Detection of cardiac myxomas with non-contrast chest CT.
BACKGROUND
Cardiac myxomas are sources of systemic embolism. Currently a large volume of chest CT and calcium-scoring CT scans are performed without contrast injection.


OBJECTIVE
To evaluate the diagnostic capability of non-contrast CT covering heart in detecting cardiac myxomas.


METHODS
This retrospective study included 36 non-contrast CT scans of 36 consecutive patients (16 men, 20 women) who underwent CT scan before surgery for left atrial myxomas and 20 patients without myxoma as a control group. Two independent readers who were blinded to medical information reviewed non-contrast CT scans of 36 patients with cardiac myxomas and 20 scans in the control group patients. They determined the presence of lesions suspicious of myxomas using a five-point scale. The other reader measured attenuation number in the non-calcific areas of the tumors and sizes of the masses on the non-contrast CT images.


RESULTS
The average attenuation of cardiac myxoma (22.5 Hounsfield units [HU]; range, 8.9-32.9 HU) and adjacent unopacified blood (44.6 HU; range, 31.5-57 HU) were significantly different (P < 0.001). Twelve cardiac myxomas (31.6%) had internal calcification and all of them were detected by both of readers. Cardiac myxomas were measured smaller on non-contrast CT (mean, 3.5 cm; range, 1.1-9.7 cm) than on pathologic specimens (mean, 4.1 cm, 1.4-10.0 cm) (P < 0.001). Considering grade 3-5 on a five-grade scale as the detectability, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of non-contrast CT in detecting cardiac myxomas were 88.8%/86.1%, 95.0%/100%, 96.9%/100%, 82.6%/80.0%, and 91.1%/91.1%, by reader 1 and reader 2, respectively and there was good inter-observer reliability (kappa value = 0.92, P = 0.157).


CONCLUSIONS
Non-contrast CT scan is useful for detecting cardiac myxomas. Therefore, radiologists should be familiar with imaging findings of cardiac myxomas on non-contrast CT.
Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Wonseon
W
Shin
Yeon Hyeon
YH
Choe
Sung Mok
SM
Kim
In-Young
IY
Song
Sam Soo
SS
Kim
D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D006338:Heart Neoplasms / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009232:Myxoma / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D013902:Radiography, Thoracic; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
Cardiac myxoma; non-contrast CT; screening