Use of Computed Tomography Renal Angiography for Screening Feline Renal Transplant Donors

Abstract

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.

Is there a difference between the right and left kidney? A macroscopic approach in Brazilian Shorthair Cat

“…Arterial anastomosis is most successful if there is a single renal artery with a length prior to branching of at least 0.5cm. If the vascular pedicle has more than one vein, the vein with the longest length and largest diameter is reserved for the anastomosis (Bouma et al, 2003).…”

Time‐resolved Renal Contrast‐enhanced Mra in Normal Dogs

“…Application of the method to pretreatment imaging of animals with various renal conditions such as neoplasia or vascular malformation associated with hematuria is also envisioned when surgery or embolization are contemplated. In comparing with our previous experience with contrast‐enhanced computed tomography angiography, 1–7 we believe that CE‐MRA is an interesting alternative in that it is faster, potentially safer, and reconstruction/visualization is much easier than with contrast‐enhanced computed tomography angiography. The approach used herein to image the renal vessels can also be applied to other vascular territories.…”

“…The acquisition time for each dorsal slab was short enough to prescribe several successive acquisitions of the same volume within one breath‐hold. Based on our previous experience with contrast‐enhanced computed tomography angiography, 1,2 it was estimated that if acquisition was begun at the time of injection of gadolinium, the first pass of contrast medium within the renal arteries would occur during either phase 1 or 2, and the first pass through the renal veins during phase 2 or 3, depending on scanning time per phase. We confirmed that hypothesis although we did not observe a pure arterial enhancement in dog 5, but rather overlapping between the arterial and venous enhancements.…”

A Carrel patch technique for renal transplantation in cats

“…A study in cats reported a 92% agreement between CTA and surgical anatomy of the left renal vasculature . When IVU was used to screen donors, a relatively high incidence (∼10%) of failure to detect unacceptable renal vascular conformation resulted in such detection only at the time of surgery . The low incidence of bilateral multiple arteries, additional cost, and anesthetic considerations may prompt surgeons to refrain from obtaining a preoperative CTA and IVU.…”