- Seven studies that met inclusion and exclusion criteria were retrieved. They were systematic reviews (2), meta-analyses (2), prospective studies (2), and one retrospective review. Of these seven studies, four evaluated the accuracy of ultrasonography in detecting calf thrombosis and compared it to venography.
- The studies showed variable diagnostic characteristics for ultrasonography. - Sensitivity: Ranging from 13% to 100%. - Specificity: Ranging from 79% to 98%. - Positive predictive value: Ranging from 60% to 95%. - Negative predictive value: Ranging from 55% to 100%.
- There were significant methodological problems associated with the retrieved studies that included: - Variations in the study population or patient spectrum (symptomatic, asymptomatic, outpatients, inpatients). - Inadequate descriptions of patient spectrum, setting, and characteristics of study subjects. - Retrieval and publication biases: The keyword calf was not included in the search terms in the systematic reviews and meta-analyses. The literature search for the reviews was also limited to Medline database and there was hardly any attempt to identify unpublished articles. - Differences in the study design or review method across the retrieved articles.