Mark Levental - Academia.edu (original) (raw)

Papers by Mark Levental

Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine, 2002

... Mark Levental, MD,; Dolores H. Pretorius, MD,; Angela L. Scioscia, MD,; Khaldon Jundi, MD,; D... more ... Mark Levental, MD,; Dolores H. Pretorius, MD,; Angela L. Scioscia, MD,; Khaldon Jundi, MD,; Donna Wallace, MD and; Nancy E. Budorick, MD. ... Abstract/FREE Full Text. ↵ Muller F, Dommergues M, Aubry MC, Simon-Bouy B, Gautier E, Oury JF, Narcy F. Hyperechogenic fetal ...

Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine, 2000

... Long terme. ; Mifépristone. ; Diagnostic. ; Sémiologie. ; Echographie. ; Dose forte. ; Homme.... more ... Long terme. ; Mifépristone. ; Diagnostic. ; Sémiologie. ; Echographie. ; Dose forte. ; Homme. ; Exploration ultrason. ; Mots-clés espagnols / Spanish Keywords. Pólipo. ; Endometrio. ; Estudio caso. ; Hembra. ; Adulto. ; Largo plazo. ; Mifepristona. ; Diagnóstico. ; Semiología. ; Ecografía ...

Journal of otolaryngology - head & neck surgery = Le Journal d'oto-rhino-laryngologie et de chirurgie cervico-faciale, Jan 31, 2015

Accurate pre-operative imaging of parathyroid adenomas (PAs) is essential for successful minimall... more Accurate pre-operative imaging of parathyroid adenomas (PAs) is essential for successful minimally invasive surgery; however, rates of non-localizing PAs can be as high as 18 %. Multiphasic dual-energy CT (DECT) has the potential to increase accuracy of PA detection by enabling creation of paired material maps and spectral tissue characterization. This study prospectively evaluated the utility of 3-phase DECT for PA identification in patients with failed localizatio n via standard imaging. Patients with primary hyperparathyroidism and non-localizing PAs underwent a 3 phase post-contrast DECT scan acquired at 25, 55, and 85 s. The scans were prospectively evaluated by two head and neck radiologists. Pre-operative localization was compared to intraoperative localization and final histopathology. A post-hoc DECT spectral density characterization was performed on pathologically-proven PAs. Out of 29 patients with primary hyperparathyroidism and non-localized PAs, DECT identified candida...

PURPOSE To assess whether virtual laryngoscopy (VL) provides adequate visualization of a set of 2... more PURPOSE To assess whether virtual laryngoscopy (VL) provides adequate visualization of a set of 21 predetermined laryngeal structures and whether it is sensitive and accurate in evaluating laryngeal lesions with correlation to fiberoptic laryngoscopy (FL). METHOD AND MATERIALS We retrospectively identified a total of 47 patients who underwent fiberoptic laryngoscopy (FL) and helical CT-scan imaging at our institutions between Dec 2005 and Aug 2007 for evaluation of laryngeal cancer. From this set, 3D virtual laryngoscopy images were reconstructed for analysis. RESULTS There was excellent visualization of the glottic and subglottic structures on virtual laryngoscopy (89 - 100% depending on the landmark) on virtual laryngoscopy. This was comparable to flexible laryngoscopy where ten percent (10%) of the flexible laryngoscopy exams reported varying limitations in identifying the true vocal cords and subglottic region due to obstructing masses or because the patient used his/her false v...

Journal of otolaryngology - head & neck surgery = Le Journal d'oto-rhino-laryngologie et de chirurgie cervico-faciale

To determine the most common location of parathyroid adenomas. Data from 147 patients who underwe... more To determine the most common location of parathyroid adenomas. Data from 147 patients who underwent parathyroidectomy for primary hyperparathyroidism in Montreal at a McGill University teaching hospital between January 2001 and January 2008 were reviewed retrospectively. Patients with histopathologic confirmation of parathyroid hyperplasia were excluded from the study (n = 26). The 121 patients with confirmed adenomas were grouped according to the locations of the tumour into right superior, right inferior, left superior, left inferior, and ectopic. The left inferior parathyroid glands were the most common site of adenomas. This was the case for 50 patients (41.32% [mean 0.41; 95% CI 0.324-0.506]). The right inferior parathyroid glands were the site in 40 patients (33.06% [mean 0.33; 95% CI 0.248-0.422]). The remainder of the adenomas were distributed as follows: the left superior in 19 patients (15.7% [mean 0.157; 95% CI 0.097-0.234]), the right superior in 10 patients (8.26% [mean...

Clinical neuropharmacology

Multiple sclerosis (MS) is an autoimmune disorder of the central nervous system where inflammatio... more Multiple sclerosis (MS) is an autoimmune disorder of the central nervous system where inflammation and neurodegeneration play key roles. Mounting evidence implicates oxidative stress in the development of irreversible neuronal and glial injury in this condition. N-acetylcysteine (NAC) is a sulfhydryl amino acid derivative with antioxidant and antiapoptotic properties. Administration of NAC to mice attenuated the induction of or improved experimental autoimmune encephalomyelitis (an MS model). We performed an open-label study to explore the tolerability and safety of the combination of glatiramer acetate (GA) and NAC in patients with relapsing-remitting multiple sclerosis at the outpatient MS clinics of the Jewish General Hospital and Hôpital Charles Lemoyne, Montreal, Canada. Seven patients with relapsing-remitting multiple sclerosis with at least one T1 gadolinium-enhancing lesion on screening magnetic resonance imaging were recruited. Treatment consisted of a 10-week run-in period...

World Journal of Urology, 2015

Prostate cancer (PCa) diagnosis relies on clinical suspicion leading to systematic transrectal ul... more Prostate cancer (PCa) diagnosis relies on clinical suspicion leading to systematic transrectal ultrasound-guided biopsy (TRUSGB). Multiparametric magnetic resonance imaging (mpMRI) allows for targeted biopsy of suspicious areas of the prostate instead of random 12-core biopsy. This method has been shown to be more accurate in detecting significant PCa. However, the precise spatial accuracy of cognitive targeting is unknown. Consecutive patients undergoing mpMRI-targeted TRUSGB with cognitive registration (MRTB-COG) followed by robot-assisted radical prostatectomy were included in the present analysis. The regions of interest (ROIs) involved by the index lesion reported on mpMRI were subsequently targeted by two experienced urologists using the cognitive approach. The 27 ROIs were used as spatial reference. Mapping on radical prostatectomy specimen was used as reference to determine true-positive mpMRI findings. Per core correlation analysis was performed. Forty patients were included. Overall, 40 index lesions involving 137 ROIs (mean ROIs per index lesion 3.43) were identified on MRI. After correlating these findings with final pathology, 117 ROIs (85 %) were considered as true-positive lesions. A total of 102 biopsy cores directed toward such true-positive ROIs were available for final analysis. Cognitive targeted biopsy hit the target in 82 % of the cases (84/102). The only identified risk factor for missing the target was an anterior situated ROI (p = 0.01). In experienced hands, cognitive MRTB-COG allows for an accuracy of 82 % in hitting the correct target, given that it is a true-positive lesion. Anterior tumors are less likely to be successfully targeted.

Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine, 1998

Thirty-one high-risk patients (16 to 35 weeks' gestation) underwent two-dimensional and three... more Thirty-one high-risk patients (16 to 35 weeks' gestation) underwent two-dimensional and three-dimensional ultrasonography to compare two-dimensional and non-cardiac-gated three-dimensional ultrasonography of the normal fetal heart. After normal two-dimensional studies, three-dimensional sonographic volumes were acquired without cardiac gating in transverse and longitudinal planes. Standard cardiac views were derived from three-dimensional data, analyzed, and rated as follows: (1) not identifiable, (2) identifiable but inadequate for diagnosis, (3) adequate, and (4) excellent. Two-dimensional ultrasonography demonstrated better yields of diagnostically acceptable images of basic echocardiographic views (four-chamber view, 100% for two-dimensional sonography versus 10 to 71% for three-dimensional sonography; right ventricular outflow tract, 42% for two-dimensional versus 6 to 26% for three-dimensional ultrasonography; left ventricular outflow tract, 71% for two-dimensional versus ...

The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques, 2006

World Journal of Urology, 2013

To assess the impact of ultrasound probe (end fire vs. side fire) during MRI-targeted prostate bi... more To assess the impact of ultrasound probe (end fire vs. side fire) during MRI-targeted prostate biopsy using cognitive fusion. Inclusion criteria were as follows: consecutive patients undergoing prostate biopsies after multiparametric MRI; no PSA above 10 ng/ml; no clinical bulking disease; MRI areas suspicious for malignancy. From January 2011 to December 2012, 91 patients were included. A standard 10 TRUS-guided biopsy protocol plus 2 targeted biopsies at any MRI lesion was used. Patient's characteristics, MRI findings, and pathology evaluations were compared between the two groups. Mean patient age and PSA were 63 years and 5.95 ng/ml, respectively. The median number of MRI lesions was 2, and the mean volume of the index lesion was 0.64 cc. The overall PCa detection rate was 58.2 %. The MRI scoring system was significantly predictive for PCa detection and aggressiveness (p < 0.001). There was a not statistically significant trend toward greater PCa detection rate (+23 %) in the end-fire cohort (p = 0.235). The PCa detection rate is significantly improved by 1.7-fold in case of MRI score 4-5 lesion as compared to MRI score 3 lesion (p = 0.031) when using the end-fire probe. Conversely, the MRI score does not significantly influence the detection rate in the side-fire group (p = 0.250). The improvement in the PCa detection rate by the end-fire probe was predominantly reported in anterior and of apical peripheral MRI lesions. In case of high MRI score lesions, the PCa detection rate is significantly improved when using end-firing, particularly in case of anterior and apical peripheral lesions.

Journal of Robotic Surgery, 2010

Operative and peri-operative outcomes, complications, and cost for radical hysterectomy for cervi... more Operative and peri-operative outcomes, complications, and cost for radical hysterectomy for cervical cancer with negative sentinel nodes have been compared for robotics and laparotomy. Forty patients underwent radical hysterectomy with/out bilateral salpingo-oophorectomy, for early-stage cervical cancer. All cases were performed by one of two surgeons, at a single institution (16 robotic, 24 laparotomy). The data for the robotic group were collected prospectively and compared with data for a historic cohort who underwent laparotomy. The data included demographics and peri-operative variables including operative time, estimated blood loss, lymph node count, hospital stay, and complications. Additionally, real direct hospital cost was compared for both modalities. Patients undergoing robotic radical hysterectomy experienced longer operative time than the laparotomy cohort (351 min vs. 283 min P = 0.0001). Estimated blood loss was significantly lower for the robotic cohort than for the laparotomy cohort (106 ml vs. 546 ml P < 0.0001). The minor complication rate was lower in the robotic cohort than for laparotomy (19% vs. 63% P = 0.003). Average hospital stay for the robotic patients was significantly shorter than for those undergoing laparotomy (1.9 days versus 7.2 days, P < 0.0001). Lymph node retrieval did not differ between the two groups (robotic 15 nodes, laparotomy 13 nodes). The total average peri-operative costs for radical hysterectomy with lymphadenectomy completed via laparotomy was CAN $11,764 ± 6,790, and for robotic assistance 8,183 ± 1,089 (P = 0.002). When amortization of the robot was included, there remained a trend in favor of the robotic approach, but it did not reach statistical significance. Whereas robotics takes longer to perform than traditional laparotomy, it provides the patient with a shorter hospital stay, less need for pain medications, and reduced peri-operative morbidity. In addition real average hospital costs tend to be lower.

British Journal of Radiology, 2006

ANZ Journal of Surgery, 2005

Annals of Diagnostic Pathology, 2007

The American Journal of Emergency Medicine, 2009

Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine, 2002

... Mark Levental, MD,; Dolores H. Pretorius, MD,; Angela L. Scioscia, MD,; Khaldon Jundi, MD,; D... more ... Mark Levental, MD,; Dolores H. Pretorius, MD,; Angela L. Scioscia, MD,; Khaldon Jundi, MD,; Donna Wallace, MD and; Nancy E. Budorick, MD. ... Abstract/FREE Full Text. ↵ Muller F, Dommergues M, Aubry MC, Simon-Bouy B, Gautier E, Oury JF, Narcy F. Hyperechogenic fetal ...

Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine, 2000

... Long terme. ; Mifépristone. ; Diagnostic. ; Sémiologie. ; Echographie. ; Dose forte. ; Homme.... more ... Long terme. ; Mifépristone. ; Diagnostic. ; Sémiologie. ; Echographie. ; Dose forte. ; Homme. ; Exploration ultrason. ; Mots-clés espagnols / Spanish Keywords. Pólipo. ; Endometrio. ; Estudio caso. ; Hembra. ; Adulto. ; Largo plazo. ; Mifepristona. ; Diagnóstico. ; Semiología. ; Ecografía ...

Journal of otolaryngology - head & neck surgery = Le Journal d'oto-rhino-laryngologie et de chirurgie cervico-faciale, Jan 31, 2015

Accurate pre-operative imaging of parathyroid adenomas (PAs) is essential for successful minimall... more Accurate pre-operative imaging of parathyroid adenomas (PAs) is essential for successful minimally invasive surgery; however, rates of non-localizing PAs can be as high as 18 %. Multiphasic dual-energy CT (DECT) has the potential to increase accuracy of PA detection by enabling creation of paired material maps and spectral tissue characterization. This study prospectively evaluated the utility of 3-phase DECT for PA identification in patients with failed localizatio n via standard imaging. Patients with primary hyperparathyroidism and non-localizing PAs underwent a 3 phase post-contrast DECT scan acquired at 25, 55, and 85 s. The scans were prospectively evaluated by two head and neck radiologists. Pre-operative localization was compared to intraoperative localization and final histopathology. A post-hoc DECT spectral density characterization was performed on pathologically-proven PAs. Out of 29 patients with primary hyperparathyroidism and non-localized PAs, DECT identified candida...

PURPOSE To assess whether virtual laryngoscopy (VL) provides adequate visualization of a set of 2... more PURPOSE To assess whether virtual laryngoscopy (VL) provides adequate visualization of a set of 21 predetermined laryngeal structures and whether it is sensitive and accurate in evaluating laryngeal lesions with correlation to fiberoptic laryngoscopy (FL). METHOD AND MATERIALS We retrospectively identified a total of 47 patients who underwent fiberoptic laryngoscopy (FL) and helical CT-scan imaging at our institutions between Dec 2005 and Aug 2007 for evaluation of laryngeal cancer. From this set, 3D virtual laryngoscopy images were reconstructed for analysis. RESULTS There was excellent visualization of the glottic and subglottic structures on virtual laryngoscopy (89 - 100% depending on the landmark) on virtual laryngoscopy. This was comparable to flexible laryngoscopy where ten percent (10%) of the flexible laryngoscopy exams reported varying limitations in identifying the true vocal cords and subglottic region due to obstructing masses or because the patient used his/her false v...

Journal of otolaryngology - head & neck surgery = Le Journal d'oto-rhino-laryngologie et de chirurgie cervico-faciale

To determine the most common location of parathyroid adenomas. Data from 147 patients who underwe... more To determine the most common location of parathyroid adenomas. Data from 147 patients who underwent parathyroidectomy for primary hyperparathyroidism in Montreal at a McGill University teaching hospital between January 2001 and January 2008 were reviewed retrospectively. Patients with histopathologic confirmation of parathyroid hyperplasia were excluded from the study (n = 26). The 121 patients with confirmed adenomas were grouped according to the locations of the tumour into right superior, right inferior, left superior, left inferior, and ectopic. The left inferior parathyroid glands were the most common site of adenomas. This was the case for 50 patients (41.32% [mean 0.41; 95% CI 0.324-0.506]). The right inferior parathyroid glands were the site in 40 patients (33.06% [mean 0.33; 95% CI 0.248-0.422]). The remainder of the adenomas were distributed as follows: the left superior in 19 patients (15.7% [mean 0.157; 95% CI 0.097-0.234]), the right superior in 10 patients (8.26% [mean...

Clinical neuropharmacology

Multiple sclerosis (MS) is an autoimmune disorder of the central nervous system where inflammatio... more Multiple sclerosis (MS) is an autoimmune disorder of the central nervous system where inflammation and neurodegeneration play key roles. Mounting evidence implicates oxidative stress in the development of irreversible neuronal and glial injury in this condition. N-acetylcysteine (NAC) is a sulfhydryl amino acid derivative with antioxidant and antiapoptotic properties. Administration of NAC to mice attenuated the induction of or improved experimental autoimmune encephalomyelitis (an MS model). We performed an open-label study to explore the tolerability and safety of the combination of glatiramer acetate (GA) and NAC in patients with relapsing-remitting multiple sclerosis at the outpatient MS clinics of the Jewish General Hospital and Hôpital Charles Lemoyne, Montreal, Canada. Seven patients with relapsing-remitting multiple sclerosis with at least one T1 gadolinium-enhancing lesion on screening magnetic resonance imaging were recruited. Treatment consisted of a 10-week run-in period...

World Journal of Urology, 2015

Prostate cancer (PCa) diagnosis relies on clinical suspicion leading to systematic transrectal ul... more Prostate cancer (PCa) diagnosis relies on clinical suspicion leading to systematic transrectal ultrasound-guided biopsy (TRUSGB). Multiparametric magnetic resonance imaging (mpMRI) allows for targeted biopsy of suspicious areas of the prostate instead of random 12-core biopsy. This method has been shown to be more accurate in detecting significant PCa. However, the precise spatial accuracy of cognitive targeting is unknown. Consecutive patients undergoing mpMRI-targeted TRUSGB with cognitive registration (MRTB-COG) followed by robot-assisted radical prostatectomy were included in the present analysis. The regions of interest (ROIs) involved by the index lesion reported on mpMRI were subsequently targeted by two experienced urologists using the cognitive approach. The 27 ROIs were used as spatial reference. Mapping on radical prostatectomy specimen was used as reference to determine true-positive mpMRI findings. Per core correlation analysis was performed. Forty patients were included. Overall, 40 index lesions involving 137 ROIs (mean ROIs per index lesion 3.43) were identified on MRI. After correlating these findings with final pathology, 117 ROIs (85 %) were considered as true-positive lesions. A total of 102 biopsy cores directed toward such true-positive ROIs were available for final analysis. Cognitive targeted biopsy hit the target in 82 % of the cases (84/102). The only identified risk factor for missing the target was an anterior situated ROI (p = 0.01). In experienced hands, cognitive MRTB-COG allows for an accuracy of 82 % in hitting the correct target, given that it is a true-positive lesion. Anterior tumors are less likely to be successfully targeted.

Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine, 1998

Thirty-one high-risk patients (16 to 35 weeks' gestation) underwent two-dimensional and three... more Thirty-one high-risk patients (16 to 35 weeks' gestation) underwent two-dimensional and three-dimensional ultrasonography to compare two-dimensional and non-cardiac-gated three-dimensional ultrasonography of the normal fetal heart. After normal two-dimensional studies, three-dimensional sonographic volumes were acquired without cardiac gating in transverse and longitudinal planes. Standard cardiac views were derived from three-dimensional data, analyzed, and rated as follows: (1) not identifiable, (2) identifiable but inadequate for diagnosis, (3) adequate, and (4) excellent. Two-dimensional ultrasonography demonstrated better yields of diagnostically acceptable images of basic echocardiographic views (four-chamber view, 100% for two-dimensional sonography versus 10 to 71% for three-dimensional sonography; right ventricular outflow tract, 42% for two-dimensional versus 6 to 26% for three-dimensional ultrasonography; left ventricular outflow tract, 71% for two-dimensional versus ...

The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques, 2006

World Journal of Urology, 2013

To assess the impact of ultrasound probe (end fire vs. side fire) during MRI-targeted prostate bi... more To assess the impact of ultrasound probe (end fire vs. side fire) during MRI-targeted prostate biopsy using cognitive fusion. Inclusion criteria were as follows: consecutive patients undergoing prostate biopsies after multiparametric MRI; no PSA above 10 ng/ml; no clinical bulking disease; MRI areas suspicious for malignancy. From January 2011 to December 2012, 91 patients were included. A standard 10 TRUS-guided biopsy protocol plus 2 targeted biopsies at any MRI lesion was used. Patient's characteristics, MRI findings, and pathology evaluations were compared between the two groups. Mean patient age and PSA were 63 years and 5.95 ng/ml, respectively. The median number of MRI lesions was 2, and the mean volume of the index lesion was 0.64 cc. The overall PCa detection rate was 58.2 %. The MRI scoring system was significantly predictive for PCa detection and aggressiveness (p < 0.001). There was a not statistically significant trend toward greater PCa detection rate (+23 %) in the end-fire cohort (p = 0.235). The PCa detection rate is significantly improved by 1.7-fold in case of MRI score 4-5 lesion as compared to MRI score 3 lesion (p = 0.031) when using the end-fire probe. Conversely, the MRI score does not significantly influence the detection rate in the side-fire group (p = 0.250). The improvement in the PCa detection rate by the end-fire probe was predominantly reported in anterior and of apical peripheral MRI lesions. In case of high MRI score lesions, the PCa detection rate is significantly improved when using end-firing, particularly in case of anterior and apical peripheral lesions.

Journal of Robotic Surgery, 2010

Operative and peri-operative outcomes, complications, and cost for radical hysterectomy for cervi... more Operative and peri-operative outcomes, complications, and cost for radical hysterectomy for cervical cancer with negative sentinel nodes have been compared for robotics and laparotomy. Forty patients underwent radical hysterectomy with/out bilateral salpingo-oophorectomy, for early-stage cervical cancer. All cases were performed by one of two surgeons, at a single institution (16 robotic, 24 laparotomy). The data for the robotic group were collected prospectively and compared with data for a historic cohort who underwent laparotomy. The data included demographics and peri-operative variables including operative time, estimated blood loss, lymph node count, hospital stay, and complications. Additionally, real direct hospital cost was compared for both modalities. Patients undergoing robotic radical hysterectomy experienced longer operative time than the laparotomy cohort (351 min vs. 283 min P = 0.0001). Estimated blood loss was significantly lower for the robotic cohort than for the laparotomy cohort (106 ml vs. 546 ml P < 0.0001). The minor complication rate was lower in the robotic cohort than for laparotomy (19% vs. 63% P = 0.003). Average hospital stay for the robotic patients was significantly shorter than for those undergoing laparotomy (1.9 days versus 7.2 days, P < 0.0001). Lymph node retrieval did not differ between the two groups (robotic 15 nodes, laparotomy 13 nodes). The total average peri-operative costs for radical hysterectomy with lymphadenectomy completed via laparotomy was CAN $11,764 ± 6,790, and for robotic assistance 8,183 ± 1,089 (P = 0.002). When amortization of the robot was included, there remained a trend in favor of the robotic approach, but it did not reach statistical significance. Whereas robotics takes longer to perform than traditional laparotomy, it provides the patient with a shorter hospital stay, less need for pain medications, and reduced peri-operative morbidity. In addition real average hospital costs tend to be lower.

British Journal of Radiology, 2006

ANZ Journal of Surgery, 2005

Annals of Diagnostic Pathology, 2007

The American Journal of Emergency Medicine, 2009