Eser Lay Ergün

Regional cerebral blood flow and neuropsychological functioning in early and late onset alcoholism.

The aim of the study was to compare late and early onset alcoholism with regard to regional cerebral blood flow (rCBF) and neuropsychological functioning. Ten late onset and 13 early onset male alcoholics were included in the study, the criterion being the age of onset for alcohol abuse. Six healthy male volunteers were included as a control group. Regional measures of cortical cerebral blood flow were assessed using Tc-99m-HMPAO single photon emission computed tomography (SPECT) after a detoxification period. When compared with the control group, the early onset group showed reduced relative perfusion in the left superior frontal region, while relative perfusion in the late onset group was deficient in both right and left superior frontal regions. Both groups of alcoholic patients also displayed impairment in frontal lobe functions and non-verbal memory. The results of this study indicate that early onset alcoholism is associated with hypoperfusion in the left superior frontal region while the late onset subtype is characterized by uniformly hypoperfused left and right superior frontal regions. Additionally, both groups of alcoholic patients exhibit an almost identical pattern of neuropsychological abnormalities mainly related to frontal lobe functions and non-verbal memory. Collectively these findings support previous evidence suggesting a key role of frontal lobe pathology in understanding the neurobiology of alcoholism.

The effect of clozapine on regional cerebral blood flow and brain metabolite ratios in schizophrenia: Relationship with treatment response

The purpose of this study was to investigate the effect of clozapine on regional cerebral blood flow (rCBF) and its relationship with response to treatment. In addition, we aimed to study the influence of clozapine on proton magnetic resonance spectroscopy ((1)H-MRS) findings in the dorsolateral prefrontal cortex (DLPFC) in a subgroup of patients. Psychopathology, neurocognitive functioning, and SPECT imaging of 22 patients were assessed at the baseline and 8 weeks after the initiation of clozapine treatment. In 10 of these patients intermediate-echo (TE: 135 ms) single-voxel (1)H-MRS was also performed at the baseline and after 8 weeks. Clozapine treatment increased the right frontal (superior and medial)/caudate perfusion ratio in the whole group, while it increased bilateral frontal (superior and medial)/caudate perfusion ratios in treatment responders. In addition, percentage changes in left and right frontal (superior and medial)/caudate perfusion ratios compared to the baseline were higher in treatment responders than in non-responders. The improvement in attention was related to the increase in percentage change in the right frontal (superior and medial)/caudate perfusion ratio, while the improvement in verbal fluency was related to the increase in percentage changes in both right and left frontal (superior and medial)/caudate perfusion ratios and to right frontal (superior and medial)/thalamus perfusion. Baseline frontal (superior and medial)/thalamus perfusion could explain 32% of the variability of percentage improvements in psychopathology. (1)H-MRS showed that the baseline PANSS general psychopathology score was inversely correlated with the baseline NAA/Cre ratio. An increased NAA/Cre ratio in DLPFC after 8 weeks of clozapine treatment was also revealed by (1)H-MRS. Our SPECT imaging results suggest the presence of an imbalance in fronto-striato-thalamic circuitry that changes with clozapine, especially in the responders, while (1)H-MRS results indicate a supportive effect of clozapine on neuronal integrity.

Unusual extracardiac findings detected on myocardial perfusion single photon emission computed tomography studies with Tc-99m sestamibi.

The authors describe the incidence and various uptake patterns of Tc-99m sestamibi (MIBI) in the extracardiac area due to unusual causes on myocardial perfusion single photon emission computed tomography (SPECT) studies. Seven patients are presented in whom incidental extracardiac findings were observed during the interpretation of the raw data besides the routine evaluation of myocardial reconstructed SPECT slices. These 7 patients were detected out of 582 consecutive patients (1.2%) who had myocardial perfusion SPECT with Tc-99m MIBI. The findings on the raw data led to additional reconstruction of thoracic SPECT images and eventually detailed examination of the extracardiac area. Two of the patients underwent surgery because of incidental extracardiac findings (thymoma and multinodular goiter) on cardiac scintigraphy. Other causes of increased extracardiac activity were the intestine protruded through the left hemithorax, uptake in the pulmonary arterial wall, and pulmonary interstitial fibrosis due to sarcoidosis. The reasons for decreased Tc-99m MIBI accumulation in the extracardiac area in the 2 other patients were significantly dilated pulmonary arteries and hydatic cyst, which were not defined before to our knowledge. Familiarity with the normal biodistribution and variable uptake patterns in the raw images becomes necessary during the interpretation of myocardial SPECT in order not to miss very unusual incidental extracardiac uptake or information that could lead to alteration in patient management. Potential underlying mechanisms of extracardiac Tc-99m MIBI accumulation are discussed, and the literature about noncardiac Tc-99m MIBI findings detected on myocardial perfusion SPECT studies was reviewed.

SPECT in periodic lateralized epileptiform discharges (PLEDs): a case report on PLEDs.

Periodic lateralized epileptiform discharges (PLEDs), which are known as unusual electroencephalogram (EEG) patterns, are described in a patient who had stroke and seizures. This patient underwent Tc-99m HMPAO (hexamethyl propylene amine oxime) brain single photon emission computed tomography (SPECT) imaging both during PLEDs on EEG and after the cessation of PLEDs. The initial SPECT study revealed increased CBF in the left frontal and parietal cortex extending through the left temporal region and in the left basal ganglium. After the PLEDs disappeared, the second SPECT study showed decreased perfusion on the left frontal and parietal region in the brain. Brain SPECT findings supported the contention that PLEDs may be an ictal phenomenon. Here we also present a review on PLEDs and contributions of brain SPECT as a functional imaging modality to investigate the underlying mechanism of this interesting EEG pattern.

Positron emission tomographic-computed tomographic imaging of a uterine sarcoma

Metabolic imaging by positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG) is performed in patients to stage, restage, and follow neoplastic disease and to evaluate possible malignant tumors. Combined PET and computed tomography (CT) is a more recent and developing imaging method and has the advantage of supporting both morphologic and functional information simultaneously. A 62-year-old woman with abdominal fullness, a feeling of heaviness, and vaginal bleeding was examined with abdominal-pelvic ultrasonography that indicated a mass in the uterus. The patient was referred for PET-CT for evaluation of this uterine mass. FDG-PET imaging revealed substantial FDG uptake in the uterine mass. The CT scans showed the mass clearly. The combined PET-CT imaging was impressive and highly indicative of uterine cancer. The patient underwent hysterectomy. Biopsy revealed leiomyosarcoma. The case reported here indicates the effectiveness of combined PET-CT for the diagnosis of uterine sarcoma and the differentiation of malignant and benign lesions by using both morphologic and functional information.

99Tcm-MAA lung scintigraphy in patients with Behçet's disease : Its value and correlation with clinical course and other diagnostic modalities

Behçets disease, initially described as local vasculitis involving the oral, genital mucosa and eyes, can affect many organ systems with a varying clinical course. Pulmonary lesions associated with Behçets disease are rare and reported to have a prevalence of 1.0-7.7%. In this prospective study, 29 patients aged 16-60 years (mean±s: 34±10.5) were investigated for pulmonary involvement with direct radiography, computerized tomography (CT) and intravenous digital subtraction angiography. Lung scintigraphy was also performed to determine its diagnostic value. In addition, patients had a fibreoptic bronchoscopic examination, spirometric test, carbon monoxide diffusion test and methacholine test. Of the 29 patients with Behçets disease, 17 had pulmonary involvement. The diagnostic criteria for pulmonary vasculitis and tracheobronchial tree involvement were: (1) hilar vascular prominence or mass, new alveolar and reticulonodular infiltrates on chest X-ray; (2) aphthous lesions, bleeding ulcerations, inflamed mucosal appearance on bronchoscopy; (3) vascular thrombosis or aneurysms on CT; (4) occlusion or aneurysms of the main pulmonary arteries or its branches. The value of lung scintigraphy and its correlation with other imaging modalities were investigated to determine if a lung perfusion scan alone can be used to detect pulmonary involvement in Behçets disease. Twenty-six patients were investigated with lung scintigraphy. Thirteen of 14 patients with lung involvement were identified. Perfusion lung scintigraphy provided true diagnostic information in 96% of our patients. In eight patients without pulmonary involvement, the lung scans were normal. Although DSA specifically demonstrates pulmonary aneurysms, it involves administration of contrast media and cannot show abnormalities distal to the third pulmonary arterial branches. Although vasculitis caused by collagen disorders is physiologically indistinguishable from pulmonary emboli, most perfusion defects resolve within 3 months, which can be used as a differential diagnostic criterion in the appropriate clinical setting. Therefore, pulmonary perfusion imaging can be used to screen patients suspected of having lung involvement, especially in the absence of thrombophlebitis. In patients with thrombophlebitis, a repeat examination at 3 months is recommended to differentiate pulmonary involvement from pulmonary embolism.

Diaphragmatic and Crural FDG Uptake in Hyperventilating Patients: A Rare Pattern Important to Recognize

The authors describe various patterns of F-18 fluorodeoxyglucose (FDG) accumulation in the diaphragm and crura. They present 6 patients in whom incidental diaphragmatic and crural uptake of FDG was observed during positron emission tomography (PET). Hyperventilation is thought to be the potential underlying mechanism of this condition.

Tc-99m DTPA acetylsalicylic acid (aspirin) renography in the detection of renovascular hypertension.

Purpose Prostaglandins play important roles in renal physiology and in the development of renovascular hypertension. In a recent study, inhibition of renal prostaglandin synthesis was found to be useful for detecting renovascular hypertension using renal scintigraphy. In the current study, the authors evaluated the role of aspirin (an inhibitor of prostaglandin synthesis) and compared it with Tc-99m DTPA captopril renal scintigraphy (CS). Materials and Methods Twenty-five patients were examined with Tc-99m DTPA in a three-step manner: a baseline study, CS, and aspirin scintigraphy (AS). Each scintigraphic study was interpreted visually and according to the renogram curve patterns. Semiquantitative parameters (Tmax, renal indices [%], 20-minute/max count ratio, glomerular filtration rate) were also calculated. Plasma renin activity was determined for each study. The blood pressures of all patients were measured during AS. All patients had a contrast-enhanced angiogram that was used as the reference test. Results Three groups of patients were observed based on the scintigraphic and angiographic results. In each group, no difference was observed in blood pressure after aspirin administration. In group 1, seven patients had normal angiographic and scintigraphic results. In group 2, eight patients had angiographically confirmed renal artery stenosis (RAS). In 6 patients (mean, 47% RAS), both AS and CS were negative for RVH. In the remaining two patients with RAS (mean, 83% stenosis), the kidneys were atrophic on the stenotic side, and thus the kidneys did not respond to the interventions. No difference was observed in plasma renin activity in groups 1 and 2. Group 3 included 10 patients who had angiographically confirmed RAS (mean, 86%). In 9 patients, both CS and AS were positive for RVH. In the remaining one patient, scintigraphic results were falsely negative. Statistical analyses performed for semiquantitative parameters did not reveal any significant difference in this group, although there was a tendency toward prolonged Tmax values after captopril and aspirin administration. In four cases, unexpected elevation of plasma renin activity was observed in group 3. Conclusions These data indicate that AS with Tc-99m DTPA is an alternative for CS. It has the advantage of having no effect on blood pressure and does not require that angiotensin-converting enzyme inhibitors be discontinued. Although in this study 9 of 10 patients had correct diagnoses of RAS, further studies, especially using tubular agents with the calculation of parenchymal transit time, might provide valuable information in this patient group. An ongoing study is being performed in the authors’ institute.

Comparison of Tc-99m EC and Tc-99m DTPA captopril scintigraphy to diagnose renal artery stenosis.

PURPOSE Although, captopril scintigraphy is a well established method to detect renovascular hypertension, the optimal radiopharmaceutical for this test remains to be determined. Recently, Tc-99m ethylenedicysteine (Tc-99m EC) appeared as an alternative agent for captopril scintigraphy. The aim of this study was to compare the diagnostic accuracy of Tc-99m EC with Tc-99m DTPA, which is a well-established renal radiopharmaceutical for the captopril test. METHODS Nineteen hypertensive patients who had various degrees of renal artery stenosis on angiography were included in the study. All patients had baseline and captopril Tc-99m EC and Tc-99m DTPA scintigraphy within a 1-week period. The results were compared with angiography and in eight patients with changes in blood pressure after revascularization. The images were interpreted without knowledge of the angiography and revascularization data as low, intermediate, or high probability for hemodynamically significant renal artery stenosis, which was defined as an area of stenosis exceeding 50%. RESULTS Tc-99m EC and Tc-99m DTPA study results were in agreement in 16 of the 19 patients. In two patients with branch artery stenosis, Tc-99m EC was definitely superior to Tc-99m DTPA and correctly identified the probability of stenosis on scintigraphy. On kidney analysis, Tc-99m EC had a slightly greater diagnostic sensitivity compared with Tc-99m DTPA (79% vs. 68%; P > 0.05 by the chi-squared test) but equal specificity (93% for both agents). Both Tc-99m EC and Tc-99m DTPA showed the same accuracy in predicting the outcome after revascularization in all but one patient with branch artery stenosis, in whom Tc-99m EC accurately predicted a successful outcome of the intervention but Tc-99m DTPA did not. Tc-99m EC had better renal uptake in patients with decreased renal function and provided more dramatic evidence of renogram changes after captopril intervention, which resulted in more confident interpretation. CONCLUSIONS There is no significant difference between Tc-99m EC and Tc-99m DTPA captopril scintigraphy for detecting renal artery stenosis. However, because of the better imaging characteristics and more confident interpretation provided by the dramatic changes in the degree of renogram abnormality after captopril intervention, Tc-99m EC captopril scintigraphy should be used, particularly in patients with decreased renal function or branch artery stenosis.

Metastatic insular thyroid carcinoma: visualized on Tc-99m pertechnetate, Tc-99m MDP and iodine-131 scintigraphy; a review of the literature for other radionuclide agents.

Poorly differentiated insular thyroid carcinoma is classified as a separate entity among other tumors of the thyroid gland. Its histological pattern and clinical course are regarded as intermediate between well-differentiated and anaplastic thyroid cancer. The authors report Tc-99m pertechnetate, Tc-99m MDP and radioiodine imaging features in a 33-year-old male patient with metastatic insular carcinoma of the thyroid. The extent of involvement was almost identical in all three studies. Insular carcinoma of the thyroid was shown by biopsy, and the patient received a cumulative dose of 14,800 MBq (400 mCi) radioactive 1–131. Other radionuclide imaging agents are also reviewed.