Simultaneous whole body 18F-fluorodeoxyglucose positron emission tomography magnetic resonance imaging for evaluation of pediatric cancer: Preliminary experience and comparison with 18F-fluorodeoxyglucose positron emission tomography computed tomography

Table 1 Magnetic resonance imaging pulse sequences in pediatric whole body positron emission tomography-magnetic resonance imaging protocol

Pulse sequence	Plane	TR (ms)	TE (ms)	Thk/sp (mm)	Flip angle (°)	BW (Hz/Px)	FOV (cm)	Matrix	TA
T1 Dixon VIBE AC	Coronal	3.6	1.2	3/0	10	965	40-50	192 × 121	0:19
T1 VIBE	Axial	3.9	2.5	3/0	9	720	35-45	288 × 288	0:24
T2 HASTE FS	Axial	1600	95	5/0	9	710	30-40	320 × 260	1:08
EPI DWI	Axial	11000	70	6/0	N/A	2084	30-40	160 × 120	3:51
STIR	Coronal	4000	48	4/0	120	200	35-40	320 × 192	4:54

AC: Attenuation correction; TR: Repetition time; TE: Echo time; BW: Bandwidth; FOV: Field of view; TA: Acquisition time (per table position); VIBE: Volumetric interpolated breath hold examination; HASTE: Half-fourier acquisition single-shot turbo spin echo; FS: Fat suppression; EPI: Echo planar imaging; DWI: Diffusion weighted imaging; STIR: Short tau inversion recovery.

Table 2 Patients and diagnoses

Age at time of diagnosis	Sex	Diagnosis	Total number of PET-MRI examinations
13	Male	Gastrointestinal stromal tumor	3
19	Male	Undifferentiated small round cell sarcoma	1
12	Male	Rhabdomyosarcoma	1
18	Male	Non-Hodgkin’s lymphoma (follicular)	1
18	Male	Hodgkin’s lymphoma	1
19	Male	Non-Hodgkin’s lymphoma (large B-cell)	2
14	Female	Paraganglioma	1

PET-MRI: Positron emission tomography-magnetic resonance imaging.

Table 3 Comparative performance of positron emission tomography-magnetic resonance imaging maximum standardized uptake value and minimum apparent diffusion coefficient for lesion detection compared with positron emission tomography-computed tomography reference

Test characteristic	SUVmax > 2.5	ADCmin < 0.5 mm2/s	ADCmin < 1.0 mm2/s	ADCmin < 1.5 mm2/s
Accuracy	100%1	61.0%	68.3%	58.5%
Sensitivity	100%	28.6%	70.0%	100.0%
Specificity	100%	95.0%	66.7%	19.0%
Positive predictive value	100%	85.7%	66.7%	54.1%

¹Indicates statistical significance (P < 0.001, two-tailed McNemar’s test). ADCmin: Minimum apparent diffusion coefficient; SUVmax: Maximum standardized uptake value.