CT alone or combined with ultrasound comparative in detecting PE

The combination of multislice computed tomography and D-dimer measurement was shown to be just as safe as using D-dimer followed by venous compression ultrasonography of the leg to rule out pulmonary embolism, according to recent study findings.

The researchers enrolled 1,819 consecutive outpatients with clinically suspected pulmonary embolism in the randomized, noninferiority trial. They compared clinical probability assessment and either D-dimer measurement and multislice CT (n=903) or D-dimer measurement, venous compression ultrasonography of the leg and multislice CT (n=916).

Any patient determined to have a negative work-up for pulmonary embolism but a high clinical probability in accordance with revised Geneva scores was further investigated.

The study’s primary outcome was three-month thromboembolic risk among patients untreated on the basis that their risk for pulmonary embolism could be ruled out by diagnostic strategy.

Pulmonary embolism prevalence was 20.6% for both strategy groups. The three-month thromboembolic risk was also similar between both groups at 0.3%.

The researchers concluded that both strategies were safe screening options, and that an ultrasound could be useful for patients with contraindications to CT. – by Cara Dickinson

Lancet. 2008;371:1343-1352.

This is a largely confirmatory study that fine-tunes the existing diagnostic algorithms. It is a well-conducted, large study, and the findings are compatible with outcomes from previous, similar studies, adding additional validity to these findings. Overall, this study represents an incremental step in the development of diagnostic algorithms for pulmonary embolism. It is also valid to point out that a clinical scoring system was used to determine the pre-test probability of pulmonary embolism. Although scoring systems like this are straightforward, they are not used in clinical practice as much as they should be.

– Nigel Key, MD

HemOnc Today Editorial Board member