Table 1.

Quantitative comparisons of healthy anatomy reconstruction performance between UNA and state-of-the-art contrast-agnostic T1w synthesis models, using images with simulated pathology. PEPSI [34] is designed to emphasize the abnormalities, therefore we do not report its scores within diseased regions.

Modality	Method	L1 (↓)			PSNR (↑)			SSIM (↑)
		F	H	D	F	H	D	F	H	D
T1w MRI	SynthSR [23]	0.0285	0.0253	0.0010	20.71	22.90	36.59	0.823	0.879	0.895
	Brain–ID [33]	0.0231	0.0219	0.0007	22.86	23.71	40.22	0.859	0.890	0.904
	PEPSI [34]	0.0257	0.0194	N/A	21.78	23.21	N/A	0.831	0.872	N/A
	UNA	0.0147	0.0143	0.0003	31.98	33.25	45.61	0.981	0.992	0.998
T2w MRI	SynthSR [23]	0.0362	0.0337	0.0016	18.25	20.66	35.47	0.816	0.864	0.880
	Brain–ID [33]	0.0277	0.0269	0.0008	20.98	22.31	39.62	0.844	0.881	0.892
	PEPSI [34]	0.0295	0.0279	N/A	19.33	23.18	N/A	0.820	0.845	N/A
	UNA	0.0184	0.0182	0.0003	25.14	26.22	45.69	0.938	0.981	0.998
FLAIR MRI	SynthSR [23]	0.0327	0.0300	0.0016	19.30	21.04	34.88	0.823	0.869	0.895
	Brain–ID [33]	0.0285	0.0242	0.0010	19.98	20.32	38.76	0.840	0.879	0.907
	PEPSI [34]	0.0301	0.0287	N/A	19.82	21.59	N/A	0.842	0.850	N/A
	UNA	0.0202	0.0194	0.0007	28.34	28.93	42.91	0.921	0.982	0.996
CT	SynthSR [23]	0.0541	0.0536	0.0029	13.97	13.13	28.50	0.712	0.763	0.725
	Brain–ID [33]	0.0339	0.0357	0.0018	20.15	21.20	32.87	0.811	0.824	0.843
	PEPSI [34]	0.0473	0.0420	N/A	16.72	16.90	N/A	0.723	0.782	N/A
	UNA	0.0259	0.0266	0.0010	25.63	25.70	42.53	0.883	0.897	0.895

(F: full brain; H: healthy region; D: diseased region.)