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Biomedical subjects

B Caner

Publications and source records attributed to B Caner.

At least 37 records · Page 2Linked to original sources
PubMed1998

Scintigraphic evaluation of healing response after heterograft usage for alveolar extraction cavity.

OBJECTIVE: Reconstruction of bone defects remains an important problem in oral and maxillofacial surgery. Restoration of defect sites with various grafting materials is a valuable approach to the solution of this problem. The aim of this study was to evaluate the effects of the use of heterografts on osteoblastic activity by means of a radionuclide technique. STUDY DESIGN: The postextraction alveolar cavities of impacted mandibular third molars on 22 patients were used as a healing model for this study. Granulated freeze-dried heterograft material of bovine origin was used on 11 patients; the other 11 patients constituted a control group. On each patient, three-phase bone scans were performed on postoperative days 7 and 28. RESULTS: Although dynamic and blood pool studies showed similar patterns with respect to the mean values of asymmetry ratios of operation sites to the contralateral sides for the 7th- and 28th-day scans, static-phase bone scans revealed that healing response through osteoinduction was more prominent in the study group than in the control group. A significant increase in the mean value of the ratio from the first scan to the second was observed on static images in the study group (first scan, 1.6 +/- 0.2; second scan, 2.0 +/- 0.5; p < 0.05). However, the same ratio failed to show any significant change in the control group (first scan, 1.5 +/- 0.2; second scan, 1.5 +/- 0.3; p > 0.05). CONCLUSION: Static-phase bone scintigraphy showed that when freeze-dried heterograft material is used to fill alveolar extraction cavities, it stimulates osteoblastic activity, which in turn leads to acceleration of the healing process and helps to maintain the linearity of bony structure. Moreover, radionuclide study can be used to evaluate the viability of freeze-dried heterografts in the 4th postoperative week, at which time no additional increase in perfusion resulting from surgical trauma was found in our series.

Alveolar Process↗
PubMed1998

Paradoxical hypotension during dobutamine infusion for myocardial perfusion scintigraphy.

AIM: Dobutamine as a predominant beta-1 agonist increases heart rate and myocardial contractility and at sufficient high doses, it also increases systolic blood pressure. This study was undertaken to describe instances of paradoxical hypotension during dobutamine infusion for TI-201 myocardial perfusion SPECT study and the relationship between scintigraphic findings and hypotension occurred during dobutamine infusion. METHODS: In 201 consecutive patients unable to perform adequate exercise, dobutamine TI-201 myocardial SPECT was performed. Dobutamine was infused starting from 10 micrograms/kg/min increasing to 40 micrograms/kg/min. Paradoxical hypotension was defined as a decrease in systolic blood pressure > or = 20 mmHg compared with baseline study. RESULTS: Paradoxical hypotension was observed in 40 patients (Group A) out of 201 (19.9%) while no significant change in systolic blood pressure was detected in the remaining 161 patients (Group B). Mean maximum fall in systolic blood pressure was 39 +/- 18 mmHg (range: 20-90). In 33 of 40 patients (83%) with paradoxical hypotension, scintigraphy was normal compared to 131 (81%) of the remaining 161 patients. In patients of Group A, angiography, echocardiography and tilt table tests were performed in 13, 11 and 6 patients respectively. Nine of 13 angiographic evaluations (69%), 10 of 11 echocardiographic evaluations (91%), all of the tilt table tests were normal. Additionally, all of the patients of Group A were clinically followed up at least 6 months after the myocardial perfusion scintigraphy. None of the patients had a cardiac event except one patient during the follow-up period. CONCLUSION: Paradoxical hypotension during dobutamine infusion for myocardial scintigraphy is not an uncommon finding and up to 19.9% patients may develop such hypotension. To maximize test safety, precautions should be taken during dobutamine myocardial stress test, since remarkable decrease in systolic blood pressure may occur. Unlike hypotension occurring with exercise test, hypotension response to dobutamine is not always a marker for coronary artery disease.

Adrenergic beta-Agonists↗
PubMed1997

Measurement of right ventricular ejection fraction by contrast echocardiography.

We evaluated 20 healthy subjects with no cardiac disease (8 males, 12 females, age 49+/-12) to determine the accuracy of right ventricular ejection fraction measurement with contrast echocardiography performed with D-galactose (Echovist 300). All patients underwent two dimensional echocardiography where the right ventricular ejection fraction was calculated by the Simpson's rule first without contrast, then after the injection of 5 ml D-galactose in the same position and compared to the right ventricular ejection fraction measured by the first pass radionuclide angiography on the same day. Subjects had a normal left ventricular ejection fraction of 66+/-5 and a body mass index of 28.9+/-1.2. The correlation between echocardiographic and radionuclide derived right ventricular ejection fraction significantly increased when contrast was used (r=0.81 vs. r=0.6). The r value for interobserver variability also increased significantly with contrast use (r=0.98 vs. r=0.7). We conclude that D-galactose contrast injection significantly enhances border detection and improves the accuracy of right ventricular ejection fraction calculations with echocardiography making it a simple and reliable method.

Adult↗
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

Comparison of 201Tl, 99Tcm-MIBI and 131I imaging in the follow-up of patients with well-differentiated thyroid carcinoma.

Problems stemming from the withdrawal of TSH suppressing doses of T4 or T3 and false-negative studies associated with 131I scintigraphy have justified the search for other radionuclides in the follow-up of patients with well-differentiated thyroid carcinoma. Although 201Tl and 99Tcm-MIBI (MIBI) have been suggested as alternatives, their role in the detection of residual and recurrent disease has yet to be established. We therefore studied 36 patients who had undergone total or near total thyroidectomy for well-differentiated thyroid carcinoma to determine the imaging potential of 201Tl, MIBI and 131I in the detection of residual or recurrent disease. Eighteen of the 36 patients had undergone 131I ablation. Imaging was performed 20 min following the intravenous injection of 111 MBq 201Tl or 555 MBq MIBI, or 48 h after the oral ingestion of 185 MBq 131I. The overall concordance between the 201Tl, MIBI and 131I scans was 70%. The concordance between thyroglobulin (TG) levels and the 131I scans was 78%; that between the 201Tl and MIBI scans and TG levels was 83%. Among the group of pre-ablative patients, there were six false-negative results with 201Tl and three false-negative results with MIBI. Among the post-ablation group, the 201Tl and MIBI scans were falsely negative in five patients. The 131I scans revealed all known residual or recurrent diseases. In conclusion, 201Tl, MIBI or TG levels should not be used in the place of 131I for the detection of residual or recurrent thyroid cancer. However, in patients who have not had their TSH suppressing doses of T4 or T3 withdrawn, the role of 201Tl and MIBI is debatable.

Adenocarcinoma, Follicular↗
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

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↗