and C, 18, 18, and 15, respectively) and 36 healthy volunteers. According to the results of psychometric tests, overt hepatic encephalopathy, subclinical encephalopathy, and no encephalopathy were found in 14, 21, and 16 patients, respectively. Myoinositol/creatine ratios in gray (.36 ± .17) and white (.35 ± .22) matter voxel were reduced significantly ( P < .0001) in cirrhotic patients compared with healthy volunteers (gray matter, .51 ± .11; white matter, .64 ± .16). In addition, patients showed a significant reduction ( P = .024) in white matter choline/creatine ratio (.77 ± .27) compared with controls (.92 ± .25), and glutamine/glutamate level was elevated in cirrhotic patients compared with controls (gray matter, P < .0001; white matter, P = .036). Changes in cerebral myoinositol and glutamine/glutamate levels correlated significantly with the severity of hepatic encephalopathy ( P < .0001). However, these metabolic alterations were also detected in patients without hepatic encephalopathy (normal psychometric test results). N –acetyl aspartate/creatine ratios did not differ between patients and controls. Magnetic resonance imaging detected bright basal ganglia in 37 patients, which correlated significantly with portal–systemic shunting and elevation of glutamine/glutamate, but not with the degree of hepatic encephalopathy. In conclusion, magnetic resonance imaging and spectroscopy showed that alterations of cerebral metabolism are common in patients with cirrhosis, even without evidence of clinical or subclinical hepatic encephalopathy.

RATIONALE AND OBJECTIVES: Small bowel MRI (MR imaging) is a new imaging modality that excellently depicts small intestine pathology in patients with inflammatory bowel disease. Virtual endoscopy based on sectional imaging is a recently introduced technique to create endoscopy like views. The aim of this study was to evaluate the feasibility of virtual small bowel endoscopy based on MR imaging in patients with Crohn disease. MATERIALS AND METHODS: Thirty consecutive patients with Crohn disease were scanned after oral application of pineapple juice for contrasting the small bowel. Dedicated high resolution T1 weighted 3D-FLASH sequences with fat suppression were used for volume scanning. Volume-rendered 3D models of the small bowel were created and virtual endoscopy was performed. The feasibility and quality of this new visualization method was assessed. RESULTS: In nine of 30 patients virtual endoscopy was considered as good quality (flight through the entire small bowel was possible, typical folds were revealed). In 18 patients fair quality (at least 4/5 of the small bowel were depicted adequately) was assessed. In three of 30 patients virtual endoscopy was not sufficiently possible because of inadequate bowel filling or breathing artifacts. Three fistulae diagnosed on 2D MRI were visualized on the virtual endoscopic view. CONCLUSION: Virtual endoscopy of the small bowel is feasible based on high resolution MR imaging. Vivid insight views and 3D models provide an interesting addition to sectional MR findings.