Synthetic MRI in Neurofibromatosis Type 1

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FIG 1.
Synthetic T2-weighted (A) and FLAIR (B) images show FASI in the left lentiform nucleus, right globus pallidus, and bilateral thalami, accurately, as shown on the conventional T2-weighted (C) and FLAIR (D) images. T2-weighted image (E) in an HC shows no lesion in the peri-dentate area. However, a hyperintensity is seen in the corresponding area on synthetic T2-weighted image (F, arrows), an artifact probably due to CSF flow.
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FIG 2.
Myelin (A and B), WM (C), and GM (D) maps of a patient with NF-1. FASI in the left lentiform nucleus (A, red ROI) show prominently decreased R1, R2, PD, MyC, and MyCvol values compared with the normal right side (B, red ROI). The WM map (C) does not assign as the FASI; however, GM map (D) signs the FASI as GM.

Table 1:

cMRI versus SyMRI and interobserver agreement for FASI detection^{^a}

	cMRI vs SyMRI (Ob1)	cMRI vs SyMRI (Ob2)	İnterobserver Agreement on SyMRI	İnterobserver Agreement on cMRI
Thalami	0.9	0.86	0.82	0.94
WM (centrum semiovale)	1	1	1	1
BG	1	1	1	1
Pons	1	0.94	0.9	0.98
Mesencephalon	1	0.92	0.9	0.94
Cerebellum and MCP	0.85	0.84	0.80	0.90
Peridentate area	0.56	0.72	0.65	0.82

Note:—Ob indicates observer; BG, basal ganglia; MCP, middle cerebellar peduncle.
↵a Weighted κ analysis.

Table 2:

Comparison of SyMRI parameters of patients with NF-1 and healthy controls

Variables	Healthy Controls		NF-1		P Value^{^a}
Variables	Mean	SD	Mean	SD	P Value^{^a}
BPV (mL)	1279	109.64	1390	131.23	.035^{^b}
ICV (mL)	1401	120.16	1510	138.67	.035^{^b}
WM (mL)	396.20	66.78	419.88	48.83	.286
GM (mL)	862.93	82.29	949.16	89.15	.028^{^b}
MY (mL)	107.96	14.37	129.27	17.25	.067
%MY/BPV	8.53	0.85	8.51	0.80	.933
%GM/ICV	61.72	4.65	62.26	2.02	.763
%MY/ICV	7.80	0.82	7.87	0.82	.832
R GP R2^{^c}	14.49	1.02	13.66	1.31	.062
R CN R2	12.15	0.38	11.82	0.52	.058
L CN R2	12.12	0.37	11.74	0.56	.042^{^b}
R thalamus R2	12.74	0.39	12.34	0.52	.035^{^b}
L thalamus R2	12.69	0.38	12.28	0.51	.035^{^b}
Pons MyV (mL)	21.96	3.01	18.54	3.73	.028^{^b}

Note:—GP indicates globus palladium; CN, caudate nucleus; R, right; L, left.
↵a Independent-samples t test; adjusted P value was obtained using the Benjamini-Hochberg method.
↵b Significance is <.05.
↵c R2 unit is s-1.

Table 3:

ROI analysis of FASI and normal-appearing WM on MYC, GM, and WM maps, testing MyV, PD, R2, R1, GM, WM, and MyC/WM/GM fractional volumes^{^a}

Variables	Normal-Appearing White Matter		FASI		P Value^{^b}
Variables	Median	Min-Max	Median	Min-Max	P Value^{^b}
MyCvol (mL)	0.03	0.01–0.05	0.000	0.00–0.002	.001
MyV (mL)	14.1	6.9–29.9	2.5	0–18.7	.001
MY PD	76.4	66–81.1	83.3	73.2–89	.001
MY R2	12.6	11.19–15.2	10.36	7.08–13.85	.001
MY R1	1.22	1.05–1.76	0.96	0.73–1.27	.001
WMFvol (mL)	0.13	0.05–0.17	0.02	0.00-0.13	.001
WM	64.3	26.7–100	2.7	0.00–73.5	.001
WM PD	76.4	66–80	83.3	51.1–87.8	.001
WM R2	12.6	11.19–15.22	10.36	1.99–76.1	.001
WM R1	1.21	1.05-1.76	0.96	0.73–12.31	.001
GMFvol (mL)	0.06	0.00–0.13	0.11	0.05-0.21	.001
GM	29.2	0.00–70.1	75.2	14.8–86.1	.001
GM PD	76.4	66–81.9	83.3	73.2–90.51	.001
GM R2	12.6	11.19–15.22	10.36	0.9–13.85	.001
GM R1	1.2	1.05–1.76	0.96	0.73–1.27	.001

Note:—Min indicates minimum; Max, maximum; MyC, myelin correlated fraction volume.
↵a Units are PD (PU), R1 and R2 (s-1), WM (mL), GM (mL).
↵b Wilcoxon test.