Tasha Ellchuk - Academia.edu (original) (raw)

Papers by Tasha Ellchuk

Research paper thumbnail of Canadian Residents' Corner / Coin canadien des residents en radiology Answer to Case of the Month #147 Strangulated Small Bowel Within an Omental Hernia

Research paper thumbnail of Evaluation of the Modified Barium Swallow Study Conducted With and Without Radiologist Supervision: A Pre- and Post-Observational Study

Canadian Association of Radiologists Journal, 2021

Purpose: Assess quality metrics of modified barium swallow studies (MBSS) with and without a radi... more Purpose: Assess quality metrics of modified barium swallow studies (MBSS) with and without a radiologist present during the procedure. Methods: Retrospective review of MBSS performed on adult inpatients at a tertiary care hospital 6-months pre- and post-institutional change from having to not having a radiologist present during the examination. Factors assessed included: fluoroscopy time; study duration; number of cine loops; number of images; efficiency of collimation (using a 5-point scoring system); time to final report; radiologist-speech language pathologist report disagreement; and recalls for inadequate studies. Statistical analysis was via Welch’s t-test and a test of proportions for continuous and count data under the normal approximation. Results: 106 and 119 MBSS were analyzed from the radiologist present and radiologist absent periods, respectively. No statistically significant differences were found for: average fluoroscopy time (116.1 s vs. 126.9 s; P = 0.161); study d...

Research paper thumbnail of The Effect of Tumor Neovasculature on Functional Magnetic Resonance Imaging Blood Oxygen Level–Dependent Activation

World Neurosurgery, 2018

We report a 40-year-old patient with a large, WHO grade III oligodendroglioma in the left parieta... more We report a 40-year-old patient with a large, WHO grade III oligodendroglioma in the left parietal lobe. Presurgical planning included fMRI localization of language, motor, and somatosensory processing. The fMRI results for the motor and somatosensory tasks revealed activation in peri-lesional regions near the surgical resection, as well as deactivation in the tumour for the sensory task, suggesting that there is decreased autoregulation in the region due to the glioma. The fMRI results showed left hemisphere dominance for language, as well as activation in peri-lesional regions for all three speech tasks (i.e., word reading, picture naming, and semantic questions). In addition, the results demonstrated that the high vascularity of the lesion altered the BOLD function, resulting in false positive and false negative activation in the semantic questions and leg/foot rubbing task, respectively. Intraoperative direct cortical stimulation was conducted in the regions corresponding to the fMRI activation while the patient performed motor, sensory, and language tasks, and showed no loss of function. A follow-up fMRI scan revealed that there was no longer activation in the tumour or in peri-lesional regions, presumably due to the resection of the vascularized tumour. This case report highlights the importance of presurgical fMRI in order to inform the neurosurgical approach, but also emphasizes the need for careful interpretation of fMRI data, especially in malignant glioma cases, which can decrease autoregulation in the tumour and surrounding regions, thus affecting the fMRI BOLD signal.

Research paper thumbnail of Online TI-RADS Calculator

Open Journal of Radiology, 2018

Background: Thyroid nodules are common and fine needle aspiration (FNA) or surgery is used to ass... more Background: Thyroid nodules are common and fine needle aspiration (FNA) or surgery is used to assess for malignancy. Thyroid Imaging, Reporting and Data System (TI-RADS) use ultrasound for non-invasive risk stratification of thyroid nodules and reduce unnecessary biopsies. This project used an online calculator and education to facilitate the application of TI-RADS in clinical practice. Methods: Retrospective review defined the baseline reporting of thyroid nodule ultrasound features. Web-based resource and presentation were used to integrate TI-RADS in reporting thyroid ultrasounds and measure the improvements in comprehensive reporting of thyroid nodules and guiding management. Results: The percentage of thyroid ultrasound reporting using TI-RADS within six months increased from 0% to 27% during the project period. Reports with TI-RADS provided twice as many recommendations compared to reports without TI-RADS. Conclusion: Online TI-RADS calculator and education have successfully facilitated the integration of TI-RADS in thyroid ultrasound reporting to provide more accurate and comprehensive reports and guide management.

Research paper thumbnail of P.064 Preoperative mapping using fMRI and DTI: a multimodal approach to assessing language dominance

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 2018

Background: Language mapping is a key goal in neurosurgical planning. With the discontinuation of... more Background: Language mapping is a key goal in neurosurgical planning. With the discontinuation of the Wada test in Canada, neurosurgeons often rely on fMRI and intraoperative techniques for determining language lateralization. Recent studies have also evaluated the utility of diffusion tensor imaging (DTI) for preoperative language lateralization, but further research is needed to confirm its efficacy. We report a patient with a left frontal AVM. fMRI and DTI was used to localize language and motor functioning. Methods: The tasks included word reading, picture naming, pseudohomophones (e.g., dawg) and semantic questions. All fMRI analyses were performed using BrainVoyager. Tensors were tracked from 30-direction diffusion MR images using DSI-Studio. Results: The fMRI results revealed consistent Broca’s and Wernicke’s areas, confirming left hemisphere dominance. There was also a region of activation in the precentral gyrus near the surgical resection. The results were loaded onto the ...

Research paper thumbnail of Reorganized neural activation in motor cortex following subdural fluid collection: an fMRI and DTI study

Neurocase, Jan 24, 2017

We report a patient with a cavernous malformation involving the right lentiform nucleus. Pre-surg... more We report a patient with a cavernous malformation involving the right lentiform nucleus. Pre-surgical planning included fMRI localization of language, motor, and sensory processing, and DTI of white matter tracts. fMRI results revealed no activation near the planned resection zone. However, post-surgery the patient developed a subdural fluid collection, which applied pressure to the primary motor cortex (M1). Follow-up scans revealed that motor activation had shifted due to pressure, and then shifted to a new location after the fluid collection subsided. This case report suggests that long-term neural reorganization can occur in response to short term compression in the cortex.

Research paper thumbnail of P.082 Neural Reorganization Following Compression of the Motor Cortex: An fMRI and DTI Case Report

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 2017

Background: Functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) are n... more Background: Functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) are noninvasive and reliable tools for mapping eloquent cortex and white matter tracks prior to brain surgery. In this case, fMRI and DTI were used to inform the surgical approach in the resection of a deep cavernous malformation near the right lentiform nucleus. Post-surgery, the patient developed a fluid collection in the frontal cortex that applied pressure to M1, which led to reorganization of the motor cortex. Methods: The tasks included finger tapping, arm rubbing, and lip licking. All fMRI analyses were performed using BrainVoyager. Tensors were tracked from 20-direction diffusion MR images using DSIStudio. Results: An fMRI scan one-month pre-surgery revealed activation in M1 for the three tasks. A six-month follow-up scan revealed motor activation had been displaced by the fluid collection. A ten-month follow-up scan revealed that activation had shifted from its original location to m...

Research paper thumbnail of P.081 Using functional MRI to assess the applicability of surgery or radiosurgery for vascular malformations near eloquent cortex

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 2017

Background: Although surgery is the gold standard for treating brain arteriovenous malformations ... more Background: Although surgery is the gold standard for treating brain arteriovenous malformations (AVMs), surgical techniques may not be suitable if the AVM is located in eloquent regions of the brain, such as the motor cortex. An alternative method for these cases is stereotactic radiosurgery. Localization of the motor cortex using functional magnetic resonance imaging (fMRI) is useful for helping the neurosurgeon determine which type of surgery is appropriate. We report a patient with a left frontal AVM near the motor cortex. fMRI was requested to localize motor functioning. Methods: The tasks included bilateral finger tapping, arm rubbing against the scanner, and abdominal tightening. All fMRI analyses were performed using BrainVoyager. Results: The fMRI results revealed that finger tapping and arm rubbing activated the precentral gyrus and supplementary motor area, and abdominal tightening activated the paracentral gyrus. These regions of activation were shown to be just posterio...

Research paper thumbnail of Epidemiology of spinal infections: retrospective review of the patients with osteomyelitis, discitis, and epidural abscesses

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 2015

Background:Spinal infections are one of the most difficult, complex, and multi-disciplinary healt... more Background:Spinal infections are one of the most difficult, complex, and multi-disciplinary health conditions. The purpose of this paper was to gather demographic information of the patients with spinal infections and to identify factors that would influence their management.Methods:Retrospective chart review of 146 adult patients with osteomyelitis, discitis or epidural abscesses admitted to the Royal University Hospital, Saskatchewan, from 2007-2014.Results:Patient demographics included 59% male, 41% female, mean age 53 years. 36% of patients required surgery, 44% were IV drug users, and 71% were managed by surgeons. Presence of a neurological deficit, higher white blood cell count, and longer hospital admission, in relation to poor outcomes, were statistically significant. Higher age and shorter duration between onset of symptoms and admission showed a trend toward a poorer outcome. Epidural abscess and presence of a neurological deficit are variables isolated as being statistica...

Research paper thumbnail of • Can hippocampus be spared in patients with small cell lung carcinoma (SCLC) during cranial radiation therapy (CRT)?

Research paper thumbnail of Prevalence of extracranial venous narrowing on catheter venography in people with multiple sclerosis, their siblings, and unrelated healthy controls: a blinded, case-control study

Journal of Vascular Surgery, 2014

EVAR and open repair. In the current study, the authors sought to analyze the cost-effectiveness ... more EVAR and open repair. In the current study, the authors sought to analyze the cost-effectiveness and cost-utility of EVAR compared with a standard open repair in the treatment of rAAA, with costs per 30-day and 6-month survival as outcome parameters. Resource use was determined from the Amsterdam Acute Aneurysm trial data. Analysis was performed from a provider perspective. All costs were calculated as if patients had been treated in the same teaching hospital (Onze Lieve Vrouwe Gasthuis). The study randomized 116 patients. The 30-day mortality was 21% after EVAR and 25% after open repair, for an absolute risk reduction of 4.4% (95% confidence interval [CI], À11.0% to 19.7%). At 6 months, the total mortality rate for EVAR was 28% compared with 31% for those assigned to open repair (absolute risk reduction, 2.4%; 95% CI, À14.2% to 19.0%). The mean cost difference between EVAR and OR was €5306 (95% CI, À€1854 to €12,659) at 30 days and €10,189 (95% CI, e€2477 to €24,506) at 6 months. The incremental cost-effectiveness ratio per prevented death was €120,591 at 30 days and €424,542 at 6 months. There was no significant difference in quality of life between EVAR and OR. EVAR was not superior regarding cost-utility, either. In this study, the mean costs of the EVAR group were substantially raised by eight patients who required conversion to open repair. At 6 months, the mean difference between the converted and nonconverted groups was €19,981. The total costs required to save one person's life with EVAR was €120,446. At 6 months, this leads to a number needed to treat of 41.7 patients at €424,881 per life saved. Comment: Overall, the Amsterdam Ruptured Aneurysm Study has indicated that EVAR for treatment of rAAA is associated with a slightly lower mortality rate but a considerably higher cost. The paper raises the interesting point: At what point are advances in medical technology affordable, and at what point do they become cost-prohibitive?

Research paper thumbnail of Answer to Case of the Month #147

Canadian Association of Radiologists Journal, 2009

A 63-year-old woman presents to the emergency department with acute-onset epigastric pain. Physic... more A 63-year-old woman presents to the emergency department with acute-onset epigastric pain. Physical examination reveals an unstable blood pressure, and findings of peritonitis. There is no history of a previous or chronic illness. Past surgical history is notable for a hysterectomy. Laboratory evaluation is unremarkable with the exception of an increased lactate level. Enhanced computed tomography (CT) examination of the abdomen/pelvis was performed (Figures 1e5). Diagnosis Strangulated small bowel within an internal (omental) hernia. Incidentally noted nonrotation of the bowel.

Research paper thumbnail of Case of the Month #147

Canadian Association of Radiologists Journal, 2009

A 63-year-old woman presents to the emergency department with acute-onset epigastric pain. Physic... more A 63-year-old woman presents to the emergency department with acute-onset epigastric pain. Physical examination reveals an unstable blood pressure, and findings of peritonitis.

Research paper thumbnail of P.134 Spinal epidural abscess associated with septic facet joints-one center experience

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 2016

Background:Infection to the facet joints has been reported sporadically but the significance of t... more Background:Infection to the facet joints has been reported sporadically but the significance of this type of infection has not been clarified. In our study on spine infection, we identified the cases of spinal epidural abscess with septic joints and was able to compare to cases of epidural abscess with discitis and osteomyelitis.Methods:Between 2007 and 2014, we experienced 176 cases of spine infection including discitis, osteomyelitis and epidural abscess. Retrospective review of the clinical data and radiological findings was performed. Among 176 cases, 80 patients had epidural abscess. They were divided to two groups, one with septic joint and the other with discitis and osteomyelitis.Results:23 patients were found to have septic joints with epidural abscess based on the MRI findings. Mean age was 45.5. 15 of 23 patients (65%) required surgery and all treated with laminectomy. 78% had a good neurological outcome.57 patients had epidural abscess with discitis and osteomyelitis. Me...

Research paper thumbnail of Phosphatidylinositol 3-Kinase is required for adherens junction-dependent mammary epithelial cell spheroid formation

Differentiation, 2000

Adherens junctions facilitate and maintain epithelial cell-cell adhesion. This is true of mammary... more Adherens junctions facilitate and maintain epithelial cell-cell adhesion. This is true of mammary epithelial cells, both in two dimensional monolayers and in three-dimensional basement membrane cultures. Using the immortalized, functional mouse mammary epithelial scp2 cell line, we found that pharmacological inhibition of phosphatidylinositol 3-kinase (PI3-kinase) disrupted adherens junctions. In monolayers, this disruption was associated with decreased E-cadherin and b-catenin at sites of cell-cell contact and decreased association of both proteins with the cytoskeleton. Changes in the distribution of f-actin after PI3-kinase inhibition suggest that this disruption of adherens junctions may be mediated by alterations to the cytoskeleton. In basement membrane cultures, PI3-kinase inhibition reversibly prevented adherens junction-dependent spheroid formation and differentiative milk protein gene expression, both in scp2 cells and in a second mouse mammary epithelial cell line, EpH4. Decreasing the calcium concentration in the culture medium produced similar, although less dramatic, phenotypic effects. These data indicate that adherens junctions contribute, at least in part, to the efficient induction of basement membrane-dependent differentiation of mammary epithelial cells.

Research paper thumbnail of Pre-Surgical Integration of fMRI and DTI of the Sensorimotor System in Transcortical Resection of a High-Grade Insular Astrocytoma

Frontiers in Integrative Neuroscience, 2016

Herein we report on a patient with a WHO Grade III astrocytoma in the right insular region in clo... more Herein we report on a patient with a WHO Grade III astrocytoma in the right insular region in close proximity to the internal capsule who underwent a right frontotemporal craniotomy. Total gross resection of insular gliomas remains surgically challenging based on the possibility of damage to the corticospinal tracts. However, maximizing the extent of resection has been shown to decrease future adverse outcomes. Thus, the goal of such surgeries should focus on maximizing extent of resection while minimizing possible adverse outcomes. In this case, pre-surgical planning included integration of functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), to localize motor and sensory pathways. Novel fMRI tasks were individually developed for the patient to maximize both somatosensory and motor activation simultaneously in areas in close proximity to the tumor. Information obtained was used to optimize resection trajectory and extent, facilitating gross total resection of the astrocytoma. Across all three motor-sensory tasks administered, fMRI revealed an area of interest just superior and lateral to the astrocytoma. Further, DTI analyses showed displacement of the corona radiata around the superior dorsal surface of the astrocytoma, extending in the direction of the activation found using fMRI. Taking into account these results, a transcortical superior temporal gyrus surgical approach was chosen in order to avoid the area of interest identified by fMRI and DTI. Total gross resection was achieved and minor post-surgical motor and sensory deficits were temporary. This case highlights the utility of comprehensive pre-surgical planning, including fMRI and DTI, to maximize surgical outcomes on a case-by-case basis.

Research paper thumbnail of Presurgical language mapping in epilepsy: Using fMRI of reading to identify functional reorganization in a patient with long-standing temporal lobe epilepsy

Epilepsy & Behavior Case Reports, 2016

Research paper thumbnail of Attentional Network Differences Between Migraineurs and Non-migraine Controls: fMRI Evidence

Brain Topography, 2015

Migraine is a headache disorder characterized by sensitivity to light and sound. Recent research ... more Migraine is a headache disorder characterized by sensitivity to light and sound. Recent research has revealed abnormal visual-spatial attention in migraineurs in between headache attacks. Here, we ask whether these attentional abnormalities can be attributed to specific regions of the known attentional network to help characterize the abnormalities in migraine. Specifically, the ventral frontoparietal network of attention is involved with assessing the behavioural relevance of unattended stimuli. Given the decreased suppression of unattended stimuli reported in migraineurs, we hypothesized that migraineurs would have abnormal processing in the ventral portion of the frontoparietal network of attention. To address this, we used functional magnetic resonance imaging to assess the attentional control networks during visual spatial-orienting tasks in migraineurs (N = 16) as compared to non-migraine controls (N = 16). We employed two visual orienting paradigms with target discrimination tasks: (1) voluntary orienting to central arrow cues, and (2) reflexive orienting to peripheral flash cues. While both groups showed activation in the key areas of attentional processing networks, migraineurs showed less activation than non-migraine controls in a key area of the ventral frontoparietal network of attention, the right temporal parietal junction (rTPJ), during both voluntary and reflexive visual spatial orienting. Given the role of rTPJ is to assess the visual environment for behaviorally relevant sensory stimuli outside the focus of attention and signal other attentional areas to reorient attention to behaviorally salient stimuli, our findings fit with previous research showing that migraineurs lack suppression of unattended events and have heightened orienting to sudden onset stimuli in peripheral locations.

Research paper thumbnail of • Can hippocampus be spared in patients with small cell lung carcinoma (SCLC) during cranial radiation therapy (CRT)?

Although CRT is a standard therapy for prevention and treatment of brain metastases (BM) in patie... more Although CRT is a standard therapy for prevention and treatment of brain metastases (BM) in patients with SCLC, neurocognitive impairment (NI) following therapeutic whole brain radiation treatment (WBRT) or prophylactic cranial irradiation (PCI) is a major problem & can cause impairment in quality of life. A RTOG study is assessing various outcomes by avoiding the hippocampus (AH) during WBRT in different malignancies. The estimated risk of hippocampal avoidance region metastases (HM) in patients with SCLC before & after WBRT/PCI is not known. AH during CRT may delay the onset of NI in such patients. Our study aims to determine risk of HM in patients with SCLC and to assess clinical factors correlate with it. Methods: A patients cohort of SCLC diagnosed and treated at the Saskatoon Cancer Center between 2005 and 2012 were followed. All MRI and/or CT scans were independently reviewed by a neuroradiologist. HM was defined as BM within 5 mm of hippocampus. Binary Logistic regression an...

Research paper thumbnail of Inclusion of Attentional Networks in the Pre-Surgical Neuroimaging Assessment of a Large Deep Hemispheric Cavernous Malformation: An fMRI Case Report

Cerebrovascular Diseases, 2015

Functional magnetic resonance imaging (fMRI) is a noninvasive and reliable tool for mapping eloqu... more Functional magnetic resonance imaging (fMRI) is a noninvasive and reliable tool for mapping eloquent cortex in patients prior to brain surgery. Ensuring intact perceptual and cognitive processing is a key goal for neurosurgeons, and recent research has indicated the value of including attentional network processing in pre-surgical fMRI in order to help preserve such abilities, including reading, after surgery. We report a 42-year-old patient with a large cavernous malformation, near the left basal ganglia. The lesion measured 3.8 × 1.7 × 1.8 cm. In consultation with the patient and the multidisciplinary cerebrovascular team, the decision was made to offer the patient surgical resection. The surgical resection involved planned access via the left superior parietal lobule using stereotactic location. The patient declined an awake craniotomy; therefore, direct electrocortical stimulation (ECS) could not be used for intraoperative language localization in this case. Pre-surgical planning included fMRI localization of language, motor, sensory, and attentional processing. The key finding was that both reading and attention-processing tasks revealed consistent activation of the left superior parietal lobule, part of the attentional control network, and the site of the planned surgical access. Given this information, surgical access was adjusted to avoid interference with the attentional control network. The lesion was removed via the left inferior parietal lobule. The patient had no new neurologic deficits postoperatively but did develop mild neuropathic pain in the left hand. This case report supports recent research that indicates the value of including fMRI maps of attentional tasks along with traditional language-processing tasks in preoperative planning in patients undergoing neurosurgery procedures. © 2015 S. Karger AG, Basel.

Research paper thumbnail of Canadian Residents' Corner / Coin canadien des residents en radiology Answer to Case of the Month #147 Strangulated Small Bowel Within an Omental Hernia

Research paper thumbnail of Evaluation of the Modified Barium Swallow Study Conducted With and Without Radiologist Supervision: A Pre- and Post-Observational Study

Canadian Association of Radiologists Journal, 2021

Purpose: Assess quality metrics of modified barium swallow studies (MBSS) with and without a radi... more Purpose: Assess quality metrics of modified barium swallow studies (MBSS) with and without a radiologist present during the procedure. Methods: Retrospective review of MBSS performed on adult inpatients at a tertiary care hospital 6-months pre- and post-institutional change from having to not having a radiologist present during the examination. Factors assessed included: fluoroscopy time; study duration; number of cine loops; number of images; efficiency of collimation (using a 5-point scoring system); time to final report; radiologist-speech language pathologist report disagreement; and recalls for inadequate studies. Statistical analysis was via Welch’s t-test and a test of proportions for continuous and count data under the normal approximation. Results: 106 and 119 MBSS were analyzed from the radiologist present and radiologist absent periods, respectively. No statistically significant differences were found for: average fluoroscopy time (116.1 s vs. 126.9 s; P = 0.161); study d...

Research paper thumbnail of The Effect of Tumor Neovasculature on Functional Magnetic Resonance Imaging Blood Oxygen Level–Dependent Activation

World Neurosurgery, 2018

We report a 40-year-old patient with a large, WHO grade III oligodendroglioma in the left parieta... more We report a 40-year-old patient with a large, WHO grade III oligodendroglioma in the left parietal lobe. Presurgical planning included fMRI localization of language, motor, and somatosensory processing. The fMRI results for the motor and somatosensory tasks revealed activation in peri-lesional regions near the surgical resection, as well as deactivation in the tumour for the sensory task, suggesting that there is decreased autoregulation in the region due to the glioma. The fMRI results showed left hemisphere dominance for language, as well as activation in peri-lesional regions for all three speech tasks (i.e., word reading, picture naming, and semantic questions). In addition, the results demonstrated that the high vascularity of the lesion altered the BOLD function, resulting in false positive and false negative activation in the semantic questions and leg/foot rubbing task, respectively. Intraoperative direct cortical stimulation was conducted in the regions corresponding to the fMRI activation while the patient performed motor, sensory, and language tasks, and showed no loss of function. A follow-up fMRI scan revealed that there was no longer activation in the tumour or in peri-lesional regions, presumably due to the resection of the vascularized tumour. This case report highlights the importance of presurgical fMRI in order to inform the neurosurgical approach, but also emphasizes the need for careful interpretation of fMRI data, especially in malignant glioma cases, which can decrease autoregulation in the tumour and surrounding regions, thus affecting the fMRI BOLD signal.

Research paper thumbnail of Online TI-RADS Calculator

Open Journal of Radiology, 2018

Background: Thyroid nodules are common and fine needle aspiration (FNA) or surgery is used to ass... more Background: Thyroid nodules are common and fine needle aspiration (FNA) or surgery is used to assess for malignancy. Thyroid Imaging, Reporting and Data System (TI-RADS) use ultrasound for non-invasive risk stratification of thyroid nodules and reduce unnecessary biopsies. This project used an online calculator and education to facilitate the application of TI-RADS in clinical practice. Methods: Retrospective review defined the baseline reporting of thyroid nodule ultrasound features. Web-based resource and presentation were used to integrate TI-RADS in reporting thyroid ultrasounds and measure the improvements in comprehensive reporting of thyroid nodules and guiding management. Results: The percentage of thyroid ultrasound reporting using TI-RADS within six months increased from 0% to 27% during the project period. Reports with TI-RADS provided twice as many recommendations compared to reports without TI-RADS. Conclusion: Online TI-RADS calculator and education have successfully facilitated the integration of TI-RADS in thyroid ultrasound reporting to provide more accurate and comprehensive reports and guide management.

Research paper thumbnail of P.064 Preoperative mapping using fMRI and DTI: a multimodal approach to assessing language dominance

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 2018

Background: Language mapping is a key goal in neurosurgical planning. With the discontinuation of... more Background: Language mapping is a key goal in neurosurgical planning. With the discontinuation of the Wada test in Canada, neurosurgeons often rely on fMRI and intraoperative techniques for determining language lateralization. Recent studies have also evaluated the utility of diffusion tensor imaging (DTI) for preoperative language lateralization, but further research is needed to confirm its efficacy. We report a patient with a left frontal AVM. fMRI and DTI was used to localize language and motor functioning. Methods: The tasks included word reading, picture naming, pseudohomophones (e.g., dawg) and semantic questions. All fMRI analyses were performed using BrainVoyager. Tensors were tracked from 30-direction diffusion MR images using DSI-Studio. Results: The fMRI results revealed consistent Broca’s and Wernicke’s areas, confirming left hemisphere dominance. There was also a region of activation in the precentral gyrus near the surgical resection. The results were loaded onto the ...

Research paper thumbnail of Reorganized neural activation in motor cortex following subdural fluid collection: an fMRI and DTI study

Neurocase, Jan 24, 2017

We report a patient with a cavernous malformation involving the right lentiform nucleus. Pre-surg... more We report a patient with a cavernous malformation involving the right lentiform nucleus. Pre-surgical planning included fMRI localization of language, motor, and sensory processing, and DTI of white matter tracts. fMRI results revealed no activation near the planned resection zone. However, post-surgery the patient developed a subdural fluid collection, which applied pressure to the primary motor cortex (M1). Follow-up scans revealed that motor activation had shifted due to pressure, and then shifted to a new location after the fluid collection subsided. This case report suggests that long-term neural reorganization can occur in response to short term compression in the cortex.

Research paper thumbnail of P.082 Neural Reorganization Following Compression of the Motor Cortex: An fMRI and DTI Case Report

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 2017

Background: Functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) are n... more Background: Functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) are noninvasive and reliable tools for mapping eloquent cortex and white matter tracks prior to brain surgery. In this case, fMRI and DTI were used to inform the surgical approach in the resection of a deep cavernous malformation near the right lentiform nucleus. Post-surgery, the patient developed a fluid collection in the frontal cortex that applied pressure to M1, which led to reorganization of the motor cortex. Methods: The tasks included finger tapping, arm rubbing, and lip licking. All fMRI analyses were performed using BrainVoyager. Tensors were tracked from 20-direction diffusion MR images using DSIStudio. Results: An fMRI scan one-month pre-surgery revealed activation in M1 for the three tasks. A six-month follow-up scan revealed motor activation had been displaced by the fluid collection. A ten-month follow-up scan revealed that activation had shifted from its original location to m...

Research paper thumbnail of P.081 Using functional MRI to assess the applicability of surgery or radiosurgery for vascular malformations near eloquent cortex

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 2017

Background: Although surgery is the gold standard for treating brain arteriovenous malformations ... more Background: Although surgery is the gold standard for treating brain arteriovenous malformations (AVMs), surgical techniques may not be suitable if the AVM is located in eloquent regions of the brain, such as the motor cortex. An alternative method for these cases is stereotactic radiosurgery. Localization of the motor cortex using functional magnetic resonance imaging (fMRI) is useful for helping the neurosurgeon determine which type of surgery is appropriate. We report a patient with a left frontal AVM near the motor cortex. fMRI was requested to localize motor functioning. Methods: The tasks included bilateral finger tapping, arm rubbing against the scanner, and abdominal tightening. All fMRI analyses were performed using BrainVoyager. Results: The fMRI results revealed that finger tapping and arm rubbing activated the precentral gyrus and supplementary motor area, and abdominal tightening activated the paracentral gyrus. These regions of activation were shown to be just posterio...

Research paper thumbnail of Epidemiology of spinal infections: retrospective review of the patients with osteomyelitis, discitis, and epidural abscesses

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 2015

Background:Spinal infections are one of the most difficult, complex, and multi-disciplinary healt... more Background:Spinal infections are one of the most difficult, complex, and multi-disciplinary health conditions. The purpose of this paper was to gather demographic information of the patients with spinal infections and to identify factors that would influence their management.Methods:Retrospective chart review of 146 adult patients with osteomyelitis, discitis or epidural abscesses admitted to the Royal University Hospital, Saskatchewan, from 2007-2014.Results:Patient demographics included 59% male, 41% female, mean age 53 years. 36% of patients required surgery, 44% were IV drug users, and 71% were managed by surgeons. Presence of a neurological deficit, higher white blood cell count, and longer hospital admission, in relation to poor outcomes, were statistically significant. Higher age and shorter duration between onset of symptoms and admission showed a trend toward a poorer outcome. Epidural abscess and presence of a neurological deficit are variables isolated as being statistica...

Research paper thumbnail of • Can hippocampus be spared in patients with small cell lung carcinoma (SCLC) during cranial radiation therapy (CRT)?

Research paper thumbnail of Prevalence of extracranial venous narrowing on catheter venography in people with multiple sclerosis, their siblings, and unrelated healthy controls: a blinded, case-control study

Journal of Vascular Surgery, 2014

EVAR and open repair. In the current study, the authors sought to analyze the cost-effectiveness ... more EVAR and open repair. In the current study, the authors sought to analyze the cost-effectiveness and cost-utility of EVAR compared with a standard open repair in the treatment of rAAA, with costs per 30-day and 6-month survival as outcome parameters. Resource use was determined from the Amsterdam Acute Aneurysm trial data. Analysis was performed from a provider perspective. All costs were calculated as if patients had been treated in the same teaching hospital (Onze Lieve Vrouwe Gasthuis). The study randomized 116 patients. The 30-day mortality was 21% after EVAR and 25% after open repair, for an absolute risk reduction of 4.4% (95% confidence interval [CI], À11.0% to 19.7%). At 6 months, the total mortality rate for EVAR was 28% compared with 31% for those assigned to open repair (absolute risk reduction, 2.4%; 95% CI, À14.2% to 19.0%). The mean cost difference between EVAR and OR was €5306 (95% CI, À€1854 to €12,659) at 30 days and €10,189 (95% CI, e€2477 to €24,506) at 6 months. The incremental cost-effectiveness ratio per prevented death was €120,591 at 30 days and €424,542 at 6 months. There was no significant difference in quality of life between EVAR and OR. EVAR was not superior regarding cost-utility, either. In this study, the mean costs of the EVAR group were substantially raised by eight patients who required conversion to open repair. At 6 months, the mean difference between the converted and nonconverted groups was €19,981. The total costs required to save one person's life with EVAR was €120,446. At 6 months, this leads to a number needed to treat of 41.7 patients at €424,881 per life saved. Comment: Overall, the Amsterdam Ruptured Aneurysm Study has indicated that EVAR for treatment of rAAA is associated with a slightly lower mortality rate but a considerably higher cost. The paper raises the interesting point: At what point are advances in medical technology affordable, and at what point do they become cost-prohibitive?

Research paper thumbnail of Answer to Case of the Month #147

Canadian Association of Radiologists Journal, 2009

A 63-year-old woman presents to the emergency department with acute-onset epigastric pain. Physic... more A 63-year-old woman presents to the emergency department with acute-onset epigastric pain. Physical examination reveals an unstable blood pressure, and findings of peritonitis. There is no history of a previous or chronic illness. Past surgical history is notable for a hysterectomy. Laboratory evaluation is unremarkable with the exception of an increased lactate level. Enhanced computed tomography (CT) examination of the abdomen/pelvis was performed (Figures 1e5). Diagnosis Strangulated small bowel within an internal (omental) hernia. Incidentally noted nonrotation of the bowel.

Research paper thumbnail of Case of the Month #147

Canadian Association of Radiologists Journal, 2009

A 63-year-old woman presents to the emergency department with acute-onset epigastric pain. Physic... more A 63-year-old woman presents to the emergency department with acute-onset epigastric pain. Physical examination reveals an unstable blood pressure, and findings of peritonitis.

Research paper thumbnail of P.134 Spinal epidural abscess associated with septic facet joints-one center experience

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 2016

Background:Infection to the facet joints has been reported sporadically but the significance of t... more Background:Infection to the facet joints has been reported sporadically but the significance of this type of infection has not been clarified. In our study on spine infection, we identified the cases of spinal epidural abscess with septic joints and was able to compare to cases of epidural abscess with discitis and osteomyelitis.Methods:Between 2007 and 2014, we experienced 176 cases of spine infection including discitis, osteomyelitis and epidural abscess. Retrospective review of the clinical data and radiological findings was performed. Among 176 cases, 80 patients had epidural abscess. They were divided to two groups, one with septic joint and the other with discitis and osteomyelitis.Results:23 patients were found to have septic joints with epidural abscess based on the MRI findings. Mean age was 45.5. 15 of 23 patients (65%) required surgery and all treated with laminectomy. 78% had a good neurological outcome.57 patients had epidural abscess with discitis and osteomyelitis. Me...

Research paper thumbnail of Phosphatidylinositol 3-Kinase is required for adherens junction-dependent mammary epithelial cell spheroid formation

Differentiation, 2000

Adherens junctions facilitate and maintain epithelial cell-cell adhesion. This is true of mammary... more Adherens junctions facilitate and maintain epithelial cell-cell adhesion. This is true of mammary epithelial cells, both in two dimensional monolayers and in three-dimensional basement membrane cultures. Using the immortalized, functional mouse mammary epithelial scp2 cell line, we found that pharmacological inhibition of phosphatidylinositol 3-kinase (PI3-kinase) disrupted adherens junctions. In monolayers, this disruption was associated with decreased E-cadherin and b-catenin at sites of cell-cell contact and decreased association of both proteins with the cytoskeleton. Changes in the distribution of f-actin after PI3-kinase inhibition suggest that this disruption of adherens junctions may be mediated by alterations to the cytoskeleton. In basement membrane cultures, PI3-kinase inhibition reversibly prevented adherens junction-dependent spheroid formation and differentiative milk protein gene expression, both in scp2 cells and in a second mouse mammary epithelial cell line, EpH4. Decreasing the calcium concentration in the culture medium produced similar, although less dramatic, phenotypic effects. These data indicate that adherens junctions contribute, at least in part, to the efficient induction of basement membrane-dependent differentiation of mammary epithelial cells.

Research paper thumbnail of Pre-Surgical Integration of fMRI and DTI of the Sensorimotor System in Transcortical Resection of a High-Grade Insular Astrocytoma

Frontiers in Integrative Neuroscience, 2016

Herein we report on a patient with a WHO Grade III astrocytoma in the right insular region in clo... more Herein we report on a patient with a WHO Grade III astrocytoma in the right insular region in close proximity to the internal capsule who underwent a right frontotemporal craniotomy. Total gross resection of insular gliomas remains surgically challenging based on the possibility of damage to the corticospinal tracts. However, maximizing the extent of resection has been shown to decrease future adverse outcomes. Thus, the goal of such surgeries should focus on maximizing extent of resection while minimizing possible adverse outcomes. In this case, pre-surgical planning included integration of functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), to localize motor and sensory pathways. Novel fMRI tasks were individually developed for the patient to maximize both somatosensory and motor activation simultaneously in areas in close proximity to the tumor. Information obtained was used to optimize resection trajectory and extent, facilitating gross total resection of the astrocytoma. Across all three motor-sensory tasks administered, fMRI revealed an area of interest just superior and lateral to the astrocytoma. Further, DTI analyses showed displacement of the corona radiata around the superior dorsal surface of the astrocytoma, extending in the direction of the activation found using fMRI. Taking into account these results, a transcortical superior temporal gyrus surgical approach was chosen in order to avoid the area of interest identified by fMRI and DTI. Total gross resection was achieved and minor post-surgical motor and sensory deficits were temporary. This case highlights the utility of comprehensive pre-surgical planning, including fMRI and DTI, to maximize surgical outcomes on a case-by-case basis.

Research paper thumbnail of Presurgical language mapping in epilepsy: Using fMRI of reading to identify functional reorganization in a patient with long-standing temporal lobe epilepsy

Epilepsy & Behavior Case Reports, 2016

Research paper thumbnail of Attentional Network Differences Between Migraineurs and Non-migraine Controls: fMRI Evidence

Brain Topography, 2015

Migraine is a headache disorder characterized by sensitivity to light and sound. Recent research ... more Migraine is a headache disorder characterized by sensitivity to light and sound. Recent research has revealed abnormal visual-spatial attention in migraineurs in between headache attacks. Here, we ask whether these attentional abnormalities can be attributed to specific regions of the known attentional network to help characterize the abnormalities in migraine. Specifically, the ventral frontoparietal network of attention is involved with assessing the behavioural relevance of unattended stimuli. Given the decreased suppression of unattended stimuli reported in migraineurs, we hypothesized that migraineurs would have abnormal processing in the ventral portion of the frontoparietal network of attention. To address this, we used functional magnetic resonance imaging to assess the attentional control networks during visual spatial-orienting tasks in migraineurs (N = 16) as compared to non-migraine controls (N = 16). We employed two visual orienting paradigms with target discrimination tasks: (1) voluntary orienting to central arrow cues, and (2) reflexive orienting to peripheral flash cues. While both groups showed activation in the key areas of attentional processing networks, migraineurs showed less activation than non-migraine controls in a key area of the ventral frontoparietal network of attention, the right temporal parietal junction (rTPJ), during both voluntary and reflexive visual spatial orienting. Given the role of rTPJ is to assess the visual environment for behaviorally relevant sensory stimuli outside the focus of attention and signal other attentional areas to reorient attention to behaviorally salient stimuli, our findings fit with previous research showing that migraineurs lack suppression of unattended events and have heightened orienting to sudden onset stimuli in peripheral locations.

Research paper thumbnail of • Can hippocampus be spared in patients with small cell lung carcinoma (SCLC) during cranial radiation therapy (CRT)?

Although CRT is a standard therapy for prevention and treatment of brain metastases (BM) in patie... more Although CRT is a standard therapy for prevention and treatment of brain metastases (BM) in patients with SCLC, neurocognitive impairment (NI) following therapeutic whole brain radiation treatment (WBRT) or prophylactic cranial irradiation (PCI) is a major problem & can cause impairment in quality of life. A RTOG study is assessing various outcomes by avoiding the hippocampus (AH) during WBRT in different malignancies. The estimated risk of hippocampal avoidance region metastases (HM) in patients with SCLC before & after WBRT/PCI is not known. AH during CRT may delay the onset of NI in such patients. Our study aims to determine risk of HM in patients with SCLC and to assess clinical factors correlate with it. Methods: A patients cohort of SCLC diagnosed and treated at the Saskatoon Cancer Center between 2005 and 2012 were followed. All MRI and/or CT scans were independently reviewed by a neuroradiologist. HM was defined as BM within 5 mm of hippocampus. Binary Logistic regression an...

Research paper thumbnail of Inclusion of Attentional Networks in the Pre-Surgical Neuroimaging Assessment of a Large Deep Hemispheric Cavernous Malformation: An fMRI Case Report

Cerebrovascular Diseases, 2015

Functional magnetic resonance imaging (fMRI) is a noninvasive and reliable tool for mapping eloqu... more Functional magnetic resonance imaging (fMRI) is a noninvasive and reliable tool for mapping eloquent cortex in patients prior to brain surgery. Ensuring intact perceptual and cognitive processing is a key goal for neurosurgeons, and recent research has indicated the value of including attentional network processing in pre-surgical fMRI in order to help preserve such abilities, including reading, after surgery. We report a 42-year-old patient with a large cavernous malformation, near the left basal ganglia. The lesion measured 3.8 × 1.7 × 1.8 cm. In consultation with the patient and the multidisciplinary cerebrovascular team, the decision was made to offer the patient surgical resection. The surgical resection involved planned access via the left superior parietal lobule using stereotactic location. The patient declined an awake craniotomy; therefore, direct electrocortical stimulation (ECS) could not be used for intraoperative language localization in this case. Pre-surgical planning included fMRI localization of language, motor, sensory, and attentional processing. The key finding was that both reading and attention-processing tasks revealed consistent activation of the left superior parietal lobule, part of the attentional control network, and the site of the planned surgical access. Given this information, surgical access was adjusted to avoid interference with the attentional control network. The lesion was removed via the left inferior parietal lobule. The patient had no new neurologic deficits postoperatively but did develop mild neuropathic pain in the left hand. This case report supports recent research that indicates the value of including fMRI maps of attentional tasks along with traditional language-processing tasks in preoperative planning in patients undergoing neurosurgery procedures. © 2015 S. Karger AG, Basel.