Response evaluation of bone metastasis in prostate cancer: Preliminary comparison of computerized bone scan index versus standardized clinical criteria.

OBJECTIVE: The correlation between the computer-assisted bone scan index (BSI) responses versus clinical response classification if bone metastases in prostate cancer patients are not clear. We compared changes in BSI with Prostate Cancer Working Group-3 (PCWG3) and MD Anderson (MDA) criteria. MATERIALS AND METHODS: Fifty-six consecutive patients with at least two bone scans (BS) within 12 months were included, who had BS before and after treatment with the same anticancer agent. RESULTS: Progressive disease (PD) by PCWG3 criteria was seen in 28% of the cases (median BSI increased by 1.69 units) versus non-PD in 72% (BSI change -0.13). MDAnderson showed PD in 34% (BSI increase 0.49), 45% stable disease (BSI change 0.00), and 20% partial responses (BSI decrease 1.44). Absolute BSI changes differed significantly among response categories by PCWG3 and MDA criteria (both P<0.0001). Response classification using dichotomized BSI data (>0/≤0 and >0.3/≤0.3 BSI units) showed a significant correlation with PCWG3 and MDA criteria (all P<0.001). Absolute BSI changes and dichotomized BSI correlated to prostate-specific antigen responses (both P<0.001) but not to clinical responses. CONCLUSION: Absolute changes in BSI and BSI response classification correlated significantly with standardized clinical response criteria for the assessment of treatment responses of skeletal metastases in prostate cancer.

Incidental detection of colorectal lesions on 18 F-FDG-PET/CT is associated with high proportion of malignancy: A study in 549 patients.

Background and study aims Further diagnostics of incidental colorectal lesions on 18 F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is questionable. Therefore, we aimed to evaluate the clinical importance of incidentally detected colorectal lesions on FDG-PET/CT. Patients and methods In the North Denmark Region, a retrospective study was performed among 19,987 patients who had an FDG-PET/CT from January 2006 to December 2015. Among these patients, we identified patients with a colonoscopy within 12 months from the PET/CT scan and a description of incidental colorectal PET-avid lesions on the PET/CT. PET findings were compared with colonoscopy-detected lesions and eventually histopathology. Results Incidental PET-avid lesions were observed in 549 patients. Colonoscopy revealed lesions in 457 (83 %), among whom 338 patients had a final histopathological diagnosis. Malignant and premalignant lesions were found in 297 patients (54 % among patients with a PET-avid lesion). The lesions were cancer in 76 patients and adenoma in 221 patients of whom 30 had high-grade and 191 low-grade adenomas. The findings changed patient management in 166 cases (30 % of all patients with a PET-avid lesion). A colonoscopy-based surveillance program was initiated for 80 % of patients with high-grade adenoma. No patients with PET-avid lesions but normal colonoscopy developed colorectal cancer during 3 years of observation (median observation time 7 years). Conclusions Incidental colorectal FDG uptake was infrequently observed, but when present, it was associated with a high rate of malignant or premalignant lesions. Our results indicate that patients with incidental colorectal FDG uptake should be referred to diagnostic work-up including colonoscopy.

The Frequency of Focal Thyroid Incidental Findings and Risk of Malignancy Detected by 18F-Fluorodeoxyglucose Positron Emission Tomography in an Iodine Deficient Population.

Incidental focal uptake of 18F-fluorodeoxyglucose (FDG) in the thyroid on positron emission tomography (PET/CT) is rare but often associated with malignancy. The epidemiology of thyroid incidentalomas has only to some extent been described in countries with iodine deficiency. Here we report data from Denmark, a country with known iodine deficiency and wide access to PET/CT. All FDG PET/CT comprising the head and neck region, during 2014, were retrospectively reviewed, and patients with focal FDG uptake in the thyroid gland were identified. A total of 2451 patients had an FDG PET/CT of which 59 (2.4%) patients presented with FDG-avid focal lesions in the thyroid gland. Among the 59 patients with FDG-avid lesions, 33 patients (56%) received work up with ultrasound, thyroid technetium scintigraphy, fine needle aspiration, and/or histology of which 20 patients had a conclusive pathology report. Ten patients with FDG-avid lesions were identified with thyroid malignancy. The risk of thyroid malignancy was 16.9% among patient with incidental FDG-avid thyroid lesions. Our findings indicated a similar frequency of FDG thyroid incidentalomas and malignancy rates in an iodine deficient population compared to summary data from prior studies, studies mostly performed in geographical areas of normal or excess iodine supplementation.

Contrast-enhanced computed tomography does not improve the diagnostic value of parathyroid dual-phase MIBI SPECT/CT.

OBJECTIVE: The aim of this study was to investigate the contribution of contrast-enhanced computed tomography (CE-CT) to the localization of parathyroid adenomas compared with the dual-phase Tc-99m MIBI SPECT with low-dose CT (LD-CT). PATIENTS AND METHODS: This retrospective study included consecutive patients with primary hyperparathyroidism who underwent a preoperative dual-phase MIBI SPECT/CT followed by surgical resection. The standard of care was dual-phase MIBI SPECT/CT, acquired with LD-CT in the early phase and CE-CT in the late phase (SPECT/CE-CT). The presence and localization of positive sites were extracted from study reports. To examine the role of CE-CT, patient cases were independently re-reviewed, with the early LD-CT fused with early and late SPECT (SPECT/LD-CT). The two SPECT/CT methods were compared for sensitivity, and the positive predictive value and histopathology were used as a reference. RESULTS: In total, 138 patients were included. The investigation was positive for suspected adenomas in 124 patients using SPECT/CE-CT and in 122 patients using SPECT/LD-CT. The per-patient sensitivity was 87.5% [95% confidence interval (CI): 80.7-92.6%] for SPECT/CE-CT and was not statistically significantly different from SPECT/LD-CT (85.3%; 95% CI: 78.2-90.8%) (P=0.39). The positive predictive value was 95.2% (95% CI: 95.4-99.9%) with SPECT/CE-CT versus 100% (95% CI: 96.8-100%) with SPECT/LD-CT. For small adenomas (≤500 mg), the sensitivity was low with SPECT/CE-CT (67%) as well as with SPECT/LD-CT (64%). CONCLUSION: Late CE-CT, compared with late LD-CT, did not significantly improve the sensitivity of dual-phase Tc-99m MIBI parathyroid SPECT/CT in a population of patients with primary hyperparathyroidism. These findings were consistent regardless of the size, location, or histology of the adenomas.

Bone Scan Index Is an Independent Predictor of Time to Castration-resistant Prostate Cancer in Newly Diagnosed Prostate Cancer: A Prospective Study.

OBJECTIVE: To prospectively determine the prognostic value of the bone scan index (BSI) for time to development of castration-resistant prostate cancer (CRPC) in consecutive, hormone-naïve patients with newly diagnosed prostate cancer. PATIENTS AND METHODS: Eligible patients participated in a prospective, observational, multicenter study of the value of bone scintigraphy (BS) at staging. BSI was determined using the EXINI BoneBSI software in 208 consecutive patients undergoing androgen deprivation therapy. The presence or absence of bone metastases at staging was classified by BS with or without supplementary imaging. Follow-up was performed >5 years after including the last patient. RESULTS: During follow-up, 149 of the 208 patients (72%) were diagnosed with CRPC. Median time to CRPC was 20 months. Median follow-up time was 4.4 years in patients without CRPC. In univariate analyses, presence of bone metastases (M1) (hazard ratio [HR] 3.00, 95% confidence interval [CI] 2.10-4.30), Gleason grade (HR 1.53, 95% CI 1.31-1.79), and BSI (HR 1.17, 95% CI 1.12-1.23) but not PSA significantly predicted time to CRPC (all, P < .001). The predictive values of M1 (HR 2.06), Gleason grade (HR 1.47), and BSI (HR 1.10) were confirmed in multivariate analyses. Log-rank test for equality of time to CRPC showed the significant predictive value of BSI (BSI = 0 vs 0 < BSI ≤ 1 vs BSI > 1, P < .001). In addition to routine assessment of M1 vs M0 status, BSI contributed to the predictive power. CONCLUSIONS: BSI is an independent risk factor for the time from initiation of androgen deprivation therapy to CRPC in hormone-naïve patients. The significant prognostic factors, in rank order, were M1 status, Gleason grade, and BSI.

Diagnostic value of (18)F-FDG PET/CT as first choice in the detection of recurrent colorectal cancer due to rising CEA.

BACKGROUND: The diagnostic value of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) as the first imaging approach in the evaluation of rising carcinoembryonic antigen (CEA) is not clear. The objective of this study was to investigate the value of (18)F-FDG PET/CT in patients with colorectal cancer (CRC) and suspected recurrence based on rising CEA. METHODS: A total of 73 patients with CRC were referred to PET/CT after radical surgery. Generally, all patients were scheduled to follow a CT-based post-surgical follow-up regimen. In the case of rising CEA, (18)F-FDG PET/CT was performed in most patients with contrast-enhanced CT. The PET/CT images were independently reviewed by two readers. The presence or absence of recurrence was based on histology and/or standardized clinical follow-up. RESULTS: Among 35 patients who had confirmed recurrence of CRC, PET/CT demonstrated recurrence with a sensitivity of 85.7 %, a specificity of 94.7 %, a positive predictive value of 93.8 %, and a negative predictive value of 87.8 %. The SUVmax ranged from 1.3 to 19.9. The mean time since the last postoperative imaging and PET/CT was 8 months (median 4 months). CEA values at referral ranged from 1.5 to 164.0 µg/L (median 5.6 µg/L). The diagnostic properties of PET/CT were analyzed in subgroups of patients with a single rising CEA sample (30 patients, 41 %), 31 patients (43 %) with two or more consecutive increases, and 12 patients (16 %) with persistently elevated values. CONCLUSIONS: (18)F-FDG PET/contrast-enhanced CT has high diagnostic accuracy in the diagnosis of recurrent CRC, even in patients in a conventional CT-based follow-up program.

Calibration of sulfate levels in the archean ocean.

The size of the marine sulfate reservoir has grown through Earth's history, reflecting the accumulation of oxygen into the atmosphere. Sulfur isotope fractionation experiments on marine and freshwater sulfate reducers, together with the isotope record, imply that oceanic Archean sulfate concentrations were <200 microM, which is less than one-hundredth of present marine sulfate levels and one-fifth of what was previously thought. Such low sulfate concentrations were maintained by volcanic outgassing of SO2 gas, and severely suppressed sulfate reduction rates allowed for a carbon cycle dominated by methanogenesis.