MDCT angiography of living laparoscopic renal donors

Standardized Reporting on the Preoperative CT Assessment of Potential Living Renal Transplant Donors: Can We Create a Universal Report Standard to Meet the Needs of Transplant Urologists?

Purpose: Determine whether standardized template reporting for the preoperative assessment of potential living renal transplant donors improves the comprehensiveness of radiology reports to meet the needs of urologists performing renal transplants. Methods: Urologist and radiologist stakeholders from renal transplant centres in our province ratified a standardized reporting template for evaluation of potential renal donors. Three centres (A, B, and C) were designated "intervention" groups. Centre D was the control group, given employment of a site-specific standardized template prior to study commencement. Up to 100 consecutive CT scan reports per centre, pre- and post-implementation of standardized reporting, were evaluated for reporting specific outcome measures. Results: At baseline, all intervention groups demonstrated poor reporting of urologist-desired outcome measures. Centre A discussed 5/13 variables (38%), Centre B discussed 6/13 variables (46%), and Centre C only discussed 1/13 variables (8%) with ≥90% reliability. The control group exhibited consistent reporting, with 11/13 variables (85%) reported at ≥90% reliability. All institutions in the intervention group exhibited excellent compliance to structured reporting post-template implementation (Centres A = 95%, B = 100%, and C = 77%, respectively). Additionally, all intervention centres demonstrated a significant improvement in the comprehensiveness of reports post-template implementation, with statistically significant increases in the reporting of all variables under-reported at baseline (P > .01). Conclusion: Standardized templates across our province for CT scans of potential renal donors promote completeness of reports. Radiologists can reliably provide our surgical colleagues with needed preoperative anatomy and incidental findings, helping to determine suitable transplant donors and reduce potential complications associated with organ retrieval.

Impact of Incidental Findings During the Evaluation of Live Kidney Donors on Post-Transplant Outcomes: A Single Center Analysis

BACKGROUND

A careful assessment of a living donor is mandatory to minimize the short- and long-term risk related to kidney donation. In this study, we evaluated the incidence of incidental findings (IFs) in a large population of potential living kidney donors. Moreover, this study evaluated if the presence of IFs could influence the chance of living kidney donation and post-transplant outcomes.

METHODS

One hundred and sixty consecutive potential prospective living kidney transplant donors, who underwent a multidetector computed tomography angiography (MDCTA), were included in the study. An IF was defined as an incidentally discovered mass or lesion, detected by computed tomography angiography during the imaging evaluation of potential living donors. Clinical outcomes of living donors with IF were compared with those without IF.

RESULTS

In 10 patients (6.2%) an incidental finding was detected at MDCTA assessment. Among the 10 patients presenting with an IF, 7 patients (4.3%) were excluded from the living donation: 2 patients with an adrenal lesion, 3 patients with cancer, and 2 patients with a large (>8 cm) renal cyst. Graft and patient survival of kidney transplant recipients of donors with IFs were not significantly different to those receiving a kidney from living donors without IFs.

CONCLUSIONS

Incidental findings are frequently discovered during living kidney donor evaluation. Whereas most are asymptomatic or not clinically relevant, predonation screening could identify potentially life-threatening diseases at an earlier stage, allowing for a more radical treatment.

Prevalence of Incidental Findings on Multidetector Computed Tomography in Potential Nephrectomy Donors: A Prospective Observational Study

OBJECTIVES

Prospective renal donors are a select population of healthy individuals who have been thoroughly screened for significant comorbidities before they undergo multidetector computed tomography. Our aim was to determine the prevalence of incidental findings on preoperative multidetector computed tomography in a healthy cohort of potential living donors for kidney transplant.

MATERIALS AND METHODS

A prospective study was performed of prospective living kidney transplant donors at a national kidney transplant center. Study inclusion criteria were all potential kidney donors who underwent multidetector computed tomography during the living-donor assessment process over a 5-year period (January 2012 to 2017).

RESULTS

Our cohort included 375 potential living donors who had multidetector computed tomography; mean age was 44.33 years (range, 21-71.5 y). In total, there were 228 incidental findings identified in 158 individuals. Of the 375 potential donors, 193 (51%) proceeded to living donor nephrectomy. On multidetector computed tomography, 97 incidental findings were identified in the donor cohort versus 131 in the cohort that did not proceed to donation. Bosniak 1 renal cysts were the most common incidental finding (n = 46) followed by liver cysts < 1.5 cm (n = 42) and urinary tract calculi (n = 21). There was 1 incidentally detected pathologically proven malignancy.

CONCLUSIONS

A variety of incidentally detected lesions of moderate to high importance were detected in this healthy donor cohort. Individuals undergoing assessment with multidetector computed tomography for living donor nephrectomy should be counseled on medical, financial, and psychological implications of incidentally detected lesions during the kidney transplant evaluation process.

Assessment of Potential Live Kidney Donors and Computed Tomographic Renal Angiograms at Christchurch Hospital

Aims. To examine the outcome of potential live kidney donors (PLKD) assessment program at Christchurch Hospital and, also, to review findings of Computed Tomographic (CT) renal angiograms that led to exclusion in the surgical assessment. Methods. Clinical data was obtained from the database of kidney transplants, Proton. Radiological investigations were reviewed using the hospital database, Éclair. The transplant coordinator was interviewed to clarify information about PLKD who did not proceed to surgery, and a consultant radiologist was interviewed to explain unfavorable findings on CT renal angiograms. Results. 162 PLKD were identified during the period January 04–June 08. Of those, 65 (40%) proceeded to have nephrectomy, 15 were accepted and planned to proceed to surgery, 13 were awaiting further assessment, and 69 (42.5%) did not proceed to nephrectomy. Of the 162 PLKD, 142 (88%) were directed donors. The proportion of altruistic PLKD who opted out was significantly higher than that of directed PLKD (45% versus 7%, P = 0.00004). Conclusions. This audit demonstrated a positive experience of live kidney donation at Christchurch Hospital. CT renal angiogram can potentially detect incidental or controversial pathologies in the kidney and the surrounding structures. Altruistic donation remains controversial with higher rates of opting out.

MDCT evaluation of potential living renal donor, prior to laparoscopic donor nephrectomy: What the transplant surgeon wants to know?

As Laparoscopic Donor Nephrectomy (LDN) offers several advantages for the donor such as lesser post-operative pain, fewer cosmetic concerns and faster recovery time, there is growing global trend towards LDN as compared to open nephrectomy. Comprehensive pre-LDN donor evaluation includes assessment of renal morphology including pelvi-calyceal and vascular system. Apart from donor selection, evaluation of the regional anatomy allows precise surgical planning. Due to limited visualization during laparoscopic renal harvesting, detailed pre-transplant evaluation of regional anatomy, including the renal venous anatomy is of utmost importance. MDCT is the modality of choice for pre-LDN evaluation of potential renal donors. Apart from appropriate scan protocol and post-processing methods, detailed understanding of surgical techniques is essential for the Radiologist for accurate image interpretation during pre-LDN MDCT evaluation of potential renal donors. This review article describes MDCT evaluation of potential living renal donor, prior to LDN with emphasis on scan protocol, post-processing methods and image interpretation. The article laid special emphasis on surgical perspectives of pre-LDN MDCT evaluation and addresses important points which transplant surgeons want to know.

Multidetector computed tomographic angiography evaluation of micropig major systemic vessels for xenotransplantation

Due primarily to the increasing shortage of allogeneic donor organs, xenotransplantation has become the focus of a growing field of research. Currently, micropigs are the most suitable donor animal for humans. However, no standard method has been developed to evaluate the systemic vascular anatomy of micropigs and standard reference values to aid in the selection of normal healthy animals as potential organ donors are lacking. Using 64-channel multidetector row computed tomographic angiography (MDCTA), we evaluated morphological features of the major systemic vessels in micropigs and compared our results to published human data. The main vasculature of the animals was similar to that of humans, except for the iliac arterial system. However, diameters of the major systemic vessels were significantly different between micropigs and humans. Specifically, the diameter of the aortic arch, abdominal aorta, external iliac artery, and femoral artery, were measured as 1.50 ± 0.07 cm, 0.85 ± 0.06 cm, 0.52 ± 0.05 cm, and 0.48 ± 0.05 cm, respectively, in the micropigs. This MDCTA data for micropig major systemic vessels can be used as standard reference values for xenotransplantation studies. The use of 64-channel MDCTA enables accurate evaluation of the major systemic vasculature in micropigs.

Three-dimensional computed tomographic angiography to predict weight and volume of deep inferior epigastric artery perforator flap for breast reconstruction

BACKGROUND

Three-dimensional computed tomographic angiography (3D CTA) can be used preoperatively to evaluate the course and caliber of perforating blood vessels for abdominal free-flap breast reconstruction. For postmastectomy breast reconstruction, many women inquire whether the abdominal tissue volume will match that of the breast to be removed. Therefore, our goal was to estimate preoperative volume and weight of the proposed flap and compare them with the actual volume and weight to determine if diagnostic imaging can accurately identify the amount of tissue that could potentially to be harvested.

METHODS

Preoperative 3D CTA was performed in 15 patients, who underwent breast reconstruction using the deep inferior epigastric artery perforator flap. Before each angiogram, stereotactic fiducials were placed on the planned flap outline. The radiologist reviewed each preoperative angiogram to estimate the volume, and thus, weight of the flap. These estimated weights were compared with the actual intraoperative weights.

RESULTS

The average estimated weight was 99.7% of the actual weight. The interquartile range (25th to 75th percentile), which represents the "middle half" of the patients, was 91-109%, indicating that half of the patients had an estimated weight within 9% of the actual weight; however, there was a large range (70-133%).

CONCLUSION

3D CTA with stereotactic fiducials allows surgeons to adequately estimate abdominal flap volume before surgery, potentially giving guidance in the amount of tissue that can be harvested from a patient's lower abdomen.

Classification schema for anatomic variations of the inferior epigastric vasculature evaluated by abdominal CT angiograms for breast reconstruction

BACKGROUND

Many studies demonstrate direct patient benefits from use of preoperative computed tomography angiograms (CTA) for abdominal tissue-based breast reconstruction. We present a novel classification schema to translate imaging results into further clinical relevance.

METHODS

Each hemiabdomen CTA was classified into a schema that addressed findings of expected anatomy, anatomy that necessitates a change in operative technique and anatomy that suggests less morbid procedures may be considered.

RESULTS

Eighty-six patients (172 hemiabdomens) were available for study. Of the reconstructions performed in this time period, 40 (47%) were bilateral and 46 (53%) unilateral. Based on perforator size and location, relative perimuscular anatomy, and continuity of vessels, five categories were defined: type I "Traditional" anatomy (n = 150, 87%), type II "Highly Favorable" anatomy (n = 11, 6.4%), type III "Altered-Superiorly Translocated" anatomy (n = 9, 5.2%), type IV "Superficial Dominant" anatomy (n = 26, 15%), and type V "Hostile" anatomy (n = 4, 2.3%). The additive total is greater than 100%, because vessels may fall into more than one category.

DISCUSSION

In providing the microsurgeon with a preoperative vascular map that has the potential to influence the preoperative, operative, and postoperative course, abdominal CTAs should be considered a worthy adjunct to the diagnostic armamentarium of the reconstructive surgeon. These classifications and their clinical impacts become even more important in centers performing increasing numbers of bilateral reconstructions. We believe that our simple schema can facilitate effective use of this powerful tool, aiding in overall care of the breast reconstruction patient.

Role of multidetector-row computed tomography in evaluation of living renal donors

OBJECTIVES

To assess the value of multidetector-row computed tomography (MDCT) in evaluation of the anatomy of living kidney donors and to reveal the prevalence of renal vascular variations in a Chinese population.

PATIENTS AND METHODS

One hundred four potential donors underwent MDCT, and the data sets were postprocessed for reformatted images using maximum intensity projection, a volume-rendering technique, and multiplanar re-formation. Nephrectomy was performed in 97 donors, which enabled correlation of MDCT evaluation with the actual anatomy at surgery as the standard of reference.

RESULTS

The MDCT images accurately demonstrated the anatomical structure of the main renal arteries and veins and the upper part of the ureters. The prevalence of accessory arteries was 41.7% (43 of 103), and of early branching was 12.6% (13 of 103). Compared with findings during surgery, the detection rate of accessory arteries on MDCT images was 91.3% (21 of 23), of larger accessory arteries (>1.5 mm in diameter) was 100%, and of early branching was 100%.

CONCLUSION

Multidetector-row computed tomography is helpful in accurately evaluating the renal anatomy of potential donors, thus facilitating planning of surgery.

CT angiography of the renal circulation

Although catheter angiography remains the accepted gold standard for imaging of the renal vascular system, rapid progress in cross-sectional imaging techniques has caused a paradigm shift in many diagnostic algorithms toward noninvasive techniques such as computed tomographic angiography (CTA). CTA's cross-sectional imaging techniques provide an opportunity for comprehensive renal investigation that would be impossible with angiography alone. While other competing noninvasive technologies such as ultrasound and magnetic resonance angiography can be used successfully in renal imaging, the benefits of CTA are substantial, including high spatial and temporal resolution, widespread availability, implantable device compatibility, and easy technical reproducibility. This article describes the technical considerations relevant to CTA of the renal vascular system, postprocessing algorithms for volumetric data, and numerous specific applications.

Semiautomated segmentation of kidney from high-resolution multidetector computed tomography images using a graph-cuts technique

OBJECTIVES

To develop a semiautomated segmentation method based on a graph-cuts technique from multidetector computed tomography images for kidney segmentation and to evaluate and compare it with the conventional manual delineation segmentation method.

MATERIALS AND METHODS

We have developed a semiautomated segmentation method that is based on a graph-cuts technique with enhanced features including automated seed growing. Multidetector computed tomography images were obtained from 15 consecutive patients who were being evaluated as possible living donors for kidney transplant. Two observers independently performed the segmentation of the kidney from the multidetector computed tomography images using the manual and semiautomated methods. The efficiency of the 2 methods were measured by segmentation processing times and then compared. The interobserver and method reproducibility was determined by Dice similarity coefficient (DSC), which measures how closely 2 segmented volumes overlap geometrically and the coefficient of variation of volume measurements.

RESULTS

The mean segmentation processing time was (manual vs semiautomated, P < 0.001) 96.8 +/- 13.6 vs 13.7 +/- 3.5 minutes for observer 1 and 44.3 +/- 4.7 vs 16.2 +/- 5.1 minutes for observer 2. The mean interobserver reproducibility was (manual vs semiautomated, P < 0.001) 93.6 +/- 1.6% vs 97.3 +/- 0.9% for DSC and 5.3 +/- 2.6% vs 2.2 +/- 1.3% for coefficient of variation, indicating higher interobserver reproducibility with the semiautomated than manual method. The agreement between the 2 segmentation methods was high (mean intermethod DSC 95.8 +/- 1.0% and 94.9 +/- 0.8%) for both observers.

CONCLUSIONS

The semiautomated method was significantly more efficient and reproducible than the manual delineation method for segmentation of kidney from MDCT images.

Single-phase 16-slice multidetector computed tomographic angiography in the evaluation of the venous system in potential laparoscopic renal donors

OBJECTIVE

Our objective was to assess the efficacy of single-arterial-phase, 16-slice multidetector computed tomographic (16-MDCT) angiography in the evaluation of both the renal arterial and venous systems in prospective renal donors with surgical (laparoscopic) correlation.

METHODS

Fifty-one consecutive renal donors (age range, 20-62 years; 12 men and 39 women) underwent 16-MDCT angiography followed by laparoscopic donor nephrectomy. Approval from institutional review board was obtained with waiver of consent. The arterial-phase image data set was reviewed independently by 2 abdominal radiologists for the number of renal arteries and veins, anomalies, and degree of opacification of the renal veins. Computed tomographic angiography results were compared with the surgical findings. Interobserver agreement was assessed using kappa statistics.

RESULTS

The sensitivity, specificity, and accuracy for identifying the number of renal veins in the arterial phase on 16-MDCT angiography were 96.3%, 96.07%, and 96.2% for reviewer 1 and 94.44%, 94.11%, and 94.3% for reviewer 2, respectively. Both reviewers correctly identified all venous anomalies and had substantial interobserver agreement (kappa coefficient = 0.68).

CONCLUSIONS

A single-arterial-phase image data set is sufficient for evaluation of both the renal arterial and venous anatomy in potential renal donors before laparoscopic nephrectomy. Venous-phase acquisition is not necessary, thereby substantially reducing the radiation burden on the donor.

Diagnostic accuracy of a volume-rendered computed tomography movie and other computed tomography-based imaging methods in assessment of renal vascular anatomy for laparoscopic donor nephrectomy

To evaluate the diagnostic accuracy of computed tomography (CT)-based imaging methods for assessing renal vascular anatomy, imaging studies, including standard axial CT, three-dimensional volume-rendered CT (3DVR-CT), and a 3DVR-CT movie, were performed on 30 patients who underwent laparoscopic donor nephrectomy (10 right side, 20 left side) for predicting the location of the renal arteries and renal, adrenal, gonadal, and lumbar veins. These findings were compared with videos obtained during the operation. Two of 37 renal arteries observed intraoperatively were missed by standard axial CT and 3DVR-CT, whereas all arteries were identified by the 3DVR-CT movie. Two of 36 renal veins were missed by standard axial CT and 3DVR-CT, whereas 1 was missed by the 3DVR-CT movie. In 20 left renal hilar anatomical structures, 20 adrenal, 20 gonadal, and 22 lumbar veins were observed during the operation. Preoperatively, the standard axial CT, 3DVR-CT, and 3DVR-CT movie detected 11, 19, and 20 adrenal veins; 13, 14, and 19 gonadal veins; and 6, 11, and 15 lumbar veins, respectively. Overall, of 135 renal vascular structures, the standard axial CT, 3DVR-CT, and 3DVR-CT movie accurately detected 99 (73.3%), 113 (83.7%), and 126 (93.3%) vessels, respectively, which indicated that the 3DVR-CT movie demonstrated a significantly higher detection rate than other CT-based imaging methods (P < 0.05). The 3DVR-CT movie accurately provides essential information about the renal vascular anatomy before laparoscopic donor nephrectomy.

3D CT angiography of abdominal wall vascular perforators to plan DIEAP flaps

PURPOSE

Since the first report of TRAM flap reconstruction, there have been numerous studies to reduce complications of elective breast reconstruction. Current methods of preoperative perforator localization can be time-consuming, inaccurate, and imprecise. Thus, we sought to evaluate ultra-high resolution 3D CT angiography for the preoperative mapping of DIEAP flap perforating vessels.

METHODS

We reviewed all perforator-based breast reconstructions performed over a 5-month period. Candidates for DIEAP flap reconstruction were sent for a focused CT scan of the abdominal wall, using the 64 slice multi-detector CT scanner.

RESULTS

This article presents our first 23 flaps in 17 patients with preoperative ultra-high resolution 3D CT angiography. The reconstruction plan changed in three patients (18%). There was one take-back for venous congestion, but no partial or total flap loss.

CONCLUSIONS

Preoperative perforator flap planning for breast reconstruction utilizing 3D CT angiogram is safe, easy to read, and can change the operative plan.

Magnetic resonance angiography of chest and abdomen at 3 T

During the past decade, contrast-enhanced magnetic resonance angiography (CE-MRA) has been proven to be a powerful tool to visualize the thoracoabdominal vasculature and, consequently, has become a widely accepted noninvasive imaging modality. With the more recent introduction of high-field whole-body magnetic resonance scanners, a further improvement of diagnostic accuracy can be expected. General considerations for performing high-resolution CE-MRA at higher field strength include the benefits of higher signal-to-noise ratio and an improved contrast between vascular and background tissues. Although there are many positive attributes for performing CE-MRA at 3 T, there are also some tradeoffs, such as static magnetic field inhomogeneity and increase in specific absorption rate. This review describes the main technical innovations of advanced CE-MRA techniques at 3 T, illustrated by characteristic cases.

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.