Eser Kaya

TC-99m MIBI spect imaging in patients with lung carcinoma : Is it a functional probe of multidrug resistance genes?

Objective: Multidrug-resistance (MDR) phenotype concerns altered membrane transport that results in lower cell concentrations of cytotoxic drug in many cancer types, including lung cancer, and is related to the overexpression of a variety of proteins that act as adenosine triphosphate-dependent extrusion pumps. Tc-99m Sestamibi (MIBI) is a transport substrate for P-glycoprotein (Pgp) pump. In this study, we assessed the uptake and clearance of technetium-99m-2-hexakis 2-methoxyisobutylisonitrile (Tc-99m MIBI) from the tumor and its correlation with messenger RNA (mRNA) levels of Pgp, MDR-associated protein (MRP1), and lung resistance protein (LRP) in lung carcinoma. Methods: This study was carried out on 19 patients (mean age, 60.1 ± 2.07 years) with advanced-stage lung carcinoma. The tumor samples obtained by bronchoscopy were assessed to estimate the levels of Pgp, MRP1, and LRP expression on mRNA level by quantitative real-time reverse-transcription polymerase chain reaction. Tc-99m MIBI chest imaging was performed 15 and 180 minutes after injection of 740 MBq Tc-99m MIBI. The early (T/Be) and delayed (T/Bd) Tc-99m MIBI uptakes and washout rate (WR) of Tc-99m MIBI from the tumor were measured. Results: No correlation was found between the T/Be Tc-99m MIBI uptake of tumors (T/Be) and the levels of Pgp mRNA, MRP1 mRNA, and LRP mRNA by reverse-transcription polymerase chain reaction. There was a correlation between the mean T/Bd Tc-99m MIBI uptake and Pgp expression of the tumors (P = 0.001, Spearman ρ = − 0.702). There was a correlation between the WR of Tc-99m MIBI from the tumor and Pgp expression of the tumor (P = 0.000, Spearman ρ = 0.875). Washout rate of Tc-99m MIBI was not related to the levels of MRP1 mRNA (P = 0.93, Spearman ρ = 0.02) or LRP mRNA (P = 0.47, Spearman ρ = 0.177). Conclusions: Increased WR of Tc-99m MIBI is related in Pgp over expression of the tumor. Tc-99m MIBI single photon emission computed tomography imaging may be a functional probe of overexpression of Pgp in patients with lung carcinoma. However, Tc-99m MIBI single photon emission computed tomography imaging cannot be used to identify the MDR involved in the MRP1 or LRP in these patients.

No apparent correlation between Behcet's disease and oxidative stress disturbance

UNLABELLED Behçets disease (BD) is a chronic, progressive and inflammatory multisystemic disease, that significantly affects the cardiovascular system. Oxidative stress (OS) is a disturbance in oxidant/antioxidant balance in favor of oxidants. The OS that increases acutely and chronically due to the inflammatory process plays an important role in the pathogenesis of the cardiovascular system effects of the disease by causing endothelial dysfunction in vascular structures. The aim of our study was to investigate the relationship between OS and myocardial perfusion, which is based on microvascular dysfunction, in BD. MATERIAL AND METHOD Twenty-seven patients with BD (16 M, 11 F, mean age: 38.7 +/- 9.4 years) and 22 healthy volunteers (12 M, 10 F, mean age: 35.8 +/- 6.5 years) participated in our study. Technetium-99m methoxyisobutylisonitrile single photon emission computed tomography (Tc-99m MIBI SPECT) stress-rest test was performed with two-day protocol. Myocardial perfusion scores (summed stress score, summed rest score, summed difference score, fix defect score) and perfusion defect prevalence (stress, rest, ischemic and fixed) were determined as the percentage of left ventricle. Coronary angiography was performed in patients with abnormal myocardial perfusion scintigraphy. For OS analysis, the blood samples were taken immediately before the first imaging procedure and were studied for malondialdehyde, glutathione, nitrite, nitrate, vitamin C, retinol, and carotene. RESULTS In the BD group, a total of 9 patients had abnormal findings in their stress and rest electrocardiography. Perfusion defect in myocardial perfusion scintigraphy was observed in 14 patients (51.8%). Twelve patients accepted coronary angiography, and their results were normal. In the comparison of myocardial perfusion scores, perfusion defect prevalence and OS parameters, there was a significant difference between the BD and control groups. In the BD group, no correlation was observed between myocardial perfusion scores, perfusion defect prevalence and OS parameters. CONCLUSION Defects in myocardial perfusion and increase in OS were observed in BD; however, there was no correlation between the two findings in the inactive period. In other words, the prevalence and intensity of myocardial perfusion defects can vary at different OS levels.

Colonic Malignant Melanoma: 18 F-FDG PET/CT Findings

Primary malignant melanoma occurs most often in the skin and much less frequently in the choroid layer of the eyes, in the leptomeninges, oral cavity, nasal mucosa, pharynx, esophagus, bronchus, under the nail and vaginal or anorectal mucosa. Primary melanoma of the gastrointestinal tract has been confirmed for lesions occurring in the esophagus, stomach, small bowel, and anorectum through several published reports, as these are the areas where melanocytes normally exist. The occurrence of primary malignant melanoma in the colon is relatively rare, because melanocytes are embryologically absent in the large bowel. Herein we report a patient whose colonic malignant melanoma was diagnosed and disseminated metastatic lesions were revealed with 18F-FDG PET/CT scan. There were multiple nodular lesions showing increased 18F-FDG uptake in both lungs. There was a soft tissue lesion with slightly increased 18F-FDG uptake, which extended to the intraluminal region of the thoracic esophagus. Increased metabolic activity was detected in the asymmetric stomach wall thickening site and in a soft tissue lesion located on the gall bladder wall that was filling the lumen. Multiple hypodense/hyper-metabolic lesions were identified in the liver. Multiple hyper-metabolic polypoid soft tissue lesions were visualized in almost the entire colonic segments. Multiple hyper-metabolic peritoneal implants were noted in all abdominal quadrants. Increased 18F-FDG uptake was detected at the right surrenal gland soft tissue lesion. There was a hyper-metabolic soft tissue lesion on the posterior wall of the rectum. Hyper-metabolic lytic lesions were seen at the thoracal and lumbar vertebrae, left scapula, left iliac bone, sacrum and left femur. There was no evidence of 18F-FDG avid skin lesions in both attenuation corrected and non-corrected images.

Comparison of lung tumor segmentation methods on PET images

Lung cancer is the most common cause of cancer-related deaths that occur all over the world. Recently, various image processing approaches have been used on PET images in order to characterize the uniformity, density, coarseness, roughness, and regularity (i.e., texture properties) of the intratumoral 18F-fluorodeoxyglucose (FDG) uptake. The first and important step of this kind of analysis is to differentiate tumor region from other structures and background, which is called segmentation. In this study, k-means, active contour (snake), and Otsus tresholding methods were applied on PET images obtained from 36 patients and the performances were compared by the nuclear medicine expert in our team. The results show that Otsu tresholding approach is more selective.

Registration and fusion of lung tumor PET/CT images

Image fusion attracts attention in medical field due to complementary behavior and application such as diagnosis and treatment planning. In this study, first positron emission tomography (PET) and computed tomography (CT) images coming from 8 nonsmall cell lung cancer were registered then wavelet and principal component analysis methods were applied to fuse images. According to mutual information metric and nuclear medicine expert wavelet method gave better results when compared to PCA.

SHORT-TERM PROGNOSTIC VALUE OF REST Tc99m-MIBI GATED SPECT AFTER ACUTE NON-Q WAVE MYOCARDIAL INFARCTION

Aim: The purpose of this study is to determine the short–term prognostic value of technetium 99m methoxyisobutylisonitrile gated single photon emission computed tomography (Tc99m–MIBI Gated SPECT) in patients with acute Non–Q wave myocardial infarction (NQMI) in 30 days. Methods: We identified 36 patients who underwent rest Tc99m–MIBI Gated SPECT and who were followed-up 30.65±0.49 days after first a NQMI. 21 patients were males, 15 females, with a mean age of 60.30±10.17 years. Rest Tc99m–MIBI Gated SPECT were performed within 48 (30.7±2.3) hours of admission to the coronary care unit after acute myocardial infarction (MI). The left ventricular ejection fraction (LVEF), end diastolic (EDV) and end systolic volumes (ESV), and summed rest score (SRS) and extent score (ES) were assessed using rest Tc99m–MIBI Gated SPECT. Results: Rest Tc99m–MIBI Gated SPECT parameters and clinical datas were analyzed and divided two group according to prognosis, as new cardiac event (poor prognosis) and stable stuation (good prognosis). During follow-up, 12 patients (33%) had a new clinical event, [4 congestive heart failure (11%), 7 revascularization (19%) and 1 reinfarct (2%)], whereas 24 patients (66%) showed a good outcome. There were significant differences LVEF, EDV, ESV, SRS and ES values between poor and good prognosis group (p=0.011, p=0.016, p=0.017, p 70 ml (RR=5.31, CI 1.17 to 24.14, p=0.027), SRS≥7 (RR=7.00, CI 1.25 to 39.14, p=0.032) and ES≥3 (RR=6.59 CI 0.72 to 60.02, p=0.037). Conclusion: Left ventricular parameters (LVEF, ESV) and perfusion scores (SRS, ES) which obtained by rest Tc99m–MIBI Gated SPECT, provide useful information in the prediction of future cardiac events after NQMI in 30 days.