Abnormal uptake of Tc-99m MIBI, a novel myocardial imaging agent, in the lungs of patients with systemic sclerosis.
OBJECTIVE
Fibrosing alveolitis is a prominent feature of systemic sclerosis (SSc), and accounts for much of the morbidity and mortality of this disease. Sensitive techniques for the detection and monitoring of fibrosing alveolitis could target patients for early therapeutic intervention. The objective of this small pilot study was to assess the frequency and clinical significance of abnormal lung uptake of Tc-99m MIBI, a novel radionuclide imaging agent that selectively accumulates in cells rich in mitochondria.


METHODS
Sixteen patients with SSc and evidence of pulmonary involvement were studied. The uptake of radionuclide in the lungs, and the ratio of pulmonary to cardiac uptake were evaluated after intravenous injection of Tc-99m MIBI. Results were correlated with clinical and laboratory parameters.


RESULTS
Lung uptake of Tc-99m MIBI was increased in all 16 SSc patients compared to control patients with coronary heart disease but no evidence of pulmonary abnormality. The degree of isotope uptake in the lungs was correlated with the extent of maximal skin induration and with radiologic evidence of interstitial lung disease, but not with other clinical or laboratory parameters of disease activity or extent of pulmonary involvement. The ratio of pulmonary to cardiac uptake of isotope was also increased in patients with SSc compared to controls.


CONCLUSIONS
Accumulation of Tc-99m MIBI is abnormally elevated in the lungs of SSc patients with pulmonary involvement. Isotope accumulation in the lungs may be related to activation of fibroblasts or endothelial cells. The specificity and sensitivity of Tc-99m MIBI scanning in the detection and monitoring of pulmonary involvement, and its potential role in the management of SSc, deserve further investigation.
Richard
M
M
Department of Nuclear Medicine, Jefferson Medical College, Philadelphia, Pennsylvania, USA.
Cox
D
D
Earle
L
L
Varga
J
J
D003327:Coronary Disease / Q000000981:diagnostic imaging; D004417:Dyspnea / Q000503:physiopathology; D004730:Endothelium, Vascular / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D007275:Injections, Intravenous; D008168:Lung / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D017563:Lung Diseases, Interstitial / Q000000981:diagnostic imaging / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000378:metabolism; D010865:Pilot Projects; D011653:Pulmonary Diffusing Capacity / Q000502:physiology; D011658:Pulmonary Fibrosis / Q000000981:diagnostic imaging / Q000378:metabolism; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000493:pharmacokinetics; D012595:Scleroderma, Systemic / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi / Q000008:administration & dosage / Q000493:pharmacokinetics; D014109:Total Lung Capacity / Q000502:physiology; D014797:Vital Capacity / Q000502:physiology
D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi