Usefulness of contrast-enhanced T1-weighted sampling perfection with application-optimized contrasts by using different flip angle evolutions in detection of small brain metastasis at 3T MR imaging: comparison with magnetization-prepared rapid acquisition of gradient echo imaging.
OBJECTIVE
Early accurate diagnosis of brain metastases is crucial for a patient's prognosis. This study aimed to compare the conspicuity and detectability of small brain metastases between contrast-enhanced 3D fast spin-echo (sampling perfection with application-optimized contrasts by using different flip angle evolutions [SPACE]) and 3D gradient-echo (GE) T1-weighted (magnetization-prepared rapid acquisition of GE [MPRAGE]) images at 3T.


METHODS
Sixty-nine consecutive patients with suspected brain metastases were evaluated prospectively by using SPACE and MPRAGE on a 3T MR imaging system. After careful evaluation by 2 experienced neuroradiologists, 92 lesions from 16 patients were selected as brain metastases. We compared the shorter diameter, contrast rate (CR), and contrast-to-noise ratio (CNR) of each lesion. Diagnostic ability was compared by using receiver operating characteristic (ROC) analysis. Ten radiologists (5 neuroradiologists and 5 residents) participated in the reading.


RESULTS
The mean diameter was significantly larger by using SPACE than MPRAGE (mean, 4.5 +/- 3.7 versus 4.3 +/- 3.7 mm, P = .0014). The CR and CNR of SPACE (mean, 57.3 +/- 47.4%, 3.0 +/- 1.9, respectively) were significantly higher than those of MPRAGE (mean, 37.9 +/- 41.2%, 2.6 +/- 2.2; P < .0001, P = .04). The mean area under the ROC curve was significantly larger with SPACE than with MPRAGE (neuroradiologists, 0.99 versus 0.88, P = .013; residents, 0.99 versus 0.78, P = .0001).


CONCLUSIONS
Lesion detectability was significantly higher on SPACE than on MPRAGE, irrespective of the experience of the reader in neuroradiology. SPACE should be a promising diagnostic technique for assessing brain metastases.
Kato
Y
Y
Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, Sendai, Miyagi-ken, Japan. ykato@rad.med.tohoku.ac.jp
Higano
S
S
Tamura
H
H
Mugikura
S
S
Umetsu
A
A
Murata
T
T
Takahashi
S
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D003287:Contrast Media; D017352:Echo-Planar Imaging / Q000379:methods*; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D003287:Contrast Media; D019786:Gadolinium DTPA