The role of volumetric and textural analysis of pretreatment 18F-fluorodeoxyglucose PET/computerized tomography images in predicting complete response to transarterial radioembolization in hepatocellular cancer.

OBJECTIVE: This study evaluates the role of pretreatment 18F-FDG PET/CT in predicting the response to treatment in patients with hepatocellular cancer (HCC) who applied transarterial radioembolization (TARE) via the volumetric and texture features extracted from 18F-FDG PET/CT images. METHODS: Thirty-three patients with HCC who had applied TARE [lobar (LT) or superselective (ST)] after 18F-FDG PET/CT were included in the study. Response to the treatment was evaluated from posttherapy magnetic resonance (MR). Patients were divided into two groups: the responder group (RG) (complete responders) and non-RG (NRG) (including partial response, stabile, and progressive). Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) and texture features were extracted from PET/CT images. The differences among MTV, TLG, and texture features between response groups were analyzed with the Mann-Whitney U test. ROC analysis was performed for features with P < 0.05. Spearman correlation analysis was used, and features with correlation coefficient < 0.8 were evaluated with the logistic regression analysis. RESULTS: Significant differences were detected in TLG, MTV, SHAPE_compacity, GLCM_correlation, GLRLM_GLNU, GLRLM_RLNU, NGLDM_coarseness, NGLDM_busyness, GLZLM_LZHGE, GLZLM_GLNU, and GLZLM_ZLNU between RG and NRG. Multivariate analysis demonstrated that MTV was the only meaningful parameter with an AUC of 0.827 (P = 0.002; 95% CI, 0.688-0.966). The best cutoff value was determined as 74.11 ml with 78.9% sensitivity and 78.6% specificity in discriminating nonresponders. CONCLUSION: In predicting the curative effect of TARE, multivariate analysis results demonstrated that MTV was the only independent predictor, and MTV higher than 74.11 ml were determined the best predictor of nonresponders.

The use of molecular volumetric parameters for the evaluation of Lu-177 PSMA I&T therapy response and survival.

PURPOSE: The primary aim of this study was to evaluate the volumetric therapy response via Ga-68 PSMA I&T PET/CT in patients treated with Lu-177 PSMA I&T therapy. The secondary purpose was to determine the impact of volumetric parameter responses to overall survival. METHODS: PSMA tumor volumes (PSMA-TV) and tumor lesion PSMA expressions (TL-PSMA) were calculated with a semi-automatic program on Ga-68 PSMA I&T PET/CT images that were obtained before and after Lu-177 PSMA I&T therapies with 19 patients. The median overall survival was compared with PSMA-TV, TL-PSMA, SUVmax, PSA, and alteration in PERCIST criteria. RESULTS: PSMA-TV values were decreased in 12 patients (63%), and TL-PSMA values were decreased in 15 patients (79%) following the therapy. The SUVmax and the PSA values were also decreased in 14 (74%) and 10 (53%) patients, respectively. The complete remission (CR) was observed in two patients (10%). The partial response (PR) and progressive disease were observed in 6 (32%) and 11 (58%) patients, respectively, according to PRECIST criteria. The survival rates were statistically significant in patients with a decrease in PSMA-TV and TL-PSMA values than patients without any decrease (p 0.001, p < 0.001, respectively). However, the survival rates did not differ in responders (PR or CR) and non-responders according to the PERCIST criteria (p 0.232). The survival rates did not also differ in responders and non-responders according to the SUVmax and PSA values (p 0.140, p 0.206, respectively). CONCLUSIONS: Molecular and volumetric parameters are beneficial in the assessment of Lu-177 PSMA I&T therapy response. Although the number of patients is small, TL-PSMA response, which includes both the tumor volume and PSMA expression in tumor, may be considered as the most valuable parameter for the evaluation of the therapy response and the prediction of survival rate.

The use of pre-test and post-test probability values as criteria before selecting patients to undergo coronary angiography in patients who have ischemic findings on myocardial perfusion scintigraphy.

OBJECTIVE: Myocardial perfusion scintigraphy (MPS) is a diagnostic test which is frequently used in the diagnosis of coronary heart disease (CHD). MPS is generally interpreted as ischemia present or absent; however, it has a power in predicting the disease, similar to other diagnostic tests. In this study, we aimed to assist in directing the high-risk patients to undergo coronary angiography (CA) primarily by evaluating patients without prior CHD history with pre-test and post-test probabilities. METHODS: The study was designed as a retrospective study. Between January 2008 and July 2011, 139 patients with positive MPS results and followed by CA recently (<6 months) were evaluated from patient files. Patients' pre-test probabilities based on the Diamond and Forrester method and the likelihood ratios that were obtained from the literature were used to calculate the patients' post exercise and post-MPS probabilities. Patients were evaluated in risk groups as low, intermediate, and high, and an ROC curve analysis was performed for the post-MPS probabilities. RESULTS: Coronary artery stenosis (CAS) was determined in 59 patients (42.4%). A significant difference was determined between the risk groups according to CAS, both for the pre-test and post-test probabilities (p<0.001, p=0.024). The ROC analysis provided a cut-off value of 80.4% for post- MPS probability in predicting CAS with 67.9% sensitivity and 77.8% specificity. CONCLUSION: When the post-MPS probability is ≥80% in patients who have reversible perfusion defects on MPS, we suggest interpreting the MPS as "high probability positive" to improve the selection of true-positive patients to undergo CA, and these patients should be primarily recommended CA.

Baker's Cyst on F-18 FDG PET/CT in a Patient with Ocular Melanoma.

UNLABELLED: We present the case of a 56-year-old man with the clinical diagnosis of ocular melanoma. As a part of staging, he underwent an F-18 FDG PET/CT scan for investigating distant metastasis. On PET scan, an increased focal area of F-18 FDG uptake was seen behind patient's right knee that can be confused with distant metastasis. On CT scan, there was a fluid density in the same location. The probable diagnosis was Baker's cyst. Later, USG and MRI confirmed this diagnosis. CONFLICT OF INTEREST: None declared.

The Effects of the Factors Related to the Patient and the Disease on the Performance of Ablation Therapy in Patients with Differentiated Thyroid Cancer who have Received I-131 Ablation Therapy.

OBJECTIVE: To investigate whether the factors related to the patient and the disease have any effect on the success of ablation therapy in patients with differentiated thyroid cancer who have received I-131 ablation therapy. MATERIAL AND METHODS: All the patients with differentiated thyroid cancer were referred for I-131 ablation therapy after thyroidectomy between July 2007 and September 2009. The patients had at least six months of follow-up. Age, gender, type of tumor, presence of capsule invasion, size of tumor, number of the tumors, localization of the tumor, invasion of thyroid capsule, lymph/vessel invasion, presence of metastatic lymph nodes, type of surgery, preablation values of thyroglobulin (Tg), AntiTg, TSH, surveys for the evaluation of metastatic disease, (thyroid and bone scintigraphy, neck and abdominal ultrasonography, chest and brain computerized tomography), administered dose, postablation I-131 whole body scan (WBS) and diagnostic I-131 WBS, neck USG, values of Tg and AntiTg at the 6th month were recorded. The presence of residual thyroid activity on the 6th month diagnostic I-131 WBS image was accepted as the criterion for ablation success. RESULTS: 191 patients with differentiated thyroid cancer were assessed in this study. The overall success rate of the first ablation therapy was 74.3%. The success rate of the ablation therapy was 66% and 75% in metastatic group and non-metastatic group, respectively. Except the significant correlation between the number of pathologic lymph nodes and the success of ablation (p=0.025), there was no other significant correlation between the patient/disease related factors and the success of ablation therapy. CONCLUSION: Significant correlation between the number of the pathologic lymph nodes and the ablation therapy performance can also be due to statistical error because of the limited sample size. There was no significant correlation between other patient/disease related prognostic factors and the success of ablation therapy. CONFLICT OF INTEREST: None declared.