Twenty-four Hours Delayed Bone Imaging In Diagnosis Of Benign Or Malignant Of The Single Spinal Lesion

Objective: The aims of this study were to evaluate the diagnosis of benign and malignant of thesingle spinal uptake lesion using semi-quantitative analysis in 24h delayed plane + computedtomography imaging by ROI technique, calculated Lesion/nomal radiocounting ratio (L/N ratio)and 24h/4h uptake ratios (TF ratio), and compared the differential diagnostic efficiency of the TFratio of radioactive concentration between planar imaging and SPECT imaging of the spine.Methods: 38 patients with malignant or benign bone disease were studied,for which the resultsof 99Tcm-MDP scintigraphy have only contained single spinal uptake lesions in the first hospitalof Shan Xi medical university between December 2009 and september 2010. Twenty female and18 male were included in this study, with an average age of 49.71±16.30 years(age range 30 to79 years). 24-hour delay plane + tomography imaging were performed after 3h 4h routine bonescan finished in all patients obtaining consent, the Capturing conditions between 4h and 24hlocal plane + tomography imaging are the same. Planar imaging counts were collected 500k,matrix 256×256, Zoom 1.0; tomography were collected 360°, 6°/frame, 25s/frame, 60frames,matrix 64×64, Zoom1.0. OSEM iterative method was applied to tomography imagesreconstruction, OSEM reconstruction iteration number was 2, a subset of the number was 10,pre-filter for the Hanning, cutoff frequency was 0.9. All patients were confirmed by finalpathology, medical imaging or follow-up clinical outcomes, pursuant to which the patients weredivided into benign and malignant groups, 11 cases of benign and malignant group of 27 patients.Application ROI techniques was used to draw the outline of 4h and 24h two planar imaging andtomography imaging site of the regional uptake in regions of interest (ROI), calculated the totalnumber radioactivecountings of 4h and 24h lesions in planar imaging (L_4h,L_4h ')and tomographyimaging (L_24h,L_24h'),then copy the ROI (ensure the same size to ROI) in adjacent normalvertebral body above or below lesion′s vertebral, calculated the total number of theradioactivecountings in parts of adjacent normal vertebral body N_4h (N_4h') and N24h (N24h'), repeatthe outlines three times and calculate the average. According to the formula TF = (L_24h/N24h)÷(L_4h/N_4h), we can calculated the TF ratio of the planar imaging and TF' ratio of the tomographyimaging. If these indicators are different, then according to the relevant quantitative indicators,we could sum up the decision point boundary value(on the boundary value point, there are themost accurate sensitivity and specificity of the differential diagnosis of benign and malignantlesions in single uptake spinal lesions) by the use of receiver operating characteristic curvetechnical (receiver operating characteristic curve,ROC curve), and obtained the best diagnostic threshold in semi-quantitative analysis of bone imaging, and calculate the correspondingdiagnostic sensitivity and specificity.Results :1. The planar imaging : The quantitative value of L/N_4h, L/N_24h, TF ratio (2.02±0.47, 2.47±0.73,1.22±0.11) in malignant lesions of was significantly higher than those in benign lesions(1.62±0.42,1.84±0.46,1.07±0.66), group differences were significant (t4h=-2.46,t24h=-3.12,p<0.05; tTF=-4.77,p <0.01); the value of L/N_24h was significantly higher than the value ofL/N_4h in malignant lesions(t=-2.25,p <0.05), while in benign lesions,there is no significantlydifferent between L/N_4h and L/N_24h(t=-1.87,p＞0.05). According comparing the area underthe ROC curve to the three quantitative indicators of L/N_4h, L/N_24h and TF values (0.752,0.838, 0.905), we can obtain that the TF value is the best quantitative indicators in thediagnosis of benign and malignant lesions in the spine single in planar imaging, when taken1.12, its sensitivity, specificity of the diagnosis of benign and malignant to spinal singlelesions were separately 100% and 77%.2. The tomography imaging: The L′/N′,L₁′/N₁′, TF ratio (4.37±1.20, 5.57±1.55, 1.28±0.09) inthe semi-quantitative analysis of malignant lesions was significantly higher than those inbenign lesions(3.35±0.62, 3.84±0.95, 1.14±0.07), group differences were significant(t4h=-2.11,t24h=-2.71,p <0.05; tTF=-3.48,p <0.01); The value of L₁′/N₁′was significantlyhigher than the value of L′/N′in malignant lesions (t=-3.37,p<0.05), while in benignlesions,there is no significantly different between L′/N′and L₁′/N₁′(t=-1.96,p＞0.05).According comparing the area under the ROC curve to the three quantitative indicators ofL/N_4h′, L/N_24h′, TF′values(0.828, 0.896, 0.946), we can obtain that the TF′value is the bestquantitative indicators in the diagnosis of benign and malignant lesions in the spine single intomography imaging, when taken 1.19, its sensitivity, specificity of the diagnosis of benignand malignant to spinal single lesions were respectively 92.6% and 90.9%.Conclusion:1. The semi-quantitative analysis of 24h delayed bone imaging have a high clinical value indifferential diagnosis of benign or malignan of the single spine lesions.2. When choosing TF'=1.19 as the quantitative differential diagnosis threshold in thesemi-quantitative analysis of delayed tomography imaging, the specificity of diagnosingbenign or malignant in single uptake spinal lesions were all significantly higher than thesemi-quantitative analysis of delayed plane imaging that TF =1.12.