Clinical value of fluorine-18-fluorodeoxyglucose PET/MRI for liver metastasis in colorectal cancer: a prospective study.

PURPOSE: To evaluate the diagnostic performance of liver 18F-FDG PET/MRI in addition to whole-body PET/CT and to compare it with MRI in the detection and clinical management of liver metastasis in patients with colorectal cancer (CRC). MATERIAL AND METHODS: Seventy-eight patients with CRC who underwent whole-body 18F-FDG PET/CT followed by liver PET/MRI were prospectively included. Histopathological confirmation and/or at least 3 months of clinical follow-up after PET/MRI were accepted as gold standard. Lesion and patient-based analyses were performed to evaluate the diagnostics performances of PET/CT, PET/MRI and MRI. In addition, changes of clinical management were evaluated. RESULTS: On lesion-based analysis, for PET/CT, PET/MRI and MRI; sensitivity (Se): 55.6%, 97.2% and 100%; specificity (Sp): 98.5%, 100% and 80.5%; and accuracy (Acc): 70.7%, 98.2% and 93.1% were calculated, respectively. Se and Acc of PET/MRI and MRI were significantly superior than PET/CT (P < 0.001). Se and Acc of PET/MRI and MRI were comparable; however, Sp of PET/MRI was significantly better than MRI (P < 0.001). On patient-based analysis, Se: 75.6%, 100% and 100%; Sp: 97.3%, 100% and 86.5%; and Acc: 85.9%, 100% and 93.5% were calculated, respectively. Se and Acc of PET/MRI were significantly superior than PET/CT (P < 0.001). Also, Se of MRI was significantly superior than PET/CT (P < 0.001). Se of PET/MRI and MRI were comparable, but Sp and Acc of PET/MRI were significantly better than MRI. The additional information obtained from liver PET/MRI changed treatment strategy in 14/78 (18%) patients compared to PET/CT or alone liver MRI. CONCLUSION: Diagnostic performances of PET/MRI and MRI for detection of CRC liver metastasis is superior to PET/CT. PET/MRI especially helps in the accurate detection of liver metastases that are suspicious on MRI and has the potential to change the clinical management of especially oligometastatic patients by identifying uncertain liver lesions.

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.

Evaluation of the relationship between muscle mass and serum myostatin levels in chronic hemodialysis patients.

The loss of muscle mass and cachexia is commonly seen in hemodialysis (HD) patients and contribute to morbidity and mortality. The exact mechanism of this fact is multifactorial and still unclear. Myostatin, a transforming growth factor-ß family ligand, is released from the skeletal and heart muscle and may be responsible for muscle degradation and atrophy. The aim of this study is evaluation of the relationship between muscle mass and serum myostatin level in chronic HD patients. One hundred and forty HD patients (79 males, 28 diabetic, mean age; 53.96 ± 13.6) were included in this cross-sectional study. Muscle mass measurement was made with dual energy-X ray absorptiometry. Appendicular skeletal muscle index (ASMI) was used as a muscle mass indicator. The anthropometric and biochemistry data were obtained. Serum myostatin levels were determined by an ELISA kit. Serum myostatin levels were elevated when compared to controls (P <0.001), but no significant correlation with ASMI was observed (P = 0.624). ASMI significantly correlated with serum creatinine (P <0.001), creatine phosphokinase (P <0.001), prealbumin (P <0.012), albumin (P <0.039), transferrin (P <0.001), phosphorus (P <0.001), Ca×P (P <0.012), inversely with Kt/V (P <0.001); not with BUN (P = 0.739), parathyroid hormone (P = 0.698), 25-hydroxyvitamin D (P = 0.603), bicarbonate (P = 0.062); such that these parameters also have influence on muscle mass regulation. Our study indicated that myostatin levels were high in HD patients but had no relation with ASMI. Myostatin is a well-known regulator of muscle mass so further studies are needed to demonstrate possible relationship.

Effect of the application of prophylactic central compartment lymph node dissectionon radioiodine ablation doses in patients with papillary thyroid carcinoma.

BACKGROUND/AIM: The aim of this study was to document the effect of the application of prophylactic central compartment dissection on radioiodine ablation activities for papillary thyroid carcinoma. MATERIALS AND METHODS: This retrospective study included 452 (383 females, 69 males; mean age = 46.69 years, min-max: 13-71) patients who received ablative radioiodine activity between April 2010 and December 2014. The histopathological reports of thyroidectomy and the administered radioiodine activity were evaluated. Frequencies of prophylactic central compartment dissection according to T stage of the primary tumor, detection rate of lymph node metastases, and its effect on radioiodine ablation activities were calculated. RESULTS: Prophylactic central compartment dissection was applied for a total of 252 (56%) patients. The T stages of these patients were T1a, T1b, T2, and T3 in 85 (34%), 106 (42%), 41 (16%), and 20 (8%) cases, respectively. The administered radioiodine ablation activity was affected by central compartment lymph node metastases in 112 (44%) patients. While 32 (29%) of these patients had papillary microcarcinoma (T1a), 48 (43%), 20 (18%), and 12 (11%) of them had T1b, T2, and T3 tumors, respectively. CONCLUSION: The application of prophylactic central compartment dissection affects the radioiodine ablation activity in approximately half of patients. This effect is more prominent in T1 stage tumors.

The Role of 18F-FDG PET/CT in the Primary Staging of Gastric Cancer.

OBJECTIVE: The aim of this study is to explore the role of 18F-FDG PET/CT in the primary staging of gastric cancer in the comparison of ceCT as routine staging method and evaluate influencing parameters of 18F-FDG uptake. METHODS: Thirty-one patients (mean age: 58.9±12.6) who underwent 18F-FDG PET/CT for primary staging of gastric cancer between June 2011 and June 2012 were included to the study. 18F-FDG PET/CT findings were compared with pathological reports in patients who underwent surgery following PET/CT. 18F-FDG PET/CT findings of primary lesions, lymph nodes and adjacent organs were compared with ceCT findings and pathological reports. Since 6 patients were accepted as inoperable according to 18F-FDG PET/CT and/or ceCT and/or laparotomy and/or laparoscopy findings, pathological confirmation could not be possible. RESULTS: In the postoperative TNM staging of patients, while 1 (4%), 1 (4%), 4 (16%), 2 (8%), 12 (48%) and 5 (20%) patients were staged as T0, Tis, T1, T2, T3 and T4, respectively, 8 (32%), 6 (24%), 6 (24%) and 5 (20%) patients were N0, N1, N2 and N3 respectively. 18F-FDG PET/CT was totally normal in 2 patients. While primary tumors were FDG avid in 27 patients, in 17 and 6 patients FDG uptake was observed in perigastric lymph nodes and distant organs, respectively. Mean SUVmax of FDG avid tumors was calculated as 13.49±9.29 (3.00-44.60). However, SUVmax of lymph nodes was computed as 9.28±6.92 (2.80-29.10). According to sub-analysis of histopathological subtypes of primary tumors, SUVmax of adenocarsinomas was calculated as 15.16 (3.00-44.60), of signet ring cells as 9.90 (5.50-17.70), of adenocarcinomas with signet ring cell component as 11.27 (6.20-13.90) (p=0.721). In the comparison with histopathological examination while ceCT was TP, TN, FN in 23, 1 and 1 patients, 18F-FDG PET/CT was TP, FP, FN in 20, 1 and 4 patients, respectively. Sensitivity, specificity, accuracy, PPD and NPV of ceCT in the detection of lymph node metastasis was calculated as 83.3%, 75%, 80%, 87.5% and 66.6%, respectively. These parameters for 18F-FDG PET/CT were 64.7%, 100%, 76%, 100% and 57.1%. CONCLUSION: Despite lower sensitivity than ceCT, diagnostic power of 18F-FDG PET/CT in the preoperative staging of gastric cancer is acceptable. Because of its high PPV, it might be beneficial in the evaluation of patients with suspected lymph nodes. The role of 18F-FDG PET/CT seems to be limited in the early stage and signet ring cell carcinomas due to lower 18F-FDG uptake.

The role of 18F-FDG PET/CT in detecting colorectal cancer recurrence in patients with elevated CEA levels.

INTRODUCTION: In this study we aimed to define the success of fluorine-18 (18F) fluorodeoxyglucose (FDG) PET/computed tomography (PET/CT) in detecting recurrent disease in our patient group with colorectal cancer (CRC) and elevated carcinoembryonic antigen (CEA) levels. MATERIAL AND METHOD: Patients who had a previous diagnosis of CRC were searched retrospectively in our PET center database. Seventy-six 18F-FDG PET/CT studies between October 2006 and December 2010 of 69 patients (25 women, 44 men; mean age: 61.61 ± 4.1 years) with elevated CEA levels were evaluated. 18F-FDG PET/CT findings and concurrent abdominopelvic contrast-enhanced computed tomography (ceCT) findings were compared with histopathological findings and/or clinical follow-up data as the 'gold standard'. RESULTS: In the patient-based analysis, the sensitivity and specificity of 18F-FDG PET/CT in the detection of disease recurrence were calculated as 97 and 61%, respectively. A statistically significant difference was found in frequencies of positive and negative 18F-FDG PET/CT findings between patients with or without recurrent disease by gold standard (P<0.05). There was no correlation between patients' serum CEA levels and lesions' maximum standardized uptake values (P=0.85). The sensitivity and specificity of ceCT were computed as 51 and 60%, respectively. In the evaluation of separate patient groups, although the sensitivity and specificity of 18F-FDG PET/CT were calculated as 100 and 60% in the group whose CEA level elevation was less than two-fold (5-9.9 ng/ml), these were 100 and 75% in the group with CEA elevation less than three-fold (10-14.9 ng/ml) and 95 and 62% in the group with elevation more than three-fold (≥ 15 ng/ml). The sensitivity and specificity of 18F-FDG PET/CT were computed as 98 and 85% in the lesion-based evaluation. The sensitivity and specificity of ceCT were 73 and 86%, respectively. CONCLUSION: 18F-FDG PET/CT is a safe imaging method that can be used in the determination of CRC recurrence in patients with elevated CEA levels, regardless of the CEA level.