Pulmonary embolism: diagnosis with spiral CT and ventilation-perfusion scanning--correlation with pulmonary angiographic results or clinical outcome.
OBJECTIVE
To compare the accuracy of spiral computed tomography (CT) with that of ventilation-perfusion (V-P) scintigraphy in the diagnosis of pulmonary embolism (PE).


METHODS
Fifty-four patients in whom indeterminate V-P scans or discordant clinical and scintigraphic results were obtained underwent both V-P scanning and contrast material-enhanced spiral CT. The reference standard was pulmonary angiographic results in 26 patients (group I) or clinical outcome in 28 (group II).


RESULTS
Six (25%) of 24 group I patients had proved PE. The prospective sensitivity and specificity for segmental or subsegmental PE were 67% and 100%, respectively, and the positive and negative predictive values were 100% and 90%, respectively. In two group II patients, V-P scans had high probability for acute embolism, but spiral CT scans showed only chronic PE; in one patients, the V-P scan had low probability and the CT scan was positive for acute PE. An alternative CT diagnosis was established in four (31%) of 13 patients in whom a normal or low-probability V-P scan was obtained. Clinical outcome was consistent with spiral CT results in all cases.


CONCLUSIONS
Spiral CT has greater accuracy and specificity than V-P scanning in patients with an unresolved diagnosis and may be useful as the primary screening technique for PE.
Garg
K
K
Department of Radiology, University of Colorado Health Sciences Center, Denver, CO 80262, USA.
Welsh
C H
CH
Feyerabend
A J
AJ
Subber
S W
SW
Russ
P D
PD
Johnston
R J
RJ
Durham
J D
JD
Lynch
D A
DA
D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography; D015901:Angiography, Digital Subtraction; D002908:Chronic Disease; D003287:Contrast Media; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007472:Iohexol / Q000031:analogs & derivatives; D007482:Iothalamate Meglumine; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011336:Probability; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000188:drug therapy; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012015:Reference Standards; D012680:Sensitivity and Specificity; D013668:Technetium Tc 99m Aggregated Albumin; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome; D014692:Ventilation-Perfusion Ratio
D003287:Contrast Media; D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin; D007472:Iohexol; C038192:iopromide; D007482:Iothalamate Meglumine