IntroductionConventional imaging of stroke was mainly dependent on computed tomography (CT), which included noncontrast imaging that assessed the ASPECTS (Alberta Stroke Program Early CT Score), contrast CT angiography, and CT perfusion. Though these techniques continue to be the mainstay in stroke imaging, there are certain disadvantages such as high radiation dose and need of contrast administration. Further, interpretation of the images can be difficult and, at times, impossible if the patient becomes noncooperative during the contrast study. Considering these issues, there is a need for an alternative imaging technique that gives the same information without contrast administration or radiation. Magnetic resonance imaging (MRI) sequences that include diffusion imaging, noncontrast perfusion arterial spin labeling (ASL) can probably have a distinct advantage. We present the successful use of ASL perfusion imaging in selecting patients for mechanical thrombectomy and the outcome. Keywords► arterial spin labeling ► perfusion imaging ► diffusion perfusion mismatch ► modified Rankin scale score AbstractPresence of ischemic penumbra is the principal factor that decides the need for mechanical thrombectomy in acute stroke patients with large vessel occlusion. Our objective was to evaluate the usefulness of arterial spin labeling (ASL) in detecting diffusion perfusion mismatch and directing patients into mechanical thrombectomy. We retrospectively studied all patients with acute nonhemorrhagic stroke in the anterior circulation, who had undergone stroke imaging with ASL followed by mechanical thrombectomy from July 2016 to November 2016. Area of diffusion perfusion mismatch was graded semiquantitatively into three grades: small, medium, and large. Mismatch was compared with 30-day modified Rankin scale (mRS) score. Interpretable PASL-perfusion images were obtained in all patients. Diffusion perfusion mismatches were present in all patients. Out of six patients with good mRS score, five patients had large diffusion perfusion mismatch. Two out of three patients with poor mRS were secondary to failed recanalization, in spite of large mismatch. One out of nine patients had poor outcome as well as a small area of mismatch. ASL is a rapid noninvasive imaging technique in acute stroke that has got the potential to detect ischemic penumbra.

Intracranial interventions comprise a set of procedures, which are complex and challenging. Further, they are extremely risky because complications in the brain are usually associated with significant mortality and morbidity. Thus, a clear understanding is necessary to handle tortuous vessels because improper planning can result in a higher rate of complications. The combination of long sheaths, specialty wires, and preshaped catheters can enable us to access some of the most complex vascular anatomy. There are several conditions that can contribute to a difficult access. There are few techniques described by different authors. The authors have listed the techniques found useful based on their experience. These challenges include tortuous iliac arteries, dilated tortuous aortic arch, acute takeoff of the arch vessels, tortuous neck vessels with prominent loops, crossing a large aneurysm, extensive peripheral vascular disease, etc.

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Portal hypertension leads to the opening up of collateral pathways to bypass the occlusion or resistance in the portal system. Ectopic varices are formed by such collaterals at many various sites along the gastrointestinal tract other than the usual location, that is, gastroesophageal region. Early diagnosis of ectopic varices needs strong clinical suspicion and contrast-enhanced computed tomography scan as endoscopy may often fail to pinpoint a source. In contrast to gastric varices where the understanding of the disease, as well as endovascular management, is widely studied and documented, the same is not true for ectopic varices due to low incidence. Understanding the applied anatomy and hemodynamic classification is important to decide the most suitable therapy. Interventional radiological procedures are aimed at either decompressing the varices or obliterating them and depend on the patency of the portal system, underlying etiology, and local expertise.