Annals of Nuclear Medicine (v.24, #6)

Prevalence of positive FDG-PET findings in patients with high CEA levels by Tsuyoshi Suga; Yuji Nakamoto; Tsuneo Saga; Tatsuya Higashi; Tadashi Hara; Koichi Ishizu; Hidemitsu Nishizawa; Kaori Togashi (433-439).
The purpose of this study was to evaluate the prevalence of positive findings of positron emission tomography (PET) with 2-deoxy-2-[18F]fluoro-d-glucose (FDG) in patients with high serum CEA levels.A total of 303 patients who had undergone an FDG-PET scan in our institution with high serum CEA levels were analyzed. The prevalence of positive PET findings was evaluated with regard to a previous history of malignancy, absolute value of CEA levels, and the time course of CEA levels (an increasing or decreasing pattern, a change divided by time (ΔCEA) and doubling time of CEA).Of 303 patients, 232 were confirmed to have malignancy, and the patient-based sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of PET were 87, 86, 95, 66, and 86%, respectively. There was no statistically significant difference in positive rates according to the history of previous malignancy. The prevalence of PET-positive cases was higher with an increase in absolute CEA levels, and more than 90% of the patients were positive when CEA levels were more than 20 ng/ml. The ΔCEA was significantly higher and the doubling time was significantly shorter in patients with positive results than those with negative results.A high value of serum CEA levels was correlated with a higher prevalence of positive PET findings. FDG-PET scans would be justified in patients with high serum CEA levels, regardless of whether there was or was not a previous history of malignancy.
Keywords: FDG; PET; CEA; Cancer; Screening

Initial experience with 18F-fluoroethylcholine PET/CT in staging and monitoring therapy response of advanced renal cell carcinoma by Marcus Middendorp; Luise Maute; Bruno Sauter; Thomas J. Vogl; Frank Grünwald (441-446).
The use of 18F-fluoroethylcholine (FEC) PET/CT in staging and monitoring therapy response of advanced renal cell carcinoma (RCC) was prospectively analysed.Preliminary results of two patients with metastatic RCC who underwent tumour nephrectomy as well as FEC PET/CT before and 10 weeks after two cycles of tyrosine kinase inhibitor therapy are presented.All in all, 18 tumour lesions were detected by baseline PET/CT, of which 10 (56%) were positive in FEC PET and 17 (94%) visible on contrast-enhanced computed tomography (ceCT). Mainly, small lung metastases resulted in the lower detection rate of FEC PET compared with ceCT. In follow-up PET/CT of the first case, progressive disease (PD) occurred with increase in tumour diameters of all metastases but non-uniform metabolic response. In the second case, partial response (PR) was achieved with concordant results of PET and CT. These results were confirmed by further CT in the course of disease.In this small sample more than half of the RCC metastases were evident in baseline FEC PET. Monitoring therapy, FEC PET showed heterogeneous results in the first case with PD and was consistent with ceCT in the second one displaying PR.
Keywords: PET/CT; Fluoroethylcholine; Renal cell carcinoma

Estimation of postoperative forced expiratory volume in 1 s (FEV1) with radionuclide lung scintigraphy is frequently used to define functional operability in patients undergoing lung resection. We conducted a study to outline the reliability of planar quantitative lung perfusion scintigraphy (QLPS) with two different processing methods to estimate the postoperative lung function in patients with resectable lung disease.Forty-one patients with a mean age of 57 ± 12 years who underwent either a pneumonectomy (n = 14) or a lobectomy (n = 27) were included in the study. QLPS with Tc-99m macroaggregated albumin was performed. Both three equal zones were generated for each lung [zone method (ZM)] and more precise regions of interest were drawn according to their anatomical shape in the anterior and posterior projections [lobe mapping method (LMM)] for each patient. The predicted postoperative (ppo) FEV1 values were compared with actual FEV1 values measured on postoperative day 1 (pod1 FEV1) and day 7 (pod 7 FEV1).The mean of preoperative FEV1 and ppoFEV1 values was 2.10 ± 0.57 and 1.57 ± 0.44 L, respectively. The mean of Pod1FEV1 (1.04 ± 0.30 L) was lower than ppoFEV1 (p < 0.0001) but increased on day 7 (1.31 ± 0.32 L) (p < 0.0001); however, it never reached the predicted values. Zone and LMMs estimated mean ppoFEV1 as 1.56 ± 0.45 and 1.57 ± 0.44 L, respectively. Both methods overestimated the actual value by 50% (ZM), 51% (LMM) and 19% (ZM), 20% (LMM) for pod 1 and pod 7, respectively. This overestimation was more pronounced in patients with chronic lung disease and hilar tumors. No significant differences were observed between ppoFEV1 values estimated by ZM or by LMM (p > 0.05).PpoFEV1 values predicted by both the zone and LMMs overestimated the actual measured lung volumes in patients undergoing pulmonary resection in the early postoperative period. LMM is not superior to ZM.
Keywords: Lung resection; Quantitative scintigraphy; FEV1, lung perfusion

Several recent studies have shown that bee venom (BV) has an anti-nociceptive and anti-inflammatory effect on arthritis. However, objective methods for evaluation of the therapeutic effect of BV is insufficient in animal studies and clinical trials. Our purpose was to determine the usefulness of bone scintigraphy using Tc-99m DPD (3,3-diphosphono-1,2-propan-dicarbonacid) about effects of BV applied to carrageenan-induced mono-arthritis (CIA) model.Mono-arthritis was induced by an intra-articular injection of carrageenan in Sprague–Dawley rats. Administration of BV (0.8 mg/kg) was performed at 30 min before and at 4 h after the induction of mono-arthritis. We assigned rats to BV-before, BV-after, control-before and control-after groups and compared the results of each group by the weight-loading test and bone scintigraphy. The rats received an intravenous injection of 37 MBq of Tc-99m DPD by the tail vein and then scanning was performed at 4 and 24 h after the injection. Visual assessment and quantitative analysis were performed for both knees.The BV-before and BV-after groups were more improved than the control groups on the weight load test (p < 0.05). Bone scintigraphy showed lower activity in the BV-before group than in the control-before group (p < 0.05) on the 4 h imaging. However, a significant difference in the BV-before and BV-after groups was not observed on the 24 h imaging.BV had therapeutic effects by anti-nociceptive and anti-inflammatory activity in the CIA and bone scintigraphy performed on 4 h imaging provided visual and quantitative information for the assessment of the therapeutic response to BV as an objective method in mono-arthritis model.
Keywords: Bee venom; Osteoarthritis; Bone scintigraphy

Long-term performance evaluation of positron emission tomography: analysis and proposal of a maintenance protocol for long-term utilization by Shoichi Watanuki; Manabu Tashiro; Masayasu Miyake; Yoichi Ishikawa; Masatoshi Itoh; Kazuhiko Yanai; Yasuhiro Sakemi; Hiroshi Fukuda; Keizo Ishii (461-468).
Positron emission tomography (PET) scanners require periodic monitoring in order to maintain scanner performance. The aim of the present study was to examine the deterioration of PET scanner performance caused by aging.We retrospectively examined PET scanner performance alterations in terms of sensitivity, spatial resolution, false coincidences due to scatter and random coincidences based on 13 years of follow-up data, including data when the PET scanner underwent an overhaul at the 10th year after installation. Sensitivity and scatter fraction were calculated by using cross calibration factor (CCF) measurement data, which are collected routinely. Efficacy of the examining the sensitivity and scatter was confirmed by NEMA measurements. Trans-axial resolution was measured as full width at half-maximum (FWHM) and full width at tenth-maximum (FWTM) at 0–20 cm offset from the field of view (FOV) center at the time of installation, 8 years after installation, and immediately after the overhaul. Random coincidence rate fraction was measured in a wide range of count rates before and after the overhaul.The results indicated that the total reduction of sensitivity during the first 10 years was 41% of the initial value in terms of NEMA measurement, and that the annual reduction of sensitivity progressed at a rate of 4.7% per year in terms of CCF measurement data. The changes in sensitivity can be calculated using CCF measurement data. Regarding the spatial resolution, mean FWHM and FWTM values were increased by 1.7 and 3.6%, respectively, in 8 years after installation. The relative scatter fraction was significantly increased compared with that before the overhaul. The random fraction decreased by 10–15% after the overhaul within a certain range of random count rates (1–120 kcps). In the case of our scanner, the parameter that displayed the largest change was the sensitivity, and this change was thought to be caused by the reduction of photomultiplier tube (PMT) gain, although the changes in PMT gain can cause various types of performance deterioration, as investigated in this study.We observed that the sensitivity of our PET scanner generally deteriorated due to aging. Sensitivity monitoring using CCF measurements can be an easy and useful method for monitoring and maintaining the performance of PET scanners against aging. Since the data were obtained from a single scanner, the authors would encourage the initiation of a follow-up study involving various scanners.
Keywords: Positron emission tomography (PET); Quality control; Cross calibration

Relationship between exercise capacity and cardiac diastolic function assessed by time–volume curve from 16-frame gated myocardial perfusion SPECT by Tomohide Yoshino; Ichiro Nakae; Tetsuya Matsumoto; Kenichi Mitsunami; Minoru Horie (469-476).
Echocardiographic studies have suggested an association between diastolic dysfunction and exercise intolerance. The aim of this study was to examine the relationship between exercise capacity and left ventricular (LV) function during stress myocardial scintigraphy, and to investigate whether or not this relationship is caused by ischemia during exercise.The studied patients underwent technetium-99m sestamibi quantitative gated SPECT, including treadmill exercise. Myocardial stress images were acquired 30 min after the first tracer injection (370 MBq) during maximal exercise. Three hours later, the second tracer (740 MBq) was injected, and resting images were acquired 30 min after this injection. The presence of ischemia was determined by tracer accumulation. From the same data source, LV diastolic parameters [first third filling fraction (1/3FF), first third filling rate (1/3FR), peak filling rate (PFR) and time to PFR (TPF)], and systolic parameters [ejection fraction (EF), peak ejection rate (PER), time to PER (TPE) and first third ejection fraction (1/3EF)] were analyzed.Subjects with exercise inability (<6 METs) were excluded. In 45 patients, diastolic parameters 1/3FF, 1/3FR, PFR and TPF correlated significantly with exercise duration (r = 0.32*, 0.37*, 0.37* and −0.40#, respectively; *p < 0.05, # p < 0.01), but systolic parameters EF, PER, TPE and 1/3EF did not. At rest, 1/3FF, PFR and PER were significantly increased, suggesting functional deterioration during exercise. Even after 3 h, 1/3FR, PFR and TPF still correlated significantly with exercise duration (r = 0.29*, 0.36* and −0.30*, respectively; *p < 0.05). Such findings were observed even when the 10 patients who exhibited ischemia during exercise were excluded (1/3FR: r = 0.34*; PFR: r = 0.37*; TPF: r = −0.36*; *p < 0.05, n = 35).Our findings suggested that LV diastolic dysfunction, not systolic dysfunction, is associated with limited exercise capacity independent of the occurrence of ischemia.
Keywords: Diastolic function; Myocardial ischemia; Exercise capacity; Myocardial scintigraphy

SPECT/CT stabilizes the interpretation of somatostatin receptor scintigraphy findings: a retrospective analysis of inter-rater agreement by Ivayla Apostolova; Swantje Riethdorf; Ralph Buchert; Thorsten Derlin; Winfried Brenner; Janos Mester; Susanne Klutmann (477-483).
Correlating the anatomical information from CT with the functional information from SPECT improves diagnostic accuracy of somatostatin-receptor-scintigraphy (SRS) in patients with neuroendocrine tumors (NET). The aim of the present study was to investigate the impact of dual modality SPECT/CT on the inter-rater agreement in SRS.Twenty-five unselected patients with suspected or histologically proven NET in whom whole body planar imaging and low-dose SPECT/CT had been performed after injection of 200 MBq In-111-octreotide were included retrospectively. Images were interpreted independently by 2 nuclear medicine physicians, an experienced one and an inexperienced one. Both readers first re-evaluated the planar whole-body images alone, then added the SPECT images, and finally the CT-images. Lesions with pathologically increased tracer uptake were categorized according to the following 3-point score: equivocal, probably pathologic, and definitely pathologic. Cohen’s linear-weighted kappa coefficient κ was used to quantify inter-rater agreement.A total number of 50 lesions were described in 23 of the 25 patients. The two readers showed only moderate agreement in the interpretation of the planar findings (κ = 0.593). Agreement improved to substantial by adding SPECT (κ = 0.736) and to very good by adding SPECT/CT (κ = 0.860). SPECT/CT resulted in up-staging of 18% of the lesions and down-staging of 12% compared to planar + SPECT (experienced reader). In addition, SPECT/CT tended to reduce the frequency of indefinite scores (equivocal, probably pathologic), from 18% in planar + SPECT to 6% (p = 0.065). Change of lesion localization by SPECT/CT tended to contribute to the change of lesion score (p = 0.055).The present results suggest that low-dose SPECT/CT stabilizes report quality in SRS by improving inter-rater agreement.
Keywords: In-111-octreotide; Somatostatin receptor scintigraphy; Neuroendocrine tumor; SPECT/CT; Inter-rater agreement

Role of 11C-choline PET/CT in the restaging of prostate cancer patients showing a single lesion on bone scintigraphy by Chiara Fuccio; Paolo Castellucci; Riccardo Schiavina; Ivan Santi; Vincenzo Allegri; Vincenzina Pettinato; Stefano Boschi; Giuseppe Martorana; Adil Al-Nahhas; Domenico Rubello; Stefano Fanti (485-492).
To assess the utility of 11C-choline PET/CT in the restaging of prostate cancer (PC) patients who showed a single finding on bone scintigraphy (BS) that was classified as equivocal or suspected for metastatic lesion.A total of 25 PC patients with biochemical failure (mean PSA value 11.1 ng/mL; median value 6.3 ng/mL; range 0.2–37.7 ng/mL) after primary treatment were included in this retrospective study. All of them showed a single lesion on BS reported as suspected for metastatic lesion or as equivocal finding. Patients underwent 11C-choline PET/CT within 1–4 months from BS. Validation was established by follow-up for at least 6 months.On the basis of biopsy confirmation and/or 6-month follow-up, 22 of 25 patients were classified as positive for the presence of metastatic bone lesions: 13 with a single lesion and 9 with multiple lesions. 11C-choline PET/CT was positive in 19/25 patients and, on a lesion basis, it showed 50 positive findings. BS results were confirmed in 8/25 (32%) patients. 11C-choline PET/CT detected multiple sites of relapse in 11/25 (44%) patients: in 2/11, a single bone lesion associated with other extraosseous sites of relapse; in 6/11, multiple bone lesions; in 3/11, multiple bone lesions and other extraosseous localizations. Finally, 6/25 patients were negative on 11C-choline PET/CT. In 3/6 patients, an osteoblastic lesion was seen on CT attenuation correction images (PET false negative; BS true positive), while in 3/6 patients only findings suggestive of the presence of degenerative disease were found (PET true negative; BS false positive). On a patient basis, 11C-choline PET/CT showed a diagnostic sensitivity of 86% (19/22) and a specificity of 100% (19/19).In our study, 11C-choline PET/CT detected unknown lesions in 11/25 patients. Patients with a single equivocal finding on BS could have important additional information from 11C-choline PET/CT study, especially in the detection of additional metastases, to choose an appropriate treatment.
Keywords: Prostate cancer; Positron emission tomography (PET); Choline; PSA; Bone scan

18F-FDG PET/CT findings of pharyngeal tuberculosis by Kimiteru Ito; Miyako Morooka; Kazuo Kubota (493-496).
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.
Keywords: Pharyngeal tuberculosis; Dysphagia; Tuberculosis; FDG; PET/CT

Takotsubo cardiomyopathy following dipyridamole pharmacologic stress by Angela S. Koh; Henry Kok; Terrance Chua; Felix Keng (497-500).
This study is about an elderly female patient who presented with rapid atrial fibrillation. Pharmacologic stress myocardial perfusion imaging with dipyridamole for the assessment of myocardial ischemia resulted in transient abnormalities on electrocardiogram, wall motion and perfusion defects with complete resolution 1 month later, suggestive of Takotsubo cardiomyopathy. We believe that our case report is the first to describe this finding after dipyridamole stress.
Keywords: Stress cardiomyopathy; Dipyridamole

Normoglycemic plasma glucose levels affect F-18 FDG uptake in the brain by Jonas Claeys; Koen Mertens; Yves D’Asseler; Ingeborg Goethals (501-505).
The aim of this study was to investigate whether normoglycemic glucose concentrations interfere with cerebral F-18 FDG uptake.The analysis was based on 2 sets of paired PET scans in 94 patients who were in complete metabolic remission after the successful completion of treatment for lymphoma. For these 188 PET scans, 2 subgroups were defined according to the plasma glucose level at the time of scanning. Group 1 contained the PET images that were associated with the lower of both normoglycemic plasma glucose levels, whereas group 2 contained the PET images that were associated with the higher of both plasma glucose levels. SUVs (standard uptake values) in the cerebellum between both groups were compared using paired sample T test. Subsequently, SUVs were normalized to a standard glucose concentration and normalized SUVs were again compared. Further, we calculated the coefficient of variation of SUVs in group 1 and 2 both before and after the normalization step.Mean plasma glucose level was 86 mg/dL (SD of 9 mg/dL) in group 1 and 97 mg/dL (SD of 10 mg/dL) in group 2. Mean SUV was 3.8 (SD of 1.1) for group 1 and 3.5 (SD of 1.1) for group 2. Mean SUV in group 1 was slightly but statistically significantly higher than the mean SUV in group 2 (p < 0.01). Mean normalized SUV was 3.6 (SD of 1.1) in group 1 and 3.7 (SD of 1.3) in group 2. A paired comparison between normalized SUVs in both groups indicated that there was no statistically significant difference (p < 0.31). The coefficient of variation for the SUVs in group 1 and 2 before normalization was 29 and 30%, respectively. The coefficient of variation for the normalized SUVs in group 1 and 2 was 30 and 34%, respectively.Our results indicated that plasma glucose levels that are within the normoglycemic range have a small but systematic effect on F-18 FDG uptake in the brain (following an inverse relationship). Normalizing plasma glucose levels to a standard glucose concentration successfully reduced the intra-subject variability of SUV measures. Inter-subject variability, however, remained high suggesting that other factors have an influence as well.
Keywords: Normoglycemia; Brain metabolism; PET; SUV