Infrared Spectroscopy in Differential Diagnosis of Pulmonary Embolism

The aim of the study was to assess the effectiveness of infrared spectroscopy for verification of pulmonary embolism (PE) and a number of similar diseases.

Infrared spectroscopy was used to investigate blood serum of 19 healthy volunteers and 30 patients with intraoperatively confirmed PE as well as with chronic obstructive pulmonary disease (COPD) (n=10), pneumonia (n=10), tuberculosis (n=10), lung abscess (n=10) and lung cancer (n=10), acute disorder of cerebral circulation (ADCC) (n=10), ischemic heart disease (IHD) (n=10). Peak height ratios of absorption band were taken as diagnostic parameters (cm^-1/сm^-1): P₁ - 1160/1165; P₂ - 1165/1070; P₃ - 1165/1150; P₄ - 1165/1050; P₅ - 1100/1050; P₆ - 1025/1165. These parameters of IR spectrum are significant for the given nosology.

The calculated indicators have demonstrated statistically significant difference of IR spectra parameters for the studied nosologies (p<0.001) even on the small samples supplementing each other and enabling step-by-step exclusion of lung abscess and pulmonary tuberculosis, COPD and pneumonia, cancer, IHD, ADCC, and PE.The presented radar charts, built with consideration of the values of all peak height ratios of the absorption bands with diagnostically significant maxima, provided the possibility to visualize the IR profiles making the differentiation of PE and its clinical analogs not only more objective and reliable but also more explicit and compelling.

Infrared spectroscopy is a potentially effective method of PE differential diagnosis. Sample expansion will allow researchers to evaluate the sensitivity and specificity of this technique compared to the existing standard schemes of PE verification.