Yen Kung Chen

Regional CBF changes in Parkinson’s disease: a correlation with motor dysfunction

PurposeThe purpose of this study was to further localize cerebral perfusion abnormalities, and to better correlate these abnormalities with the clinical severity of Parkinson’s disease (PD).MethodsA single-photon emission computed tomography (SPECT) study was performed on 27 patients with PD and 24 age-matched controls. SPECT images were spatially normalized, concatenated, and then decomposed using Infomax independent component analysis (ICA). The resulting image components were separated by logistic regression into two subspaces: “disease-related” components whose subject weights differed between groups, and “disease-unrelated” components. The resultant regional cerebral blood flow (rCBF) subspace images were normalized to global CBF for each subject, and then processed using statistical parametric mapping to compare rCBF values between PD and control subjects.ResultsIn the disease-related image subspace, patients with PD exhibited significantly higher adjusted rCBF in the putamen, globus pallidum, thalamus, brainstem, and the anterior lobe of the cerebellum, and significant hypoperfusion in the parieto-temporo-occipital cortex, the dorsolateral prefrontal cortex, the insula, and the cingulate gyrus. The motor Unified Parkinson’s Disease Rating Scale scores correlated negatively with rCBF in the insula and cingulate gyrus. In the disease-unrelated image subspace, no brain voxels exhibited a significant group difference.ConclusionICA-based separation of normalized images into disease-related and disease-unrelated subspaces revealed many disease-related group blood flow differences. The regions revealed by ICA are consistent with the current model of PD. These rCBF changes in PD have not been fully demonstrated in any single functional imaging study previously.

F-18 FDG PET in detecting uterine leiomyoma

PURPOSEnUterine leiomyoma, benign tumors of the human uterus, are clinically apparent in about 25% of women and the most common solid pelvic tumors. The purpose of this study was to investigate the F-18 2-fluoro-2-deoxy-D-glucose (FDG) uptake in the uterine leiomyoma and assess the correlation between the intensity of FDG uptake in the uterine leiomyomas and menstrual cycle.nnnMETHODSnA total of 589 charts of healthy females examined by whole body FDG positron emission tomography (PET) for health screening examination were reviewed retrospectively. Twenty-two of them were suspected gynacecological tumors and referred to the department of gynacecology to ascertain the nature of the causes. Final diagnosis as uterine leiomyomas were made based on uterine sonography, pelvic computed tomography, or pelvic magnetic resonance imaging scans. We defined FDG uptake as Grade I when FDG uptake was less than liver uptake, Grade II when FDG uptake was equal to liver uptake, and Grade III when FDG uptake was greater than liver uptake. The menstrual cycle was recorded on the day of performing FDG PET in premenopausal women.nnnRESULTSnThe FDG uptake in the uterine region is Grade I in three of these 22 females (13.65%), Grade II in 16 (72.7%), and Grade III in 3 (13.65%).nnnCONCLUSIONnThere is no significant correlation between the intensity of FDG uptake in the uterine leiomyomas and menstrual cycle (P=.914).

Perfusion status of the stroke-like lesion at the hyperacute stage in MELAS

Hypoperfusion on single-photon emission computed tomography (SPECT) of the stroke-like lesion (SLL) at the hyperacute stage of mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS) is considered to be a supportive evidence of the mitochondrial angiopathy theory. Our objectives were to examine whether other neuroimages, especially transcranial color-coded sonography (TCCS), done at the hyperacute stage of stroke-like episode (SLE) is consistent with hypoperfusion of the SLL. We reviewed the magnetic resonance imaging (MRI), SPECT, cerebral angiography, and TCCS of a patient with MELAS syndrome, all of which were performed at the hyperacute stage of one SLE. MRI on the 1st day post SLE showed right temporoparietal lesion with vasogenic edema. SPECT on the 2nd day showed focal decreased uptake of technetium-99m hexamethylpropyleneamine oxime ((99m)Tc-HMPAO) in the same region, but cerebral angiography and TCCS on the 3rd day showed increased regional cerebral blood flow (rCBF) and distal arteriole dilation in the same region. TCCS can delineate increased rCBF of the SLL at the hyperacute stage of SLE. We propose that the discrepancy between the decreased (99m)Tc-HMPAO uptake and increased rCBF might be caused by mitochondrial dysfunction. The phenomenon of hypoperfusion on SPECT might be caused by cell dysfunction but not decreased rCBF. We suggest that SPECT can be complemented by angiography and TCCS in future studies to delineate the perfusion status of SLLs.

Exposing the evil in the dark: The usefulness of delayed-phase FDG PET scan to enhance the detectability of tiny residual skull base osteosarcoma initially concealed by adjacent high physiological brain activity

A 50-year-old man had an osteosarcoma in the skull base after surgery and adjuvant chemotherapy. Residual malignancy in the skull base was still suspected 6 months after the anticancer therapy. An FDG PET/CT was performed and a special abnormal finding in the prior skull base lesion site was noted. The abnormality was not found in the early phase scan but appeared in the delayed phase scan. The subsequent biopsy of the abnormality confirmed the presence of residual malignancy.

Incidental Second and Third Primary Cancers Asynchronously Detected by FDG-PET in a Patient with Breast Cancer

The frequency of double primary cancers synchronously found in an individual has been increasing. However, synchronous or asynchronous triple primary cancers have rarely been reported. A 69-year-old female received an operation for right breast cancer and subsequent chemotherapy in 2001. During the 5-year follow-up period, second and third primary cancers were asynchronously detected by FDG-PET. Lung cancer was identified and surgery was performed in May and June 2003, respectively. Follow-up FDG-PET performed in March 2006 revealed a biologically active (viable) residual tumor in the perihilar region of the right lung. Surprisingly, an additional focal area with increased FDG uptake in the ascending colon was noted. The patient was symptom-free and had a normal serum CEA level. The lesion was proved to be colon cancer, a third primary cancer asynchronously found in this patient. Whole-body FDG-PET is not only an important tool for the early detection of viable residual tumors in patients with malignancy but also early detection of asynchronously developing cancers in other parts of the body.