Impaired lung epithelial permeability in hepatitis C virus antibody positive patients detected by 99mTc-DTPA aerosol scintigraphy

Chronic hepatitis C virus (HCV) infection has been recently identified as an aetiological agent in idiopathic pulmonary fibrosis. The present study was designed to determine the pulmonary clearance rate of 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) in asymptomatic HCV antibody positive (HCV Ab+) patients and the role of 99mTc-DTPA aerosol scintigraphy in the early detection of lung involvement. Twenty-six non-smoker HCV Ab+ and HCV-RNA (+) patients (20 female, six male; aged 43+/-11 years), with no clinical pulmonary symptoms, and normal radiological findings, were studied. Thirty-one healthy non-smoker volunteers (24 female, seven male; aged 40+/-10 years) were taken as a control group. 99mTc-DTPA aerosol inhalation scintigraphy and pulmonary function tests were performed in all patients and in controls. 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. The mean Kep values of healthy controls (0.78+/-0.13 for left lung, 0.79+/-0.14 for right lung) were significantly lower than HCV Ab+ patients (1.10+/-0.31 for left lung, 1.11+/-0.34 for right lung, P<0.001). But no significant change was observed in PFT (P>0.05). We conclude that subclinical alveolitis and/or interstitial lung disease may be present in patients with HCV Ab+, since it is known that an increase in the epithelial permeability of the lung is an early manifestation of interstitial disease.     

Dynamic pulmonary scintigraphy with Tc99m radioaerosol for the evaluation of the permeability of the alveolo-capillary barrier

Pulmonary clearance of small droplet 99mTc-DTPA radioaerosol was studied in 100 patients (12 normal subjects, N; 10 asymptomatic healthy smokers, FA; 31 patients with interstitial lung diseases, IP; 47 patients with chronic obstructive lung disease, BPCO). The first seven minutes of clearance were described with the function At = Ao*exp (-K*t) and the time constant K was considered representative of the 99mTc-DTPA clearance rate and hence of the alveolar-capillary barrier permeability. Groups FA, IP and BPCO showed a significant (p less than 0.05) or a highly significant (p less than 0.01) increase in permeability when compared to group N. No correlation was found between permeability and bronchial obstruction tests. The following conclusions were drawn: --99mTc-DTPA dynamic lung scanning is an easy, non-invasive method to assess derangements of alveolar-capillary barrier permeability secondary to epithelial damage; --permeability increase is a very early effect of cigarette smoke damage to the epithelium; --other mechanisms of epithelial injury are present in diffuse lung disease; --while the clinical role of this new pathophysiological test is not yet clear, it is likely that it may become a very early marker of pulmonary epithelial damage in diffuse lung disease.     

Urine excretion of inhaled technetium-99m-DTPA: an alternative method to assess lung epithelial transport

Technetium-99m DTPA clearance (99mTc-DTPA) clearance measured by a gamma camera or a scintillation probe not only reflects epithelial transport, but is also influenced by an unknown amount of mucociliary clearance depending on particle size and aerosol deposition. This is confirmed by factor analysis of dynamic inhalation studies. Assessment of epithelial absorption by urinary excretion of inhaled 99mTc-DTPA is largely independent of aerosol lung deposition. Twenty-four-hour excretion reflects the amount of aerosol cleared by absorption, while two-hour excretion is a quantitative measure of the aerosol absorption rate from the epithelium into blood. Urinary 99mTc-DTPA excretion of two aerosols with different particle size correlated significantly (p less than 0.001) with analysis of lung clearance curves. A very similar regression in the form of a cumulative exponential function was found with both aerosols. Two-hour urine values of nonsmokers differed significantly from those of smokers or patients with active interstitial or infectious lung disease. This alternative procedure is suited as a bedside test and holds promise for patient monitoring and follow-up.     

Detection of alveolar epithelial injury by<Superscript>99m</Superscript>Tc-DTPA radioaerosol inhalation lung scan following blunt chest trauma

DTPA clearance rate is a reliable index of alveolar epithelial permeability, and is a highly sensitive marker of pulmonary epithelial damage, even of mild degree. In this study, 99mTc-DTPA aerosol inhalation scintigraphy was used to assesss the pulmonary epithelial membrane permeability and to investigate the possible application of this permeability value as an indicator of early alveolar or interstitial changes in patients with blunt chest trauma. A total of 26 patients was chest trauma (4 female, 22 male, 31-80 yrs, mean age; 53+/-13 yrs) who were referred to the emergency department in our hospital participated in this tsudy. Technetium-99m diethylene triamine pentaacetic acid (DTPA) aerosol inhalation scintigraphy was performed on the first and thirtieth days after trauma. Clearance half times (T1/2) were calculated by placing a mono-exponential fit on the curves. Penetration index (PI) was calculated on the first-minute image. On the first day, mean T1/2 value of the whole lung was 63+/-19 minutes (min), and thirtieth day mean T1/2 value was 67+/-21 min. On the first day, mean PI values of the lung and 30th day mean PI value were 0.60+/-0.05, and 0.63+/-0.05, respectively. Significant changes were observed in radioaerosol clearance and penetration indices. Following chest trauma, clearance of 99mTc-DTPA increased owing to breakdown of the alveolar-capillary barrier. This increase in the epithelial permeability of the lung appears to be an early manifestation of lung disease that may lead to efficient therapy in the early phase.     

Technetium-99m-DTPA aerosol and gallium-67 scanning in pulmonary complications of human immunodeficiency virus infection.

We retrospectively compared the results of 67Ga chest scans and 99mTc-DTPA aerosol clearance measurements with those of fiberoptic bronchoscopy in 88 patients infected with the human immunodeficiency virus. Of 100 investigations, a pulmonary infection was diagnosed in 39, mainly Pneumocystis carinii pneumonia and a noninfectious disorder was found in 42, mainly Kaposi's sarcoma and lymphocytic alveolitis. Gallium scans and DTPA clearance were abnormal respectively in 74% and 92% of infectious complications, and in 12% and 60% of noninfectious disorders. In 10 cases, DTPA clearance was accelerated, while chest x-ray, arterial blood gases and even gallium scanning were normal. A value of DTPA clearance greater than 4.5%.min-1 was both sensitive and specific for the diagnosis of Pneumocystis carinii pneumonia. The gallium scan was always normal in bronchopulmonary Kaposi's sarcoma. We conclude that in symptomatic patients: (1) DTPA clearance measurements are useful for detecting lung disease when chest x-ray and/or PaO2 are normal and (2) a gallium scan is indicated to distinguish progressive Kaposi's sarcoma from a superimposed second process when radiological abnormalities of pulmonary Kaposi's sarcoma are present.     

Determining the influence of biocompatible oxygenators during cardiopulmonary bypass by 99m Tc-DTPA aerosol assessment of pulmonary permeability

Changes in pulmonary permeability provide a partial measure of the clinical impact of biocompatible oxygenator use during cardiopulmonary bypass surgery. Previous research has shown that the clearance rate of 99mTc-labelled diethylene triamine penta-acetic acid (99mTc-DTPA) aerosol from the lungs is increased following cardiopulmonary bypass, resulting from an increase in pulmonary permeability. The aerosol clearance rate has been shown to return to normal after a period of 7 days. A blind trial was set up to assess the clinical impact of a biocompatible, Trillium-coated oxygenator compared with a standard oxygenator. In a group of 25 patients 99mTc-DTPA aerosol studies were carried out prior to cardiopulmonary bypass surgery for mitral valve surgery. Repeat studies were undertaken 3-4 h and 24-28 h after surgery. Analysis of the rates of pulmonary clearance reproduced the trends seen in earlier research. There was however no statistically significant difference in the variation of serial clearance times between the groups of patients undergoing surgery using the Trillium-coated oxygenators and those using the standard oxygenators.     

Investigation of pulmonary epithelial permeability in patients after hyperbaric oxygen therapy by 99mTc diethylenetriaminepentaacetic acid aerosol inhalation lung scintigraphy

The aim of this study was to evaluate the possibility of pulmonary epithelial permeability damage in patients after hyperbaric oxygen therapy (HBOT) by 99mTc diethylenetriaminepentaacetic acid (99mTc-DTPA) aerosol inhalation lung scintigraphy. Twenty-five controls and 21 patients with normal chest X-rays and no cigarette smoking for at least 1 year were recruited for the study. 99mTc-DTPA aerosol inhalation lung scans were performed after 20 HBOT sessions in 21 patients with refractory osteomyelitis or diabetic foot. The HBOT with 100% oxygen at 2.5 atm absolute for 100 min was performed five times a week. Clearance rates (%/min) of 99mTc-DTPA aerosol in each lung field were calculated from the dynamic images for 30 min. Clearance rates of 99mTc-DTPA aerosol were compared between patients and controls by the unpaired t test. Thirteen patients who had 99mTc-DTPA aerosol lung scans before and after HBOT therapy studies were tested for statistical significance by using the paired t test. There was no statistically significant difference (P>0.05, unpaired t test) between patients and controls in every lung field. For the 13 patients who had 99mTc-DTPA aerosol studies both before and after 20 HBOT sessions, the results also showed no statistically significant difference (P>0.05, paired t test). It is concluded that there was no demonstrable pulmonary epithelial permeability change under current clinical HBOT protocol.     

Use of iodine-123 metaiodobenzylguanidine scintigraphy for the detection of amiodarone induced pulmonary toxicity in a rabbit model: A comparative study with technetium-99m diethyltriaminepenta acetic acid radioaerosol scintigraphy

The purpose of the study was; (i) to determine whether 123I-MIBG scintigraphy is sensitive for detection of amiodarone induced pulmonary toxicity (AIPT) and (ii) to compare it with 99mTc-DTPA radioaerosol. Twelve white New Zealand rabbit with initial mean body weight 4.24 +/- 0.47 g were divided into two groups. AIPT group (n = 7) was administered amiodarone (20 mg/kg BW). The control group (n = 5) received the same amount of 0.9% saline. All animals underwent 123I-MIBG and 99mTc-DTPA radioaerosol scintigraphy at the end of the treatment period. 123I-MIBG static thorax images were obtained during 10 minutes at 15 minutes and 3-hours after intravenous injection of the radiopharmaceutical. Lung to heart ratios (LHR) and lung to mediastinum ratios (LMR), and retention index (LRI) of 123I-MIBG were determined. Two days after 123I-MIBG scintigraphy, 99mTc-DTPA radioaerosol scintigraphy was performed, and clearance from the lungs was measured for 10 min (1 min/frame) following termination of inhalation. 123I-MIBG lung retention index (LRI) was significantly higher in the AIPT group than the control (61 +/- 4.6 vs. 40 +/- 4.5, p = 0.01). Early LHR and LMR were significantly lower in the AIPT group than in the control group (p = 0.04, p = 0.01, respectively), whereas those of late LHR and LMR were not significantly different. T1/2 values of DTPA clearance were significantly increased in AIPT group according to the control group (55 +/- 7.2 vs. 86.6 +/- 18.5, p = 0.02). 123I-MIBG scintigraphy is a valuable tool for detecting AIPT in a rabbit model. Additionally, 99mTc-DTPA radioaerosol scintigraphy is an excellent comprehensive investigational tool for detecting AIPT with the added advantage of lower cost.     

99mTc-DTPA clearance measured by a dual head gamma camera in healthy subjects and patients with sarcoidosis. Studies of reproducibility and relation to bronchoalveolar lavage findings

99mTc-DTPA clearance was studied in ten healthy non smokers, five asymptomatic smokers and nine non smoking patients with sarcoidosis in the supine position with a dual head gamma camera allowing simultaneous information of regional clearance rates in frontal and dorsal projections. In the patients with sarcoidosis, a bronchoalveolar lavage was performed prior to the clearance study. DTPA clearance rate was measured during 60-90 min and data were corrected for recirculating radioactivity. The coefficients of variation for measurements on 2 consecutive days in the 10 healthy non smokers were 9%-11% for the right and left lung, anterior and posterior projections. The T1/2 calculated from total lung projections were 90-92 min for the anterior view and 84-85 min for the posterior view. Regional measurements did not add further information. No apico-basal difference was found but there was a significant fronto-dorsal gradient in 99mTc-DTPA clearance in the supine position. Smokers had significantly (P less than 0.01) faster clearance rates (T1/2 28 +/- 10 min) than healthy controls. In the sarcoidosis group clearance rates were increased in four patients and no relationships were found between DTPA clearance rates and inflammatory markers (lymphocytes, albumin, ACE) in the bronchoalveolar lavage fluid.     

Tc-99m erythromycin lactobionate inhalation scintigraphy in parenchymal lung diseases

We have investigated Technetium 99m erythromycin lactobionate (Tc 99m EL) clearance from the lungs after inhalation, in the presence of an alveolitis. Eighteen patients (6 sarcoidosis, 7 idiopathic fibrosis, and 5 miliary tuberculosis) were imaged after the patients inhaled 1,110 MBq of Tc 99m EL. Clearance half time for the first 45 min, for 24 h, and retention at 24 h correlated with percentage of lymphocytes in bronchoalveolar lavage fluid (BAL) (r = .729, r = .883, and r = .826, respectively). There was a positive correlation between peripheral penetration (PP) and forced expiratory volume in 1 s (FEV1) (r = .806) and forced vital capacity (FVC) (r = .781). Retention was more marked in sarcoidosis compared with tuberculosis (0.025 < p < or = 0.05). Radioaerosol lung imaging may reflect the pulmonary function impairment in parenchymal lung diseases. Retention of Tc 99m EL may be related to number of BAL cells or presence of a lymphocytic alveolitis. Long residency time of Tc 99m EL in the lungs implies that erythromycin can also be administered by inhalation for therapeutic purposes.     

99mTc-DTPA and 99mTc-rhenium sulfur aerosol compared as adjuncts to perfusion scintigraphy in patients with suspected pulmonary embolism

Two radiopharmaceuticals, 99mTc-DTPA (D) and 99mTc-rhenium sulfur (R), were evaluated with a nebulizer delivering submicronic particles. Seventy-seven patients were examined (42 D, 35 R). For all patients, the examination began with a ventilation study. Immediately after the last ventilation view, 99mTc MAA was injected. Aerosol performance was assessed in 37 D and 17 R. Nebulization yield was 8.98% for D and 9.31% for R. A lung clearance study was performed in 12 patients for D and in 12 different patients for R. The lung clearance was 0.22%/min for R and 2.35%/min for D. The quality of ventilation and the quantification of bronchial and gastric activity were evaluated; the difference between the two groups was not statistically significant. It may be concluded that radioaerosols allow good quality images to be obtained. The yield of the nebulizer is adequate, so that nebulization of 20 mCi delivers approximately 2 mCi of aerosol activity to the lung. When pulmonary embolism is being investigated, R, due to its slower lung clearance, would appear to be preferable to D for patients suspected of increased bronchoalveolar permeability, especially if the time between nebulization and recording is greater than 10 min.     

SPECT images after intravenous injection of 99mTc-DTPA in lung tumors--comparison with delayed 123I-IMP lung scintigraphy

The aim of this study was to assess the efficacy of SPECT imaging of the thorax with 99mTc-DTPA, which accumulates at sites of increased capillary permeability and expanded extracellular space, by comparing it with delayed 123I-IMP lung scintigraphy. We have previously reported that increased uptake on delayed 123I-IMP lung scintigraphy was associated with atelectasis and inflammation. Thirteen patients with lung cancer (4 with atelectasis and 3 with pleurisy), one patient with malignant lymphoma complicated by pneumonia and pleurisy, and one patient with pneumonia were studied. 99mTc-DTPA scintigraphy was performed twice, 20-160 minutes and 2-4 hours after the intravenous administration of 370 MBq of 99mTc-DTPA. 123I-IMP scintigraphy was performed 24 hours after the intravenous injection of 111 MBq of 123I-IMP. SPECT images were obtained with both types of scintigraphy. 99mTc-DTPA scintigraphy was compared with 123I-IMP scintigraphy for its ability to detect atelectasis and pneumonia. All patients showed increased accumulation corresponding to the lesions on both 123I-IMP and 99mTc-DTPA scintigraphy. 123I-IMP scintigraphy showed a defect corresponding to the tumor with increased accumulation around the tumor, whereas 99mTc-DTPA scintigraphy showed accumulation corresponding to the tumor. Ten of 11 tumors showed accumulation of an intensity equal to that of the soft tissue of the chest wall on 20-60 min 99mTc-DTPA images. The 2-4 hr images showed that 99mTc-DTPA leaked from the periphery of the tumor toward its center. All the patients with pleurisy showed increased accumulation in effusion on 2-4 hr 99mTc-DTPA scintigraphy.(ABSTRACT TRUNCATED AT 250 WORDS)     

99mTc-DTPA gamma-camera renography: normal values and rapid determination of single-kidney glomerular filtration rate

A method for 99mTc-diethylenetriaminepentaacetate (DTPA) gamma-camera renography is presented. From each renogram, an uptake index (UI) proportional to the single-kidney glomerular filtration rate (SKGFR) is defined. If the proportionality factor between UI and SKGFR is the same in all patients, UI can be used as an accurate measure of SKGFR. In order to test this, 99mTc-DTPA renography was performed in 101 patients with glomerular filtration rates (GFR) varying between 4 and 172 ml/min. The sum of the right- and left-kidney UIs correlated well with the total GFR calculated from the simultaneously measured plasma clearance of 99mTc-DTPA after a single injection. The correlation coefficient was 0.97. The method was tested in a prospective study of 57 patients. The total GFR estimated from the renograms was not significantly different from the GFR calculated from the plasma clearance of 99mTc-DTPA. The coefficient of variation--a combination of inaccuracy and imprecision in the estimates as well as in the reference values-was 11.8% at a GFR of 100 ml/min. It is concluded that, in adults, the SKGFR can be calculated as part of the clinical routine from 99mTc-DTPA gamma-camera renography without determining the injected dose or collecting urine or blood samples. Normal values for some parameters of the renogram obtained in 25 normal subjects are given.     

肾小球滤过率评估方程在亲属肾移植供者评估中的适用性比较

目的以99mTc-DTPA血浆清除率为标准,对24 h内生肌酐清除率(Ccr)、Cockcroft-Gault(CG)方程和简化MDRD方程进行比较,评价三种方程在评估亲属肾移植供者肾功能中的应用价值。方法选择2004—2010年在我院进行评估的40例亲属肾移植供者,所有患者同步检测99mTc-GFR、血、尿肌酐等,将Ccr、C-G方程和简化MDRD方程估算的肾小球滤过率(GFR)用体表面积(BSA)标准化,与BSA标准化的99mTc-DTPA测得的GFR(99m Tc-GFR)进行比较。结果 Ccr、MDRD-GFR、CG-GFR与99mTc-GFR相关系数r分别为:0.74、0.81、0.86;三种方程的GFR估算值与99mTc-GFR差异均有显著统计学意义(P<0.01)。结论三种方程的GFR估算值与99mTc-GFR均有较好的相关性,其中以C-G方程最好,其次为简化MDRD方程,Ccr最低,但三种方程估算值与99mTc-GFR测定值差异均存在显著统计学意义。C-G方程较适合应用于亲属肾移植供者肾功能的初步评价。     

Pulmonary clearance of 99mTc-HMPAO aerosol

The clearance rate of inhaled aerosols of a lipophilic substance, 99mTc-HMPAO (Hexamethyl propylene amine oxime) was studied and compared to that of hydrophilic substances in 6 normal volunteers and 18 patients with lung diseases. The subject in sitting position inhaled a single deep breath of 99mTc-HMPAO aerosols, and held his breath about 30 sec. Then he continued to breath aerosols again for about 3 min. Radioactivity rapidly falls down during breath holding, to about 60% of the peak value (fast phase), with T 1/2 of 3.75 +/- 2.22 sec in 6 normal volunteers. This rapid phase was not appeared in hydrophilic aerosols with 99mTc-DTPA and 99mTc-pertechnetate and in lipophilic aerosol with 123I-IMP aerosol. The clearance of residual activity of 99mTc-HMPAO was slow with T 1/2 of 17.4 +/- 4.0 min. The T 1/2 of 99mTc-DTPA, 99mTc-pertechnetate and 123I-IMP were 50.2 +/- 20.9 min, 11.4 +/- 4.3, and 62.5 +/- 20.8 min respectively. 99mTc-HMPAO may cross transcellularly using the whole alveolar surface. The clearance of aerosols in the fast phase is rapid and depend on the regional perfusion. On the other hand, hydrophilic aerosol pass by an intercellular pathway and the clearance will be diffusion limited. As conclusion, inhalation study of 99mTc-HMPAO might be a new method to evaluate perfusion following ventilation study.     

Kit preparation of technetium-99m-mercaptoacetyltriglycine: analysis, biodistribution and comparison with technetium-99m-DTPA in patients with impaired renal function

Technetium-99m-mercaptoacetyltriglycine (99mTc-MAG3) was prepared by a frozen solution method, enabling the preparation of kits yielding a product substantially free of lipophilic impurities (96% 99mTc-MAG3). However, biliary activity was not completely eliminated as HPLC-purified 99mTc-MAG3 was also excreted by that route. Sequential 99mTc-DTPA and 99mTc-MAG3 renal scans were performed in 15 patients with renal dysfunction, including renal transplant recipients. In all cases, the 99mTc-MAG3 kit preparation provided superior images to 99mTc-DTPA at all levels of renal function due to a higher target-to-background ratio and a plasma clearance twice as fast as 99mTc-DTPA. Interpretation of delayed 99mTc-MAG3 images, however, was complicated by biliary excretion which will limit quantitative estimates of renal clearance. A 99mTc-MAG3 kit is likely to be of value in renal transplant assessment and in cases of significant renal impairment but would not appear to offer major advantages over 99mTc-DTPA in routine renal imaging.     

Evaluating the changes in alveolar permeability and lung ventilation in patients with chronic renal failure after haemodialysis using 99mTc-DTPA radioaerosol inhalation lung scan

Hypoxaemia occurring in patients with chronic renal failure (CRF) during haemodialysis (HD) has long been known. Several mechanisms of pathogenesis have been proposed. Before and after regular HD, lung ventilation (LV) and alveolar permeability (AP) were measured in 24 male patients with CRF (age, 61-75 years). LV and AP were determined by 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) radioaerosol inhalation lung scan (99mTc-DTPA lung scan). The LV images were visually interpreted according to established criteria, including the presence or absence of an inhomogeneous distribution, inverted base to apex gradient and segmental hypoventilation. The degree of AP in the total right lung was presented as the clearance rate (K; %.min-1) of the time-activity curve from dynamic total right lung images. Ten male normal controls (age, 62-76 years) were enrolled in the study for comparison. Ten of 24 (42%) cases showed an inhomogeneous distribution and eight of 24 (33%) cases showed hypoventilation on equilibrium LV images. After regular HD for 5 h, no significant changes in the LV images were found. Before HD, the CRF patient group (K=1.14+/-0.36%.min-1) had a significantly faster clearance rate than that of normal controls (0.75+/-0.14%.min-1, P<0.05). Moreover, the clearance rate after HD was significantly slower (0.87+/-0.15%.min-1, P<0.05) than that before HD. CRF can predispose patients to LV change and AP damage. After HD, the damage to AP is significantly improved. However, after HD, the change in LV is not significant.     

Different kinetics of lung clearance of technetium-99m labelled diethylene triamine penta-acetic acid in patients with sarcoidosis and smokers

The rate of clearance from the lungs of inhaled technetium-99m labelled diethylene triamine penta-acetic acid (^99mTc-DTPA) is often increased in interstitial lung disease as well as in smoking. In smokers a bi-exponential clearance course of ⁹⁹mTc-DTPA when measured over 3 h has previously been shown. This study was performed to compare the kinetics of clearance of ^99mTc-DTPA, measured for 3 h, in sarcoid patients and healthy smokers. Forty-one never-smoking patients with sarcoidosis and radiological signs of intrathoracic disease were studied. The results were compared with those of 16 healthy current smokers and of 14 healthy never-smokers reported previously. A mono-exponential clearance equation described the clearance in 22 of the sarcoid patients and all normal never-smokers, but with a shorter average tracer half-life in the patients (P<0.05). In 19 patients and all smokers a bi-exponential equation gave a significantly better curve fit. The rate of clearance of the slow component was higher in patients with sarcoidosis than in smokers (P< 0.05). The fraction of the tracer cleared by the fast clearance component was smaller in patients with sarcoidosis than in smokers (P<0.01). Differences in kinetics of clearance of ^99mTc-DTPA in sarcoidosis and smoking could thus be demonstrated, suggesting that the abnormal clearance is caused by diverging pathophysiological mechanisms.     

Pulmonary clearance of 99mTc-DTPA aerosol in patients with progressive systemic scleroderma]

Alveolar epithelial permeability was assessed in 32 patients with progressive systemic scleroderma (PSS), using 99mTc-DTPA aerosol. Immediately after the inhalation of 99mTc-DTPA aerosol for 3 to 6 minutes under normal tidal breathing, lung was imaged sequentially for 30 minutes from the posterior by a gamma camera and exponential fitting was processed on the time activity curve. T1/2 (min) was used as a parameter for the evaluation of permeability of alveolar epithelium. Patients with collagen disease showed shorter T1/2 (T1/2 = 43.7 +/- 23.8 min) than the normal volunteers (T1/2 = 76.8 +/- 8.7 min). No significant difference was observed between patients with or without interstitial changes on the chest CT. Significant correlation was not observed between T1/2 and %VC or %DLco. In 8 cases, studies were repeated in the interval of 3 to 19 months. Improvement of T1/2 was seen in 4 cases, independent of CT findings. These results suggest that 99mTc-DTPA aerosol clearance study provides information independent from other lung examinations, and may be useful for the assessment of lung interstitial changes in patients with PSS.     

The estimate of glomerular filtration rate during urography. Acceptability of a nonionic contrast medium as a marker of renal function.

RATIONALE AND OBJECTIVES. An estimate of glomerular filtration rate (GFR) may be obtained at the same time as urography by measuring the plasma clearance of the radiographic contrast medium using an x-ray fluorescence technique. It must be established whether the function measured or one modified by an effect of the contrast medium itself represents a true value. METHODS. Technetium 99m-DTPA (99mTc-DTPA) plasma clearance was measured in 21 patients using a single-injection technique, before, during, and after an intravenous injection of 50 mL of 350 mg I/mL iohexol. Iohexol clearance also was determined using an alternative single-injection, two-sample technique. RESULTS. The mean 99mTc-DTPA clearances before, during, and after contrast were 71.2, 71.5, and 70.7 mL/minute, respectively. The within-patient standard deviation in clearance values was 3.84 mL/minute. One factor repeat measures analysis of variance indicated no significant difference between the three measurements (F ratio = 0.24). Contrast and 99mTc-DTPA clearances performed simultaneously agreed closely (r = .976; ClDTPA = 1.02ClCon - 1.35). CONCLUSION. The authors conclude that no change in function is observed during or 48 hours after contrast injection. Imaging doses of iohexol can be used for GFR measurement during urography.