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In Japan, the Southampton method for dopamine transporter (DAT) SPECT is widely used to quantitatively evaluate striatal radioactivity. The specific binding ratio (SBR) is the ratio of specific to non-specific binding observed after placing pentagonal striatal voxels of interest (VOIs) as references. Although the method can reduce the partial volume effect, the SBR may fluctuate due to the presence of low-count areas of cerebrospinal fluid (CSF), caused by brain atrophy, in the striatal VOIs. We examined the effect of the exclusion of low-count VOIs on SBR measurement. We retrospectively reviewed DAT imaging of 36 patients with parkinsonian syndromes performed after injection of 123I-FP-CIT. SPECT data were reconstructed using three conditions. We defined the CSF area in each SPECT image after segmenting the brain tissues. A merged image of gray and white matter images was constructed from each patient’s magnetic resonance imaging (MRI) to create an idealized brain image that excluded the CSF fraction (MRI-mask method). We calculated the SBR and asymmetric index (AI) in the MRI-mask method for each reconstruction condition. We then calculated the mean and standard deviation (SD) of voxel RI counts in the reference VOI without the striatal VOIs in each image, and determined the SBR by excluding the low-count pixels (threshold method) using five thresholds: mean-0.0SD, mean-0.5SD, mean-1.0SD, mean-1.5SD, and mean-2.0SD. We also calculated the AIs from the SBRs measured using the threshold method. We examined the correlation among the SBRs of the threshold method, between the uncorrected SBRs and the SBRs of the MRI-mask method, and between the uncorrected AIs and the AIs of the MRI-mask method. The intraclass correlation coefficient indicated an extremely high correlation among the SBRs and among the AIs of the MRI-mask and threshold methods at thresholds between mean-2.0D and mean-1.0SD, regardless of the reconstruction correction. The differences among the SBRs and the AIs of the two methods were smallest at thresholds between man-2.0SD and mean-1.0SD. The SBR calculated using the threshold method was highly correlated with the MRI–SBR. These results suggest that the CSF correction of the threshold method is effective for the calculation of idealized SBR and AI values.

The aims of this study were to evaluate the possibility of using (11)C-methionine ((11)C-MET) and (11)C-4'-thiothymidine ((11)C-4DST) whole-body PET/CT for the imaging of amino acid metabolism and DNA synthesis, respectively, when searching for bone marrow involvement in patients with multiple myeloma (MM) and to compare these findings with those for (18)F-FDG PET/CT and aspiration cytology.A total of 64 patients with MM, solitary plasmacytoma, monoclonal gammopathy of undetermined significance, or an unspecified diagnosis were prospectively enrolled. All the patients underwent three whole-body PET/CT examinations within a period of 1 week. First, the tracer accumulation was visually evaluated as positive, equivocal, or negative for 55 focal lytic lesions visualized using CT in 24 patients. Second, the percentages of marrow plasma cells as calculated using a bone marrow aspiration smear and tracer accumulation were evaluated in the posterior iliac crests of 36 patients.Among the 55 lytic lesions, the (11)C-MET and (11)C-4DST findings tended to reveal more positive findings than the (18)F-FDG findings. Based on the standard criteria for the diagnosis of active myeloma using the percentage of marrow plasma cells, significant differences were found between the (18)F-FDG and (11)C-MET findings and between the (18)F-FDG and (11)C-4DST findings, but no significant difference was observed between the (11)C-MET and (11)C-4DST findings.The addition of (11)C-MET and (11)C-4DST to (18)F-FDG when performing PET/CT enabled clearer evaluations of equivocal lesions. Based on cytological diagnostic criteria, (11)C-MET and (11)C-4DST were more sensitive than (18)F-FDG for the detection of active lesions. (11)C-MET and (11)C-4DST were more useful than (18)F-FDG for the detection of active lesions, especially during the early stage of disease.

Purpose To characterize the heterogeneity of metastatic neuroendocrine tumor (NET) lesions, we compared the [18F]-fluorodeoxyglucose (FDG) uptake and the 111In-pentetreotide (SRS) uptake for somatostatin receptor scintigraphy using the CT-based fusion imaging techniques of PET/CT and SPECT/CT. Methods Fifteen consecutive patients with NET lesions were examined using both FDG-PET/CT and SRS SPECT/CT prospectively. A total of 45 metastatic NET lesions were evaluated for FDG uptake according to the standardized uptake value (SUV) and for SRS uptake according to the tumor-to-muscle count ratio (T/M ratio); these values were then compared according to the grade of NET (G), also compared to the tumor volume. Results Both the SRS uptake and FDG uptake showed no significant correlation to the tumor volume, and suggested no significant artifacts in these data. The T/M ratio for the SRS uptake ranged from 192.7 to 1.9 and exhibited very wide range of distribution. The SUV for the FDG uptake ranged from 13.8 to 0.77 and exhibited narrow range of distribution. The uptake of the two tracers in individual lesions showed an inverse correlation. The G1 + 2 lesions had a higher SRS uptake than the G3 lesions, but the difference was not significant because of the large variation (40.65 ± 48.03, n = 39 vs. 8.66 ± 13.13, n = 6). However, the G1 + 2 lesions had a significantly lower FDG uptake than the G3 lesions (3.52 ± 1.84, n = 39 vs. 10.82 ± 4.50, n = 6). The tracer uptakes varied largely not only in an inter-subject manner, but also in an intra-subject manner. Conclusion An inverse correlation between SRS uptake and FDG uptake in the metastatic NET lesions observed in this study may be consistent with the opposing ideas of differentiation and proliferation in oncology. The large variations in SRS and FDG uptake by metastatic NET lesions suggest the biological heterogeneity of advanced NET. These results support the idea that combination therapy targeting both receptor-positive cells and proliferating cells may be beneficial from a functional imaging perspective.

Cardiac FDG uptake is known to show a variety of patterns under clinical fasting conditions. We hypothesized that focal FDG uptake in the heart (FUH) represents a sign of cardiac disease risk, especially in coronary artery disease (CAD).The aim of this study was to clarify the relationship between FUH and cardiac disease. Cases showing FUH were selected based on comments in diagnostic reports or identification on retrospective review. Quantitative analysis was performed using maximum standardized uptake value (SUVmax), with regions of interest drawn over focal uptake areas in the heart as confirmed by PET/CT and in lateral side of the same slice showing focal FDG uptake. For the 20 patients (11 men, 9 women) with confirmed FUH, coronary artery stenosis or history of treatment for coronary disease was present in 11 patients (55.0 %), and 2 patients showed apical hypertrophy. Mean SUVmax of FUH did not differ significantly between patients with confirmed cardiac disease and those with no evidence of cardiac disease (P = 0.78). FUH suggests a high likelihood of CAD in patients without myocardial symptoms. Cardiac screening or a check of the history of cardiac disease is thus worth considering when FUH is seen incidentally on FDG-PET/CT.

The aim of this study was to evaluate the interpretations of incidental colonic 18F-FDG uptake made by 10 experienced readers and to more clearly identify the pattern of suspicious colonic FDG uptake. The potential contributions of delayed FDG-PET scanning and of immune fecal occult blood testing (FOBT) in making a diagnosis were also analyzed.Visual interpretations by 10 readers were made for 147 FDG uptake sites from 126 PET scans (cancer, 38 sites; adenoma, 43 sites; and no abnormality, 66 sites) with colonic FDG uptake. Assessments for the early FDG-PET images were (1) FDG uptake pattern, (2) FDG uptake degree, and (3) likelihood of malignancy. For the delayed images, the assessments were (1) change in the FDG uptake position, (2) change in FDG uptake degree, and (3) likelihood of malignancy. The results of FOBT were analyzed independently of the visual interpretations.Interobserver agreement (κ) was 0.501 for assessing FDG uptake patterns, while agreement on assessing changes in uptake degree and changes in uptake position between early and delayed imaging were low (κ = 0.213-0.229). Logistic regression analysis indicated that 'FDG uptake patterns' and 'FDG uptake degree' were significantly related to decide on the suspicion of malignancy (p0.001) and the final result (p0.001). "Small localized" and "large irregular localized" types had a high probability of a lesion regardless of either (1) FDG uptake degree or (2) variation in the uptake between the early and the delayed image. The delayed image decreased false-positive cases for some FDG uptake patterns, but it had little impact on distinguishing clearly between "cancer or adenoma" and "normal". The addition of FOBT had little impact on the diagnosis.There was highest agreement among readers with respect to the recognition of specified colonic FDG uptake patterns, and this pattern recognition had the most influence on the diagnosis. "Small localized" and "large irregular localized" types had a high probability of a lesion. The addition of delayed imaging and of FOBT results to the early imaging did not have much impact on the diagnosis.

Vocal cord palsy (VCP) is a potential cause of hoarseness that results in decreasing mobility of the vocal cord. VCP can arise from a variety of causes; so, systematic screening is warranted for the management of patients with VCP. Asymmetrical fluorodeoxyglucose (FDG) uptake in vocal cords is a well-known feature in patients with VCP, but no detailed analysis has been performed. This study aimed at reevaluating the 18F-FDG positron emission tomography/computed tomography (PET/CT) for patients with VCP. We retrospectively surveyed the results of FDG-PET/CT for 59 patients with VCP, compared to laryngoscopic findings. Quantitative analysis was performed using maximum standardized uptake value (SUVmax), and regions of interest were drawn over bilateral vocal cords as confirmed from the CT portion of PET/CT. Patients were divided into 3 groups: Group 1 (n = 14), in which VCP was caused by the lesion of the laryngeal area; Group 2 (n = 40), in which VCP was caused by the lesion on the root of the recurrent laryngeal nerve; and Group 3 (n = 5), in which VCP was caused by the lesion from the vagal center to the proximal vagus nerve. For Group 1, higher FDG uptake in the paralyzed vocal cord was seen in 86 % of patients (mean SUVmax 8.1 ± 5.3 vs. 2.3 ± 0.4, paralyzed vs. non-paralyzed, respectively; P

Tumors producing granulocyte colony stimulating factor (G-CSF), malignant lung tumors in most cases, are rare, and patients present with abnormal elevations of the white blood cell (WBC) count in the absence of any infectious disease. We present the (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG-PET/CT) imaging findings of two cases of G-CSF-producing tumor. PET-CT showed abnormally high uptake of (18)F-FDG not only by the tumor itself but also diffusely throughout the bone marrow. Following resection of the tumor, the blood G-CSF level as well as the WBC count dropped down to normal range in both cases. Histopathological examination of the resected tumor specimens revealed the presence of an enormous number of inflammatory cells within the tumors and positive immunostaining of the tumor cells for G-CSF. The (18)F-FDG-PET/CT findings could be explained by the elevated bone marrow metabolism associated with the excessively active production of granulocytes under G-CSF stimulation, and the (18)F-FDG uptake by the inflammatory cells also contributing to the total tumor uptake of (18)F-FDG. These characteristic imaging findings are expected to be useful for the diagnosis of G-CSF-producing tumors.

We present a case in which an amyloid lung nodule was diagnosed preoperatively by amyloid scintigraphy (99m)Tc-aprotinin. A 65-year-old man complained of marked weight loss (9 kg) over a period of 6 months. An abnormal shadow in the middle field of the right lung was detected on chest X-ray, corresponding to a 16-mm nodule in the right middle lobe on thoracic computed tomography (CT). Total protein and immunoglobulin G levels were elevated to 8.3 and 2245 mg/dl, respectively, but other blood tests including several tumor marker levels and Cryptococcus antibodies were all within normal range. Fluorodeoxyglucose positron emission tomography showed no uptake by the lung nodule, so lung amyloidosis was considered as differential diagnosis. To avoid risk of bleeding on bronchoscopy, noninvasive amyloid scintigraphy using (99m)Tc-aprotinin was first performed. A nodular, abnormal accumulation was observed in the right middle lung lobe. Diagnostic imaging strongly suggested amyloidosis, so video-assisted thoracic surgery was performed rather than bronchoscopy. Pathological samples showed positive staining with Congo red, and A-λ amyloidosis was diagnosed on the basis of immunostaining. Scintigraphy using (99m)Tc-aprotinin offers a useful, noninvasive method for assessing lung amyloidosis.

To evaluate the clinical value of 2-[(18)F]fluoro-2-deoxy-D: -glucose positron emission tomography (FDG-PET) for the diagnosis of fever of unknown origin (FUO), we performed a Japanese multi-center retrospective survey.A total of 81 consecutive patients with FUO who underwent FDG-PET at 6 institutions between July 2006 and December 2007 were retrospectively evaluated. FDG uptake was visually evaluated using a 4-grade scale. The efficacy of FDG-PET for the evaluation of FUO, the provision of additional diagnostic information, the clinical impact on therapeutic decisions (4-grade scale), and the diagnostic performance compared with the final diagnosis were evaluated.The diagnostic results were analyzed according to 4 groups of final diagnoses: infection, arthritis/vasculitis/autoimmune/collagen disease (A/V), tumor/granuloma (T/G), and other/unknown (O/U). Sensitivity was highest in T/G, followed by infection, A/V and O/U [100%(7/7), 89%(24/27), 65%(11/17), 0%(0/1) respectively]. Clinical impact and mean FDG score showed the same tendency. Additional information was highest in infection followed by T/G, A/V, and O/U [76%(22/29), 75%(6/8), 43%(9/21), 23%(5/22), respectively]. The O/U group showed a high specificity (84%, 16/19) and accurately excluded active focal inflammatory diseases and malignancy. The use of steroids for the treatment of fever seemed to mask the lesions and modified the results, especially in the A/V group (4 false negatives in 8 steroid users out of 21 A/V patients). The prevalence of each disease in each hospital significantly affected the effectiveness of FDG-PET for the diagnosis of FUO. The mean FDG uptake score and additional information (70%, 31/44 vs. 30%, 11/37, respectively) in national hospital (NH) was significantly higher than in university hospitals (UH). A Grade 3 clinical impact, in which the FDG PET results changed the clinical decision, was seen in 50% (22/44) of the patients in the NH group and 13.5% (5/37) of the patients in the UH group. The sensitivity (91%, 30/33; 63%, 12/19) and specificity (60%, 6/10; 86%, 12/14) of the results in the NH and UH groups differed. The total sensitivity was 81% (42/52), specificity was 75% (18/24). The NH group included a large number of cases with infectious diseases (50%, 23/44), while the UH group included a large number of A/V cases (38%, 14/37) and O/U cases (41%, 15/37).FDG-PET for the diagnosis of FUO provided additional diagnostic information and had a high clinical impact, especially among patients with infectious diseases. It was also helpful in cases with unknown or other miscellaneous diseases by allowing the exclusion of focally active diseases. The prevalence of diseases in hospitals significantly affected the effectiveness of FDG-PET for the diagnosis of FUO. FDG-PET is a useful examination providing various degrees of clinical impact for the management of FUO, depending on the characteristics of the patient and the hospital.

Pyothorax-associated lymphoma (PAL) is a rare form of lymphoma and its management on 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) combined computed tomography (CT) has not been well reported. The purpose of this study was to evaluate the usefulness of FDG PET/CT in patients with PAL. Twenty-four PET/CT images in seven patients (5 men and 2 women) with PAL were studied retrospectively. Five of the 24 PET/CT scans were done for diagnosis and staging, 6 for restaging, 3 for follow-up, and 10 to evaluate the treatment response. PET/CT scan interpretations were performed visually and using the maximum standardized uptake values (SUVmax). Additionally, the efficacy of the enhanced CT findings in pre- and post-treatments was described. Six of the 7 patients with PAL received radiotherapy, and the efficacy of treatment was observed in their lesions. The percentage decrease of SUVmax in PAL was useful in providing complementary information. Enhanced CT findings showed decreasing enhancement of PAL after treatment; however, in five cases, residual masses were confirmed after treatment. FDG PET/CT may be an ideal modality for reducing the false-positive interpretation of residual masses occurring after treatment for PAL. The SUVmax provides complementary information for the management of PAL.

A 58-year-old woman with dysphagia and hoarseness underwent 18F-FDG PET/CT to detect the original lesion and disease spread. Bilateral cervical lymphadenopathy and abnormal FDG uptakes in the right tonsil and pharyngeal wall were demonstrated. CT and MRI confirmed the bilateral cervical lymphadenopathy and mucosal thickening in the pharyngeal wall. On the basis of these findings, biopsy sites were selected. Pharyngeal tuberculosis was diagnosed based on culture of the biopsy specimens. 18F-FDG PET/CT contributed to clinical management in this case by detecting tuberculous lesions and showing the extent of these lesions in one examination.

We present two cases of tuberculous pericarditis that were diagnosed using 18F-fluorodeoxyglycose (18F-FDG) positron emission tomography (PET). Here, we highlight the value of 18F-FDG-PET for demonstrating tuberculous pericardial involvement as well as disease dissemination and activity. The patients received antitubercular treatment, and their symptoms and findings resolved accordingly.

Fluorodeoxyglucose (FDG) uptake in joint lesions in patients with rheumatoid arthritis (RA) reportedly represents the degree of synovial inflammation. Most previous studies have focused on small joints, and the application of whole-body positron emission tomography (PET) combined with computed tomography (CT) (PET/CT) for the evaluation of inflammatory activity in large joints has not been well studied.Eighteen patients with RA underwent FDG-PET/CT. FDG uptake in the knee, hip, carpal, wrist, elbow, shoulder, and atlanto-axial joint (total of 13 joints) and in the axillary lymph nodes was evaluated by calculating the maximum standardized uptake value (SUV(max)) and the visual uptake scores as follows: 0, no uptake; 1, slight uptake; 2, moderate uptake (same as in liver); 3, higher than in liver; 4, highest uptake. The number of painful/swollen joints, the white blood cell (WBC) count, and the C-reactive protein (CRP) level were also evaluated.Whole-body FDG-PET/CT delineated large-joint lesions in patients with RA, and the metabolic activity of inflammation was accurately overlaid on the joint anatomy. The total FDG score for all 13 joints was significantly correlated with the CRP level (r = 0.653, p0.01, n = 18). The total SUV(max) and the CRP level were weakly, but not significantly, correlated (r = 0.377, p0.05). The WBC count was not correlated with any other parameter. The mean number of joints per patient with an FDG uptake score of 2 or more was significantly larger than the mean number of painful/swollen joints (6.2 +/- 3.3 vs. 3.1 +/- 2.7, n = 18, p0.01) and both parameters were strongly correlated (r = 0.588, p0.01, n = 18). Also, FDG uptake score and SUV of painful/swollen joints were significantly higher than these of not painful/swollen joints. FDG uptake was significantly different from patients of remission and patients of active arthritis. Uptake in the atlanto-axial joint was observed in five (mostly asymptomatic) patients (5/18, 28%), and the uptake score was significantly correlated with the total FDG score (r = 0.669, p0.01, n = 18). The axillary lymph nodes score was correlated with the arm joints score.FDG-PET/CT represents the inflammatory activity in large joints in patients with RA accurately and sensitively and may be helpful for early evaluations of the extent of RA throughout the whole body including high risk lesion of atlanto-axial joint. Furthermore, the visual FDG uptake score may be useful for evaluating arthritis in large joints.

The purpose of this study was to evaluate the usefulness of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in differentiating pulmonary artery sarcoma from pulmonary embolism.We evaluated three patients with pulmonary artery sarcoma and 10 patients with proximal pulmonary embolism (6 men and 7 women, ranging in age from 35 to 94 years). All the patients had evidence of perfusion defects in their proximal pulmonary arteries on contrast-enhanced computed tomography (CT) scans performed prior to PET/CT. The maximum standardized uptake value (SUV(max)) of FDG uptake in all the lesions was measured using PET/CT. The location of lesions, background uptake or thrombi in the legs were evaluated in both groups as basic characteristics.The mean SUV(max) of the pulmonary artery sarcomas (7.63 +/- 2.21, n = 3) and the pulmonary embolisms (2.31 +/- 0.41, n = 10) were significantly different (P0.05). The mean times between the initial contrast-enhanced CT scan and PET/CT scan were similar in both groups (P = 0.7804). The differences in the locations in lesions between the three groups (right, left and bilateral) or background uptakes were not significant.FDG PET/CT could distinguish pulmonary artery sarcoma from pulmonary embolism based on the SUV(max) value.

Objective Wegener’s granulomatosis (WG) is a relatively rare disease characterized by granulomatous necrotizing vasculitis that primarily involves small- and medium-sized vessels. Systemic findings observed on 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) have not been well reported. The purpose of this study was to evaluate the FDG PET/CT imaging in the diagnosis and follow-up of patients with WG. Materials and methods Thirteen FDG PET/CT images obtained for 8 patients (2 men and 6 women) with WG were retrospectively analyzed. Of these, 6 were performed for diagnosis, 2 for restaging and follow-up, and 5 for assessment of treatment efficacy. Maximum standardized uptake values (max SUVs) and visual analyses were used to interpret the FDG PET/CT images. In addition, nonenhanced CT findings obtained during FDG PET/CT were described. Results WG lesions of the upper respiratory tract and lung were more clearly detected by FDG PET/CT fusion imaging than by nonenhanced CT alone, and all of the active lesions showed decreased FDG uptake after treatment. In addition, FDG PET/CT can provide complementary information to indicate biopsy site based on FDG uptakes. Conclusions FDG PET/CT is a feasible modality for evaluating lesion activities, therapeutic monitoring, and follow-up of WG. Furthermore, biopsy sites of WG lesions may be determined by FDG PET/CT.