Positioning irrigation of contrast cystography for diagnosis of occult vesicoureteric reflux: association with technetium-99m dimercaptosuccinic acid scans.

OBJECTIVE: Positioning irrigation of contrast (PIC) cystography identifies occult or PIC vesicoureteral reflux (PIC-VUR) in children with recurrent febrile urinary tract infections (UTI) but no vesicoureteric reflux (VUR) on standard voiding cystourethrogram (VCUG). We sought to identify the relationship between PIC-VUR and renal scarring in technetium-99m dimercaptosuccinic acid (DMSA) scans. PATIENTS AND METHODS: We retrospectively analysed PIC cystograms and DMSA scans for 154 kidneys in 81 children (65 girls; 16 boys; median age, 4.7 years; range, 0.9-15.2). Renal scarring was graded on a scale of 0-3. DMSA scans were pathologic in 66 patients (81%). Children had experienced mean 3.8 febrile UTI (range 1-25). Forty-seven (58%) children had a history of reflux, including 15 (19%) with previous anti-reflux operations. Indications for PIC cystography were recurrence of febrile UTI after either bilateral negative VCUG (66 children) or unilateral VUR (15 children) with contralateral/bilateral scarring or reflux that had changed sides in subsequent VCUGs. RESULTS: PIC-VUR was bilateral in 63, unilateral in 12, and absent in 6 children. Statistically significant associations between PIC-VUR grade and severity of renal scarring were identified in inter-individual (n = 77, p = 0.017) and intra-individual (refluxing vs. nonrefluxing kidney; n = 12, p = 0.008) analyses. After excluding patients with history of VUR, statistical significance was maintained in inter-individual analysis (n = 49; p = 0.018). CONCLUSION: The data suggest an association between PIC-VUR and severity of renal scarring, and legitimise the use of PIC cystography in children with renal scarring due to recurrent febrile UTI but negative findings on VCUG.

The use of F-18 choline PET in the assessment of bone metastases in prostate cancer: correlation with morphological changes on CT.

AIM: F-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. METHODS: Seventy 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 postoperative evaluation of suspected recurrence or progression based on clinical algorithms. PET imaging consisted of a dynamic PET/CT acquisition of the pelvic region during 8 min (1 min frames) starting 1 min after i.v. injection of 4.07 MBq/kg/bw FCH, which was followed immediately by a semi-whole body acquisition. RESULTS: Overall, 262 lesions showed increased uptake on FCH-PET. Two hundred ten lesions (210 of 262) were interpreted as bone metastases. The mean of maximum standardized uptake value (SUV(max)) in all malignant lesions was 8.1 +/- 3.9. 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 (r = -0.52, p < 0.001). The sensitivity, specificity, and accuracy of FCH-PET/CT in detecting bone metastases from prostate cancer was 79%, 97%, and 84%, respectively. CONCLUSION: FCH-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.

The use of F-18 choline PET in the assessment of bone metastases in prostate cancer: correlation with morphological changes on CT.

AIM: F-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. METHODS: Seventy 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 8 min (1-min frames) starting 1 min after i.v. injection of 4.07 MBq/kg/bw FCH which was followed immediately by a semi whole body acquisition. RESULTS: Overall, 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 8.1 +/- 3.9. 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 (r = -0.52, p < 0.001). The sensitivity, specificity, and accuracy of FCH-PET/CT in detecting bone metastases from prostate cancer was 79%, 97%, and 84%, respectively. CONCLUSION: FCH-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.

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

PURPOSE: The aim of this prospective study was to compare the potential value of (18)F fluorocholine (FCH) and (18)F fluoride positron emission tomography (PET)-CT scanning for the detection of bony metastases from prostate cancer. METHODS: Thirty-eight men (mean age, 69+/-8 years) with biopsy-proven prostate cancer underwent both imaging modalities within a maximum interval of 2 weeks. 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 (18)F FCH and (18)F 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 9.1 months. RESULTS: Overall, 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 (kappa=0.57), as well as in a patient-based analysis (kappa=0.76). Sixteen malignant sclerotic lesions with a high density were negative in both (18)F FCH and (18)F fluoride PET-CT [mean Hounsfield unit (HU), 1,148+/-364]. There was also a significant correlation between tracer intensity by SUV and density of sclerotic lesions by HU both in (18)F FCH PET-CT (r= -0.28, p < 0.006) and (18)F fluoride PET-CT (r= -0.20, p<0.05). The sensitivity, specificity and accuracy of PET-CT in the detection of bone metastases in prostate cancer was 81%, 93% and 86% for (18)F fluoride, and 74% (p=0.12), 99% (p=0.01) and 85% for FCH, respectively. (18)F 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. (18)F fluoride PET-CT identified more lesions in some patients when compared with (18)F FCH PET-CT but did not change patient management. CONCLUSION: FCH 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. (18)F fluoride) is recommended. (18)F fluoride PET-CT demonstrated a higher sensitivity than (18)F FCH PET-CT, but the difference was not statistically significant. Furthermore, (18)F 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.