CT angiography of pulmonary embolism: diagnostic criteria and causes of misdiagnosis.
Computed tomographic (CT) pulmonary angiography is becoming the standard of care at many institutions for the evaluation of patients with suspected pulmonary embolism. This pathologic condition, whether acute or chronic, causes both partial and complete intraluminal filling defects, which should have a sharp interface with intravascular contrast material. In acute pulmonary embolism that manifests as complete arterial occlusion, the affected artery may be enlarged. Partial filling defects due to acute pulmonary embolism are often centrally located, but when eccentrically located they form acute angles with the vessel wall. Chronic pulmonary embolism can manifest as complete occlusive disease in vessels that are smaller than adjacent patent vessels. Other CT pulmonary angiographic findings in chronic pulmonary embolism include evidence of recanalization, webs or flaps, and partial filling defects that form obtuse angles with the vessel wall. Factors that cause misdiagnosis of pulmonary embolism may be patient related, technical, anatomic, or pathologic. The radiologist needs to determine the quality of a CT pulmonary angiographic study and whether pulmonary embolism is present. If the quality of the study is poor, the radiologist should identify which pulmonary arteries have been rendered indeterminate and whether additional imaging is necessary.
Wittram
Conrad
C
Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Founders Building 202, 55 Fruit St, Boston, MA 02114, USA. cwittram@partners.org
Maher
Michael M
MM
Yoo
Albert J
AJ
Kalra
Mannudeep K
MK
Shepard
Jo-Anne O
JA
McLoud
Theresa C
TC
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000792:Angiography / Q000379:methods* / Q000592:standards; D016477:Artifacts; D002408:Catheters, Indwelling; D003287:Contrast Media; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D004487:Edema / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000000981:diagnostic imaging; D009360:Neoplastic Cells, Circulating; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods / Q000592:standards; D014655:Vascular Resistance
D003287:Contrast Media