Original Clinical Science
Prevalence of Incidental Findings on Abdominal Computed Tomography Angiograms on Prospective Renal Donors Nelly Tan,1 Aphinya Charoensak,2 Khobkhoon Ajwichai,1 Hans Albin Gritsch,3 Gabriel Danovitch,4 Peter Schulam,5 David S.K. Lu,1 Daniel J. Margolis,1 and Steven S. Raman1 Objective. To evaluate the prevalence of incidental findings on preoperative abdominal computed tomography angiography– computed tomography urography in asymptomatic prospective renal donors. Methods. A Health Insurance Portability and Accountability Act (HIPAA)-compliant, Institutional Review Board (IRB)-approved retrospective study of 1,597 subjects undergoing renal transplant evaluation from June 1, 2006, to March 31, 2011, was performed. Candidates underwent multiphasic multidetector computed tomography angiography–computed tomography urography for presurgical evaluation of renal vascular and parenchymal anatomy. All scans were reviewed by one of three fellowship-trained abdominal radiologists. The diagnoses were made on the basis of computed tomography characteristics of each lesion, and pathology confirmation was available for seven patients. We calculated the prevalence of each incidental finding, performed Fisher exact test or chi-square test for categorical variables between the cohort that did and did not undergo donor nephrectomy, and performed simple linear logistic regression analysis of incidental findings which predicted renal donation. Results. Of the 1,597 potential donors, 58.4% were female, and the mean age was 42.6 years (range, 18–74). One thousand one hundred ninety-five (74.9%) had a total of 2,105 incidental findings. Based on American College of Radiology Incidental Findings Committee White Paper on Managing Incidental Findings on Abdominal Computed Tomography, 17.3% had incidentalomas and 1.1% required follow-up. Majority of the incidental findings (16 of 17) were in patients who did not undergo renal donation. The prevalence of pathologically proven malignancy was 0.1% (3 of 1,597). Conclusion. Preoperative computed tomography angiography–computed tomography urography not only identifies vascular anatomy but may also help detect clinically significant unanticipated findings in an otherwise healthy population.
(Transplantation 2015;99: 1203–1207)
M
ultidetector computed tomography angiography– computed tomography urography (MDCTA-CTU) has replaced conventional angiography for assessment of renal vascular anatomy before living donor nephrectomy.1,2
Received 6 December 2013. Revision requested 24 June 2014. Accepted 4 September 2014. 1
Department of Radiology, David Geffen School of Medicine at University of California, Los Angeles CA.
2
Department of Radiology, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
3
Department of Urology, David Geffen School of Medicine at University of California, Los Angeles, CA.
4
Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA.
5
Department of Urology, Yale-New Haven Hospital, New Haven, CT.
The authors declare no funding or conflicts of interest. N.T., A.C., K.A., P.G.S., H.A.G., S.D., P.S., D.S.K.L., and S.S.R. participated in research design. N.T., A.C., K.A., P.G.S., H.A.G., S.D., P.S., S.S.R. participated in writing, N.T., A.C., K.A., P.G.S., H.A.G., S.D., D.S.K.L., D.J.M., and S.S.R. participated in performance of research. N.T. and A.C. participated in data analysis. Correspondence: Nelly Tan, MD, Department of Radiology, David Geffen School of Medicine at University of California, 757 Westwood Blvd., Los Angeles, CA 90095. ([email protected]). Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0041-1337/15/9906-1203 DOI: 10.1097/TP.0000000000000486
Transplantation
■
June 2015
■
Volume 99
■
Number 6
These studies may image the lung bases, abdomen, and pelvis and thus have the potential to detect a wide variety of clinically occult abnormalities which may affect kidney donation. Characterization of these lesions is dependent on many factors, including quality of the study and expertise of the radiologist. The characterized lesions are stratified by importance and significance to determine if they require no further workup or if they may potentially affect donor health requiring additional testing or subspecialty referral. The prevalence of incidental findings has previously been reported in studies evaluating CT colonography performed in older patients with high colon cancer risk.3–7 However, the results of these studies may not be applicable to the younger and healthier potential donor nephrectomy population. Further, many findings cannot be adequately characterized on unenhanced CT, leading to further testing. To our knowledge, there have been no reported large cohort studies reporting the overall prevalence of significant nonvascular and vascular incidental findings on contrast enhanced CT scans performed in an asymptomatic prospective donor population. Our transplant center is one of the largest in the United States and performs over 100 living donor renal transplantations per year. Potential healthy donors undergo rigorous medical and psychosocial screening before donation. All of our donor candidates are evaluated by a transplant coordinator registered nurse, nephrologist, social worker, and www.transplantjournal.com
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
1203
1204
Transplantation
■
June 2015
■
Volume 99
■
Number 6
psychiatrist. The donor team, including an independent donor advocate, advises the candidate of the risks and benefits of further evaluation and kidney donation. The candidate is advised of the options of kidney donation by a multidisciplinary team including the donor and recipient surgeons after the anatomic results and incidental findings have been evaluated. If deemed a reasonable candidate for donation, each candidate will undergo abdominal MDCTA-CTU to evaluate the potential donor’s kidneys and vascular anatomy to determine the most suitable side for nephrectomy. The primary purpose of this study was to determine the prevalence of incidental findings on preoperative MDCTA-CTU in a healthy cohort of potential renal donors on donor nephrectomy. An incidental finding, also known as an incidentaloma, may be defined as “an incidentally discovered mass or lesion, detected by CT, MRI, or other imaging modality performed for an unrelated reason”.8 RESULTS Of the 1,597 potential donors, 665 (41.6%) were men, and the mean age of the entire cohort was 42.6 years (range, 18–74). One thousand one hundred ninety-five (74.9%) had a total of 2,105 incidental findings detected on MDCTACTU (Fig. 1). Of the 1,597 potential donors, there were 702 (44.0%) who underwent kidney donation and comprised the donor subcohort. The remainder (895 (56%)) did not donate and comprised the nondonor subcohort. Incidental Findings
Incidental findings were seen in 1,195 (74.9%) patients. Seventy-three (4.5%) had incidental findings of moderate or high concern, which warranted additional workup (Fig. 1). Incidental findings were further stratified according to the American College of Radiology (ACR) Incidental Findings Committee White Paper on Managing Incidental Findings on Abdominal CT8 (Table 1). Although the prevalence of each incidental finding alone did not differ between the two subcohorts, the prevalence of incidental findings requiring further workup were significantly different between the donor and nondonor subcohorts (0.1% vs. 1.8%, P
Prevalence of Incidental Findings on Abdominal Computed Tomography Angiograms on Prospective Renal Donors Nelly Tan,1 Aphinya Charoensak,2 Khobkhoon Ajwichai,1 Hans Albin Gritsch,3 Gabriel Danovitch,4 Peter Schulam,5 David S.K. Lu,1 Daniel J. Margolis,1 and Steven S. Raman1 Objective. To evaluate the prevalence of incidental findings on preoperative abdominal computed tomography angiography– computed tomography urography in asymptomatic prospective renal donors. Methods. A Health Insurance Portability and Accountability Act (HIPAA)-compliant, Institutional Review Board (IRB)-approved retrospective study of 1,597 subjects undergoing renal transplant evaluation from June 1, 2006, to March 31, 2011, was performed. Candidates underwent multiphasic multidetector computed tomography angiography–computed tomography urography for presurgical evaluation of renal vascular and parenchymal anatomy. All scans were reviewed by one of three fellowship-trained abdominal radiologists. The diagnoses were made on the basis of computed tomography characteristics of each lesion, and pathology confirmation was available for seven patients. We calculated the prevalence of each incidental finding, performed Fisher exact test or chi-square test for categorical variables between the cohort that did and did not undergo donor nephrectomy, and performed simple linear logistic regression analysis of incidental findings which predicted renal donation. Results. Of the 1,597 potential donors, 58.4% were female, and the mean age was 42.6 years (range, 18–74). One thousand one hundred ninety-five (74.9%) had a total of 2,105 incidental findings. Based on American College of Radiology Incidental Findings Committee White Paper on Managing Incidental Findings on Abdominal Computed Tomography, 17.3% had incidentalomas and 1.1% required follow-up. Majority of the incidental findings (16 of 17) were in patients who did not undergo renal donation. The prevalence of pathologically proven malignancy was 0.1% (3 of 1,597). Conclusion. Preoperative computed tomography angiography–computed tomography urography not only identifies vascular anatomy but may also help detect clinically significant unanticipated findings in an otherwise healthy population.
(Transplantation 2015;99: 1203–1207)
M
ultidetector computed tomography angiography– computed tomography urography (MDCTA-CTU) has replaced conventional angiography for assessment of renal vascular anatomy before living donor nephrectomy.1,2
Received 6 December 2013. Revision requested 24 June 2014. Accepted 4 September 2014. 1
Department of Radiology, David Geffen School of Medicine at University of California, Los Angeles CA.
2
Department of Radiology, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
3
Department of Urology, David Geffen School of Medicine at University of California, Los Angeles, CA.
4
Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA.
5
Department of Urology, Yale-New Haven Hospital, New Haven, CT.
The authors declare no funding or conflicts of interest. N.T., A.C., K.A., P.G.S., H.A.G., S.D., P.S., D.S.K.L., and S.S.R. participated in research design. N.T., A.C., K.A., P.G.S., H.A.G., S.D., P.S., S.S.R. participated in writing, N.T., A.C., K.A., P.G.S., H.A.G., S.D., D.S.K.L., D.J.M., and S.S.R. participated in performance of research. N.T. and A.C. participated in data analysis. Correspondence: Nelly Tan, MD, Department of Radiology, David Geffen School of Medicine at University of California, 757 Westwood Blvd., Los Angeles, CA 90095. ([email protected]). Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0041-1337/15/9906-1203 DOI: 10.1097/TP.0000000000000486
Transplantation
■
June 2015
■
Volume 99
■
Number 6
These studies may image the lung bases, abdomen, and pelvis and thus have the potential to detect a wide variety of clinically occult abnormalities which may affect kidney donation. Characterization of these lesions is dependent on many factors, including quality of the study and expertise of the radiologist. The characterized lesions are stratified by importance and significance to determine if they require no further workup or if they may potentially affect donor health requiring additional testing or subspecialty referral. The prevalence of incidental findings has previously been reported in studies evaluating CT colonography performed in older patients with high colon cancer risk.3–7 However, the results of these studies may not be applicable to the younger and healthier potential donor nephrectomy population. Further, many findings cannot be adequately characterized on unenhanced CT, leading to further testing. To our knowledge, there have been no reported large cohort studies reporting the overall prevalence of significant nonvascular and vascular incidental findings on contrast enhanced CT scans performed in an asymptomatic prospective donor population. Our transplant center is one of the largest in the United States and performs over 100 living donor renal transplantations per year. Potential healthy donors undergo rigorous medical and psychosocial screening before donation. All of our donor candidates are evaluated by a transplant coordinator registered nurse, nephrologist, social worker, and www.transplantjournal.com
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
1203
1204
Transplantation
■
June 2015
■
Volume 99
■
Number 6
psychiatrist. The donor team, including an independent donor advocate, advises the candidate of the risks and benefits of further evaluation and kidney donation. The candidate is advised of the options of kidney donation by a multidisciplinary team including the donor and recipient surgeons after the anatomic results and incidental findings have been evaluated. If deemed a reasonable candidate for donation, each candidate will undergo abdominal MDCTA-CTU to evaluate the potential donor’s kidneys and vascular anatomy to determine the most suitable side for nephrectomy. The primary purpose of this study was to determine the prevalence of incidental findings on preoperative MDCTA-CTU in a healthy cohort of potential renal donors on donor nephrectomy. An incidental finding, also known as an incidentaloma, may be defined as “an incidentally discovered mass or lesion, detected by CT, MRI, or other imaging modality performed for an unrelated reason”.8 RESULTS Of the 1,597 potential donors, 665 (41.6%) were men, and the mean age of the entire cohort was 42.6 years (range, 18–74). One thousand one hundred ninety-five (74.9%) had a total of 2,105 incidental findings detected on MDCTACTU (Fig. 1). Of the 1,597 potential donors, there were 702 (44.0%) who underwent kidney donation and comprised the donor subcohort. The remainder (895 (56%)) did not donate and comprised the nondonor subcohort. Incidental Findings
Incidental findings were seen in 1,195 (74.9%) patients. Seventy-three (4.5%) had incidental findings of moderate or high concern, which warranted additional workup (Fig. 1). Incidental findings were further stratified according to the American College of Radiology (ACR) Incidental Findings Committee White Paper on Managing Incidental Findings on Abdominal CT8 (Table 1). Although the prevalence of each incidental finding alone did not differ between the two subcohorts, the prevalence of incidental findings requiring further workup were significantly different between the donor and nondonor subcohorts (0.1% vs. 1.8%, P
