Morphologic Evolution of Recent Small Sub-Cortical Infarcts and Adjacent White Matter in the Basal Ganglia in a Chinese Cohort
Cerebral small vessel disease (CSVD) represents a significant contributor to stroke, cognitive decline, and motor dysfunction, particularly in aging populations. Among its imaging hallmarks, recent small sub-cortical infarcts (RSSI) are critical markers of vascular pathology. However, data on the morphologic evolution of RSSI, especially in Chinese populations, remain limited. This study investigates the outcomes of RSSI in the basal ganglia and their impact on adjacent white matter, providing insights into the progression of CSVD and its clinical implications.
Study Design and Methodology
This retrospective cohort study enrolled 78 patients from the First Affiliated Hospital of Zhengzhou University (January 2014–June 2018) with a single, acute RSSI in the basal ganglia confirmed by magnetic resonance imaging (MRI). Inclusion criteria required a follow-up MRI scan, while exclusion criteria eliminated cases with non-CSVD etiologies, neurodegenerative diseases, or poor image quality.
Baseline clinical data included age, sex, vascular risk factors (hypertension, diabetes, dyslipidemia, smoking, alcohol use), and stroke severity measured by the National Institutes of Health Stroke Scale (NIHSS). MRI protocols utilized a 3.0 Tesla scanner with sequences such as T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), fluid-attenuated inversion recovery (FLAIR), and diffusion-weighted imaging (DWI). Infarct size was measured in three dimensions on axial DWI or FLAIR, with the maximum diameter recorded.
Morphologic outcomes of RSSI were categorized as:
- Cavitation: Cerebrospinal fluid (CSF)-equivalent signal on T1WI, T2WI, and FLAIR.
- White matter hyperintensity (WMH): Non-cavitated hyperintense lesion on FLAIR/T2WI.
- Absent: Complete resolution on follow-up imaging.
New WMH formation adjacent to the index infarct was assessed independently of diffuse white matter changes. CSVD markers, including lacunes, enlarged perivascular spaces (EPVS), and WMH progression, were evaluated using validated scales (Fazekas for WMH; STRIVE criteria for EPVS). Statistical analyses compared demographic, clinical, and imaging variables across outcome groups and identified predictors of new WMH via logistic regression.
Key Findings
Evolution of RSSI in the Basal Ganglia
At a median follow-up of 304 days (range: 124–552 days), the baseline median infarct diameter decreased significantly from 10.40 mm (range: 7.60–12.56 mm) to 7.54 mm (range: 5.31–10.18 mm) (P < 0.001). The morphologic outcomes were heterogeneous:
- Cavitation: 46/78 (59.0%) cases showed partial or complete cavitation, with 18/46 (39.1%) fully cavitated.
- WMH: 19/78 (24.4%) lesions transitioned to non-cavitated WMH.
- Absent: 13/78 (16.7%) infarcts resolved entirely.
Follow-up duration significantly influenced outcomes (P < 0.001). Longer intervals correlated with cavitation or resolution (median 304 days for cavitation vs. 92 days for WMH vs. 626 days for absent lesions). However, no demographic or clinical factors (age, sex, vascular risks, baseline NIHSS) predicted specific infarct outcomes.
New White Matter Hyperintensity Formation
New WMH adjacent to the index infarct developed in 8/78 (10.3%) patients. Univariate analysis revealed no associations with age, sex, or vascular risk factors. However, WMH progression (defined by Rotterdam criteria) and cavitation were significantly linked to new WMH (P = 0.030 and P = 0.035, respectively). Multivariate logistic regression identified WMH progression as an independent predictor (odds ratio [OR] = 15.95; 95% confidence interval [CI] = 1.65–153.99; P = 0.017), even after adjusting for confounders like age and infarct size.
CSVD Burden and Imaging Correlates
At baseline, 52/78 (66.7%) patients had lacunes, 30/78 (38.5%) exhibited extensive deep WMH, and 26/78 (33.3%) showed moderate-to-severe EPVS in the centrum semiovale. WMH progression occurred in 13/78 (16.7%) cases, underscoring the dynamic nature of CSVD.
Discussion
Heterogeneity in Infarct Outcomes
The study highlights the variable fate of RSSI in the basal ganglia. Over half of the infarcts cavitated, while nearly 17% resolved completely, suggesting that small sub-cortical infarcts may shrink or disappear over time. This contrasts with prior studies reporting cavitation rates of 28%–94%, likely due to differences in follow-up duration, infarct location, and imaging protocols. The basal ganglia’s dense white matter architecture and perforating arteriole vulnerability may explain the high cavitation rate, as tissue loss and ex-vacuo effects dominate healing.
New WMH as a Marker of CSVD Progression
The formation of new WMH adjacent to RSSI (10.3% of cases) signals localized white matter degeneration, distinct from diffuse CSVD. This phenomenon may reflect Wallerian degeneration or ischemic injury extending beyond the infarct core. The strong association between WMH progression and new lesion formation (OR = 15.95) suggests shared mechanisms, such as blood-brain barrier disruption or inflammatory cascades. These findings align with CADASIL studies, where small infarcts induced cortical thinning via white matter tract degeneration.
Clinical Implications
Cavitation and new WMH formation may serve as imaging biomarkers for CSVD severity. While cavitation indicates irreversible tissue damage, perilesional WMH could predict cognitive or motor decline, necessitating longitudinal studies. The lack of traditional risk factor associations (e.g., hypertension) underscores the complexity of CSVD pathophysiology, where genetic and microenvironmental factors may dominate.
Limitations and Future Directions
The retrospective design, small sample size, and variable follow-up intervals limit generalizability. Fixed-time imaging and prospective cohorts are needed to standardize outcome assessments. Additionally, advanced techniques like diffusion tensor imaging could elucidate microstructural white matter changes post-infarct.
Conclusion
This study demonstrates that RSSI in the basal ganglia frequently evolve into cavities or resolve entirely, with a subset triggering adjacent WMH formation. WMH progression emerges as a critical predictor of localized white matter injury, highlighting its role in CSVD worsening. These insights underscore the need for early intervention targeting white matter integrity to mitigate CSVD-related disability.
doi.org/10.1097/CM9.0000000000001041
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