Effect of silicone breast implants on myocardial imaging.

The authors investigated the effect of silicone breast implants (SBIs) on thallium-201 myocardial perfusion scintigraphy. Twenty-nine patients with SBIs and 14 control subjects were included in the study. All of the participants underwent a resting thallium-201 myocardial perfusion study. Comparison of the thallium images between patients with SBI and control subjects was done both visually and semiquantitatively. On visual analysis, neither image distortion nor image artifact attributable to the SBIs was noted. Semiquantitative analysis revealed that in patients with SBIs, the uptake values of the anteroseptal, anterolateral, lateroanterior, and lateroinferior myocardial walls was slightly, but significantly, lower than those of control subjects: anteroseptal, 87.7+/-6.0% vs. 92.8+/-5.1%; anterolateral, 88.0+/-5% vs. 92.6+/-4.5%; lateroanterior, 87.4+/-5% vs. 91.4+/-4.7%; and lateroinferior, 86.0+/-6.0% vs. 91.7+/-7.0%. The uptake value of the remaining walls in patients with SBIs were not significantly different than the control subjects. In conclusion, SBIs did cause a significant decrease in uptake values of the myocardial walls, which should be considered during interpretation of the images.

Measurement of blood flow by the 133Xe clearance technique to grafts of amnion used in vestibuloplasty.

The purpose of this study was to determine the blood supply to lyophilized amniotic membranes when used as graft material in vestibuloplasties. 133Xe clearance technique was used to measure the blood flow to the grafts. A total of 20 patients had either Clark (10) or Kazanjian (10) vestibuloplasties. The blood flow was determined at 2-3 days preoperatively and at 10 and 30 days postoperatively. The preoperative mandibular anterior alveolar mucosal blood flow was 34.4 +/- 10.7 and 23.1 +/- 13.1 ml/100 g/min for the Clark and Kazanjian groups, respectively. Ten days after vestibuloplasty operation with lyophilized amniotic membrane graft application the blood flow to the graft increased to 56.8 +/- 45.4 and 62.6 +/- 30.4 ml/100 g/min for the Clark and Kazanjian groups, respectively. The corresponding values at 30 days postoperatively were 24.6 +/- 10.2 and 22.2 +/- 9.2 ml/100 g/min, indicating the return to normal levels. The changes in blood flow as a function of time were statistically significant in each group (P<0.05). Our results demonstrated the angiogenic effect of lyophilized amniotic membranes until mucoid degeneration after 10-15 days.

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.

Evaluation of 99Tcm-labelled alpha-D-glucose 1-phosphate aerosols for SPECT ventilation lung imaging.

The purpose of the present investigation was to evaluate 99Tcm-labelled alpha-D-glucose 1-phosphate (GP) aerosols for single photon emission computed tomographic (SPECT) ventilation lung imaging in comparison to 99Tcm-diethylenetriaminepentaacetate (DTPA) aerosols. Ten normal nonsmoking male volunteers (aged 20-30 years) were included in this study after obtaining their informed consent. 99Tcm-GP, 30 mCi, in 2 ml was placed in the nebulizer (Venticis II) and inhalation continued for 5 min of normal breathing with oxygen flowing through. In 10 subjects dynamic images were obtained from the posterior position for 90 min with 45 frames on a 64 x 64 matrix by the use of a gamma camera. At the end of the dynamic study planar images of the lung (anterior, posterior and laterals) were recorded. Decay corrected clearance curves and kep values were obtained by the pulmonary epithelial programme and T1/2 values were calculated. The same procedure was followed by the use of 99Tcm-DTPA in the same subjects 2 weeks later. SPECT studies of the lung were performed in five subjects after inhalation of 99Tcm-GP aerosols. Clearance curves were monoexponential. The difference in T1/2 values between the right and left lungs was statistically insignificant (P > 0.10). The mean T1/2 values were 316.5 +/- 44.7 and 80.8 +/- 13.4 min for 99Tcm-GP and 99Tcm-DTPA, respectively. The difference was significant (P < 0.0005). On scintigraphic images 99Tcm-GP showed high alveolar deposition and low adhesion to major airways like 99Tcm-DTPA. However, it is preferred to 99Tcm-DTPA for SPECT studies because of its prolonged pulmonary clearance.

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.

Investigation of the effect of magnetic retention systems used in prostheses on buccal mucosal blood flow.

The purpose of this study was to investigate the probable effects of the magnetic field produced by dental magnets on neighboring capillary circulation. Ten subjects were used. Transparent acrylic resin devices were prepared to receive the dental magnets and were used continually by subjects except during sleep. The maxillary buccal mucosal blood flow was measured on both sides (control and experimental) in the same subjects before the use of dental magnets and after 3, 7, 15, 30, and 45 days by the 133Xe clearance technique. Upon analysis it was found that the difference in blood flow between the control and experimental sides was insignificant (P greater than .05). The decrease in blood flow as time progressed was attributed to the pressure exerted by the oral devices rather than by the effect of the magnetic field.

Diuretic renography in children: a non-invasive method for the assessment of upper urinary tract pathologies.

Thirty-eight kidneys from 20 children were studied with diuretic renography and the findings in 32 kidneys were compared with the results obtained using IVP. The diuretic renography findings were consistent with those of the IVP in 72 percent of the patients. The main disparity was the dilated nonobstructed pattern observed in the kidneys with normal IVP's, which is pointed out as being an asset of diuretic renography in revealing the functional status of kidneys. The sensitivity in detecting true obstruction was found to be 67 percent (4/6), and the specificity 95 percent (20/21). The accuracy of the technique was 85 percent with a false (+) rate of 5 percent (1/21) and false (-) rate of 33 percent (2/6). Diuretic renography is a simple, safe, non-invasive technique, easily applied to children with high specificity in excluding obstruction in a dilated renal pelvis.

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.

Effect of wearing complete dentures on human palatal mucosal blood flow measured by 133Xe clearance.

In eight edentulous subjects, who had not previously worn dentures, blood flow was measured by 133Xe clearance after intramucosal injection. Upper and lower complete dentures were then constructed for these subjects, and 133Xe clearance was measured after the dentures had been worn for 7 and 40 days. Before the insertion of dentures the mean blood flow to palatal mucosa was 18.9 +/- 7.1 ml/100 g/min. Seven and 40 days after wearing dentures the mean flows to the palatal mucosa were 10.6 +/- 4.5 and 12.6 +/- 5.3 ml/100 g/min, respectively. The difference before and after wearing dentures was statistically significant (p less than 0.05). The subjects were asked not to wear the dentures for 24 h after the third visit on the 40th day whereupon the blood flow reached almost normal levels (16.2 +/- 5.45 ml/100 g/min). The findings show that wearing dentures hinders the blood supply to the palatal mucosa, and that after resting the oral tissues, blood flow may return to normal levels.