Clinical Application of FDG-PET in Biliary- pancreatic Malignancy

PURPOSE: This study was done to review our clinical experience of fluorodeoxyglucose (FDG)-positron emission tomography (PET) in biliary-pancreatic malignancies, and evaluated its diagnostic accuracy and usefulness. METHODS: FDG-PET was performed in 15 patients with biliary-pancreatic malignancies, to determine the extent of the disease (n=9) and to detect the recurrence (n=6). RESULTS: Of the 9 patients with a suspected loco-regional spread, 6 patients were disclosed by FDG-PET as having multiple metastasis to the regional lymph nodes and extraperitoneal organs, but the other 3 showed no evidence of regional or distant metastasis. Thus, FDG-PET performed preoperatively to estimate the extent of the disease, showed sensitivity and specificity of 100%, respectively. However, for the detection of a recurrent disease only 3 out of 5 with recurrent diseases were detected by FDG-PET (sensitivity: 60%). FDG-PET revealed one suspected recurrent lesion, but a computed tomography (CT) scan showed no evidence of a recurrence. Due to the 2 false-negative results, the overall sensitivity and specificity of this study were 81.8 (9/11) and 100% (4/4), respectively. CONCLUSION: Unnecessary surgical procedures were avoided in 6 cases, and 3 curative surgeries aborted through the use of FDG-PET. Despite the lack of cases, FDG-PET was useful in estimating the extent of a disease, but was unsatisfactory in detecting a recurrent disease compared to CT. Coupled with conventional imaging, FDG-PET may also provide more helpful information for biliary-pancreatic malignancies as well.

Cerebrovascular Reactivity in Dementia of Alzheimer's Type Assessed by Acetaxolamide Brain SPECT / 신경정신의학

OBJECTIVES: The purpose of this study was to investigate the abnormality of cerebrovascular reactivity in patients with dementia of Alzheimer's type by the acetazolamide brain SPECT, which has been used in the assessment of cerebrovascular diseases. METHODS: Eighteen patients with dementia of Alzheimer's type, as diagnosed by the criteria of DSM-IV and NINCDS-ADRDA, and ten normal comparison subjects were recruited. They were rated by Mini-Mental Status Examination, Mattis Ddementia Rating Scale, and Hamilton Depression Rating Scale. Acetazolamide brain SPECT scans of dementia patients and comparison subjects were analyzed by 3-dimensional volume of interest method. RESULTS: The results were as follows. There were significant differences in the values of cerebrovascular reactivity between the two groups. The cerebrovascular reactivity of dementia patients was significantly decreased in the right frontal lobes, and increased in left temporal lobe, compared to comparison subjects(p<0.05). CONCLUSION: These results imply the possible role of the abnormality of cerebrovascular reactivity in the pathophysiology of dementia of Alzheimer's type.

18FFDG PET Study of Cerebral Glucose Metabolism in Obsessive-Compulsive Disorder / 신경정신의학

OBJECTIVE: Functional imaging studies on obsessive-compulsive disorder(OCD) subjects have repeatedly reported increased metabolism in orbitofrontal lobes and caudate nucleus, resulting in the "frontal-subcortical" circuit abnormality theory. Limitations of the previous studies to date include little consideration for the duration of illness, and the use of regions of interest methods, as an image analysis method. Our study objectives are 1) to include the duration of illness as an important study variable, and 2) to use Statistical Parametric Mapping(SPM) method in order to tap relations between the brain function and the psychopathology and symptoms of OCD. METHOD: The [18] fluorodeoxyglucose positron emission tomography(FDG-PET) scans of OCD subjects and normal comparison subjects, as diagnosed by the Structured Clinical Interview for DSM-IV(SCID-IV), were analyzed using SPM. RESULTS: 1) Comparison of OCD and control groups: OCD subjects had significantly decreased metabolism in both parietal lobes and didn't have any areas of increased metabolism in comparison to comparison subjects(p<0.01). Four OCD subjects with the illness duration of 10 years or longer, had significantly increased metabolism in both orbitofrontal lobes(p<0.01). OCD subjects whose illness duration is shorter than 10 years didn't have any areas of increased metabolism and had significantly decreased parietal lobe metabolism, as in the analyses of all subjects(p<0.01). 2) Correlation analysis between areas and symptom severity: Metabolism of both thalamic areas showed significant positive correlation with Yale-Brown Obsessive-Compulsive Scale(Y-BOCS) scores(p<0.01). Metabolism of right parietal area showed significant negative corre-lation with Y-BOCS scores(p<0.01). CONCLUSIONS: The current findings suggest that the increased metabolism in orbitofrontal lobe, previously reported, may be a secondary phenomenon due to the extended illness duration and that decreased metabolism in the parietal lobes are primary abnormality in OCD subjects. Thus Baxter's fronto-subcortical circuit theory should be extended into "fronto-parietal" complex theory, which includes the parietal lobes.

Brain Single Photon Emission Computed Tomography Findings in Elderly Depressive Pseudodementia Patients / 신경정신의학

OBJECTS: Through comparison of the 99mTc-HMPAO SPECT image of depressive pseudo-dementia group with those of control group(depression group free from cognitive unpairment) and DAT(Dementia of Alzheimer's type), we tried to see part of pathophysiology of the depressive pseudodementia of the elderly. METHODS: The subjects consisted off patients with dementia of Alzheimer type(DAT group), 7 patients with depression free from cognitive impairment(depression group), 7 patients with depressive pseudodementia(depressive pseudodementia group), and 4 normal controls. Depression patients were diagnosed according to DSM III-R DAT patients were diagnosed by DSM III-R and NINCDS-ADRDA criteria of DAT. All were rated with Hamilton Rating Scale for Depression and Mini Mental State Exam. All underwent 99mTc-HMPAO SPECT scan. The images of each group were analysed using SPM of Friston, which compares the images on voxel-by-voxel basis. RESULTS: The results were as follows 1) DAT group showed significant decrease in cerebral blood flow (CBF) compared with controls in the right frontal region, the right temporal region, and both temporal regions(p<0.05). 2) Depression group showed significant decrease in CBF in the left frontal region(p<0.05). 3) Depressive pseudodementia group showed significant decrease in CBF compared with controls in the right temporal region and the left parietal region(p<0.05). 4) Depressive pseudodementia group showed significant decrease in CBF compared with depression group in the right temporal region and both parietal regions(p<0.05). CONCLUSION: Depressive pseudodementia group showed decreased CBF in temporo-parietal region, similar to that of the DAT group. This result supports the hypothesis that depressive psuedodementia includes a subgroup of patients with early-stage primary dementia.

Assessment of Ventricular Function and Phase Abnormality by Gated Blood Pool Scan in Dilated Cardiomyopathy

Gated blood pool scan(GBPS) may be used for evaluating patients with dilated cardiomyopathy(DCM) where it can assist in the diagnosis, and evaluation of severity, disease progression or therapeutic efficacy. In addition to the routine parameters that have been available by GBPS, relatively simple mathematical manipulations of the equilibrium time activity curve can derive parameters relating to the degree and sequence of ventricular emptying. This first harmonic phase analysis may enable quantitative and more specific measurements of wall motion abnormalities in DCM and may thus be useful for more accurate assessments in these patients. Thus, in an attempt to evaluate the findings of phase analysis in DCM and to determine their possible usefulness in this entity, we measured parameters of phase analysis from the resting GBPS of 25 DCM patients and 11 normal controls, and compared these with other parameters of ventricular function from GBPS or echocardiography. Parameters of the systolic as well as diastolic function were markedly depressed for both left and right ventricles (all p<0.001), and echocardiographic LV systolic diameter was increased in all patients. Phase analsis showed the mean and standard deviation of phase angle(Mph & SDph) of both ventricles to be singificantly greater, and the mean amplitude smaller in DCM patients compared to controls(p<0.01). SDph appeared to be a sensitive parameter(LV 100%, RV 92%), and LV SDph showed significant correlations with other GBPS parmeters such as LV ejection fraction(LVEF) and LV peak ejection rate(LVPER) (r=-0.85 and 0.75, respectively) (all p<0.001), and with LV systolic diameter (r=0.78, p<0.001). Also, LV mean amplitude correlated well with LVEF (r=0.79, p<0.001). Thus, phase analysis of GBPS was able to show and quantify significant asynchronity in contraction of both ventricles in DCM, and these parameters may by useful in evaluating ventricular performance in these patients.