Role of serial multiparametric magnetic resonance imaging in prostate cancer active surveillance

Table 1 Parameters of magnetic resonance imaging

Protocol	Sequence	Repetitiontime (ms)	Echo time(ms)	Flip angle	Slice thickness (mm)	Field of view	Matrixsize	Voxel size (mm × mm)	Reconstructed	Averages	Acquisition
				(°)		(AP × RL)			voxel size		time
						(mm × mm)			(mm × mm)		(min:s)
Sagittal T2-weighted	FSE	3000	100	90 exc.	5	160 × 160	224 × 216	0.71 × 0.74	0.63 × 0.63	6	3:42
	(18 echoes)			135 refoc.
T1-weighted	FSE	700	11	90 exc.	5	160 × 160	400 × 319	0.4 × 0.5	0.4 × 0.4	3	4:54
	(7 echoes)			145 refoc.
T2-weighted	FSE	3000	100	90 exc.	5	160 × 160	400 × 317	0.4 × 0.5	0.4 × 0.4	3	5:48
	(17 echoes)			145 refoc.
Diffusion weighted	Single-shot EPI	2500	64	90 exc.	4	160 × 144	80 × 59	2.00 × 2.42	1.25 × 1.24	61	4:02
					1 mm gap
dynamic contrast-enhanced	3D-FFE	4.4	2.1	15 exc.	5	260 × 260	128 × 102	2.03 × 2.52	1.02 × 1.02	2	6:37
T2 map	TSE	1300	N × 30	90 exc.	5	160 × 1602	160 × 160	1.00 × 1.25	0.63 × 0.63	2	10:323
	(6 echoes)			180 refoc.

¹Twelve averages were acquired for b = 500 s/mm².

²Field of view of 160 × 200 was used for larger patients to avoid fold over.

³Acquisition time was 13:08 min if the larger field of view of 160 × 200 was used. FSE: Fast spin echo; EPI: Echo planar imaging; FFE: Fast field echo; exc.: Excitation pulse; refoc.: Refocusing pulse; N: Echo number; AP × RL: Anterior posterior by right left.

Table 2 Qualitative determination of index of suspicion

Procedure step	Structure examined	Index of suspicion assessment
1	Assign region	Base	Superior most margin of prostate to the widest transverse diameter
		Midgland	Widest transverse diameter to ejaculatory ducts at verumontanum
		Apex	Inferior to midgland
2	Peripheral zone	Consider T2 features	4: Moderate low signal with mass like appearance
			3: Mild low signal with mass like appearance
			2: Mild low signal which is focal but not clearly mass like, moderate diffuse low signal
			1: Mild low signal, diffuse and/or feathered, linear low signal
			0: Normal signal
		Consider DWI features	4: Definite abnormality (high DWI and low ADC relative to background)
			3: Probable abnormality (low ADC)
			2: Possible abnormality (mild decrease ADC or increase DWI)
			1: Mottled
			0: Homogeneous ADC or low DWI
		Consider DCE features	4: Rapid early enhancement, wash out
			3: Rapid early enhancement, remaining strong and prolonged
			2: Mild early enhancement, plateau or progressive
			1: No early upstroke, progressive enhancement
			0: No enhancement
		Assign combined score
3	Central gland	Consider T2 features	4: Mass like low T2 signal with invasion into AFMS or peripheral zone/disrupted surgical capsule, irregularly or poorly marginated mass like low T2 signal without a capsule
			3: Mass like homogeneous low T2 signal with no capsule, preserved surgical capsule
			2: Diffuse heterogeneous signal with intact surgical capsule
			1: Encapsulated nodules
			0: Normal
4	Fibromuscular stroma	Assess for presence of disease
5	Extracapsular extension	Assess for presence of disease
6	Seminal vesicles	Assess for presence of disease

ADC: Apparent diffusion coefficient; DWI: Diffusion weighted imaging; DCE: Dynamic contrast-enhanced.

Table 3 Patient’s demographics and disease characteristics at baseline

Characteristic	Value
Age (yr), median (range)	65 (51-75)
PSA (ng/mL), median (range)	6.4 (1.4-14.3)
Clinical stage, n (% of total)
cT1c	20 (87.0)
cT2a	2 (8.7)
cT2b	1 (4.3)
Gleason score 6 (3 + 3), n (% of total)	23 (100%)
% of cores positive per patient, median (range)	8.3 (01-58.3)
Density of tumor in positive biopsy cores (% of core), median (range)	10 (1-60)
HGPIN, n (% of total)	6 (26.1)
PNI, n (% of total)	4 (17.4)
LVI, n (% of total)	0 (0.0)

¹Three patients had benign biopsies at study enrollment but previous positive biopsies. HGPIN: High grade prostate intraepithelial neoplasia; PNI: Perineural invasion; LVI: Lymphovascular invasion.

Table 4 Prostate cancer visualization with magnetic resonance imaging

	n = 23
Number of scans with baseline IOS of:
1	8
2	5
3	3
4	2
5	5
Number of follow-up MRI scans, median (range)	3 (0-4)
Number of follow-up scans with signs of disease progression	3
Number of follow-up scans with changed IOS	1

MRI: Magnetic resonance imaging; IOS: Index of suspicion.