Dheeraj Gandhi

Reversible Cerebral Vasoconstriction Syndrome, Part 1: Epidemiology, Pathogenesis, and Clinical Course.

SUMMARY: Reversible cerebral vasoconstriction syndrome is a clinical and radiologic syndrome that represents a common presentation of a diverse group of disorders. The syndrome is characterized by thunderclap headache and reversible vasoconstriction of cerebral arteries, which can either be spontaneous or related to an exogenous trigger. The pathophysiology of reversible cerebral vasoconstriction syndrome is unknown, though alterations in cerebral vascular tone are thought to be a key underlying mechanism. The syndrome typically follows a benign course; however, reversible cerebral vasoconstriction syndrome may result in permanent disability or death in a small minority of patients secondary to complications such as ischemic stroke or intracranial hemorrhage.

Reversible Cerebral Vasoconstriction Syndrome, Part 2: Diagnostic Work-Up, Imaging Evaluation, and Differential Diagnosis

Noninvasive vascular imaging, such as transcranial Doppler sonography and MR angiography, has played an increasingly important role is diagnosing this condition, though conventional angiography remains the reference standard for the evaluation of cerebral artery vasoconstriction. SUMMARY: The diagnostic evaluation of a patient with reversible cerebral vasoconstriction syndrome integrates clinical, laboratory, and radiologic findings. Imaging plays an important role by confirming the presence of cerebral vasoconstriction; monitoring potential complications such as ischemic stroke; and suggesting alternative diagnoses, including CNS vasculitis and aneurysmal subarachnoid hemorrhage. Noninvasive vascular imaging, including transcranial Doppler sonography and MR angiography, has played an increasingly important role in this regard, though conventional angiography remains the criterion standard for the evaluation of cerebral artery vasoconstriction. Newer imaging techniques, including high-resolution vessel wall imaging, may help in the future to better discriminate reversible cerebral vasoconstriction syndrome from primary angiitis of the CNS, an important clinical distinction.

Intracranial Dural Arteriovenous Fistulae: Clinical Presentation and Management Strategies

Dural arteriovenous fistulae (DAVF) are a rare type of acquired intracranial vascular malformation consisting of a pathological shunt located within the dura matter of the brain.1–3 In contradistinction to brain arteriovenous malformations, DAVFs do not harbor a focal nidus.1 These lesions may arise anywhere along the dura, but most commonly are found in the region of the transverse, sigmoid, and cavernous sinuses.2,4–6 DAVF are typically supplied by meningeal arteries and exhibit venous drainage either directly into the dural venous sinuses or via cortical and meningeal veins.2,3 Larger, more complex lesions may recruit pial arterial supply.3 Although a single lesion is present in a majority of patients, multiple shunts can occur in ≤8%.7 DAVF can present with a myriad of clinical signs and symptoms. In general, it is the location and most importantly the venous drainage pattern of DAVF that determines their clinical presentation and potential for serious sequelae.2,8–11 Management strategies for DAVF are consequently guided by these features and include conservative management, as well as endovascular and surgical treatments. This article will begin by reviewing the epidemiology, natural history, and classification of these lesions. Subsequently, clinical presentations, imaging characteristics, and treatment of DAVF will be discussed. DAVF account for only 10% to 15% of intracranial vascular malformations but are slightly over-represented in the posterior fossa (35% of such lesions).4,10 DAVF are typically encountered in middle-aged adults with a median age of onset in the sixth decade.11 Although there is a female predominance, DAVF in men are more likely to display aggressive neurological symptoms and present with hemorrhage.11–13 Rarely, DAVF may be encountered in the pediatric population, where these lesions tend to be more extensive. …

Incidence of Contrast Material–induced Nephropathy after Neuroendovascular Procedures

PURPOSE To report the incidence and risk factors for contrast material ( CM contrast material )-induced nephropathy ( CIN CM-induced nephropathy ) in patients with no history of chronic kidney disease and estimated glomerular filtration rate that exceeded 30 mL/min/1.73 m(2) after a relatively high dose of CM contrast material (≥250 mL) during neuroendovascular procedures. MATERIALS AND METHODS An institutional review board-approved retrospective chart review was performed for all patients who received a dose of CM contrast material 250 mL or greater while they underwent a neuroendovascular procedure between January 2011 and February 2013. The control group consisted of comparable patients who received a CM contrast material dose of 75-249 mL during the same period. Patients with pre-existing estimated glomerular filtration rate of 30 mL/min/1.73 m(2) or less or documented history of chronic kidney disease were excluded. CIN CM-induced nephropathy was defined as an increase in serum creatinine 50% above the baseline or an absolute increase of 0.3 mg/dL at either 24 or 48 hours after the procedure. Statistical analysis was performed with the Student t test, χ(2) analysis, and mixed-model analysis of variance. RESULTS Clinical characteristics between the control and high-dose group were similar for age (95% confidence interval [CI]: -3.69, 5.48; P = .70), sex (95% CI: 0.28, 0.43; P = .62), and ethnicity (95% CI: 0.42, 0.58; P = .47). The average volume of CM contrast material administered was 172 mL in the control group and 326 mL in the high-dose cohort (95% CI: 131.78, 175.05; P < .001). Of the 79 cases in the high-dose cohort, 36 (46%) received a CM contrast material dose between 250 and 299 mL, 29 (37%) received 300-399 mL, nine (11%) received 400-499 mL, and five (6%) received greater than 500 mL. By 48 hours, a statistically significant decrease in serum creatinine was seen in two of the four high-dose CM contrast material dose categories: 250-299 mL (decrease of 24%; [95% CI: 0.04, 0.36]; P = .003) and greater than 500 mL (decrease of 14% [95% CI: -0.33, 0.57]; P = .007). There were four cases (5%) of CIN CM-induced nephropathy : three (4%) at 24 hours and one (1%) at 48 hours. The comorbid rate of diabetes (25% vs 15% [95% CI: -0.01, 0.04]; P < .001) was found to be higher among those who developed CIN CM-induced nephropathy compared with those who did not within the high-dose cohort. No cases of CIN CM-induced nephropathy occurred in the control group. CONCLUSION Risk of developing CIN CM-induced nephropathy is relatively low in patients who undergo neuroendovascular procedures with CM contrast material doses of 250 mL or greater.

Advances in Multiple Sclerosis and its Variants: Conventional and Newer Imaging Techniques

Multiple sclerosis (MS) and its variants are inflammatory as well as neurodegenerative diseases that diffusely affect the central nervous system (CNS). There is a poor correlation between traditional imaging findings and symptoms in patients with MS. Current research in conventional magnetic resonance (MR) imaging of MS and related diseases includes optimization of hardware and pulse sequences and the development of automated and semiautomated techniques to measure and quantify disease burden. Advanced nonconventional MR techniques such as diffusion tensor and functional MR imaging probe the changes found in the CNS, and correlate these findings with clinical measures of disease.

Micro Vascular Plug (MVP)-assisted vessel occlusion in neurovascular pathologies: technical results and initial clinical experience

Background Deconstructive approaches may be necessary to treat a variety of neurovascular pathologies. Recently, a new device has become available for endovascular arterial occlusion that may have unique applications in neurovascular disease. The Micro Vascular Plug (MVP, Reverse Medical, Irvine, California, USA) has been designed for vessel occlusion through targeted embolization. Purpose To report the results from our initial experience with eight consecutive patients in whom the MVP was used to achieve endovascular occlusion of an artery in the head and neck. Methods Eight consecutive patients treated over a nine-month period were included. The patients’ radiographic and electronic medical records were retrospectively reviewed. Specifically demographic information, clinical indication, site of arterial occlusion, size of MVP, time to vessel occlusion, clinical complications, use of other secondary embolic agents, and clinical outcome were recorded. Follow-up information when available is presented. Results The MVP was used in eight patients for the treatment of neurovascular disease. Indications for treatment included post-traumatic head/neck bleeding (n=3), carotid–cavernous fistula (1), vertebral–vertebral fistula (1), giant fusiform vertebral aneurysm (1), stump-emboli after carotid dissection (1), and iatrogenic vertebral artery penetrating injury (1). One device was used in five patients, two in two patients, and one patient with extensive vertebral–vertebral venous fistula required three plugs to effectively trap the fistula from proximal and distal aspects. Vessel occlusion was obtained in <2 min in each case and there were no procedural complications. Four patients were followed up and no incidence of plug migration or vessel recanalization was seen. Conclusions To the best of our knowledge, this is the first series reporting the use of MVP in neurovascular disease. Use of this device may be associated with shorter procedural times and cost savings in comparison with the use of microcoils for vessel occlusion. Our experience shows that MVP can have unique applications in neurovascular pathologies and it complements other occlusive devices.

Interventional neuroradiology applications in otolaryngology, head and neck surgery.

A review of the current clinical applications of a variety of percutaneous and endovascular interventional procedures of the extracranial head and neck is presented. After a description of general principles and embolic agents for interventional procedures, management of specific disorders is presented and procedural steps are described for epistaxis, embolization of vascular head and neck tumors, high-flow and low-flow cervical vascular malformations, head and neck trauma and bleeding, radiofrequency ablation and cryoablation of tumors, along with percutaneous biopsy within the head and neck.

Growth and Rupture Risk of Small Unruptured Intracranial Aneurysms: A Systematic Review

Background Small unruptured intracranial aneurysms (UIAs) are increasingly diagnosed. Management depends on growth and rupture risks, which may vary by aneurysm size. Purpose To summarize evidence about the growth and rupture risk of UIAs 7 mm and smaller and to explore differences in growth and rupture risks of very small (≤3 mm) and small (≤5 mm) aneurysms. Data Sources MEDLINE, EMBASE, Scopus, and the Cochrane Library from inception to 2017 (with no language restrictions). Study Selection Published case series and observational studies that reported natural history data on UIAs 7 mm and smaller. Data Extraction 2 reviewers abstracted study information, evaluated study quality, and graded strength of evidence. Data Synthesis Of 26 studies, 5, 10, and 8 described the growth rate of aneurysms 3 mm and smaller, 5 mm and smaller, and 7 mm and smaller, respectively, whereas rupture rates were reported in 7, 11, and 13 studies for aneurysms 3 mm and smaller, 5 mm and smaller, and 7 mm and smaller, respectively. The annualized growth rate was less than 3% in all but 1 study for all 3 size categories. The annualized rupture rate was 0%, less than 0.5%, and less than 1% for the 3 size categories, respectively. Strength of evidence was very low quality for growth rates and low quality for rupture rates. Limitation Heterogeneous definitions of growth; heterogeneous and selective treatment and follow-up methods, particularly in high-risk patients. Conclusion Poor-quality evidence suggests that small UIAs have low growth and rupture rates and very small UIAs have little or no risk for rupture. Primary Funding Source None.

Use of Pipeline Flex is associated with reduced fluoroscopy time, procedure time, and technical failure compared with the first-generation Pipeline embolization device

Background Flow diversion with the Pipeline embolization device is a well-established method of intracranial aneurysm treatment. However, deployment of the first-generation device (Pipeline Classic) can be technically challenging. The Pipeline Flex contains the same flow-diverting stent with a modified delivery system. Objective To compare procedural outcomes between the first-generation device (Pipeline Classic) and the Pipeline Flex. Methods Thirty-eight of the first 40 consecutive patients who underwent intracranial aneurysm treatment with the Pipeline Flex and 58 of the most recent 60 consecutive patients who underwent treatment with the Pipeline Classic at our institution were evaluated. Patient demographics, aneurysm characteristics, technical procedural details, and early outcomes were analyzed. Results The two groups were comparable for age, gender, and location of target aneurysms. Use of Pipeline Flex decreased procedure time by 44.2 min (p≤0.001) and fluoroscopy time by 22.0 min (p=0.001) compared with the Pipeline Classic. Similarly, radiation exposure was less in the Flex group with a mean difference of 3473.5 Gy cm2 (p=0.002), while contrast usage was decreased with a mean difference of 22.3 mL (p=0.007). These differences remained significant in multivariate regression analysis. Finally, the rate of device deployment failure was lower in the Flex group (7.1%) than in the Classic group (23.9%) (p=0.034). Conclusions Use of Pipeline Flex significantly reduces the total procedure and fluoroscopy time, contrast usage, patient radiation exposure, and proportion of recaptured devices in comparison with the Pipeline Classic, probably owing to an enhanced delivery system that allows for more reliable and controlled deployment.

Pipeline endovascular reconstruction of traumatic dissecting aneurysms of the intracranial internal carotid artery

A 22-year-old woman was involved in a motor vehicle collision resulting in multiple facial fractures and extensive internal carotid artery (ICA) injury including a right carotid-cavernous fistula, complex dissection flap and dissecting aneurysms. Endovascular coil embolization was initially performed to treat the cavernous carotid fistula and then again on two separate occasions to treat expanding dissecting aneurysms. Parent vessel reconstruction of the right ICA was subsequently performed with the Pipeline embolization device, resulting in complete anatomical restoration of this vessel.