Comparison of near-infrared spectroscopy with air plethysmography in detection of deep vein thrombosis.
BACKGROUND
As a noninvasive screening test, air plethysmography (APG) is a reliable and frequently used modality in the detection of deep vein thrombosis (DVT). Although APG is highly sensitive for the diagnosis of proximal DVT, its sensitivity for identifying calf DVT is poor. Near-infrared spectroscopy (NIRS) is a new modality which can be used to evaluate venous retention during walking. The purpose of this study was to investigate the diagnostic value of NIRS for the detection of DVT, particularly isolated calf DVT, in comparison with APG.


METHODS
Fifty limbs of 39 consecutive patients with clinically suspected DVT were studied. All patients were examined by venography and APG. Patients also underwent a treadmill-walking test with simultaneous NIRS. Deoxygenated hemoglobin was continuously measured by NIRS during exercise. The ambulatory venous retention index obtained from serial DeoHb changes was calculated in each patient.


RESULTS
Venography demonstrated DVT in 35 limbs, confined to the calf in 9 limbs, and with the involvement of a proximal deep vein with thrombi in 26. The overall sensitivity of NIRS and APG was 97% (34/35) and 80% (28/35), respectively. NIRS was more sensitive than APG for detecting isolated calf DVT (89% [8/9] and 22% [2/9], respectively), while both tests identified proximal DVT in all limbs.


CONCLUSIONS
NIRS is a highly sensitive method for the diagnosis of haemodynamically significant DVT. NIRS may become a useful screening test because of its reliability in detecting calf vein thrombi that cannot be identified by APG.
Hosoi
Y
Y
Department of Surgery, The University of Tokyo, Japan. hoshoi-1su@h.u-tokyo.ac.JP
Yasuhara
H
H
Miyata
T
T
Komiyama
T
T
Onozuka
A
A
Shigematsu
H
H
D005260:Female; D006801:Humans; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D010991:Plethysmography; D012680:Sensitivity and Specificity; D019265:Spectroscopy, Near-Infrared; D020246:Venous Thrombosis / Q000175:diagnosis*