Defining the optimal segmentation method for measuring somatostatin receptor expressing tumor volume on 68Ga-DOTATATE positron emission tomography/computed tomography to predict prognosis in patients with gastroenteropancreatic neuroendocrine tumors.

OBJECTIVE: We aimed to compare different segmentation methods used to calculate prognostically valuable volumetric parameters, somatostatin receptor expressing tumor volume (SRETV), and total lesion somatostatin receptor expression (TLSRE), measured by 68Ga-DOTATATE PET/CT and to find the optimal segmentation method to predict prognosis. PATIENTS AND METHODS: Images of 34 patients diagnosed with gastroenteropancreatic neuroendocrine tumor (GEPNET) who underwent 68Ga-DOTATATE PET/CT imaging were reanalyzed. Four different threshold-based methods (fixed relative threshold method, normal liver background threshold method, fixed absolute standardized uptake value (SUV) threshold method, and adaptive threshold method) were used to calculate SRETV and TLSRE values. SRETV of all lesions of a patient was summarized as whole body SRETV (WB-SRETV) and TLSRE of all lesions of a patient was computed as whole body TLSRE (WB-TLSRE). RESULTS: WB-SRETVs calculated with all segmentation methods were statistically significantly associated with progression-free survival except WB-SRETVat which was calculated using adaptive threshold method. The fixed relative threshold methods calculated by using 45% (WB-SRETV45%) and 60% (WB-SRETV60%) of the SUV value as threshold respectively, were found to have statistically significant highest prognostic value (C-index = 0.704, CI = 0.622-0.786, P = 0.007). Among WB-TLSRE parameters, WB-TLSRE35%, WB-TLSRE40%, and WB-TLSRE50% had the highest prognostic value (C-index = 0.689, CI = 0.604-0.774, P = 0.008). CONCLUSION: The fixed relative threshold method was found to be the most effective and easily applicable method to measure SRETV on pretreatment 68Ga-DOTATATE PET/CT to predict prognosis in GEPNET patients. WB-SRETV45% (cutoff value of 11.8 cm3) and WB-SRETV60% (cutoff value of 6.3 cm3) were found to be the strongest predictors of prognosis in GEPNET patients.

The evaluation of DLCO changes in patients with relatively higher lung shunt fractions receiving TARE.

OBJECTIVE: Transarterial radioembolization (TARE) with Yttrium-90 (90Y) labeled microspheres is an effective locoregional treatment option for patients with primary and metastatic liver cancer. However, TARE is also associated with radiation-induced lung injury due to hepatopulmonary shunting. If a large proportion of the injected radionuclide microspheres (more than 15%) is shunted, a rare but lethal complication may develop: radiation-induced pneumonitis (RP). Diffusion capacity of the lungs for carbon monoxide (DLCO) is a valuable test to assess lung function and a decrease in DLCO may indicate an impairment in gas exchange caused by the lung injury. Some previous researches have been reported the most consistent changes in pulmonary function tests after external beam radiotherapy are recorded with DLCO. This study aimed to examine the changes in DLCO after TARE with glass microspheres in newly treated and retreated patients with relatively higher lung shunt fractions. METHODS: We prospectively analyzed forty consecutive patients with liver malignancies who underwent lobar or superselective TARE with 90Y glass microspheres. DLCO tests were performed at baseline and on days 15, 30, and 60 after the treatment. All patients were followed up clinically and radiologically for the development of RP. RESULTS: A statistically significant decrease was found in the DLCO after the first treatment (81.4 ± 13.66 vs. 75.25 ± 13.22, p = 0.003). The frequency of the patients with impaired DLCO at baseline was significantly increased after the first treatment (37.5 vs 57.5% p < 0.05). In the retreated group (n = 8), neither the DLCO (71.5 ± 10.82 vs. 67.50 ± 11.24, p = 0.115) nor the frequency of patients with impaired DLCO (25 vs 25%, p = 1) did not significantly change. Also, the change in DLCO values did not significantly correlate with lung shunt fraction, administered radiation dose, and absorbed lung dose after the first and second treatments (p > 0.05 for all). None of the patients developed RP. CONCLUSION: Our study showed that a significant reduction in DLCO after TARE may occur in patients with relatively higher lung shunt fractions. Further studies with larger sample sizes are needed to better investigate the changes in DLCO in patients with high lung shunt fractions.

Comparison of WHO, RECIST 1.1, EORTC, and PERCIST criteria in the evaluation of treatment response in malignant solid tumors.

AIM: To compare response assessment according to the WHO, RECIST 1.1, EORTC, and PERCIST criteria in patients diagnosed with malignant solid tumors and who had received cytotoxic chemotherapy to establish the strength of agreement between each criterion. MATERIALS AND METHODS: Sixty patients with malignant solid tumors were included in this retrospective study. The baseline and the sequential follow-up fluorine-18-fluorodeoxyglucose PET/computed tomography (CT) of each patient were evaluated according to the WHO, RECIST 1.1, EORTC, and PERCIST criteria. PET/CT images were used for both metabolic and anatomic evaluation. The concurrent diagnostic CT and MRI images (performed within 1 week of PET/CT) were also utilized when needed. The results were compared using the κ-statistics. RESULTS: The response and progression rates according to the WHO criteria were 37 and 38%, respectively. The same ratios were also found for RECIST 1.1 (κ=1). The response and progression rates according to the EORTC criteria were 47 and 40%, respectively. When PERCIST criteria were used, one patient with progressive disease was upgraded to stable disease (κ=0.976). As we found the same results with WHO and RECIST 1.1 criteria, we used WHO criteria to compare the anatomic and metabolic criteria. When we compared the WHO and EORTC criteria, there was an agreement in 80% of the patients (κ=0.711). With WHO and PERCIST criteria, there was an agreement in 81.6% of the patients (κ=0.736). CONCLUSION: Significant agreement was detected when the WHO, RECIST 1.1, EORTC, and PERCIST criteria were compared both within as well as between each other.

The clinical utility of 99mTc-HMPAO SPECT in Fahr's disease.

Fahr's disease is a rare neurodegenerative syndrome, characterized by massive symmetrical intracerebral calcifications of the basal ganglia, dentate nuclei of the cerebellum, and the adjacent parenchyma. Computerized tomography (CT) is considerably more sensitive to detect these intracranial calcifications than other imaging modalities. The clinical, CT scan, and 99(m)Tc-D,L-hexamethylpropylene amine oxime (99(m)Tc-HMPAO) brain perfusion single-photon emission computerized tomography (SPECT) findings in a 42-year-old woman with Fahr's disease are reported, and the clinical utility of 99(m)Tc-HMPAO SPECT findings in Fahr's disease is discussed in this article. In conclusion, 99(m)Tc-HMPAO brain perfusion SPECT seems to be useful in the clinical approach to Fahr's disease, and may provide more specific and clinically relevant information when compared with anatomical imaging.

Multiparametric analysis of preoperative lymphatic mapping with the use of combined deep plus superficial radiotracer injection technique in early breast cancer.

OBJECTIVES: According to literature, combined tracer injection techniques seem to be the more powerful choice to eliminate technical and patient-related limitations. In this study, we analysed the quantitative performance parameters of combined deep plus superficial radiotracer injection and their correlation with a set of clinical, pathological and technical factors. METHODS: One hundred and sixteen women who underwent preoperative sentinel lymph node (SLN) mapping were studied prospectively. All patients received the simultaneous deep and superficial injection of 99mTc-nanocolloid. Mapping success rate, mean number of SLNs per patient and radiotracer uptake of SLNs were determined. The possible effects of age, tumour stage, laterality and location, type and time of previous biopsy, and SLN status on the quantitative parameters were analysed. RESULTS: Axillary SLNs were visualized in all cases. Mean number of axillary SLNs was 2.15 and advanced age (>50) significantly decreased the number of SLNs. Radiotracer uptake of SLNs was also significantly decreased by advanced age and a shorter time interval between biopsy and mapping (<10 days). Extra-axillary SLN visualization rates for medial, lateral and periareolar injection sites were 32%, 16% and 8%. Although SLN gamma probe counts were significantly higher in the single-day protocol, the 2-day protocol gave better contrast values which was also an important parameter in lesion detection. CONCLUSION: The combined radiotracer injection technique successfully demonstrated axillary and extra-axillary SLNs. Advanced age and previous biopsy time can lower the accuracy and reliability of SLN biopsy. Although periareolar injection gave the best results for the axilla, it was still insensitive for extra-axillary SLNs in spite of deep injection.

Simple provocative maneuvers in renal transplant scintigraphy for detecting urine leak.

Urine leak in the early postoperative period following renal transplantation is a serious complication requiring early identification and aggressive intervention, which significantly reduces the morbidity and mortality. Renal transplant scintigraphy is a noninvasive method to evaluate the perfusion and function of a transplanted kidney and urinary drainage including urine leak. Here, we reported two cases in which the standard transplant renogram failed to demonstrate urine leak. The cases were referred for a diethylenetriaminepentaacetic acid renogram following the transplantation to evaluate the cause of symptoms or elevated serum creatinine level. In both the cases, urine leak was successfully detected following simple maneuvers such as diuretic administration or Foley catheter irrigation. Renal transplant scintigraphy is an effective and safe technique and the use of these simple maneuvers can enhance the diagnostic sensitivity of the transplant renogram in the detection of urine leak.