An Imaging Anatomy And Technology Study Of The Thoracic Dorsal Root Ganglion And Its Branch

Objective: To provide reliable imaging anatomy of DRG and its branchfor improving the curative effect of micro-invasive interventional therapy inthoracic neuropathic pain, and evaluate a variety of imaging techniques indisplaying of normal thoracic DRG and its branch evaluation value.Materials and methods: Volunteers observation：Imaging of thoracicDRG and its branch of120healthy volunteers by employing FRFSE、fs-FRFSE、STIR and3D FIESTA-c sequences. These original images werereconstructed by MPVR, CPR and other post-processing technologyreconstruction, focus observation contrast, edge sharpness and other imageinformation of thoracic DRG, the preganglionic nerve tissue(Nerve rootbefore ganglion in the dural sac) and postganglionic nerve tissue(the nerveafter ganglion outside the spinal canal) by combination of axial, coronal andsagittal plane. Two senior Radiologists graded the imaging findings into three,Grade1: with sharp and smooth edges; Grade2: irregular and blurred edges;Grade3: insignificant findings, and compared the accuracy of the fourimaging modalities in identifying them. Autopsy observation：18anticorrosive normal human cadaveric thoracic spine specimens wereimagined by CTM and MRI3D FIESTA-c. The original CT images werereconstructed through CPR whereas MRI images were reconstructed bypost-processing technologies as mentioned earlier in clinical observationsection. The findings obtained by these two modalities were evaluated to seewhich grade (grading proposed by the senior Radiologist) do they fit. Comparing these images with cadaveric specimen’s anatomy and digitizedimage, best technology for imaging thoracic DRG and its branches anatomywere determined.Results: Volunteers observation: Number of volunteers displayinggrade1imaging findings on FRFSE sequence for T1-12preganglionic nervetissue was respectively:105,94,58,72,55,58,62,91,104,128,144,156; that forfs-FRFSE sequences was:66,50,20,19,19,27,28,36,74,80,96,92; for STIRsequence:31,16,31,3,5,5,15,23,24,25,48,57; and for FIESTA-c was:240,240,240,240,234,240,240,236,240,240,240,240. Number of volunteersdisplaying grade1imaging findings on FRFSE sequence for T1-12DRG wasrespectively:160,140,133,114,78,73,120,134,163,151,205,188; that for fs-FRFSE sequences was:62,54,33,18,22,27,40,54,97,105,101,97；for STIRsequence:58,64,60,12,7,27,16,23,31,43,57,73；and for FIESTA-c was:240,240,240,240,236,240,240,235,240,240,240,240. Number of volunteersdisplaying grade1imaging findings on FRFSE sequence for T1-12postganglionic nerve tissue was respectively:106,128,72,92,51,63,76,81,107,117,169,180;that for fs-FRFSE sequences was:49,39,12,15,8,9,22,27,59,54,68,85;for STIR sequence:41,11,6,0,0,6,8,8,9,13,43,31; and for FIESTA-cwas:240,240,240,240,232,240,240,234,240,240,240,240. Each sequencesaccuracy in imaging anatomy of thoracic DRG and its branches using KruskalWallis H-method, showed statistically significant difference (P<0.05). Wefound that26DRGs（0.9%,26/2880）have variation in volunteers. Autopsyobservation: Number of autopsy displaying grade1imaging findings onCTM for T1-12preganglionic nerve tissue was respectively:36,35,33,31,32,32,36,33,35,34,36,33; and for FIESTA-c was:36,35,31,30,31,31,34,30,33,34,33,36. Nu mber of autopsy DRG displaying grade1imaging findings on CTM for T1-12preganglionic nerve tissue was respectively:36,36,33,32,33,34,34,35,35,36,35,36; and for FIESTA-c was:36,36,33,31,31,32,32,32,33,35,35,36. Number of autopsy DRG displaying grade1imaging findings on CTM for T1-12postganglionic nerve tissue wasrespectively:36,33,30,27,25,25,29,25,28,32,33,36; FIESTA-c was:36,36,33,31,33,30,33,33,33,34,36,36. Evaluating CTM and MRI FIESTA-c accuracy inimaging anatomy of thoracic DRG and its branches using Kruskal WallisH-method, didn’t show statistically significant difference (P>0.05). DRGimaging of autopsy showed variation in7DRG（1.6%,7/432）all of whomwere found to have pathological manifestation.Conclusions: MRI can be used in the imaging of thoracic DRG and itsbranches. The display effect of FIESTA-c sequence was found superior toFRFSE, fs-FRFSE, and STIR sequence. FIESTA-c sequence can be used foraccurate imaging evaluation. There was no statistically significant differencebetween CTM and FIESTA-c in displaying thoracic DRG and itsbranches.CTM as FIESTA-c sequence can also give accurate imagingevaluation（P>0.05）. Anatomical variations in thoracic DRG and its brancheswere observed during the study.