Intraluminal irradiation for TIPS stenosis: preliminary results in a swine model.

PURPOSE: To evaluate the ability of 32phosphorus intraluminal irradiation to reduce pseudointimal hyperplasia in a transjugular intrahepatic portosystemic shunt (TIPS). MATERIALS AND METHODS: TIPS were successfully placed in 11 swine with normal portal pressures. Six animals received 15.2 Gy intraluminal irradiation to the hepatic parenchyma and venous outflow tract at the time of TIPS placement with use of a NA32P-filled balloon angioplasty catheter. Five control animals underwent TIPS and balloon angioplasty with saline. All animals were followed up for 28 days, at which time percutaneous portography was performed, the animals were killed, and the tissue around the TIPS stent was processed for histologic analysis. Maximum pseudointimal hyperplasia as a percentage of estimated TIPS diameter was calculated for each animal. RESULTS: At the time of euthanasia, all five control TIPS and all but one irradiated TIPS were occluded. Histologic analysis demonstrated considerable variability in the degree of pseudointimal hyperplasia within each TIPS and between animals. No statistically significant difference was found in the maximum pseudointimal hyperplasia, measured as a percentage of stent radius, between control (80.2%+/-17.4%) and irradiated animals (69.2%+/-25.2%). CONCLUSIONS: Irradiation of TIPS with 15.2 Gy 32P delivered at the time of TIPS placement did not significantly improve TIPS patency or reduce the degree of pseudointimal hyperplasia in swine with normal portal pressures.

The fornix in patients with seizures caused by unilateral hippocampal sclerosis: detection of unilateral volume loss on MR images.

OBJECTIVE: Because some of the axons of the fornix originate in the pyramidal cells of the hippocampus, we hypothesize that neuronal loss within the hippocampus may result in wallerian degeneration and subsequent atrophy of the ipsilateral fornix. Using high-resolution MR imaging, we evaluated the size of the fornix in patients who had lateralizing partial complex temporal lobe seizures after unilateral hippocampal sclerosis. The expectation is that unilateral forniceal atrophy will provide an additional, objective imaging criterion for determining the side of seizure involvement. MATERIALS AND METHODS: We retrospectively reviewed preoperative MR images of 13 patients with temporal lobe epilepsy who subsequently had unilateral hippocampal sclerosis proved surgically. The images were obtained with specially designed bilateral phased-array coils that permitted high-resolution (512 x 512, 16-cm field of view) T2-weighted fast spin-echo imaging of oblique coronal sections. The width of each rostral crus of the fornix was measured by three neuroradiologists who did not know the patients' history and surgical findings, and consensus measurements were obtained. The side with the smaller fornix was interpreted as abnormal. All 13 patients had lateralizing findings on EEG, unilateral anterior temporal lobectomy, and histologic findings of hippocampal sclerosis. RESULTS: The fornix was smaller on the side of hippocampal sclerosis in 12 (92%) of 13 patients. The percentage of asymmetry between the fornices (smallest/largest x 100) varied from 41% to 82% (mean, 68%). CONCLUSION: Our experience indicates that volume loss in the ipsilateral crus of the fornix can be seen on MR images in patients with unilateral hippocampal sclerosis. The size of the fornices should be analyzed in all patients being examined for temporal lobe epilepsy, as asymmetry in the size of the fornices may reveal the side of hippocampal sclerosis. Such knowledge can assist in the preoperative workup of patients with intractable temporal lobe epilepsy related to hippocampal sclerosis.

Extensor mechanism function after patellar tendon graft harvest for anterior cruciate ligament reconstruction.

We evaluated extensor mechanism function in 10 patients after they had arthroscopically assisted ACL reconstruction using the central third of the patellar tendon. The patients were randomly selected 12 to 24 months after reconstruction. All had rehabilitation where range of motion was initiated within the 1st postoperative week. All patients stated that they were satisfied and considered their knee to be stable. The KT-1000 maximum measurements (30 to 40 pounds) averaged an increase of 1.7 mm when compared with the opposite knee. Subjective complaints, such as anterior knee pain, grating, and weakness, were common and only 3 of 10 patients returned to all of their preinjury sports. Persistent radiographic abnormalities were common. Physical examination and functional testing also revealed persistent dysfunction of the extensor mechanism in patients with radiographic abnormalities. Isokinetic testing at 60 deg/sec showed an average quadriceps deficit of 18% compared to the normal extremity. Axial computed tomography scans revealed significant decrease in quadriceps cross-sectional area. Magnetic resonance imaging and computed tomography confirmed persistent defects at the harvest site; there was significant anterior knee scar formation in these patients. Despite achieving ligamentous stability, patients still experienced permanent weakness, functional deficits, patellar chondrosis, and pain after ACL reconstruction using the central one-third of the patellar tendon.

Computed tomography of the pancreas: negative contrast medium.

The usefulness of polyunsaturated fat, an oral negative contrast material, in outlining the stomach and duodenum in computed tomography is described. Some advantages and limitations of the contrast material are discussed.

CT detection of infected synthetic grafts: preliminary report of a new sign.

The diagnosis of infected synthetic grafts is difficult using traditional radiographic techniques. In four cases, computed tomography demonstrated small pockets of gas in the clot around the grafts, a distinctive finding for an infected prosthesis. Further experience is required to determine whether this will prove to be a reliable diagnostic sign. The gas collections in infected grafts differ from normal gas in their multiplicity and occurrence more than 10 days after surgery.

A 6 mm collimator system for the EMI CT5000/5005 whole body scanner.

A new 6 mm collimator for the EMI CT5000/5005 scanner is described. It consists of a narrower tube side and detector side collimator that can be set up in less than 5 min. The applications are primarily for the orbit and parasellar area. Future applications with the aid of new software include coronal reconstruction.