High-frequency optical coherence tomography for endovascular management of cerebral aneurysms.

Endovascular management of intracranial aneurysms has become the mainstay of treatment in recent years; however, retreatment rates remain as high as 1 in 5. High-frequency optical coherence tomography (HF-OCT) is an emerging imaging modality for the assessment, treatment and follow-up of cerebral aneurysms. EMBASE and SCOPUS databases were searched for studies relating to the management of intracranial aneurysm with OCT. A combination of keywords were used including 'cerebral aneurysm', 'intracranial aneurysm', 'high-frequency optical coherence tomography', 'optical coherence tomography', and 'optical frequency domain imaging'. There were 23 papers included in this review. For the assessment of intracranial aneurysm, OCT was able to accurately assess aneurysm morphology as well as detailed analysis of arterial wall layers. During IA treatment, OCT was used to assess and troubleshoot stent placement to optimise successful isolation from the circulation. In the follow-up period, endothelial growth patterns were visualised by OCT imaging. OCT shows promise for the treatment of IAs at all stages of management. Due to the novel development of HF-OCT, there is limited longitudinal data in human studies. Further research in this area is required with a focus specifically on long-term treatment outcomes in humans.

Occult contrast retention post-thrombectomy on 24-h follow-up dual-energy CT: Associations and impact on imaging analysis.

BACKGROUND: Following reperfusion treatment in ischemic stroke, computed tomography (CT) imaging at 24 h is widely used to assess radiological outcomes. Even without visible hyperattenuation, occult angiographic contrast may persist in the brain and confound Hounsfield unit-based imaging metrics, such as net water uptake (NWU). AIMS: We aimed to assess the presence and factors associated with retained contrast post-thrombectomy on 24-h imaging using dual-energy CT (DECT), and its impact on the accuracy of NWU as a measure of cerebral edema. METHODS: Consecutive patients with anterior circulation large vessel occlusion who had post-thrombectomy DECT performed 24-h post-treatment from two thrombectomy stroke centers were retrospectively studied. NWU was calculated by interside comparison of HUs of the infarct lesion and its mirror homolog. Retained contrast was quantified by the difference in NWU values with and without adjustment for iodine. Patients with visible hyperdensities from hemorrhagic transformation or visible contrast retention and bilateral infarcts were excluded. Cerebral edema was measured by relative hemispheric volume (rHV) and midline shift (MLS). RESULTS: Of 125 patients analyzed (median age 71 (IQR = 61-80), baseline National Institutes of Health Stroke Scale (NIHSS) 16 (IQR = 9.75-21)), reperfusion (defined as extended-Thrombolysis-In-Cerebral-Infarction 2b-3) was achieved in 113 patients (90.4%). Iodine-subtracted NWU was significantly higher than unadjusted NWU (17.1% vs 10.8%, p < 0.001). In multivariable median regression analysis, increased age (p = 0.024), number of passes (p = 0.006), final infarct volume (p = 0.023), and study site (p = 0.021) were independently associated with amount of retained contrast. Iodine-subtracted NWU correlated with rHV (rho = 0.154, p = 0.043) and MLS (rho = 0.165, p = 0.033) but unadjusted NWU did not (rHV rho = -0.035, p = 0.35; MLS rho = 0.035, p = 0.347). CONCLUSIONS: Angiographic iodine contrast is retained in brain parenchyma 24-h post-thrombectomy, even without visually obvious hyperdensities on CT, and significantly affects NWU measurements. Adjustment for retained iodine using DECT is required for accurate NWU measurements post-thrombectomy. Future quantitative studies analyzing CT after thrombectomy should consider occult contrast retention.

Spontaneous Intracranial Hypotension and Spinal Epidural CSF Leaks: Diagnosis and Management.

Spontaneous intracranial hypotension from spinal cerebrospinal fluid leak is a condition that often presents as orthostatic headaches. Diagnosis and localisation of spinal CSF leaks remain difficult despite multiple imaging modalities that can be used to aid identification. These include traditional CT myelography and MRI as well as newer techniques such as dynamic and digital subtraction myelography. Leaks can be classified into types and optimal localisation and management techniques vary by type of leak. Localisation of a leak can aid in targeting treatment such as an epidural blood patch if conservative measures fail. Where unsuccessful, repeated blood patches and novel techniques can be used to improve patient symptoms. Much of this condition is not well understood and evidence is lacking, with many avenues for potential research.

Antiplatelet Drugs for Neurointerventions: Part 2 Clinical Applications.

Endovascular techniques have expanded to include balloon and stent-assistance, flow diversion and individualized endovascular occlusion devices, to widen the treatment spectrum for more complex aneurysm morphologies. While usually well-tolerated by patients, endovascular treatment of intracranial aneurysms carries the risk of complications, with procedure-related ischemic complications being the most common. Several antiplatelet agents have been studied in a neurointerventional setting for both prophylaxis and in the setting of intraprocedural thrombotic complications. Knowledge of these antiplatelet agents, evidence for their use and common dosages is important for the practicing neurointerventionist to ensure the proper application of these agents.Part one of this two-part review focused on basic platelet physiology, pharmacology of common antiplatelet medications and future directions and therapies. Part two focuses on clinical applications and evidence based therapeutic regimens.

Antiplatelet Drugs for Neurointerventions: Part 1 Clinical Pharmacology.

The development of endovascular treatment for intracranial aneurysms has established new techniques such as balloon and stent-assistance, flow diversion and endosaccular occlusion devices. Antiplatelet treatment is an important aspect to reduce risk of thrombus formation on microcatheters and implanted devices when utilizing these methods. It is particularly relevant for flow diverting stents to prevent early and late stent thrombosis. Consideration of platelet physiology and appropriate selection of antiplatelet medication is important as platelet dysfunction drives many of the pathological processes and complications of neurointerventional procedures. Part one of this review focuses on basic platelet physiology, pharmacology of common antiplatelet medications and future directions and therapies. Part two focuses on clinical applications and evidence-based therapeutic regimens.

Side strain: a tear of internal oblique musculature.

OBJECTIVE: Our objective was to describe the normal MRI anatomy of the musculature of the lateral abdominal wall and the findings in athletes with side strain injury. CONCLUSION: MRI can delineate the sheets of musculature that make up the lateral abdominal wall. Side strain injury is caused by tearing of the internal oblique muscle from the undersurface of one of the lower four ribs or costal cartilages. MRI can document the site of a muscle tear, characterize the severity of injury, and monitor healing.