Right lower lobe pulmonary embolus

Case contributed by Andrew Murphy


Right lower pleuritic chest pain

Patient Data

Age: 35 years
Gender: Male

Dual energy CT


The lateral basal segmental branch of the right lower lobe artery demonstrates a filling defect with, with the corresponding iodine map confirming. Consistent with a pulmonary embolism.

Suboptimal enhancement of the pulmonary trunk with an HU of 178. The monochromatic data set has increased the enhancement of the pulmonary trunk with an HU of > 200.

Case Discussion

The following case is a great example demonstrating the benefits of dual energy CT, in an earlier time scans that produce lower Hounsfied units over the pulmonary artery would require repeating until the scan was satisfactory.

Although this scan is borderline adequate, utilizing the monochromatic data set of 50 KeV has better demonstrated the contrast filled structures. The monochromatic energy is closer to the K-edge of iodine, and therefore iodine-enhanced structures will display better attenuation values.

Not every failed CTPA can be 'saved' using this method, yet it should be considered before re-scanning 1,2.

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