Kazuya Shizukuishi

Prostate cancer: a comparative study of 11C-choline PET and MR imaging combined with proton MR spectroscopy.

PurposeProstate cancer is difficult to visualise in its early stages using current imaging technology. The present study aimed to clarify the utility of 11C-choline PET for localising and evaluating cancer lesions in patients with prostate cancer by conducting a prospective comparison with magnetic resonance (MR) imaging combined with proton MR spectroscopy.MethodsPET and MR imaging combined with proton MR spectroscopy were performed in 20 patients with prostate cancer. Correlations among the metabolite ratio of choline + creatine to citrate (Cho+Cr/Ci) on MR spectroscopy, serum PSA and maximum standardised uptake value (SUVmax) of 11C-choline were assessed. The location of the primary lesion was assessed by the site of SUVmax and the laterality of the highest Cho+Cr/Ci ratio and confirmed by examination of surgical pathology specimens (n=16).ResultsPET exhibited a diagnostic sensitivity of 100% (20/20) for primary lesions, while the sensitivities of MR imaging and MR spectroscopy were 60% (12/20) and 65% (13/20), respectively. Weak linear correlations were observed between SUVmax and serum PSA (r=0.52, p<0.05), and between SUVmax and Cho+Cr/Ci ratio (r=0.49, p<0.05). Regarding the localisation of main primary lesions, PET results agreed with pathological findings in 13 patients (81%) (κ=0.59), while MR spectroscopy results were in accordance with pathological findings in eight patients (50%) (κ=0.11).ConclusionThis preliminary study suggests that 11C-choline PET may provide more accurate information regarding the localisation of main primary prostate cancer lesions than MR imaging/MR spectroscopy. A further clinical study of 11C-choline PET in a large number of patients suspected of prostate cancer will be necessary to determine the clinical utility of 11C-choline PET in patients who clinically require biopsy.

The Roles of PET and PET/CT in the Diagnosis and Management of Prostate Cancer

2-18F-fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET) imaging in prostate cancer is challenging because glucose utilization in well-differentiated prostate cancer is often lower than in other tumor types. Nonetheless, FDG-PET has a high positive predictive value for untreated metastases in viscera, but not lymph nodes. A positive FDG-PET can provide useful information to aid the clinician’s decision on future management in selected patients who have low prostate-specific antigen levels and visceral changes as a result of metastases. On the other hand, FDG-PET is limited in the identification of prostate tumors, as normal urinary excretion of radioisotope can mask pathological uptake. Moreover, there is an overlap in the degree of uptake between prostate cancer, benign prostatic hyperplasia and inflammation. The tracer choice is also important. 11C-choline has the advantage of reduced urinary excretion, and thus 11C-choline PET may provide more accurate information on the localization of main primary prostate cancer lesions than MRI or MR spectroscopy. 11C-choline PET is sensitive and accurate in the preoperative staging of pelvic lymph nodes in prostate cancer. A few studies are available but there were no PET or PET/CT studies with a large number of patients for tissue confirmation of prostate cancer; further investigations are required.

A meta-analysis of 18F-Fluoride positron emission tomography for assessment of metastatic bone tumor

PurposeThe aim of this study was to assess the diagnostic performance of 18F-Fluoride positron emission tomography (PET) or positron emission tomography/computed tomography (PET/CT) compared with bone scintigraphy (BS) planar or BS planar and single photon emission computed tomography (SPECT) in evaluating patients with metastatic bone tumor.Materials and methodsWe performed a meta-analysis of all available studies addressing the diagnostic accuracy of 18F-Fluoride PET, 18F-Fluoride PET/CT, BS planar, and BS planar and SPECT for detecting the metastatic bone tumor. We determined sensitivities and specificities across studies, calculated positive and negative likelihood ratios, and drew summary receiver operating characteristic curves using hierarchical regression models. We also compared the effective dose and cost-effectiveness estimated by data from the enrolled studies between 18F-Fluoride PET or PET/CT and BS planar or BS planar and SPECT.ResultsWhen comparing all studies with data on 18F-Fluoride PET or PET/CT, sensitivity and specificity were 96.2% [95% confidence interval (CI) 93.5–98.9%] and 98.5% (95% CI 97.0–100%), respectively, on a patient basis and 96.9% (95% CI 95.9–98.0%) and 98.0% (95% CI 97.1–98.9%), respectively, on a lesion basis. The Az values of 18F-Fluoride PET or PET/CT were 0.986 for the patient basis and 0.905 for the lesion basis, whereas those of BS or BS and SPECT were 0.866 for the patient basis and 0.854 for the lesion basis. However, the estimated effective dose and average cost-effective ratio were poorer for 18F-Fluoride PET or PET/CT than those of BS planar or BS planar and SPECT.Conclusion18F-Fluoride PET or PET/CT has excellent diagnostic performance for the detection of metastatic bone tumor, but the estimated effective dose and average cost-effective ratio are at a disadvantage compared with BS planar or BS planar and SPECT.

Scoring analysis of salivary gland scintigraphy in patients with Sjögren's syndrome.

The purpose of the present study was to evaluate the validity of a scoring system based on excretion rate of salivary gland scintigraphy in patients with Sjögren’s syndrome (SjS). Total scintigraphic scores were compared with the results of the Saxon test. One hundred and twenty-four subjects who were clinically diagnosed with SjS and 11 normal ones underwent salivary gland scintigraphy and the Saxon test. In salivary gland scintigraphy, the difference between maximum and minimum counts after stimulation using vitamin C divided by maximum counts was defined as the excretion rate. We then defined a scoring system with 4 grades: severe dysfunction = 3 (excretion rate < 25%), moderate dysfunction = 2 (25% ≤ excretion rate < 40%), mild dysfunction = 1 (40% ≤ excretion rate < 50%) and normal function = 0 (50% ≤ excretion rate). The summation of the total scintigraphic score (0–12) of all 4 salivary glands was used as a semi-quantitative index indicating total salivary gland function, and total scintigraphic scores were compared with the results of the Saxon test. A significant inverse linear correlation (R2 = 0.95) was observed between total scintigraphic scores and mean values of the Saxon test within a range of abnormal scintigraphic scores (≥ 4). The scoring system developed in the present study is a clinically available, objective, and reproducible method for evaluation of salivary gland function in patients with SjS.

Evaluation of Response to Multikinase Inhibitor in Metastatic Renal Cell Carcinoma by Fdg Pet/contrast-enhanced Ct

Purpose: Multikinase inhibitor (MKI) is a promising drug for treatment of metastatic renal cell carcinoma (mRCC). We explained the usefulness of [18F]-2-fluoro-2-deoxyglucose positron emission tomography/contrast-enhanced computed tomography (FDG PET/CECT) for mRCC in evaluating the early response to MKI and in predicting progression-free survival (PFS). Methods: Patients who planned MKI treatment for mRCC were included in this prospective study. FDG PET/CECT was performed before MKI treatment and after one cycle of MKI treatment. Evaluation of the response to MKI was assessed by PET according to the European Organization for Research and Treatment of Cancer, by CT according to the Response Evaluation Criteria in Solid Tumors and appearance of central hypoattenuation (CHA). Results: Twelve patients were enrolled in the study. Equality of response evaluation between PET and CT was in 8 patients (partial response [PR]: 1, stable disease [SD]: 6, progressive disease [PD]: 1). Among the other 4 patients, PET showed 2 patients with PR and 2 patients with PD, in contrast to the CT finding of SD in all 4 patients. PFS according to PET response showed a statistically significant difference between PR and SD (P < 0.05) and between PR and PD (P < 0.05), but not between PR and SD (P = 0.083). Positive CHA in metastatic lesions after MKI treatment was confirmed in 8 patients. PFS with positive CHA was 233.8 days, while that without CHA was 75.0 days (P < 0.05). Conclusion: FDG PET/CECT shows potential for evaluating early treatment response to MKI in mRCC and for predicting PFS.

F-18 FDG uptake patterns and disease activity of collagen vascular diseases-associated arthritis.

Purpose: The purpose of the present study was to investigate F-18 FDG uptake patterns, and to see whether joint F-18 FDG uptake reflected disease activity in patients with collagen vascular diseases (CVD)-associated arthritis. Materials and Methods: A total of 72 patients with CVD-associated arthritis and 30 control subjects who underwent F-18 FDG PET or PET/CT were retrospectively investigated. PET images of 12 major joints, 7 minor joints, and extra-articular accumulation were assessed. We investigated F-18 FDG uptake patterns and the relationships between the degree of F-18 FDG uptake and distribution, clinical symptoms, and laboratory test results. Results: Remitting seronegative symmetric synovitis with pitting edema syndrome, mixed connective tissue disease, rheumatoid arthritis, and systemic sclerosis tended to show strong and multiple joint F-18 FDG uptake. F-18 FDG uptake was found in bone marrow (86%) and/or spleen (57%) in 7 patients with adult-onset Still disease. The maximum standardized uptake value (SUVmax) correlated with the counts of erythrocyte sedimentation rate, matrix metalloproteinase-3, IgG, and IgA. Joint swelling had a positive association with SUVmax. Multiple logistic regression analyses revealed that factor associated with increased SUVmax of the joint was joint swelling (P = 0.005). Conclusions: The degree of joint F-18 FDG uptake may contribute to predict active inflammatory process of the joint. In addition, F-18 FDG uptake patterns may have a potential which helps differential diagnosis of CVD-associated arthritis.

Use of 18F-fluoride PET to determine the appropriate tissue sampling region for improved sensitivity of tissue examinations in cases of suspected periprosthetic infection after total hip arthroplasty

Background and purpose The accurate diagnosis of periprosthetic infection requires assessment of intraoperative tissues. These must be sampled from the appropriate sites. We used 18F-fluoride positron emission tomography (PET) to identify sites of inflammation in order to improve the sensitivity of histopathology, microbiological culture, and real-time PCR in total hip arthroplasty (THA) patients. Patients and methods 23 THA patients (23 hips) scheduled for revision surgery (the revision group) and 17 uninfected THA patients (23 hips; control group) were enrolled. Uptake was classified into major, minor, and no uptake. To evaluate the association between the 18F-fluoride uptake and intraoperative tissue results in the revision group, we calculated their sensitivity on each of the major, minor, and no-uptake sides. Results 17 revision patients showed major uptake and all were diagnosed as having septic loosening from intraoperative tissue results. Minor uptake was observed in the other 6 revision patients and all were diagnosed as having aseptic loosening. Apart from 3 cases that showed minor uptake regions, control subjects showed no uptake. In the revision group, the sensitivities of histopathology, microbiological culture, real-time PCR separately and also in combination were 0.78, 0.58, 0.96, and 0.96, respectively, on the major 18F-fluoride uptake sides, 0.0, 0.0, 0.1, and 0.1 on the minor-uptake sides, and 0, 0, 0.18, and 0.18 on the no-uptake sides. Interpretation Our findings suggest that preoperative assessment of major uptake of 18F-fluoride markedly improves the accuracy of tissue sampling, and thus the sensitivity of subsequent tissue examinations. More definitive diagnosis of periprosthetic infection is therefore possible.

18F-Fluoride PET/CT allows detection of hyperostosis and osseous involvement in meningioma: initial experience.

Purpose The present study was conducted to assess the diagnostic performance of 18F-fluoride PET/CT in evaluating hyperostosis and osseous involvement in patients with meningioma. Patients and Methods Thirty-four patients with meningioma (mean age, 61 years) underwent 18F-fluoride PET/CT before surgery. In 24 patients (71%), 18F-FDG PET/CT was also given before surgery, and the results were compared. The images were reviewed by 2 board-certified nuclear medicine specialists who were unaware of any clinical information and a consensus was reached. Uptake patterns and measurements of tracers were compared with pathological findings from resected specimens, with hyperostosis and osseous involvement as the reference standard. Results There were 27 grade I tumors (79%) and 7 grade II tumors (21%). The primary tumor focus was identified in each patient using both 18F-fluoroide PET/CT and 18F-FDG PET/CT, but there were no significant correlations in the degree of uptake between the 2 tracers. The SUVmax, SUVmax corrected for lean body mass (SULmax), and tumor metabolic volume (TMV) for 18F-fluoride and 18F-FDG were greater in grade II tumors than in grade I tumors. Hyperostosis and osseous involvement was identified in 12 tumors (38%). The SUVmax, SULmax, and TMV of tumors visualized with 18F-fluoride PET/CT were greater in tumors with hyperostosis and osseous involvement than in those without (P = 0.005, P = 0.003, and P = 0.006, respectively). In contrast, the SUVmax, SULmax, and TMV of tumors visualized with 18F-FDG PET/CT were similar regardless of hyperostosis or osseous involvement. Conclusions 18F-fluoride PET/CT may improve detection of hyperostosis and osseous involvement in patients with meningioma.

Multiple extra-articular synovial cysts complicated with rheumatoid arthritis.

Multiple extra-articular synovial cysts (MESC) are rarely complicated with various rheumatic diseases. We here first report a rheumatoid arthritis (RA) patient with MESC, which were extensively analyzed by a series of imaging techniques including fluorine-18-2-fluoro-d-glucose positron emission tomography (18F-FDG-PET), magnetic resonance imaging (MRI), and ultrasonography. FDG uptakes in joint lesions with MESC were much higher than those reported in typical lesions of RA, suggesting that marked joint inflammation is implicated in the development of MESC.

Biodistribution and radiation dosimetry of [18F]-5-fluorouracil

PURPOSE To estimate the radiation dose and biodistribution of (18)F-5-fluorouracil ([(18)F]-5-FU) from positron emission tomography/computed tomography (PET/CT) data, and to extrapolate mouse data to human data in order to evaluate cross-species consistency. METHODS Fifteen cancer patients (head and neck cancer (n=11), colon cancer (n=4)) were enrolled. Sequential PET/CT images were acquired for 2h after intravenous administration of [(18)F]-5-FU, and the percent of the injected dose delivered to each organ was derived. For comparison, [(18)F]-5-FU was administered to female BALB/cAJcl-nu/nu nude mice (n=19), and the percent of the injected dose delivered to mouse organs was extrapolated to the human model. Absorbed radiation dose was calculated using OLINDA/EXM 1.0 software. RESULTS In human subjects, high [(18)F]-5-FU uptake was seen in the liver, gallbladder and kidneys. The absorbed dose was highest in the gallbladder wall. In mice, the biodistribution of [(18)F]-5-FU corresponded to that of humans. Estimated absorbed radiation doses for all organs were moderately correlated, and doses to organs (except the gallbladder and urinary bladder) were significantly correlated between mice and humans. The mean effective [(18)F]-5-FU dose was higher in humans (0.0124mSv/MBq) than in mice (0.0058mSv/MBq). CONCLUSION Biodistribution and radiation dosimetry of [(18)F]-5-FU were compared between humans and mice: biodistribution in mice and humans was similar. Data from mice underestimated the effective dose in humans, suggesting that clinical measurements are needed for more detailed dose estimation in order to ensure radiation safety. The observed effective doses suggest the feasibility of [(18)F]-5-FU PET/CT for human studies.