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1.
Breast imaging. Preoperative breast cancer staging: comparison of USPIO-enhanced MR imaging and 18F-fluorodeoxyglucose (FDC) positron emission tomography (PET) imaging for axillary lymph node staging--initial findings.
Stadnik, TW, Everaert, H, Makkat, S, Sacré, R, Lamote, J, Bourgain, C
European radiology. 2006;(10):2153-60
Abstract
Magnetic resonance (MR) imaging after ultra-small super paramagnetic iron oxide (USPIO) injection and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) for preoperative axillary lymph node staging in patients with breast cancer were evaluated using histopathologic findings as the reference standard. USPIO-enhanced MR and FDG-PET were performed in ten patients with breast cancer who were scheduled for surgery and axillary node resection. T2-weighted fast spin echo, T1-weighted three-dimensional (3D) gradient echo, T2*-weighted gradient echo and gadolinium-enhanced T1-weighted 3D gradient echo with spectral fat saturation were evaluated. MR imaging before USPIO infusion was not performed. The results were correlated with FDG-PET (acquired with dedicated PET camera, visual analysis) and histological findings. The histopathologic axillary staging was negative for nodal malignancy in five patients and positive in the remaining five patients. There was one false positive finding for USPIO-enhanced MR and one false negative finding for FDG-PET. A sensitivity (true positive rate) of 100%, specificity (true negative rate) of 80%, positive predictive value of 80%, and negative predictive value of 100% were achieved for USPIO-enhanced MR and of 80%, 100%, 100%, 80% for FDG-PET, respectively. The most useful sequences in the detection of invaded lymph nodes were in the decreasing order: gadolinium-enhanced T1-weighted 3D gradient echo with fat saturation, T2*-weighted 2D gradient echo, T1-weighted 3D gradient echo and T2-weighted 2D spin echo. In our study, USPIO-enhanced T1 gradient echo after gadolinium injection and fat saturation emerged as a very useful sequence in the staging of lymph nodes. The combination of USPIO-enhanced MR and FDG-PET achieved 100% sensitivity, specificity, PPV and NPV. If these results are confirmed, the combination of USPIO MR with FDG-PET has the potential to identify the patient candidates for axillary dissection versus sentinel node lymphadenectomy.
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2.
[18F]FDG in recurrent breast cancer: diagnostic performances, clinical impact and relevance of induced changes in management.
Grahek, D, Montravers, F, Kerrou, K, Aide, N, Lotz, JP, Talbot, JN
European journal of nuclear medicine and molecular imaging. 2004;(2):179-88
Abstract
Prognosis and management of patients with recurrent breast cancer depend on the spread of the disease. The aim of this study was to evaluate the performance of fluorine-18 fluorodeoxyglucose gamma camera positron emission tomography (FDG-GPET) in detecting breast cancer recurrence, its clinical impact and the relevance of induced changes in management. Patients (n = 134) with suspicion of recurrence either clinically or on conventional imaging (suspected recurrence: SR) or with an isolated increase in tumour marker levels (occult recurrence: OR) underwent FDG-GPET on a coincidence gamma camera. The reference standard for evaluation of accuracy, either histology (n = 26) or follow-up for 1 year (n = 49), was available in 75 (56%) patients. A questionnaire was sent to the referring clinician to evaluate the impact of FDG on management. Responses were obtained for 75 patients. Information regarding both approaches was available for 46 patients (46/134 = 34%). At the patient level, the sensitivity of FDG-GPET was 84%, significantly higher than the 63% sensitivity for conventional modalities, and the specificity was 78% versus 61%. The values for FDG-GPET were 81% and 86% respectively in the SR group and 90% and 73% respectively in the OR group, without any significant difference between these settings. The rate of change in management was 44% overall, 43% in the SR group and 45% in the OR group. Within the two groups, intermodality (major) changes were more frequent than intramodality (minor) changes. In the 46 patients for whom both approaches were available, 93% of management modifications were relevant (validated by biopsy or clinical follow-up). The results of this retrospective study show that FDG-GPET has an important role to play in patient management by confirming and evaluating the extent of recurrence or by localising occult recurrence.
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3.
The modelling of positron emitter production and PET imaging during carbon ion therapy.
Pönisch, F, Parodi, K, Hasch, BG, Enghardt, W
Physics in medicine and biology. 2004;(23):5217-32
Abstract
At the carbon ion therapy facility of GSI Darmstadt in-beam positron emission tomography (PET) is used for imaging the beta+-activity distributions which are produced via nuclear fragmentation reactions between the carbon ions and the atomic nuclei of the irradiated tissue. On the basis of these PET images the quality of the irradiation, i.e. the position of the field, the particle range in vivo and even local deviations between the planned and the applied dose distribution, can be evaluated. However, for such an evaluation the measured beta+-activity distributions have to be compared with those predicted from the treatment plan. The predictions are calculated as follows: a Monte Carlo event generator produces list mode data files of the same format as the PET scanner in order to be processed like the measured ones for tomographic reconstruction. The event generator models the whole chain from the interaction of the projectiles with the target, i.e. their stopping and nuclear reactions, the production and the decay of positron emitters, the motion of the positrons as well as the propagation and the detection of the annihilation photons. The steps of the modelling, the experimental validation and clinical implementation are presented.
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4.
Human positron emission tomography studies of brain neurokinin 1 receptor occupancy by aprepitant.
Bergström, M, Hargreaves, RJ, Burns, HD, Goldberg, MR, Sciberras, D, Reines, SA, Petty, KJ, Ogren, M, Antoni, G, Långström, B, et al
Biological psychiatry. 2004;(10):1007-12
Abstract
BACKGROUND Aprepitant is a highly selective substance P (neurokinin 1 [NK(1)] receptor) antagonist that significantly improves the pharmacotherapy of acute and delayed highly emetogenic chemotherapy-induced nausea and vomiting, probably through an action in the brain stem region of the central nervous system. Here, we report the use of positron emission tomography imaging with the NK(1) receptor binding-selective tracer [(18)F]SPA-RQC to determine the levels of central NK(1) receptor occupancy achieved by therapeutically relevant doses of aprepitant in healthy humans. METHODS Two single-blind, randomized, placebo-controlled studies in healthy subjects were performed. The first study evaluated the plasma concentration-occupancy relationships for aprepitant dosed orally at 10, 30, 100, or 300 mg, or placebo (n = 12). The second study similarly evaluated oral aprepitant 30 mg and placebo (n = 4). In each study, dosing was once daily for 14 consecutive days. Data from both studies were combined for analyses. The ratio of striatal/cerebellar [(18)F]SPA-RQ (high receptor density region/reference region lacking receptors) was used to calculate trough receptor occupancy 24 hours after the last dose of aprepitant. RESULTS Brain NK(1) receptor occupancy increased after oral aprepitant dosing in both a plasma concentration-related (r =.97; 95% confidence interval [CI] =.94-1.00, p <.001) and a dose-related (r =.94; 95% CI =.86-1.00, p <.001) fashion. High (> or =90%) receptor occupancy was achieved at doses of 100 mg/day or greater. The plasma concentrations of aprepitant that achieved 50% and 90% occupancy were estimated as approximately 10 ng/mL and approximately 100 ng/mL, respectively. CONCLUSIONS Positron emission tomography imaging with [(18)F]SPA-RQ allows brain NK(1) receptor occupancy by aprepitant to be predicted from plasma drug concentrations and can be used to guide dose selection for clinical trials of NK(1) receptor antagonists in central therapeutic indications.
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5.
PET and SPECT for detection of tumor progression in irradiated low-grade astrocytoma: a receiver-operating-characteristic analysis.
Henze, M, Mohammed, A, Schlemmer, HP, Herfarth, KK, Hoffner, S, Haufe, S, Mier, W, Eisenhut, M, Debus, J, Haberkorn, U
Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 2004;(4):579-86
Abstract
UNLABELLED Differentiation between tumor progression and radiation necrosis is one of the most difficult tasks in oncologic neuroradiology. Functional imaging of tumor metabolism can help with this task, but the choice of tracer is still controversial. This prospective study following up irradiated low-grade astrocytoma (LGA) was, to our knowledge, the first receiver-operating-characteristic (ROC) analysis that intraindividually evaluated the diagnostic performance of the SPECT tracers 3-[(123)I]iodo-alpha-methyl-L-tyrosine (IMT) and (99m)Tc(I)-hexakis(2-methoxyisobutylisonitrile) (MIBI) and the PET tracer (18)F-FDG. METHODS We examined 17 patients, initially with histologically proven LGA and treated by stereotactic radiotherapy, who presented with new gadolinium-diethylenetriaminepentaacetic acid-enhancing lesions (n = 26) on MRI. At that time, MRI could not differentiate between progressive tumor and nonprogressive tumor. This MRI examination was closely followed by (18)F-FDG PET and by (99m)Tc-MIBI and (123)I-IMT SPECT. Lesions were classified as progressive tumor (n = 17) or nonprogressive tumor (n = 9) on the basis of prospective follow-up (through clinical examination, MRI, and proton MR spectroscopy) for 26.6 +/- 6.6 mo after PET or SPECT. RESULTS (123)I-IMT yielded the best ROC characteristics and was the most accurate for classification, with an area under the ROC curve (A(z)) of 0.991. The A(z) of (18)F-FDG (0.947) was not significantly lower than that of (123)I-IMT. The difference in the A(z) of (99m)Tc-MIBI (0.713) from the A(z) of the other tracers used in our study was highly significant (P ≤ 0.01). (99m)Tc-MIBI SPECT was of low accuracy and, especially, of poor sensitivity even at modest specificity values. CONCLUSION (123)I-IMT SPECT imaging of amino acid transport accurately detects tumor progression in patients with irradiated LGA. In contrast to (123)I-IMT, (18)F-FDG PET was slightly less accurate for classification, and (99m)Tc-MIBI SPECT was of limited value. Imaging of amino acid transport with (123)I-IMT is a valuable additional tool for the follow-up of LGA, allowing early, noninvasive differentiation of lesions with ambiguous morphology after irradiation.
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6.
[18F]FDG PET as a substitute for second-look laparotomy in patients with advanced ovarian carcinoma.
Kim, S, Chung, JK, Kang, SB, Kim, MH, Jeong, JM, Lee, DS, Lee, MC
European journal of nuclear medicine and molecular imaging. 2004;(2):196-201
Abstract
The aim of this study was to compare the prognostic value of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) with that of second-look laparotomy (SLL) in patients with advanced ovarian carcinoma following primary chemotherapy. Fifty-five patients who had undergone cytoreductive surgery and adjuvant chemotherapy for advanced ovarian carcinoma were enrolled in the study. Thirty patients underwent SLL after primary treatment (SLL group), while 25 underwent FDG PET after primary treatment without SLL (PET group) We retrospectively reviewed the medical records of the 55 patients for comparison of progression-free interval and disease-free interval between the two groups. Ovarian carcinomas recurred in 37 of the 55 patients. When the progression-free interval and the disease-free interval in patients in the PET group were compared with those in the SLL group, no significant differences were observed. The progression-free interval in the PET and SLL groups were 28.8 +/- 12.7 months and 30.6 +/- 13.7 months, respectively (P = 0.29). The disease-free interval in the negative PET group was 40.5 +/- 11.6 months, and that in the negative SLL group was 48.6 +/- 12.1 months (P = 0.12). In conclusion, FDG PET has a similar prognostic value to SLL, and can substitute for SLL in the follow-up of patients who have had ovarian carcinoma, especially when there is a high risk for recurrence.
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7.
Baseline/post-nitrate Tc-99m tetrofosmin mismatch for the assessment of myocardial viability in patients with severe left ventricular dysfunction: comparison with baseline Tc-99m tetrofosmin scintigraphy/FDG PET imaging.
Giorgetti, A, Marzullo, P, Sambuceti, G, Di Quirico, S, Kusch, A, Landi, P, Salvadori, PA, Pisani, P, L'abbate, A
Journal of nuclear cardiology : official publication of the American Society of Nuclear Cardiology. 2004;(2):142-51
Abstract
BACKGROUND Positron emission tomography (PET) flow/metabolic mismatch is considered the nuclear medicine gold standard for the assessment of myocardial viability. The aim of this study was to investigate whether baseline/nitrate technetium 99m tetrofosmin single photon emission computed tomography (SPECT) mismatch may provide equivalent clinical information. METHODS AND RESULTS We studied 23 patients (aged 62 +/- 10 years, 19 men) with previous myocardial infarction (16 anterior, 4 inferior, and 3 anterior plus inferior) and postischemic heart failure (gated SPECT [G-SPECT] ejection fraction, 26% +/- 8%). All patients underwent Tc-99m tetrofosmin G-SPECT at rest and after nitrates (intravenous isosorbide dinitrate, 0.2 mg/mL, 10 mL/h) as well as a fluorine 18 fluoro-2-deoxy-d-glucose (FDG) PET scan. Regional wall motion analysis was performed with quantitative G-SPECT (QGS). Myocardial dysfunction was defined as a regional QGS score of 2 or greater. Regional perfusion was assessed by quantitative perfusion score (QPS) providing percent Tc-99m tetrofosmin uptake in a 20-segment model. Semiquantitative analysis of FDG uptake was performed by use of polar maps generated by Siemens ECAT HR + software. In areas with a perfusion rate lower than 80%, PET viability was identified by a normalized FDG percent uptake/baseline Tc-99m tetrofosmin percent uptake ratio greater than 1.2. We analyzed 460 segments; 298 (64%) were dysfunctional by QGS analysis. Of these, 170 were viable by PET imaging whereas 128 were nonviable. Regional Tc-99m tetrofosmin uptake was higher in viable than in nonviable segments both at rest (60% +/- 24% vs 42% +/- 12%, P <.01) and after nitrates (67% +/- 20% vs 41% +/- 18%, P <.01). According to receiver operating characteristic curve analysis, a cutoff value of 63% for resting as well as post-nitrate G-SPECT provided the highest diagnostic accuracy for the detection of myocardial viability (67% and 72% at rest and after nitrates, respectively). When the same algorithm used for the comparison with PET (normalized nitrate percent uptake/baseline percent uptake) was applied to G-SPECT, we obtained the highest agreement with PET (accuracy, 93%; sensitivity, 95%; specificity, 92%). CONCLUSIONS In patients with severe left ventricular dysfunction, perfusion data alone, both at rest and after nitrates, do not allow an accurate estimate of myocardial viability. In dysfunctioning segments, the analysis of rest/post-nitrate Tc-99m tetrofosmin mismatch provides results similar to those obtained by PET flow/metabolic mismatch.
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8.
Comparison of O-(2-18F-fluoroethyl)-L-tyrosine PET and 3-123I-iodo-alpha-methyl-L-tyrosine SPECT in brain tumors.
Pauleit, D, Floeth, F, Tellmann, L, Hamacher, K, Hautzel, H, Müller, HW, Coenen, HH, Langen, KJ
Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 2004;(3):374-81
Abstract
UNLABELLED The aim of this study was to compare PET with O-(2-(18)F-fluoroethyl)-L-tyrosine ((18)F-FET) and SPECT with 3-(123)I-iodo-alpha-methyl- L-tyrosine ((123)I-IMT) in patients with brain tumors. METHODS Twenty patients with a suspected brain tumor were investigated by (18)F-FET PET, (123)I-IMT SPECT, and MRI within 3 wk. Region-of-interest analyses were performed on coregistered PET/SPECT/MRI images and the tumor-to-brain ratio (TBR), muscle-to-brain ratio (MBR), cerebellum-to-brain ratio (CerBR), and sinus-to-brain ratio (SBR) were calculated. In addition, the presence of tumor and the discrimination of anatomic structures on (18)F-FET PET and (123)I-IMT SPECT images were visually determined by 3 observers who were unaware of clinical data. RESULTS The TBR of (18)F-FET and (123)I-IMT uptake in cerebral tumors showed a highly significant correlation (r = 0.96; P < 0.001). In the visual analysis for the presence or absence of tumors, no differences for (123)I-IMT SPECT and (18)F-FET PET were found in 19 of 20 patients; in one patient a low-grade glioma was only identified on (18)F-FET PET images but not on (123)I-IMT SPECT images. The contrast between tumor and normal brain was significantly higher in (18)F-FET PET (TBR, 2.0 +/- 0.9) than in (123)I-IMT SPECT (TBR, 1.5 +/- 0.5). The discrimination of anatomic structures yielded a significantly better score on (18)F-FET PET images (rating score, 2.6 +/- 0.9) compared with (123)I-IMT SPECT images (rating score, 1.7 +/- 0.9). The uptake of (18)F-FET in the muscles was significantly higher compared with (123)I-IMT (MBR (18)F-FET, 1.4 +/- 0.3; MBR (123)I-IMT, 0.6 +/- 0.2; P < 0.001) and (18)F-FET demonstrated a significantly higher blood-pool radioactivity than (123)I-IMT (SBR (18)F-FET, 1.3 +/- 0.2; SBR (123)I-IMT, 0.8 +/- 0.2; P < 0.001). CONCLUSION The significant correlation of the TBRs of (18)F-FET and (123)I-IMT indicates that clinical experiences of brain tumor diagnostics with (123)I-IMT SPECT might be valid for (18)F-FET PET although substantial differences of the physiologic behavior were identified in extracerebral tissue. As (18)F-FET PET allows improved discrimination of anatomic structures and the tumor-to-brain contrast was significantly superior compared with (123)I-IMT SPECT scans, the results are encouraging for further evaluation of (18)F-FET for imaging brain tumors.
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9.
The reproducibility of independently measuring human regional hepatic arterial, portal and total hepatic blood flow using [15O]water and positron emission tomography.
Taniguchi, H, Kunishima, S, Koh, T
Nuclear medicine communications. 2003;(5):497-501
Abstract
The reproducibility of repeated human regional hepatic blood flow quantification using [15O]water and positron emission tomography (PET) was evaluated as a method of monitoring the effect of drug administration on hepatic blood flow. Nineteen patients underwent two measurements of hepatic blood flow by PET. Fifteen minutes after the first dynamic study using [15O]water, a second dynamic study was performed, and hepatic blood flow was calculated. The correlation between the first and second dynamic study of arterial blood flow was highly significant (P=6.31 x 10(-10), r=0.946). The regression line was y=1.08x. The mean error between studies was 0.158. The correlation between the first and second dynamic study of portal blood flow also was significant (P=1.29 x 10(-7), r=0.897). The regression line was y=1.03x. The mean error between the studies was 0.164. The correlation between total hepatic blood flow in the first and second dynamic study, too, was significant (P=2.68 x 10(-7), r=0.888). The regression line was defined by y=1.06x. The mean error between studies was 0.140. Hepatic blood flow has increased if the second measurement of hepatic arterial, portal, and total blood flow is more than 115%, 111% and 114% of baseline, and has decreased if the second measurement is less than 101%, 95% and 98% of the first measurement.
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10.
Effect of calcium antagonist on cerebral blood flow and oxygen metabolism in patients with hypertension and chronic major cerebral artery occlusion: a positron emission tomography study.
Ogasawara, K, Noda, A, Yasuda, S, Kobayashi, M, Yukawa, H, Ogawa, A
Nuclear medicine communications. 2003;(1):71-6
Abstract
To evaluate the effect of a calcium antagonist, nilvadipine, on cerebral blood flow and oxygen metabolism, we prospectively examined five ischaemic stroke patients, with both hypertension and chronic major cerebral artery occlusion, using positron emission tomography. The blood pressure showed a significant decrease after 3 months of nilvadipine treatment, the cerebral blood flow in the affected regions showed a significant increase and the oxygen extraction fraction showed a significant decrease. We conclude that nilvadipine is a safe and effective anti-hypertensive agent for patients with both hypertension and chronic major cerebral artery occlusion.