Erkan Ibis

Brain SPECT findings in long-term inhalant abuse.

This study evaluates brain perfusion in long-term inhalant abusers of toluene, acetone, benzene and derivatives. Ten patients in the age range 16-18 years (mean, 17.3±0.67 years), who had been inhalant dependent for a mean period of 48.3±6.2 months, but who had stopped using inhalants for 1-11 months (mean, 5.4±2.1 months), and ten controls (mean age, 17.3±0.67 years) were included in the study. Psychiatric tests, biochemical tests and Tc-99m-hexamethylpropyleneamine oxime (Tc-99m-HMPAO) brain single photon emission computed tomography (SPECT) were performed on all patients. Brain SPECT images were evaluated qualitatively and quantitatively. The mean IQ level was found to be 84 (by psychological tests). Brain SPECT showed non-homogeneous Tc-99m-HMPAO uptake and hypoperfusion areas in all patients (five left temporal, one right temporal, two left temporal plus bilateral parietooccipital, one biparietal and one left temporoparietal). Seven patients had hyperperfused foci (unifocal in five patients and multifocal in two patients). Six hyperperfused foci were in a parietal and one in a temporoparietal location. This study suggests that inhalant dependents exhibit serious abnormalities in brain SPECT images, including hypo-hyperperfusion foci and non-homogeneous uptake of the radiopharmaceutical. A further study with a larger number of patients and long-term follow-up may help to reach a more specific conclusion.

The role of 18f-fdg Pet/ct in detecting colorectal cancer recurrence in patients with elevated Cea levels

IntroductionIn 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 methodPatients 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’. ResultsIn 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. Conclusion18F-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.

The additive clinical value of 18F-FDG PET/CT in defining the recurrence of disease in patients with differentiated thyroid cancer who have isolated increased antithyroglobulin antibody levels.

Aim The aim of this study was to investigate the additive clinical value of 18F-FDG PET/CT in defining the recurrence of disease in patients with differentiated thyroid cancer (DTC) who have isolated increased antithyroglobulin antibody (TgAb) levels with undetectable thyroglobulin (Tg) levels and negative 131I whole-body scintigraphy (wbs). Materials and Methods Clinical follow-up data of 231 patients with DTC who underwent 18F-FDG PET/CT between June 2006 and March 2011 were evaluated retrospectively. There were a total of 48 patients who underwent 18F-FDG PET/CT for isolated increased serum TgAb levels. When 17 patients who have lymphocytic thyroiditis were excluded, the remaining 31 patients [27 women and 4 men; mean (SD) age, 50.29 (15.2) y] were included in this study. The inclusion criteria were undetectable serum Tg and increased TgAb levels under the condition of thyroid-stimulating hormone greater than 30 IU/mL with negative 131I wbs and absence of pathologic findings in neck ultrasound and thoracic CT if performed. Findings from the 18F-FDG PET/CT were compared with the clinical follow-up data and the results of histopathologic examinations. Results Results of 18F-FDG PET/CT were negative in 15 and positive in 16 patients. Sixteen FDG-positive sites (15 lymph nodes and 1 bone) were seen in 16 patients who had positive findings in 18F-FDG PET/CT. In the comparison with 18F-FDG PET/CT findings and clinical follow-up data and histopathologic examination results, 4, 12, 2, and 13 patients were false-positive, true-positive, false-negative and true-negative retrospectively. In the receiver operating characteristic analysis, a 5.4 cutoff SUVmax value was calculated with 82% sensitivity and 81% specificity in distinguishing malignant and benign lesions. As a result, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 18F-FDG PET/CT in the detection of recurrent disease were calculated as 75%, 76%, 75%, 86%, and 80%, respectively. Conclusions Isolated increased TgAb levels might be a predictor of the recurrent DTC and 18F-FDG PET/CT might be an additive imaging method in detecting the recurrent disease in patients with DTC who have increased TgAb levels with undetectable Tg levels and negative 131I wbs.

Palliative analgesic effect of Re-186 HEDP in various cancer patients with bone metastases

The clinical picture of bone metastases is manifested by pain and loss of mechanical stability. Standard treatment options for bone metastases include external beam radiotherapy and the use of analgesics. Due to a large number of lesions in many patients, the use of radionuclide therapy with beta emitters may be preferable. Re-186 hydroxyethylidene diphosphonate (Re-186 HEDP) is one of the radiopharmaceuticals suitable for palliative treatment of metastatic bone pain. The aim of this study was to investigate palliative and side effects of Re-186 HEDP in patients with different types of cancers.Material & Method: Thirty one (17 male, 14 female) patients with various cancers (10 prostate, 10 breast, 4 rectum, 5 lung, 2 nasopharynx) and bone metastases were included in the study. Therapy was started with a fixed dose of 1295 MBq of Re-186 HEDP. If necessary, the same dose was repeated at least 3 times after an interval of 10–12 weeks; A total of 40 standard doses were given; 6 patients received repeated doses (3 doses in 3 patients, 2 doses in 3 patients). The patients with bone marrow suppression were excluded from the study. The pain relief was assessed the Eastern Cooperative Oncologic Group (ECOG) and the Karnofsky status index. All patients were evaluated with standard evaluation forms filled in daily for a maximum of 10 weeks.Results: The mean response rate was 87.5% in patients with breast and prostate cancer, 75% in patients with rectum cancer and 20% in patients with lung cancer. The overall response rate was 67.5%. The palliation period varied between 6 and 10 weeks, with a mean of 8.1±1.3 weeks. The maximal palliation effect was observed between the 3rd and 7th weeks. No serious side effects were seen except mild hematologic toxicity.Discussion & Conclusion: It is concluded that Re-186 HEDP is a highly effective agent in the palliation of metastatic bone pain in patients with prostate, breast and rectum cancer, but not effective in lung cancer. On the other hand, Re-186 seems to be a good alternative to Sr-89 because of its preferable physical characteristics (such as short half life and gamma energy emission), low side effect profile, early response and repeatability.

Radioiodine whole-body scans, thyroglobulin levels, 99mTc-MIBI scans and computed tomography : results in patients with lung metastases from differentiated thyroid cancer

ObjectivesThe correlation between a 131I whole-body scan (WBS), a 99mTc sestamibi (99mTc-MIBI) WBS, a computed tomography (CT) scan and the value of routine follow-up for 131I WBS and thyroglobulin (Tg) levels in patients with lung metastases from differentiated thyroid cancer was assessed. MethodPulmonary metastases were detected in 32 patients out of 583 with differentiated thyroid cancer (DTC) who were admitted to our clinic between 1985 and 2004 (age range, 22–79 years; mean, 58±19 years; 15 women and 17 men). Pulmonary metastases were diagnosed by considering the 131I WBS, increased Tg levels and/or other positive radiological findings. Papillary carcinoma was diagnosed in 15/32 patients and follicular carcinoma in 13/32. A mixed type found in 4/32 patients was classified histopathologically. A total of 3.7–53.65 GBq (100–1450 mCi) 131I was given to each patient. The duration of follow-up ranged from 36 to 240 months. A 131I WBS, the determination of Tg levels and/or a CT scan were carried out in the assessment of a diagnosis and follow-up of patients with lung metastases. A 99mTc-MIBI WBS was performed on 19 patients who were chosen at random from the 583. ResultsNineteen of 32 patients had lung metastases before they received the first 131I treatment. Six of the 32 had distant-organ metastases other than in the lungs. Four of these six patients had only lung and bone metastases. Pulmonary metastases were observed on the 131I WBS patients 31/32 (96.8%) whereas no pulmonary metastases, were detected on the CT scans in 3/32 patients. The last diagnostic whole-body scan (DWBS) was normal in 13/32 patients. At the first examination, the Tg levels in 27/32 (84.4%) patients were below 30 ng · ml−1. At the final examination, 20/32 (62.5%) patients had Tg levels higher than 30 ng · ml−1, while Tg levels were lower than 30 ng · ml−1 in 12/32 patients. Tg levels decreased in 21/32 and increased in 3/32 patients. The 131I WBS continued to be abnormal in 2/3 patients with increased Tg levels but became normal in one patient whose CT scan still showed macro-nodular lesions. Tg levels did not change significantly in 8/32 patients. The 131I WBS became normal in 5/8 patients, while the CT scans for 4/5 showed micro-nodules. Metastases were detected in 12/19 patients who underwent 99mTc-MIBI whole-body scanning: 18/19 showed metastases on the 131I WBSs and 17/19 on the CT scans. Of the seven patients without a sign of metastasis on the 99mTc-MIBI WBS, one was negative in terms of metastasis on the 131I WBS and one on the CT scan. Fibrosis was observed on the CT scans of 2/32 patients. One patient developed dedifferentiation, as determined by the negative 131I WBS and positive CT scan. Conclusion131I whole-body scanning and the determination of Tg levels are the most important procedures for the evaluation of lung metastases in differentiated thyroid cancer. Computed tomography is a useful addition to 131I whole-body scanning. MIBI imaging alone may not be enough to detect lung metastases from differentiated thyroid cancer.

Regional cerebral blood flow in children with ADHD: changes with age

The aim of this study was to investigate the changes in regional cerebral blood flow (rCBF) with age in patients with attention deficit hyperactivity disorder (ADHD). Twenty-nine drug-naive ADHD subjects (24 boys, 5 girls; age 7-13; mean+/-SD=age 9.2+/-2.1) and 12 subjects with epilepsy (all diagnosed as having complex partial seizure, 6 boys, 6 girls; age 7-14; mean+/-SD=8.5+/-2.1) were included in the study. All cases of ADHD were diagnosed according to DSM-IV criteria. Cerebral blood flow was evaluated with Tc-99m-hexamethylpropyleneamine oxime (Tc99m HMPAO) brain single photon emission tomography (SPECT) during standard resting condition in all of the cases. Asymmetry indices for each region of interest were calculated. Absolute rCBF values were normalized as the absolute rCBF values divided by the whole brain absolute value. The prefrontal lobe asymmetry indices were significantly negatively correlated with age in ADHD cases (r=-0.408, P=0.025), which indicated the increased prefrontal rCBF lateralization from the right to the left side with age. When ADHD cases older than 7 years of age were compared with those with epilepsy, the ADHD cases had lower right prefrontal and frontal rCBF and higher left parietal rCBF. The epilepsy group showed no significant correlations between age and asymmetry indices and showed a different developmental trajectory for prefrontal asymmetry and right prefrontal rCBF values. The results indicated that the left hemisphere dominance in the prefrontal cortex significantly increases with age in ADHD cases.

Evaluation of cardiac functions in patients with thalassemia major

It is known that a blood transfusion is necessary for survival in patients with thalassemia, but it may cause myocardial dysfunction due to myocardial siderosis as in other organs. The aim of this study was to evaluate myocardial perfusion by means of stress thallium scanning (MPS) and left ventricular functions by rest radionuclide ventriculography (RNV).Twenty-one patients at ages 9–16 (mean 12.1 ± 3.2) who have been diagnosed with thalassemia for 4–15 years (mean 12.7 ± 4.8) were included in the study. They had blood transfusions 78–318 times (mean 162.1 ± 71). MPS and RNV was performed within two days after the any transfusion. MPS showed ischemia in 3 patients and normal perfusion in 18 patients. RNV revealed normal systolic parameters (wall motion, EF, PER, TPE) but diminished diastolic parameters (TPF, PFR) compared with normal values (p < 0.05).We conclude that ischemia or fixed defects may be seen in stress MPS as a result of cardiac involvement in patients with thalassemia. But, RNV is an important and preferable test for the early detection of subclinic cardiomyopathy. RNV may therefore show diastolic abnormalities before the systolic abnormalities show up.

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.

Prognostic importance of 18F-FDG uptake pattern of hepatocellular cancer patients who received SIRT.

Purpose The aim of the study was to evaluate the effect of 18F-FDG uptake pattern of liver lesions to treatment response of patients who received yttrium-90 (Y-90) selective internal radiation therapy (SIRT) for hepatocellular cancer (HCC). Patients and Methods Nineteen patients (5F, 14M, mean age: 64.5 ± 14.7 years old, range: 57–73 years) who received SIRT treatment in our department for HCC between June 2008 and May 2011 were included in the study. All patients underwent 18F-FDG PET/CT before SIRT for evaluation of disease stage and metabolic activity of liver lesions. Patients were divided into 3 groups according to FDG uptake patterns of primary liver lesions (hypoactive, nonhomogenous, and focal intense). Progression-free survival (PFS) times of each group and patients with hepatic only and hepatic with extrahepatic disease were analyzed. Disease progression criteria were increase in tumor volume, progressive elevation of serum alpha-fetoprotein levels, and detection of extrahepatic metastases. Kaplan-Meier analysis was used for comparison of PFS times. Results The mean treatment dose was calculated as 1.4 ± 1.0 GBq. While liver lesions of 4 patients were hypoactive in pretreatment 18F-FDG PET/CT, liver lesions of 6 and 9 patients had nonhomogenous and intense FDG uptake, respectively. Mean PFS time of patients who had hypoactive liver lesions was 5.25 ± 1.52 months. In patients who had liver lesions with nonhomogenous uptake, mean PFS time was 12.3 ± 2.6 months. Lastly, in patients with intense uptake in liver lesions, PFS time was calculated as 19.8 ± 5.0 months. Difference between each group was statistically significant (P = 0.017). There was no significant difference in the PFS of the patients with limited hepatic disease and patients with extrahepatic involvement. Conclusion In patients with unresectable HCC, higher SUVmax lesions unexpectedly had better PFS rates after SIRT, suggesting SIRT has a treatment advantage over other therapeutic options in these patients.

Impact of ¹⁸F-FDG PET/CT for detecting recurrence of medullary thyroid carcinoma.

ObjectiveThe aim of this study was to evaluate the value of fluorine-18 (18F) fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in the detection of recurrent medullary thyroid carcinoma (MTC) in patients with elevated calcitonin levels. MethodsThirty-three patients (nine men, 24 women; mean age: 50.3±12 years) who were referred to undergo 18F-FDG PET/CT for restaging of MTC in patients with high calcitonin levels were included in this study. Five patients also had suspected lymph nodes detected by neck ultrasonography. The results of 18F-FDG PET/CT and clinical follow-up data were reviewed retrospectively. Histological analysis has been accepted as the gold standard in the confirmation of 18F-FDG PET/CT results. Patients were followed up for 45.6±4.2 months. ResultsThere were 14 negative and 19 positive scans for possible recurrence of MTC. In the positive scans, the possible recurrence sites were neck lymph nodes, thyroid bed, mediastinal lymph nodes, and the lung in 14, two, two, and one patient, respectively. Disease recurrence in 13 patients was confirmed histologically by surgical excision or fine-needle aspiration biopsy. In the remaining six patients, recurrence was excluded as it was reactive as a result of pathological examination. However, one patient had a negative scan, underwent neck lymph node excision after 18F-FDG PET/CT examination, and lymph node recurrence was detected histologically. According to these results, the sensitivity and specificity of PET/CT were calculated as 93 and 68%, respectively. According to the recommended calcitonin level by the American Thyroid Association (calcitonin levels higher than 150 pg/ml), sensitivity was calculated as 90%. Although the mean maximum standardized uptake values of the true-positive and false-positive groups were calculated as 4.72±2.17 and 4.22±1.02, respectively, the difference between the two groups was not statistically significant (P>0.05). ConclusionPET/CT is a sensitive imaging tool in the detection of MTC recurrence, especially in patients with high calcitonin levels, and it gives additional information in one third of all patients on an average by detecting an occult disease or confirming findings of other imaging tools.