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C Bekdik

Publications and source records attributed to C Bekdik.

At least 19 recordsLinked to original sources
PubMed2000

Impact of radiotherapy on normal brain tissue: semi-automated quantification of decrease in perfusion.

PURPOSE: We attempted to ascertain the impact of Co-60 conventional external radiotherapy (cRT) on the perfusion of normal brain tissue in relation to the radiation doses delivered to the tumors in patients with primary brain tumors. MATERIALS AND METHODS: After surgery 18 patients (pts) were due to undergo cRT with a total dose of 5400- 6400 cGy. All the patients had a Tc-99m-HMPAO SPECT study prior to cRT (basal), 15th and 30th days of cRT as well as 1 (in 6 pts), 3 (in 9 pts), and 6 (in 3 pts) months after cRT. For quantitative evaluation, the entire set of transverse slices were divided into 4 regions as frontal, parietal, occipital and temporal regions by means of a computer software program. Semi-automated quantification was performed on a total of 1392 regions in 87 studies to determine left to right ratios. An interregional difference of at least 10% was considered abnormal. RESULTS: After elimination of tumor sites, 80 normal brain regions showed decreased perfusion after cRT. The percent decrease in perfusion was (mean 22.5+/-9.9) significantly higher in areas irradiated with doses > 3000 cGy (p < 0.05). CONCLUSION: cRT has adverse effects on the perfusion of normal brain tissue for doses > 500 cGy. Our findings justify treating patients with small and limited lesions with stereotactic radiotherapy in order to minimize the adverse effects of cRT on normal tissues.

Adolescent↗
PubMed1997

Effect of an additional atropine injection during dobutamine infusion for myocardial SPET.

The aim of this study was to examine the value of an additional atropine injection in patients who do not achieve an adequate heart rate during dobutamine infusion for myocardial perfusion SPET (single photon emission tomography). Patients undergoing dobutamine myocardial SPET who failed to achieve > or = 85% of their age-predicted maximal heart rate at the end of dobutamine infusion (D protocol) had a second dobutamine myocardial SPET study on a separate day with the addition of an atropine injection during the dobutamine infusion (D + A protocol). Twenty-nine patients were studied. 201Tl was used in 27 patients and 99Tc(m)-MIBI in two patients. All patients underwent coronary angiography and significant coronary artery disease was found in 19 of 29 patients. The mean heart rate obtained at the peak of dobutamine infusion in the D + A protocol was significantly higher than that in the D protocol (153.8 +/- 13.8 vs 117.5 +/- 15.3 beats min[-1]). The D + A protocol resulted in a higher diagnostic sensitivity for the detection of stenosed coronaries compared with the D protocol (87 vs 80%, P > 0.05) without changing the specificity (89% for both protocols). On the other hand, the frequency of side-effects and ECG changes during the D + A protocol was higher than that with the D protocol (32 vs 47). In conclusion, the addition of an atropine injection during dobutamine infusion resulted in a higher diagnostic sensitivity for identifying stenosed coronaries compared to dobutamine alone.

Adrenergic beta-Agonists↗
PubMed1997

Dobutamine thallium-201 myocardial SPECT in patients with left bundle branch block and normal coronary arteries.

UNLABELLED: Dobutamine is a positive inotropic and chronotropic agent and is being widely used as a pharmacologic stress agent in patients unable to achieve maximal dynamic exercise test. The purpose of the current study was to document the dobutamine induced false-positive septal defect in terms of its frequency and extent on 201Tl myocardial SPECT in patient with left bundle branch block (LBBB). METHODS: Twenty-five symptomatic patients with LBBB underwent dobutamine and redistribution 201Tl myocardial SPECT studies. Coronary angiographies were also performed. Only those patients with normal coronaries (n = 19) were included in the study. For each study, tomograms were divided into 19 segments, and each segment was analyzed qualitatively as to presence and type of perfusion defect (reversible or fixed). In addition, septal perfusion was scored in each patient (1 = markedly, 2 = moderately reduced, 3 = normal uptake). RESULTS: Sixteen of 19 patients (84.21%) had false-positive septal reversible perfusion defect, and the remaining 3 had normal images. Perfusion defects were confined to only the septum in 5 of 16 patients (31.25%), whereas a greater proportion of patients had septal defect extending to the contiguous myocardial areas, mainly to the anterior wall. Five of 16 patients with false-positive defects had a septal perfusion score of 1, while the remaining 11 had a score of 2. CONCLUSION: Dobutamine myocardial scintigraphy in patients with LBBB was misleading for the diagnosis of coronary artery disease, since up to 84.21% of patients had false-positive septal perfusion defects.

Adult↗
PubMed1996

Comparison of 99mTc(V)-DMSA, 201Tl and 99mTc-MIBI imaging in the follow-up of patients with medullary carcinoma of the thyroid.

Radionuclide scanning with tumour-seeking agents such as pentavalent technetium-99m dimercaptosuccinic acid [99mTc(V)-DMSA], thallium-201 and technetium-99m sestamibi (MIBI) has been reported to be useful in the detection of medullary thyroid carcinoma (MTC). We undertook a study in 14 MTC patients to determine the comparative imaging potential of 201Tl, MIBI and 99mTc(V)-DMSA in the detection of recurrent or metastatic MTC. All patients underwent total thyroidectomy and had persistently elevated serum calcitonin levels after the surgery. Scintigraphic studies were carried out 20 min after the injection of 111 MBq of 201Tl or 555 MBq of MIBI and 2 h following the injection of 370 MBq of 99mTc(V)-DMSA. All scintigraphic findings were correlated with contemporaneous CT or MRI studies. CT, MRI and bone scans showed 42 (26 bone, 16 soft tissue) metastatic sites in 11 of the 14 patients. In the remaining three patients no lesions were detected during diagnostic evaluation. 99mTc(V)-DMSA showed all of the soft tissue metastases but could not show two bone lesions. On the other hand, MIBI imaging was false-negative in 22 (52%) sites and 201Tl was false-negative in 34 (80%) sites. Overall, lesion detection sensitivities for 99mTc(V)-DMSA, MIBI and 201Tl were 95%, 47% and 19% respectively. We conclude that 99mTc(V)-DMSA is clearly superior to MIBI and 201Tl in the follow-up of MTC patients.

Adult↗
PubMed1996

Renovascular hypertension due to Takayasu's arteritis demonstrated by Tc-99m ethylenedicysteine captopril scintigraphy.

A 34-year-old woman with severe hypertension underwent Tc-99m ethylenedicycteine (Tc-99m EC) captopril renal scintigraphy. There was bilateral parenchymal retention of the tracer suggesting renal artery stenosis. Angiography confirmed bilateral renal artery stenosis and also demonstrated contour irregularities of the abdominal aorta, and stenosis in mesenteric and subclavian arteries with increased collateral circulation consistent with Takayasu's arteritis. In light of this case of renal artery stenosis, it was concluded that Tc-99m EC can be used successfully as a potential renal agent in the diagnosis of renal involvement in patients with Takayasu's arteritis.

Adult↗
PubMed1996

Technetium-99m-ethylenedicysteine in the diagnosis and follow-up of renovascular hypertension.

Technetium-99m-ethylenedicysteine (99mTc-EC) captopril scintigraphy performed in a patient with severe hypertension revealed increased parenchymal retention in the left kidney, suggesting renal artery stenosis. After angiographic confirmation of renal artery stenosis, percutaneous transluminal angioplasty (PTA) was performed on the left renal artery. Captopril scintigraphy after PTA showed normal findings with no evidence of parenchymal retention, consistent with reversal to normal kidney functions. In light of this case of renal artery stenosis, it was concluded that 99mTc-EC can be used successfully as a potential renal agent in the diagnosis and follow-up of renovascular hypertension.

Adult↗
PubMed1996

The diagnosis of renovascular hypertension with technetium-99m-ethylenedicysteine captopril scintigraphy.

RATIONALE AND OBJECTIVES: The authors present preliminary findings on the diagnosis of renovascular hypertension with technetium-99m-ethylenedicysteine (99mTc-EC). METHODS: Thirty-nine patients referred to the nuclear medicine department with clinical evidence of renovascular hypertension were included in the study. Baseline and captopril scintigraphies were done on separate days after the injection of 185 MBq of 99mTc-EC. All patients had angiographic correlation and 9 patients were shown to have renal artery stenosis. RESULTS: Quantitative analysis of the data showed no significant changes of perfusion index (PI), split renal function (SRF), and effective renal plasma flow (ERPF) values between pre- and postcaptopril studies in patients with significant renal artery stenosis (P > 0.05). Baseline and postcaptopril values for PI, SRF, and ERPF were measured as 128 +/- 21 and 116 +/- 12 mL/minute, 47 +/- 1 and 50 +/- 2 mL/minute, and 250 +/- 18 and 231 +/- 20 mL/minute, respectively. However, time to maximum activity (Tmax), time to half maximum activity (T 1/2), time to two thirds of maximum activity (T 2/3), and residual cortical activity (RCA) values showed marked changes with a rising renogram curve (P < 0.05). Baseline and postcaptopril values for Tmax, T 1/2, T 2/3, and RCA were measured as 3.1 +/- 0.1 and 20.2 +/- 1 minute, 5.4 +/- 0.4 and 45.4 +/- 3.1 minutes, 3.1 +/- 0.2 and 33.7 +/- 4.1 minutes, and 27 +/- 4 and 215 +/- 34 minutes, respectively. All scintigraphic studies showed good correlation with angiography and no false-positive or false-negative results were observed. CONCLUSIONS: This preliminary study demonstrates that 99mTc-EC has good potential for the diagnosis of renovascular hypertension and that a single diagnostic criteria, specifically a rising renogram curve, seems adequate. However, the authors' initial results should be confirmed in a broader patient population.

Adolescent↗
PubMed1996

Silent myocardial ischemia in Behçet's disease.

OBJECTIVE: Behçet's disease (BD) is a multisystemic disorder usually described as a triple symptom complex consisting of aphthous stomatitis, genital ulcerations, and uveitis. Vasculitis is a key feature of the disease, which may lead to functional disturbances in highly vascularized organs. However, cardiac involvement is seldom recognized. We investigated the prevalence of silent myocardial ischemia (SMI) in BD as the clinical presentation of microvascular disease. METHODS: Ambulatory cardiac monitoring (Holter) was used in 36 patients with BD to detect silent myocardial ischemia. 201Thallium myocardial perfusion scintigraphy and radionuclide ventriculography were also performed. All patients fulfilled International Study Group for Behçet's Disease criteria and 11 of them had major vascular involvement. The same method was also performed on 38 control subjects for comparison of SMI positivity in patients with BD. RESULTS: Ambulatory cardiac monitoring was performed for 9.2 +/- 0.9 h, mean heart rate was 82 +/- 9 bpm, and no serious rhythm disturbance was recorded. SMI was described in 9 of 36 patients (25%) (median age 38 years, range 30-46) as ST segment depression of 3.00 +/- 0.42 mm with a duration of 4.01 +/- 0.9 min. One SMI positivity only was recorded in the control group in a 52-year-old man with a stenotic lesion in the left anterior descending coronary artery (p < 0.001). Eight of 9 patients with SMI showed a partially reversible myocardial perfusion defect after exertion, and 7 demonstrated some degree of left ventricular wall motion abnormality by radionuclide ventriculography. Coronary angiography was normal in 7 of 9 patients with SMI. Additionally, 7 of 9 patients with SMI had major vascular involvement, while only 4 of 27 without SMI had major vascular disease (p = 0.0022). CONCLUSION: SMI incidence is significantly higher in BD compared to the control group. Impaired endothelial cell function may be the underlying cause in the pathogenesis of BD or of its vascular complications such as SMI.

Adult↗
PubMed1996

Segmental ATN in a kidney with a single artery transplanted from living related donor.

A sequential 99mTc-MAG3 renogram of a 20-year-old male who received a kidney from a living related donor is presented. Pre-transplant angiography of the donor showed the kidney had a single renal artery with upper and lower branches. The transplantation procedure was uneventful, allowing rapid simultaneous perfusion to the entire kidney. The first scan performed 2 days after the transplantation was normal except for retention of the radiotracer at the upper pole of the kidney. The renal collecting system was normal and no signs of dilatation or obstruction were noticed on ultrasonographic examination. A follow-up scan done on the 5th day of transplantation showed almost complete evacuation of the parenchymal retention previously seen on the upper pole of the kidney. This unusual finding was consistent with segmental acute tubular necrosis (ATN) of the upper pole of the kidney and showed that ATN might involve only a portion of a kidney in spite of the existence of a single artery of the transplant.

Adult↗
PubMed1994

Impaired lung epithelial permeability in diabetics detected by technetium-99m-DTPA aerosol scintigraphy.

UNLABELLED: The clearance of inhaled 99mTc-diethyl triaminepentaacetic acid (DTPA) aerosol from the lungs is used as an index of lung epithelial permeability. We investigated the involvement of the lung in diabetic patients using 99mTc-DTPA aerosol scintigraphy. METHODS: A total of 33 diabetic patients were studied. Thirteen had complications such as retinopathy and/or nephropathy (Group A) and 20 were without complications (Group B). As a control group, 20 healthy nonsmokers were studied. Dynamic scintigrams (2 min/frame, up to 30 min) were obtained following inhalation of 99mTc-DTPA through a radioaerosol delivery system. Time-activity curves were obtained and half-time (T1/2) of DTPA was measured from the curves. RESULTS: The mean T1/2 values (min +/- s.d.) were calculated to be 133.05 +/- 46.97, 93.67 +/- 21.23, 91.97 +/- 18.21 (Group A, Group B and controls, respectively). The mean T1/2 of Group A was significantly longer than controls (p < 0.005) and than that of Group B (p < 0.005) indicating decreased epithelial permeability. No such statistical difference was detected between Group B and controls (p > 0.05). CONCLUSION: The lung is a target organ in diabetes and lung involvement is closely related to other vascular complications. The presence of lung involvement can be readily detected by 99mTc-DTPA aerosol scintigraphy.

Adult↗
PubMed1993

Bleomycin lung toxicity detected by technetium-99m diethylene triamine penta-acetic acid aerosol scintigraphy.

In this study we investigated bleomycin-induced pulmonary toxicity in patients with germ-cell tumour by means of technetium-99m diethylene triamine penta-acetic acid aerosol scintigraphy. Twenty untreated patients who had no clinical or radiological evidence of pulmonary disease received four courses of etoposide, cisplatin and bleomycin chemotherapy. Aerosol lung scintigraphy and pulmonary function tests were performed in all patients before bleomycin treatment and after administration of 180 and 360 mg bleomycin. On the basis of the scintigrams the percentage decline in activity per minute (Kep) was evaluated, which represented an accurate parameter of lung membrane permeability. Pretreatment Kep values (0.891 +/- 0.286) were significantly lower than those obtained following 180 and 360 mg bleomycin treatment (1.176 +/- 0.336 and 1.389 +/- 0.477, respectively; P < 0.0005). The Kep values obtained with 180 and 360 mg bleomycin treatments were also significantly different (P < 0.005). In contrast, no significant change was observed in the results of pulmonary function tests. Our results demonstrate that evaluation of the pulmonary clearance of 99mTc-DTPA represents a useful means of monitoring the functional status of the lung epithelial membrane during bleomycin treatment. Further prospective studies are needed to assess the relationship between increase in permeability and development of lung toxicity in order to decide which patients should discontinue bleomycin therapy.

Adult↗
PubMed1993

Cerebral fat embolism studied with MRI and SPECT.

In a patient with fat embolism to the brain CT showed no abnormality. MRI performed after recovery from coma, when the patient had aphasia and quadriparesis, demonstrated multiple high signal abnormalities in the white matter on both T1- and T2-weighted images. HMPAO-SPECT showed left-sided hypoperfusion which resolved in parallel with clinical improvement 1 month later.

Adult↗
PubMed1993

Short-term effects of somatostatin analogue (SMS 201-995) on left ventricular function in healthy persons: a scintigraphic study.

Since somatostatin has been reported to have a negative inotropic and chronotropic effect on atria and positive inotropic effect on ventricle, present study was designed to investigate the acute effects of somatostatin analogue SMS 201-995 infusion on the left ventricular function in healthy volunteers. After labeling the autologous red blood cells with 750-1000 MBq 99mTc-pertechnetate, ECG-gated radionuclide ventriculography was performed. Using Fourier analysis of the left ventricular time-activity curve, ejection fraction (EF), peak ejection rate (PER), peak filling rate (PFR), time to end-systole (TES) and normalized TES/T values were calculated. Study group consisted of 12 healthy volunteers. Somatostatin analogue SMS 201-995 infusion was given at a rate of 100 micrograms/h during 2h. Baseline, 1st, 2nd h and 4th h imagings were done using the same protocol. Simultaneously heart rate and blood pressure were recorded. The difference between parameters was tested using Kruskall-Wallis test. The mean heart rate, systolic and diastolic blood pressures and did not show any statistically significant change during the somatostatin analogue infusion and 2h later in comparison to baseline values. The mean PER and PFR had a slight decrease at the first hour of infusion, but the change was not significant. However, the significant correlation of PER values with heart rate, EF and TES observed at baseline study were disappeared during the infusion. These results indicate that somatostatin analogue infusion does not appear to change the left ventricular systolic and diastolic function in healthy persons significantly.

Adult↗
PubMed1993

Preoperative localization of parathyroid carcinoma using Tc-99m MIBI.

A patient with parathyroid cancer is presented who underwent Tc-99m MIBI scintigraphy. The Tc-99m MIBI image demonstrated increased accumulation of activity at the lower pole of the left thyroid lobe which was later confirmed as a parathyroid cancer. Uptake by parathyroid cancer must be kept in mind as a cause of increased Tc-99m MIBI accumulation when a disease is in question in the thyroid or parathyroid gland.

Carcinoma↗
PubMed1993

Scintigraphic evaluation of the short- and long-term renal effects of oral felodipine using technetium-99m-mercaptoacetyl triglycine.

The short- and long-term effect of felodipine on renal perfusion and tubular function was investigated using a new renal tubular imaging agent, 99mTc-mercaptoacetyl triglycine (99mTc-MAG3). Twelve patients with essential hypertension (mean age = 49 +/- 8 years) were studied. Renal scintigraphies with 180 MBq 99mTc-MAG3 were performed at baseline, at the 2nd hour following oral administration of 5 mg felodipine and 4 weeks later on 5-10 mg daily felodipine therapy. The time-activity curves of each kidney were obtained following background subtraction. The 99mTc-MAG3 clearance value was measured for each kidney. In addition, perfusion index (PI), reno index, time to maximum, half-maximum and two thirds of maximum activity values of each kidney were calculated. Systolic and diastolic blood pressures were significantly lowered with long-term administration of felodipine (from 159 +/- 12/105 +/- 5 to 141 +/- 11/87 +/- 7 mm Hg, p = 0.01 and p = 0.002, respectively). Heart rate did not change significantly. Initially, a decrease in PI indicating an increase in renal blood flow (from 246 +/- 96 to 194 +/- 54, p = 0.01) was observed, whereas no change was noted during the chronic administration (to 230 +/- 69, p = NS). Total clearance of 99mTc-MAG3 was decreased nonsignificantly following the initial dose of felodipine (from 361 +/- 93 to 351 +/- 91 ml/min, p = NS). During long-term therapy, felodipine did not alter the perfusion and tubular function of the kidneys. Our results indicated that felodipine causes a significant increase in renal blood flow initially, even with a nonsignificant change in systemic blood pressure.

Administration, Oral↗
PubMed1993

Changes in the circulating endothelin and atrial natriuretic peptide levels during coronary artery bypass surgery.

To evaluate the behavior of circulating endothelin and atrial natriuretic peptide (ANP) during coronary artery bypass graft (CABG) surgery, blood samples from patients with coronary artery disease (n = 8) were investigated before, during and after operation. Plasma levels of endothelin and ANP were determined using the radioimmunoassay method. Baseline plasma levels were compared to those of normal volunteers (n = 6). Left ventricular function at rest and as a response to isometric exercise was evaluated using radionuclide ventriculography before and after coronary bypass surgery. The mean endothelin value was found to be within normal limits, however the mean ANP value was slightly higher than control. Patients had significantly improved left ventricular systolic and diastolic function after surgery. The mean endothelin level was higher than initial values immediately after extra-corporeal circulation and returned to initial values in two hours. However, ANP values were increased and remained higher than initial values. Baseline endothelin values were negatively correlated with systolic function parameters, whereas endothelin and heart rate had a positive correlation before extra-corporeal circulation. Coronary artery bypass graft surgery may cause an increase in the circulating endothelin level either due to endothelial injury or due to myocardial ischemia and hypothermia. Following surgery, increased endothelin levels returned to normal values immediately.

Aldosterone↗
PubMed1992

Ipsilateral and contralateral testicular blood flows during unilateral testicular torsion by 133Xe clearance technique.

Testicular blood flows during unilateral testicular torsion were measured by Xenon-133 clearance technique. Xenon-133 was injected via the left carotid artery into the heart. Measurements were performed in control and left-sided testicular torsion groups, each consisting of ten rats. Left and right testicular blood flows, which were 29.157 +/- 2.272 ml/100 g/min and 29.773 +/- 2.934 ml/100 g/min in the controls, were 11.983 +/- 3.655 ml/100 g/min and 16.098 +/- 3.757 ml/100 g/min in the experimental group and differed significantly. The decrease in contralateral testicular blood flow may play an important role in the contralateral testicular damage encountered following unilateral testicular torsion.

Animals↗