High contrast between lumbar nerve roots and surrounding structures using dual echo 3D turbo spin echo additional fusion images.

PURPOSE: We performed lumbar spinal magnetic resonance imaging of three-dimensional (3D) dual echo volumetric isotropic turbo spin echo acquisition (DE-VISTA) and constructed DE-VISTA additional fusion images (DE-VISTA-AFI), which is the addition of DE-VISTA proton density-weighted images (DE-VISTA-PDWI) to DE-VISTA T2-weighted images (DE-VISTA-T2WI). The aim of this study was to clarify whether DE-VISTA-AFI was able to clearly delineate spinal nerve roots. METHODS: A total of 677 patients underwent lumbar MR imaging, and the signal ratio (SR) between cerebrospinal fluid and nerve roots inside the dural sac and the SR between fat and nerve roots outside the dural sac were estimated using DE-VISTA-AFI, DE-VISTA-PDWI, DE-VISTA-T2WI, and 2D-T2WI. RESULTS: The SR between cerebrospinal fluid and nerve roots inside the dural sac on DE-VISTA-AFI was higher than that on DE-VISTA-PDWI (p < 0.0001) and on 2D T2WI (p < 0.0001). The SR between the fat tissue and nerve roots outside the dural sac on DE-VISTA-AFI was higher than that on DE-VISTA-PDWI (p < 0.0001) and 2D T2WI (p < 0.0001). CONCLUSION: DE-VISTA-AFI could clearly delineate the entire length of the lumbar nerve roots that run from the cauda equina in the spinal fluid through to the fat in the lateral recess, intervertebral foramen, and outside the intervertebral foramen.

Usefulness of dual echo volumetric isotropic turbo spin echo acquisition (VISTA) in MR imaging of the temporomandibular joint.

PURPOSE: We investigated the ability to detect the articular disk and joint effusion of the temporomandibular joint (TMJ) of a method of dual echo volumetric isotropic turbo spin echo acquisition (DE-VISTA) additional fusion images (AFI). METHODS: DE-VISTA was performed in the 26 TMJ of 13 volunteers and 26 TMJ of 13 patients. Two-dimensional (2D) dual echo turbo spin echo was performed in the 26 TMJ of 13 volunteers. On a workstation, we added proton density-weighted images (PDWI) and T2 weighted images (T2WI) of the DE-VISTA per voxel to reconstruct DE-VISTA-AFI. Two radiologists reviewed these images visually and quantitatively. RESULTS: Visual evaluation of the articular disk was equivalent between DE-VISTA-AFI and 2D-PDWI. The sliding thin-slab multiplanar reformation (MPR) method of DE-VISTA-AFI could detect all articular disks. The ratio of contrast (CR) of adipose tissue by the articular disk to that of the articular disk itself was significantly higher in DE-VISTA-AFI than DE-VISTA-PDWI (P<0.05) in patients and volunteers with closed or open mouth. In volunteers, the CR between adipose tissue and the disk on DE-VISTA-AFI was marginally significant to that on 2D-PDWI at opened mouth (P=0.071) and not significantly different (P=0.18) from that at closed mouth. Joint effusion could be identified in DE-VISTA-AFI in all 8 joints that had joint effusion in DE-VISTA-T2WI but in only 3 of those joints in 2D-T2WI. The CR of joint effusion to adipose tissue on DE-VISTA-AFI did not differ significantly from that on DE-VISTA-PDWI. However, using DE-VISTA-T2WI in addition to DE-VISTA-PDWI, we could visually identify joint effusion on DE-VISTA-AFI that could not be identified on DE-VISTA-PDWI alone. CONCLUSION: DE-VISTA-AFI can depict the articular disk and a small amount of joint effusion by the required plane of MPR using the sliding thin-slab MPR method.

Visualization of coronary arterial wall based on maximum intensity fusion of whole-heart MR angiograms and water suppression SPIR 3D T(1) TFE images.

PURPOSE: We estimated the coronary artery wall using maximum intensity fusion (MIF) of whole-heart magnetic resonance (MR) angiography (WHCA) and water suppression-spectral presaturation with inversion recovery (WS-SPIR) 3D T(1)-weighted turbo field echo (3DT(1) TFE). METHODS: We created a phantom using a wall of plastic bottles varied with plastic tapes measuring 0.4 to 3.0 mm thick (0-14 sheets) by vernier caliper and compared widths with those on profile curves. In 3 patients, to clarify the capacity to visualize the coronary wall in vulnerable plaque, we acquired WS-SPIR 3D T(1) TFE and WS-spectral attenuation with inversion recovery (SPAIR) (inversion time [TI] 400 ms) 3D T(1) TFE images of carotid vulnerable plaque; also termed "lipid-rich plaque," vulnerable plaque is considered to be visualized in high intensity. We utilized the same geometric parameters and rest period on WHCA as for WS-SPIR 3D T(1) TFE. We obtained MIF of WHCA and WS-SPIR 3D T(1) TFE and measured thickness of the right coronary artery (RCA) wall on the profile curve in 18 cases. RESULTS: The widths of the dip of the lower third of the bottom to head on the profile curve were consistent with actual measurement at 1-2 mm, the usual coronary artery wall thickness. Carotid plaques of high intensity by T(1)-weighted black-blood (T(1)BB) and T(2)-weighted BB (T(2)BB) methods showed high intensity on WS-SPAIR (TI 400 ms) 3D T(1) TFE and low intensity on WS-SPIR 3D T(1) TFE. With or without vulnerable plaque in the coronary artery wall, MIF of WHCA and WS-SPIR 3D T(1) TFE reflected the coronary artery wall. We obtained bands of low intensity in MIF between epicardial fat of WS-SPIR 3D T(1) TFE and coronary artery lumen of WHCA all but mid RCA in all 18 cases. We were unable to detect mid RCA in 5 cases. The outline of the obstructed mid RCA in 1 case was clear in WS-SPIR 3D T(1) TFE. The higher velocity of RCA movement caused blurring in another 4 cases in both WHCA and WS-SPIR 3D T(1) TFE. Those wall thickness of proximal or mid RCA averaged 1.3+/-0.2 mm. CONCLUSION: Bands of low intensity between epicardial fat and coronary artery lumen on MIF of WHCA and WS-SPIR 3D T(1) TFE can reflect the coronary artery wall.