Friedrich-Carl von Rundstedt1, Jason M Scovell2, Shelly X Bian3, Dominic Lee4, Wesley A Mayer2, Richard E Link5. 1. Scott Department of Urology, Baylor College of Medicine, Houston, TX; Department of Urology, Jena University Hospital, Friedrich-Schiller University, Jena, Germany. 2. Scott Department of Urology, Baylor College of Medicine, Houston, TX. 3. Scott Department of Urology, Baylor College of Medicine, Houston, TX; Department of Radiation Oncology, Keck School of Medicine, University of Southern California, Los Angeles, CA. 4. Scott Department of Urology, Baylor College of Medicine, Houston, TX; Department of Urology, St. George Hospital, Kogarah, New South Wales, Australia. 5. Scott Department of Urology, Baylor College of Medicine, Houston, TX. Electronic address: link@bcm.edu.
Abstract
OBJECTIVE: To increase the diagnostic sensitivity of standard MAG3 diuretic renal scans for ureteropelvic junction obstruction (UPJO) by exploring the utility of an alternative measurement P40, the percentage of maximal tracer counts present at 40 minutes. MATERIALS AND METHODS: Patients with strong clinical and anatomic evidence for UPJO may have a normal T1/2, making definitive diagnosis difficult. We reviewed the charts of 142 consecutive patients who underwent successful laparoscopic or robotic-assisted laparoscopic pyeloplasty for UPJO between 2005 and 2015. Both pre- and postoperative renal scan images were available for 37 symptomatic patients with primary unilateral UPJO and 2 kidneys. We defined P40 as the percentage of maximal tracer counts present at 40 minutes. We identified the upper limit of normal (97.5th percentile, +2SD) for P40 using the preoperative renal scans from the unaffected kidney. We compared the sensitivity of P40 to T1/2 to identify symptomatic UPJO. RESULTS: In our cohort, 51% of symptomatic patients (n = 19) had a normal T1/2 (median 8.9 minutes; interquartile range: 7.5 minutes) and 49% (n = 18) had an abnormal T1/2 (median: 40 minutes; interquartile range: 0 minute). None of the patients had an abnormal P40 on their unaffected kidney. All patients with an abnormal T1/2 also had an abnormal P40. P40 increased the sensitivity of the renal scan from 49% (n = 18 of 37) to 73% (n = 27 of 37) when compared to T1/2. The majority of patients (95%) demonstrated an improvement in P40 after pyeloplasty. CONCLUSION: P40 markedly increases the sensitivity of a renal scan for diagnosing symptomatic UPJO and may be another valuable marker in addition to T1/2 to document functional improvement in drainage after pyeloplasty.
OBJECTIVE: To increase the diagnostic sensitivity of standard MAG3 diuretic renal scans for ureteropelvic junction obstruction (UPJO) by exploring the utility of an alternative measurement P40, the percentage of maximal tracer counts present at 40 minutes. MATERIALS AND METHODS:Patients with strong clinical and anatomic evidence for UPJO may have a normal T1/2, making definitive diagnosis difficult. We reviewed the charts of 142 consecutive patients who underwent successful laparoscopic or robotic-assisted laparoscopic pyeloplasty for UPJO between 2005 and 2015. Both pre- and postoperative renal scan images were available for 37 symptomatic patients with primary unilateral UPJO and 2 kidneys. We defined P40 as the percentage of maximal tracer counts present at 40 minutes. We identified the upper limit of normal (97.5th percentile, +2SD) for P40 using the preoperative renal scans from the unaffected kidney. We compared the sensitivity of P40 to T1/2 to identify symptomatic UPJO. RESULTS: In our cohort, 51% of symptomatic patients (n = 19) had a normal T1/2 (median 8.9 minutes; interquartile range: 7.5 minutes) and 49% (n = 18) had an abnormal T1/2 (median: 40 minutes; interquartile range: 0 minute). None of the patients had an abnormal P40 on their unaffected kidney. All patients with an abnormal T1/2 also had an abnormal P40. P40 increased the sensitivity of the renal scan from 49% (n = 18 of 37) to 73% (n = 27 of 37) when compared to T1/2. The majority of patients (95%) demonstrated an improvement in P40 after pyeloplasty. CONCLUSION: P40 markedly increases the sensitivity of a renal scan for diagnosing symptomatic UPJO and may be another valuable marker in addition to T1/2 to document functional improvement in drainage after pyeloplasty.
Authors: Asim Ozayar; Justin I Friedlander; Nabeel A Shakir; Jeffrey C Gahan; Jeffrey A Cadeddu; Monica S C Morgan Journal: J Urol Date: 2014-10-30 Impact factor: 7.450
Authors: Jason M Scovell; Friedrich-Carl von Rundstedt; Shelly X Bian; Dominic Lee; Wesley A Mayer; Richard E Link Journal: Urology Date: 2017-03-01 Impact factor: 2.649