Intraoperative 3T MR Imaging for Spinal Cord Tumor Resection: Feasibility, Timing, and Image Quality Using a “Twin” MR–Operating Room Suite

T.P. Duprez; A. Jankovski; C. Grandin; L. Hermoye; G. Cosnard; C. Raftopoulos

doi:10.3174/ajnr.A1134

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Fig 1.
Case 1. A, Preoperative midsagittal FSE T2-weighted image at 1.5T (TR, 4000 ms; TE, 75.8 ms; echo train length (ETL) 20; 2 NEX; acquisition time (AT), 3′36“ for 11 4-mm-thick sections): swelling and abnormal hyperintensity of the diseased segment of the cord were obvious. B, Intraoperative midsagittal FSE T2-weighted image at 3T after closure of the surgical wound. The 2 elements had been put on the midline of the patient's back in the cranial-caudal direction without capability of SENSE acquisition because of insufficient overlapping between coils. Inflatable balloon of the laryngeal tube was visible (arrow). IQ was rated excellent by using following PSPs: TR, 2209 ms; TE, 120 ms; ETL 20, 4 NEX; no SENSE acceleration factor; AT: 4′56” for 11 4-mm-thick sections.
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Fig 2.
Case 2. Preoperative images. Midsagittal contrast-enhanced FSE T1- (A) and T2-weighted (B) views showed the usual features of spinal cord ependymoma at the T1-T2 level exhibiting pathognomonic hemosiderin-containing epidural “caps” (ball arrowheads in B). PSPs for T1-weighted sequence were as follows: TR, 530 ms; TE, 7.8 ms; ETL, 4; 4 NEX; SENSE acceleration factor, 1.4; AT, 4′04“ for 11 4-mm-thick sections. PSPs for T2-weighted sequence were as follows: TR, 2209 ms; TE, 120 ms; ETL, 20 ms; 4 NEX; SENSE acceleration factor, 1.4; AT: 3′28” for 11 4-mm-thick sections. On the T2-weighted image (B), SNR for cord and CSF were 119 and 301, respectively. Cord/CSF CNR was 182. C, Intraoperative midsagittal contrast-enhanced FSE T1-weighted view (similar section location and PSP as A) showed trapped air bubble at upper pole of resection site (arrow) and unmodified appearance of inferior hemosiderin-containing epidural cap (ball arrowhead). D, Intraoperative midsagittal FSE T2-weighted view (similar section location and PSP as B) again showed air bubble mimicking epidural (arrow) and unchanged true inferior epidural cap (ball arrowhead). SNRs for cord and CSF were 58 and 194, respectively. Cord/CSF CNR was 135.
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Fig 3.
Case 3. Preoperative images. Midsagittal postcontrast FSE T1- (A) and T2-weighted (B) views showing usual features of a spinal cord glioma. C–E. Intraoperative images. Midsagittal precontrast FSE T1-weighted (C), postcontrast FSE T1-weighted (D), and FSE T2-weighted views: observe similar phenomenon of air bubble trapping within surgical field (arrow in C) as in case 2 and contrast-enhancement of the margins of the resection cavity (thin arrows in D) at this early postcontrast phase of the intraoperative MR procedure. Observe true intraoperative conditions with a Gelfoam roll plugged on open dura (ball arrowhead in C). Similar PSPs as for the previous patient were used. F–H, Intraoperative images. Serial transverse FSE T1-weighted sections at the level of C7, before contrast agent perfusion (F), at 8 minutes (G), and at 30 minutes (H) after perfusion: striking increase in thickness of enhanced margins of the resection cavity were obvious comparing F to G and H. PSPs were as follows: TR, 530 ms; TE, 7.8 ms; ETL, 4; 4 NEX; SENSE acceleration factor, 1.6; AT, 3′15“ for 16 4-mm-thick sections.