Franklin Lee - Academia.edu (original) (raw)
Papers by Franklin Lee
Urology, 2016
To investigate whether the use of a belladonna and opium (B&O) rectal sup... more To investigate whether the use of a belladonna and opium (B&O) rectal suppository administered immediately before ureteroscopy (URS) and stent placement could reduce stent-related discomfort. A randomized, double-blinded, placebo-controlled study was performed from August 2013 to December 2014. Seventy-one subjects were enrolled and randomized to receive a B&O (15 mg/30 mg) or a placebo suppository after induction of general anesthesia immediately before URS and stent placement. Baseline urinary symptoms were assessed using the American Urological Association Symptom Score (AUASS). The Ureteral Stent Symptom Questionnaire and AUASS were completed on postoperative days (POD) 1, 3, and after stent removal. Analgesic use intraoperatively, in the recovery unit, and at home was recorded. Of the 71 subjects, 65 had treatment for ureteral (41%) and renal (61%) calculi, 4 for renal urothelial carcinoma, and 2 were excluded for no stent placed. By POD3, the B&O group reported a higher mean global quality of life (QOL) score (P = .04), a better mean quality of work score (P = .05), and less pain with urination (P = .03). The B&O group reported an improved AUASS QOL when comparing POD1 with post-stent removal (P = .04). There was no difference in analgesic use among groups (P = .67). There were no episodes of urinary retention. Age was associated with unplanned emergency visits (P <.00) and "high-pain" measure (P = .02) CONCLUSION: B&O suppository administered preoperatively improved QOL measures and reduced urinary-related pain after URS with stent. Younger age was associated with severe stent pain and unplanned hospital visits.
The Journal of Urology, 2015
INTRODUCTION AND OBJECTIVES: Unlike adult stone formers, ultrasound is often exclusively used in ... more INTRODUCTION AND OBJECTIVES: Unlike adult stone formers, ultrasound is often exclusively used in both the initial diagnosis and the follow-up of pediatric stone formers. As such, treatment decisions are made based on ultrasound findings alone. Ultrasound has been shown to consistently overestimate stone size, which could lead to surgical intervention for a stone that may spontaneously pass. Our group has previously demonstrated that the posterior acoustic shadow is a more accurate predictor of true stone size in an in vitro model. We sought to determine the prevalence and accuracy of the posterior acoustic shadow in a pediatric cohort. METHODS: A retrospective analysis was performed of all pediatric stone patient encounters at a children’s hospital over the last 10 years using the ICD-9 code for nephrolithiasis (592.0). All included subjects had a stone present on computed tomography (CT) scan and renal ultrasound, taken within 3 months of each other for an initial stone event. The size of the stone and posterior acoustic shadow were measured on ultrasound by two board certified radiologists and compared to stone size as measured on CT. RESULTS: Of 633 charts reviewed, 37 patients with 49 kidney stones were included in this study. Mean age was 13 4 years with a mean BMI of 19 6 kg/m2 and mean stone size of 7.2 2.9 based on CT. A posterior acoustic shadow was seen in 85% of stones evaluated and found to be a significantly (p < 0.001) better predictor of true stone size. When compared to CT, measuring the stone directly resulted in an average overestimation of 2.0 1.5 mm, while measuring the acoustic shadow resulted in an underestimation of 0.4 2.5 mm. CONCLUSIONS: In this retrospective study, the posterior acoustic shadow was seen in the majority of stones. Measuring the shadow was a more accurate measure of true stone size and may provide valuable prognostic information to help guide clinicians in counseling families about surveillance or surgical management of renal stones. This is particularly relevant to the pediatric population and may reduce unnecessary procedures and further decrease reliance on CT imaging. The results may be improved in a prospective study where the image is optimized for a shadow measurement.
The Journal of Urology, 2015
The Journal of the Acoustical Society of America, 2014
ABSTRACT Previous studies have shown overestimation of kidney stone size in ultrasound images. We... more ABSTRACT Previous studies have shown overestimation of kidney stone size in ultrasound images. We explored measuring the stone's acoustic shadow as a predictor of stone size. Forty-five calcium oxalate monohydrate (COM) kidney stones ranging from 1 to 10 mm were imaged in a water bath using a research-based ultrasound system and C5-2 transducer. Stones were imaged at depths of 6, 10, and 14 cm. The widths across the stone image and across acoustic shadow distal to the stone image were measured by the operator and through an automated algorithm. Measuring size across the stone image consistently overestimated: overestimation was 0.9±0.8 mm, 1.5±1.0 mm, 2.0±1.2 mm (manual) and 0.5±1.7 mm, 0.4±1.5 mm, 0.8±1.1 mm (automated) at 6, 10, and 14 cm depths. Measurement of the acoustic shadow width more accurately estimated stone size: 0.0±0.4 mm, 0.0±0.6 mm, and-0.2±0.8 mm (manual) and 0.2±0.5 mm, 0.1±0.8 mm, and 0.1±1.0 mm (automated) at 6, 10, and 14 cm depths. Measurement from the shadow reduced misclassification of passable stones <5 mm to requiring surgery >5 mm from 25% to 7%. The results have implications for directing treatment of asymptomatic stones based on ultrasound images. [Work supported by NIH DK043881, DK092197, and NSBRI through NASA NCC 9-58.].
The Journal of the Acoustical Society of America, 2014
Burst wave lithotripsy is a novel technology that uses focused, sinusoidal bursts of ultrasound t... more Burst wave lithotripsy is a novel technology that uses focused, sinusoidal bursts of ultrasound to fragment kidney stones. Prior research laid the groundwork to design an extracorporeal, image-guided probe for in-vivo testing and potentially human clinical testing. Toward this end, a 12-element 330 kHz array transducer was designed and built. The probe frequency, geometry, and shape were designed to break stones up to 1 cm in diameter into fragments <2mm. A custom amplifier capable of generating output bursts up to 3 kV was built to drive the array. To facilitate image guidance, the transducer array was designed with a central hole to accommodate co-axial attachment of an HDI P4-2 probe. Custom B-mode and Doppler imaging sequences were developed and synchronized on a Verasonics ultrasound engine to enable real-time stone targeting and cavitation detection, Preliminary data suggest that natural stones will exhibit Doppler “twinkling” artifact in the BWL focus and that the Doppler power increases as the sto...
Journal of endourology / Endourological Society, 2015
Ultrasound (US) overestimates stone size when compared with CT. The purpose of this work was to e... more Ultrasound (US) overestimates stone size when compared with CT. The purpose of this work was to evaluate the overestimation of stone size with US in an in vitro water bath model and investigate methods to reduce overestimation. Ten human stones (3-12 mm) were measured using B-mode (brightness mode) US by a sonographer blinded to the true stone size. Images were captured and compared using both a commercial US machine and software-based research US device. Image gain was adjusted between moderate and high stone intensities, and the transducer-to-stone depth was varied from 6 to 10 cm. A computerized stone-sizing program was developed to outline the stone width based on a grayscale intensity threshold. Overestimation with the commercial device increased with both gain and depth. Average overestimation at moderate and high gain was 1.9±0.8 and 2.1±0.9 mm, respectively (p=0.6). Overestimation increased an average of 22% with an every 2-cm increase in depth (p=0.02). Overestimation using...
Urology, 2013
The image we present demonstrates the classic hexagonal crystals that are diagnostic of cysteine ... more The image we present demonstrates the classic hexagonal crystals that are diagnostic of cysteine crystals in a 14-year-old girl with cystinuria. These crystals developed on her stent within a 2-week period after treatment of her stone. The image illustrates the importance of urine microscopy and basic urologic knowledge.
The Journal of Urology, 2011
The Journal of Urology, 2014
INTRODUCTION AND OBJECTIVES: While ultrasound is readily available, relatively less expensive tha... more INTRODUCTION AND OBJECTIVES: While ultrasound is readily available, relatively less expensive than CT, and does not produce ionizing radiation; it is known to overestimate and inaccurately measure stone size. We explored the use of measuring the acoustic shadow behind kidney stones as a better predictor of true stone size. METHODS: 45 calcium oxalate monohydrate kidney stones ranging from 1-10 mm were imaged in a water bath using a research-based ultrasound system with a C5-2 transducer. Stones were imaged at depths of 6, 10, and 14 cm. Under B-mode ultrasound, the width of both the stone and stone acoustic shadow was measured at each depth for every stone. Three blinded reviewers (2 urologists and an ultrasonagropher) independently performed each measurement. A linear mixed-effect model was used to account for within-stone correlations, and compare stone and shadow measurements for each size, depth, and user. Subgroup analysis was performed to determine the percentage of stones that were over-classified as greater than 5 mm when true stone size was less than 5 mm. RESULTS: Stone size was consistently overestimated when directly measuring stone width. Average overestimation was 1.1±0.8 mm, 1.9±1.0 mm, 2.7±1.4 mm at 6, 10, 14 cm depths, respectively. Overestimation increased with increasing depth (p<0.01). The acoustic shadow technique resulted in an overestimation of 0.2±0.8 mm, 0.0±1.1 mm, and 0.2±1.2 mm at 6, 10, 14 cm depths, respectively. The acoustic shadow technique was a better predictor of true stone size at all depths and sizes compared to measuring the stone width (p<0.001 at each depth). Subgroup analysis demonstrated that over-classification occurred in 15/60 (25%) when the stone was measured and 4/60 (7%) when measuring the posterior acoustic shadow. CONCLUSIONS: There is consistent overestimation using the stone width under B-mode ultrasound, with increasing overestimation with increasing depth. Use of the acoustic shadow width significantly reduces overestimation and decreases overclassification by 18% for stones less than 5 mm.
The Journal of Urology, 2014
The Journal of Urology, 2013
The Journal of the Acoustical Society of America, 2013
Our group has introduced transcutaneous ultrasound to move kidney stones in order to expel small ... more Our group has introduced transcutaneous ultrasound to move kidney stones in order to expel small stones or relocate an obstructing stone to a nonobstructing location. Human stones and metalized beads (2-8 mm) were implanted ureteroscopically in kidneys of eight domestic swine. Ultrasonic propulsion was performed using a diagnostic imaging transducer and a Verasonics ultrasound platform. Stone propulsion was visualized using fluoroscopy, ultrasound, and the ureteroscope. Successful stone movement was defined as relocating a stone to the renal pelvis, ureteropelvic junction (UPJ) or proximal ureter. Three blinded experts evaluated for histologic injury in control and treatment arms. All stones were moved. 65% (17/26) of stones/beads were moved the entire distance to the renal pelvis (3), UPJ (2), or ureter (12). Average successful procedure per stone required 14±8 min and 23±16 pushes. Each push averaged 0.9 s in duration. Mean interval between pushes was 41±13 sec. No gross or histologic kidney damage was identified in six kidneys from exposure to 20 1-s pushes spaced by 33 s. Ultrasonic propulsion is effective with most stones being relocated to the renal pelvis, UPJ, or ureter. The procedure appears safe without evidence of injury. Supported by NIH DK43881, DK092197 and NSBRI through NASA NCC 9-58.
European Urology, 2001
To compare the outcome of outpatient ureteroscopic laser lithotripsy (URSL) for ureteral stone la... more To compare the outcome of outpatient ureteroscopic laser lithotripsy (URSL) for ureteral stone larger than 10 mm in longest diameter (group 1) with those less than or equal to 10 mm (group 2). 134 patients with solitary ureteral stone were treated by outpatient URSL. No exclusion criteria with regards to stone size, level or composition were applied. Semirigid ureteroscopy and holmium-YAG laser lithotripsy was performed under general anaesthesia as outpatient procedure. Radiological follow-up by intravenous urogram was performed 3 months postoperatively. Patients' demographic data, stone parameters, operative details and treatment outcome were collected prospectively and compared between the two groups. Among the 134 ureteral stones, 41(31%) were larger than 10 mm. Group 1 contained more upper and middle ureteral stones than group 2 (68 vs. 40% p = 0.001). Operating time was significantly longer for group 1 (68.9 vs. 46.8 min, p<0.001) and postoperative stenting rate was higher (83 vs. 60%, p = 0.01). There was no difference between the groups in terms of 3 months stone clearance rate (92.7 vs. 91.4%, p = 0.8). Complication rate was higher in group 1 (22 vs. 5.4%, p = 0.004) especially for lower stones (46.2 vs. 5.4%, p = 0.001) but most of which were minor complications that were treated conservatively. One patient in group 1 (2.4%) developed ureteral stricture at the longstanding stone impaction site despite postoperative stenting. The stricture resolved subsequent to balloon dilatation. URSL can treat stones larger than 10 mm in longest diameter at all levels safely and effectively in an outpatient setting.
Biopolymers, 2006
Amino acids with N-alkylaminooxy side chains have proven effective for the rapid synthesis of neo... more Amino acids with N-alkylaminooxy side chains have proven effective for the rapid synthesis of neoglycopeptides. Chemoselective reaction of reducing sugars with peptides containing these amino acids provides glycoconjugates that are structurally similar to their natural counterparts. 2-(N-Fmoc)-3-(N-Boc-N-methoxy)-diaminopropanoic acid (Fmoc: 9-fluorenylmethoxycarbonyl; Boc: t-butyloxycarbonyl) was synthesized from Boc-Ser-OH in >40% overall yield and incorporated into peptides by standard Fmoc chemistry based solid phase peptide synthesis. The resulting peptides are efficiently glycosylated and serve as mimics of O-linked glycopeptides. The synthesis of this derivative greatly expands the availability of the N-alkylaminooxy strategy for neoglycopeptides.
Journal of endourology, 2000
To evaluate a policy of selective, short-duration internal stenting after outpatient ureteroscopi... more To evaluate a policy of selective, short-duration internal stenting after outpatient ureteroscopic laser lithotripsy. From January 1997 to April 1998, 62 patients (34 male, 28 female) with a mean age of 50 (range 21-80) years underwent outpatient ureteroscopic lithotripsy using a holmium laser (365 microm; 0.5-1.4J/5-10 Hz) and 6F/7.5F semirigid ureteroscope. Internal stents were inserted selectively in patients with severe preoperative obstruction (intravenous urogram finding), tight stone impaction (endoscopic finding), or significant residual obstruction (on-table retrograde pyelogram finding) despite stone clearance. Patient demographics, stone measures, stone clearance rates, complications, postoperative pain scores, analgesic requirement, and follow-up imaging were compared for the stented and unstented patients. With the present criteria of selective internal stenting, stents were inserted in 56% of the patients for a mean duration of 3.6 weeks. Excluding those patients with residual stones requiring further interventions, the stenting rate was 39% with a mean duration of 1.9 weeks. There was no difference in patient characteristics, stone burden, and stone levels between the stented and unstented group. The mean operating time for the unstented group was shorter than for the stented group (45.6 minutes v 56.6 minutes; P = 0.03). The stone clearance rates were similar for the two groups (96% v 97%), but the complication rate of the stented group was higher (8.6% v 3.7%). The mean postoperative pain score and analgesic requirement were similar in the two groups on postoperative day 1 but significantly less in the unstented group on day 3. The criteria for selective internal stenting are useful in determining when a stent should be used. By omitting the stent insertion in the absence of these criteria, operating time, postoperative pain, and analgesic requirement were reduced without increasing the complication rate. Ureteral stricturing was absent despite the low stenting rate.
Journal of Therapeutic Ultrasound, 2015
Background/introduction Ultrasonic propulsion is a new technology we have developed which uses fo... more Background/introduction Ultrasonic propulsion is a new technology we have developed which uses focused ultrasound to transcutaneously reposition kidney stones. Two applications are expelling small stones or fragments and dislodging obstructing stones. We report preliminary, investigative findings from the first use of this technology in humans.
Advances in urology, 2013
Objectives. To compare pathologic outcomes after treatment with gemcitabine and cisplatin (GC) ve... more Objectives. To compare pathologic outcomes after treatment with gemcitabine and cisplatin (GC) versus methotrexate, vinblastine, adriamycin, and cisplatin (MVAC) in the neoadjuvant setting. Methods. Data was retrospectively collected on 178 patients with T2-T4 bladder cancer who underwent radical cystectomy between 2003 and 2011. Outcomes of interest included those with complete response (pT0) and any response (≤pT1). Odds ratios were calculated using multivariate logistic regression. Results. Compared to those who did not receive neoadjuvant chemotherapy, there were more patients with complete response (28% versus 9%, OR 3.11 (95% CI: 1.45-6.64), P = 0.03) and any response (52% versus 25%, OR 3.23 (95% CI: 1.21-8.64), P = 0.01). Seventy-two patients received GC (n = 41) or MVAC (n = 31). CR was achieved in 29% and 22% of GC and MVAC patients, respectively (multivariate OR 0.39, 95% CI 0.10-1.58). Any response (≤pT1) was achieved in 56% of GC and 45% of MVAC patients (multivariate O...
European Urology Supplements, 2003
2014 IEEE International Ultrasonics Symposium, 2014
Kidney stones have been shown to exhibit a &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;a... more Kidney stones have been shown to exhibit a &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;twinkling artifact&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; (TA) under Color-Doppler ultrasound. Although this technique has better specificity than conventional Bmode imaging, it has lower sensitivity. To improve the overall performance of using TA as a diagnostic tool, Doppler output parameters were optimized in-vitro. The collected data supports a previous hypothesis that TA is caused by random oscillations of micron sized bubbles trapped in the cracks and crevices of kidney stones. A set of optimized parameters were implemented such that that the MI &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp; TI remained within the FDA approved limits. Several clinical kidney scans were performed with the optimized settings and were able to detect stones with improved SNR relative to the default settings.
Urology, 2016
To investigate whether the use of a belladonna and opium (B&amp;amp;amp;amp;O) rectal sup... more To investigate whether the use of a belladonna and opium (B&amp;amp;amp;amp;O) rectal suppository administered immediately before ureteroscopy (URS) and stent placement could reduce stent-related discomfort. A randomized, double-blinded, placebo-controlled study was performed from August 2013 to December 2014. Seventy-one subjects were enrolled and randomized to receive a B&amp;amp;amp;amp;O (15 mg/30 mg) or a placebo suppository after induction of general anesthesia immediately before URS and stent placement. Baseline urinary symptoms were assessed using the American Urological Association Symptom Score (AUASS). The Ureteral Stent Symptom Questionnaire and AUASS were completed on postoperative days (POD) 1, 3, and after stent removal. Analgesic use intraoperatively, in the recovery unit, and at home was recorded. Of the 71 subjects, 65 had treatment for ureteral (41%) and renal (61%) calculi, 4 for renal urothelial carcinoma, and 2 were excluded for no stent placed. By POD3, the B&amp;amp;amp;amp;O group reported a higher mean global quality of life (QOL) score (P = .04), a better mean quality of work score (P = .05), and less pain with urination (P = .03). The B&amp;amp;amp;amp;O group reported an improved AUASS QOL when comparing POD1 with post-stent removal (P = .04). There was no difference in analgesic use among groups (P = .67). There were no episodes of urinary retention. Age was associated with unplanned emergency visits (P &amp;amp;amp;lt;.00) and &amp;amp;amp;quot;high-pain&amp;amp;amp;quot; measure (P = .02) CONCLUSION: B&amp;amp;amp;amp;O suppository administered preoperatively improved QOL measures and reduced urinary-related pain after URS with stent. Younger age was associated with severe stent pain and unplanned hospital visits.
The Journal of Urology, 2015
INTRODUCTION AND OBJECTIVES: Unlike adult stone formers, ultrasound is often exclusively used in ... more INTRODUCTION AND OBJECTIVES: Unlike adult stone formers, ultrasound is often exclusively used in both the initial diagnosis and the follow-up of pediatric stone formers. As such, treatment decisions are made based on ultrasound findings alone. Ultrasound has been shown to consistently overestimate stone size, which could lead to surgical intervention for a stone that may spontaneously pass. Our group has previously demonstrated that the posterior acoustic shadow is a more accurate predictor of true stone size in an in vitro model. We sought to determine the prevalence and accuracy of the posterior acoustic shadow in a pediatric cohort. METHODS: A retrospective analysis was performed of all pediatric stone patient encounters at a children’s hospital over the last 10 years using the ICD-9 code for nephrolithiasis (592.0). All included subjects had a stone present on computed tomography (CT) scan and renal ultrasound, taken within 3 months of each other for an initial stone event. The size of the stone and posterior acoustic shadow were measured on ultrasound by two board certified radiologists and compared to stone size as measured on CT. RESULTS: Of 633 charts reviewed, 37 patients with 49 kidney stones were included in this study. Mean age was 13 4 years with a mean BMI of 19 6 kg/m2 and mean stone size of 7.2 2.9 based on CT. A posterior acoustic shadow was seen in 85% of stones evaluated and found to be a significantly (p < 0.001) better predictor of true stone size. When compared to CT, measuring the stone directly resulted in an average overestimation of 2.0 1.5 mm, while measuring the acoustic shadow resulted in an underestimation of 0.4 2.5 mm. CONCLUSIONS: In this retrospective study, the posterior acoustic shadow was seen in the majority of stones. Measuring the shadow was a more accurate measure of true stone size and may provide valuable prognostic information to help guide clinicians in counseling families about surveillance or surgical management of renal stones. This is particularly relevant to the pediatric population and may reduce unnecessary procedures and further decrease reliance on CT imaging. The results may be improved in a prospective study where the image is optimized for a shadow measurement.
The Journal of Urology, 2015
The Journal of the Acoustical Society of America, 2014
ABSTRACT Previous studies have shown overestimation of kidney stone size in ultrasound images. We... more ABSTRACT Previous studies have shown overestimation of kidney stone size in ultrasound images. We explored measuring the stone's acoustic shadow as a predictor of stone size. Forty-five calcium oxalate monohydrate (COM) kidney stones ranging from 1 to 10 mm were imaged in a water bath using a research-based ultrasound system and C5-2 transducer. Stones were imaged at depths of 6, 10, and 14 cm. The widths across the stone image and across acoustic shadow distal to the stone image were measured by the operator and through an automated algorithm. Measuring size across the stone image consistently overestimated: overestimation was 0.9±0.8 mm, 1.5±1.0 mm, 2.0±1.2 mm (manual) and 0.5±1.7 mm, 0.4±1.5 mm, 0.8±1.1 mm (automated) at 6, 10, and 14 cm depths. Measurement of the acoustic shadow width more accurately estimated stone size: 0.0±0.4 mm, 0.0±0.6 mm, and-0.2±0.8 mm (manual) and 0.2±0.5 mm, 0.1±0.8 mm, and 0.1±1.0 mm (automated) at 6, 10, and 14 cm depths. Measurement from the shadow reduced misclassification of passable stones <5 mm to requiring surgery >5 mm from 25% to 7%. The results have implications for directing treatment of asymptomatic stones based on ultrasound images. [Work supported by NIH DK043881, DK092197, and NSBRI through NASA NCC 9-58.].
The Journal of the Acoustical Society of America, 2014
Burst wave lithotripsy is a novel technology that uses focused, sinusoidal bursts of ultrasound t... more Burst wave lithotripsy is a novel technology that uses focused, sinusoidal bursts of ultrasound to fragment kidney stones. Prior research laid the groundwork to design an extracorporeal, image-guided probe for in-vivo testing and potentially human clinical testing. Toward this end, a 12-element 330 kHz array transducer was designed and built. The probe frequency, geometry, and shape were designed to break stones up to 1 cm in diameter into fragments <2mm. A custom amplifier capable of generating output bursts up to 3 kV was built to drive the array. To facilitate image guidance, the transducer array was designed with a central hole to accommodate co-axial attachment of an HDI P4-2 probe. Custom B-mode and Doppler imaging sequences were developed and synchronized on a Verasonics ultrasound engine to enable real-time stone targeting and cavitation detection, Preliminary data suggest that natural stones will exhibit Doppler “twinkling” artifact in the BWL focus and that the Doppler power increases as the sto...
Journal of endourology / Endourological Society, 2015
Ultrasound (US) overestimates stone size when compared with CT. The purpose of this work was to e... more Ultrasound (US) overestimates stone size when compared with CT. The purpose of this work was to evaluate the overestimation of stone size with US in an in vitro water bath model and investigate methods to reduce overestimation. Ten human stones (3-12 mm) were measured using B-mode (brightness mode) US by a sonographer blinded to the true stone size. Images were captured and compared using both a commercial US machine and software-based research US device. Image gain was adjusted between moderate and high stone intensities, and the transducer-to-stone depth was varied from 6 to 10 cm. A computerized stone-sizing program was developed to outline the stone width based on a grayscale intensity threshold. Overestimation with the commercial device increased with both gain and depth. Average overestimation at moderate and high gain was 1.9±0.8 and 2.1±0.9 mm, respectively (p=0.6). Overestimation increased an average of 22% with an every 2-cm increase in depth (p=0.02). Overestimation using...
Urology, 2013
The image we present demonstrates the classic hexagonal crystals that are diagnostic of cysteine ... more The image we present demonstrates the classic hexagonal crystals that are diagnostic of cysteine crystals in a 14-year-old girl with cystinuria. These crystals developed on her stent within a 2-week period after treatment of her stone. The image illustrates the importance of urine microscopy and basic urologic knowledge.
The Journal of Urology, 2011
The Journal of Urology, 2014
INTRODUCTION AND OBJECTIVES: While ultrasound is readily available, relatively less expensive tha... more INTRODUCTION AND OBJECTIVES: While ultrasound is readily available, relatively less expensive than CT, and does not produce ionizing radiation; it is known to overestimate and inaccurately measure stone size. We explored the use of measuring the acoustic shadow behind kidney stones as a better predictor of true stone size. METHODS: 45 calcium oxalate monohydrate kidney stones ranging from 1-10 mm were imaged in a water bath using a research-based ultrasound system with a C5-2 transducer. Stones were imaged at depths of 6, 10, and 14 cm. Under B-mode ultrasound, the width of both the stone and stone acoustic shadow was measured at each depth for every stone. Three blinded reviewers (2 urologists and an ultrasonagropher) independently performed each measurement. A linear mixed-effect model was used to account for within-stone correlations, and compare stone and shadow measurements for each size, depth, and user. Subgroup analysis was performed to determine the percentage of stones that were over-classified as greater than 5 mm when true stone size was less than 5 mm. RESULTS: Stone size was consistently overestimated when directly measuring stone width. Average overestimation was 1.1±0.8 mm, 1.9±1.0 mm, 2.7±1.4 mm at 6, 10, 14 cm depths, respectively. Overestimation increased with increasing depth (p<0.01). The acoustic shadow technique resulted in an overestimation of 0.2±0.8 mm, 0.0±1.1 mm, and 0.2±1.2 mm at 6, 10, 14 cm depths, respectively. The acoustic shadow technique was a better predictor of true stone size at all depths and sizes compared to measuring the stone width (p<0.001 at each depth). Subgroup analysis demonstrated that over-classification occurred in 15/60 (25%) when the stone was measured and 4/60 (7%) when measuring the posterior acoustic shadow. CONCLUSIONS: There is consistent overestimation using the stone width under B-mode ultrasound, with increasing overestimation with increasing depth. Use of the acoustic shadow width significantly reduces overestimation and decreases overclassification by 18% for stones less than 5 mm.
The Journal of Urology, 2014
The Journal of Urology, 2013
The Journal of the Acoustical Society of America, 2013
Our group has introduced transcutaneous ultrasound to move kidney stones in order to expel small ... more Our group has introduced transcutaneous ultrasound to move kidney stones in order to expel small stones or relocate an obstructing stone to a nonobstructing location. Human stones and metalized beads (2-8 mm) were implanted ureteroscopically in kidneys of eight domestic swine. Ultrasonic propulsion was performed using a diagnostic imaging transducer and a Verasonics ultrasound platform. Stone propulsion was visualized using fluoroscopy, ultrasound, and the ureteroscope. Successful stone movement was defined as relocating a stone to the renal pelvis, ureteropelvic junction (UPJ) or proximal ureter. Three blinded experts evaluated for histologic injury in control and treatment arms. All stones were moved. 65% (17/26) of stones/beads were moved the entire distance to the renal pelvis (3), UPJ (2), or ureter (12). Average successful procedure per stone required 14±8 min and 23±16 pushes. Each push averaged 0.9 s in duration. Mean interval between pushes was 41±13 sec. No gross or histologic kidney damage was identified in six kidneys from exposure to 20 1-s pushes spaced by 33 s. Ultrasonic propulsion is effective with most stones being relocated to the renal pelvis, UPJ, or ureter. The procedure appears safe without evidence of injury. Supported by NIH DK43881, DK092197 and NSBRI through NASA NCC 9-58.
European Urology, 2001
To compare the outcome of outpatient ureteroscopic laser lithotripsy (URSL) for ureteral stone la... more To compare the outcome of outpatient ureteroscopic laser lithotripsy (URSL) for ureteral stone larger than 10 mm in longest diameter (group 1) with those less than or equal to 10 mm (group 2). 134 patients with solitary ureteral stone were treated by outpatient URSL. No exclusion criteria with regards to stone size, level or composition were applied. Semirigid ureteroscopy and holmium-YAG laser lithotripsy was performed under general anaesthesia as outpatient procedure. Radiological follow-up by intravenous urogram was performed 3 months postoperatively. Patients' demographic data, stone parameters, operative details and treatment outcome were collected prospectively and compared between the two groups. Among the 134 ureteral stones, 41(31%) were larger than 10 mm. Group 1 contained more upper and middle ureteral stones than group 2 (68 vs. 40% p = 0.001). Operating time was significantly longer for group 1 (68.9 vs. 46.8 min, p<0.001) and postoperative stenting rate was higher (83 vs. 60%, p = 0.01). There was no difference between the groups in terms of 3 months stone clearance rate (92.7 vs. 91.4%, p = 0.8). Complication rate was higher in group 1 (22 vs. 5.4%, p = 0.004) especially for lower stones (46.2 vs. 5.4%, p = 0.001) but most of which were minor complications that were treated conservatively. One patient in group 1 (2.4%) developed ureteral stricture at the longstanding stone impaction site despite postoperative stenting. The stricture resolved subsequent to balloon dilatation. URSL can treat stones larger than 10 mm in longest diameter at all levels safely and effectively in an outpatient setting.
Biopolymers, 2006
Amino acids with N-alkylaminooxy side chains have proven effective for the rapid synthesis of neo... more Amino acids with N-alkylaminooxy side chains have proven effective for the rapid synthesis of neoglycopeptides. Chemoselective reaction of reducing sugars with peptides containing these amino acids provides glycoconjugates that are structurally similar to their natural counterparts. 2-(N-Fmoc)-3-(N-Boc-N-methoxy)-diaminopropanoic acid (Fmoc: 9-fluorenylmethoxycarbonyl; Boc: t-butyloxycarbonyl) was synthesized from Boc-Ser-OH in >40% overall yield and incorporated into peptides by standard Fmoc chemistry based solid phase peptide synthesis. The resulting peptides are efficiently glycosylated and serve as mimics of O-linked glycopeptides. The synthesis of this derivative greatly expands the availability of the N-alkylaminooxy strategy for neoglycopeptides.
Journal of endourology, 2000
To evaluate a policy of selective, short-duration internal stenting after outpatient ureteroscopi... more To evaluate a policy of selective, short-duration internal stenting after outpatient ureteroscopic laser lithotripsy. From January 1997 to April 1998, 62 patients (34 male, 28 female) with a mean age of 50 (range 21-80) years underwent outpatient ureteroscopic lithotripsy using a holmium laser (365 microm; 0.5-1.4J/5-10 Hz) and 6F/7.5F semirigid ureteroscope. Internal stents were inserted selectively in patients with severe preoperative obstruction (intravenous urogram finding), tight stone impaction (endoscopic finding), or significant residual obstruction (on-table retrograde pyelogram finding) despite stone clearance. Patient demographics, stone measures, stone clearance rates, complications, postoperative pain scores, analgesic requirement, and follow-up imaging were compared for the stented and unstented patients. With the present criteria of selective internal stenting, stents were inserted in 56% of the patients for a mean duration of 3.6 weeks. Excluding those patients with residual stones requiring further interventions, the stenting rate was 39% with a mean duration of 1.9 weeks. There was no difference in patient characteristics, stone burden, and stone levels between the stented and unstented group. The mean operating time for the unstented group was shorter than for the stented group (45.6 minutes v 56.6 minutes; P = 0.03). The stone clearance rates were similar for the two groups (96% v 97%), but the complication rate of the stented group was higher (8.6% v 3.7%). The mean postoperative pain score and analgesic requirement were similar in the two groups on postoperative day 1 but significantly less in the unstented group on day 3. The criteria for selective internal stenting are useful in determining when a stent should be used. By omitting the stent insertion in the absence of these criteria, operating time, postoperative pain, and analgesic requirement were reduced without increasing the complication rate. Ureteral stricturing was absent despite the low stenting rate.
Journal of Therapeutic Ultrasound, 2015
Background/introduction Ultrasonic propulsion is a new technology we have developed which uses fo... more Background/introduction Ultrasonic propulsion is a new technology we have developed which uses focused ultrasound to transcutaneously reposition kidney stones. Two applications are expelling small stones or fragments and dislodging obstructing stones. We report preliminary, investigative findings from the first use of this technology in humans.
Advances in urology, 2013
Objectives. To compare pathologic outcomes after treatment with gemcitabine and cisplatin (GC) ve... more Objectives. To compare pathologic outcomes after treatment with gemcitabine and cisplatin (GC) versus methotrexate, vinblastine, adriamycin, and cisplatin (MVAC) in the neoadjuvant setting. Methods. Data was retrospectively collected on 178 patients with T2-T4 bladder cancer who underwent radical cystectomy between 2003 and 2011. Outcomes of interest included those with complete response (pT0) and any response (≤pT1). Odds ratios were calculated using multivariate logistic regression. Results. Compared to those who did not receive neoadjuvant chemotherapy, there were more patients with complete response (28% versus 9%, OR 3.11 (95% CI: 1.45-6.64), P = 0.03) and any response (52% versus 25%, OR 3.23 (95% CI: 1.21-8.64), P = 0.01). Seventy-two patients received GC (n = 41) or MVAC (n = 31). CR was achieved in 29% and 22% of GC and MVAC patients, respectively (multivariate OR 0.39, 95% CI 0.10-1.58). Any response (≤pT1) was achieved in 56% of GC and 45% of MVAC patients (multivariate O...
European Urology Supplements, 2003
2014 IEEE International Ultrasonics Symposium, 2014
Kidney stones have been shown to exhibit a &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;a... more Kidney stones have been shown to exhibit a &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;twinkling artifact&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; (TA) under Color-Doppler ultrasound. Although this technique has better specificity than conventional Bmode imaging, it has lower sensitivity. To improve the overall performance of using TA as a diagnostic tool, Doppler output parameters were optimized in-vitro. The collected data supports a previous hypothesis that TA is caused by random oscillations of micron sized bubbles trapped in the cracks and crevices of kidney stones. A set of optimized parameters were implemented such that that the MI &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp; TI remained within the FDA approved limits. Several clinical kidney scans were performed with the optimized settings and were able to detect stones with improved SNR relative to the default settings.