ABSTRACT
BACKGROUND AND PURPOSE: Alzheimer disease (AD) is accompanied by macroscopic atrophy on volumetric MR imaging. A few studies have also demonstrated reduction in magnetization transfer ratio (MTR), suggesting microstructural changes in remaining brain tissue. This study assessed the value of measuring MTR in addition to volumetric MR in differentiating patients with AD from control subjects. MATERIALS AND METHODS: Volumetric T1-weighted images and 3D MTR maps were obtained from 18 patients with AD and 18 age-matched control subjects. Whole-brain (WB) and total hippocampal (Hc) volumes were measured using semiautomated techniques and adjusted for total intracranial volume. Mean MTR was obtained for WB and in the Hc region. Histogram analysis was performed for WB MTR. Among patients, associations between volumetric and MTR parameters and the Mini-Mental State Examination (MMSE) were explored. RESULTS: Patients with AD had significantly reduced WB volume (P<.0001) and mean WB MTR (P=.002) and Hc volume (P<.0001) and Hc mean MTR (P<.0001) compared with control subjects. Histogram analysis of WB MTR revealed significant reduction in the 25th percentile point in patients with AD (P=.03). Both WB volume and mean MTR were independently associated with case-control status after adjusting for the other using linear regression models. However, measuring Hc mean MTR added no statistically significant discriminatory value over and above Hc volume measurement alone. Of all MR imaging parameters, only WB volume was significantly correlated with MMSE (r=0.47, P=.048). CONCLUSIONS: This study demonstrates the independent reduction of WB volume and mean MTR in AD. This suggests that the 2 parameters reflect complementary aspects of the AD pathologic lesion at macrostructural and microstructural levels.
Subject(s)
Alzheimer Disease/pathology , Brain/pathology , Magnetic Resonance Imaging , Aged , Atrophy , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Sensitivity and SpecificityABSTRACT
Three patients with probable dementia with Lewy bodies (DLB) experienced worsening delusions and visual hallucinations as a result of memantine therapy. Significant resolution occurred once treatment was discontinued. Caution is required when prescribing memantine to patients with possible DLB.
Subject(s)
Hallucinations/chemically induced , Lewy Body Disease/drug therapy , Memantine/adverse effects , Schizophrenia, Paranoid/chemically induced , Age of Onset , Aged , Antiparkinson Agents/adverse effects , Antiparkinson Agents/therapeutic use , Brain/drug effects , Brain/pathology , Brain/physiopathology , Cognition Disorders/etiology , Cognition Disorders/physiopathology , Disease Progression , Humans , Lewy Body Disease/physiopathology , Magnetic Resonance Imaging , Male , Memantine/therapeutic use , Middle Aged , Paranoid Disorders/chemically induced , Psychomotor Agitation/etiologyABSTRACT
BACKGROUND: Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL), or Nasu-Hakola disease, is a presenile dementia associated with loss of myelin, basal ganglia calcification, and bone cysts. It is caused by recessively inherited mutations in two genes encoding subunits of a cell membrane-associated receptor complex: TREM2 and DAP12. The clinical course of PLOSL has not been characterized in a series of patients with TREM2 mutations. METHODS: The authors compare neurologic and neuroradiologic follow-up data of six patients carrying TREM2 mutations with PLOSL due to defective DAP12 genes. The authors review the known mutations in these two genes. RESULTS: Mutations in DAP12 and TREM2 result in a uniform disease phenotype. In Finnish and Japanese patients with PLOSL, DAP12 mutations predominate, whereas TREM2 is mutated more frequently elsewhere. CONCLUSIONS: Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy should be considered in adult patients under age 50 years with dementia and basal ganglia calcification. Radiographs of ankles and wrists, and DNA test in uncertain cases, confirm the diagnosis.
