Michael Nader

Detection of bone metastases in patients with prostate cancer by 18F fluorocholine and 18F fluoride PET–CT: a comparative study

PurposeThe aim of this prospective study was to compare the potential value of 18F fluorocholine (FCH) and 18F fluoride positron emission tomography (PET)–CT scanning for the detection of bony metastases from prostate cancer.MethodsThirty-eight men (mean age, 69u2009±u20098xa0years) with biopsy-proven prostate cancer underwent both imaging modalities within a maximum interval of 2xa0weeks. Seventeen patients were evaluated preoperatively, and 21 patients were referred for post-operative evaluation of suspected recurrence or progression based on clinical algorithms. The number, sites and morphological patterns of bone lesions on 18F FCH and 18F fluoride PET–CT were correlated: Concordant lesions between the two modalities with corresponding changes on CT were considered to be positive for malignancy; discordant lesions were verified by follow-up examinations. The mean follow-up interval was 9.1xa0months.ResultsOverall, 321 lesions were evaluated in this study. In a lesion-based analysis, a relatively close agreement was found between these two imaging modalities for detection of malignant bone lesions (kappau2009=u20090.57), as well as in a patient-based analysis (kappau2009=u20090.76). Sixteen malignant sclerotic lesions with a high density were negative in both 18F FCH and 18F fluoride PET–CT [mean Hounsfield unit (HU), 1,148u2009±u2009364]. There was also a significant correlation between tracer intensity by SUV and density of sclerotic lesions by HU both in 18F FCH PET–CT (ru2009=u2009−0.28, pu2009<u20090.006) and 18F fluoride PET–CT (ru2009=u2009−0.20, pu2009<u20090.05).The sensitivity, specificity and accuracy of PET–CT in the detection of bone metastases in prostate cancer was 81%, 93% and 86% for 18F fluoride, and 74% (pu2009=u20090.12), 99% (pu2009=u20090.01) and 85% for FCH, respectively.18F FCH PET–CT led to a change in the management in two out of 38 patients due to the early detection of bone marrow metastases. 18F fluoride PET–CT identified more lesions in some patients when compared with 18F FCH PET–CT but did not change patient management.ConclusionFCH PET–CT may be superior for the early detection (i.e. bone marrow involvement) of metastatic bone disease. In patients with FCH-negative suspicious sclerotic lesions, a second bone-seeking agent (e.g. 18F fluoride) is recommended. 18F fluoride PET–CT demonstrated a higher sensitivity than 18F FCH PET–CT, but the difference was not statistically significant. Furthermore, 18F fluoride PET could be also negative in highly dense sclerotic lesions, which presumably reflects the effect of treatment. It will be important to clarify in future studies whether these lesions are clinically relevant when compared with metabolically active bone metastases.

18F choline PET/CT in the preoperative staging of prostate cancer in patients with intermediate or high risk of extracapsular disease: a prospective study of 130 patients.

PURPOSEnTo 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.nnnMATERIALS AND METHODSnInstitutional 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.nnnRESULTSnSignificant 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.nnnCONCLUSIONnFCH 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.nnnSUPPLEMENTAL MATERIALnhttp://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.09090413/-/DC1.

The Use of F-18 Choline PET in the Assessment of Bone Metastases in Prostate Cancer: Correlation with Morphological Changes on CT

AimF-18 fluor choline-positron emission tomography/computed tomography (FCH-PET/CT) has emerged as a new diagnostic tool for the imaging of prostate cancer. In this study, we have evaluated the potential role of FCH-PET/CT for the assessment of bone metastases in patients with prostate cancer. Furthermore, we assessed the pattern of metabolic uptake by FCH in relation to morphologic changes on CT.MethodsSeventy men with biopsy-proven prostate cancer underwent FCH-PET/CT for preoperative staging or follow-up evaluation. Thirty-two patients were evaluated preoperatively, and 38 patients were referred for post operative evaluation of suspected recurrence or progression based on clinical algorithms. PET imaging consisted of a dynamic PET/CT acquisition of the pelvic region during 8xa0min (1-min frames) starting 1xa0min after i.v. injection of 4.07xa0MBq/kg/bw FCH which was followed immediately by a semi whole body acquisition.ResultsOverall, 262 lesions showed increased uptake on FCH-PET. Two hundred ten lesions (210/262) were interpreted as bone metastases. The mean standardized uptake values (SUV) in all malignant lesions was 8.1u2009±u20093.9. Forty-nine lesions (24%) had no detectable morphological changes on CT—probably due to bone marrow metastases. Fifty-six sclerotic lesions (having a Hounsfield unit (HU) level of more than 825) were interpreted as highly suspicious for metastatic bone disease on CT and/or other imaging modalities such as the bone scan but showed no FCH uptake. There was a significant correlation between tracer uptake as assessed by SUV and the density of sclerotic lesions by HU (ru2009=u2009−0.52, pu2009<u20090.001). The sensitivity, specificity, and accuracy of FCH-PET/CT in detecting bone metastases from prostate cancer was 79%, 97%, and 84%, respectively.ConclusionFCH-PET/CT showed promising results for the early detection of bone metastases in prostate cancer patients. We have found that a HU level of above 825 is associated with an absence of FCH uptake. Almost all of the FCH-negative sclerotic lesions were detected in patients who were under hormone therapy, which raises the possibility that these lesions might no longer be viable. However, clarification and the prognostic value of such lesions require further research.

Impact of 18F-Choline PET/CT in Prostate Cancer Patients with Biochemical Recurrence: Influence of Androgen Deprivation Therapy and Correlation with PSA Kinetics

We evaluated the potential of 18F-fluoromethyldimethyl-2-hydroxyethyl-ammonium (FCH) PET/CT in the detection of recurrent disease or distant metastases and correlated its diagnostic accuracy with prostate-specific antigen (PSA) levels in prostate cancer patients with biochemical evidence of recurrence. Furthermore, the influences of androgen deprivation therapy (ADT) and its duration on 18F-FCH PET were assessed in this study. Methods: This prospective study included 250 prostate cancer patients with PSA relapse who underwent 18F-FCH PET/CT. At the time of 18F-FCH PET/CT imaging, the mean PSA level was 46.9 ± 314.7 ng/mL and 55.2% (138/250) of patients were receiving ADT. Overall, ADT was performed on 67.2% (168/250) of patients after initial treatment. Imaging was performed on an integrated PET/CT system. Acquisition started 1 min after intravenous injection of 18F-FCH (4.07 MBq/kg of body weight) with dynamic PET images in the pelvic region during 8 min (1 min/frame) followed by a static semi–whole-body acquisition. The final diagnosis of positive PET lesions was based on histopathology or a consensus of clinical findings, additional imaging, or follow-up imaging modalities. Results: 18F-FCH PET/CT was able to correctly detect malignant lesions in 74% (185/250) of patients but was negative in 26% (65/250). In 28% of patients, only 1 lesion was detected (69/250); from these, 65.2% (45 patients) had a local recurrence, 18.8% (13 patients) a single lymph node, and 15.9% (11 patients) a solitary bone metastasis. The sensitivity of the 18F-FCH PET was significantly higher (P = 0.001) in patients with ongoing ADT (85%; confidence interval, 80%–91%) than in patients without ADT (59.5%; confidence interval, 50%–69%). 18F-FCH PET sensitivity was 77.5%, 80.7%, 85.2%, and 92.8% for the trigger PSA levels of more than 0.5, 1.0, 2.0, and 4.0 ng/mL, respectively. Scan sensitivity was 33% in patients with a trigger PSA level of less than 0.3 ng/mL and 77% in patients with a trigger PSA level of greater than 0.3 ng/mL, respectively (P = 0.001). Using a binary logistic regression analysis model, we showed trigger PSA and ADT to be the only significant predictors of positive PET findings. Conclusion: 18F-FCH PET/CT proved its potential as a noninvasive 1-stop diagnostic modality enabling us to correctly detect occult disease in 74% of patients and to differentiate localized from systemic disease. In patients with biochemical recurrence, it also guides to an optimal treatment approach after initial treatment. Trigger PSA and ADT are the 2 significant predictors of 18F-FCH–positive PET lesions. ADT seems not to impair 18F-FCH uptake in hormone-refractory prostate cancer patients.

The value of 18F-DOPA PET-CT in patients with medullary thyroid carcinoma: comparison with 18F-FDG PET-CT

The purpose of this prospective study was to compare the value of DOPA PET-CT with FDG PET-CT in the detection of malignant lesions in patients with medullary thyroid carcinoma (MTC). Twenty-six consecutive patients (10 men, 16 women, mean age 59u2009±u200914xa0years) with elevated calcitonin levels were evaluated in this prospective study. DOPA and FDG PET-CT modalities were performed within a maximum of 4xa0weeks (median 7xa0days) in all patients. The data were evaluated on a patient- and lesion-based analysis. The final diagnosis of positive PET lesions was based on histopathological findings and/or imaging follow-up studies (i.e., DOPA and/or FDG PET-CT) for at least 6xa0months (range 6–24xa0months). In 21 (21/26) patients at least one malignant lesion was detected by DOPA PET, while only 15 (15/26) patients showed abnormal FDG uptake. DOPA PET provided important additional information in the follow-up assessment in seven (27%) patients which changed the therapeutic management. The patient-based analysis of our data demonstrated a sensitivity of 81% for DOPA PET versus 58% for FDG PET, respectively. In four (4/26) postoperative patients DOPA and FDG PET-CT studies were negative in spite of elevated serum calcitonin and CEA levels as well as abnormal pentagastrin tests. Overall 59 pathological lesions with abnormal tracer uptake were seen on DOPA and/or FDG PET studies. In the final diagnosis 53 lesions proved to be malignant. DOPA PET correctly detected 94% (50/53) of malignant lesions, whereas only 62% (33/53) of malignant lesions were detected with FDG PET. DOPA PET-CT showed superior results to FDG PET-CT in the preoperative and follow-up assessment of MTC patients. Therefore, we recommend DOPA PET-CT as a one-stop diagnostic procedure to provide both functional and morphological data in order to select those patients who may benefit from (re-)operation with curative intent as well as guiding further surgical procedures.

The Use of F-18 Choline PET in the Assessment of Bone Metastases in Prostate Cancer: Correlation with Morphological Changes on CT (vol 11, pg 446, 2009)

Erratum to: The Use of F-18 Choline PET in the Assessment of Bone Metastases in Prostate Cancer: Correlation with Morphological Changes on CT Mohsen Beheshti, Reza Vali, Peter Waldenberger, Friedrich Fitz, Michael Nader, Josef Hammer, Wolfgang Loidl, Christian Pirich, Ignac Fogelman, Werner Langsteger Nuclear Medicine & Endocrinology, PET/CT Center Linz, St. Vincent’s Hospital, Linz, Austria Radiology, St. Vincent’s Hospital, Linz, Austria Radiation Oncology, St. Vincent’s Hospital, Linz, Austria Urology, St. Vincent’s Hospital, Linz, Austria Nuclear Medicine & Endocrinology, Paracelsus Private Medical University, Salzburg, Austria Division of Imaging, King’s College, London, UK