Journal of Neuroimaging最新文献

Introduction: The venous outflow profile (VOP) is a crucial yet often overlooked aspect affecting stroke outcomes. It plays a major role in the physiopathology of acute cerebral ischemia, as it accounts for both the upstream arterial collaterals and cerebral microperfusion. This enables it to circumvent the limitations of various arterial collateral evaluation systems, which often fail to consider impaired autoregulation and its impact on cerebral blood flow at the microcirculatory levels. In this narrative review, we will highlight the different parameters and modalities used to assess the VOP in acute ischemia.

Vo assessment with different modalities: CT parameters include cortical vein opacification score, interhemispheric difference of composite scores of the draining veins classifications on single-phase CT angiography (CTA), as well as the extent and velocity of optimal cortical venous filling on multiphase CTA. Differences in contrast administration and acquisition time render the single-phase CTA parameters less reliable. Perfusion parameters are semiautomated, thus offering greater reproducibility. These include time to peak and prolonged venous transit. Finally, the venous transit time is an MRI parameter.

Associations and prognostic implications: VOP parameters' significance lies in their potential to predict tissue fate and, subsequently, clinical outcomes. Recent studies indicate that favorable VOP is independently associated with slower rates of infarct edema progression, smaller infarct volumes, and higher rates of functional independence after 90 days. Moreover, it is considered a predictor of recanalization success and the first-pass effect during mechanical thrombectomy. Conversely, an unfavorable VOP predicts futile recanalization and indicates a higher risk of reperfusion hemorrhage. Our aim is to explore these prognostic implications and their relevance in determining the utility of intracranial intervention.

Background and purpose: Tinnitus is a condition in which individuals perceive sounds, such as ringing or buzzing, without any external source. Although the exact cause is not fully understood, recent studies have indicated the involvement of nonauditory brain structures, including the limbic system. We aimed to compare the volumes of specific brain structures between patients with tinnitus and controls.

Methods: Voxel-based morphometry and subfield volumetry were applied to analyze the brain structures of 53 patients with tinnitus and 52 age- and sex-matched controls. The volumes of the amygdala, hippocampus, and thalamus were measured and compared between the groups.

Results: Patients with tinnitus had larger volumes in the whole amygdala, basal nucleus, right lateral nucleus, and left paralaminar nucleus compared with controls. In addition, the subiculum head, left fimbria, and left presubiculum head in the hippocampus were larger in patients with tinnitus. No differences were found in the total thalamic volume or thalamic subnuclei between groups. The gray matter volumes in the thalamus, amygdala, and hippocampus were significantly high in the tinnitus group. The cortical thicknesses of both of the marginal branches of the cingulate sulcus, the left superior parietal lobule, and the left subparietal sulcus were also high in the tinnitus group.

Conclusions: These findings indicate the involvement of the limbic system in tinnitus, and enhance our understanding of the condition. The subfield volumetry technique used in this study may aid in identifying the structural differences associated with specific neurological and psychiatric conditions.

Background and purpose: While the pulsatility index (PI) measured by transcranial Doppler (TCD) has broader associations with outcomes in neurocritical care, its use in monitoring delayed cerebral infarction (DCI) in patients with aneurysmal subarachnoid hemorrhage (SAH) is not endorsed by current clinical guidelines. Recognizing that arterial pressure gradient (ΔP) can be estimated using PI, we investigated the potential significance of TCD-estimated ΔP.

Methods: In this observational study of 186 SAH patients, we recorded the mean cerebral blood flow velocity (mCBFV) and PI values from the middle cerebral artery, along with corresponding blood pressures. Using a previously reported mathematical model, we estimated ΔP by dividing pulse pressure by PI. We investigated the association between ΔP and mCBFV values and two acute phase complications of SAH-DCI and angiographic vasospasm. Additionally, we explored the association between DCI, vasospasm, and 90-day functional outcome.

Results: Elevated ΔP was associated with DCI (odds ratio [OR] 1.021, 95% confidence interval [CI] 1.004-1.039, p = 0.014) but not vasospasm (OR 1.006, 95% CI 0.991-1.022, p = 0.402). Elevated mCBFV was associated with vasospasm (OR 1.037, 95% CI 1.017-1.057, p < 0.001) but not DCI (OR 0.998, 95% CI 0.979-1.018, p = 0.873). DCI (OR 29.380, 95% CI 2.930-294.615, p = 0.004), rather than vasospasm (OR 0.695, 95% CI 0.120-4.043, p = 0.686), was associated with functional outcome.

Conclusions: Increased ΔP, rather than elevated mCBFV, was associated with DCI. While elevated mCBFV was associated with vasospasm, it was not associated with DCI. Hence, TCD-estimated ΔP may serve as a predictor for the DCI in SAH patients, a condition that impacts long-term outcome.

Background and purpose: Peak width of skeletonized mean diffusivity (PSMD) is a novel marker of white matter damage, which may be related to small vessel disease. This study aimed to investigate the presence of white matter damage in patients with isolated rapid eye movement sleep behavior disorder (RBD) using PSMD.

Methods: We enrolled patients with newly diagnosed isolated RBD confirmed by polysomnography and age- and sex-matched healthy controls. Diffusion tensor imaging (DTI) was conducted using a 3-Tesla MRI scanner. We measured the PSMD based on DTI in several steps, including preprocessing, skeletonization, application of a custom mask, and histogram analysis, using the Functional Magnetic Resonance Imaging of the Brain Software Library program. We compared the incidence of PSMD between patients with RBD and healthy controls and performed a correlation analysis between PSMD and clinical factors in patients with RBD.

Results: Thirty patients with isolated RBD and 41 healthy controls were enrolled. The PSMD was significantly higher in patients with RBD than that in the healthy controls (3.078 vs. 2.746 × 10^-4 mm²/s, p = 0.001). In addition, PSMD positively correlated with age in patients with RBD (r = 0.477, p = 0.007). However, PSMD was not associated with other clinical or polysomnographic factors.

Conclusion: Patients with isolated RBD had a higher PSMD than healthy controls, indicating the evidence of white matter damage in patients with RBD. This finding highlights the potential of PSMD as a marker for detecting white matter damage, which may be related to small vessel diseases, in patients with sleep disorders.

Background and purpose: The safety and effectiveness of endovascular techniques in elderly patients with large vessel occlusion (LVO) remain controversial. We investigated the angiographic and clinical outcomes of nonagenarians treated with different endovascular techniques using a balloon guide catheter (BGC), distal aspiration catheter (DAC), and/or stent retriever (SR).

Methods: We analyzed the data from the Registry of Combined versus Single Thrombectomy Techniques (ROSSETTI) of consecutive nonagenarian patients with anterior circulation LVO and compared the outcomes of those treated with BGC+noDAC+SR (101-group), BGC+DAC+SR (111-group), and noBGC+DAC+SR (011-group). Demographic, clinical, angiographic, and clinical outcome data (National Institute of Health Stroke Scale score at 24 h [24h-NIHSS] and modified Rankin Scale score at 3 months) were compared. Predictors of the first-pass effect (FPE), defining Modified Treatment In Cerebral Ischemia 2c-3 (mTICI 2c-3) after one pass, were explored.

Results: Of the 4111 patients from the ROSSETTI registry, 243 nonagenarians (68.7% female) were included in the analysis. The distribution of endovascular techniques was 101-group (61.4%), 111-group (15.6%), and 011-group (23%). The 101-group and 111-group had significantly shorter procedural times than the 011-group. The 111-group had a higher FPE rate, a lower number of passes, and a higher rate of final mTICI ≥2c than the other groups. The 24h-NIHSS score was significantly lower in the 111-group. In multivariate analysis, the only independent predictor for FPE was the BGC+DAC+SR endovascular technique (odds ratio 2.74 [confidence interval 1.16-6.47]; p = 0.021).

Conclusions: The addition of a DAC to a BGC increases the likelihood of FPE in nonagenarians with anterior circulation LVO SR-based thrombectomy for acute stroke.

Background and purpose: Prolonged length of stay (LOS) following a stroke is associated with unfavorable clinical outcomes. Factors predicting LOS in medium vessel occlusion (MeVO), impacting up to 40% of acute ischemic stroke (AIS) cases, remain underexplored. This study aims to investigate the predictors of LOS in AIS-MeVO.

Methods: We conducted a retrospective analysis of prospectively maintained stroke databases, comprising AIS cases with MeVO in the anterior circulation, assessed by adequate CT perfusion (CTP). Baseline and clinical data were obtained from electronic health records. Alberta Stroke Program Early CT Scores (ASPECTS) were calculated from non-contrast head CT. The perfusion mismatch volume (time to maximum > 6 s minus relative cerebral blood flow <30%) volume was reported from CTP. Multiple regression was employed to examine the relationship between baseline parameters and hospital LOS.

Results: A total of 133 patients (median age 71 [interquartile range 63-80] years, 59.4% females) were included in the study cohort. The perfusion mismatch volume significantly positively correlated with LOS (r = 0.264, p = 0.004). After adjusting for age, sex, hypertension, diabetes, prior stroke or transient ischemic attack, admission NIHSS, ASPECTS, Tan score, intravenous thrombolysis, mechanical thrombectomy (MT), and hemorrhagic transformation, a larger mismatch volume remained independently associated with longer hospital stays (β = 0.209, 95% confidence interval [CI] 0.006-0.412, p = 0.045). Additional significant determinants of longer hospital stay included admission NIHSS (β = 0.250, 95% CI: 0.060-0.440, p = 0.010) and MT (β = 0.208, 95% CI: 0.006-0.410, p = 0.044). Among patients who underwent MT (n = 83), multiple regression analysis incorporating both perfusion mismatch volume and admission NIHSS revealed that perfusion mismatch volume remained independently associated with LOS (β = 0.248, 95% CI: 0.019-0.471, p = 0.033), while admission NIHSS did not retain significance (β = 0.208, 95% CI: 0.019-0.433, p = 0.071).

Conclusions: In our cohort of AIS patients with MeVO in the anterior circulation, and particularly in those who underwent MT, the perfusion mismatch volume serves as an independent predictor of LOS. These findings offer critical valuable insights in clinical assessments and decision-making protocols of MT in AIS-MeVO.

Background and purpose: MRI is crucial for multiple sclerosis (MS), but the relative value of portable ultra-low field MRI (pULF-MRI), a technology that holds promise for extending access to MRI, is unknown. We assessed white matter lesion (WML) detection on pULF-MRI compared to high-field MRI (HF-MRI), focusing on blinded assessments, assessor self-training, and multiplanar acquisitions.

Methods: Fifty-five adults with MS underwent pULF-MRI following their HF-MRI. Two neuroradiologists independently assessed pULF-MRI images in an evaluation process, including initial assessment blinded to HF-MRI, self-training with reference to HF-MRI and evaluation of 20 cases with additional T2-fluid-attenuated inversion recovery in an additional plane. A third rater conducted cross-referenced analysis with HF-MRI data to determine true-positive lesions, false-positive areas, and case-level sensitivity and positive predictive value.

Results: The mean age of participants was 50 years (standard deviation: 11; 74% women). Initially, Rater 2 marked more false-positive areas than Rater 1 (p = 0.003). After self-training, both raters embraced a conservative approach, with Rater 2 marking fewer false-positive areas (p = 0.01). Both raters maintained 100% case-level sensitivity and positive predictive value for detecting at least one WML, particularly in periventricular areas. Multiplanar acquisitions reduced both false-positive areas and true-positive lesions. True-positive lesions and false-positive areas had similar contrast-to-noise ratios in the juxtacortical region (p = 0.73) but not in periventricular, deep parenchymal regions (p = 0.004, p = 0.01).

Conclusion: With adequate training, radiological interpretation of pULF-MRI has high sensitivity and positive predictive value for MS lesions but should be approached conservatively. These results suggest utility for patient triage, potentially reducing diagnostic delay, and screening high-risk individuals.