Removal of Antiscatter Grids for Spinal Digital Subtraction Angiography: Dose Reduction without Loss of Diagnostic Value.

Background Spinal digital subtraction angiography (DSA) exposes patients and operators to substantial amounts of radiation. Antiscatter grid (ASG) removal is used to decrease radiation exposure but may reduce image quality. Purpose To determine whether ASG removal during spinal DSA in adults reduces radiation dose while maintaining diagnostic image quality and whether dose reduction is related to body mass index (BMI). Materials and Methods This Health Insurance Portability and Accountability Act-compliant prospective study included adults undergoing spinal DSA between January and December 2016. Each procedure included an additional angiographic acquisition performed twice, once with and once without ASG, either documenting the artery of Adamkiewicz (no pathology group) or the condition leading to the procedure (pathology group). Dose differences between study acquisitions and the influence of BMI were evaluated via paired t test. Two neurointerventionalists blinded to acquisition protocols were asked to independently evaluate a sample of 40 study acquisitions (20 with ASG, 20 without ASG) from 20 randomly selected participants to (a) rate image quality, (b) categorize findings, and (c) determine whether images had been obtained with or without ASG. Percentage agreement on image quality, findings categorization, and ability to correctly identify the acquisition protocol was calculated for both readers. Results Fifty-three participants (mean age ± standard deviation, 51 years ± 15.2; 32 men) were evaluated. ASG removal reduced the mean dose per acquisition by approximately 33% (mean dose-area product and air kerma decreased from 202 to 135.6 µGy/m2 and from 35.3 to 24 mGy, respectively; P < .001) independently of BMI (P = .3). Both readers evaluated all images (40 of 40) as being of diagnostic quality and correctly categorized findings in 19 of 20 (95%) cases. Overall percentage agreement for correct protocol identification was 60% (12 of 20) for grid-in and 45% (nine of 20) for grid-out images. Conclusion Antiscatter grid removal during spinal digital subtraction angiography decreased participants' radiation exposure while preserving diagnostic image quality. © RSNA, 2020.

Thrombectomy Outcomes of Intracranial Atherosclerosis-Related Occlusions.

Background and Purpose- Intracranial atherosclerosis (ICAS) is an important cause of large vessel occlusion and poses unique challenges for emergent endovascular thrombectomy. The risk factor profile and therapeutic outcomes of patients with ICAS-related occlusions (ICAS-O) are unclear. We performed a systematic review and meta-analysis of studies reporting the clinical features and thrombectomy outcomes of large vessel occlusion stroke secondary to underlying ICAS (ICAS-O) versus those of other causes (non-ICAS-O). Methods- A literature search on thrombectomy for ICAS-O was performed. Random-effect meta-analysis was used to analyze the prevalence of stroke risk factors and outcomes of thrombectomy between ICAS-O and non-ICAS-O groups. Results- A total of 1967 patients (496 ICAS-O and 1471 non-ICAS-O) were included. The ICAS-O group had significantly higher prevalence of hypertension (odds ratio [OR] 1.46; 95% CI, 1.10-1.93), diabetes mellitus (OR, 1.68; 95% CI, 1.29-2.20), dyslipidemia (OR, 1.94; 95% CI, 1.04-3.62), smoking history (OR, 2.11; 95% CI, 1.40-3.17) but less atrial fibrillation (OR, 0.20; 95% CI, 0.13-0.31) than the non-ICAS-O group. About thrombectomy outcomes, ICAS-O had higher intraprocedural reocclusion rate (OR, 23.7; 95% CI, 6.96-80.7), need for rescue balloon angioplasty (OR, 9.49; 95% CI, 4.11-21.9), rescue intracranial stenting (OR, 14.9; 95% CI, 7.64-29.2), and longer puncture-to-reperfusion time (80.8 versus 55.5 minutes, mean difference 21.3; 95% CI, 11.3-31.3). There was no statistical difference in the rate of final recanalization (modified Thrombolysis in Cerebral Infarction score of 2b/3; OR, 0.67; 95% CI, 0.36-1.27), symptomatic intracerebral hemorrhage (OR, 0.79; 95% CI, 0.50-1.24), good functional outcome (modified Rankin Scale score of 0-2; OR, 1.16; 95% CI, 0.85-1.58), and mortality (OR, 0.94; 95% CI, 0.64-1.39) between ICAS-O and non-ICAS-O. Conclusions- Patients with ICAS-O display a unique risk factor profile and technical challenges for endovascular reperfusion therapy. Intraprocedural reocclusion occurs in one-third of patients with ICAS-O. Intraarterial glycoprotein IIb/IIIa inhibitors infusion, balloon angioplasty, and intracranial stenting may be viable rescue treatment to achieve revascularization, resulting in comparable outcomes to non-ICAS-O.

The Child With Macrocephaly: Differential Diagnosis and Neuroimaging Findings.

OBJECTIVE: The purpose of this article is to offer a systematic approach to the imaging of children with macrocephaly and to illustrate key neuroimaging features of common and rare but important disorders. CONCLUSION: Macrocephaly is a common clinical finding in children. Increased volume of one of the intracranial compartments can enlarge the head either prenatally or postnatally while the cranial sutures are open. Imaging plays a central role in establishing a diagnosis and guiding management.

Venous hypertensive encephalopathy secondary to venous sinus thrombosis and dural arteriovenous fistula.

A 52-year-old man with a history of factor V Leiden thrombophilia, persistent headaches and papilloedema presented with worsening vision and confusion. MRI and MR angiography of the brain at the time of this presentation showed findings concerning for transverse sinus thrombosis and an associated dural arteriovenous fistula. Dural venous sinus thrombosis can lead to the formation of a dural arteriovenous fistula, which must be considered in the differential diagnosis for intracranial hypertension in patients with thrombophilia.

Safety and efficacy of the surpass streamline for intracranial aneurysms (SESSIA): A multi-center US experience pooled analysis.

BACKGROUND AND PURPOSE: Flow diversion has established as standard treatment for intracranial aneurysms, the Surpass Streamline is the only FDA-approved braided cobalt/chromium alloy implant with 72-96 wires. We aimed to determine the safety and efficacy of the Surpass in a post-marketing large United States cohort. MATERIALS AND METHODS: This is a retrospective multicenter study of consecutive patients treated with the Surpass for intracranial aneurysms between 2018 and 2021. Baseline demographics, comorbidities, and aneurysm characteristics were collected. Efficacy endpoint included aneurysm occlusion on radiographic follow-up. Safety endpoints were major ipsilateral ischemic stroke or treatment-related death. RESULTS: A total of 277 patients with 314 aneurysms were included. Median age was 60 years, 202 (73%) patients were females. Hypertension was the most common comorbidity in 156 (56%) patients. The most common location of the aneurysms was the anterior circulation in 89% (279/314). Mean aneurysm dome width was 5.77 ± 4.75 mm, neck width was 4.22 ± 3.83 mm, and dome/neck ratio was 1.63 ± 1.26. Small-sized aneurysms were 185 (59%). Single device was used in 94% of the patients, mean number of devices per patient was 1.06. At final follow-up, complete obliteration rate was 81% (194/239). Major stroke and death were encountered in 7 (3%) and 6 (2%) cases, respectively. CONCLUSION: This is the largest cohort study using a 72-96 wire flow diverter. The Surpass Streamline demonstrated a favorable safety and efficacy profile, making it a valuable option for treating not only large but also wide-necked small and medium-sized intracranial aneurysms.

The XVS System During Open Spinal Fixation Procedures in Patients Requiring Pedicle Screw Placement in the Lumbosacral Spine.

OBJECTIVE: This pilot study was undertaken to evaluate the safety, performance, and usability of the Xvision-Spine (XVS) System (Augmedics, Arlington Heights, IL) during open spinal fixation procedures in patients requiring pedicle screw placement in the lumbosacral spine. METHODS: The XVS System is an augmented reality head-mounted display (HMD) based on a computer navigation system designed to assist surgeons in accurately placing pedicle screws. It uses an HMD-mounted tracking camera to provide optical tracking technology, and provides the surgeon a translucent direct near-eye display of the navigated surgical instrument's location relative to the computed tomographic image. We report the preliminary results of a prospective series of all consecutive patients who underwent augmented reality-assisted pedicle screw placement in the lumbosacral vertebrae at 3 institutions. Clinical accuracy for each pedicle screw was graded with Gertzbein-Robbins scores by 2 independent and blinded neuroradiologists. RESULTS: The 19 study participants included 8 men and 11 women with a mean age of 59.13 ± 12.09 and 59.91 ± 12.89 years, respectively. Seventeen procedures were successfully completed via the XVS System. Two procedures were not completed due to technical issues with the system's intraoperative scanner. A total of 86 screws were inserted. The accuracy of the XVS System was 97.7%. CONCLUSIONS: The XVS System's performance in accurate placement of pedicle screws in the lumbosacral vertebrae had an overall accuracy of 97.7%. These preliminary results were comparable to the accuracy of other manual computer-assisted navigation systems reported in the literature.

Radial vs. Femoral Artery Access for Procedural Success in Diagnostic Cerebral Angiography : A Randomized Clinical Trial.

BACKGROUND AND PURPOSE: Radial artery access has become the standard of care in percutaneous coronary procedures due to demonstrated patient safety and comfort benefits; however, uptake of radial access for diagnostic cerebral angiography has been limited by practitioner concerns over the ability to achieve procedural success. We aimed to provide randomized clinical trial evidence for the non-inferiority of radial access to achieve procedural success. MATERIAL AND METHODS: Monocentric open label randomized controlled trial with a non-inferiority design and blinded primary outcome assessment. Adult patients referred in-hours for diagnostic cerebral angiography were eligible. Participants underwent permuted block randomization to radial or femoral artery access with an intention-to-treat analysis. The primary outcome was procedural success, defined as selective cannulation and/or diagnostic angiography of predetermined supra-aortic vessels of interest. The non-inferiority limit was 10.0%. Secondary outcomes included postprocedural complications, fluoroscopy and procedural times, radiation dose, contrast volume and rates of vertebral artery cannulation. RESULTS: A total of 80 participants were enrolled (female 42, male 38, mean age 47.0 years, radial access group n = 43, femoral n = 37). One patient in the radial group was excluded after enrollment due to insufficient sonographic radial artery internal diameter. Procedural success was achieved in 41 of 42 participants in the radial group (97.6%) and 36 of 37 in the femoral group (97.3%). The difference between groups was -0.3% (one-sided 95% confidence interval, CI 6.7%) and the null hypothesis was rejected. CONCLUSION: Radial artery access is non-inferior to femoral artery access for procedural success in cerebral angiography. A large multicenter trial is recommended as the next step.

Acute Myelopathy: Vascular and Infectious Diseases.

Vascular and infectious causes are rare but important causes of spinal cord injury. High suspicion for these processes is necessary, as symptoms may progress over hours to days, resulting in delayed presentation and diagnosis and worse outcomes. History and clinical examination findings can assist with localization of the affected vascular territory and spinal level, which will assist with focusing spinal imaging. Open and/or endovascular surgical management depends on the associated vascular abnormality. Infectious myelopathy treatment consists of targeted antimicrobial therapy when possible, infectious source control, and again, close monitoring for systemic complications.

International teleproctoring in neurointerventional surgery and its potential impact on clinical trials in the era of COVID-19: legal and technical considerations.

BACKGROUND: Existing travel restrictions limit the mobility of proctors, significantly delaying clinical trials and the introduction of new neurointerventional devices. We aim to describe in detail technical and legal considerations regarding international teleproctoring, a tool that could waive the need for in-person supervision during procedures. METHODS: International teleproctoring was chosen to provide remote supervision during the first three intracranial aneurysm treatments with a new flow diverter (currently subject of a clinical trial) in the US. Real-time, high-resolution transmission software streamed audiovisual data to a proctor located in Canada. The software allowed the transmission of images in a de-identified, HIPAA-compliant manner. RESULTS: All three flow diverters were implanted as desired by operator and proctor and without complication. The proctor could swap between images from multiple sources and reported complete spatial and situational awareness, without any significant lag or delay in communication. Procedural times and radiologic dose were similar to those of uncomplicated, routine flow diversion cases at our institution. CONCLUSIONS: International teleproctoring was successfully implemented in our clinical practice. Its first use provided important insights for establishing this tool in our field. With no clear horizon for lifting the current travel restrictions, teleproctoring has the potential to remove the need for proctor presence in the angiography suite, thereby allowing the field to advance through the continuation of trials and the introduction of new devices in clinical practice. In order for this tool to be used safely and effectively, highly reliable connection and high-resolution equipment is necessary, and multiple legal nuances have to be considered.

Procedural success with radial access for carotid artery stenting: systematic review and meta-analysis.

BACKGROUND: Femoral access is the traditional approach for endovascular carotid artery stenting. Radial access is increasingly used as an alternative approach due to its known anatomical advantages in patients with unfavorable aortic arch morphology via the femoral approach and its excellent access site safety profile. Our objective was to analyze procedural success using radial access for carotid artery stenting as reported in the literature. METHODS: Three online databases were systematically searched following PRISMA guidelines for studies (n ≥20) using radial artery access for carotid artery stenting (1999-2018). Random-effects meta-analysis was used to pool the procedural success (successful stent placement with no requirement for crossover to femoral access), mortality, and complication rates associated with radial access. RESULTS: Seven eligible studies reported procedural success outcomes with a pooled meta-analysis rate of 90.8% (657/723; 95% CI 86.7% to 94.2%; I2=53.1%). Asymptomatic radial artery occlusion occurred in 5.9% (95% CI 4.1% to 8.0%; I2=0%) and forearm hematoma in 1.4% (95% CI 0.4% to 2.9%; I2=0%). Risk of minor stroke/transient ischemic attack was 1.9% (95% CI 0.6% to 3.8%; I2=42.3%) and major stroke was 1.0% (95% CI 0.4% to 1.8%; I2=0%). There were three deaths across the seven studies (0.6%; 95% CI 0.2% to 1.3%; I2=0%). The meta-analysis was limited by statistically significant heterogeneity for the primary outcome of procedural success. CONCLUSION: Radial access for carotid artery stenting has a high procedural success rate with low rates of mortality, access site complications, and cerebrovascular complications. The potential benefits of this approach in patients with unfavorable aortic arch access should be explored in a prospective randomized trial.

Overview of endovascular thrombectomy accessibility gap for acute ischemic stroke in Asia: A multi-national survey.

Endovascular thrombectomy revolutionized the treatment of acute ischemic stroke. Nevertheless, access to endovascular thrombectomy is limited in many parts of the world. Asia holds 60% of the world's population and its countries carry some of the highest stroke disease burden. To understand the availability of endovascular thrombectomy and intravenous thrombolysis in this region, we interviewed stroke neurologists and neuro-interventionists of 19 Asian countries, and found a large disparity in access to endovascular thrombectomy and intravenous thrombolysis between high- and low-income countries. Lack of neuro-interventionists, comprehensive stroke units, stroke triage systems and high treatment cost are the major obstacles to wider accessibility of endovascular thrombectomy, especially among developing countries. The potential solutions to provide equitable access to stroke revascularization therapy are discussed.

Comparison of intra-aneurysmal flow modification using optical flow imaging to evaluate the performance of Evolve and Pipeline flow diverting stents.

BACKGROUND: Flow diverting stent (FDS) devices have revolutionized the treatment of large and complex brain aneurysms, but there is still room for improvement, particularly on the flow diversion properties and technical challenges associated with stent deployment. In this study we compared flow diversion properties between the new generation Surpass Evolve (Stryker) and the Pipeline Flex (Medtronic) devices by quantitatively evaluating intra-aneurysmal flow modification. METHODS: An in vitro experimental set-up was used, consisting of four patient-specific silicone models with internal carotid aneurysms and a circulating hemodynamic simulation system with pulsatile flow. The Evolve and Pipeline stents were deployed across the neck of each aneurysm model, in a randomized fashion, for a total of eight device deployments. A 60 frames/s digital subtraction angiography run was acquired before and after placement of each FDS. An optical flow-analysis method was used to measure intra-aneurysmal flow modification induced by the stent by calculating a mean aneurysm flow amplitude (MAFA) before and after stent placement and computing a ratio. RESULTS: Average MAFA ratio values calculated from pre- and post-stent placement were significantly lower after deployment of the Evolve (n=4, mean=0.62±0.09) compared with the Pipeline device (n=4, mean=0.71±0.06) (p=0.03). CONCLUSIONS: Our in vitro results show that the Evolve stent had a superior flow diversion effect compared with the Pipeline stent, which-based on clinical evidence-suggest it may promote faster aneurysm occlusion rates in patients.

First clinical experience with the new Surpass Evolve flow diverter: technical and clinical considerations.

OBJECTIVE: To describe the results in patients treated with the Surpass Evolve (SE) device, the new generation of Surpass flow diverters. METHODS: Twenty-five consecutive patients (20 women, average age 58 years), with anterior or posterior circulation aneurysms treated with SEs in two early-user centers, were included. Device properties and related technical properties, imaging and clinical follow-up data, and intraprocedural, early (<30 days) and delayed (>30 days) neurological complications, further divided into minor (silent/non-permanent) and major (permanent) complications, were recorded and analyzed. RESULTS: Twenty-nine SEs were successfully implanted in all subjects to treat 26 aneurysms using an 0.027" microcatheter with an average of 1.2 stents per patient. No intraprocedural thromboembolic or hemorrhagic complications were seen. At clinical follow-up, 24/25 (96%) patients had a modified Rankin Score of 0-2. Mortality was 0%. Imaging follow-up, available in 22/25 (88%) patients (median follow-up time 4 months), showed a complete aneurysm occlusion in 13/23 (57%) imaged lesions. Minor, transitory neurological deficits were recorded in 5/25 (20%) patients. One (4%) major complication was seen in one patient (4%) with a left-sided hemispheric stroke on postprocedural day 4 due to an acute stent thrombosis. CONCLUSIONS: Preliminary experience in patients demonstrates a good performance of the SE. This newly designed implant maintains the engineering characteristics of Surpass flow diverters, including precise placement due to its lower foreshortening and a high mesh density, yet can be deployed through a significantly lower-profile delivery system.

A cadaveric precision and accuracy analysis of augmented reality-mediated percutaneous pedicle implant insertion.

OBJECTIVE: Augmented reality-mediated spine surgery (ARMSS) is a minimally invasive novel technology that has the potential to increase the efficiency, accuracy, and safety of conventional percutaneous pedicle screw insertion methods. Visual 3D spinal anatomical and 2D navigation images are directly projected onto the operator's retina and superimposed over the surgical field, eliminating field of vision and attention shift to a remote display. The objective of this cadaveric study was to assess the accuracy and precision of percutaneous ARMSS pedicle implant insertion. METHODS: Instrumentation was placed in 5 cadaveric torsos via ARMSS with the xvision augmented reality head-mounted display (AR-HMD) platform at levels ranging from T5 to S1 for a total of 113 total implants (93 pedicle screws and 20 Jamshidi needles). Postprocedural CT scans were graded by two independent neuroradiologists using the Gertzbein-Robbins scale (grades A-E) for clinical accuracy. Technical precision was calculated using superimposition analysis employing the Medical Image Interaction Toolkit to yield angular trajectory (°) and linear screw tip (mm) deviation from the virtual pedicle screw position compared with the actual pedicle screw position on postprocedural CT imaging. RESULTS: The overall implant insertion clinical accuracy achieved was 99.1%. Lumbosacral and thoracic clinical accuracies were 100% and 98.2%, respectively. Specifically, among all implants inserted, 112 were noted to be Gertzbein-Robbins grade A or B (99.12%), with only 1 medial Gertzbein-Robbins grade C breach (> 2-mm pedicle breach) in a thoracic pedicle at T9. Precision analysis of the inserted pedicle screws yielded a mean screw tip linear deviation of 1.98 mm (99% CI 1.74-2.22 mm) and a mean angular error of 1.29° (99% CI 1.11°-1.46°) from the projected trajectory. These data compare favorably with data from existing navigation platforms and regulatory precision requirements mandating that linear and angular deviation be less than 3 mm (p < 0.01) and 3° (p < 0.01), respectively. CONCLUSIONS: Percutaneous ARMSS pedicle implant insertion is a technically feasible, accurate, and highly precise method.

Transradial approach in the treatment of a sacral dural arteriovenous fistula: a technical note.

Sacral dural arteriovenous fistulas (SDAVFs) are rare, constituting no more than 10% of all spinal dural fistulas. They are most commonly fed by the lateral sacral artery (LSA), a branch of the internal iliac artery (IIA). Catheterization of this vessel requires either a crossover at the aortic bifurcation in cases of right femoral access or retrograde catheterization from the ipsilateral common femoral artery. We present the case of a 79-year-old man with tethered cord syndrome and a symptomatic SDAVF fed by two feeders from the left LSA. Spinal diagnostic angiography was made exceptionally challenging by an aorto-bi-iliac endograft, and selective catheterization of the left IIA was not possible. The patient could not undergo surgery due to multiple comorbidities, therefore embolization was considered the best approach. The procedure was carried out through a transradial access (TRA) with Onyx and n-butyl cyanoacrylate. The SDAVF was successfully treated and the patient made a full neurological recovery.

Republished: Transradial approach in the treatment of a sacral dural arteriovenous fistula: a technical note.

Sacral dural arteriovenous fistulas (SDAVFs) are rare, constituting no more than 10% of all spinal dural fistulas. They are most commonly fed by the lateral sacral artery (LSA), a branch of the internal iliac artery (IIA). Catheterization of this vessel requires either a crossover at the aortic bifurcation in cases of right femoral access or retrograde catheterization from the ipsilateral common femoral artery. We present the case of a 79-year-old man with tethered cord syndrome and a symptomatic SDAVF fed by two feeders from the left LSA. Spinal diagnostic angiography was made exceptionally challenging by an aorto-bi-iliac endograft, and selective catheterization of the left IIA was not possible. The patient could not undergo surgery due to multiple comorbidities, therefore embolization was considered the best approach. The procedure was carried out through a transradial access (TRA) with Onyx and n-butyl cyanoacrylate. The SDAVF was successfully treated and the patient made a full neurological recovery.

Endovascular Thrombectomy for Distal Occlusion Using a Semi-Deployed Stentriever: Report of 2 Cases and Technical Note.

Distal intracranial occlusions can sometimes cause significant neurological deficits. Endovascular thrombectomy in these vessels may improve outcome but carry a higher risk of haemorrhagic complications due to the small calibre and tortuosity of the target vessel. We report two cases of isolated M2/3 artery occlusion causing dense hemiplegia that was successfully treated with stent retrieval thrombectomy. A "semi-deployment technique" of a 3 mm stentriever was employed at the M2/3 bifurcation of the middle cerebral artery. Partial stent unsheathing allowed adequate clot engagement while avoiding excessive tension by the stent metal struts along the tortuous course of a distal vessel. Complete revascularization was achieved after firstpass of the stent retriever without complication, resulting in good clinical outcome in both cases. The described semi-deployment technique reduces the radial and tractional force exerted by the stentreiver on small branches, and may reduce the risk of vessel laceration or dissection in distal vessel thrombectomy.

Periprocedural complications of second-generation flow diverter treatment using Pipeline Flex for unruptured intracranial aneurysms: a systematic review and meta-analysis.

BACKGROUND: Flow diverters are a breakthrough treatment for large and giant intracranial aneurysms but carry a risk of periprocedural death or major stroke. Pipeline Flex is a second-generation device that is thought to have lower complication rates because of improvements in the delivery system as well as increased operator experience. Our objective was to analyze the risk of periprocedural death or major complications using Pipeline Flex for unruptured intracranial aneurysms. METHODS: A systematic search of three databases was performed for studies of ≥10 treatments using Pipeline Flex for unruptured intracranial aneurysms (2014-2019) using PRISMA guidelines. Random effects meta-analysis was used to pool the rates of periprocedural (<30 days) death, major ischemic stroke, symptomatic intracranial hemorrhage, and minor stroke/transient ischemic attack. RESULTS: We included eight studies reporting 901 treatments in 879 patients. Periprocedural mortality (<30 days) was 0.8% (5/901; 95% CI 0.4% to 1.5%; I2=0%). Rate of major complications (death, major ischemic stroke, or symptomatic intracranial hemorrhage) was 1.8% (14/901; 95% CI 1.0% to 2.7%; I2=0%). Aneurysm size ≥10 mm was a statistically significant predictor of a major complication (OR 6.4; 95% CI 2.0 to 20.7; p=0.002). Risk of a major complication in aneurysms <10 mm was 0.9% (95% CI 0.3% to 1.7%; I2=0%). The meta-analysis was limited by the predominance of anterior circulation aneurysms. CONCLUSION: Treatment of unruptured intracranial aneurysms using the Pipeline Flex flow diverter has a low periprocedural risk of death (0.8%) or major complication (1.8%). The risk of a major complication is significantly higher for large/giant aneurysms (4.4%) and is very low for aneurysms <10 mm (0.9%).

The Role of Diffusion Tensor Imaging in Detecting Hippocampal Injury Following Neonatal Hypoxic-Ischemic Encephalopathy.

BACKGROUND AND PURPOSE: Neonatal hypoxic-ischemic injury of the brain and resultant encephalopathy (HIE) leads to major developmental impairments by school age. Conventional/anatomical MRI often fails to detect hippocampal injury in mild cases. We hypothesize that diffusion tensor imaging (DTI) has greater sensitivity for identifying subtle hippocampal injury. METHODS: We retrospectively analyzed DTI data collected from a cohort of neonates with HIE and controls. Conventional MRI sequences were classified qualitatively according to severity using a modified Barkovich scale. Using multivariate linear regression, we compared hippocampal DTI scalars of HIE patients and controls. Spearman correlation was used to test the association of DTI scalars in the hippocampal and thalamic regions. A multiple regression analysis tested the association of the DTI scalars with short-term outcomes. RESULTS: Fifty-five neonates with HIE (42% males) and 13 controls (54% males) were included. Hippocampal DTI scalars were similar between HIE and control groups, even when restricting the HIE group to those with moderate-to-severe injury (8 subjects). DTI scalars of the thalamus were significantly lower in the moderate-to-severely affected patients compared to controls (right fractional anisotropy [FA] .148 vs. .182, P = .01; left FA .147 vs. .181, P = .03). Hippocampal and thalamic DTI scalars were correlated (P < .001). Hippocampal DTI scalars were not associated with short-term outcomes. CONCLUSIONS: Quantitative DTI analysis of the hippocampus in neonates following HIE is a feasible technique to examine neuronal injury. Although DTI scalars were useful in identifying thalamic injury in our cohort, hippocampal DTI analysis did not provide additional information regarding hippocampal injury following HIE.