Diagnostic performance of dedicated breast positron emission tomography

Abstract

Background: Dedicated breast positron emission tomography (dbPET) has been developed for detecting smaller breast cancer. We investigated the diagnostic performance of dbPET in patients with known breast cancer.

Methods: Eighty-two preoperative patients with breast cancer were included in the study (84 tumours: 11 ductal carcinomas in situ [DCIS], 73 invasive cancers). They underwent mammography (MMG), ultrasonography (US), and contrast-enhanced breast magnetic resonance imaging (MRI) before whole-body PET/MRI (WBPET/MRI) and dbPET. We evaluated the sensitivity of all modalities, and the association between the maximum standard uptake value (SUVmax) level and histopathological features.

Results: The sensitivities of MMG, US, MRI, WBPET/MRI and dbPET for all tumours were 81.2% (65/80), 98.8% (83/84), 98.6% (73/74), 86.9% (73/84), and 89.2% (75/84), respectively. For 11 DCIS and 22 small invasive cancers (≤ 2 cm), the sensitivity of dbPET (84.9%) tended to be higher than that of WBPET/MRI (69.7%) (p = 0.095). Seven tumours were detected by dbPET only, but not by WBPET/MRI. Five tumours were detected by only WBPET/MRI because of the blind area of dbPET detector, requiring a wider field of view. After making the mat of dbPET detector thinner, all 22 scanned tumours were depicted. The higher SUVmax of dbPET was significantly related to the negative oestrogen receptor status, higher nuclear grade, and higher Ki67 (p < 0.001).

Conclusions: The sensitivity of dbPET for early breast cancer was higher than that of WBPET/MRI. High SUVmax was related to aggressive features of tumours. Moreover, dbPET can be used for the diagnosis and oncological evaluation of breast cancer.

Keywords: Breast cancer; Dedicated breast positron emission tomography; F-18 fluorodeoxyglucose; Magnetic resonance imaging; Standardised uptake value; Whole-body positron emission tomography.

Fig. 1

Detection rate of dbPET and WBPET/MRI (n = 84). Five tumours were detected by WBPET/MRI only and were suspected to be in the blind area of dbPET. dbPET, dedicated breast positron emission tomography; WBPET/MRI, whole-body positron emission tomography/magnetic resonance imaging

Fig. 2

Reducing the blind area of dbPET. a Detachable 20-mm mat and dbPET detector. b Right image: a sagittal view of the dbPET scanner using a 20-mm mat. The distance from the limit end of the chest wall was 32 mm; left image: a sagittal view of the dbPET scanner using a 5-mm mat. The distance from the limit end of the chest wall was 43 mm. Reducing the mat thickness was effective in reducing the blind area close to the chest wall. dbPET, dedicated breast positron emission tomography

Fig. 3

A representative case. a Sagittal MRI image. The contrast-enhanced area showed the spread of the DCIS. b Sagittal dbPET images. These images presented the segmental FDG uptake (SUVmax, 4.08). The FDG uptake areas were similar to the contrast-enhanced area of (a). c Axial WBPET/MR image. The FDG uptake was very weak and, thus, it was difficult to determine the spread of DCIS. d Surgical specimen and pathological result; DCIS with 5- × 2.5-cm size (green-shaded area); ER, 90%; PR, < 5%; HER2, 2+; NG2; Ki67, 20%. MRI, magnetic resonance imaging (MRI); DCIS, ductal carcinoma in situ; dbPET, dedicated breast positron emission tomography; FDG, F-18 fluorodeoxyglucose; SUVmax, maximum standard uptake value; WBPET/MRI, whole-body positron emission tomography/magnetic resonance imaging; ER, oestrogen receptor; PgR, progesterone receptor; HER2, human epidermal growth factor 2; NG, nuclear grade