Usefulness of the Delay Alternating with Nutation for Tailored Excitation Pulse with T1-Weighted Sampling Perfection with Application-Optimized Contrasts Using Different Flip Angle Evolution in the Detection of Cerebral Metastases: Comparison with MPRAGE Imaging

D. Kim; Y.J. Heo; H.W. Jeong; J.W. Baek; J.-Y. Han; J.Y. Lee; S.-C. Jin; H.J. Baek

doi:10.3174/ajnr.A6158

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Fig 1.
MR images of a 62-year-old male patient with lung cancer. Contrast-enhanced SPACE with DANTE (A) clearly shows a focal enhancing lesion in the left pons (arrow), but this is barely visible in MPRAGE (B). However, this lesion was accompanied by signal changes in the precontrast 2D T1-weighted (C) and FLAIR images (D) and an increase in size on follow-up MR imaging after 3 months (E).
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Fig 2.
MR images of a 54-year-old male patient with lung cancer. Contrast-enhanced SPACE with DANTE (A) clearly shows two enhancing lesions in the right parietal lobe (arrow and arrowhead). One enhancing lesion is clearly visible (arrow), but the other enhancing lesion at the posterior aspect (arrowhead) is poorly visible on MPRAGE (B). However, this lesion has increased (arrowhead) in size and shows increased enhancement on the follow-up MR imaging 3 months later (C).
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Fig 3.
Minute and faint enhancing lesions at the left frontal and occipital lobes were missed by observer 2 (A). A left frontal lesion also shows faint enhancement on sagittal and coronal reconstructed MPRAGE images (B and C). However, these enhancing lesions show more prominent enhancement on SPACE with DANTE (D) and increased size on the follow-up MR imaging (E) 4 months later.
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Fig 4.
Contrast-enhanced SPACE with DANTE (A and B) shows a focal, linear enhancing lesion in the right parietal lobe. However, we could easily recognize this as a false-positive finding caused by incomplete vessel suppression on MPRAGE images (C and D).
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Fig 5.
The CNR_{lesion/parenchyma} of SPACE with DANTE (8.62) (A) was higher than that of MPRAGE (3.49) (B).

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Table 1:

Comparison of lesion detectability according to lesion size

	SPACE with DANTE	MPRAGE	P Value
Lesion diameter ≤5 mm
Observer 1
No. of lesions^{^a}	328 (4.39 ± 7.54)	175 (2.96 ± 5.13)	.0006
Sensitivity (%)^{^b}	87.4	49.4
PPV (%)^{^b}	98.1	95.6
Observer 2
No. of lesions^{^a}	324 (4.50 ± 7.52)	150 (2.76 ± 5.20)	<.0001
Sensitivity (%)^{^b}	86.86	51.14
PPV (%)^{^b}	97.8	98.4
ICC^{^c}	0.99	0.98
Lesion diameter >5 mm
Observer 1
No. of lesions^{^a}	186 (2.62 ± 4.51)	168 (2.37 ± 3.52)	.0978
Sensitivity (%)^{^b}	94.74	85.79
PPV (%)^{^b}	96.77	97.02
Observer 2
No. of lesions^{^a}	188 (2.65 ± 4.37)	169 (2.38 ± 3.92)	.0531
Sensitivity (%)^{^b}	95.26	87.37
PPV (%)^{^b}	96.28	98.22
ICC^{^c}	0.99	0.98

Note:—ICC indicates intraclass correlation coefficient; PPV, positive predictive value.
↵a Data represent the number (mean). Values were compared using paired t tests.
↵b Values were calculated using a 2-way contingency table.
↵c Values were calculated using κ statistics.

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Table 2:

Comparison of FOM according to lesion size^{^a}

	SPACE with DANTE	MPRAGE	P Value
Lesion diameter ≤5 mm
Observer 1	0.904	0.698
Observer 2	0.861	0.702
Mean ± SD	0.882 ± 0.023	0.700 ± 0.038	.0017
Lesion diameter >5 mm
Observer 1	0.957	0.921
Observer 2	0.943	0.928
Mean ± SD	0.950 ± 0.013	0.925 ± 0.014	.1762

↵a Data for observers 1 and 2 are mean value of FOM data compared between SPACE with DANTE and MPRAGE.

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Table 3:
CNR_{lesion/parenchyma} and CNR_{white matter/gray matter} of SPACE with DANTE and MPRAGE^{^a}
SPACE with DANTE MPRAGE P Value
CNR (n = 51)
Lesion/parenchyma 52.3 ± 43.1 17.5 ± 19.3 <.0001
White matter/gray matter −0.65 ± 1.39 3.08 ± 1.39 <.0001
↵a Data are presented as means. Values were calculated using paired t tests.