CT technique detects more post-TKA thrombosis than traditional methods
MedWire News: Multislice computed tomography (MSCT) is more sensitive than conventional techniques for the detection of deep vein thrombosis (DVT) and pulmonary arterial thrombosis (PAT) in patients who have undergone total knee arthroplasty (TKA), study findings indicate.
Pulmonary angiography and ventilation perfusion (VP) lung scintigram have traditionally been used to detect PAT, explain Nobusada Funabashi (Chiba University Graduate School of Medicine, Japan) and colleagues.
"Recently, MSCT has been shown to detect PAT accurately and has become the first-line examination for diagnosing [the condition]," they add.
Funabashi and team compared MSCT with VP lung scintigram and ultrasonography of the lower extremities to determine which method was most accurate for the diagnosis of new cases of PAT and DVT in 25 patients (80% women) who had undergone TKA.
All patients underwent testing before and 7 days after TKA, and all received postsurgery anticoagulation with warfarin.
PAT and DVT were detected in two patients by MSCT prior to surgery.
In the remaining 23 patients, seven (30.4%) had asymptomatic PAT detected by post-TKA MSCT, compared with only two (8.7%) cases detected on VP lung scintigram, an inter-group difference that was of borderline significance.
The post-TKA MSCT scan indicated that six (26.1%) patients had DVT, whereas ultrasonography detected blood flow abnormality in just four (17.4%) patients.
Of note, none of the patients with negative post-TKA MSCT findings had evidence of PAT or DVT when screened with a VP lung scintigram or ultrasound scan, respectively.
Writing in the International Journal of Cardiology, Funabashi and co-authors suggest that "the superiority of MSCT over the other two techniques examined might be due to its ability to detect thrombi that do not interfere with blood flow."
Another advantage of MSCT is its ability to simultaneously detect PAT and DVT.
However, a disadvantage of the technique is that contrast material is required and patients are exposed to radiation. "This should be taken into account by physicians," the researchers remark.
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By Laura Dean