Search PubMed⌕ Search

Biomedical subjects

H Durak

Publications and source records attributed to H Durak.

At least 55 records · Page 3Linked to original sources
PubMed1998

Technetium-99m-tetrofosmin scintigraphy in pulmonary tuberculosis.

UNLABELLED: Technetium-99m-tetrofosmin, an agent that is widely used in myocardial imaging, has been reported to accumulate in several types of malignancies, including lung tumors. Yet, there is limited knowledge about its role in imaging infection or inflammatory lesions. The aim of this study was to investigate the role of 99mTc-tetrofosmin scintigraphy in pulmonary tuberculosis in cases with active and inactive tuberculosis in comparison with radiological and microbiological findings. METHODS: Twenty-seven patients with active pulmonary tuberculosis (APTB) and 6 patients with inactive pulmonary tuberculosis (IPTB), proven by sputum smears and cultures, were included in this study. Mean age of the group was 42.6+/-13 yr. Nine months after therapy, 99mTc-tetrofosmin scintigraphy was repeated in 6 patients with APTB to evaluate response to therapy. Ten-minute anterior and posterior chest images were acquired 20 and 60 min after the injection of 370 MBq (10 mCi) 99mTc-tetrofosmin. The images were evaluated both visually and semiquantitatively by two blinded nuclear medicine physicians. For semiquantitative evaluation, regions of interest (ROIs) were drawn over the lesion (L) and nonlesion areas (NL). The mean count values of ROIs were obtained and L/NL ratios were calculated. RESULTS: According to the visual evaluations, 99mTc-tetrofosmin uptake was Grade (+) in 4 (15%) and Grade (++) in 23 (85%) patients with APTB. Technetium-99m-tetrofosmin uptake was negative in 5 patients with IPTB. Grade (+) 99mTc-tetrofosmin uptake was observed in only one inactive case. After therapy, there was no 99mTc-tetrofosmin uptake in 3 patients, which correlated well with chest radiography and clinical findings. In the other 2 patients, 99mTc-tetrofosmin uptake was slightly decreased when compared with a previous scan that correlated with radiological and clinical findings. In 1 patient with bilateral lung disease, 99mTc-tetrofosmin uptake decreased on the right lung lesions, whereas the left lung lesions persisted with no change. The mean early and delayed L/NL ratios of APTB were 1.53+/-0.22 and 1.45+/-0.21, respectively. Although 99mTc-tetrofosmin uptake in APTB lesions was more visually marked in early images than that in delayed images, there was no statistically significant difference between these two sets of images. CONCLUSION: Technetium-99m-tetrofosmin scintigraphy showed increased uptake in APTB lesions related to disease activity. After treatment, 99mTc-tetrofosmin uptake disappeared or decreased, correlating well with radiological and clinical findings. Technetium-99m-tetrofosmin scintigraphy may have a complementary role in the assessment of APTB as well as in follow-up treatment.

Adolescent↗
PubMed1996

Early and delayed thallium-201 scintigraphy in thyroid nodules: the relationship between early thallium-201 uptake and perfusion.

Seventy-six patients with thyroid nodules were studied. Initially, 74 MBq of thallium-201 was injected. The thyroid gland was imaged 15 min (early) and 3 h (delayed) after the injection. Thereafter, 185 MBq technetium-99m pertechnetate was injected. Immediately after the injection, a 1-min perfusion image was acquired, followed by an image at 20 min. Increased early and delayed 201Tl uptake compared with the contralateral thyroid tissue was adopted as the criterion for malignancy. Sensitivity, specificity and negative predictive values were found to be 85%, 64% and 78%, respectively, in operated patients, but these values were 86%, 87% and 95%, respectively, in the whole group, including patients followed with fine-needle aspiration biopsy. With the purpose of investigating the relationship between perfusion and early 201Tl uptake, both perfusion and early images were graded comparing nodular activity with contralateral thyroid activity. There was a poor correlation between perfusion and 201Tl uptake. The correlation was even worse in hyperactive nodules. It is concluded that early and delayed 201Tl imaging should not be used in the differential diagnosis of cold nodules and that early 201Tl uptake seems to be more closely related to factors other than perfusion.

Adolescent↗
PubMed1996

99mTc-MIBI scintigraphy in metastatic renal cell carcinoma: clinical validation of the relationship between 99mTc-MIBI uptake and P-glycoprotein expression in tumour tissue.

Technetium-99m hexakis-2-methoxyisobutylisonitrile (MIBI) and thallium-201 imaging was performed in a patient with metastatic renal cell carcinoma (RCC), which is a well-known tumour type demonstrating P1-glycoprotein (PGP) overexpression. Two scintigraphic patterns - Tl(+)/MIBI(-) in primary tumour and Tl(+)/MIBI(+) in metastatic tumour - were observed, suggesting high- and low-level PGP expression, respectively. Immunochemical study for PGP revealed strong staining of the primary tumour cells. This case clinically validates the previously suggested relationship between 99mTc-MIBI uptake and PGP expression.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Lung clearance of aerosolized 99mTc erythromycin lactobionate in rabbits.

In order to assess the lung clearance of aerosolized 99mTc Erythromycin Lactobionate (EL), 99mTc EL was administered to 9 New Zealand rabbits by inhalation. 5 rabbits inhaled cigarette smoke before 99mTc EL. Clearance half times were 3.0 +/- 0.9 hours in normals, 5.5 +/- 1.0 hours after smoke exposure. Clearance was not affected after destroying the surfactant layer. Slower clearance after smoke exposure may be due to the inhibition of mucociliary clearance. 99mTc EL can be considered as an alternative radioaerosol for ventilation imaging.

Administration, Inhalation↗
PubMed1996

Sublingual nitrate plus 99Tcm-tetrofosmin infusion in the detection of severely ischaemic but viable myocardium: a comparative study with stress, redistribution, reinjection and late redistribution 201Tl imaging.

To investigate the role of sublingual nitrate plus 99Tcm-tetrofosmin infusion in the detection of severely ischaemic but viable myocardium, we selected 25 patients with coronary artery disease who had at least one fixed segmental defect during conventional stress-redistribution (ST-RD) 201Tl single photon emission tomographic (SPET) imaging. Reinjection (RI) and 24 h late redistribution (LRD) imaging were also performed. Within a week of 201Tl imaging, one-day rest-stress (R-ST) 99Tcm-tetrofosmin SPET was performed with the same stress levels. The following day, 99Tcm-tetrofosmin was infused over 1 h immediately after sublingual nitrate administration and SPET images (N + Inf) were acquired. Of 100 fixed defects on R-ST 99Tcm-tetrofosmin imaging, 15 were reversible on N + Inf 99Tcm-tetrofosmin imaging. There was 91% concordance between ST-RD/RI/LRD 201Tl and R-ST/N + Inf 99Tcm-tetrofosmin imaging regarding reversibility. We conclude that N + Inf 99Tcm-tetrofosmin imaging may be clinically useful in the detection of severely ischaemic but viable myocardium.

Administration, Sublingual↗
PubMed1996

Lung clearance of inhaled 99Tcm-erythromycin lactobionate in non-smokers and smokers.

99Tcm-labelled erythromycin lactobionate (99Tcm-EL) was used as a radioaerosol for lung ventilation imaging in humans after animal studies had shown slow clearance of 99Tcm-EL from the alveolar spaces. We performed inhalation studies in 26 volunteers: 11 non-smokers, 13 smokers (3 of whom smoked one cigarette just before inhalation of 99Tcm-EL) and 2 patients with pulmonary emboli (PE). The PE patients were imaged by both 99Tcm-EL and xenon-133 (133Xe) for comparison. The image quality with 99Tcm-EL was comparable to that with 133Xe, showing good peripheral penetration. The biological clearance half-lifes for 99Tcm-EL were 3.9 +/- 1.1 h in the non-smokers, 5.9 +/- 2.2 h in the smokers and 9.8 +/- 6.6 h in the three subjects who smoked a cigarette just before inhalation of the aerosol. 99Tcm-EL was cleared more slowly in the smokers and after smoke exposure, which could have indicated alveolar macrophage uptake. 99Tcm-EL can be used as an alternative to 99Tcm-diethylenetriamine pentaacetate (99Tcm-DTPA) in ventilation imaging, thus overcoming the problem of the fast clearance of 99Tcm-DTPA in smokers.

Administration, Inhalation↗
PubMed1995

Somatostatin receptors in the orbits.

In-111 pentetreotide has been recommended for the detection of somatostatin receptor (SSR) positive tumors. Sites with increased numbers of activated lymphocytes may also show In-111 pentetreotide with Graves' ophthalmopathy (GO) compared to various other orbital disorders. Five patients with GO, three patients with necrotizing scleritis, and two patients with orbital pseudotumor were imaged at 4 hours, 24 hours, and 48 hours after injection of In-111 pentetreotide. Although planar images did not show considerable uptake, SPECT slices showed marked and persistent uptake in the orbits unilaterally in one patient, and bilaterally in three patients with GO. There was no significant correlation between the In-111 pentetreotide activity and the degree of opthalmopathy determined by Werner's classification. Pseudotumors also showed positive uptake. Early uptake was present in one patient with necrotizing scleritis because of Wegener's granulomatosis, and was completely diminished at 24 hours. Octreotide treatment in three patients with GO did not cause any clinical improvement. Although the presence of SSR, either on the infiltrated lymphocytes or on fibroblasts, implies that octreotide treatment for GO can be considered, the results are not encouraging. Nonspecific binding might be present when uptake patterns of orbits and persistence of activity during octreotide treatment are considered.

Adult↗
PubMed1995

Thallium-201 uptake in the orbits.

Thallium-201 uptake patterns in the orbits are not widely known. Diffuse, bilateral orbital localization of TI-201 chloride may be an incidental finding because of orbital muscle or other soft tissue uptake. Differences in orbital blood flow and soft tissue mass may be the cause of the varying uptake intensities in most cases. Focal uptakes, even when bilateral, may indicate specific pathology and should be investigated. Sample cases are presented.

Adult↗
PubMed1991

Tl-201 uptake in brown tumors of hyperparathyroidism.

Tl-201 chloride bone scans were performed on nine patients with primary hyperparathyroidism just after Tl-201 and Tc-99m parathyroid subtraction scintigraphy. Bone lesions accumulate Tl-201, especially in sites of brown tumor formation. This was proven by the histopathologic examination of two patients. Eight patients had bone scans with Tc-99m MDP. The lesion-to-background ratio was quantified in seven patients for Tl-201 and in four patients for Tc-99m MDP. Tl-201 uptake of the lesions were quantified in two patients. The lesion-to-background ratio was 1.63 +/- 0.21 and 2.51 +/- 0.88 for Tl-201 and Tc-99m MDP, respectively. A Ga-67 citrate scan was performed on one patient, and the lesion-to-background ratio was 1.49 +/- 0.06. The accumulation of Tl-201 in brown tumors of bone might be due to increased blood flow and local metabolic activity. Tl-201 chloride was inferior to Tc-99m MDP in lesion detection. It is concluded that bone imaging with Tl-201 can easily be performed following parathyroid subtraction scintigraphy to delineate the sites of brown tumor formation.

Adolescent↗
PubMed1991

Quantitative 99mTc-DTPA scintigraphy for determination of maxillary sinus drainage following Caldwell-Luc surgery.

Nine maxillary sinuses of 8 patients who had undergone Caldwell-Luc surgery (CWL) were injected with 100-125 microCi 99mTc-DTPA in 0.2 ml from the gingivo-buccal sulcus, passing through the canine fossa window. Sinus half-emptying times and percent contribution of the natural ostium (NO) and the naso-antral window (NA) to the clearance from the sinus were calculated, using time-activity curves as well as the activity of cotton wool plugs placed into the middle and lower conchae. Mean half-emptying times in patients in whom the mucosa had been removed were shorter than those in patients in whom it had been left in place. In the former group percent drainage through the NO was higher than that through the NA whereas in the latter group the opposite was the case. These findings are consistent with the thesis that if the mucosa is retained, the cilia continue their sweeping action towards the NO but if it is removed the NA gains importance in the drainage. This method is promising for the evaluation of maxillary sinus drainage following CWL.

Humans↗
PubMed1991

The utility of fractional wash-out slope values following intravenous 133Xe.

The regional clearance of 133Xe from the lungs after intravenous administration as well as following rebreathing was assessed in 7 normals and 18 patients with various lung disorders. Each lung was divided into three zones as upper, middle and lower. Regional ventilation (V) and regional perfusion (P) were determined using the area under the first peak at the beginning of the ventilation study and the area under the peak after intravenous administration, respectively. Slopes were calculated using the first exponential of the wash-out curve. Absolute slope values of the wash-out curves after perfusion (Pwo) and ventilation (Vwo) were expressed as a percentage of the total for each lung. Correlation coefficients between V and Vwo, V and Pwo, P and Pwo were .695, .584 and .882 in normals and .610, .461 and .685 in patients, respectively. It is concluded that Pwo is influenced by both perfusion and ventilation; it may reflect the fractional contribution to the gas exchange and can be used in the prediction of residual lung function after lung resection.

Administration, Inhalation↗