The physiological uptake pattern of (18)F-FDG in the left ventricular myocardium of patients without heart disease.

PURPOSE: The purpose of this study was to evaluate the physiological uptake pattern of (18)F-FDG in the left ventricular myocardium of patients under preparation for tumor FDG-PET. PATIENTS AND METHODS: We enrolled 188 patients without cardiac disease. The accumulation patterns were classified as either 'none', 'diffuse', 'focal' or 'focal on diffuse'. When a focal uptake was only observed on the basal wall, then the patterns were classified as having either a 'ring', 'over half' or 'spot' uptake. RESULTS: The frequencies of the myocardial FDG uptake patterns were as follows: none, n=52 (27.7%); diffuse, n=63 (33.5%); focal on diffuse, n=40 (21.3%) and focal, n=33 (17.6%). The age, blood glucose level, weight and dose of FDG did not differ significantly for each pattern. The focal and focal on diffuse patterns were seen in 73 patients, and 65 patients had a focal uptake only on the basal wall; ring uptake in 29 patients, over half in 20 and spot uptake in 16 patients. CONCLUSIONS: The physiological myocardial uptake showed several patterns. Focal uptake was often seen in patients with cardiac disease, but it did not always indicate an abnormal finding when the accumulation was only on the basal wall.

Comparing the performance of visual estimation and standard uptake value of F-18 fluorodeoxyglucose positron emission tomography/computed tomography for detecting malignancy in pancreatic tumors other than invasive ductal carcinoma.

INTRODUCTION: The utility of FDG PET/CT for the detection and evaluation of invasive ductal carcinoma has been widely reported, but a few studies have assessed the utility of FDG PET/CT to detect malignancy in a variety of pancreatic lesions other than invasive ductal carcinoma. PURPOSE: To compare the diagnostic performance of visual estimation with the semi-quantitative scores of FDG PET/CT for detecting malignancy in a variety of pancreatic lesions other than invasive ductal carcinoma. MATERIAL AND METHODS: Images of pathologically proven pancreatic lesions from 32 patients were retrospectively evaluated: 14 benign lesions, 7 borderline (low malignant) lesions, and 11 malignant lesions. The average scores from visual estimation by the two observers were compared to two semi-quantitative analyses of FDG uptake in the lesions, namely the maximum standardized uptake value (SUVmax) and mean standardized uptake value (SUVmean). RESULTS: Visual analysis value, SUVmax and SUVmean were 0.33 ± 0.21, 1.8 ± 0.7 and 1.5 ± 0.7 for the benign lesions, 0.70 ± 0.28, 5.0 ± 2.6 and 3.1±1.7 for the borderline lesions, and 0.73 ± 0.18, 4.7 ± 2.5 and 3.2 ± 1.6 for the malignant lesions, respectively. Receiver operating characteristic analysis revealed the areas under the curves for detecting non-benign (malignant or borderline) lesions through visual analysis, SUVmax, and SUVmean were 0.914, 0.954, and 0.875, respectively. CONCLUSION: For a variety of pancreatic lesions other than invasive ductal carcinoma, visual analysis and semi-quantitative analyses all showed strong diagnostic performance. However, semi-quantitative analysis with SUVmax proved to be the most effective method for detecting non-benign pancreatic lesions.

Correlations between F-18 FDG PET/CT and pathological findings in soft tissue lesions.

OBJECTIVE: To evaluate the correlations between F-18 FDG uptake imaged with PET/CT and pathological findings in soft tissue lesions. METHODS: Fifty-four soft tissue lesions in 47 patients were evaluated. The correlations between the degree of FDG uptake, pathological type and grade, and MRI signal intensity and/or enhancement pattern were evaluated. Tumor FDG uptake was quantified by the maximum standardized uptake value (SUVmax). RESULTS: Thirty-one lesions were malignant and twenty-three lesions were benign. The difference between SUVmax in the malignant and benign groups was statistically significant (p<0.001). Malignant myxoid lesions and well differentiated liposarcoma showed low FDG uptake. Benign neurogenic lesions showed low FDG uptake while malignant neurogenic tumors showed high FDG uptake, and the difference between SUVmax in the benign and malignant lesions was statistically significant (p<0.001). In a neurofibromatosis type-1 patient who had multiple neurogenic tumors, FDG-PET/CT could distinguish malignant peripheral nerve sheath tumors from other benign lesions with similar MRI findings. CONCLUSIONS: FDG-PET/CT is useful for differentiating malignant from benign soft tissue lesions, but malignant soft tissue lesions may show various patterns on FDG-PET, and MRI may be helpful for a differential diagnosis.

(18)F-2-fluoro-2-deoxyglucose uptake in or adjacent to blood vessel walls.

Incidental (18)F-2-fluoro-2-deoxyglucose (FDG) uptake in blood vessel walls is sometimes demonstrated during routine oncologic imaging with positron emission tomography/computed tomography (PET/CT). FDG uptake in vessel walls can also be seen under some non-physiological conditions such as vasculitis and arteriosclerosis. Radiologists need to be aware of the diseases which can exhibit FDG uptake in the vessel wall for proper interpretation.

Visual and semi-quantitative assessment of brain tumors using (201)Tl-SPECT.

OBJECTIVE: To evaluate the usefulness of (201)Tl-SPECT in differentiating benign from malignant brain tumors. METHODS AND MATERIALS: Eighty-eight patients (44 males and 44 females) with 58 high-grade (WHO grade III-IV) and 30 low-grade (WHO grade I-II) tumors were evaluated with (201)Tl-SPECT. (1) Visual assessment was performed by board-certificated radiologists using (201)Tl-SPECT. Tumors were classified in two groups (Tl-positive and Tl-negative) and scored using the five grade evaluation system. Receiver operating characteristic (ROC) analysis was performed in the Tl-positive group. (2) Semi-quantitative assessment involved measurement of early and delayed (201)Tl uptake, and the retention index (RI) was applied as follows: RI=delayed uptake ratio/early uptake ratio. Three combinations of RI using mean and maximum values of the region of interest were calculated. RESULTS: (1) Seventy-four Tl-positive and 14 Tl-negative tumors. The area under the ROC curve (AUC) estimated by three radiologists exceeded a value of 0.7. The value was greater when estimated by the more experienced radiologist. (2) In all RIs, the difference of RI between high-grade tumors and low-grade tumors was statistically significant. CONCLUSION: A visual and semi-quantitative assessment using (201)Tl-SPECT was found to be useful for differentiating benign from malignant brain tumors.

Usefulness of transcatheter arterial embolization prior to excision of hypervascular musculoskeletal tumors.

The objective of this study was to evaluate the usefulness of transcatheter arterial embolization prior to surgical excision of musculoskeletal tumors. We reviewed the records of nine patients (3 females and 6 males) who received arterial embolization prior to excision of musculoskeletal tumors in our hospital from December 2009 to April 2010. We evaluated tumor region, size, histopathology, feeding artery, embolic material, and blood loss during surgery. We compared the actual amount of intraoperative bleeding with arterial embolization to estimated amounts of bleeding without embolization predicted by three orthopedic surgeons. Arterial embolization was performed on the same day or within 5 days before surgery. Operations were performed as planned in all patients without serious complications. The amount of intraoperative bleeding was 35-4200 mL and there was significantly less bleeding with arterial embolization compared with the estimated amounts (p<0.01). Our results show that arterial embolization prior to resection of hypervascular musculoskeletal tumors reduces the amount of bleeding during surgery and contributes to patient safety.