Ischemic core detection threshold of computed tomography perfusion (CTP) in acute stroke.

PURPOSE: This study aimed to determine the accuracy of detecting ischemic core volume using computed tomography perfusion (CTP) in patients with suspected acute ischemic stroke compared to diffusion-weighted magnetic resonance imaging (DW-MRI) as the reference standard. METHODS: This retrospective monocentric study included patients who underwent CTP and DW-MRI for suspected acute ischemic stroke. The ischemic core size was measured at DW-MRI. The detectability threshold volume was defined as the lowest volume detected by each method. Clinical data on revascularization therapy, along with the clinical decision that influenced the choice, were collected. Volumes of the ischemic cores were compared using the Mann-Whitney U test. RESULTS: Of 83 patients who underwent CTP, 52 patients (median age 73 years, IQR 63-80, 36 men) also had DW-MRI and were included, with a total of 70 ischemic cores. Regarding ischemic cores, only 18/70 (26%) were detected by both CTP and DW-MRI, while 52/70 (74%) were detected only by DW-MRI. The median volume of the 52 ischemic cores undetected on CTP (0.6 mL, IQR 0.2-1.3 mL) was significantly lower (p < 0.001) than that of the 18 ischemic cores detected on CTP (14.2 mL, IQR 7.0-18.4 mL). The smallest ischemic core detected on CTP had a volume of 5.0 mL. Among the 20 patients with undetected ischemic core on CTP, only 10% (2/20) received thrombolysis treatment. CONCLUSIONS: CTP maps failed in detecting ischemic cores smaller than 5 mL. DW-MRI remains essential for suspected small ischemic brain lesions to guide a correct treatment decision-making.

Repetitive Transcranial Magnetic Stimulation With H-Coil Coupled With Cycling for Improving Lower Limb Motor Function After Stroke: An Exploratory Study.

BACKGROUND/OBJECTIVES: Repetitive transcranial magnetic stimulation (rTMS) has been recognized as a promising intervention for the treatment of post-stroke motor deficits. Here, we explore safety, feasibility, and potential effectiveness of high-frequency rTMS (HF-rTMS) delivered with the Hesed coil (H-coil) during active cycling on paretic lower extremity (LE) motor function in chronic stroke. MATERIALS AND METHODS: Twelve subjects with a first-ever stroke were recruited in this double-blind, placebo controlled, crossover study. Eleven sessions of HF-rTMS (40 2s-trains of 20 Hz at 90% resting leg motor threshold) were delivered over the LE motor areas using the H-coil during active cycling for three weeks. Each subject underwent both real and sham rTMS treatments separated by a four-week washout period, in a random sequence. Vital signs were recorded before and after each rTMS session. Any discomfort related to stimulation and side effects were recorded. LE function was also evaluated with Fugl-Meyer assessment (FMA-LE), spasticity was assessed with modified-Ashworth scale and measures of gait speed and endurance (10-meter and 6-min walk tests, respectively) were recorded. RESULTS: No participant reported serious adverse effects. During real rTMS, 4 of 12 subjects reported mild side effects including transitory dizziness and muscle twitches on shoulder, so that intensity of stimulation initially set at 90% of RMT was reduced to 80% of RMT on average in these four subjects. Only real treatment was associated with a significant and sustained improvement in FMA-LL (67% responders vs. 9% of the sham). Spasticity significantly ameliorated only after the real rTMS. Real treatment did not offer advantages on walking timed measures when compared with sham. CONCLUSIONS: This exploratory study suggests that bilateral HF-rTMS combined with cycling is safe and potentially effective in ameliorating paretic LE motor function and spasticity, rather than gait speed or endurance, in chronic stroke.

Corticospinal Tract Injury Estimated From Acute Stroke Imaging Predicts Upper Extremity Motor Recovery After Stroke.

Background and Purpose- Injury to the corticospinal tract (CST) has been shown to have a major effect on upper extremity motor recovery after stroke. This study aimed to examine how well CST injury, measured from neuroimaging acquired during the acute stroke workup, predicts upper extremity motor recovery. Methods- Patients with upper extremity weakness after ischemic stroke were assessed using the upper extremity Fugl-Meyer during the acute stroke hospitalization and again at 3-month follow-up. CST injury was quantified and compared, using 4 different methods, from images obtained as part of the stroke standard-of-care workup. Logistic and linear regression were performed using CST injury to predict ΔFugl-Meyer. Injury to primary motor and premotor cortices were included as potential modifiers of the effect of CST injury on recovery. Results- N=48 patients were enrolled 4.2±2.7 days poststroke and completed 3-month follow-up (median 90-day modified Rankin Scale score, 3; interquartile range, 1.5). CST injury distinguished patients who reached their recovery potential (as predicted from initial impairment) from those who did not, with area under the curve values ranging from 0.70 to 0.8. In addition, CST injury explained ≈20% of the variance in the magnitude of upper extremity recovery, even after controlling for the severity of initial impairment. Results were consistent when comparing 4 different methods of measuring CST injury. Extent of injury to primary motor and premotor cortices did not significantly influence the predictive value that CST injury had for recovery. Conclusions- Structural injury to the CST, as estimated from standard-of-care imaging available during the acute stroke hospitalization, is a robust way to distinguish patients who achieve their predicted recovery potential and explains a significant amount of the variance in poststroke upper extremity motor recovery.