GADOLINIUM-ENHANCEMENT CHARACTERISTICS OF MAGNETIC-RESONANCE-IMAGING IN DISTINGUISHING HERNIATED INTERVERTEBRAL DISC VERSUS SCAR IN DOGS

Citation
Hs. An et al., GADOLINIUM-ENHANCEMENT CHARACTERISTICS OF MAGNETIC-RESONANCE-IMAGING IN DISTINGUISHING HERNIATED INTERVERTEBRAL DISC VERSUS SCAR IN DOGS, Spine (Philadelphia, Pa. 1976), 19(18), 1994, pp. 2089-2095
Citations number
NO
Categorie Soggetti
Orthopedics
ISSN journal
03622436
Volume
19
Issue
18
Year of publication
1994
Pages
2089 - 2095
Database
ISI
SICI code
0362-2436(1994)19:18<2089:GCOMI>2.0.ZU;2-B
Abstract
Study Design. This study is an experimental investigation on the gadol inium contrast magnetic resonance imaging (MRI) in distinguishing sequ estered disc fragment versus scar in dogs. The conspicousness of the d isc fragment and signal intensities of the disc fragment and laminecto my scar were evaluated using gadolinium-enhanced MRI and histology. Ob jectives. This study investigated the effects of timing of gadolinium injections, gadolinium doses, and aging of scar or disc on the enhance ment characteristics and conspicousness of disc fragment in MRI. Summa ry of Background Data. Contrast-enhanced MRI has been frequently used as a procedure to evaluate patients with suspected recurrent herniated discs. In contrast-enhanced MRI, the postoperative scar tissue enhanc es to a greater extent than disc fragments. Previous reports suggest d ifferent contrast enhancement characteristics of scar depending on dos es, timing of gadolinium, or maturity of scar. There are different com pounds of gadolinium agents and different doses are becoming available . There is no previous report on the evaluation of gadolinium enhancem ent characteristics in dogs with concurrent herniated disc and scar. M ethods. Six conditioned Beagle dogs underwent hemilaminectomies and di scectomies at the L3-L4 level. An autogenous disc fragment was obtaine d from the intervertebral disc of the tail. This disc fragment was pla ced anterolateral to the thecal sac, simulating a sequestered disc her niation. Three control animals underwent hemilaminectomies and discect omies alone. Each dog underwent MRI on a 1.5 Tesla scanner (3.0 mm sli ce in sagittal and axial projections with TR 500, TE 30 msec and high dose 0.3 mmol/kg of gadoteridol). Images were obtained at 15 days, 30 days, 60 days, and 90 days after surgery. At each imaging session, con trast enhancement was measured at 2 minutes, 25 minutes, and 45 minute s after gadolinium injection for kinematic analysis. Two animals at a time were killed on 30 days, 60 days, and 90 days postoperatively. Mag netic resonance imaging was done with conventional low dose 0.1 mmol/k g of gadopenetetate at 15 days and before death. Results. Results reve aled that the difference of enhancement between disc and the scar and therefore conspicuousness of disc fragment was greater on 2-23-minute images as compared with 45- minute images, and the distinction decreas ed with aging of the scar. The high dose contrast-enhanced MRI increas ed signal intensities for both disc and scar. Conspicuousness of disc fragment seemed to be better with the high-dose gadolinium compound. C onclusions. In conclusion, contrast enhancement characteristics in MRI may depend on the timing of MRI after gadolinium injection, doses of gadolinium, and aging of scar or disc.