Crohn's disease evaluation: comparison of contrast-enhanced MR imaging and single-phase helical CT scanning.

The purpose of this study was to evaluate the use of gadolinium and barium-enhanced magnetic resonance (MR) imaging in detecting intestinal and extraintestinal Crohn's disease and compare MRI with contrast-enhanced helical computed tomography (CT). Twenty-six patients with Crohn's disease underwent imaging examinations, including gadolinium-enhanced, fat suppressed fast multiplanar spoiled gradient-recalled (FMPSPGR) MR imaging with oral 2% barium sulfate and rectal water and with helical CT using i.v. and positive (13) or negative (13) intestinal contrast material. MR images and CT scans were reviewed separately by two radiologists for bowel wall thickness and enhancement, presence of abscess, phlegmon, and fistula. MR images and CT scans were then compared side by side. Surgical, endoscopic, and histopathologic findings and results of barium studies were reviewed to determine the location and severity of involvement of intestinal Crohn's disease. Depiction of mural thickening and/or enhancement was superior on the MR images, which showed 55 (85%) and 52 (80%) of 65 abnormal bowel segments for the two observers, compared with helical CT, which showed 39 (60%) and 42 (65%; P < 0.001, P < 0.05) of bowel segments affected by Crohn's disease. Segments of bowel with moderate or marked mural thickening were depicted equally on MR imaging and helical CT. In mildly diseased segments of bowel, with only slight thickening and enhancement, MR imaging depicted 22 (79%) and 19 (68%) of 28 segments, compared with helical CT, which depicted 9 (32%; P < 0.01), and 13 (46%; P > 0.05) of 28 segments. In the side-by side comparison, MR imaging was preferred over helical CT for depicting normal bowel wall (MR 71%, CT 4%, equal 25%; P < 0.001), mural thickening (MR 41%, CT 11% equal 48%; P < 0.01), mural enhancement (MR 89%, equal 11%; P < 0.001), and overall GI tract evaluation (MR 52%, CT 10%, equal 38%; P < 0.001). Gadolinium-enhanced MR imaging with oral dilute barium sulfate and rectal water depicts intestinal and extraintestinal changes of Crohn's disease and shows promise as a clinically useful tool.

Portal vein thrombosis following endoscopic variceal sclerotherapy. Prospective controlled comparison in patients with cirrhosis.

The association between portal vein thrombosis (PVT) and prior endoscopic variceal sclerotherapy has been suggested but remains unproven. The aim of this study was to compare the incidence of PVT in patients who had received sclerotherapy for esophageal variceal hemorrhage to a control group of cirrhotic patients with portal hypertension who had not received sclerotherapy. Doppler ultrasound was used to assess PVT in 48 patients (group 1) who had received sclerotherapy for variceal hemorrhage as well as in 52 patients (group 3) with cirrhosis and portal hypertension who had not received sclerotherapy. Assessment of PVT was made at the time of surgery in 24 patients (group 2) who had received sclerotherapy for variceal hemorrhage, failed therapy, and had portacaval shunt surgery or received liver transplantation for liver failure. One patient had splenectomy for symptoms related to a massively enlarged spleen. The incidence of PVT in group 1 was 10%, in group 2 was 13%, and in group 3 was 10%. The incidence of PVT in the three groups was not significantly different statistically. In this controlled study of patients with cirrhosis and portal hypertension, sclerotherapy does not increase the incidence of PVT.

Mechanically and electrically evoked somatosensory potentials in humans: effects of stimulus presentation rate.

Somatosensory evoked potentials were recorded in response to: (1) electrical stimulation of the median nerve at the wrist; (2) electrical stimulation of the index finger; (3) mechanical stimulation of the index fingernail. Stimuli were presented at rates of 2, 4, 8, 16 and 32/sec, and the effects of presentation rate on components of the evoked potentials were evaluated. The effect of varying the duration of the mechanical stimulus was also observed. The findings suggest that stimulus rates of up to 8/sec can be used without significant loss in detectability of most of the components. The potentials recorded in response to a short duration mechanical stimulus were essentially identical to those evoked by the long duration stimulus. The findings of this study are consistent with a peripheral nerve generator for the Erb's point recorded component, a postsynaptic generator for the upper neck recorded component, and in general with a larger number of synapses leading to the generators of the later components than to earlier ones.

Mechanically and electrically evoked somatosensory potentials in normal humans.

Somatosensory potentials evoked by mechanical stimulation of the fingernail and electrical stimulation of the nerve in the finger and at the wrist were recorded by surface electrodes over; (1) the digital nerve in the index finger, (2) the median nerve at the wrist, (3) the median nerve at the axilla, (4) the brachial plexus at Erb's point, (5) the cervical cord at C2, and (6) the scalp overlying the somatosensory cortex. Nerve conduction velocities were computed for two portions of the median nerve. Conduction times along the somatosensory pathway between spinal cord and cerebral cortex were also defined. The mechanically evoked potentials had less temporal dispersion, were of lower amplitude, and occasionally consisted of fewer components than the electrically evoked potentials. Electrical stimulation of the nerve trunk at the wrist evoked some additional components not detected by the other stimulation methods. Nerve conduction velocities and conduction times were comparable among the three methods of stimulation.