Cerebral artery signal intensity gradient from Time-of-Flight Magnetic Resonance Angiography and clinical outcome in lenticulostriate infarction: a retrospective cohort study.

Purpose: Lenticulostriate infarction requires further research of arterial hemodynamic factors, as the disease is diagnosed in the absence of major arterial stenosis or cardioembolism. Methods: In this multicenter retrospective cohort study, we included patients who were hospitalized for lenticulostriate infarction from January 2015 to March 2021 at three stroke centers in South Korea. We obtained hemodynamic information on cerebral arteries using signal intensity gradient (SIG), an in-vivo approximated wall shear stress (WSS) derived from Time-of-Flight Magnetic Resonance Angiography (TOF-MRA). A favorable outcome was defined as a modified Rankin Scale of 0 to 2 at hospital discharge. Results: A total of 294 patients were included, of whom 146 (49.7%) had an unfavorable outcome. The unfavorable outcome group showed significantly lower SIG in both middle cerebral arteries (MCAs) than the favorable group (5.2 ± 1.2 SI/mm vs. 5.9 ± 1.2, p < 0.001), and similar findings were observed in other cerebral arteries. The SIGs in both MCAs were independently associated with favorable outcome, with an odds ratio of 1.42 (95% confidence interval, 1.11-1.80; p = 0.005) for the right MCA and 1.49 (95% CI, 1.15-1.93; p = 0.003) for the left MCA, after adjusting for potential confounders. Similar findings were observed in other cerebral artery SIGs. Conclusion: Cerebral artery SIG from TOF-MRA was significantly associated with short-term functional outcomes in patients with lenticulostriate infarction. Further studies are needed to investigate the temporal relationships of SIG in patients with cerebral infarction.

Renal Dysfunction Is Associated with Middle Cerebral Artery Pulsatility Index and Total Burden of Cerebral Small Vessel Disease.

BACKGROUND AND PURPOSE: Renal dysfunction is known to affect vasculature and lead to systemic arterial stiffness. It also independently increases the risk of cerebral small vessel disease (cSVD) and stroke. We aimed to examine the effect of renal dysfunction on cerebral hemodynamics and the burden of cSVD. METHODS: Of the 412 patients admitted to Seoul National University Hospital, between May 2015 and 2019, with lacunar infarction and no major intracranial arterial stenosis observed on magnetic resonance angiography, we included 283 patients who had undergone a transcranial Doppler (TCD) ultrasound after 72 h of stroke onset. The patients were divided into renal dysfunction (estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m2 at admission) and control (eGFR ≥60 mL/min/1.73 m2) groups. We investigated the correlations between renal function, the pulsatility index (PI), and the total MRI burden of cSVD. Furthermore, multivariate analysis was performed to assess the association between renal dysfunction and the PI of the middle cerebral artery (MCA) measured through TCD ultrasound. RESULTS: Among the total patients, 74 (26.1%) had renal dysfunction (eGFR <60 mL/min/1.73 m2 at admission). Patients with renal dysfunction were significantly older, showed higher pulse pressure, and had a higher prevalence of hypertension, diabetes mellitus, and coronary artery disease. Renal dysfunction was significantly associated with higher distal cerebrovascular flow resistance (median PI 1.12, interquartile range [IQR]: 0.85-1.57 vs. controls 0.84, IQR: 0.54-1.22; p < 0.001). Also, patients with renal dysfunction had a significantly higher total MRI burden of cSVD (median cSVD score 2, IQR: 1-3 vs. controls median score 1, IQR: 0-2; p < 0.001). There was an inverse proportional relationship between the PI and eGFR. Finally, multivariate analysis showed renal dysfunction (adjusted odds ratio: 4.516, 95% confidence interval: 1.051-20.292) and older age (adjusted odds ratio: 1.076, 95% confidence interval: 1.038-1.114) as independent predictors of a high PI. CONCLUSIONS: Renal dysfunction is independently associated with a high PI of MCA. Renal dysfunction leads to systemic arterial stiffness including stiffness in cerebral arteries, thus increasing the burden of cSVD. Therefore, noninvasive screening for high PI by TCD in kidney failure patients might be helpful.

Diffusion-Weighted Imaging Patterns According to the Right-to-Left Shunt Amount in Cryptogenic Stroke.

BACKGROUND: Although patent foramen ovale (PFO) is considered to be the main cause of cryptogenic stroke, it is difficult to define "true" PFO-related stroke. OBJECTIVE: In this study, we evaluated comprehensive diffusion-weighted imaging (DWI) findings in patients with cryptogenic stroke according to the right-to-left shunt (RLS) amounts on transcranial Doppler (TCD) sonography. METHODS: We assessed consecutive patients with cryptogenic stroke between October 2010 and 2018. The RLS amount on TCD was assessed according to the International Consensus Criteria (ICC). Massive RLS was defined as the highest category of ICC (Curtain pattern). We assessed DWI findings, including the location of lesions, involved vascular territory, and DWI lesion patterns. RESULTS: A total of 100 consecutive patients with cryptogenic stroke were assessed, and PFO was found in 59 patients. In multivariable analyses, massive RLS was noted to be positively associated with the presence of cortical lesion (adjusted OR [aOR] 15.75, 95% CI 1.94-127.71, p = 0.010), multiple territory involvement (aOR 5.24, 95% CI 1.57-17.53, p = 0.007), and number of DWI lesions (beta 0.713, 95% CI 0.245 to 1.181, p = 0.003) after adjusting for confounders. Conversely, massive RLS showed inverse correlations with posterior circulation involvement (aOR 0.22, 95% CI 0.06-0.87, p= 0.031) and number of large DWI lesions (beta -0.328, 95% CI -0.629 to -0.026, p = 0.034). CONCLUSIONS: We demonstrated that massive RLS on TCD was associated with multiple, small-scattered cortical lesion in patients with cryptogenic stroke. These DWI pattern is highly suggestive of PFO-related stroke.