- Email: [email protected]
THE EFFECT OF ULTRA LOW-DOSE RADIATION CT PROTOCOLS UPON DETECTION OF DISTAL URETERAL CALCULI
830
THE JOURNAL OF UROLOGY®
METHODS: We retrospectively reviewed all ureteroscopies performed at our institution by one staff surgeon between August 2003 and June 2008 and noted preoperative, intraoperative, and postoperative details of each case. Of 438 ureteroscopies, 289 underwent a strict follow-up protocol of RUS at ~ 1 month from the date of operation or from the date of stent removal. RESULTS: Renal ultrasound was performed at a mean of 54 days postoperatively. Of 289 patients with proper follow-up, 27 (9.3%) had sonographic demonstration of hydronephrosis. 14 were asymptomatic, and 13 experienced ipsilateral flank pain. There was no statistically significant difference between the asymptomatic and the symptomatic groups with respect to the need for further surgery (21% vs 38%, p=0.42). The number of RUS of asymptomatic patients required to detect one case of obstruction postoperatively (NNT) was 18. CONCLUSIONS: “Silent” hydronephrosis following ureteroscopy may warrant further surgery at the same rate as symptomatic patients. Renal ultrasonography at 1 month ensures appropriate detection of asymptomatic hydronephrosis, and should be considered an integral imaging modality during the post-operative period.
Vol. 181, No. 4, Supplement, Wednesday, April 29, 2009
postoperatively in man undergoing radical prostatectomy (RP) has been the fluorocystography. Transperineal ultrasound (TPUS) has the potential to assess for anastomotic leak and provide additional anatomic information . We aimed to compare the ability of TPUS and Flurocystography to detect anastomotic leak following RP. METHODS: METHODS: Between May 1, 2007 and October 1, 2008 175 consecutive men underwent RP by two surgeons (151 open, 24 robotic). Prior to Foley catheter removal both TPUS and Fluorocystography were performed and interpreted by a single radiologist. TPUS was performed first with imaging obtained real-time following gravity-fill of the bladder with 150cc of normal saline. Extravasation volume of saline was classified as slight if <20cc, moderate if 21-70cc, or severe if >70cc. Fluorocystography was performed after TPUS as per standard protocol with qualitative classification of leakage as non, slight leakage, moderate or severe. RESULTS: RESULTS: Of the 175 patients included in the study, 142 (81%) demonstrated no anastomotic leak on TPUS. Of the remaining 33 patients, TPUS identified 20 (11.4%) with slight leaks, 13 (7.4%) with moderate leaks. There were no patients with severe leaks. TPUS evaluation also included visualization and quantification of perianastomotic fluid collections and measurement of membranous urethral length. Fluorocystography confirmed the presence and degree of leaks in the 33 patients identified by TPUS and failed to demonstrate any leaks in patients with no leak on TPUS. CONCLUSIONS: The concordance of TPUS and fluorocystography for assessing anastomotic leak following RP was 100%. TPUS provides a safe, cost-effective alternative to the traditional fluorocystogram while also providing the advantage of direct visualization of peri-anastomotic anatomy. Figure 1. Normal Perineal Sonographic Anatomy (NPSA) and degree of anastomotic leak visualized by transperineal ultrasound. A: NPSA (1=pubic bone, 2=periurethral fat, 3=rectum, 4=vesicourethral anastomosis, 5=bulb of penis); B: slight leak (<20cc); C: moderate leak (20-70cc), D: Doppler imaging of peri-anastomotic inflammation
Source of Funding: None
Source of Funding: None
2290
2289
THE EFFECT OF ULTRA LOW-DOSE RADIATION CT PROTOCOLS UPON DETECTION OF DISTAL URETERAL CALCULI
TRANSPERINEAL ULTRASONOGRAPHY : POTENTIAL FOR A NEW STANDARD IN ASSESSING ANASTOMOTIC LEAK POSTRADICAL PROSTATECTOMY
Forrest C Jellison*, Lesli I Nicolay, John P. Heldt, Jason C. Smith, Nathan Spengler, Herbert C Ruckle, D Duane Baldwin, Loma Linda, CA
Shpetim Telegrafi*, Timothy Ito, Mariana Kozirovsky, Juliana Laze, Herbert Lepor, New York, NY INTRODUCTION AND OBJECTIVE: INTRODUCTION AND OBJECTIVE: The “gold standard” to assess anastomotic leak
INTRODUCTION AND OBJECTIVE: Unenhanced multi-detector computed tomography (MDCT) has become the diagnostic imaging modality of choice for urinary calculi. A single CT scan of the abdomen/ pelvis using conventional scanning parameters may expose the patient to 20 mSv of radiation and result in up to 1/1000 patients developing a
Vol. 181, No. 4, Supplement, Wednesday, April 29, 2009
fatal cancer. The purpose of this study is to compare the ability of ultra low-dose radiation protocols to conventional scanning protocols for detection of distal ureteral calculi. METHODS: This cadaver model was designed to simulate the most difficult clinical scenario possible, i.e. no hydronephrosis, arms unable to be lifted above the head (increased interference) and multiple phleboliths. Entire urinary tracts were previously prepared by inserting from 0 to 3 calcium oxalate stones ranging in size from 3-7 mm. Stones were placed into 14 cadaveric distal ureters in 56 random configurations. All urinary tracts were placed into the cadaver and scanned using MDCT at 140, 100, 60, 30, 15, and 7.5 mAs with other imaging parameters held constant. Images were reconstructed with a 2.5 mm section width, randomized, and reviewed independently by two blinded radiologists. RESULTS: Overall sensitivity and specificity of distal ureteral calculi detection were 96.4% and 87.0%, respectively. Despite ultra-low radiation exposure the sensitivity and specificity for detecting ureteral calculi was not reduced. There were no significant differences observed in the sensitivity or specificity between any radiation settings tested. Detection rates for 140, 100, 60, 30, 15, and 7.5 mAs settings had sensitivities of 98%, 97%, 97%, 95%, 95%, and 95% and specificities of 87%, 88%, 87%, 90%, 83%, and 87%, respectively. Inter-observer agreement was excellent with K=0.96. CONCLUSIONS: 1.) The sensitivity and specificity for the detection of distal ureteral calculi were statistically similar at all radiation settings tested. 2.)The ultra low-dose radiation protocol (7.5 mAs), equivalent to a KUB, reduced radiation exposure by 95% compared to conventional MDCT parameters (140 mAs). 3.) Low-dose protocols may significantly lower the risk of secondary malignancies due to radiation exposure. Source of Funding: None
THE JOURNAL OF UROLOGY®
831
THE JOURNAL OF UROLOGY®
METHODS: We retrospectively reviewed all ureteroscopies performed at our institution by one staff surgeon between August 2003 and June 2008 and noted preoperative, intraoperative, and postoperative details of each case. Of 438 ureteroscopies, 289 underwent a strict follow-up protocol of RUS at ~ 1 month from the date of operation or from the date of stent removal. RESULTS: Renal ultrasound was performed at a mean of 54 days postoperatively. Of 289 patients with proper follow-up, 27 (9.3%) had sonographic demonstration of hydronephrosis. 14 were asymptomatic, and 13 experienced ipsilateral flank pain. There was no statistically significant difference between the asymptomatic and the symptomatic groups with respect to the need for further surgery (21% vs 38%, p=0.42). The number of RUS of asymptomatic patients required to detect one case of obstruction postoperatively (NNT) was 18. CONCLUSIONS: “Silent” hydronephrosis following ureteroscopy may warrant further surgery at the same rate as symptomatic patients. Renal ultrasonography at 1 month ensures appropriate detection of asymptomatic hydronephrosis, and should be considered an integral imaging modality during the post-operative period.
Vol. 181, No. 4, Supplement, Wednesday, April 29, 2009
postoperatively in man undergoing radical prostatectomy (RP) has been the fluorocystography. Transperineal ultrasound (TPUS) has the potential to assess for anastomotic leak and provide additional anatomic information . We aimed to compare the ability of TPUS and Flurocystography to detect anastomotic leak following RP. METHODS: METHODS: Between May 1, 2007 and October 1, 2008 175 consecutive men underwent RP by two surgeons (151 open, 24 robotic). Prior to Foley catheter removal both TPUS and Fluorocystography were performed and interpreted by a single radiologist. TPUS was performed first with imaging obtained real-time following gravity-fill of the bladder with 150cc of normal saline. Extravasation volume of saline was classified as slight if <20cc, moderate if 21-70cc, or severe if >70cc. Fluorocystography was performed after TPUS as per standard protocol with qualitative classification of leakage as non, slight leakage, moderate or severe. RESULTS: RESULTS: Of the 175 patients included in the study, 142 (81%) demonstrated no anastomotic leak on TPUS. Of the remaining 33 patients, TPUS identified 20 (11.4%) with slight leaks, 13 (7.4%) with moderate leaks. There were no patients with severe leaks. TPUS evaluation also included visualization and quantification of perianastomotic fluid collections and measurement of membranous urethral length. Fluorocystography confirmed the presence and degree of leaks in the 33 patients identified by TPUS and failed to demonstrate any leaks in patients with no leak on TPUS. CONCLUSIONS: The concordance of TPUS and fluorocystography for assessing anastomotic leak following RP was 100%. TPUS provides a safe, cost-effective alternative to the traditional fluorocystogram while also providing the advantage of direct visualization of peri-anastomotic anatomy. Figure 1. Normal Perineal Sonographic Anatomy (NPSA) and degree of anastomotic leak visualized by transperineal ultrasound. A: NPSA (1=pubic bone, 2=periurethral fat, 3=rectum, 4=vesicourethral anastomosis, 5=bulb of penis); B: slight leak (<20cc); C: moderate leak (20-70cc), D: Doppler imaging of peri-anastomotic inflammation
Source of Funding: None
Source of Funding: None
2290
2289
THE EFFECT OF ULTRA LOW-DOSE RADIATION CT PROTOCOLS UPON DETECTION OF DISTAL URETERAL CALCULI
TRANSPERINEAL ULTRASONOGRAPHY : POTENTIAL FOR A NEW STANDARD IN ASSESSING ANASTOMOTIC LEAK POSTRADICAL PROSTATECTOMY
Forrest C Jellison*, Lesli I Nicolay, John P. Heldt, Jason C. Smith, Nathan Spengler, Herbert C Ruckle, D Duane Baldwin, Loma Linda, CA
Shpetim Telegrafi*, Timothy Ito, Mariana Kozirovsky, Juliana Laze, Herbert Lepor, New York, NY INTRODUCTION AND OBJECTIVE: INTRODUCTION AND OBJECTIVE: The “gold standard” to assess anastomotic leak
INTRODUCTION AND OBJECTIVE: Unenhanced multi-detector computed tomography (MDCT) has become the diagnostic imaging modality of choice for urinary calculi. A single CT scan of the abdomen/ pelvis using conventional scanning parameters may expose the patient to 20 mSv of radiation and result in up to 1/1000 patients developing a
Vol. 181, No. 4, Supplement, Wednesday, April 29, 2009
fatal cancer. The purpose of this study is to compare the ability of ultra low-dose radiation protocols to conventional scanning protocols for detection of distal ureteral calculi. METHODS: This cadaver model was designed to simulate the most difficult clinical scenario possible, i.e. no hydronephrosis, arms unable to be lifted above the head (increased interference) and multiple phleboliths. Entire urinary tracts were previously prepared by inserting from 0 to 3 calcium oxalate stones ranging in size from 3-7 mm. Stones were placed into 14 cadaveric distal ureters in 56 random configurations. All urinary tracts were placed into the cadaver and scanned using MDCT at 140, 100, 60, 30, 15, and 7.5 mAs with other imaging parameters held constant. Images were reconstructed with a 2.5 mm section width, randomized, and reviewed independently by two blinded radiologists. RESULTS: Overall sensitivity and specificity of distal ureteral calculi detection were 96.4% and 87.0%, respectively. Despite ultra-low radiation exposure the sensitivity and specificity for detecting ureteral calculi was not reduced. There were no significant differences observed in the sensitivity or specificity between any radiation settings tested. Detection rates for 140, 100, 60, 30, 15, and 7.5 mAs settings had sensitivities of 98%, 97%, 97%, 95%, 95%, and 95% and specificities of 87%, 88%, 87%, 90%, 83%, and 87%, respectively. Inter-observer agreement was excellent with K=0.96. CONCLUSIONS: 1.) The sensitivity and specificity for the detection of distal ureteral calculi were statistically similar at all radiation settings tested. 2.)The ultra low-dose radiation protocol (7.5 mAs), equivalent to a KUB, reduced radiation exposure by 95% compared to conventional MDCT parameters (140 mAs). 3.) Low-dose protocols may significantly lower the risk of secondary malignancies due to radiation exposure. Source of Funding: None
THE JOURNAL OF UROLOGY®
831