CT Perfusion: More Than What You Thought

Abstract

A cute stroke treatment has dramatically changed in the past decade. Boundaries are crossed, and previous axioms are no longer relevant. The results of the DWI or CTP Assessment with Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention with Trevo (DAWN) and Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke 3 (DEFUSE-3) trials, 1,2 examining endovascular thrombectomy (EVT) in the late timeframe (6-24 hours from stroke onset), have thrust perfusion imaging into the evaluation of acute stroke protocol. 3 The primary purpose of CTP is to distinguish salvageable tissue from infarct core and thus improve patient selection for EVT. [3][4][5] It is now widely used as part of an acute stroke CT protocol. However, many stroke centers worldwide routinely perform CTP only for patients beyond the early timeframe. This is in accordance with the recent acute stroke guidelines, recommending CTP in the late (6-24 hour) timeframe. 6 CTP offers other diagnostic utilities. 7 First, CTP may help differentiate ischemic stroke from stroke mimics, including seizure, migraine aura, and conversion disorder. [7][8][9] Although the suspicion for a stroke mimic should not be based solely on CTP, it may add supportive data and help clinicians better diagnose these elusive cases. Second, CTP may contribute valuable information for the selection of candidates for EVT and intravenous thrombolysis (IVT), despite a low NIHSS score. 3 The NIHSS gives much weight to motor function and dominant hemisphere. However, various infarcts may result in neurologic sequelae, not fully revealed by the NIHSS. 10 These patients may greatly benefit from IVT in case a penumbral lesion is identified. Third, CTP can demonstrate the severity of hypoperfusion in the presence of carotid occlusion or dissection and thus help determine the need for reperfusion therapy. 7,11 In this issue of the American Journal of Neuroradiology, Amukotuwa et al 12 examined the use of CTP to aid in interpretation of CTA for distal vessel occlusion (DVO) identification. They demonstrated that the use of time-to-maximum (Tmax) maps significantly improved the diagnostic performance for detecting DVO.Detection of DVO has great importance. The field of endovascular thrombectomy is rapidly emerging, and evidence is growing regarding the beneficial effect of EVT on distal M2 occlusions. 13 Furthermore, EVT targeting very distal occlusions including M3/

CT Brain Perfusion in the Prediction of Final Infarct Volume: A Prospective Study of Different Software Settings for Acute Ischemic Core Calculation

“…It must be noted that the above-mentioned studies reported GIC had important limitations, as they used only NECT follow-up for the evaluation of FIV. That approach was likely error-prone as MRI has been shown to be the most accurate diagnostic method for assessing acute ischemic changes [ 26 , 27 , 28 , 29 ]. Due to consistent MRI follow-up, we consider our volumetric FIV data to be more reliable; moreover, all subjects underwent MRI within the same time interval, scans were performed on the same 1.5T MRI scanner and the FIV was measured by one neuroradiologist.…”

“…For the measurement of FIV, they used a 5–7-day NECT follow-up. It is well known that CT sensitivity for acute ischemic changes is lower than MRI sensitivity [ 26 , 27 , 28 , 29 ]. Moreover, the follow-up was conducted 5–7 days after EVT, which is an important difference from our follow-up, which was conducted one day after EVT.…”

Imaging biomarkers for clinical applications in neuro-oncology: current status and future perspectives

“…Available, rapid, and suitable for critically ill patients needing prompt intervention, imaging biomarkers are good for efficacy and safety outcome evaluation, as fast and reliable imaging biomarker interpretations are critical for making influential therapeutic decisions and prognostications in patients with acute ischemic stroke [ 142 , 143 ]. CT perfusion imaging can provide information about tumor vasculature and in vivo assessment of vascular parameters such as permeability surface area-product (PS) and relative CBV.…”