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Manohar Shroff

University of Toronto, Medical Imaging, Faculty Member

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Phone: 4168455957
Address: 555 Univeristy Avenue
Diagnostic Imaging, Hospital for Sick Children, Toronto

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Morten H. Christiansen

Cornell University

School of the Art Institute of Chicago

David Pierre Leibovitz

Carleton University

Hugo Selma Sánchez

Universidad de la República

Sinclair W Bell

Northern Illinois University

T. Florian Jaeger

University of Rochester

Johns Hopkins University

Alba Marina Cobo Viveros

Universidade de Vigo

University of Groningen

Françoise Van Haeperen

UCLouvain (University of Louvain)

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Papers by Manohar Shroff

Predictive Value of MRI in Diagnosing Brain AVM Recurrence after Angiographically Documented Exclusion in Children

American Journal of Neuroradiology, 2019

BACKGROUND AND PURPOSE: MRI is routinely performed following brain AVM after treatment in childre... more BACKGROUND AND PURPOSE: MRI is routinely performed following brain AVM after treatment in children. Our aim was to determine the predictive values of contrast-enhanced MR imaging and TOF-MRA for brain AVM recurrence in children, compared with conventional angiography and the role of 3D rotational angiography-MR imaging fusion in these cases. MATERIALS AND METHODS: We included all pediatric patients with brain AVMs during an 18-year period with angiographically documented obliteration after treatment. Patients underwent 3T MR imaging, including contrast-enhanced MR imaging, TOF-MRA, and conventional angiography, with a subset undergoing 3D rotational angiography. The predictive values of contrast-enhanced MR imaging and TOF-MRA for brain AVM recurrence were determined. CTA sections reconstructed from 3D rotational angiography were coregistered with and fused to 3D-T1WI for analysis.

Infection and inflammation: radiological insights into patterns of pediatric immune-mediated CNS injury

Neuroradiology

The central nervous system (CNS) undergoes constant immune surveillance enabled via regionally sp... more The central nervous system (CNS) undergoes constant immune surveillance enabled via regionally specialized mechanisms. These include selectively permissive barriers and modifications to interlinked innate and adaptive immune systems that detect and remove an inciting trigger. The end-points of brain injury and edema from these triggers are varied but often follow recognizable patterns due to shared underlying immune drivers. Imaging provides insights to understanding these patterns that often arise from unique interplays of infection, inflammation and genetics. We review the current updates in our understanding of these intersections and through examples of cases from our practice, highlight that infection and inflammation follow diverse yet convergent mechanisms that can challenge the CNS in children.

Abusive head trauma: Canadian and global perspectives

Pediatric Radiology

Canada has come a long way since Dr. C. Henry Kempe first described battered-child syndrome in 19... more Canada has come a long way since Dr. C. Henry Kempe first described battered-child syndrome in 1962. The year 1999 was crucial in Canada’s battle against shaken baby syndrome/abusive head trauma (SBS/AHT), when the first national conference on the topic was held in Saskatoon. This was followed by the issuance of a national statement and multidisciplinary guidelines, recently updated in 2020. Incidence of AHT in Canada is similar to that found in population-based studies from Switzerland and New Zealand. The mainstay of prevention of AHT in Canada is education of parents and caregivers with respect to their response to infant crying. Population-based data for global incidence of AHT are lacking, largely because of social and cultural differences contributing to poor understanding of AHT as a medico-legal entity. India faces a distinct challenge in the battle against female feticide and infanticide.

Decreased Brain Volumes and Infants With Congenital Heart Disease Undergoing Venoarterial Extracorporeal Membrane Oxygenation

Pediatric Critical Care Medicine, 2020

Locations, associations and temporal evolution of intracranial arterial infundibular dilatations in children

Journal of NeuroInterventional Surgery, 2019

BackgroundThere are few data in the literature on the characteristics and natural history of intr... more BackgroundThere are few data in the literature on the characteristics and natural history of intracranial arterial infundibular dilatations in children.MethodsAn institutional review board-approved retrospective review was performed of infundibula reported on MR angiography in patients <18 years of age at our tertiary pediatric institute from 1998 to 2016. Clinical data (age, sex, diagnosis, other vascular variants/pathologies) were recorded and images assessed for vessel of origin, infundibulum size and exact location. Ratios of infundibulum:parent artery were assessed at diagnosis and last follow-up. Temporal evolution to aneurysm was evaluated.ResultsWe found 60 intracranial infundibula in 60 children (male:female=27:33; mean age 9.7±5.2 years, range 2–18 years,). Family history of aneurysms was present in 2/60 (3.3%). Syndromic association was found in 14/60 (23.3%), most frequently sickle cell disease (4/14=28.6%). Mean infundibulum size was 2.2±0.5 mm, with mean ratio to pa...

Radiation Dosimetry of 3D Rotational Neuroangiography and 2D-DSA in Children

American Journal of Neuroradiology, 2018

BACKGROUND AND PURPOSE: The benefit-risk assessment concerning radiation use in pediatric neuroan... more BACKGROUND AND PURPOSE: The benefit-risk assessment concerning radiation use in pediatric neuroangiography requires an extensive understanding of the doses delivered. This work evaluated the effective dose of 3D rotational angiography in a cohort of pediatric patients with complex neurovascular lesions and directly compared it with conventional 2D-biplane DSA. MATERIALS AND METHODS: Thirty-three 3D rotational angiography acquisitions were acquired in 24 pediatric patients (mean age, 10.4 years). When clinically indicated, following 2D-biplane DSA, 3D rotational angiography was performed with 1 of 3 technical protocols (2 subtracted, 1 unsubtracted). The protocols consisted of 1 factory and 2 customized techniques, with images subsequently reconstructed into CT volumes for clinical management. Raw projections and quantitative dose metrics were evaluated, and the effective dose was calculated. RESULTS: All 3D rotational angiography acquisitions were of diagnostic quality and assisted in patient management. The mean effective doses were 0.5, 0.12, and 0.06 mSv for the factory-subtracted, customized-subtracted, and customized-unsubtracted protocols, respectively. The mean effective dose for 2D-biplane DSA was 0.9 mSv. A direct intraprocedural comparison between 3D and 2D acquisitions indicated that customized 3D rotational angiography protocols delivered mean relative doses of 9% and 15% in unsubtracted and subtracted acquisitions, respectively, compared with biplane DSA, whereas the factory subtracted protocol delivered 68%. CONCLUSIONS: In pediatric neuroangiography, the effective dose for 3D rotational angiography can be significantly lower than for 2D-biplane DSA and can be an essential adjunct in the evaluation of neurovascular lesions. Additionally, available 3D rotational angiography protocols have significant room to be tailored for effectiveness and dose optimization, depending on the clinical question.

RA-10SUBTLE FINDINGS ON SPINAL MRIs IN CHILDREN NEWLY DIAGNOSED WITH MEDULLOBLASTOMA

Neuro-Oncology, 2016

Pediatric Idiopathic Intervertebral Disc Calcification

Pediatric Neurology, 2016

Objective To review pediatric idiopathic intervertebral disc calcification (PIIVDC) within a sing... more Objective To review pediatric idiopathic intervertebral disc calcification (PIIVDC) within a single center and within the literature to outline the disease course, management, and outcome. Study design A retrospective chart review was performed spanning the period between January 2001 and February 2016 for diagnoses of PIIVDC. Patient age, sex, symptoms, and history and physical and neurologic findings were reviewed. Laboratory and imaging findings, management, follow-up, and outcome also were studied. Results Nine cases of PIIVDC were identified; they included 6 male and 3 female patients, with an age range of 23 months to 12 years. Two patients were asymptomatic, and PIIVDC was discovered incidentally. Of the remaining 7 patients, 5 presented with neck and/or back pain, 1 with painless torticollis, and 1 with painful torticollis. One patient reported neurologic symptoms of pain radiating along 1 dermatome. Disc spaces affected were 5 cervical, 4 thoracic, and 2 lumbar, with 2 patients having more than 1 space affected. All patients were managed conservatively. In 1 case, symptoms and lesions persisted after 5 years, but the remainder had complete symptom resolution, generally within 6 months. Conclusions The etiology of PIIVDC remains unknown but appears to occur spontaneously, without preceding trauma or underlying medical condition. A conservative approach to patients without severe neurologic deficit with outpatient follow-up is supported.

Neuroimaging Clinics of North America. Pediatric demyelinating disease and its mimics. Preface

Neuroimaging clinics of North America, 2013

Posterior Reversible Encephalopathy Syndrome - A Rare Complication of Bee-Stings

The Canadian Journal of Neurological Sciences, 2013

Feasibility of ultrasound‐assisted lumbar punctures performed by pediatric oncologists at the point of care

Pediatric Blood & Cancer, 2021

Ultrasound assistance improves success rates and reduces adverse outcomes of lumbar punctures (LP... more Ultrasound assistance improves success rates and reduces adverse outcomes of lumbar punctures (LPs) among adult patients in the emergency room and the operating room, but has not been evaluated in pediatric patients with cancer. Our objectives were (1) to determine whether pediatric oncologists could perform ultrasound‐assisted LPs following a structured teaching curriculum, and (2) to determine the feasibility of recruiting pediatric cancer patients to a clinical trial of this procedure.

Acute Flaccid Myelitis in a 10-Year-Old Girl

Radiology, 2018

Neuroimaging in Neonatal Hypoxic Ischemic Encephalopathy

The Indian Journal of Pediatrics, 2016

Magnetic resonance (MR) imaging is emerging as one of the most important tools in identifying the... more Magnetic resonance (MR) imaging is emerging as one of the most important tools in identifying the etiology of neonatal encephalopathy as well as in predicting long-term outcomes. This makes it imperative to have a broader understanding of normal myelination of the neonatal brain on MR imaging and to be familiar with the spectrum of imaging features in ischemic and non-ischemic neonatal encephalopathy. Hypoxic ischemic injury (HIE) is one of the most common causes of neonatal encephalopathy and imaging appearances are influenced by factors such as the stage of maturation of the neonatal brain and severity as well as duration of ischemic insult. Other common causes of neonatal encephalopathy include infectious diseases, congenital disorders and inborn errors of metabolism.

Mutation and Microsatellite Burden Predict Response to PD-1 Inhibition in Children with Germline DNA Replication Repair Deficiency

Cancers arising from germline DNA mismatch-repair or polymerase-proofreading deficiencies (MMRD a... more Cancers arising from germline DNA mismatch-repair or polymerase-proofreading deficiencies (MMRD and PPD) in children harbour the highest mutational and microsatellite insertion/deletion (MS-indel) burden in humans and are lethal due to inherent resistance to chemo-irradiation. Although immune checkpoint inhibitors (ICI) have failed to benefit children in previous studies, we hypothesized that hypermutation caused by MMRD and PPD will improve outcomes following ICI in these patients. ICI treatment of 45 progressive/recurrent tumours from 38 patients revealed durable objective responses in the majority, culminating in 3-year survival of 41.4%. High mutation burden predicted response for ultra-hypermutant cancers (>100 mutations/Mb) enriched for combined MMRD+PPD, while MS-indels predicted response in MMRD tumours with lower mutation burden (10-100 mutations/Mb). Further, both mechanisms were associated with increased immune infiltration even in “immunologically-cold” tumours such a...

Long Vascular Sheaths for Transfemoral Neuroendovascular Procedures in Children

Purpose To evaluate the safety and efficacy of long vascular sheaths for transfemoral neuroendova... more Purpose To evaluate the safety and efficacy of long vascular sheaths for transfemoral neuroendovascular procedures in children. Materials and Methods A retrospective evaluation of transfemoral neuroendovascular procedures in children <18 years, using long sheaths was undertaken analyzing procedure type, fluoroscopic times, technical success, access site and systemic complications. Twenty-seven consecutive procedures were included over a 2-year period. Mean age was 8.4 years (standard deviation [SD] 6.3) (range 17.0 months–16.3 years). Results Patients were 44% female and mean weight was 35.0 kg (SD 22.8) (range 9.8–72.2 kg). A third of the procedures were performed in ≤15 kg children. The most common procedure was for embolization (n=13, 48.1%) and the most common indication was dual microcatheter technique (52%). The most common device used was the 5 Fr Cook Shuttle sheath. Mean fluoroscopy time was 61.9 minutes (SD 43.1). Of these procedures, 93% were technically successful. Fe...

Principles and Practice of Radiological Investigations for the Diagnosis of Pediatric Head and Neck Diseases

Pediatric patients present with a wide variety of head and neck pathologies. Although some lesion... more Pediatric patients present with a wide variety of head and neck pathologies. Although some lesions can be diagnosed on clinical grounds, there are many others that require imaging for diagnosis. Imaging plays an important role in distinguishing among the potential diagnoses, as often, history and clinical assessment is limited in these young patients. Beyond diagnosis, imaging has a crucial role in evaluating the location and extent of a lesion for possible intervention. Understanding the imaging appearance of the myriad pathologies which are commonly encountered and their potential complications facilitates optimal management. In this chapter, we review the various imaging modalities available, benefits and limitations of each modality, and discuss the ten subsets of pediatric head and neck pathologies.

Distinct Clinical and Radiographic Phenotypes in Pediatric Patients With Moyamoya

Pediatric Neurology, 2021

BACKGROUND Given the expanding evidence of clinico-radiological differences between moyamoya dise... more BACKGROUND Given the expanding evidence of clinico-radiological differences between moyamoya disease (MMD) and moyamoya syndrome (MMS), we compared the clinical and radiographic features of childhood MMD and MMS to identify predictors of ischemic event recurrence. METHODS We reviewed a pediatric moyamoya cohort followed between 2003 and 2019. Clinical and radiographic characteristics at diagnosis and follow-up were abstracted. Comparisons between MMD and MMS as well as between MMD and two MMS subgroups (neurofibromatosis [MMS-NF1] and sickle cell disease [MMS-SCD]) were performed. RESULTS A total of 111 patients were identified. Patients with MMD presented commonly with transient ischemic attacks (TIAs) (35 % MMD versus 13% MMS-NF1 versus 9.5% MMS-SCD; P = 0.047). Symptomatic stroke presentation (MMD 37% versus MMS-NF1 4% versus 33%; P = 0.0147) and bilateral disease at diagnosis (MMD 73% versus MMS-NF1 22 % versus MMS-SCD 67%; P = 0.0002) were uncommon in MMS-NF1. TIA recurrence was common in MMD (hazard ratio 2.86; P = 0.001). The ivy sign was absent on neuroimaging in a majority of patients with MMS-SCD (MMD 67% versus MMS-NF1 52% versus MMS-SCD 9.5%; P = 0.0002). Predictors of poor motor outcome included early age at diagnosis (odds ratio [OR] 8.45; P = 0.0014), symptomatic stroke presentation (OR 6.6; P = 0.019), and advanced Suzuki stage (OR 3.59; P = 0.019). CONCLUSIONS Moyamoya exhibits different phenotypes based on underlying etiologies. Frequent TIAs is a common phenotype of MMD and symptomatic stroke presentation a common feature of MMD and MMS-SCD, whereas unilateral disease and low infarct burden are common in MMS-NF1. In addition, absence of ivy sign is a common phenotype in MMS-SCD.

Hemorrhagic transformation and stroke recurrence in children with cardiac disease receiving antithrombotic therapy for secondary stroke prevention

Journal of Thrombosis and Haemostasis, 2021

Antithrombotic therapy is currently recommended for stroke prevention in pediatric cardioembolic ... more Antithrombotic therapy is currently recommended for stroke prevention in pediatric cardioembolic stroke where the recurrence risk is high; however, safety concerns remain. The primary objective of this study was to evaluate clinical and radiographic predictors of hemorrhagic transformation and stroke recurrence in children with cardiac disease to ascertain the safety and failure rates for secondary stroke prevention.

Deep venous communication in vein of Galen malformations: incidence, Imaging, and Implications for treatment

Journal of NeuroInterventional Surgery, 2020

BackgroundFailure to appreciate deep venous drainage pathways is a major cause of severe complica... more BackgroundFailure to appreciate deep venous drainage pathways is a major cause of severe complications in the endovascular treatment of vein of Galen aneurysmal malformations (VOGMs).ObjectiveTo report deep venous drainage patterns in patients with VOGM, emphasizing the internal cerebral veins, and to describe the challenges in evaluating these.MethodsPatients with VOGM presenting to our institute between 2000 and 2018 were retrospectively analyzed. Patients with complete and good quality imaging datasets were included in the study. Three neuroradiologists with expertise in the subject independently analyzed the deep venous drainage patterns on multi-sequence MRI and digital subtraction angiography. Follow-up imaging studies were analyzed for alterations in deep venous drainage patterns that occurred following endovascular treatment. Descriptive statistics were used to report findings.ResultsTwenty-three patients had optimal quality MRI imaging and 25 had optimal quality DSA imaging...

The role of MRA in pediatric sickle cell disease with normal transcranial Doppler imaging velocities

Journal of Stroke and Cerebrovascular Diseases, 2020

PURPOSE The purpose of this study was to determine the additional information provided by Magneti... more PURPOSE The purpose of this study was to determine the additional information provided by Magnetic Resonance Angiography (MRA) in pediatric sickle cell disease (SCD) patients with normal Transcranial Doppler imaging (TCDI) examinations. METHODS This cohort study included all pediatric SCD patients over an 18-year period who had no history of stroke and had normal TCDI examinations and subsequently underwent MRA. Routine TCDI inclusive of time-averaged mean of maximum velocities (TAMMV) were assesses and compared with tortuosity on MRA and silent infarct on MRI. RESULTS 86 children (52.3% female; mean age 8.7 ± 3.5years) were included. There were 77 patients (89.5%) with Hb-SS disease and 9(10.4%) with HB-S beta-thalassemia. All patients had normal TAMMV (<170 cm/s) on TCDI. 76/86 (88.3%) patients also had one or more velocity readings <70 cm/s, albeit none in the middle cerebral arteries. Posterior cerebral arteries had the lowest velocities, <70 cm/s in 51.7% (right) and 60.9% (left). Silent MRI infarcts were seen in 27/86 (31.4%) patients. No new lesions were identified on follow-up MRI. Although mild vascular tortuosity was appreciated in 31/86 (36.0%) of the patients, there were no steno-occlusive lesions in the circle of Willis. CONCLUSIONS TCDI and MRA are routinely performed for non-invasively evaluating intracranial vascular abnormalities in children with SCD. In SCD children with no history of TIA or stroke, MRA following a normal TCDI examination is unlikely to show vascular abnormality. However, almost a third of these patients show silent infarcts on MRI, unassociated with MRA changes.

Predictive Value of MRI in Diagnosing Brain AVM Recurrence after Angiographically Documented Exclusion in Children

American Journal of Neuroradiology, 2019

BACKGROUND AND PURPOSE: MRI is routinely performed following brain AVM after treatment in childre... more BACKGROUND AND PURPOSE: MRI is routinely performed following brain AVM after treatment in children. Our aim was to determine the predictive values of contrast-enhanced MR imaging and TOF-MRA for brain AVM recurrence in children, compared with conventional angiography and the role of 3D rotational angiography-MR imaging fusion in these cases. MATERIALS AND METHODS: We included all pediatric patients with brain AVMs during an 18-year period with angiographically documented obliteration after treatment. Patients underwent 3T MR imaging, including contrast-enhanced MR imaging, TOF-MRA, and conventional angiography, with a subset undergoing 3D rotational angiography. The predictive values of contrast-enhanced MR imaging and TOF-MRA for brain AVM recurrence were determined. CTA sections reconstructed from 3D rotational angiography were coregistered with and fused to 3D-T1WI for analysis.

Infection and inflammation: radiological insights into patterns of pediatric immune-mediated CNS injury

Neuroradiology

The central nervous system (CNS) undergoes constant immune surveillance enabled via regionally sp... more The central nervous system (CNS) undergoes constant immune surveillance enabled via regionally specialized mechanisms. These include selectively permissive barriers and modifications to interlinked innate and adaptive immune systems that detect and remove an inciting trigger. The end-points of brain injury and edema from these triggers are varied but often follow recognizable patterns due to shared underlying immune drivers. Imaging provides insights to understanding these patterns that often arise from unique interplays of infection, inflammation and genetics. We review the current updates in our understanding of these intersections and through examples of cases from our practice, highlight that infection and inflammation follow diverse yet convergent mechanisms that can challenge the CNS in children.

Abusive head trauma: Canadian and global perspectives

Pediatric Radiology

Canada has come a long way since Dr. C. Henry Kempe first described battered-child syndrome in 19... more Canada has come a long way since Dr. C. Henry Kempe first described battered-child syndrome in 1962. The year 1999 was crucial in Canada’s battle against shaken baby syndrome/abusive head trauma (SBS/AHT), when the first national conference on the topic was held in Saskatoon. This was followed by the issuance of a national statement and multidisciplinary guidelines, recently updated in 2020. Incidence of AHT in Canada is similar to that found in population-based studies from Switzerland and New Zealand. The mainstay of prevention of AHT in Canada is education of parents and caregivers with respect to their response to infant crying. Population-based data for global incidence of AHT are lacking, largely because of social and cultural differences contributing to poor understanding of AHT as a medico-legal entity. India faces a distinct challenge in the battle against female feticide and infanticide.

Decreased Brain Volumes and Infants With Congenital Heart Disease Undergoing Venoarterial Extracorporeal Membrane Oxygenation

Pediatric Critical Care Medicine, 2020

Locations, associations and temporal evolution of intracranial arterial infundibular dilatations in children

Journal of NeuroInterventional Surgery, 2019

BackgroundThere are few data in the literature on the characteristics and natural history of intr... more BackgroundThere are few data in the literature on the characteristics and natural history of intracranial arterial infundibular dilatations in children.MethodsAn institutional review board-approved retrospective review was performed of infundibula reported on MR angiography in patients <18 years of age at our tertiary pediatric institute from 1998 to 2016. Clinical data (age, sex, diagnosis, other vascular variants/pathologies) were recorded and images assessed for vessel of origin, infundibulum size and exact location. Ratios of infundibulum:parent artery were assessed at diagnosis and last follow-up. Temporal evolution to aneurysm was evaluated.ResultsWe found 60 intracranial infundibula in 60 children (male:female=27:33; mean age 9.7±5.2 years, range 2–18 years,). Family history of aneurysms was present in 2/60 (3.3%). Syndromic association was found in 14/60 (23.3%), most frequently sickle cell disease (4/14=28.6%). Mean infundibulum size was 2.2±0.5 mm, with mean ratio to pa...

Radiation Dosimetry of 3D Rotational Neuroangiography and 2D-DSA in Children

American Journal of Neuroradiology, 2018

BACKGROUND AND PURPOSE: The benefit-risk assessment concerning radiation use in pediatric neuroan... more BACKGROUND AND PURPOSE: The benefit-risk assessment concerning radiation use in pediatric neuroangiography requires an extensive understanding of the doses delivered. This work evaluated the effective dose of 3D rotational angiography in a cohort of pediatric patients with complex neurovascular lesions and directly compared it with conventional 2D-biplane DSA. MATERIALS AND METHODS: Thirty-three 3D rotational angiography acquisitions were acquired in 24 pediatric patients (mean age, 10.4 years). When clinically indicated, following 2D-biplane DSA, 3D rotational angiography was performed with 1 of 3 technical protocols (2 subtracted, 1 unsubtracted). The protocols consisted of 1 factory and 2 customized techniques, with images subsequently reconstructed into CT volumes for clinical management. Raw projections and quantitative dose metrics were evaluated, and the effective dose was calculated. RESULTS: All 3D rotational angiography acquisitions were of diagnostic quality and assisted in patient management. The mean effective doses were 0.5, 0.12, and 0.06 mSv for the factory-subtracted, customized-subtracted, and customized-unsubtracted protocols, respectively. The mean effective dose for 2D-biplane DSA was 0.9 mSv. A direct intraprocedural comparison between 3D and 2D acquisitions indicated that customized 3D rotational angiography protocols delivered mean relative doses of 9% and 15% in unsubtracted and subtracted acquisitions, respectively, compared with biplane DSA, whereas the factory subtracted protocol delivered 68%. CONCLUSIONS: In pediatric neuroangiography, the effective dose for 3D rotational angiography can be significantly lower than for 2D-biplane DSA and can be an essential adjunct in the evaluation of neurovascular lesions. Additionally, available 3D rotational angiography protocols have significant room to be tailored for effectiveness and dose optimization, depending on the clinical question.

RA-10SUBTLE FINDINGS ON SPINAL MRIs IN CHILDREN NEWLY DIAGNOSED WITH MEDULLOBLASTOMA

Neuro-Oncology, 2016

Pediatric Idiopathic Intervertebral Disc Calcification

Pediatric Neurology, 2016

Objective To review pediatric idiopathic intervertebral disc calcification (PIIVDC) within a sing... more Objective To review pediatric idiopathic intervertebral disc calcification (PIIVDC) within a single center and within the literature to outline the disease course, management, and outcome. Study design A retrospective chart review was performed spanning the period between January 2001 and February 2016 for diagnoses of PIIVDC. Patient age, sex, symptoms, and history and physical and neurologic findings were reviewed. Laboratory and imaging findings, management, follow-up, and outcome also were studied. Results Nine cases of PIIVDC were identified; they included 6 male and 3 female patients, with an age range of 23 months to 12 years. Two patients were asymptomatic, and PIIVDC was discovered incidentally. Of the remaining 7 patients, 5 presented with neck and/or back pain, 1 with painless torticollis, and 1 with painful torticollis. One patient reported neurologic symptoms of pain radiating along 1 dermatome. Disc spaces affected were 5 cervical, 4 thoracic, and 2 lumbar, with 2 patients having more than 1 space affected. All patients were managed conservatively. In 1 case, symptoms and lesions persisted after 5 years, but the remainder had complete symptom resolution, generally within 6 months. Conclusions The etiology of PIIVDC remains unknown but appears to occur spontaneously, without preceding trauma or underlying medical condition. A conservative approach to patients without severe neurologic deficit with outpatient follow-up is supported.

Neuroimaging Clinics of North America. Pediatric demyelinating disease and its mimics. Preface

Neuroimaging clinics of North America, 2013

Posterior Reversible Encephalopathy Syndrome - A Rare Complication of Bee-Stings

The Canadian Journal of Neurological Sciences, 2013

Feasibility of ultrasound‐assisted lumbar punctures performed by pediatric oncologists at the point of care

Pediatric Blood & Cancer, 2021

Ultrasound assistance improves success rates and reduces adverse outcomes of lumbar punctures (LP... more Ultrasound assistance improves success rates and reduces adverse outcomes of lumbar punctures (LPs) among adult patients in the emergency room and the operating room, but has not been evaluated in pediatric patients with cancer. Our objectives were (1) to determine whether pediatric oncologists could perform ultrasound‐assisted LPs following a structured teaching curriculum, and (2) to determine the feasibility of recruiting pediatric cancer patients to a clinical trial of this procedure.

Acute Flaccid Myelitis in a 10-Year-Old Girl

Radiology, 2018

Neuroimaging in Neonatal Hypoxic Ischemic Encephalopathy

The Indian Journal of Pediatrics, 2016

Magnetic resonance (MR) imaging is emerging as one of the most important tools in identifying the... more Magnetic resonance (MR) imaging is emerging as one of the most important tools in identifying the etiology of neonatal encephalopathy as well as in predicting long-term outcomes. This makes it imperative to have a broader understanding of normal myelination of the neonatal brain on MR imaging and to be familiar with the spectrum of imaging features in ischemic and non-ischemic neonatal encephalopathy. Hypoxic ischemic injury (HIE) is one of the most common causes of neonatal encephalopathy and imaging appearances are influenced by factors such as the stage of maturation of the neonatal brain and severity as well as duration of ischemic insult. Other common causes of neonatal encephalopathy include infectious diseases, congenital disorders and inborn errors of metabolism.

Mutation and Microsatellite Burden Predict Response to PD-1 Inhibition in Children with Germline DNA Replication Repair Deficiency

Cancers arising from germline DNA mismatch-repair or polymerase-proofreading deficiencies (MMRD a... more Cancers arising from germline DNA mismatch-repair or polymerase-proofreading deficiencies (MMRD and PPD) in children harbour the highest mutational and microsatellite insertion/deletion (MS-indel) burden in humans and are lethal due to inherent resistance to chemo-irradiation. Although immune checkpoint inhibitors (ICI) have failed to benefit children in previous studies, we hypothesized that hypermutation caused by MMRD and PPD will improve outcomes following ICI in these patients. ICI treatment of 45 progressive/recurrent tumours from 38 patients revealed durable objective responses in the majority, culminating in 3-year survival of 41.4%. High mutation burden predicted response for ultra-hypermutant cancers (>100 mutations/Mb) enriched for combined MMRD+PPD, while MS-indels predicted response in MMRD tumours with lower mutation burden (10-100 mutations/Mb). Further, both mechanisms were associated with increased immune infiltration even in “immunologically-cold” tumours such a...

Long Vascular Sheaths for Transfemoral Neuroendovascular Procedures in Children

Purpose To evaluate the safety and efficacy of long vascular sheaths for transfemoral neuroendova... more Purpose To evaluate the safety and efficacy of long vascular sheaths for transfemoral neuroendovascular procedures in children. Materials and Methods A retrospective evaluation of transfemoral neuroendovascular procedures in children <18 years, using long sheaths was undertaken analyzing procedure type, fluoroscopic times, technical success, access site and systemic complications. Twenty-seven consecutive procedures were included over a 2-year period. Mean age was 8.4 years (standard deviation [SD] 6.3) (range 17.0 months–16.3 years). Results Patients were 44% female and mean weight was 35.0 kg (SD 22.8) (range 9.8–72.2 kg). A third of the procedures were performed in ≤15 kg children. The most common procedure was for embolization (n=13, 48.1%) and the most common indication was dual microcatheter technique (52%). The most common device used was the 5 Fr Cook Shuttle sheath. Mean fluoroscopy time was 61.9 minutes (SD 43.1). Of these procedures, 93% were technically successful. Fe...

Principles and Practice of Radiological Investigations for the Diagnosis of Pediatric Head and Neck Diseases

Pediatric patients present with a wide variety of head and neck pathologies. Although some lesion... more Pediatric patients present with a wide variety of head and neck pathologies. Although some lesions can be diagnosed on clinical grounds, there are many others that require imaging for diagnosis. Imaging plays an important role in distinguishing among the potential diagnoses, as often, history and clinical assessment is limited in these young patients. Beyond diagnosis, imaging has a crucial role in evaluating the location and extent of a lesion for possible intervention. Understanding the imaging appearance of the myriad pathologies which are commonly encountered and their potential complications facilitates optimal management. In this chapter, we review the various imaging modalities available, benefits and limitations of each modality, and discuss the ten subsets of pediatric head and neck pathologies.

Distinct Clinical and Radiographic Phenotypes in Pediatric Patients With Moyamoya

Pediatric Neurology, 2021

BACKGROUND Given the expanding evidence of clinico-radiological differences between moyamoya dise... more BACKGROUND Given the expanding evidence of clinico-radiological differences between moyamoya disease (MMD) and moyamoya syndrome (MMS), we compared the clinical and radiographic features of childhood MMD and MMS to identify predictors of ischemic event recurrence. METHODS We reviewed a pediatric moyamoya cohort followed between 2003 and 2019. Clinical and radiographic characteristics at diagnosis and follow-up were abstracted. Comparisons between MMD and MMS as well as between MMD and two MMS subgroups (neurofibromatosis [MMS-NF1] and sickle cell disease [MMS-SCD]) were performed. RESULTS A total of 111 patients were identified. Patients with MMD presented commonly with transient ischemic attacks (TIAs) (35 % MMD versus 13% MMS-NF1 versus 9.5% MMS-SCD; P = 0.047). Symptomatic stroke presentation (MMD 37% versus MMS-NF1 4% versus 33%; P = 0.0147) and bilateral disease at diagnosis (MMD 73% versus MMS-NF1 22 % versus MMS-SCD 67%; P = 0.0002) were uncommon in MMS-NF1. TIA recurrence was common in MMD (hazard ratio 2.86; P = 0.001). The ivy sign was absent on neuroimaging in a majority of patients with MMS-SCD (MMD 67% versus MMS-NF1 52% versus MMS-SCD 9.5%; P = 0.0002). Predictors of poor motor outcome included early age at diagnosis (odds ratio [OR] 8.45; P = 0.0014), symptomatic stroke presentation (OR 6.6; P = 0.019), and advanced Suzuki stage (OR 3.59; P = 0.019). CONCLUSIONS Moyamoya exhibits different phenotypes based on underlying etiologies. Frequent TIAs is a common phenotype of MMD and symptomatic stroke presentation a common feature of MMD and MMS-SCD, whereas unilateral disease and low infarct burden are common in MMS-NF1. In addition, absence of ivy sign is a common phenotype in MMS-SCD.

Hemorrhagic transformation and stroke recurrence in children with cardiac disease receiving antithrombotic therapy for secondary stroke prevention

Journal of Thrombosis and Haemostasis, 2021

Antithrombotic therapy is currently recommended for stroke prevention in pediatric cardioembolic ... more Antithrombotic therapy is currently recommended for stroke prevention in pediatric cardioembolic stroke where the recurrence risk is high; however, safety concerns remain. The primary objective of this study was to evaluate clinical and radiographic predictors of hemorrhagic transformation and stroke recurrence in children with cardiac disease to ascertain the safety and failure rates for secondary stroke prevention.

Deep venous communication in vein of Galen malformations: incidence, Imaging, and Implications for treatment

Journal of NeuroInterventional Surgery, 2020

BackgroundFailure to appreciate deep venous drainage pathways is a major cause of severe complica... more BackgroundFailure to appreciate deep venous drainage pathways is a major cause of severe complications in the endovascular treatment of vein of Galen aneurysmal malformations (VOGMs).ObjectiveTo report deep venous drainage patterns in patients with VOGM, emphasizing the internal cerebral veins, and to describe the challenges in evaluating these.MethodsPatients with VOGM presenting to our institute between 2000 and 2018 were retrospectively analyzed. Patients with complete and good quality imaging datasets were included in the study. Three neuroradiologists with expertise in the subject independently analyzed the deep venous drainage patterns on multi-sequence MRI and digital subtraction angiography. Follow-up imaging studies were analyzed for alterations in deep venous drainage patterns that occurred following endovascular treatment. Descriptive statistics were used to report findings.ResultsTwenty-three patients had optimal quality MRI imaging and 25 had optimal quality DSA imaging...

The role of MRA in pediatric sickle cell disease with normal transcranial Doppler imaging velocities

Journal of Stroke and Cerebrovascular Diseases, 2020

PURPOSE The purpose of this study was to determine the additional information provided by Magneti... more PURPOSE The purpose of this study was to determine the additional information provided by Magnetic Resonance Angiography (MRA) in pediatric sickle cell disease (SCD) patients with normal Transcranial Doppler imaging (TCDI) examinations. METHODS This cohort study included all pediatric SCD patients over an 18-year period who had no history of stroke and had normal TCDI examinations and subsequently underwent MRA. Routine TCDI inclusive of time-averaged mean of maximum velocities (TAMMV) were assesses and compared with tortuosity on MRA and silent infarct on MRI. RESULTS 86 children (52.3% female; mean age 8.7 ± 3.5years) were included. There were 77 patients (89.5%) with Hb-SS disease and 9(10.4%) with HB-S beta-thalassemia. All patients had normal TAMMV (<170 cm/s) on TCDI. 76/86 (88.3%) patients also had one or more velocity readings <70 cm/s, albeit none in the middle cerebral arteries. Posterior cerebral arteries had the lowest velocities, <70 cm/s in 51.7% (right) and 60.9% (left). Silent MRI infarcts were seen in 27/86 (31.4%) patients. No new lesions were identified on follow-up MRI. Although mild vascular tortuosity was appreciated in 31/86 (36.0%) of the patients, there were no steno-occlusive lesions in the circle of Willis. CONCLUSIONS TCDI and MRA are routinely performed for non-invasively evaluating intracranial vascular abnormalities in children with SCD. In SCD children with no history of TIA or stroke, MRA following a normal TCDI examination is unlikely to show vascular abnormality. However, almost a third of these patients show silent infarcts on MRI, unassociated with MRA changes.