Thrombus detection in the left atrial appendage using contrast-enhanced MRI: a pilot study.
OBJECTIVE
Left atrial thrombi are an important cause for embolism-related morbidity and mortality. Transesophageal echocardiography (TEE), the clinical reference, is semiinvasive; thus, we aimed to assess the value of contrast-enhanced cardiovascular MRI for the detection of thrombus in the left atrial appendage.


CONCLUSIONS
The image quality was good for both 2D perfusion (grade 4 +/- 1) and 3D turbo fast low-angle shot (FLASH) (grade 4 +/- 1, n.s.). Compared with TEE, 2D perfusion, 3D turboFLASH, and the combination of both techniques yielded sensitivities of 47/35/44%, specificities of 50/67/67%, positive predictive values of 73/75/80%, and negative predictive values of 25/27/29%, respectively. The size of the thrombus was overestimated by 2D perfusion (66%) and by 3D turboFLASH (25%) and agreement for location and shape of thrombus was 50% and 75% for 2D perfusion and 75% and 50% for 3D turboFLASH, respectively. The TEE thrombus size was significantly larger in patients with true-positive diagnoses by 2D perfusion (148%) and by 3D turboFLASH (151%) when compared with patients with false-negative diagnoses (p < 0.05 for both). No such difference was found for image quality, time delay between TEE and MRI examination, and location and shape of thrombi. Contrast-enhanced MRI lacks diagnostic accuracy for the detection of thrombi in the left atrial appendage. Future technical improvements are essential to establish this technique as a noninvasive alternative to TEE.
Mohrs
Oliver K
OK
Cardiovascular Center Bethanien (CCB), Im Pruefling 23, D-60389 Frankfurt/Main, Germany. o.mohrs@gmx.de
Nowak
Bernd
B
Petersen
Steffen E
SE
Welsner
Matthias
M
Rubel
Christine
C
Magedanz
Annett
A
Kauczor
Hans-Ulrich
HU
Voigtlaender
Thomas
T
D000368:Aged; D020517:Atrial Appendage; D003287:Contrast Media; D017548:Echocardiography, Transesophageal; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013927:Thrombosis / Q000175:diagnosis* / Q000000981:diagnostic imaging; D014743:Videotape Recording
D003287:Contrast Media; D019786:Gadolinium DTPA