Table 5.
A summary of articles focusing on ROI delineation methods for 23Na MRI in breasts
| First author, year [reference number] | Number of subjects (mean age, years) | Sodium coil / Scanner | ROI sampling method | Mean FGT total sodium concentration | Mean lesion total sodium concentration |
|---|---|---|---|---|---|
| Ouwerkerk, 2007 [5] | 22 patients; 3 with benign lesions and 19 with malignant lesions | Custom made bilateral phased array coil (NND, Medrad, Indianola, PA, USA) / 1.5 T (NND, General Electric Healthcare) | NR (ROI size 1,000−2,000 pixels) | Patients with cancer: 34 ± 13 mmol/kg | Benign tumours, 26 ± 5 mmol/L; malignant tumours, 53 ± 16 mmol/L |
| Jacobs, 2010 [7] | 18 patients (49 ± 8) | Custom made sodium coil / 1.5 T (NND, General Electric Healthcare) | NR (ROI size: 1,000−2,000 pixels) | NR |
Responders (n = 15): PreNACT 66 ± 18 mmol/L; PostNACT 48.4 ± 8 mmol/L (within 14 days after the 1st cycle) Non-responders (n = 3): PreNACT 52 ± 8 mmol/L; PostNACT 56 ± 2 mmol/L (within 14 days after the 1st cycle) |
| Jacobs, 2011 [19] | 6 patients (43.2 ± 12.5) | Custom made sodium coil / 1.5 T (NND, General Electric Medical Systems) | NR (ROI size: 1,000−2,000 pixels) | NR | PreNACT 55.2 mmol/L; PostNACT 45.0 mmol/L (7-8 days after the 1st cycle) |
| Zaric, 2016 [6] | 5 healthy volunteers (NRa) / 17 patients with cancer (56 ± 12) | Dual-tuned sodium and proton-tuned bilateral coil (QED) / 7 T (Magnetom; Siemens Healthineers) | Circular ROIs of no fixed size were placed on the solid parts of tumour while avoiding partial volume effect from fatty parenchyma and excluding cystic necrotic areas. ROIs of same size were defined in similar positions on the contralateral side in FGT |
Healthy volunteers: 36 ± 2 mmol/kg (Reader 1) and 37 ± 1 mmol/kg (Reader 2) Patients with cancer: 35 ± 3 mmol/kg |
Benign tumours: 47 ± 8 mmol/kg Malignant tumours: 69 ± 10 mmol/kg |
| Zaric, 2021 [8] | 3 healthy volunteers (NRa) / 15 patients with cancer (60 ± 10) | Dual-tuned sodium and proton-tuned bilateral coil (QED) / 7 T (Magnetom; Siemens Healthineers) | NR (ROIs covered the full cross-section of the tumour on at least three different sections) | 49.0 ± 3.0 mmol/L |
PreNACT: 70.6 ± 6.0 mmol/L PostNACT (patients with pCR): 60.9 ± 5.0 mmol/L (after one cycle) 49.1 ± 5.0 mmol/L (after two cycles) PostNACT (patients without pCR): 49.1 ± 5.0 mmol/L (after one cycle) 69.6 ± 9.0 mmol/L (after two cycles) |
| Current study | 9 healthy volunteers (38.2 ± 15.6) | Dual-tuned sodium and proton-tuned bilateral coil, (Rapid Biomedical) / 3 T (MR750, GE Healthcare) | Large ROI covering as much FGT as possible, small ROI with a fixed size (5 mm in diameter) covering the area with the highest sodium signal |
LROIb: 52.7 ± 18.6 mmol/L SROIb: 71.8 ± 25.5 mmol/L |
Not applicable |
FGT Fibroglandular tissue, NACT Neoadjuvant chemotherapy, NND Name not disclosed, NR Not reported, pCR Pathological complete response, ROI Region of interest
aMean age of eight volunteers recruited for both the sequence optimisation and three for B0 and B1 + inhomogeneity and partial volume effect study: 29 ± 5 years
bStatic magnetic field (B0), transmit radiofrequency field (B1 +) and partial volume-effect-corrected values