Evaluation of D-dimer Test Correlation with Lung Perfusion-Ventilation Scan in Patients Suspected Pulmonary Embolism

Pulmonary embolism refers to the blockage of pulmonary arteries or a condition in which blood flow to the lungs is interrupted by a blood or fat clot. This phenomenon eventually leads to ische-mia and respiratory failure, which, without diagnosis and treatment, will result in the lungs losing their efficiency. Along with other diagnostic methods such as CT angiography and the D-dimer test, nuclear medicine scans are very helpful in embolism cases as a non-invasive diagnostic method. Specifically, the purpose of this study is to compare D-dimer tests with perfusion-ventilation scans in patients suspected of having pulmonary embo-lisms.

According to the Nuclear Medicine Association protocol, 112 patients underwent lung scintigraphy (V/Q) with SPECT imaging systems (Siemens Ecam models). D-dimer tests were admin-istered to all patients before the scan, at the discretion of the attending physician. Data were collected and the distribution of embolism probability (normal, low, high, and intermediate probabilities) among refer-ring patients was evaluated using Modified PIOPED criteria. In addition, D-dimer test values were evalu-ated and compared with possible pulmonary embolism diagnoses and clinical conditions (age, surgery, pregnancy, and underlying diseases).

This study showed that 26.2% of patients with normal V/Q and 15.4% of patients with V/Q with a low probability of embolism had positive D-dimer tests. Accordingly, patients with intermediate and high probabilities of pulmonary embolism had 33.3% and 50% positive D-dimer tests, respectively. Addi-tionally, the results of the studies showed that the correlation with D-dimers negative (positive) in individ-uals less than or equal to 60 years, who had a normal scan and a low, intermediate, or high embolism probability was 74% (26%), 92.3% (7.7%), 83.3% (16.7%), and 0% (100%) respectively. Over 60-year-olds showed the same correlation with 73.3% (26.7%), 76.9% (23.1%), 55.6% (44.4%), and 100% (0%) respectively.

A higher D-dimer level does not correspond to a positive pulmonary embolism finding on V/Q scans. Furthermore, according to the obtained results, high D-dimer values are significantly correlated with V/Q scan findings in patients less than or equal to 60 years old, but there is no significant statistical correlation between high D-dimer values in patients with surgery, underlying diseases and pregnant wom-en with V/Q scan findings