FDG-PET In Differential Diagnosis Research Articles

Evaluating 2-[18F]FDG-PET in differential diagnosis of dementia using a data-driven decision model.

2-[18F]fluoro-2-deoxy-d-glucose positron emission tomography (2-[18F]FDG-PET) has an emerging supportive role in dementia diagnostic as distinctive metabolic patterns are specific for Alzheimer's disease (AD), dementia with Lewy bodies (DLB) and frontotemporal dementia (FTD). Previous studies have demonstrated that a data-driven decision model based on the disease state index (DSI) classifier supports clinicians in the differential diagnosis of dementia by using different combinations of diagnostic tests and biomarkers. Until now, this model has not included 2-[18F]FDG-PET data. The objective of the study was to evaluate 2-[18F]FDG-PET biomarkers combined with commonly used diagnostic tests in the differential diagnosis of dementia using the DSI classifier. We included data from 259 subjects diagnosed with AD, DLB, FTD, vascular dementia (VaD), and subjective cognitive decline from two independent study cohorts. We also evaluated three 2-[18F]FDG-PET biomarkers (anterior vs. posterior index (API-PET), occipital vs. temporal index, and cingulate island sign) to improve the classification accuracy for both FTD and DLB. We found that the addition of 2-[18F]FDG-PET biomarkers to cognitive tests, CSF and MRI biomarkers considerably improved the classification accuracy for all pairwise comparisons of DLB (balanced accuracies: DLB vs. AD from 64% to 77%; DLB vs. FTD from 71% to 92%; and DLB vs. VaD from 71% to 84%). The two 2-[18F]FDG-PET biomarkers, API-PET and occipital vs. temporal index, improved the accuracy for FTD and DLB, especially as compared to AD. Moreover, different combinations of diagnostic tests were valuable to differentiate specific subtypes of dementia. In conclusion, this study demonstrated that the addition of 2-[18F]FDG-PET to commonly used diagnostic tests provided complementary information that may help clinicians in diagnosing patients, particularly for differentiating between patients with FTD, DLB, and AD.

BRAIN FDG-PET IN MILD COGNITIVE IMPAIRMENT: A RETROSPECTIVE LONGITUDINAL STUDY

Brain metabolism alteration represents one of the earlier neuroimaging biomarkers of dementia. This study aimed to verify the predictive role of FDG-PET in differential diagnosis in a cohort of Mild Cognitive Impairment (MCI) patients. Seventy-four MCI patients underwent brain F18-FDG-PET and clinical and neuropsychological follow-up for about two years and a half. Statistical comparisons of FDG-PET scans at baseline were compared between patients who convert to dementia (MCI-D), to Alzheimer’s type Dementia (MCI-AD) or to Fronto-Temporal Dementia (MCI-FTD) and those who remained Stable MCI. Compared with Stable MCI, MCI-D patients at baseline presented hypometabolism in the left superior, middle and inferior temporal gyri and an higher metabolism in the left postcentral gyrus, putamen and in the right insula and claustrum. MCI-AD patients had hypometabolism in the left middle and inferior temporal gyri and a suspected increased metabolism in the bilateral postcentral gyri, in the right precentral gyrus, insula and in the left lentiform nucleus. MCI-FTD showed hypometabolism in the right inferior, middle, superior frontal gyri and inferior, middle and superior temporal gyri. In the prodromal phase, compared with stable MCI, AD was characterized by temporal hypometabolic activity indicating synaptic dysfunction and by higher sub-cortical metabolic activity as possible expression of compensatory mechanisms, whereas FTD by hypometabolic frontal and temporal regions. In MCI patients, FDG-PET is not only an excellent and early diagnostic biomarker, but also a good tool to describe neurobiological correlates of dementia subtypes in time.

Voxel-based classification of FDG PET in dementia using inter-scanner normalization

Statistical mapping of FDG PET brain images has become a common tool in differential diagnosis of patients with dementia. We present a voxel-based classification system of neurodegenerative dementias based on partial least squares (PLS). Such a classifier relies on image databases of normal controls and dementia cases as training data. Variations in PET image characteristics can be expected between databases, for example due to differences in instrumentation, patient preparation, and image reconstruction. This study evaluates (i) the impact of databases from different scanners on classification accuracy and (ii) a method to improve inter-scanner classification. Brain FDG PET databases from three scanners (A, B, C) at two clinical sites were evaluated. Diagnostic categories included normal controls (NC, nA=26, nB=20, nC=24 for each scanner respectively), Alzheimer's disease (AD, nA=44, nB=11, nC=16), and frontotemporal dementia (FTD, nA=13, nB=13, nC=5). Spatially normalized images were classified as NC, AD, or FTD using partial least squares. Supervised learning was employed to determine classifier parameters, whereby available data is sub-divided into training and test sets. Four different database setups were evaluated: (i) "in-scanner": training and test data from the same scanner, (ii) "x-scanner": training and test data from different scanners, (iii) "train other": train on both x-scanners, and (iv) "train all": train on all scanners. In order to moderate the impact of inter-scanner variations on image evaluation, voxel-by-voxel scaling was applied based on "ratio images". Good classification accuracy of on average 94% was achieved for the in-scanner setups. Accuracy deteriorated for setups with mismatched scanners (79-91%). Ratio-image normalization improved all results with mismatched scanners (85-92%). In conclusion, automatic classification of individual FDG PET in differential diagnosis of dementia is feasible. Accuracy can vary with respect to scanner or acquisition characteristics of the training image data. The adopted approach of ratio-image normalization has been demonstrated to effectively moderate these effects.

A Comparison of F-18 FDG PET in Differential Diagnosis of Alzheimer's Disease with Parkinsonism and Dementia with Lewy Bodies Disease

have pointed out haemodynamic changes of the medial temporal lobe in 61.11% of 144 TGA patients examined during the acute phase. A follow-up SPECT showed that the lesions disappeared after 12 months. Conclusions: These observations claim that TGA may be considered a complex epiphenomenon, and the sum of the trigger factors can be responsible for this event. Given the good prognosis and the lack of association with organic abnormalities, we advance the hypothesis that TGA may be related to psychological disturbances causing transient alteration in brain metabolism in memory-relevant structures and, consequently, amnesia.

Amyloid PET in mild cognitive impairment and Alzheimer’s disease with BF-227: comparison to FDG–PET

We recently developed a novel PET tracer, (11)C-labeled 2-(2-[2-dimethylaminothiazol-5-yl]ethenyl)-6-(2-[fluoro]ethoxy)benzoxazole ([(11)C]BF-227), and had success with in vivo detection of amyloid plaques in Alzheimer's disease (AD) brains (Kudo et al. in J Nucl Med 8:553-561, 2007). We applied this tracer to subjects with mild cognitive impairment (MCI) and AD in order to elucidate the status of amyloid plaque deposition in MCI and compared the diagnostic performance of BF-227-PET with that of FDG-PET in AD cases. We studied 12 aged normal (AN) subjects, 15 MCIs and 15 ADs with PET using [(11)C]BF-227. PET images were obtained after administration of BF-227 and the regional standardized uptake value (SUV) and the ratio of regional to cerebellar SUV were calculated as an index of BF-227 binding. AD patients showed increased uptake of [(11)C]BF-227 in the neocortical areas and striatum as well as decreased glucose metabolism in temporoparietal, posterior cingulate and medial temporal areas. MCI subjects showed a significant increase in BF-227 uptake in the neocortical areas similar to AD, and the most significant difference of BF-227 retention was observed in the parietal lobe if its retentions for MCI were compared to those for AD and AN. On the other hand, glucose hypometabolism in MCI was confined to cingulate and medial temporal cortices. Neocortical BF-227 uptake negatively correlated with glucose metabolism. Receiver operating characteristic (ROC) analysis indicated higher specificity and sensitivity with BF-227-PET than those with FDG-PET for differential diagnosis between AD and normal control. We conclude that [(11)C]BF-227-PET has a possibility to be a useful technology for early detection of AD pathology and also even in the MCI stage.

Comparison of early and delayed FDG PET for evaluation of biliary stricture

We assessed whether delayed FDG PET imaging is more useful for the evaluation of biliary stricture in differential diagnosis of malignancy from benign disease. Thirty-seven patients who underwent FDG PET for differential diagnosis of the disease causing biliary stricture were included. FDG PET imaging was performed at 70+/-12 min (early) post FDG injection and repeated 188+/-27 min (delayed) after injection only in the abdominal region. Image analysis was performed with visual interpretation and using a semi-quantitative method if lesion was visible on the PET image. The semi-quantitative analysis using the standardized uptake value (SUV) was determined for both early and delayed images (SUVearly and SUVdelayed, respectively). The tumour-to-normal liver (T/L) ratio was also calculated. The final diagnosis was cholangiocarcinoma in 29 and benign disease in eight patients. In cases of cholangiocarcinoma, visual analysis of FDG PET using the delayed images, improve the diagnosis with one more patient correctly identified. For early and delayed FDG PET, sensitivities were 82.8% and 86.2%, respectively; specificities were 87.5% for both; and accuracies were 83.8% and 86.5%, respectively. Both SUV and T/L ratio derived from delayed images were significantly higher than those derived from early images for cholangiocarcinoma (P<0.0002 and P<0.0001, respectively). FDG PET could be useful for differential diagnosis of malignancy from benign disease in patients with biliary stricture. Especially, the delayed targeted FDG PET imaging can be recommended in those patients when early imaging is negative or equivalent, because of increased lesion uptake and increased lesion to background contrast ratio.

Usefulness of 18F‐fluorodeoxyglucose positron emission tomography in differential diagnosis and staging of cholangiocarcinomas

(18)F-Fluoro-2-deoxy-d-glucose positron emission tomography ((18)FDG-PET) is promising for diagnosis and treatment of various malignancies. The aim of this study was to evaluate the clinical usefulness of (18)FDG-PET in differential diagnosis and staging of cholangiocarcinomas according to the intrahepatic, perihilar and common bile duct lesions and to compare with computerized tomography (CT) scan. From January 2000 to September 2003, 54 patients with suspected cholangiocarcinoma underwent abdominal CT scan and (18)FDG-PET within a 2-week period. The PET images were analyzed visually and semiquantitatively. The overall accuracy of (18)FDG-PET for discriminating malignant diseases of bile duct from benign conditions was slightly higher than that of CT scan (88.9% vs 81.5%). The sensitivity of (18)FDG-PET in perihilar cholangiocarcinoma was lower than the value of intrahepatic and common bile duct cancers (83.3% vs 91.3%, 90.9%); moreover, in cases of perihilar cancer, the sensitivity of (18)FDG-PET was lower than that of CT scans (83.3% vs 91.7%). (18)FDG-PET detected nine distant metastatic lesions not found by other imaging studies and excluded two patients who potentially had resectable condition in other imaging studies from unnecessary laparotomy. The clinical usefulness of (18)FDG-PET in differential diagnosis of bile duct cancers is related to the site of primary disease. Although it is a helpful method for differential diagnosis especially in cases of intrahepatic and common bile duct cancers, (18)FDG-PET can not provide confirmative clues in perihilar cholangiocarcinoma. (18)FDG-PET may hold promise in the detection of hidden distant metastasis and can play an additional role in the evaluation of resectability. (18)FDG-PET can be complementary to CT scan in diagnosing and staging of cholangiocarcinoma.

Usefulness of Functional Image Analysis Using Positron Emission Tomography for the Discrimination between Hypoplastic Myelodysplastic Syndromes and Aplastic Anemia.

Myelodysplastic syndromes (MDS) and aplastic anemia (AA) are classified bone marrow failure syndromes. Their clinical and pathological features partly overlap. It is sometimes difficult to distinguish hypoplastic MDS from AA by using current common diagnostic methods such as bone marrow biopsy and chromosome analysis. Although magnetic resonance image (MRI) is useful for diagnosis of MDS with hypercellular bone marrow, it is difficult to discriminate between hypoplastic MDS and AA using this method because the high intensity patterns on T1-enhanced images are similar in these disorders. Quantitative imaging with fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) has been recognized as a useful examination for discrimination between benign and malignant regions in various conditions. Since the decrease in FDG uptake at the late phase is much slower in a malignant region than in a benign region, dual time point imaging provides more accurate information than does conventional single time point scanning. In this study, we investigated the usefulness of dual time protocol FDG-PET in differential diagnosis of hypoplastic MDS and AA. Seventeen patients (7 with typical MDS (RA), 4 with hypoplastic MDS, 6 with AA) and 30 healthy adults agreed to participate in this study. Bone marrow biopsy, FDG-PET, MRI and CT were carried out. Spine, femur and iliac lesions were detected by their increased FDG uptake at 60 and 120 min after injection of 0.12 mCi/kg of FDG. The mean lesional standardized uptake values (SUVmean) at 60 and 120 min after injection of FDG were determined. While the median SUVmean of normal lumbar regions at 60 min was 1.123 ± 0.219, that of MDS cases was 2.06 (range, 1.62–2.32). At 120 min, the median SUVmean of normal cases was 1.180 ± 0.119, whereas that of MDS cases was 2.44 (range, 2.08–2.98). It is noteworthy that the SUVmean of four hypoplastic MDS cases was also high (ranges: 1.96–2.23 at 60 min and 1.97–2.52 at 120 min), suggesting that bone marrow in hypoplastic MDS has a hyper-metabolic state of glucose like other malignant disorders. We also observed a patchy hot area, which may be a visualization of ineffective hematopoiesis, throughout the spine image of hypoplastic MDS. In contrast, the SUVmeans at both time points of four AA cases were not different from those in normal control cases. These results suggest that functional imaging analysis using an FDG-PET dual time protocol enables discrimination between hypoplastic MDS and AA, in which MR images similar intensities.

副咽頭間隙腫ようにおけるＦＤＧ‐ＰＥＴの有用性

副咽頭間隙腫ようにおけるＦＤＧ‐ＰＥＴの有用性

FDG-PET in differential diagnosis and grading of chondrosarcomas.

The purpose of this work was to investigate the usefulness of PET with [18F]2-deoxy-2-fluoro-D-glucose (FDG) in the differential diagnosis and grading of chondrosarcomas. Four enchondromas, one osteochondroma, and six chondrosarcomas were prospectively studied by FDG-PET. The significance of the standardized uptake value (SUV) was evaluated in comparison with clinical, radiological, and histopathological findings of the tumors. The SUV ranged from 0.7 to 1.3 (mean 0.96+/-0.22) in benign cartilage tumors and from 1.3 to 3.3 (2.23+/-0.80) in chondrosarcomas. This SUV difference between benign and malignant tumors was statistically significant (p = 0.011) in contrast to considerable overlap of clinical and radiological findings. Among chondrosarcomas, the SUV of one Grade I tumor was 1.3; those of four Grade II tumors were 1.3, 1.9, 2.5, and 3.1; and that of one Grade III tumor was 3.3. Our preliminary study showed that FDG-PET could be an objective and quantitative adjunct in the differential diagnosis and grading of chondrosarcomas.

Malignant and Benign Diffuse Pleural Disease: Utility of FDG PET in Differential Diagnosis and Comparison with CT

Malignant and Benign Diffuse Pleural Disease: Utility of FDG PET in Differential Diagnosis and Comparison with CT