Author(s): FarheenRazvi *, Taranpreet Singh Kocchar , Tejas Kumar Mansukhlal Sejani , Gao Jian Bo
Pulmonary embolism is a frequent cause of mortality and morbidity.
Aim of this study was to evaluate the utility of spiral computed tomographic angiogra-
phy in determining the prevalence of pulmonary embolism in a clinically suspicious
group and to assess the image quality of a single source computed tomography in
diagnosis of pulmonary embolism. We have also investigated the reliability of D-dimer
test in ruling out pulmonary embolism.
Image quality, was assessed by analyzing the attenuation in the pulmonary trunk and its
branches in comparison with the background noise. Mean attenuation values and
standard deviation were recorded and displayed in Hounsfield Units. The computed
tomography values, standard deviation values and signal-noise ratio obtained were then
statistically analyzed using SPSS 17.0 software.
D-dimer test results were also obtained for the patients suspected of pulmonary
embolism using rapid D-dimer testing and a reference range of 0 – 0.3 μg/l was consid-
ered as normal.
Results:
Spiral computed tomography was a valuable method for identifying 20
patients with pulmonary embolism (sensitivity, 100%). It could correctly exclude
pulmonary embolism in 28 out of 30 non - pulmonary embolism cases yielding a
specificity of 94%.In 10 of the 20 patients devoid of pulmonary embolism; Spiral
computed tomography provided an alternate clinical diagnosis. In the remaining 10
patients, spiral computed tomographic angiography scans were normal. The statistical
analysis of the computed tomography values standard deviation and signal-noise ratio
of the pulmonary trunk and pulmonary artery (without right or left predilection)
showed a p-value>0.05. D-dimer Test showed elevated levels in 18 patients who were
diagnosed with pulmonary embolism on spiral computed tomography scans. 8 patients
without pulmonary embolism on spiral computed tomography scans also showed elevat-
ed D-dimer levels. The remaining 22 patients had normal D-dimer levels.
Conclusion:
Spiral computed tomography has a good sensitivity and specificity for the
diagnosis of pulmonary embolism. In the majority of patients who did not have pulmo-
nary embolism, it provided important ancillary information for the final diagnosis.
Therefore, combining Spiral computed tomography scan with a D-dimer Test is more
effective in the accurate diagnosis of pulmonary embolism