Accentuate the negative.
Rogers
L F
LF
D001706:Biopsy; D003937:Diagnosis, Differential; D006801:Humans; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed; D020246:Venous Thrombosis / Q000000981:diagnostic imaging*