To prospectively evaluate the potential value of fluorocholine (FCH) positron emission tomography (PET)/computed tomography (CT) in the preoperative staging of patients with prostate cancer who had intermediate or high risk of extracapsular disease. Institutional review board approval and written informed consent were obtained. Overall, 132 patients with prostate cancer (mean age, 63 years +/- 7 [standard deviation]) were enrolled between October 2003 and June 2008. Two patients were subsequently excluded. In 111 patients, radical prostatectomy with extended pelvic lymph node (LN) dissection was performed. Patients were categorized into groups with intermediate (n = 47) or high (n = 83) risk of extracapsular extension on the basis of their Gleason scores and prostate specific antigen levels. Imaging was performed with an integrated PET/CT system after injection of 4.07 MBq FCH per kilogram of body weight with acquisition of dynamic images in the pelvis and whole-body images. Statistical analysis was performed on a per-patient basis. Significant correlation was found between sections with the highest FCH uptake and sextants with maximal tumor infiltration (r = 0.68; P = .0001). Overall, 912 LNs were histopathologically examined. A per-patient analysis revealed the sensitivity, specificity, and positive and negative predictive values of FCH PET/CT in the detection of malignant LNs were 45%, 96%, 82%, and 83%, respectively. For LN metastases greater than or equal to 5 mm in diameter, sensitivity, specificity, and positive and negative predictive values were 66%, 96%, 82%, and 92%, respectively. In 13 patients, 43 bone metastases were detected. Early bone marrow infiltration was detected with only FCH PET in two patients. FCH PET/CT led to a change in therapy in 15% of all patients and 20% of high-risk patients. FCH PET/CT could be useful in the evaluation of patients with prostate cancer who are at high risk for extracapsular disease, and it could be used to preoperatively exclude distant metastases. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.09090413/-/DC1.

Purpose In this prospective study we compared the accuracy of ¹⁸F-fluorocholine PET/CT with that of ^99mTc-MIBI or^99mTc-tetrofosmin SPECT/CT in the preoperative detection of parathyroid adenoma in patients with primary hyperparathyroidism. We also assessed the value of semiquantitative parameters in differentiating between parathyroid hyperplasia and adenoma. Methods Both ¹⁸F-fluorocholine PET/CT and ^99mTc-MIBI/tetrofosmin SPECT/CT were performed in 100 consecutive patients with biochemical evidence of primary hyperparathyroidism. At least one abnormal focus on either ¹⁸F-fluorocholine or ^99mTc-MIBI/tetrofosmin corresponding to a parathyroid gland or ectopic parathyroid tissue was considered as a positive finding. In 76 patients with positive findings on at least one imaging modality, surgical exploration was performed within 6 months, and the results were related to histopathological findings and clinical and laboratory findings at 3–6 months as the standard of truth. In 24 patients, no surgery was performed: in 18 patients with positive imaging findings surgery was refused or considered risky, and in 6 patients imaging was negative. Therefore, data from 82 patients (76 undergoing surgery, 6 without surgery) in whom the standard of truth criteria were met, were used in the final analysis. Results All patients showed biochemical evidence of primary hyperparathyroidism with a mean serum calcium level of 2.78 ± 0.34 mmol/l and parathormone (PTH) level of 196.5 ± 236.4 pg/ml. The study results in 76 patients with verified histopathology and 3 patients with negative imaging findings were analysed. Three of six patients with negative imaging showed normalized serum PTH and calcium levels on laboratory follow-up at 3 and 6 months, and the results were considered true negative. In a patient-based analysis, the detection rate with ¹⁸F-fluorocholine PET/CT was 93% (76/82), but was only 61% (50/82) with ^99mTc-MIBI/tetrofosmin SPECT/CT. In a lesion-based analysis, the sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy of ¹⁸F-fluorocholine PET/CT in the detection of parathyroid adenoma were 93.7%, 96.0%, 90.2%, 97.4% and 95.3%, respectively, and of ^99mTc-MIBI/tetrofosmin SPECT/CT were 60.8%, 98.5%, 94.1%, 86.3% and 87.7%, respectively. Although ¹⁸F-fluorocholine PET-positive adenomatous lesions showed higher SUVmax values than the hyperplastic glands (6.80 ± 3.78 vs. 4.53 ± 0.40) in the semiquantitative analysis, the difference was not significant (p = 0.236). The mean size (measured as the length of the greatest dimension) and weight of adenomas were 15.9 ± 7.6 mm (median 15 mm, range 1–40 mm) and 1.71 ± 1.86 g (median 1 g, range: 0.25–9 g), respectively. Among the analysed parameters including serum calcium and PTH and the size and weight of parathyroid adenomas, size was significantly different between patients with negative ^99mTc-MIBI/tetrofosmin SPECT/CT and those with positive ^99mTc-MIBI/tetrofosmin SPECT/CT (mean size 13.4 ± 7.6 mm vs. 16.9 ± 7.4 mm, respectively; p = 0.042). Conclusion In this prospective study, ¹⁸F-fluorocholine PET/CT showed promise as a functional imaging modality, being clearly superior to ^99mTc-MIBI/tetrofosmin SPECT/CT, especially in the detection and localization of small parathyroid adenomas in patients with primary hyperparathyroidism. SUVmax was higher in parathyroid adenomas than in hyperplasia. However, further evaluation of this modality is needed.