Table 1.

Results from photoacoustic imaging

P1	Fig.	Lesion type	Lesion size2 (mm)	PA	PA	PA size (mm)	Co-localization x-ray/MRI
	Nr.			lesion appearance	contrast
32		IDC	12	Mass	2.6	16	Good
35	4a-c	IDC	26	Mass	2.7	18	Good
36		IDC (3×)	6, 6, 20	Mass (3×)	4.2, 3.1, 3.3	8, 8, 11	Good
37		IDC	28	Ring	2.2	31	Good
38		IDC	19	Mass	5.1	19	Good
39		IDC	63	Non-mass	3.6	41	Reasonable
40		ILC	un	Non-mass	3.7	45	Poor3
42		IDC	un	Mass	3.9	28	Good
43		IDC	15	Mass	2.9	16	Good
44		IDC	25	Mass	3.7	38	Not defined
45		Adenotype	un	Non-mass	3.2	61	Reasonable3
47	4d-f	IDC	24	Ring	5.5	24	Good
494		LCIS	40	Non-mass	3.9	54	Good
52		IDC	un	Non-mass	2.7	53	Good
53		IDC	un	Ring	3.3	46	Good
54		IDC	22	Mass	6.4	18	Reasonable5
55		IDC	34	Mass	2.8	29	Good
56		IDC	22	Mass	3.4	11	Reasonable-Poor5
58	4j-l	ILC	22	Mass	2.3	19	Good
59		IDC	28	Non-mass	3.5	29	Reasonable
60		ILC	22	Not visible	1.06	0	n.a.
61		IDC	un	Mass, atypical	4.3	21	Good
62		IDC	18	Mass	2.6	15	Good
63		IDC	un	Mass	7.0	13	Poor5
65		IDC	18	Mass	2.6	13	Good
66	4g-i	MC	15	Mass	4.0	15	Good
67		IDC	13	Mass	5.3	16	Good
68		IDC	14	Mass	2.9	10	Good
70		IDC	19	Mass	3.0	23	Good
72		IDC	un	Non-mass	2.8	44	Good
73		IDC	25	Multifocal mass	2.9	42	Reasonable5

¹Internal numbering system

²The size of the lesion is estimated from histopathology post-surgery. If patients did not undergo surgery in Medisch Spectrum Twente (MST), the size is indicated as ‘unknown’ (un)

³The size of the lesion and/or the high breast density made a comparison between PA and x-ray lesion localization difficult

⁴An adenotype metastasis was found in one of the lymph nodes; however, the post-mastectomy specimen only revealed LCIS in the breast. The metastasis proves that there should have been an invasive component

⁵For these patients, the non-perfect co-localization could be attributed to the significant breast tilting during the PA measurement;

⁶The lesions with a contrast of ‘1’ for PA mammography were not visible in the PA imaging volume

PA photoacoustic, P patient number, MRI magnetic resonance imaging, IDC infiltrating ductal carcinoma, ILC infiltrating lobular carcinoma, LCIS lobular carcinoma in situ, MC mucinous carcinoma, n.a. not applicable, un unknown