Analysis On MRI Measurement Of Low Lumbar Spinal Canal In Normal Adults

ObjectivesTo build up MRI-measured standard values of the low lumbar spinal canal diameterand area of normal adults. The clinical application of the values was evaluated through theclinical verification.MethodsLumbar spine of180normal adults (90male and90female) were scanned with MRI,which includes sagittal T1WI and T2WI and transverse T2WI. The measurement include:①median effective sagittal diameter(MESD), median sagittal diameter(MSD), spinal areaand area of dural capsule of spinal canal at the level of L3/4, L4/5and L5/S1intervertebraldisc, which were measured on transverse T2WI;②Calculate the ratios of MESD/MSD，MSD and area of dural capsule (ADC)/area of spinal canal (ASC), which were calculated.The diameters and the areas were used to observe their diagnostic value in the patients withdisc herniation. All data were analysed with statistics.Results①There is no significant difference of the the values of all diameters and ratios atthe level of L3/4, L4/5and L5/S1intervertebral disc of normal adults between the differentages and gender (P>0.05).②There were different threshold values of MESD and MSD and threshold areas ofspinal canal and dural capsule at the level of L3/4, L4/5and L5/S1intervertebral disc ofnormal adults. The values of MESD at at the level of L3/4, L4/5and L5/S1intervertebraldisc were11.64±1.46mm,11.83±1.68mm and13.25±2.03mm respectively; MSD17.68±2.40mm,17.31±2.40mm and15.63±2.36mm respectively; ADC176.03±34.03mm~2,173.24±41.49mm~2and125.99±55.83mm~2respectively; ASC226.29±42.24mm~2,229.75±54.99mm~2and267.58±70.37mm~2respectively. ③There is no significant difference of all the diameters, the areas and the ratiosbetween the levels of L3/4and L4/5intervertebral disc (P>0.05). But there was asignificant difference between level of L3/4and L5/S1intervertebral disc and the level ofL4/5and L5/S1intervertebral disc (P<0.05)④Clinical application showed that there was a significant difference between MESDand MSD in the determination of lumbar spinal stenosis and between the diameters and theareas.ConclusionThe MRI-measured diameters and areas of low lumbar spinal canal of normal adultscan offer a more precise and abundant imaging information for clinic. The clinicalapplication proves that the median effective sagittal diameter is more precise than the MSDin the degree of spinal stenosis of the1umbar disc herniation, and the ASC is moreaccuracy than diameter in the degree of spinal stenosis of the1umbardisc LateralHerniation.