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ObjectivesWe tested whether FLAIR vascular hyperintensities (FVH)–DWI mismatch could identify candidates for thrombectomy most likely to benefit from revascularization.MethodsWe retrospectively reviewed 100 patients with proximal MCA occlusion from 18 stroke centers randomized in the IV-thrombolysis plus mechanical thrombectomy arm of the THRACE trial (2010–2015). We tested the associations between successful revascularization on digital subtraction angiography (modified Thrombolysis in Cerebral Infarction 2b/3) and 3-month favorable outcome (modified Rankin Scale score ≤ 2), stratified on FVH–DWI mismatch status, with secondary analyses adjusted on National Institutes of Health Stroke Scale (NIHSS) and DWI lesion volume.ResultsFVH–DWI mismatch was present in 79% of patients, with a similar prevalence at 1.5 T (80%) and 3 T (78%). Successful revascularization (74%) was more frequent in patients with FVH–DWI mismatch (63/79, 80%) than in patients without (11/21, 52%), p = 0.01. The OR of favorable outcome for revascularization were 15.05 (95% CI 3.12–72.61, p < 0.001) in patients with FVH–DWI mismatch and 0.83 (95% CI 0.15–4.64, p = 0.84) in patients without FVH–DWI mismatch (p = 0.011 for interaction). Similar results were observed after adjustment for NIHSS (OR = 12.73 [95% CI 2.69–60.41, p = 0.001] and 0.96 [95% CI 0.15–6.30, p = 0.96]) or for DWI volume (OR = 12.37 [95% CI 2.76–55.44, p = 0.001] and 0.91 [95% CI 0.16–5.33, p = 0.92]) in patients with and without FVH–DWI mismatch, respectively.ConclusionsThe FVH–DWI mismatch identifies patients likeliest to benefit from revascularization, irrespective of initial DWI lesion volume and clinical stroke severity, and could serve as a useful surrogate marker for penumbral evaluation.Key Points• The FVH–DWI mismatch, defined by FLAIR vascular hyperintensities (FVH) located beyond the boundaries of the DWI lesion, is associated with large penumbra.• Among stroke patients with proximal middle cerebral artery occlusion referred for thrombectomy, those with FVH–DWI mismatch are most likely to benefit from revascularization.• FVH–DWI mismatch provides an alternative to PWI–DWI mismatch in order to select patients who are candidates for thrombectomy.

PurposeTo investigate the feasibility and clinical utility of a compressed-sensing-accelerated subtractionless whole-body MRA (CS-WBMRA) protocol with only contrast injection for suspected arterial diseases, by comparison to conventional dual-pass subtraction-based whole-body MRA (conventional-WBMRA) and available computed tomography angiography (CTA).Materials and methodsThis prospective study assessed 86 patients (mean age, 56 years ± 16.4 [standard deviation]; 25 women) with suspected arterial diseases from May 2021 to December 2022, who underwent CS-WBMRA (n = 48, mean age, 55.9 years ± 16.4 [standard deviation]; 25 women) and conventional-WBMRA (n = 38, mean age, 48 years ± 17.4 [standard deviation]; 20 women) on a 3.0 T MRI after random group assignment based on the chronological order of enrolment. Of all enrolled patients administered the CS-WBMRA protocol, 35% (17/48) underwent CTA as required by clinical demands. Two experienced radiologists independently scored the qualitative image quality and venous enhancement contamination. Quantitative image assessment was carried out by determining and comparing the apparent signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) of four representative arterial segments. The total examination time and contrast-dose were also recorded. The independent samples t-test or the Wilcoxon rank sum test was used for statistical analysis.ResultsThe overall scores of CS-WBMRA outperformed those of conventional-WMBRA (3.40 ± 0.60 vs 3.22 ± 0.55, P < 0.001). In total, 1776 and 1406 arterial segments in the CS-WBMRA and conventional-WBMRA group were evaluated. Qualitative image scores for 7 (of 15) vessel segments in the CS-WMBRA group had statistically significantly increased values compared to those of the conventional-WBMRA groups (P < 0.05). Scores from the other 8 segments showed similar image quality (P > 0.05) between the two protocols. In the quantitative analysis, overall apparent SNRs were significantly higher in the conventional-WBMRA group than in the CS-WBMRA group (214.98 ± 136.05 vs 164.90 ± 118.05; P < 0.001), while overall apparent CNRs were not significantly different in these two groups (CS vs conventional: 107.13 ± 72.323 vs 161.24 ± 118.64; P > 0.05). In the CS-WBMRA group, 7 of 1776 (0.4%) vessel segments were contaminated severely by venous enhancement, while in the convention-WBMRA group, 317 of 1406 (23%) were rated as severe contamination. In the CS-WBMRA group, total examination and reconstruction times were only 7 min and 10 min, respectively, vs 20 min and < 30 s for the conventional WBMRA group, respectively. The contrast agent dose used in the CS-WBMRA protocol was reduced by half compared to conventional-WBMRA protocol (18.7 ± 3.5 ml vs 37.2 ± 5.4 ml, P = 0.008).ConclusionThe CS-WBMRA protocol provides excellent image quality and sufficient diagnostic accuracy for whole-body arterial disease, with relatively faster workflow and half-dose reduction of contrast agent, which has greater potential in clinical practice compared with conventional-WBMRA.

Early and late microvascular obstruction (MVO) assessed by cardiovascular magnetic resonance (CMR) are prognostic markers for short-term clinical endpoints after acute ST-elevation myocardial infarction (STEMI). However, there is a lack of studies with long-term follow-up periods (>24 months). STEMI patients reperfused by primary angioplasty (n = 129) underwent MRI at a median of 2 days after the index event. Early MVO was determined on dynamic Gd first-pass images directly after the administration of 0.1 mmol/kg bodyweight Gd-based contrast agent. Furthermore, ejection fraction (EF, %), left ventricular myocardial mass (LVMM) and total infarct size (% of LVMM) were determined with CMR. Clinical follow-up was conducted after a median of 52 months. The primary endpoint was defined as a composite of death, myocardial re-infarction, stroke, repeat revascularization, recurrence of ischemic symptoms, atrial fibrillation, congestive heart failure and hospitalization. Follow-up was completed by 107 patients. 63 pre-defined events occurred during follow-up. Initially, 74 patients showed early MVO. Patients with early MVO had larger infarcts (mean: 24.9 g vs. 15.5 g, p = 0.002) and a lower EF (mean: 39% vs. 46%, p = 0.006). The primary endpoint occurred in 66.2% of patients with MVO and in 42.4% of patients without MVO (p < 0.05). The presence of early MVO was associated with a reduced event-free survival (log-rank p < 0.05). Early MVO was identified as the strongest independent predictor for the occurrence of the primary endpoint in the multivariable Cox regression analysis adjusting for age, ejection fraction and infarct size (hazard ratio: 2.79, 95%-CI 1.25-6.25, p = 0.012). Early MVO, as assessed by first-pass CMR, is an independent long-term prognosticator for morbidity after AMI.

PurposeEndovascular simulation is an established and validated training method, but there is still no proof of direct patient’s benefit, defined as lower complication rate. In this study, the impact of such a training was investigated for rehearsal of patient-specific cases as well as for a structured simulation curriculum to teach angiographer novices.Materials and MethodsA total of 40 patients undergoing a diagnostic neuroangiography were randomized in a training and control group. In all training group patients, the angiographer received a patient-anatomy-specific rehearsal on a high-fidelity simulator prior to the real angiography. Radiation exposure, total duration, fluoroscopy time and amount of contrast agent of the real angiography were recorded. Silent cerebral ischemia was counted by magnetic resonance diffusion-weighted imaging (DWI). Additionally, the first 30 diagnostic neuroangiographies of six novices were compared (ntotal = 180). Three novices had undergone a structured simulation curriculum; three had acquired angiographic skills without simulation.ResultsNo differences were found in the number of DWI lesions or in other quality measures of the angiographies performed with and without patient-specific rehearsal. A structured simulation curriculum for angiographer novices reduced fluoroscopy time significantly and radiation exposure. The curriculum had no influence on the total duration of the examination, the amount of contrast medium or the number of catheters used.ConclusionThere was no measurable benefit of patient-anatomy-specific rehearsal for an unselected patient cohort. A structured simulation-based curriculum to teach angiographic skills resulted in a reduction of fluoroscopy time and radiation dose in the first real angiographies of novice angiographers.Level of EvidenceLevel 4, part 1: randomized trial, part 2: historically controlled study.

Objectives To compare the intravoxel incoherent motion (IVIM) diffusion and perfusion characteristics of nasopharyngeal carcinoma (NPC) and post-chemoradiation fibrosis to aid in their differentiation. Methods Fifty-three (64 %) patients with newly diagnosed NPC and 30 (36 %) patients with biopsy-proven post-chemoradiation fibrosis were recruited into tumour and fibrosis groups respectively. Diffusion-weighted magnetic resonance (MR) imaging was performed using 13 b values (0–1,000 s/mm 2 ). Their respective IVIM parameters ( D , pure diffusion; f , perfusion fraction; D *, pseudodiffusion coefficient) were obtained. Results D and f were significantly lower in NPC ( D  = 0.752 ± 0.194 × 10 -3  mm 2 /s, P <0.001; f  = 0.122 ± 0.095, P <0.001) than in fibrosis ( D  = 1.423 ± 0.364 × 10 -3  mm 2 /s; f  = 0.190 ± 0.120); while D * was significantly higher in NPC (111.366 ± 65.528 × 10 -3  mm 2 /s, P <0.001) than in fibrosis (77.468 ± 62.168 × 10 -3  mm 2 /s). Respective cut-off values with sensitivity, specificity and accuracy were: D  = 1.062 × 10 -3  mm 2 /s (100 %, 100 %, 100 %); f  = 0.132 (66.0 %, 100 %, 78.3 %); D * = 85.283 × 10 -3  mm 2 /s (100 %, 90.7 %, 96.4 %). Conclusion NPC and post-chemoradiation fibrosis have distinctive IVIM parameters. IVIM MR imaging is potentially useful in discrimination between NPC and fibrosis. Key Points • New MRI techniques offer greater help in the assessment of nasopharyngeal carcinoma . • Tumour and post - chemoradiation fibrosis have distinctive intravoxel incoherent motion diffusion / perfusion parameters . • Non - invasive IVIM MRI may help differentiate between tumour and fibrosis . • Pure diffusion is a robust independent discriminating factor which improves diagnostic confidence .

Objectives To evaluate whether careful exercise training improves pulmonary perfusion and blood flow in patients with pulmonary hypertension (PH), as assessed by magnetic resonance imaging (MR). Methods Twenty patients with pulmonary arterial hypertension or inoperable chronic thromboembolic PH on stable medication were randomly assigned to control ( n  = 10) or training groups ( n  = 10). Training group patients received in-hospital exercise training; patients of the sedentary control group received conventional rehabilitation. Medication remained unchanged during the study period. Changes of 6-min walking distance (6MWD), MR pulmonary flow (peak velocity) and MR perfusion (pulmonary blood volume) were assessed from baseline to week 3. Results After 3 weeks of training, increases in mean 6MWD ( P  = 0.004) and mean MR flow peak velocity ( P  = 0.012) were significantly greater in the training group. Training group patients had significantly improved 6MWD ( P  = 0.008), MR flow (peak velocity −9.7 ± 8.6 cm/s, P  = 0.007) and MR perfusion (pulmonary blood volume +2.2 ± 2.7 mL/100 mL, P  = 0.017), whereas the control group showed no significant changes. Conclusion The study indicates that respiratory and physical exercise may improve pulmonary perfusion in patients with PH. Measurement of MR parameters of pulmonary perfusion might be an interesting new method to assess therapy effects in PH. The results of this initial study should be confirmed in a larger study group. Key Points • Quantification of magnetic resonance perfusion is feasible in patients with pulmonary hypertension. • Quantified magnetic resonance perfusion may become useful for non-invasive monitoring of treatment. • Quantification of lung perfusion allows new insights into lung (patho-)physiology of PH. • Careful exercise training improves pulmonary perfusion and blood flow in patients with PH.

Background The aim was to investigate the feasibility of a cardiovascular magnetic resonance (CMR) black-blood thrombus imaging (BBTI) technique, based on delay alternating with nutation for tailored excitation black-blood preparation and a variable flip angle turbo-spin-echo readout, for the diagnosis of acute deep vein thrombosis (DVT) at 1.5 T. Methods BBTI was conducted in 15 healthy subjects and 30 acute DVT patients. Contrast-enhanced CMR venography (CE-CMRV) was conducted for comparison and only performed in the patients. Apparent contrast-to-noise ratios between the thrombus and the muscle/lumen were calculated to determine whether BBTI could provide an adequate thrombus signal for diagnosis. Two blinded readers assessed the randomized BBTI images from all participants and made independent decisions on the presence or absence of thrombus at the segment level. Images obtained by CE-CMRV were also randomized and assessed by the two readers. Using the consensus CE-CMRV as a reference, the sensitivity, specificity, positive and negative predictive values, and accuracy of BBTI, as well as its diagnostic agreement with CE-CMRV, were calculated. Additionally, diagnostic confidence and interobserver diagnostic agreement were evaluated. Results The thrombi in the acute phase exhibited iso- or hyperintense signals on the BBTI images. All the healthy subjects were correctly identified from the participants based on the segment level. The diagnostic confidence of BBTI was comparable to that of CE-CMRV (3.69 ± 0.52 vs. 3.70 ± 0.47). High overall sensitivity (95.2%), SP (98.6%), positive predictive value (96.0%), negative predictive value (98.3%), and accuracy (97.7%), as well as excellent diagnostic and interobserver agreements, were achieved using BBTI. Conclusion BBTI is a reliable, contrast-free technique for the diagnosis of acute DVT at 1.5 T.

Background and Purpose Subpial hemorrhage is a rare form of neonatal stroke, still poorly understood. The aim of this study was to characterize a cohort of term and preterm neonates with subpial hemorrhages and contribute to a better knowledge of this condition. Material and Methods Clinical records and magnetic resonance (MR) imaging data of all neonates with subpial hemorrhage followed at a pediatric hospital between 2010 and 2020 were retrospectively reviewed. Results A total of 10 patients were included in the analysis, 40% of whom were term neonates. Operative vaginal delivery was registered in 30%. Temporal was the most common location of subpial hemorrhage (70%), and all patients displayed underlying brain infarction. A characteristic yin-yang pattern was present in 90% of the study cohort, and ingurgitation of medullary veins on susceptibility weighted imaging in 80%. Cerebellar microbleeds were observed in 60% of neonates, both term and preterm. When available, MR angiography and venography were unremarkable. Patients’ clinical outcome was variable, with early prematurity not associated to worse outcomes. Conclusion Subpial hemorrhage has a distinctive MR pattern, with underlying parenchymal venous infarction, and can occur in term and preterm neonates. This study results suggest an association between subpial hemorrhage and cerebellar microbleeds but further studies are required to confirm it and better understand the pathophysiology of subpial hemorrhage.

Purpose Previous studies have shown that arterial spin-labeling (ASL) has high sensitivity and specificity for detecting dural arteriovenous fistulas (DAVFs). However, in case of jugular venous reflux (JVR), the labeled protons in the jugular vein may lead to a venous hypersignal in the jugular vein, sigmoid, and transverse sinus on ASL images and mimic DAVF. Methods To ascertain this hypothesis, two blinded senior neuroradiologists independently and retrospectively reviewed randomized ASL images and graded the likelihood of DAVF on a 5-point Likert scale in 2 groups of patients: (i) 13 patients with angiographically proven type I DAVF; and (ii) 11 patients with typical JVR diagnosed on the basis of clinical and MR imaging data, first using ASL alone, and second using ASL together with all of the sequences including 4D CE MRA. Result A dural venous ASL signal was seen in 11 patients with type I DAVF and in all the 11 patients with JVR, with no distinctive pattern between the two. The mean Likert score was “very likely” in DAVF and JVR patients when using ASL alone ( k  = 0.71), and “very unlikely” for JVR versus “very likely” for DAVF when using all the sequences available ( k  = 0.92). Conclusion Our study shows that JVR can mimic DAVF on ASL images with potential implications for patient care. The detection of DAVFs should be based on additional MR sequences such as TOF-MRA and 4D CE MRA to exclude JVR and to avoid unnecessary DSAs.

Purpose To evaluate image quality and diagnostic accuracy for acute infarct detection and radiation dose of 70 kVp whole brain CT perfusion (CTP) and CT angiography (CTA) reconstructed from CTP source data. Methods Patients were divided into three groups ( n  = 50 each): group A, 80 kVp, 21 scanning time points; groups B, 70 kVp, 21 scanning time points; group C, 70 kVp, 17 scanning time points. Objective and subjective image quality of CTP and CTA were compared. Diagnostic accuracy for detecting acute infarct and cerebral artery stenosis ≥ 50 % was calculated for CTP and CTA with diffusion weighted imaging and digital subtraction angiography as reference standards. Effective radiation dose was compared. Results There were no differences in any perfusion parameter value between three groups ( P  > 0.05). No difference was found in subjective image quality between three groups ( P  > 0.05). Diagnostic accuracy for detecting acute infarct and vascular stenosis showed no difference between three groups ( P  > 0.05). Compared with group A, radiation doses of groups B and C were decreased by 28 % and 37 % (both P  < 0.001), respectively. Conclusion Compared with 80 kVp protocol, 70 kVp brain CTP allows comparable vascular and perfusion assessment and lower radiation dose while maintaining high diagnostic accuracy in detecting acute infarct. Key Points • 70 kVp whole brain CTP can provide diagnostic image quality . • 70 kVp CTP diagnostic accuracy was maintained vs. 80 kVp protocol . • 70 kVp CTP radiation doses were lower than 80 kVp protocol .