Thorsten L. Krebs

Helical computerized tomography arteriography for evaluation of live renal donors undergoing laparoscopic nephrectomy.

PURPOSE Traditionally, live renal donors are evaluated with excretory urography and renal arteriography. Helical computerized tomography (CT) arteriography offers a less invasive alternative for demonstrating necessary anatomical information before laparoscopic allograft harvest. We evaluate the accuracy of helical CT arteriography in depicting renal vascular anatomy with an emphasis on the detection of arterial and venous anomalies. MATERIALS AND METHODS Imaging studies were done on 175 patients according to a standard CT arteriography protocol with early arterial phase scanning (14 to 20-second delay), and 1 mm. axial and 3-dimensional maximum intensity projection reconstructions. Renal vascular anatomy was mapped with attention to aberrant arterial and venous anatomy. Intraoperative findings were correlated at laparoscopic donor nephrectomy. RESULTS There was overall agreement between CT arteriography and laparoscopic findings in 163 cases (93%). Supernumerary renal arteries were identified in 40 cases (23%). Sensitivity, specificity and accuracy of CT arteriography for arterial anatomy were 91, 98 and 96%, respectively. Cases with less than 2 mm. accessory arteries or early branching single vessels simulating dual arteries were misdiagnosed. Venous anomalies occurred in 11 patients (6.3%). Sensitivity, specificity and accuracy of CT arteriography for venous anatomy were 65, 100, and 97%, respectively. Misdiagnoses included early venous bifurcations and supernumerary tributary veins, which were poorly opacified. CONCLUSIONS Helical CT is highly accurate and specific for the demonstration of renal arterial anatomy. Poor opacification resulted in a lower sensitivity for venous anatomy. Overall, helical CT provides essential anatomical information, and is an alternative to standard urography and arteriography.

Cytoablative therapy with combined resection and cryosurgery for limited bilobar hepatic colorectal metastases

BACKGROUND Cryosurgery can be employed in patients with unresectable hepatic metastases when the tumor size and the number of metastases are limited. However, local recurrence can result from incomplete ablation. We proposed a trial of complete cytoablation with a combined approach of cryosurgery and hepatic resection for patients with bilobar hepatic metastases. METHODS Seven patients underwent cryosurgery alone (CRYO). Seven additional patients underwent combined resection and cryosurgery (CRYO+RES) for bilobar metastases. RESULTS In the CRYO group, 5 of 7 patients had at least one centrally located tumor. All 5 of these patients had early recurrence at the site of ablation. In the CRYO+RES group complete ablation was achieved in 7 of 7. Two (28.6%) of these patients developed local recurrence. CONCLUSION Cytoablation of hepatic metastases can be safely achieved with combined hepatic resection and cryosurgery in selected patients. Long-term survival data are necessary before advocating widespread application of this approach.

End stage renal transplant failure : Allograft appearances on CT

INTRODUCTION Failed renal allografts often are left in situ in patients who revert to chronic dialysis therapy or who undergo retransplantation. These patients may be investigated with computed tomography (CT) imaging for allograft-related or other abdominopelvic disease. This study describes the appearances of failed renal transplants on CT. METHODS A retrospective study was made of the clinical records and CT findings on 25 studies in 14 patients, 5-156 months (average, 44 months) following allograft failure. CT studies were reviewed for allograft position, size, shape, attenuation value, calcification, cyst formation, related abdominopelvic findings and the presence of other allografts. Correlation was made with clinical findings in all patients and with pathological findings in six. RESULTS Global shrinkage was noted in eight failed allografts, all of which were asymptomatic. Enlargement of two failed allografts was due to symptomatic acute infarction of the allograft in one patient and subacute haemorrhagic infarction simulating a tumour mass in another. CT attenuation values in individual allografts varied markedly due to fatty replacement, hydronephrosis, haemorrhage or dense calcification. Both a failed longstanding and a functioning more recently placed renal allograft were present in seven patients, four of whom had acute complications related to the more recently transplanted kidney. Two of six calcified allografts were mistaken for opacified bowel on CT. CONCLUSION A wide spectrum in size, shape and attenuation values may be detected in failed renal allografts by CT. These organs may be the site of acute disease despite their lack of physiological function or may be diagnostically confusing findings in patients with acute disease related to more recently transplanted organs.

Creating a digital video-based teaching file for interventional procedures using CT fluoroscopy

A computerized radiology education teaching file application, MRW (Multimedia Radiology Workstation), was produced in our department as a collaboration of faculty, fellows and a doctoral student. This inexpensive and flexible system is novice-programmable and is capable of capturing images from multiple modalities (including still and cine image) and organizing them into individual electronic teaching cases. Help and tutorial functions support the main case display functions.