Incidental Tc-99m MDP Uptake in Cortical-subcortical Parietotemporal Cerebral Area in a Patient with a History of Recent Ischemic Cerebrovascular Event who Underwent Whole-body Bone Scan.

The authors present Tc-99m methylene diphosphonate (MDP) uptake in the right parietotemporal area at whole-body bone scan (WBBS) in 75 years male patient with prostate adenocarcinoma Gleason score 3+4 (pT2N0Mx). No residual or metastatic disease was detected in the patient's Gallium-68 prostate-specific membrane antigen positron emission tomography/computed tomography four months before WBBS. The patient had undetectable prostate-specific antigen levels and underwent WBBS to restage prostate cancer due to equivocal findings in previous WBBS. Current WBBS planar views revealed heterogeneous Tc-99m MDP uptake in the right parietotemporal area and the sphenoid bone in addition to equivocal uptake on the lower lumbar vertebrae. Single-photon emission computed tomography study to identify the MDP-avid lesion on the right cranial area revealed heterogeneous Tc-99m MDP uptake in the right parietotemporal area and sphenoid bone. The patient had a history of transsphenoidal surgery for a hypophyseal tumor two years ago and a recent cerebrovascular event (CVE). Diffusion-weighted magnetic resonance imaging revealed a cortical-subcortical patchy area of restricted diffusion in the parietotemporal region compatible with acute ischemia. Heterogeneous Tc-99m MDP uptake in the right parietotemporal area was attributed to recent CVE and secondary vascular-tissue change-related dystrophic calcification.

The Role of 18F-FLT PET/CT in Assessing Early Response to Transarterial Radioembolization and Chemoembolization in Patients with Primary and Metastatic Liver Tumors.

Objectives: Metastases and primary malignancies are common in the liver. Local ablative applications such as transarterial chemoembolization (TACE), and transarterial radioembolization (TARE) provide minimally invasive and safe treatment in unresectable liver tumors. Early detection of response to treatment prevents unnecessary toxicity and cost in non-responder patients and provides an earlier use of other options that may be effective. This study aimed to identify the role of 18F-fluorothymidine (FLT) positron emission tomography/computed tomography (PET/CT) in the assessment of early response to TACE and TARE treatments in patients with unresectable primary and metastatic liver tumors. Methods: This single-center study included 63 patients who underwent 18F-FLT PET/CT for response evaluation after TACE and TARE. After excluding 20 patients whose data were missing 43 TARE-receiving patients were analyzed. The compatibility of change in semi-quantitative values obtained from the 18F-FLT PET/CT images with the treatment responses detected in 18F-fluorodeoxyglucose PET/CT, CT, and MR images and survival was evaluated. Results: There was no correlation between early metabolic, morphological response, and 18F-FLT uptake pattern, and change in standardized uptake values (SUV) which were ΔSUVmax, ΔSUVmean, ΔSUVpeak., ΔSUVmean, Δ SUVpeak values. There was no significant correlation between 18F-FLT uptake pattern, ΔSUVmax, ΔSUVmean, ΔSUVpeak, and overall survival, progression-free survival (PFS) for the target lobe PFS for the whole-body. The survival distributions for the patients with >30% change in Δ SUVmax and ΔSUVpeak values were statistically significantly longer than the patients with <30% change (p<0.009 and p<0.024, respectively). Conclusion: There was significant longer PFS for target liver lobe in patients with more than 30% decrease in 18F-FLT SUVmax and SUVpeak of the liver lesion in primary and metastatic unresectable liver tumors undergoing TARE.

Prognostic value of metabolic parameters on baseline 18F-FDG PET/CT in small cell lung cancer.

BACKGROUND: Maximum standardized uptake value (SUVmax) is the primary quantitave parameter given in 18F-FDG PET/CT reports. Calculations derived from three dimensional metabolic volumetric images have been proposed to be more successful than SUVmax alone in prognostification with a lower interobserver variability in many cancers. We aimed to determine the prognostic value of metabolic parameters derived from 18F-FDG PET/CT studies in small cell lung cancer (SCLC) patient population with a long follow-up time. METHODS: In this study, 38 consecutive SCLC patients (34M, 4F, age:65.76 ±8.18 years) who were referred to 18F-FDG PET/CT for staging between October 2006-January 2011 were included. SUVmax, SUVmean, SUVpeak, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were calculated. Overall survival (OS) was calculated from the date of the initial PET/CT to death from any cause. Survival tables were obtained and Kaplan Meier curves were reconstructed. Mantel-Cox regression analysis was performed in order to investigate if any of these parameters have an effect on survival along with other clinical risk factors. RESULTS: Median SUVmax, SUVmean, SUVpeak, MTV, TLG and LDH values were calculated as 13.9 g/dL, 6.4 g/dL,10.69 g/dL, 147 cm3, 1898.52 and 375U/L respectively. Median follow-up was 761.23±873.21 days (25.37 months, range:110-3338 days). Since basal 18F-FDG PET/CT scans, all patients were lost in the follow-up except for two patients. MTV was a significant prognostic factor in SCLC patients. Estimated mean survival times were 261.0±45.6 (95% CI: 171.6-350.3) days in patients with MTV value above the calculated median 147, and 577.0±124.0 (95% CI: 333.7-820.2) days in patients with MTV<147. The difference was statistically significant with a P=0.037. CONCLUSIONS: Baseline whole body MTV reflecting total tumor load is a prognostic index in SCLC. SUV is insufficient to predict prognosis.

Detectability of 18F-choline PET/MR in primary hyperparathyroidism.

PURPOSE: We aimed to evaluate the power of 18F-fluorocholine (FCH) positron emission tomography/magnetic resonance (PET/MR) imaging in unlocalized primary hyperparathyroidism. METHODS: Thirty-four patients were included. In 17/34 patients, PET/MR was performed immediately after a negative 18F-FCH PET/CT. Sensitivity, specificity, positive and negative predictive values were calculated for MR only (blinded to PET data) and PET only (blinded to MR data) findings. RESULTS: 18F-FCH PET/MR was positive in 26/34 (76%) patients. PET/MR was also positive in 12/17 (71%) patients with a negative PET/CT. Among 11/34 (32%) patients where 18F-FCH PET-only and MR-only results were discordant, MR was false positive in 7/11 patients (3/7 of the lesions were not 18F-FCH avid and in 4/7 of them PET and MRI pointed different locations. Postoperative histopathology revealed that 18F-FCH-positive ones were true positives). Sensitivity, specificity, PPV, NPV and accuracy of neck MR evaluated blinded to PET data were 80%, 50%, 70%, 64% and 68%, respectively, and all were calculated as 100% for PET/MR. CONCLUSION: 18F-FCH PET/MR is very effective in preoperative localization of parathyroid adenomas even if 18F-FCH PET/CT is negative. Neck MR alone is insufficient in detecting parathyroid adenomas but PET/MR combination helps in precise localisation.

Prognostic importance of prostatic specific antigen response in patients who received Lutetium-177 prostate-specific membrane antigen treatment for castration resistant prostate cancer.

BACKGROUND: This study aims to analyze the prognostic importance of serum prostate specific antigen (PSA) response in patients who received radioligand therapy (RLT) with Lu-177 Prostate-specific membrane antigen (PSMA) for their castration-resistant prostate cancer. METHODS: Thirty consecutive patients who received Lu-177 PSMA treatment for their castration-resistant prostate carcinoma were included. All the patients had undergone Ga-68 PSMA PET/CT scanning before Lu-177 PSMA therapy, which revealed multiple metastases. Patients were treated with a fixed dose (180 mCi) of Lu-177 PSMA at six to eight weeks intervals. PSA response was evaluated using Prostate Cancer Working Group 3 (PCWG3) criteria. Serum PSA response was classified as PSA progression (25% increase over the baseline and an increase in the absolute-value PSA level by at least 5 ng per millilitre), any <50% decline or ≥50% decline. PSA response was evaluated six weeks after every cycle. Response evaluation with radiological imaging and Ga-68 PSMA PET/CT were performed before the first cycle and eight weeks after the last cycle. RESULTS: Thirty patients were treated with a total of 171 cycles (median 4, range 3-7) of Lu-177 PSMA. A decline in serum PSA of ≥50% was detected in ten patients (33%) while a decline in PSA of any amount was observed in fifteen (50%) patients after the first cycle. After the last cycle, a decline in PSA ≥50% and of any amount was seen in thirteen (43%) and fourteen (46%) patients, respectively. Of the fifteen patients who were not responder after the first cycle, three (20%) had a decline in PSA of any amount after the completion of the RLT. Moreover, of the 20 patients who did not have a ≥50% decline in PSA level after the first cycle, four (20%) became responder after the last cycle. Regarding serum PSA response after the first cycle, median OS was significantly higher for patients who had ≥50% decline in PSA level with 21.0±10.0 (95% CI: 1.2-40.7) months compared to patients who had not with 8.0±2.6 (95% CI: 2.7-13.2) months (P=0.012). A decline in PSA of any amount after the first cycle did not have a significant impact on median OS (12.0±1.1 vs. 6.0±2.5 months, P=0.08). The decline in serum PSA level after the last cycle of treatment had a significant impact on OS. Median OS for the decline in PSA of any amount was calculated as 13.0±1.0 (95% CI: 10.9-15.0) months for responders and 6.0±1.9 (95% CI: 2.2-9.7) months for non-responders (P=0.016). Considering ≥50% of decline as a response, median OS was 21.0±5.8 (95% CI: 9.5-32.4) months for responders and 6.0±3.0 (95% CI: 0.1-11.8) months for non-responders (P=0.026). CONCLUSIONS: Serum PSA level during RLT with Lu-177 PSMA remains a clinically significant factor to predict OS times. About twenty percent of patients who were not responder after the first cycle could become responder after the last cycle. However, patients without PSA response after completion of all cycles should be closely followed-up. Non-responder patients can achieve a response with further treatments.

Role of Thyroglobulin Doubling Time in Differentiated Thyroid Cancer and Its Relationship with Demographic-Histopathologic Risk Factors and 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Parameters.

Background: Aim of this study was to investigate the relationship between thyroglobulin doubling time (TgDT) and basal risk factors and metabolic parameters derived from 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in differentiated thyroid cancer (DTC). Materials and Methods: An analysis of 95 DTC patients who had rising serum thyroglobulin (Tg) levels under levothyroxine (LT4) suppression after radioiodine therapy was made. TgDT was calculated for 28/95 patients. The relationship between TgDT and basal demographic and histopathologic risk factors, preablative Tg, and antithyroglobulin antibody (ATg) levels and metabolic parameters was analyzed. Results: In 28 patients (15M, 13F, mean age: 52.6 ± 17.6) that TgDT could be calculated, 18F-FDG PET/CT was positive in 12 patients. Median TgDT was lower in 18F-FDG PET/CT positive patients compared to the negative cases (p < 0.05). Patients with skeletal metastasis or local recurrence had a shorter DT compared to the patients with lung metastasis. TgDT was correlated with peak standardized uptake value (SUVpeak) (p < 0.05). Maximum standardized uptake value (SUVmax) was correlated with tumor size (p < 0.05) and mean standardized uptake value (SUVmean) with tumor size and vascular invasion (p < 0.05). Median SUVmax and SUVmean were higher in follicular cancer or poor histological variants of papillary DTC compared to papillary cancer classical variant patients Conclusion: TgDT may be predictive of a positive 18F-FDG PET/CT in DTC. Skeletal metastasis and local recurrence are related to shorter TgDT. Greater tumor size, vascular invasion, and follicular cancer or poor variants of papillary carcinoma are related with higher SUVmax and SUVmean. Larger scale studies are needed to confirm results and to calculate a possible cutoff of TgDT for a positive 18F-FDG PET/CT study.

Analysis of prognostic factors in patients receiving transarterial radioembolization for unresectable hepatocellular carcinoma.

AIM: This study aimed to analyze the prognostic factors of patients receiving transarterial radioembolization for unresectable hepatocellular carcinoma. MATERIAL AND METHOD: Eighty-six (73 M and 13F; mean age: 64.3 ± 9.8 years) patients who received transarterial radioembolization for unresectable hepatocellular carcinoma were included. Relationship between serum alpha-fetoprotein and international normalization ratio level, albumin-bilirubin grade, neutrophil-lymphocyte ratio, presence of portal venous thrombosis and extrahepatic metastases, the dimension of index lesion and OS were analyzed. RESULTS: Neutrophil lymphocyte ratio was ≤ 5 in 76 (88%) and >5 in 10 (12%) of patients. Sixty-two (72%) patients died during a mean of 25.6± 9.7 months follow-up. Mean OS for all patients was calculated as 12.9 ± 14.6 months. In univariate analysis, albumin-bilirubin grade (22.3 ± 3.8 vs. 11.6 ± 4.2; P = 0.03), neutrophil-lymphocyte ratio (21.8 ± 3.6 vs. 7.3 ± 2.6; P =0.04), presence of extrahepatic metastases (30.1 ± 5.4 vs. 7.4 ± 2.0; P = 0.001) and portal venous thrombosis (26.5± 4.8 vs. 10.5 ± 2.1; P = 0.01) had significant effect on OS. In multivariate analysis, serum international normalization ratio (P = 0.005) and alpha-fetoprotein level (P = 0.004), albumin-bilirubin grade (P = 0.05), neutrophil-lymphocyte ratio (P = 0.007), Child-Pugh score (0.006) and presence of ascites (P = 0.005) were significantly correlated with OS. CONCLUSION: Patients with low basal albumin-bilirubin grade and neutrophil-lymphocyte ratio survive longer after transarterial radioembolization for unresectable hepatocellular carcinoma. Presence of extrahepatic metastases and portal venous thrombosis seems to have a prognostic value.

Predictor of 68Ga PSMA PET/CT positivity in patients with prostate cancer.

BACKGROUND: The aim of this study was to evaluate predictive factors of 68Gallium (68Ga) prostate-specific membrane antigen (PSMA) positron emission tomography (PET)/computed tomography (CT) positivity. METHODS: Relationships between serum prostate specific antigen (PSA), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) levels, Gleason Score (GS) and positivity of 68Ga PSMA PET in patients who underwent 68Ga PSMA PET/CT for restaging for PCa were evaluated retrospectively. RESULTS: One hundred and four (median age: 67; range: 51-88) patients were included in this study. Of these patients, PSMA PET was positive in 75 (72%) patients. Mean serum PSA levels for PET negative and positive groups were 0.76±1.00 and 180.85±324.93 ng/mL (P<0.001). The sensitivity and specificity of 68Ga PSMA PET/CT for detection of disease recurrence were calculated as 92% and 80%, respectively, for the 1.4 ng/mL PSA cut-off and 92% and 90%, respectively, for the 2 ng/mL PSA cut-off values. The positivity rates for patients with PSA levels <1.4 ng/mL and ≥1.4 ng/mL were 21% and 90%, respectively (P<0.001). CONCLUSIONS: 68Ga PSMA PET/CT seems to be a highly sensitive in patients with early PSA recurrence. Patients with higher GS and early PSA recurrence could benefit from 68Ga PSMA PET/CT.

Comparison of bone scintigraphy and Ga-68 prostate-specific membrane antigen positron emission tomography/computed tomography in the detection of bone metastases of prostate carcinoma.

AIM: This study aims to assess the diagnostic performance of Ga-68 prostate-specific membrane antigen PET/computed tomography in the comparison of planar bone scintigraphy in the detection of bone metastases. Another purpose is to define the additional benefit of bone scintigraphy subsequent to prostate-specific membrane antigen PET/computed tomography and the role of prostate-specific membrane antigen PET/computed tomography in the treatment planning. MATERIAL AND METHOD: Forty-six patients with a median interval of 19 (range: 3-90) days between prostate-specific membrane antigen PET/computed tomography and bone scintigraphy included in the analysis. Diagnostic performance of both modalities was calculated and compared. RESULTS: Prostate-specific membrane antigen PET/computed tomography and bone scintigraphy were performed for initial staging in 25 (54%), for evaluation of biochemical recurrence in 11 (24%) and metastatic castration-resistant prostate carcinoma in 10 (22%) patients. In the patient-based analysis sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for bone scintigraphy for detection of bone metastases were calculated as 50%, 19-29%, 32-39%, 32-39%, and 33-39%, respectively, based on whether equivocal findings were classified as positive or negative. For prostate-specific membrane antigen PET/computed tomography, these values were found significantly higher as 100%, 95-100%, 98-100%, 96-100%, and 100%, respectively. The diagnostic performance of bone scintigraphy and PET/computed tomography in clinical subgroups was analyzed, prostate-specific membrane antigen PET/computed tomography was superior to bone scintigraphy in three groups. CONCLUSION: In this retrospective study, prostate-specific membrane antigen PET/computed tomography was found to be superior to planar bone scintigraphy in the detection of bone metastases. Additional bone scintigraphy seems to be unnecessary in patients who underwent prostate-specific membrane antigen PET/computed tomography within three months period without additional treatment.

18F-Flourodeoxy glucose PET-computed tomography in testicular carcinoma: diagnostic and prognostic value.

AIM: This study aims to assess the diagnostic role of F-FDG PET/computed tomography in primary staging and restaging of testicular cancer in comparison with contrast-enhanced diagnostic thoracic-abdominopelvic computed tomography. MATERIAL AND METHOD: Thirty-two consecutive male patients with testicular carcinoma (median age: 29, min-max: 17-65) who were referred to the nuclear medicine department for F-FDG PET/computed tomography were retrospectively included in the study. Patients were evaluated based on the F-FDG PET/computed tomography indications and germ cell tumor subtypes. RESULTS: On patient-based analysis, overall sensitivity, specificity, PPV, NPV and accuracy of 18F-FDG PET/computed tomography were 71%, 100%, 100%, 30% and 75%. On lesion-based analysis, for evaluation of lymph node metastasis they were 76%, 100%, 100%, 57% and 81%, and for detection of distant metastasis 85%, 100%, 100%, 90% and 93%, respectively. Median SUVmax for seminomas were calculated as 14.2 and for nonseminomas 7.8 (P = 0.62) Mean time to progression and overall survival were calculated as 76.6 ± 10.7 and 111 ± 7.5 months, respectively. Mean overall survival and time to progression for PET-positive and negative groups was not found significant (P = 0.69 and P = 0.81). The only significant factor in predict overall survival was the presence of distant organ metastases in PET/computed tomography (124.6 ± 5.2 vs. 78.7 ± 14.0 months, P = 0.02). CONCLUSION: In this single-center experience with a limited number of patients, F-FDG PET/computed tomography appears to have a value of staging and restaging for both seminomatous and non-seminomatous GCTs.

68Ga-DOTATATE Uptake in Pancreatic Metastasis of Renal Cell Carcinoma Mimicking Pancreatic Neuroendocrine Tumor.

A 61-year-old man, with a history of prior clear cell renal cell carcinoma in remission, was referred to Ga-DOTATATE PET/CT for the further evaluation of pancreatic tail mass. Ga-DOTATATE PET/CT showed pathologically intense uptake on the pancreatic mass; subsequent biopsy of the pancreatic mass confirmed the diagnosis of clear cell renal cell carcinoma metastasis. Ga-DOTATATE uptake is not specific for neuroendocrine tumors. In the presence of prior malignancy, it should be kept in mind that malignancies apart from neuroendocrine tumors express somatostatin receptors, and they can show Ga-DOTATATE uptake.

Risk Factors for Predicting Osteoporosis in Patients Who Receive Thyrotropin Suppressive Levothyroxine Treatment for Differentiated Thyroid Carcinoma

Objectives: Endogenous hyperthyroidism accelerates bone turnover and shortens the normal bone remodeling cycle, which results in reduced bone density. It is estimated that suppressive levothyroxine (LT4) therapy also decreases bone density. The aim of this study was to define risk factors for osteoporosis development in patients under thyrotropin-stimulating hormone (TSH) suppressive treatment for differentiated thyroid cancer (DTC). Methods: Patients with a diagnosis of low or intermediate risk group DTC according to the American Thyroid Association 2015 guidelines and who have been receiving LT4 suppression therapy and were physically fit to undergo femur and lumbar vertebra bone density study were included in the study. Patients lacking information on demographic data, medical history, preoperative thyroid hormone status, or routine follow-up data were excluded from the study. A study form consisting of patient information on possible risk factors for osteoporosis such as gender, age, menopausal status, smoking, family history of osteoporosis, preoperative thyroid hormone status, postoperative hypoparathyroidism history, mean serum TSH levels, and duration of TSH suppression was created and filled out for each participant. Bone mineral densitometries of the femur and lumbar vertebrae were measured along with serum vitamin D and parathyroid hormone levels. Results: During TSH suppression (mean 7.2±4.5 years, range: 1-26), osteoporosis was detected in 89 (9.6%) patients. The mean time to develop osteoporosis was significantly different in patients with or without a family history of osteoporosis (15.3±0.4 versus 20.3±0.6 years; p=0.002). Similarly, the mean time to develop osteoporosis for was found to be significantly shorter in postmenopausal patients than that for premenopausal women (18.6±0.7 versus 20.4±0.4 years; p<0.001). Male gender (p<0.001), a family history of osteoporosis (p=0.001) and menopausal state (p<0.001) were identified as independent predictive factors for developing osteoporosis. Conclusion: Postmenopausal women, men, and patients with a family history who receive TSH-suppression treatment have a tendency to develop osteoporosis.

Dynamic risk stratification for predicting the recurrence in differentiated thyroid cancer.

AIM: To analyze the predictive value of the dynamic risk stratification (DRS) system for assessing the risk of recurrent/persistent disease in our large group of differentiated thyroid carcinoma (DTC) patients. PATIENTS AND METHODS: We retrospectively included 2184 consecutive patients who received radioiodine ablation therapy following a total or near total thyroidectomy in our department between 1998 and 2014. The American Thyroid Association (ATA) classification was used for initial risk classification. At the second year of follow-up period after radioiodine ablation therapy, DRS was performed also. The ATA and DRS risk classification results were compared with clinical outcome. RESULTS: According to DRS, more than half of the ATA high-risk patients (73.2%) moved to the DRS low-risk category and the 6.4% of ATA low-risk patients comprised the DRS high-risk category. In comparison of variables within the ATA and the DRS risk groups with clinical outcome, combined use of the ATA and the DRS systems was statistically significant to predict the recurrent/persistent disease (P<0.005). CONCLUSION: The present study revealed that the DRS system is a necessary stratification system in addition to the initial risk evaluation. The DRS can discriminate those patients who does not require closer follow-up in the long-term period.