Abstract Archives of the RSNA, 2014
Priyanka Jha MBBS, Presenter: Nothing to Disclose
Giselle M. Melendres MD, Abstract Co-Author: Nothing to Disclose
Bijan Bijan MD, Abstract Co-Author: Nothing to Disclose
Eleanor Lee Ormsby MD, Abstract Co-Author: Nothing to Disclose
Lisa Lynn Chu MD, Abstract Co-Author: Nothing to Disclose
John P. McGahan MD, Abstract Co-Author: Patent agreement, Roper Industries, Inc
To evaluate detection of post-traumatic placental abruption in pregnant patients on contrast enhanced CT (CECT). Detection of placental abruption with CT vs US was compared. Strategies for optimizing detection of placental abruption on CT are discussed.
Our Level 1 trauma center’s PACS data was searched using keywords pregnancy, trauma &/or placental abruption over 10 years’ duration. Exclusion criteria were non-contrast imaging only. CT findings were compared to US,if performed within 24-hour interval. Total 36 patients, 1 with twin gestation,underwent CECT. Of these, 27 had US performed within 24 hours. 2 subspecialty-trained readers blindly reviewed CT and US images. Pregnancy outcome and placental features on delivery were used as reference standard. Lack of adverse pregnancy/fetal outcome was treated as absence of abruption.
There were 3 cases of complete & 8 cases of partial abruption. Both reviewers identified all partial and complete abruptions on CT. Sensitivity was 100% for both reviewers and specificity was 54.5% & 56.7%. Low specificity could partially be explained by small number of patients & contrast timing. Most of false positive reads were from normal placental structures such as cotyledons, venous lakes, age-related infarcts and marginal sinus of the placenta, misinterpreted as abruption. None of these had adverse fetal outcome. Placenta was most optimally evaluated on delayed phase imaging. On US, fetal demise was noted in all cases of complete abruption. No localized abruption demonstrated in cases of both partial and complete abruption.
Abruption is accurately identified on CECT with high sensitivity but low specificity. It’s crucial to avoid pitfalls from normal structures of cotyledons, venous lakes, age-related infarcts and marginal sinus, mimcking abruption. Contrast timing is important,with most optimal evaluation on delayed phases. If there is diagnostic dilemma on routine imaging and/or fetal monitoring abnornalities, low dose delayed imaging can be performed, with iterative reconstruction techniques,such as ASIR,while theoretically keeping the total radiation dose similar. US is a widely accepted but limited modality markedly underdiagnosing abruption.
CT has much higher sensitivity for detecting placental abruption than US. In cases of diagnostic dilemma, low dose (iterative reconstruction, e.g. ASIR) delayed phase imaging may be employed.
Assessing Accuracy of Detecting Post-traumatic Placental Abruption on Contrast-enhanced CT in Pregnant Women and Strategies for Optimizing Imaging of the Placenta. Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14016556.html