Pulmonary Applications of Nuclear Medicine

[Additional utility of the ventilation scintigraphy and chest X-ray in the diagnosis of pulmonary thromboembolism]

AIM

To evaluate the utility of ventilation scintigraphy and chest X-ray in the assessment of the lung perfusion scintigraphy and to evaluate the utility of clinical findings in the diagnosis of pulmonary thromboembolism.

MATERIAL AND METHODS

A total of 100 patients who underwent a ventilation-perfusion scintigraphy due to suspicion of pulmonary thromboembolism were studied retrospectively. Three observers evaluated scintigraphic findings, blind to the other data on the patient. They consecutively added ventilation scintigraphy and chest X-ray to the perfusion study, making a consensus interpretation. Clinical findings were also evaluated. Sensitivity, specificity, positive and negative predictive values and global value test were calculated, using the final diagnosis presented by the patients on discharge as the gold standard. The Kappa statistics index was used to evaluate the degree of agreement between the three observers and the correlation between clinical and scintigraphic findings.

RESULTS

On adding the information of the ventilation to the perfusion study, specificity increased and sensitivity decreased. Kappa statistics between observers also increased. The chest X-ray did not significantly change the scintigraphic results. Little correlation was found between the clinical and scintigraphic findings, this association being greater in low probability studies.

CONCLUSIONS

We think that the performance of the ventilation study has great value in the interpretation of perfusion studies. The chest X-rays did not significantly change the scintigraphic results. Clinical data are important to establish pre-test probability and in their integration with the scintigraphy information.

Manifestations of scleroderma pulmonary disease

Scleroderma is a multisystem disease of unknown cause characterized by synthesis and deposition of excessive extracellular matrix and vascular anti-GBM antibodies, leading to pulmonary hemorrhage and glomerulonephritis with rapidly progressive renal insufficiency. Recent advances in the understanding of disease pathogenesis and diagnosis and treatment have significantly improved our ability to recognize the syndrome, distinguish it from other similar disorders, and offer successful treatment. This article focuses on the pathogenetic features, clinical manifestations, diagnostic strategies, and therapeutic principles of anti-GBM disease.

Comparison of thallium-201 and gallium-67 citrate scintigraphy in the diagnosis of pulmonary disease

Gallium is presently used in the diagnosis of inflammatory, granulomatous, and neoplastic lung disease despite its many logistical problems. In contrast, thallium-201 scintigraphy, which was initially developed for myocardial imaging, offers the principal advantage of immediate imaging and diagnosis although it had not been investigated previously for use in pulmonary disease. In this study, thallium and gallium were prospectively compared with each other for the diagnosis of a variety of lung diseases. The overall concordance rate was 75%. Thallium was found to be significantly more sensitive than gallium for the entire group studied (N = 51, p < 0.006). In a subset of patients in whom a firm diagnosis was established, thallium was also found to be more sensitive, 86% vs 64%. The greater sensitivity of thallium-201 and its several inherent advantages suggest that thallium-201 should replace gallium-67 citrate as the radioisotope of choice for nuclear imaging of the chest.

Incidence of pulmonary embolism in a chest hospital in Japan and importance of preoperative perfusion lung imaging in the diagnosis of postoperative pulmonary embolism

The incidence of pulmonary embolism was retrospectively studied in a University Chest Institute and its affiliated hospital in Sendai, Japan, whose annual numbers of discharged patients from chest medical wards and lung operations as a whole are about 600 and 400, respectively. Before 1975 there was no documented patient with pulmonary embolism. Since then 70 patients had been clinically suspected of having pulmonary embolism and 31 of the 70 were diagnosed as having pulmonary embolism; 15 without and 16 with surgical operations in the immediate past. Fourteen of the 31 patients required combined perfusion and aerosol inhalation lung imaging for diagnosis. Twelve postoperative patients could be diagnosed as pulmonary embolism by comparing postoperative perfusion lung images taken at the time of suspicion with preoperative perfusion counterparts. Although it is said to be rising, the incidence of pulmonary embolism in a chest hospital still seems to remain low compared with that in western countries. For postoperative patients, comparison with preoperative studies was found very useful in diagnosing postoperative pulmonary embolism. The importance of preoperative perfusion lung imaging cannot be overstressed not only as a preoperative lung function test but as a baseline study to be compared with postoperative perfusion images when pulmonary embolism is clinically suspected in postoperative patients.