Differentiating Parkinson's disease motor subtypes using automated volume-based morphometry incorporating white matter and deep gray nuclear lesion load.

BACKGROUND: Periventricular leukoaraiosis may be an important pathological change in postural instability gait disorder (PIGD), a motor subtype of Parkinson's disease (PD). Clinical diagnosis of PIGD may be challenging for the general neurologist. PURPOSE: To evaluate 1) the utility of a fully automated volume-based morphometry (Vol-BM) in characterizing imaging diagnostic markers in PD and PIGD, including, 2) novel deep gray nuclear lesion load (GMab), and 3) discriminatory performance of a Vol-BM model construct in classifying the PIGD subtype. STUDY TYPE: Prospective. SUBJECTS: In all, 23 PIGD, 21 PD, and 20 age-matched healthy controls (HC) underwent MRI brain scans and clinical assessments. FIELD STRENGTH/SEQUENCE: 3.0T, sagittal 3D-magnetization-prepared rapid gradient echo (MPRAGE), and fluid-attenuated inversion recovery imaging (FLAIR) sequences. ASSESSMENT: Clinical assessment was conducted by a movement disorder neurologist. The MR brain images were then segmented using an automated multimodal Vol-BM algorithm (MorphoBox) and reviewed by two authors independently. STATISTICAL TESTING: Brain segmentation and clinical parameter differences and dependence were assessed using analysis of variance (ANOVA) and regression analysis, respectively. Logistic regression was performed to differentiate PIGD from PD, and discriminative reliability was evaluated using receiver operating characteristic (ROC) analysis. RESULTS: Significantly higher white matter lesion load (WMab) (P < 0.01), caudate GMab (P < 0.05), and lateral and third ventricular (P < 0.05) volumetry were found in PIGD, compared with PD and HC. WMab, caudate and putamen GMab, and caudate, lateral, and third ventricular volumetry showed significant coefficients (P < 0.005) in linear regressions with balance and gait assessments in both patient groups. A model incorporating WMab, caudate GMab, and caudate GM discriminated PIGD from PD and HC with a sensitivity = 0.83 and specificity = 0.76 (AUC = 0.84). DATA CONCLUSION: Fast, unbiased quantification of microstructural brain changes in PD and PIGD is feasible using automated Vol-BM. Composite lesion load in the white matter and caudate, and caudate volumetry discriminated PIGD from PD and HC, and showed potential in classification of these disorders using supervised machine learning. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2020;51:748-756.

Utility of lumbar puncture after a normal brain computed tomography scan in patients presenting to the emergency department with suspected subarachnoid haemorrhage: A new more rational approach?

OBJECTIVE: The diagnostic approach for patients presenting to EDs with headaches suspicious for subarachnoid haemorrhage (SAH) remains challenging. Modern third-generation computed tomography (CT) has been shown to be extremely sensitive in identifying SAH and may eliminate the need for lumbar puncture (LP) which is an invasive, time-consuming procedure with limited accuracy and complications. The aim of this study is to assess the utility of LP in patients being evaluated for possible SAH in the ED after a negative non-contrast CT scan of the brain, as well as addressing the knowledge gap in regard to rational diagnostics among clinicians. METHODS: We conducted a retrospective data analysis of patients being evaluated for possible SAH between June 2013 and June 2018 across three EDs in Victoria, Australia. A diagnosis of SAH was defined by SAH on CT or an abnormal cerebrospinal fluid result in conjunction with positive results on cerebral angiography. A follow-up period of 6 months was chosen. RESULTS: A total of 4407 patients met inclusion criteria; 397 (9%) patients were diagnosed with SAH on CT. A total of 388 patients underwent LP and 778 were admitted to hospital for further investigations and management. A total of 2613 patients discharged from ED without LP remained well at 6 months from their initial presentation, but 230 cases were lost to follow up. One patient died from haemorrhagic stroke during his third hospitalisation. A single patient demonstrated a true positive LP after a normal CT brain. CONCLUSION: LP is not required in all patients with suspected SAH who have a negative CT scan. There are defining patient characteristics that can be used to risk stratify patients and may eliminate the need for LP.