Won Sang Jung

Regional Cortical Thickness and Subcortical Volume Changes Are Associated with Cognitive Impairments in the Drug-Naive Patients with Late-Onset Depression

Previous studies have shown an association between late-onset depression (LOD) and cognitive impairment in older adults. However, the neural correlates of this relationship are not yet clear. The aim of this study was to investigate the differences in both cortical thickness and subcortical volumes between drug-naive LOD patients and healthy controls and explore the relationship between LOD and cognitive impairments. A total of 48 elderly, drug-naive patients with LOD and 47 group-matched healthy control subjects underwent 3T MRI scanning, and the cortical thickness was compared between the groups in multiple locations, across the continuous cortical surface. The subcortical volumes were also compared on a structure-by-structure basis. Subjects with LOD exhibited significantly decreased cortical thickness in the rostral anterior cingulate cortex, the medial orbitofrontal cortex, dorsolateral prefrontal cortex, the superior and middle temporal cortex, and the posterior cingulate cortex when compared with healthy subjects (all p<0.05, false discovery rate corrected). Reduced volumes of the right hippocampus was also observed in LOD patients when compared with healthy controls (p<0.001). There were significant correlations between memory functions and cortical thickness of medial temporal, isthmus cingulate, and precuneus (p<0.001). This study was the first study to explore the relationships between the cortical thickness/subcortical volumes and cognitive impairments of drug-naive patients with LOD. These structural changes might explain the neurobiological mechanism of LOD as a risk factor of dementia.

Bronchiolitis obliterans after allogenic bone marrow transplantation: HRCT findings.

Objective To evaluate the high resolution computed tomography (HRCT) findings of bronchiolitis obliterans (BO) after bone marrow transplantation (BMT). Materials and Methods During the past three years, 11 patients were diagnosed as having BO after BMT when they developed irreversible air flow obstruction, with an FEV1 value of less than 80% of the baseline value, without any clinical evidence of infection. All 11 patients underwent HRCT, of whom eight also underwent follow-up HRCT. The HRCT images were assessed retrospectively for the presence of decreased lung attenuation, segmental or subsegmental bronchial dilatation, diminution of peripheral vascularity, centrilobular nodules, and branching linear structure on the inspiratory images. The lobar distribution of the decreased lung attenuation and bronchial dilatation was also examined. The presence of air trapping was investigated on the expiratory images. The interval changes of the HRCT findings were evaluated in those patients who had follow-up images. Results Abnormal HRCT findings were present in all cases; the most common abnormalities were decreased lung attenuation (n=11), subsegmental bronchial dilatation (n=6), diminution of peripheral vascularity (n=6), centrilobular nodules or branching linear structure (n=3), and segmental bronchial dilatation (n=3). Expiratory air trapping was noted in all patients. The decreased lung attenuation and bronchial dilatations were more frequent or extensive in the lower lobes. Interval changes were found in all patients with follow-up HRCT: increased extent of decreased lung attenuation (n=7); newly developed or progressed bronchial dilatation (n=4); and increased lung volume (n=3). Conclusion HRCT scans are abnormal in patients with BO, with the most commonly observed finding being areas of decreased lung attenuation. While the HRCT findings are not specific, it is believed that their common features can assist in the diagnosis of BO in BMT recipients.

Aberrant topographical organization in gray matter structural network in late life depression: a graph theoretical analysis.

BACKGROUND Although previous studies on late life depression (LLD) have shown morphological abnormalities in frontal-striatal-temporal areas, alterations in coordinated patterns of structural brain networks in LLD are still poorly understood. The aim of this study was to investigate differences in gray matter structural brain network between LLD and healthy controls. METHODS We used gray matter volume measurement from magnetic resonance imaging to investigate large-scale structural brain networks in 37 LLD patients and 40 normal controls. Brain networks were constructed by thresholding gray matter volume correlation matrices of 90 regions and analyzed using graph theoretical approaches. RESULTS Although both LLD and control groups showed a small-world organization of group networks, there were no differences in the clustering coefficient, the path length, and the small-world index across a wide range of network density. Compared with controls, LLD patients showed decreased nodal betweenness in the medial orbitofrontal and angular gyrus regions. In addition, LLD patients showed hub regions in superior temporal gyrus and middle cingulate gyrus, and putamen. On the other hand, the control group showed hub regions in the medial orbitofrontal gyrus, middle cingulate gyrus, and cuneus. CONCLUSION Our findings suggest that the gray matter structural networks are not globally but regionally altered in LLD patients. This multivariate structural analysis using graph theory might provide a more appropriate paradigm for understanding complicated neurobiological mechanism of LLD.

Automated hippocampal subfields segmentation in late life depression

Although a few automated hippocampal subfields segmentation methods have been developed, there has been no in vivo Magnetic Resonance Imaging (MRI) study on the hippocampal subfields volumes of Late Life Depression (LLD). The aim of this study was to investigate the hippocampal subfields volume differences between LLD subjects and healthy elderly controls using an automated hippocampal subfields segmentation technique. Thirty subjects with LLD and 30 group-matched healthy control subjects underwent 3T MRI scanning, and hippocampal subfields volumes were measured and compared between the groups. Subjects with LLD exhibited significant hippocampal volume reductions in the total hippocampus, subiculum, and Cornu Ammonis (CA) 2-3 areas compared with healthy subjects (uncorrected, p<0.001). This study is the first to elaborate the subfields volume differences of both hippocampi between controls and LLD patients. These structural changes in the hippocampal presubiculum, subiculum, and CA2-3 areas might be at the core of the underlying neurobiological mechanisms of hippocampal dysfunction in LLD.

Relationships between hippocampal shape and cognitive performances in drug-naïve patients with Alzheimer's disease

Previous studies provided hippocampal shape analysis of Alzheimers disease (AD) patients using automated segmentation techniques. However, the relationships between the hippocampal deformations and various cognitive impairments were not clear. The aim of this study was to investigate hippocampal shape changes and their relationship to cognitive impairments. Fifty-one drug-naïve patients with AD and 50 group-matched healthy control subjects underwent 3T MRI scanning, and the hippocampal volumes and deformations were compared between the groups. Additionally, we explored the correlation pattern between the hippocampal deformations and the cognitive dysfunctions in AD using the Korean version of the Consortium to Establish a Registry for Alzheimers Disease (CERAD-K). AD subjects exhibited significant hippocampal deformations in the cornu ammnonis (CA1) and subiculum areas compared to those in healthy subjects (p<0.05, false discovery rate (FDR) corrected). Significant correlations were observed between hippocampal deformations in CA1 and subiculum areas and verbal immediate recall, verbal delayed recall, verbal recognition memory, and constructional recall scores (p<0.05, FDR corrected). This study was the first to explore the relationships between hippocampal deformations and various cognitive impairments of drug-naïve patients with AD. These structural changes in hippocampal CA1 and subiculum areas might be the core of the underlying neurobiological mechanisms of hippocampal dysfunction and their relevance to the various cognitive dysfunctions in AD.

Automated hippocampal subfield segmentation in amnestic mild cognitive impairments.

Although a few automated hippocampal subfield segmentation methods have been developed, the effects of amnestic mild cognitive impairment (aMCI) on the hippocampal subfield volumes on magnetic resonance imaging (MRI) are not clear. The aim of this study was to investigate the hippocampal subfield volume changes and their relationships with various neuropsychological tests in aMCI using an automated hippocampal subfield segmentation technique. Forty-five subjects with aMCI and 49 group-matched healthy control subjects underwent 3-tesla MRI scanning, and hippocampal subfield volumes were measured and compared. Additionally, we explored the correlation pattern between hippocampal subfield volumes and the Korean version of the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD-K) neuropsychological test scores in aMCI subjects. Subjects with aMCI exhibited significant hippocampal volume reductions in the presubiculum, subiculum and cornu ammonis 2–3 areas compared with healthy subjects. In addition, we also found significant positive correlations between presubiculum and subicular area volumes and the CERAD-K verbal and visuospatial delayed recall scores in aMCI. This study was the first to explore the relationships between hip-pocampal subfield volumes and various types of cognitive performances in aMCI. These structural changes might be at the core of the underlying neurobiological mechanisms of hippocampal dysfunction in aMCI.

Hippocampal shape and cognitive performance in amnestic mild cognitive impairment.

Previous studies have carried out hippocampal shape analysis of amnestic mild cognitive impairment (aMCI) patients using automated segmentation techniques. However, the relationships between hippocampal deformations and various episodic memory impairments were not clear. The aim of this study was to investigate hippocampal shape changes and their relationships with various episodic memory impairments in aMCI. Hippocampal volumes and deformations were compared between the aMCI and the controls. In addition, we explored the correlation pattern between hippocampal deformations and cognitive dysfunctions in aMCI using a comprehensive neuropsychological battery. Patients with aMCI exhibited significant hippocampal deformations in the right cornu ammonis 1 (CA1) and subiculum areas compared with healthy individuals. Significant correlations were observed between constructional recall scores and the right CA1 and subiculum areas in aMCI. Verbal delayed recall scores were also significantly correlated with the left CA1 and subiculum areas in aMCI. This study was the first to explore the relationships between hippocampal deformations and various types of cognitive performances in aMCI. These structural changes in the hippocampal CA1 and subiculum areas might be at the core of underlying neurobiological mechanisms of hippocampal dysfunction and their relevance to verbal and visuospatial delayed recall in aMCI.

Automated quantification of amyloid positron emission tomography: a comparison of PMOD and MIMneuro

ObjectiveThe aim of this study was to examine and compare two automated quantitative software tools (PMOD and MIMneuro) for the quantification of amyloid positron emission tomography (PET).MethodsA total of 30 subjects—15 Alzheimer’s disease (AD) patients and 15 cognitively normal age- and sex-matched controls—were enrolled. All subjects underwent structural volumetric magnetic resonance imaging (MRI) and amyloid PET scans with F-18 florbetaben. Regional standardized uptake value ratios (SUVRs) using the cerebellar cortex as a reference region were obtained using PMOD and MIMneuro.ResultsThe SUVRs using both PMOD and MIMneuro showed high discriminatory power between the AD patients and cognitively normal controls. While PMOD and MIMneuro yielded significantly different SUVRs in some brain regions, the two methods had good overall agreement.ConclusionMIMneuro provides comparable performance to PMOD without the need to acquire brain MRI. Therefore, MIMneuro might be suitable for clinical use to determine amyloid positivity.

A Rare Case of Recurrent Myoid Hamartoma Mimicking Malignancy: Imaging Appearances

Myoid hamartoma is an uncommon type of breast hamartoma and its recurrence is very rare. We report the imaging appearance of an unusual case of recurrent myoid hamartoma of the breast mimicking malignancy in a 43-year-old woman. Although the mammographic and ultrasonographic findings have long been described in the literature, MR finding with a dynamic study has not, to the best of our knowledge, been reported previously.

Cerebral Vascular Burden on Hippocampal Subfields in First-onset Drug-naïve Subjects with Late-Onset Depression

BACKGROUND Although there is substantial evidence of associations between frontal-striatal circuits and cerebral vascular burden in late-onset depression (LOD), relationships between vascular burden and hippocampal subfields are not clear. The purpose of this study was to investigate relationships between cerebral vascular burden and hippocampal subfield volume in LOD patients. METHODS Fifty subjects with LOD and 50 group-matched healthy control subjects underwent magnetic resonance imaging scanning. Hippocampal subfields volumes were measured and compared between the groups. In addition, association patterns between white matter hyperintensity (WMH) volumes, clinical measures and hippocampal subfield volumes were investigated in the LOD group. RESULTS Subjects with LOD exhibited significant hippocampal volume reductions in the total hippocampus, cornu ammonis (CA) 1 and 3 and dentate gyrus (DG) areas compared with healthy subjects. Total WMH volume was negatively correlated with left total hippocampal volume and CA1 in the LOD group. In addition, depression severity was negatively associated with left and right CA3 volumes in the LOD group. LIMITATION Our findings of distinctive relationships between WMH and hippocampal subfields demonstrate a simple correlation, but do not prove causation CONCLUSION: This study is the first to elaborate distinctive association patterns between hippocampal subfield volumes and cerebral vascular burden in LOD. These structural changes in the hippocampal CA1, CA3 and DG areas might be at the core of the underlying neurobiological mechanisms of hippocampal dysfunction in LOD. However, longitudinal studies will be needed to identify the mechanisms of these structural changes.