Direct comparison study between FDG-PET and IMP-SPECT for diagnosing Alzheimer's disease using 3D-SSP analysis in the same patients.

PURPOSE: The purpose of this study was to evaluate and compare the diagnostic ability of 2-[(18)F]-fluoro-2-deoxy-D: -glucose (FDG) positron emission tomography (PET) and N-isopropyl-p-(123)I iodoamphetamine single photon emission computed tomography (IMP-SPECT) using three-dimensional stereotactic surface projections (3D-SSP) in patients with moderate Alzheimer's disease (AD). MATERIALS AND METHODS: FDG-PET and IMP-SPECT were performed within 3 months in 14 patients with probable moderate AD. Z-score maps of FDG-PET and IMP-SPECT images of a patient were obtained by comparison with data obtained from control subjects. Four expert physicians evaluated and graded the glucose hypometabolism and regional cerebral blood flow (rCBF), focusing in particular on the posterior cingulate gyri/precunei and parietotemporal regions, and determined the reliability for AD. Receiver operating characteristic (ROC) curves were applied to the results for clarification. To evaluate the correlation between two modalities, the regions of interest (ROIs) were set in the posterior cingulate gyri/precunei and parietotemporal region on 3D-SSP images, and mean Z-values were calculated. CONCLUSION: No significant difference was observed in the area under the ROC curve (AUC) between FDG-PET and IMP-SPECT images (FDG-PET 0.95, IMP-SPECT 0.94). However, a significant difference (P < 0.05) was observed in the AUC for the posterior cingulate gyri/precuneus (FDG-PET 0.94, IMP-SPECT 0.81). The sensitivity and specificity of each modality were 86%, and 97% for FDG-PET and 70% and 100% for IMP-SPECT. We could find no significant difference between FDG-PET and IMP-SPECT in terms of diagnosing moderate AD using 3D-SSP. There was a high correlation between the two modalities in the parietotemporal region (Spearman's r = 0.82, P < 0.001). The correlation in the posterior cingulate gyri/precunei region was lower than that in the parietotemporal region (Spearman's r = 0.63, P < 0.016).

Usefulness of FDG PET for diagnosis and radiotherapy of the patient with malignant lymphoma involving bone marrow.

We experienced a case of relapsed malignant lymphoma with multiple bone marrow or bone lesions. The case was diagnosed as follicular lymphoma by cytological biopsy of the right iliac bone, with (67)Ga scintigraphy showing abnormal, intense uptake in multiple bones. After about 10 months of systemic chemotherapy, a relapse was suspected because of pain in the bilateral legs and a high level of lactate dehydrogenase. Assessment of the lesions in the patient was difficult by computed tomography because the affected sites were localized mainly in the bone marrow. (18)F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) was useful for detecting accurately the relapse sites in the bone marrow and enabled us to determine the field for radiotherapy. There are only a few reports of FDG-PET findings for such bone marrow malignant lymphomas. Therefore, we report the findings of FDG-PET for this case and review some of the literature about bone marrow lymphomas.

An abnormal accumulation of fluorine-18-FDG PET in cytomegalovirus enteritis--a case report.

The source of a fever of unknown origin (FUO) and watery diarrhea in a 63-yr-old female with a history of disturbance of consciousness due to moyamoya disease was examined. Fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET), colonoscopy, blood analysis, and determination of cytomegalovirus (CMV) antigenemia were performed. FDG was found to be accumulated in the wall of a dilated colon, and extended from the transverse to sigmoid colon. Colonoscopy revealed edematous, inflammatory, and punched out lesions in accordance with the areas of abnormal FDG uptake. A biopsy specimen showed the antibody of CMV in the colonic mucosa, and CMV antigenemia was detected by an immunohistochemical assay using a monoclonal antibody for CMV pp65 antigen. From these findings, we strongly suspected CMV enteritis.

Findings of fluorine-18-FDG PET in extranodal origin lymphoma--in three cases of diffuse large B cell type lymphoma.

F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) is an excellent modality for non-invasive functional imaging of malignant lymphoma and is highly sensitive and specific for the detection of lymphoma lesions. Here, we report the findings of FDG-PET for three cases of diffuse large B cell type lymphoma (DLBCL) with extranodal tumors in the breast, stomach, and liver plus spleen, respectively. The whole body FDG-PET findings showed no evidence of lymph node (LN) involvement or distant metastasis. Strong FDG accumulations were observed in the only extranodal sites by whole body FDG-PET. Therefore, we could confirm that these cases were extranodal primary origins. Whole body PET is useful to determine the primary sites, that is, extranodal origin DLBCL with its clear images.

Development of a practical image-based scatter correction method for brain perfusion SPECT: comparison with the TEW method.

PURPOSE: An image-based scatter correction (IBSC) method was developed to convert scatter-uncorrected into scatter-corrected SPECT images. The purpose of this study was to validate this method by means of phantom simulations and human studies with 99mTc-labeled tracers, based on comparison with the conventional triple energy window (TEW) method. METHODS: The IBSC method corrects scatter on the reconstructed image I(mub)AC with Chang's attenuation correction factor. The scatter component image is estimated by convolving I(mub)AC with a scatter function followed by multiplication with an image-based scatter fraction function. The IBSC method was evaluated with Monte Carlo simulations and 99mTc-ethyl cysteinate dimer SPECT human brain perfusion studies obtained from five volunteers. The image counts and contrast of the scatter-corrected images obtained by the IBSC and TEW methods were compared. RESULTS: Using data obtained from the simulations, the image counts and contrast of the scatter-corrected images obtained by the IBSC and TEW methods were found to be nearly identical for both gray and white matter. In human brain images, no significant differences in image contrast were observed between the IBSC and TEW methods. CONCLUSION: The IBSC method is a simple scatter correction technique feasible for use in clinical routine.