Pulmonary involvement in Behçet's disease: evaluation of 123 I-MIBG retention

The potential for early diagnosis of pulmonary arterial hypertension using lung iodine-123-metaiodobenzylguanidine (123I-MIBG) uptake: A case report

Previous reports have found evidence that the lung uptake of iodine-123-metaiodobenzylguanidine (¹²³I-MIBG) represents pulmonary vascular endothelial function. Therefore, it was believed that the reduced lung uptake of ¹²³I-MIBG in patients with pulmonary artery hypertension may indicate poor pulmonary vascular endothelial function in those patients. In our previous report, we analyzed the lung uptake of ¹²³I-MIBG in patients with pulmonary hypertension, and demonstrated that it is lower in patients with pulmonary arterial hypertension (PAH) than in those with chronic thromboembolic pulmonary hypertension and controls, suggesting that reduced uptake of ¹²³I-MIBG in patients with PAH indicates endothelial dysfunction of the pulmonary artery. In the current report, we describe a 46-year-old woman diagnosed with scleroderma whose lung uptake of ¹²³I-MIBG was decreased on admission, but she was not diagnosed with pulmonary artery hypertension at that time because her pulmonary artery pressure during right heart catheterization was not elevated. However, she was diagnosed with borderline PAH 2 years later. The lung uptake of ¹²³I-MIBG was reduced before a reduction in %DLCO was observed. This report suggests that the lung uptake of ¹²³I-MIBG may be useful for the early diagnosis of pulmonary artery hypertension.

Molecular imaging of the pulmonary circulation in health and disease

The pulmonary circulation, at the unique crossroads between the left and the right heart, is submitted to large physiologic hemodynamic variations and possesses numerous important metabolic functions mediated through its vast endothelial surface. There are many pathologic conditions that can directly or indirectly affect the pulmonary vasculature and modify its physiology and functions. Pulmonary hypertension, the end result of many of these affections, is unfortunately diagnosed too late in the disease process, meaning that there is a crying need for earlier diagnosis and surrogate markers of disease progression and regression. By targeting endothelial, medial and adventitial targets of the pulmonary vasculature, novel molecular imaging agents could provide early detection of physiologic and biologic perturbation in the pulmonary circulation. This review provides the rationale for the development of molecular imaging agents for the diagnosis and follow-up of disorders of the pulmonary circulation and discusses promising targets for SPECT and positron emission tomographic imaging.

Lung-uptake and -washout of MIBG in sarcoidosis

BACKGROUND

The aim of this study was to evaluate the uptake and -washout of I-123 meta-iodobenzylguanidine (MIBG), reflecting norepinephrine metabolism, in the lungs in patients with sarcoidosis.

METHODS

Lung I-123 MIBG kinetics was assessed in 43 patients with sarcoidosis. The range of disease duration was 1-16 years (median: 3 years). Thirteen patients had radiographic stage 0-I, 30 patients had radiographic stage II-IV. Serological clinical parameters and small fibre neuropathy, as assessed by temperature threshold testing (TTT) were measured in 39/43 patients. 31/39 patients had an abnormal TTT. Eleven healthy controls participated in this study. Both dual head planar and dual headed SPECT images of the thoracic regions were made. The uptake of I-123 MIBG and the washout percentage were calculated in sarcoidosis patients and compared with the healthy persons.

RESULTS

Lung I-123 MIBG uptake in patients with sarcoidosis did not differ from controls. The lung washout of I-123 MIBG was significantly (p<or=0.01) decreased in sarcoidosis. Remarkably this was most clearly seen in patients with an abnormal TTT and in patients with more advanced radiographic pulmonary involvement (radiographic stages II-IV) but not in patients with decreased lung function (FVC<80% or DLCO<80%).

CONCLUSION

The inflammatory process of the lungs in sarcoidosis seems not to affect pulmonary vasculature. In sarcoidosis decreased lung washout of I-123 MIBG might, at least partly, be explained by sympathetic autonomic nerve dysfunction. Future studies are needed to explore the clinical relevance of this observation.

Evaluation of pulmonary function and bicycle ergometry tests in patients with Behçet's disease

Behçet's disease (BD) has well-defined pulmonary complications, but cardiopulmonary exercise testing and the strength of the respiratory muscles have not been studied in detail. We aimed to investigate the pulmonary functions tests, inspiratory and expiratory muscle strength and endurance, cardiopulmonary exercise test response, and the relationship of these parameters in patients with BD. Forty BD patients and 20 healthy control subjects were recruited for this study. Mean age was 32.95 +/- 7.66 years for the BD group and 33.85 +/- 6.63 years for the control group with no statistically significant difference. The ratios of slight obstructive ventilatory impairment were 32.5% for the BD group. When the values of pulmonary function tests were compared, no statistically significant difference was found in FEV(1)/FVC (Forced expiratory volume during the first second/forced vital capacity), or maximal midexpiratory flow rate (all in percent) values between patient and control groups. Maximal inspiratory and expiratory pressures, peak expiratory flow rate (in percent) and maximal voluntary ventilation (in percent) values were significantly lower than those of the control group. Body's consumption of peak oxygen (VO(2peak)), oxygen consumption (milliliters per kilogram per minute), anaerobic threshold (AT), maximum exercise ventilation (VE(max)), work load values, and exercise test time in the bicycle exercise test were significantly higher in control groups than in patients with BD. The values of heart rate reserve, breathing reserve, and VE/VCO(2) at the AT of BD patients were within normal limits We conclude that respiratory and aerobic exercise may be recommended to improve respiratory muscle strength and endurance as well as the aerobic capacity and maximal ventilatory capacity in patients with BD.

Pulmonary vasculitis in behcet disease: a cumulative analysis

STUDY OBJECTIVES

The aims of this study were to investigate the frequency of pulmonary problems in Behçet disease (BD), and to discuss lesser-known features of pulmonary BD such as clinical characteristics, analysis of prognosis, and evaluation of treatment options with respect to the previously published cases.

DESIGN

We conducted a comprehensive review of the literature to analyze cumulated data about pulmonary involvement in BD.

SETTING

We found 159 articles regarding pulmonary disease associated with BD in May 2003.

PATIENTS

The evaluation of these articles demonstrated 598 pulmonary problems in 585 cases.

RESULTS

Pulmonary artery aneurysms (PAAs) are the most common pulmonary lesion in BD, and these are almost always associated with hemoptysis. Seventy-eight percent of patients with aneurysms have concomitant extrapulmonary venous thrombi or thrombophlebitis. Other pulmonary problems are reported in BD, and these are principally related to vascular lesions and radiologic abnormalities.

CONCLUSIONS

Pulmonary vascular problems, either PAA or involvement of small-sized vessels, are the main pulmonary disorders in BD. Immunopathologic findings indicate that the underlying pathogenesis is pulmonary vasculitis, which may result in thrombosis, infarction, hemorrhage, and PAA formation. Patients with small nonspecific radiologic abnormalities should be followed up closely since early diagnosis of vascular lesions may be life-saving. Immunosuppression is the main therapy for the treatment of a vasculitis. It is important that pulmonary angiitis is not mistaken for pulmonary thromboembolic disease since fatalities have occurred in BD shortly after initiation of anticoagulation/thrombolytic treatment.

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.

Involvement of pulmonary endothelial cell injury in the pathogenesis of pulmonary fibrosis: clinical assessment by 123I-MIBG lung scintigraphy

PURPOSE

Pulmonary microvascular endothelial injury may be involved in the pathogenesis of pulmonary fibrosis (PF). The aim of this study was to evaluate the pulmonary vascular status in patients with PF by lung scintigraphic assessment of 123I-metaiodobenzylguanidine (123I-MIBG), which reflects latent endothelial cell lesions.

METHODS

We assessed lung 123I-MIBG kinetics and clinical indices in 23 PF patients and 16 controls. Mean uptake ratios of lung to mediastinum (L/M) were calculated in anterior planar images at 30 (early image) and 270 (delayed image) min after intravenous injection of 123I-MIBG. The pulmonary mean washout rate (WR) of 123I-MIBG was also calculated.

RESULTS

The L/M ratio in early images, but not in delayed images, was significantly lower in the PF patients than in the controls (L/M(early) 1.41+/-0.14 vs 1.53+/-0.10, p<0.01; L/M(delayed) 1.28+/-0.10 vs 1.33+/-0.07, p=NS). WR was significantly reduced in the PF patients compared with the controls (28.6%+/-3.1% vs 34.2%+/-5.1%, p<0.001). In the study subjects (PF patients plus controls) there were significant relationships between lung WR of (123)I-MIBG and other diagnostic parameters for the severity of PF, such as vital capacity (r=0.625, p<0.0001), total lung capacity (r=0.691, p<0.0001), carbon monoxide diffusing capacity (r=0.622, p<0.0001), serum angiotensin-converting enzyme activity (r=0.422, p<0.01), carbohydrate antigen KL-6 levels (r=-0.495, p<0.01) and surfactant protein-D levels (r=-0.461, p<0.01). When control subjects were excluded, similar significant correlations were observed between WR and %TLC (r=0.508, p<0.05), DL(CO) (r=0.593, p<0.01) and serum ACE activity (r=0.515, p<0.05) in the PF patients.

CONCLUSION

These results suggest that endothelial cell injury plays a significant role in the pathogenesis of PF, and that lung WR of 123I-MIBG, which is a specific marker of endothelial damage, can serve as a novel diagnostic tool to evaluate the functional severity of PF.