Mingming Huang

The glymphatic system (GS) serves as the brain's waste clearance pathway, with dysfunction implicated in neurodegenerative disorders—particularly cerebral small vessel disease (CSVD). As hypertension is a modifiable risk factor strongly linked to CSVD progression, we compared magnetic resonance imaging‐derived (MRI‐derived) GS metrics between hypertensive and normotensive CSVD patients. So, in this study, we retrospectively analyzed 72 clinically diagnosed CSVD patients (37 hypertensive [CSVD_HT ⁺ ], 35 normotensive [CSVD_HT ⁻ ]), and 40 age‐matched healthy controls (HCs). Key MRI‐derived GS indices included: perivascular space volume fraction (PVS‐VF), diffusivity along perivascular spaces (ALPS index), free water in white matter (FW‐WM), and choroid plexus volume (Chp). CSVD patients exhibited abnormal MRI‐derived indices, Compared to CSVD_HT ⁻ individuals, CSVD_HT ⁺ were characterized by lower ALPS index, higher FW‐WM and hypertrophy of Chp. Random systolic blood pressure (SBP) negatively correlated with ALPS index ( r = −0.220, p = 0.055), while positively correlating with FW‐WM ( r = 0.460, p < 0.001), and Chp volume ( r = 0.310, p = 0.006). Cognitive assessments revealed associations between ALPS index and memory scores ( r = 0.280, p = 0.020). These findings suggest that elevated SBP exacerbates GS impairment in CSVD, underscoring the critical role of blood pressure management. Longitudinal studies are needed to confirm these observations.

Few comparative studies have assessed metabolic brain changes in cognitive impairment among neurodegenerative disorders, and the posterior cingulate cortex (PCC) is a metabolically active brain region with high involvement in multiple cognitive processes. Therefore, in this study, metabolic abnormalities of the PCC were compared in patients with mild cognitive impairment (MCI) due to Parkinson’s disease (PD) or Alzheimer’s disease (AD), as examined by proton magnetic resonance spectroscopy (¹H-MRS). Thirty-eight patients with idiopathic PD, including 20 with mild cognitive impairment (PDMCI) and 18 with normal cognitive function (PDN), 18 patients with probable mild cognitive impairment (ADMCI), and 25 healthy elderly controls (HCs) were recruited and underwent PCC ¹H-MRS scans. Compared with HCs, patients with PDMCI exhibited significantly reduced concentrations of N-acetyl aspartate (NAA), total NAA (tNAA), choline (Cho), glutathione (GSH), glutamate + glutamine (Glx) and total creatine (tCr), while ADMCI cases exhibited significantly elevated levels of myo-inositol (Ins) and Ins/tCr ratio, as well as reduced NAA/Ins ratio. No significant metabolic changes were detected in PDN subjects. Compared with ADMCI, reduced NAA, Ins and tCr concentrations were detected in PDMCI. Besides, ROC curve analysis revealed that tCr concentration could differentiate PDMCI from PDN with an AUC of 0.71, and NAA/Ins ratio could differentiate patients with MCI from controls with normal cognitive function with an AUC of 0.74. Patients with PDMCI and ADMCI exhibited distinct PCC metabolic ¹H-MRS profiles. The findings suggested cognitively normal PD patients with low NAA and tCr in the PCC might be at risk of preclinical PDMCI, and Ins and/or NAA/MI ratio in the PCC should be reconsidered a possible biomarker of preclinical MCI in clinical practice. So, comparing PCC’s ¹H-MRS profiles of cognitive impairment among neurodegenerative illnesses may provide useful information for better defining the disease process and elucidate possible treatment mechanisms.

BACKGROUND: To explore the different patterns of cortical thickness and subcortical volume changes between Parkinson disease (PD) subtypes by structural magnetic resonance imaging (MRI).METHODS:We enrolled 48 clinically confirmed PD patients, including 23 tremor dominant (TD) and 25 postural instability gait dominant (PIGD) subtypes, and 32 matched healthy control (HC) volunteers were also collected, all subjects underwent 3.0 Tesla high-resolution structural MRI scanning. Cortical thickness and subcortical volumetric analysis were estimated using an automated Computational Anatomy Toolbox (CAT12) toolbox.Results:Compared with the HC group, PIGD patients had significantly thinning cortical thickness in multiple brain regions, such as bilateral inferiorparietal, paracentral, precuneus, superiorfrontal, caudalmiddlefrontal, posteriocingulate, parahippacampal, lateraloccipital and right superiortemporal, supramarginal and parsorbitals. TD patients had slightly thinning focal cortical thickness in bilateral posteriocingulate, left inferioparietal and right precuneus. PIGD patients had thinner cortical thickness in left caudalmiddlefrontal, parahippacampal and right isthmuscingulate and lateraloccipital than TD patients. In addition, subcortical volume atrophy was identified in the bilateral hippocampus and bilateral amygdala of the patients with PIGD, only right hippocampus changes were found in the TD group. Moreover, the largest area under the ROC curve of hippocampus and atrophy ratio, cortical thickness in region of interest (ROI) and combination of hippocampus ratio, atrophy ratio and cortical thickness in ROIs which for distinguish PIGD from TD were 0.733, 0.912 and 0.999 respectively.Conclusions:Morphometric abnormalities were greater in the PIGD than that in the TD subtype, the disparate patterns of cortical and subcortical degeneration had a potential possibility to distinguish the PD subtypes by MRI perspective in clinical practice.

Lymphomatosis cerebri (LC) is a rare variant of primary central nervous system lymphoma (PCNSL), characterized by diffuse infiltration without the formation of a discrete mass. The diagnosis of LC is a challenge because the imaging findings are atypical for lymphoma. The purpose of present study is to investigate MRI characteristics and clinical features of LC and potentially facilitate an early and accurate diagnosis of this often-missed disease. Seven patients (average 44 years, 19–58 years) with LC proved basing on MRI and histology were retrospectively reviewed the clinical data and cerebral MR imaging findings. The common presenting symptoms were cognitive decline, behavioral disturbance, gait disturbance. All patients had both deep and lobar lesion distribution, and two of them had infratentorial involvement. Lack of contrast enhancement and subtle patchy enhanced pattern were observed in two and three patients, respectively. The remaining two patients presented multiple patchy enhancement. Most of the lesions were slightly hyperintense to normal brain on DWI as well as hyperintense on ADC maps. Three patients presented a pattern of marked decrease of NAA/Cr, increase of Cho/Cr, and two of the three cases showed increased Lip/Cr and Lac/Cr on MRS. We conclude that diffuse bilateral lesions especially in deep and lobar region including white and gray matter, without enhancement or with patchy enhancement, marked decrease of NAA/Cr and increase of Cho/Cr, and increased Lip/Cr and Lac/Cr are suggestive of LC. Prompt recognition of these imaging patterns may lead to early diagnosis of LC and brain biopsy with improved prognosis.