Clinical manifestations and magnetic resonance imaging features of spinal cord infarction.

BACKGROUND AND OBJECTIVE: Spinal cord infarction (SCI) is a rare type of stroke, with no proposed classification or diagnostic criterium widely accepted and used in daily clinical practice currently. We try to explore the clinical manifestations and MRI features of SCI for improving the accurate diagnosis of SCI. METHODS: Retrospectively analyzed the clinical data, MRI features, laboratory findings and outcomes of 40 patients who had been consecutively diagnosed with SCI in our hospital from June 2016 to January 2022. RESULTS: Most of the SCI (92.5%) occurred at the level of T8-L2 and C4-T4. Transverse infarction (52.5%) and ASA territory infarction (27.5%) were the most common patterns. Longitudinally extensive lesions were noticed in 67.5% of the SCI and it might be a risk factor of poor prognosis (OR=21.11, 95%CI 2.14-208.29). Restricted diffusion of the SCI lesion occurred in 8h and a few lasted up to 60 days. All SCI showed spinal cord edema, accompanied by enhancement of the ventral cauda equina (13.8%), weakened enhancement of the dorsal venous plexus (44.8%), and vertebral infarction (25%). Most patients developed a stroke-like onset (92.5%) after movement (57.5%), with definite pain in the trunk or limbs (67.5%) and dissociative sensory disturbance (60.0%). The main etiologies of them include vascular abnormalities (45%) and iatrogenic injuries (15%). CONCLUSION: An MRI classification of SCI based on the spinal cord blood supply was proposed. Restricted diffusion and co-existing abnormality of vertebral body and cauda equina may be the key neuroimaging feature for SCI diagnosis. Detailed history of vascular diseases or triggering factors are also helpful.

MRI features and evolution of autoimmune glial fibrillary acidic protein astrocytopathy: A retrospective cross-sectional and longitudinal study.

BACKGROUND: Autoimmune glial fibrillary acidic protein astrocytopathy (AGA) is a relatively novel disease. The early diagnosis of this inflammatory central nervous system (CNS) disorder remains challenging. OBJECTIVES: We aimed to explore the imaging manifestations and evolution of AGA to facilitate its successful diagnosis and monitoring. METHODS: From January 2016 to January 2021, a total of 15 consecutive patients, who were hospitalised in our institution and confirmed AGA clinically, were enrolled in this IRB-approved retrospective study. All clinical features and MRI manifestations were analysed cross-sectionally and longitudinally. Distribution, morphology, enhancement pattern and evolution of AGA lesions were assessed visually and evaluated semi-quantitatively by calculating the burden of disease (BOD) and the signal intensity ratio (SIR). Chi-square, Mann-Whitney U and Kolmogorov-Smirnov Z tests were performed for lesion patterns' statistical comparison. RESULTS: Fever, limb weakness, headache and cognitive impairment were the most common symptoms in AGA. 14 patients were initially misdiagnosed as infection (n = 9), demyelination (n = 4) or infarction (n = 1). The median time interval from onset to confirmed AGA diagnosis was 46 days. Both BOD and SIR progressed in the natural course and were relieved after immunotherapy on MRI. Meningeal enhancement, one of the most common MRI findings in patients with AGA (100%), relieved faster than intraparenchymal enhancement (p <0.001) and peri­ventricular radial linear (PVRL) enhancement (p <0.001) after the initiation of immunotherapy. Non-enhanced lesions had lower BOD (p <0.001) and were relieved slower (p <0.001) than enhanced ones. CONCLUSIONS: MRI provides valuable neuroradiological indicators for the diagnosis and follow-up of AGA. The CNS enhancement patterns (meningeal / PVRL) facilitate the early diagnosis and treatment response monitoring of AGA, while lesion manifestation in the spinal cord contributes to the follow-up. The evolution inconsistency of AGA lesions in different regions may be attributed to the discrepancy within glial fibrillary acidic protein subtypes.

Combining in vivo proton exchange rate (k ex) MRI with quantitative susceptibility mapping to further stratify the gadolinium-negative multiple sclerosis lesions.

Background: Conventional gadolinium (Gd)-enhanced MRI is currently used for stratifying the lesion activity of multiple sclerosis (MS) despite limited correlation with disability and disease activity. The stratification of MS lesion activity needs further improvement to better support clinics. Purpose: To investigate if the novel proton exchange rate (k ex ) MRI combined with quantitative susceptibility mapping (QSM) may help to further stratify non-enhanced (Gd-negative) MS lesions. Materials and methods: From December 2017 to December 2020, clinically diagnosed relapsing-remitting MS patients who underwent MRI were consecutively enrolled in this IRB-approved retrospective study. The customized MRI protocol covered conventional T2-weighted, T2-fluid-attenuated-inversion-recovery, pre- and post-contrast T1-weighted imaging, and quantitative sequences, including k ex MRI based on direct-saturation removed omega plots and QSM. Each MS lesion was evaluated based on its Gd-enhancement as well as its susceptibility and k ex elevation compared to the normal appearing white matter. The difference and correlation concerning lesion characteristics and imaging contrasts were analyzed using the Mann-Whitney U test or Kruskal-Wallis test, and Spearman rank analysis with p < 0.05 considered significant. Results: A total of 322 MS lesions from 30 patients were identified with 153 Gd-enhanced and 169 non-enhanced lesions. We found that the k ex elevation of all lesions significantly correlated with their susceptibility elevation (r = 0.30, p < 0.001). Within the 153 MS lesions with Gd-enhancement, ring-enhanced lesions showed higher k ex elevation than the nodular-enhanced ones' (p < 0.001). Similarly, lesions with ring-hyperintensity in QSM also had higher k ex elevation than the lesions with nodular-QSM-hyperintensity (p < 0.001). Of the 169 Gd-negative lesions, three radiological patterns were recognized according to lesion manifestations on the k ex map and QSM images: Pattern I (k ex + and QSM+, n = 114, 67.5%), Pattern II (only k ex + or QSM+, n = 47, 27.8%) and Pattern III (k ex - and QSM-, n = 8, 4.7%). Compared to Pattern II and III, Pattern I had higher k ex (p < 0.001) and susceptibility (p < 0.05) elevation. The percentage of Pattern I of each subject was negatively correlated with the disease duration (r = -0.45, p = 0.015). Conclusion: As a potential imaging biomarker for inflammation due to oxidative stress, in vivo k ex MRI combined with QSM is promising in extending the clinical classification of MS lesions beyond conventional Gd-enhanced MRI.