Prevalence and Significance of Impaired Microvascular Tissue Reperfusion Despite Macrovascular Angiographic Reperfusion (No-Reflow)

BackgroundThe relevance of impaired microvascular tissue-level reperfusion despite complete upstream macrovascular angiographic reperfusion (no-reflow) in human stroke remains controversial. We investigated the prevalence and clinical-radiological features of this phenomenon, and its associations with outcomes in three international randomized controlled thrombectomy trials with pre-specified follow-up perfusion imaging.MethodsIn a pooled analysis of the EXTEND-IA (ClinicalTrials.gov number NCT01492725), EXTEND-IA TNK (NCT02388061) and EXTEND-IA TNK Part-two (NCT03340493) trials, patients undergoing thrombectomy with final angiographic extended Thrombolysis In Cerebral Ischemia 2c-3 score for anterior circulation large vessel occlusion and 24-hour follow-up CT or MRI perfusion imaging were included. No-reflow was defined as regions of visually demonstrable persistent hypoperfusion on relative Cerebral Blood Volume or Flow maps within the infarct and verified quantitatively by >15% asymmetry compared to a mirror homologue in the absence of carotid stenosis or re-occlusion.ResultsRegions of no-reflow were identified in 33 of 130 patients (25.3%), encompassed a median of 60.2% (Interquartile range 47.8-70.7%) of the infarct volume, and involved both subcortical (n=26/33,78.8%) and cortical (n=10/33,30.3%) regions. Patients with no-reflow had a median 25.2% ([Interquartile range 16.4-32.2%],p<0.00001) relative Cerebral Blood Volume interside reduction and 19.1% (Interquartile range 3.9-28.3%,p=0.00011) relative Cerebral Blood Flow reduction but similar mean-transit-time (median -3.3%, Interquartile range -11.9-24.4%,p=0.24) within the infarcted region. Baseline characteristics were similar between patients with and without no-reflow. The presence of no-reflow was associated with hemorrhagic transformation (aOR=1.79,95%CI2.32-15.57,p=0.0002), greater infarct growth (ß=11.00,95%CI5.22-16.78,p=0.00027), reduced National Institutes of Health Stroke Score improvement at 24-hours (ß=-4.06,95%CI-6.78--1.34,p=0.004) and being dependent or dead at 90-day as assessed on the modified Rankin Scale (aOR=3.72,95%CI1.35-10.20,p=0.011) in multivariable analysis.ConclusionCerebral no-reflow in humans is common, can be detected by its characteristic perfusion imaging profile using readily available sequences in the clinical setting, and is associated with post-treatment complications and being dependent or dead. Further studies evaluating the role of no-reflow in secondary injury after angiographic reperfusion are warranted.Classification of evidenceThis study provides Class II evidence that cerebral no-reflow on CT/MRI perfusion imaging at 24-hours is associated with post-treatment complications and poor 3-month functional outcome.

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Utility of relative cerebral blood volume mapping derived from perfusion magnetic resonance imaging in the routine follow up of brain tumors

Journal of Neurosurgery ◽

10.3171/jns.1997.86.1.0022 ◽

1997 ◽

Vol 86 (1) ◽

pp. 22-27 ◽

Cited By ~ 61

Author(s):

Tali Siegal ◽

Rina Rubinstein ◽

Tzahala Tzuk-Shina ◽

John M. Gomori

Keyword(s):

Magnetic Resonance ◽

Brain Tumors ◽

Mr Imaging ◽

Blood Volume ◽

Clinical Assessment ◽

Cerebral Blood Volume ◽

Content Type ◽

Relative Cerebral Blood Volume ◽

Fine Print

✓ It was recently demonstrated that imaging of brain tumors by relative cerebral blood volume (CBV) maps reconstructed from dynamic magnetic resonance (MR) data provide similar diagnostic information compared to positron emission tomography (PET) or 201Tl single-photon emission computerized tomography (201Tl-SPECT) scans. The authors used relative CBV mapping for routine follow-up evaluation of patients with brain tumors and compared its sensitivity to diagnostic MR imaging, 201Tl-SPECT and clinical assessment. Fifty-nine patients were prospectively followed using 191 concomitant studies of dual section relative CBV maps, MR imaging, 201Tl-SPECT, and neurological evaluations. Studies were repeated every 2 to 3 months (median three evaluations/patient). The relative CBV maps were graded as relative CBV 0 to 4, where Grades 3 and 4 are indicative of proliferating tumors (four = rapid leak). There were 44 high-grade and 15 low-grade tumors followed during treatment. During the follow-up period a change in relative CBV grade was observed in 56% of the patients, revealing an increasing grade in 72% of them. The rapid leak phenomenon was detected in 35% of all studies and in 81% of those with a worsening relative CBV grade. Tumor progression was detected earlier by relative CBV maps as follows: earlier than MR imaging in 32% of the studies (earlier by a median of 4.5 months; p < 0.01); earlier than 201Tl-SPECT in 63% (median 4.5 months; p < 0.01), and earlier than clinical assessment in 55% (median 6 months; p < 0.01). In 82% of studies with positive MR imaging but negative 201Tl-SPECT, the lesions were smaller than 1.5 cm. The relative CBV maps clearly delineated the appearance of rapid leak in these lesions. Routine use of relative CBV maps that can be implemented on any high-field MR unit and added to the regular MR evaluation provides useful functional information in patients with brain tumors. When used as an adjunct follow-up evaluation it proved more sensitive than the other modalities for early prediction of tumor growth. It is very sensitive to small regional changes, unlike functional imaging such as PET or SPECT scans. Based on previous experience with 76 regional CBV studies, the authors conclude that regional CBV mapping correlates with active tumor and it may separate enhancing scar and radiation injury from infiltrative tumor. A new effect named the rapid leak phenomenon was also observed; this phenomenon, as identified on the regional CBV maps, correlates with high malignancy.

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Collateral status contributes to differences between observed and predicted 24-h infarct volumes in DEFUSE 3

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x20918816 ◽

2020 ◽

Vol 40 (10) ◽

pp. 1966-1974 ◽

Cited By ~ 1

Author(s):

Vaishnavi L Rao ◽

Michael Mlynash ◽

Søren Christensen ◽

Amarnath Yennu ◽

Stephanie Kemp ◽

...

Keyword(s):

Blood Volume ◽

Perfusion Imaging ◽

Intensity Ratio ◽

Cerebral Blood Volume ◽

Ct Perfusion ◽

Infarct Volume ◽

Ct Perfusion Imaging

We previously demonstrated that in the DEFUSE 3 trial, the union of the baseline core and the 24-h Tmax > 6 s perfusion lesion predicts the infarct volume at 24 h. Presently, we assessed if collateral robustness measured by the hypoperfusion intensity ratio (HIR) and cerebral blood volume (CBV) index accounts for the variance in these predictions. DEFUSE 3 patients underwent MRI/CT perfusion imaging at baseline and 24 h post-randomization. We compared baseline and follow-up HIR and CBV index across subgroups stratified by differences between predicted and observed 24-h infarct volumes. Of 123 eligible patients, 34 with 24-h infarcts larger than predicted had less favorable collaterals at baseline (HIR 0.43 vs. 0.32, p = 0.006; CBV Index 0.78 vs. 0.85, p = 0.001) and 24 h (HIR 0.56 vs. 0.07, p = 0.004; CBV Index 0.47 vs. 0.73, p = 0.006) compared to 71 patients with more accurate infarct volume prediction. Eighteen patients with 24-h infarcts smaller than predicted had similar baseline collateral scores but more favorable 24-h CBV indices (0.81 vs. 0.73, p = 0.040). Overall, patients with 24-h infarcts larger than predicted had evidence of less favorable baseline collaterals that fail within 24 h, while patients with 24-h infarcts smaller than predicted typically had favorable collaterals that persisted for 24 h.

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