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Fevziye Canbaz

Publications and source records attributed to Fevziye Canbaz.

7 recordsLinked to original sources
PubMed2005

Myocardial perfusion defects with near-to-absent count reduction: a comparison of gated SPECT to radionuclide ventriculography in the determination of left ventricular function.

OBJECTIVE: The main aim of the study was, to estimate the impact of perfusion defects including significantly depleted areas of varying size on gated perfusion SPECT (GPS) determined ejection fraction (EF) measurements in comparison to radionuclide ventriculography (RVG). A secondary objective was the evaluation of the GPS-RVG agreement of EF in patients with normal and deteriorated left ventricular function, separately. METHODS: Fifty-nine patients having perfusion defects including at least one segment with no visible tracer uptake in rest myocardial GPS related to myocardial infarction (older than 15 days) were studied. Myocardial perfusion was visually analyzed using a 17 segment-model, on a five-point (0-4) grading system in which Grade-4 (0-9% maximal uptake) represents cold defects. The patients with >or=4 adjacent, with 2-3 adjacent and with 1 single cold segments were named as Group1(GR1), Group2(GR2) and Group3(GR3), respectively. Secondly, the patients were re-grouped according to RVG-EF values. (Group A: patients with EF<50%; Group B: patients with EF>or=50%). In each group, the GPS-EFs were compared with RVG performed within one week and also the variations of GPS-RVG EF differences among the groups were statistically analyzed. RESULTS: In overall (r=0.86) and in each subgroup, EFs obtained by GPS were well correlated with RVG. However, in overall (difference mean EF% [dEF%]=4.6+/-6.7, p<0.001) as well as in subgroup evaluation, GPS significantly (p<0.005) underestimated EF. There was no statistically significant difference in GPS-RVG EF variations between GR1, GR2 and GR3 (p>0.05). The RVG-mean differences and RVG-correlation coefficients calculated for GR1,GR2 and GR3 were dEF%=3.1+/-4.6, r=0.85; dEF%=3.7+/-6.03, r=0.80 and dEF%=6.2+/-8.03, r=0.79, respectively. Mean dEF% was statistically higher in group-B than group-A (mean difference of dEF%=4,2, p<0.05). In group-A, GPS-EF values were better agreed with RVG (dEF%=3.34, r=0.75) than in group-B (dEF%=7.52, r=0.53). CONCLUSION: The stability of the calculation algorithm of QGS in EF calculation of patients with large depleted infarct areas could be confirmed. The agreement of GPS determined EF is higher in patients having myocardial integrity loss and left ventricular dysfunction.

Algorithms↗
PubMed2004

Intracoronary versus intravenous injection of 99mTc-tetrofosmin: comparison of myocardial perfusion patterns and wall motion.

OBJECTIVES: The accuracy of viability and defect size detection by Tc-tetrofosmin has been discussed by several authors. The lower myocardial extraction fraction of the latter compared with Tc-sestamibi or Tl has often been emphasized. We hypothesized that the intracoronary (i.c.) injection of tracer activity, i.e. higher than that theoretically achievable in the case of intravenous (i.v.) administration, could demonstrate the clinical relevance of this finding intra-individually. In this study, myocardial perfusion images obtained after tracer injection down the infarct-related artery were compared with i.v. injection images in the same patients. The trial also provided us with the opportunity to compare the wall motion values calculated using conventional Tc-tetrofosmin gated single-photon emission computed tomography (SPECT) studies with those obtained using optimal target/background ratios after i.c. injection. METHODS: Fourteen patients with acute myocardial infarction, no history of previous cardiac events, single vessel disease and no visible collaterals in the coronary arteriogram were included in the study. Electrocardiogram gated SPECT was carried out separately after i.c. and i.v. injections of the tracer within 5-7 days following thrombolytic therapy. Myocardial perfusion patterns were compared by contingency table analysis after semi-quantitative visual scoring. Segmental wall motion was compared using quantified polar map data in a subset of patients (eight of 14) with normal to moderately hypoperfused myocardium supplied by the left coronary artery. RESULTS: Visual perfusion scores of both studies showed good concordance (kappa, 0.70), with complete agreement in 94 of 119 segments. Nearly all of the discordant segments (24 of 25) were mildly better scored in i.c. studies than in i.v. studies. The mean wall motion values calculated on polar maps of 78 segments for i.c. and i.v. studies were 8.4 +/- 1.2 mm and 8.2 +/- 1.3 mm (mean Delta wall motion=0.23 mm), respectively. High segmental wall motion correlation was observed (R=0.90; P<0.0001). CONCLUSION: It can be concluded that infarct-related myocardial perfusion scores obtained after i.c. and i.v. injections of Tc-tetrofosmin compare favourably, with a total agreement rate of 79%. However, the additional information obtained in 21% of the total number of myocardial segments by i.c. injection may indicate a mild underestimation of myocardial viability by i.v. injection. Conventional gated SPECT using i.v. Tc-tetrofosmin was demonstrated to be a reliable technique in the detection of true wall motion.

Arteries↗
PubMed2003

Comparison of gated planar Tc-99m tetrofosmin scintigraphy with radionuclide ventriculography and echocardiography in the evaluation of left ventricular wall motion.

Assessment of ventricular function is an important diagnostic and prognostic tool in coronary heart disease (CHD). The objective of this study was to compare radionuclide ventriculography (RVG), echocardiography (ECHO) and gated planar tetrofosmin myocardial scintigraphy (GPTF) in patients with CHD. Radionuclide ventriculography in left anterior oblique (LAO) and left lateral (LLT) projections was performed in 44 patients. Two days later, rest tetrofosmin perfusion tomoscintigraphy (SPECT) and rest GPTF in RVG identical parameters and projections were acquired. Within the two following days, the patients underwent two-dimensional ECHO. GPTF studies were processed and interpreted in original (NI-GPTF) and image inverted, RVG like form (I-GPTF). All visual interpretations were evaluated with a semi-quantitative scoring system. Quantitative analysis was performed on parametric images by means of segmental regions of interest. Linear regression and contingency analysis were carried out in overall analysis and on a segmental basis separately by accepting the RVG as the standard for the whole investigation. In overall cine-mode evaluation, NI-GPTF (r = 0.77, p < 0.001, complete agreement (CA) = 84%) was superior to I-GPTF (r = 0.73, p < 0.001, CA = 82%) and ECHO (r = 0.39, p < 0.001, CA = 78%), compared to RVG. On a segmental basis, NI-GPTF showed the best RVG-correlations except for inferoapical, mid-inferior, mid-anterior and anterobasal segments. In visual analysis of functional images, the best RVG-agreement was observed in I-GPTF (r = 0.72, p < 0.001, CA = 77%). On a segmental basis, I-GPTF showed the best RVG-correlations except for posterolateral, mid-inferior, mid-anterior and anterobasal segments. In overall quantitative evaluation, amplitude values in both I-GPTF (r = 0.76, p < 0.001) and NI-GPTF (r = 0.75, p < 0.001) studies were well correlated with RVG amplitude. I-GPTF gave the best RVG-correlation of phase (r = 0.59, p < 0.001). The mean phase and standard deviation RVG-correlations of I-GPTF were r = 0.92, p < 0.001 and r = 0.53, p < 0.001 respectively. In segmental quantification, amplitude values of all segments in I-GPTF were better RVG-correlated than in NI-GPTF. In conclusion, GPTF could be a time saving alternative to ECHO in the evaluation of wall motion by the nuclear medicine physician. Because of differing segmental RVG correlations, NI-GPTF and I-GPTF should be both interpreted to improve the diagnostic value of the method. Cine-mode and parametric image interpretations in GPTF studies should be done simultaneously since the former is more closely correlated to RVG.

Female↗
PubMed2002

Effect of O2-enriched breathing on myocardial uptake of 99mTc-sestamibi.

Oxygen (O(2)) inhalation after acute myocardial ischaemia has long been a part of standard therapy in cardiology. It has also been demonstrated that therapeutic hyperoxia diminishes myocardial stunning. The aim of this pilot study was to investigate whether the uptake kinetics of the myocardial perfusion agent technetium-99m sestamibi (MIBI) during O(2)-enriched breathing is modified in comparison with the kinetics observed under conventional rest imaging performed after injection during inhalation of room air. Nine patients scheduled for coronary intervention (CI) with a documented significant stenosis (> or =50%) of at least one epicardial coronary vessel and one patient with slow flow on coronary angiography were investigated. First, rest MIBI electrocardiogram-gated single-photon emission tomography (G-SPET) with 740 MBq was performed. Two days later, the tracer was injected following a 5-min period of 100% O(2)-supported (nasal catheter) breathing at rest (6 l/min) and a second G-SPET acquisition (O(2)+MIBI G-SPET) was carried out. Patients' medication was not withdrawn and was matched throughout the study. The mean elevation of arterial oxygen saturation achieved was 2.95%. No significant changes in arterial blood pressure or heart rate could be detected at any time during the procedure. Compared with the results of baseline G-SPET, on O(2)+MIBI G-SPET five patients scheduled for CI and the patient with slow flow showed increased tracer uptake in initially ischaemic regions without any alterations in other myocardial regions. In three of these five patients, post-CI imaging could be performed and showed increased tracer uptake in all additional areas detected previously by O(2)+MIBI imaging. In three patients, besides improvement in ischaemic regions, a mild reduction in tracer uptake was observed in myocardium that initially appeared normal. In one of these patients, thallium-201 rest-redistribution SPET was performed and showed an uptake pattern more similar to that seen on O(2)+MIBI images than that on baseline MIBI G-SPET. In one patient, no difference in tracer uptake was observed in pre- and post-CI studies. Improvement was detected in the wall thickening images of the O(2)+MIBI study in seven of the ten patients. Four of these patients showed improvement in the same regions after CI. In this pilot study, it was demonstrated that MIBI injection during O(2)-enriched breathing can be a useful technique for enhancing the detection of viable myocardial tissue. The possible mechanisms of altered tracer kinetics are discussed.

Aged↗
PubMedDate not supplied

Scintigraphic patterns in patients with subclinical hyperthyroidism.

The occurrence of suppressed thyroid stimulating hormone (TSH) levels in the presence of normal free thyroxine (fT4) and free triiodothyronine (fT3) is not rare. Although this entity may be defined as "subclinical hyperthyroidism", many patients presented with the above laboratory findings, suffer from non-specific signs and symptoms that could be related to hyperthyroidism. The aim of this study was to evaluate this entity using the standard method of radionuclide thyroid imaging by (99m)Tc-pertechnetate ((99m)TcO(4)(-)). Fifty-two patients (18 males; mean age: 45+/-9 years and 34 females; mean age: 43+/-11 years) with suppressed serum TSH levels and normal fT3 and fT4 levels, who were referred to our nuclear medicine department for thyroid scintigraphy were prospectively included in the study. Any thyroidal or non-thyroidal medication, thyroid surgery or non-thyroidal diseases constituted the main exclusion criteria. Thyroid scintigraphy was performed 15 min after the i.v. injection of 111 MBq (99m)TcO(4)(-) using a pinhole collimator. Scintigraphic findings were visually evaluated. All patients had normal serum levels of fT4 (mean value 1.53+/-0.14 ng/dl, normal range: 0.89-1.8 ng/dl) and fT3 (mean value 3.9+/-0.17 ng/dl, normal range: 2.3-4.2 ng/dl). Mean value of serum TSH levels was 0.09+/-0.12 microIU/ml (normal range: 0.35-5.5 microIU/ml). The above hormones were tested by the chemiluminescent method. Patients showed seven different scintigraphic patterns in their thyroid scintigrams as follows: hyperactive+hypoactive multinodular goiters, 27%; hyperactive multinodular goiters, 23%; hypoactive multinodular goiters, 15%; solitary hypoactive nodular glands, 14%; normal glands, 9%; solitary hyperactive nodular glands, 8%; and diffuse hyperactive glands, 4%. All but two patients (50/52 = 96%) showed mild to moderate hyperplasia of the thyroid gland. It is concluded that most patients with subclinical hyperthyroidism, (96%) show mild to moderate hyperplasia of the thyroid, and many (65%) show multinodularity with at least one hyperactive nodule.

Journal Article↗
PubMedDate not supplied

Cold infarction areas of varying size in the presence of left ventricular dysfunction: the impact on left ventricular ejection fraction determination by gated SPECT compared to radionuclide ventriculography.

The agreement in left ventricular (LV) ejection fraction (EF) determination between the gated perfusion SPECT (GPS) and radionuclide ventriculography (RVG) methods has been reported to show a systematic reduction with increasing EF values. In some reports, this EF difference exceeds 5%, indicating a critical underestimation rate by GPS in terms of clinical reliability. Although the accuracy of endocardial edge detection by means of GPS proves to be reliable, even in patients with large perfusion defects, the accuracy of EF calculation seems to depend on the level of individual EF values. Our objective was to investigate the RVG-GPS agreement in EF determination specifically in patients with myocardial infarction (MI) having perfusion defects including extremely depleted areas and LV dysfunction. Our patients had a EF<50%, a population in which the best agreement values between the above two methods should be found according to the literature. The idea was to test the accuracy of QGS algorithm in the presence of cold perfusion defects and a low probability of EF level influence. Thirty-six patients (26 males; 61.8+/-9.1 y and 10 female; 64.1+/-10.7 y) with MI older than two weeks, having perfusion defects, including all regions of varying size with no visible tracer uptake in rest GPS and RVG-EF<50% were included in the study. Rest-GPS was performed by injecting iv 925 MBq 99mTc-sestamibi (8-time bins) using a dual-headed gamma camera and rest-RVG was performed within the following three days by injecting iv 740 MBq 99mTc-pertechnetate-pyrophosphate (24 time bins). Myocardial perfusion was visually analyzed on a 17 segment-model and summed rest perfusion scores (SRS) were determined. The cold defect number (CDN) was calculated by selecting the myocardial segments with 0%-9% of maximal tracer uptake (grade 4) to identify the extent of the depleted tissue in each patient. The patients with (3)4 adjacent myocardial segments with grade 4 perfusion were considered as having large cold defects (Group 1: GR1). Patients with two or three CDN constituted the Group 2 (GR2; medium cold defects) and those with only one CDN constituted Group 3 (GR3; small cold defects). Hereafter, the relative weight of cold perfusion defects (CD%) and infarcted segments (IS%) were calculated for all patients and subgroups. Of 36 patients studied, 14 patients (39%, GR1) had large cold defects. Eleven patients (30.5%, GR2) had moderate and 11 (30.5%, GR3) had small cold defects. The overall mean value of CDN was 3.03+/-1.96 (1-9). Mean EF values in RVG and GPS among Groups 1, 2 and 3 were 28.78%+/-6.32%, 38.46%+/-6.43%, 38.73%+/-8.55% and 27.0%+/-6.93%, 37.82%+/-8.80%, 33.27%+/-11.65%, respectively. The percentage of patients showing an EF difference pound 5% between RVG and GPS in Groups 1, 2 and 3 were 93%, 73% and 27%, respectively. The CD% and IS% were 19+/-12, 30+/-7, 14+/-3, 6 and 52+/-20, 61+/-18, 50+/-17, 42+/-23 in overall, GR1, GR2 and GR3, respectively. It is concluded that: the negligible underestimation of EF in GR1 by GPS compared to RVG confirms the stability of the geometric modeling algorithm of QGS in this particular patient sub-group. Although the agreement results in patients with smaller defects were probably influenced through the realization of RVG and GPS studies performed on different days, it seems to be rational to set the threshold of RVG-GPS agreement dependency on EF levels in patients with myocardial infarction lower than 50%.

Female↗