Utility of CT angiography for evaluation of living kidney donors

Evaluation of Renal Arteries of 286 Living Donors by Multidetector Computed Tomography Angiography: A Single-Center Study

OBJECTIVES

In living renal donors, digital subtraction angiography and intravenous pyelogram techniques developing traditional evaluation before transplant have started to give place to more modern and less-invasive methods such as multidetector computerized tomography angiography, and magnetic resonance angiography via the developments in the imaging technology. We aimed to evaluate the renal arteries of living-renal donors by multidetector computerized tomography angiography and to compare the findings with the surgical results.

MATERIALS AND METHODS

In our renal transplant center, 286 living-donor candidates to whom multi-detector computerized tomography angiography was applied, were evaluated retrospectively and the findings were compared with the surgical operation notes.

RESULTS

In 180 of 286 living donor candidates to whom computerized tomography angiography was applied, bilateral single renal artery was deter-mined. In 79 renal donor candidates, unilateral multiple renal artery; and in 27 renal donor candidates, bilateral multiple renal artery were found. In 58 renal donor candidates, at least 1 polar artery was specified; in 32 renal donor candidates, a unilateral single renal artery; in 10 renal donor candidates, a bilateral double renal artery was determined. When computerized tomography angiography and operative notes were compared, we observed that the findings in 280 donor candidates were the same. In 6 renal donor candidates, differences in the findings were present. Our accuracy rate was 97% and according to the operative notes, our sensitivity and specificity ratios in determining multiple renal arteries were calculated as 98% and 95%.

CONCLUSIONS

Multidetector computerized tomography angiography can be used rapidly and efficiently in living-donor renal candidates with high specificity and sensitivity ratios.

Multidetector CT angiography in live donor renal transplantation: experience from 156 consecutive cases at a single centre

The performance of multidetector computed tomography (CT) angiography was assessed in the pre-operative evaluation of live renal donors. Between July 1998 and March 2006, 156 consecutive patients underwent open donor nephrectomy following pre-operative multidetector CT angiography (MDCTA). Operative notes were compared with radiological reports and discrepancies identified. MDCTA missed five of 28 accessory arteries (four visible with hindsight), accuracy of 96%. Of 30 early-branching renal arteries, eight were missed (all visible with hindsight), accuracy 95%. MDCTA missed only one of 13 venous anomalies (accuracy 97%) and also missed the only duplicated collecting system: both were undetectable with hindsight. Following modifications to image acquisition and interpretation sensitivity, negative-predictive value and accuracy were significantly increased. The results were compared with pooled data from published studies of live donor imaging. This study and previous studies of MDCTA had improved sensitivity for arterial and venous anomalies over single detector CT angiography and MR angiography. We conclude that multidetector CT angiography is an accurate modality in the pre-operative evaluation of live renal donors. Regular communication between the transplant surgeon and the radiologist is paramount to improve reporting of surgically relevant anatomy. Mechanisms should exist for auditing and improving pre-operative imaging in any live donor programme.

Donor Nephrectomy in the Era of Hand-Assisted Laparoscopic Urologic Surgery

Living-donor nephrectomy has traditionally been performed through a flank incision with or without rib resection or by an anterior extraperitoneal incision, both of which reduce the willingness of potential donors to undergo the procedure. The first successful human laparoscopic donor nephrectomy was reported in 1995. In order to reduce warm ischemia and operative time and to make the operation safer and easier, some laparoscopic surgeons have used hand assistance. The authors describe their technique for this operation and review the results.

USE OF COMPUTED TOMOGRAPHY RENAL ANGIOGRAPHY FOR SCREENING FELINE RENAL TRANSPLANT DONORS

Preoperative knowledge of the renal vascular anatomy is important for selection of the appropriate feline renal donor. Intravenous urograms (IVUs) have been performed routinely to screen potential donors at the Veterinary Hospital of the University of Pennsylvania (VHUP), but the vascular phase views lack sufficient detail of the renal vascular anatomy. Computed tomography angiography (CTA), which requires a helical computed tomography (CT) scanner, has been found to provide superior renal vascular anatomic information of prospective human renal donors. The specific aims of this study were as follows: 1) develop the CTA technique for the feline patient; and 2) obtain preliminary information on feline renal vessel anatomy in potential renal donors. Ten healthy, potential feline renal donors were anesthetized and imaged using a third-generation helical CT scanner. The time delay between i.v. contrast medium injection and image acquisition, and other parameters of slice collimation, slice interval, pitch, exposure settings, and reconstruction algorithms were varied to maximize contrast medium opacification of the renal vascular anatomy. Optimal CTA acquisition parameters were determined to be: 1) 10-sec delay post-i.v. bolus of iodinated contrast medium; 2) two serially acquired (corresponding to arterial and venous phases) helical scans through the renal vasculature; 3) pitch of 2 (4 mm/sec patient translation, 2 mm slice collimation); and 4) 120-kVp, 160-mA, and 1-sec exposure settings. Retrospective reconstructed CTA transverse images obtained at a 2-mm slice width and a 1-mm slice interval in combination with two-dimensional reformatted images and three-dimensional reconstructed images were qualitatively evaluated for vascular anatomy; vascular anatomy was confirmed at surgery. Four cats had single renal arteries and veins bilaterally; four cats had double renal veins. One cat had a small accessory artery supplying the caudal pole of the left kidney. One cat had a left renal artery originating from the aorta at a 90 degrees angle with the cranial mesenteric artery. CTA of the feline renal vascular anatomy is feasible, and reconstruction techniques provide excellent anatomic vascular detail. CTA is now used routinely at VHUP to screen all potential feline renal donors.

Live donor renal transplants using kidneys with arteriographic evidence of mild renovascular disease

The objective of the study was to determine whether using a living donor kidney with arteriographic evidence of renovascular disease affects the outcome of the recipient's transplanted graft. Twenty-eight patients who had unilateral renovascular abnormalities on conventional angiography underwent donor nephrectomy of the ipsilateral kidney. Results in the recipients who received these kidneys were reviewed. Comparison was made to a control group of living donor renal transplant recipients who were matched for donor, recipient age. Graft survival, patient survival, serum creatinine for all 28 recipients were evaluated. All 28 donors underwent a successful donor nephrectomy. Recipient graft survival was 96% at 1 yr, 92% at 3 yr, 71% at 5 yr, 62% at 10 yr. Mean serum creatinine values at 1 month, 1 yr, 3 yr were 1.5, 1.5, 1.6, respectively. Similar results were observed in the control group. We conclude that renal transplantation utilizing kidneys with arteriographic evidence of renovascular disease results in excellent short, long-term renal allograft survival.

Three-dimensional CT of the genitourinary tract

The applications of three-dimensional (3D) CT techniques encompass a spectrum from calculus disease to preoperative planning. With proper selection of display windows and levels, accurate measurement of stone size can be achieved, along with volumetric information. A CT scan with reconstruction may help guide the direction of an endopyelotomy incision away from crossing vessels. The benefits of 3D CT in the evaluation of living renal donors include lower cost and decreased patient morbidity. In renal allograft recipients and other patients, the study may be used to investigate hypertension. Also, 3D CT is invaluable in planning nephron-sparing surgery for renal masses. The ultimate role of this modality rests in the hands of clinicians who can benefit from them and the radiologists who must provide the high-quality images and the interpretive expertise.

Laparoscopic living donor nephrectomy: advantages of the hand-assisted method

INTRODUCTION

The laparoscopic technique for living donor nephrectomy is a technically difficult procedure that has not yet gained widespread acceptance in the transplant community. The procedure may be more acceptable if alterations to the technique made it easier to perform and decreased operative times.

METHODS

In August 1998, we altered the laparoscopic procedure to include the use of a device allowing hand assistance. Subsequently, all living donor nephrectomies have been done using the hand-assisted method. In this article, the results of 10 cases performed using the original laparoscopic technique are compared with the results of 12 cases using the hand-assisted technique, and a brief description of modifications to the original technique is given.

RESULTS

No patients where turned down as living donors, and no contraindications to the pure or hand-assisted laparoscopic techniques where found. The hand-assisted technique significantly reduced the operative time (2.02+/-0.44 vs. 3.12+/-0.36 hr, P<0.05) and the warm ischemic time (1.23+/-0.54 vs. 3.91+/-0.53 min, P<0.05). The length of stay and recovery time to normal activities were not different between the pure laparoscopic and hand-assisted groups.

CONCLUSION

The advantages of the hand-assisted technique include the ability to use tactile sense to facilitate dissection, retraction, and exposure. In addition, the final stages of vascular stapling and kidney removal are more sure and rapid. The modifications of the laparoscopic technique presented here provide measurable and subjective improvements to laparoscopic living donor nephrectomy. The hand-assisted method of laparoscopic nephrectomy may make the operation available to more transplant centers.