ABSTRACT
Objective To analyze the changes of susceptibility in acute cerebral ischemia (ACI) using quantitative susceptibility mapping (QSM).Methods Twenty-three patients with ACI who met the criteria underwent conventional brain MR and QSM scan,and the susceptibility maps were obtained with QSM post-processing software in image processing workstation.According to DWI images,ROIs were manually drawn on lesions of ACI to obtain magnetic susceptibility on susceptibility map,including cortical gray matter (CGM),subcortical white matter (SWM),caudate (CA),globus pallidus (GP),putamen (PU),thalamus (TH),substantia nigra (SN),dentate nucleus (DN) and pons (PO).Then magnetic susceptibility of contralateral position was obtained.According to whether cerebral microbleeds (CMBs) were observed,the ACI patients were divided into CMBs group and non-CMBs group.The magnetic susceptibility of groups and different ROIs of ACI and the contralateral area were compared statistically.Results There was significant difference in magnetic susceptibility between CMBs group [(79.04 ± 52.25) × 10-9 ppd] and non-CMBs group ([-4.01 ± 44.57] × 10 9 ppd;Z=-3.297,P =0.001).The difference of magnetic susceptibility between the lesion side and the contralateral side ([-12.10±16.75]× 10-9 ppd) was statistically significant in CMBs group (Z=-3.296,P=0.001),but not in non-CMBs group (contralateral side [1.61 ±32.77] × 10-9 ppd;Z=-0.157,P=0.875).According to the location of ROIs,magnetic susceptibility had statistical differences only in PO,CGM and contralateral side (Z=-2.023,--3.130,P=0.043,0.002).Conclusion QSM can be used to quantitatively analyze magnetic susceptibility of ACI lesions and find CMBs,therefore is helpful to guiding treatment.
ABSTRACT
Objective To explore the changes of susceptibility of different sides and gender in healthy young adults with quantitative susceptibility mapping (QSM).Methods Totally 41 healthy young right-handed adults underwent conventional brain MRI and QSM scan,and the susceptibility maps were obtained by the image post-processing software.Then the ROI of the bilateral frontal grey matter (FGM),frontal white matter (FWM),caudate (CA),globus pallidus (GP),putamen (PU),thalamus (TH),substantia nigra (SN),red nucleus (RN),dentate nucleus (DN),pons (PO),corpus callosum (CC) were manually drawn to obtain magnetic susceptibility on the susceptibility map.The magnetic susceptibility of each ROI was compare between both sides,as well as gender by Mann-Whitney test.Results The magnetic susceptibility of the bilateral ROI of GP was the highest,and SN was followed,FWM was minimum.The susceptibility of bilateral FGM,FWM,CA,GP,PU,TH,SN,RN,DN,PO,CC had no statistically significant differences (all P＞0.05).The magnetic susceptibility in CA of different gender had statistically significant difference (P＜0.05).Conclusion The brain magnetic susceptibility.can be measured by QSM,and it can assess brain iron content quantitatively.
ABSTRACT
Objective To investigate the prognostic value of maximum diameter in axial plane of primary tumor (MDAPPT) on MRI in nasopharyngeal carcinoma (NPC).Methods From 2005 to 2007,333 patients with newly diagnosed and biopsy-proven NPC without distant metastasis,who underwent MRI scans of the nasopharynx and neck,were included in our study.MDAPPT was measured on MRI.The univariate analysis with the log-rank test and multivariate analysis with the Cox proportional hazards model were used to analyze the relationship between MDAPPT and prognosis.Results The median values of MDAPPT in patients with T1,T2,T3,and T4 NPC were 21.2,30.0,38.0,and 52.3 mm,respectively.For all patients with a MDAPPT of ≤30 mm,＞ 30-50 mm,and ＞ 50 mm,the 5-year overall survival (OS) rates were 81.3％,70.1％,and 51.5％,respectively (P =0.000) ; the 5-year progression-free survival (PFS) rates were 81.3％,70.0％,and 48.9％,respectively (P =0.000) ;the 5-year distant metastasisfree survival (DMFS) rates were 85.5 ％,86.5 ％,and 67.2 ％,respectively (P =0.000) ; the 5-year local relapse-free survival (LRFS) rates were 97.7％,91.5％,and 83.3％,respectively (P =0.013).The multivariate analysis showed that MDAPPT was a prognostic factor for PFS and DMFS.For the T3-T4 patients with a MDAPPT of ≤50 mm and ＞50 mm,the 5-year OS rates were 69.4％ and 52.2％ (P =0.004),the 5-year PFS rates were 68.0％ and 49.6％ (P =0.001),and the 5-year DMFS rates were 84.0％ and 66.8％ (P=0.001).In the patients with a MDAPPT ≤30 mm,the 5-year LRFS rates for those with T1,T2,T3,and T4 NPC were 10 0 ％,9 5.8 ％,9 6.3 ％,and 10 0 ％,respectively (P =0.6 4 3).Conclusions MDAPPT is a prognostic factor for PFS and DMFS in NPC,and it is an important prognostic factor in patients with T3-T4 NPC.In the NPC patients with a small MDAPPT,local control rate varies little in different T stages.
ABSTRACT
Objective To evaluate the prognostic impact of MRI-detected prevertebral space involvement in nasopharyngeal carcinoma (NPC) treated with radiotherapy and chemotherapy.Methods A retrospective analysis was performed on the clinical data of 333 patients who had newly diagnosed biopsyproven NPC without distant metastasis from 2005 to 2007.All patients underwent MRI scans of the nasopharynx and neck and were treated with two-and three-dimensional radiotherapy without or without chemotherapy.The Kaplan-Meier method was used to calculate overall survival (OS),distant metastasis-free survival (DMFS),and locoregional relapse-free survival (LRFS),and the log-rank test was used for survival difference analysis;the Cox proportional hazards regression analysis was used to assess the prognostic value of prevertebral space involvement.Results The follow-up rate was 95.2％.Prevertebral space involvement was seen in 139(41.7％) of these patients.The patients with prevertebral space involvement had significantly higher T stage and clinical stage than those without prevertebral space involvement (x2 =90.41,P =0.000;x2 =54.03,P =0.000).The 5-year OS,DMFS,and LRFS for NPC patients with and without prevertebral space involvement were 58.8％ vs.77.5％ (x2 =11.95,P =0.000),77.8％ vs.85.0％(x2=2.56,P=0.110),and 88.3％ vs.91.8％ (x2=1.51,P=0.220),respectively.After adjusting for N stage,a significant difference was still seen between the two groups with regard to 5-year OS (x2 =9.93,P =0.002).The multivariate analysis showed that prevertebral space involvement was not the independent prognostic factor for OS,DMFS,and LRFS (x2 =0.43,P =0.512 ; x2 =0.08,P =0.783 ; x2 =0.00,P =0.971).Conclusions The frequency of prevertebral space involvement is very high in NPC.The OS for the patients with prevertebral space involvement is significantly lower than those without prevertebral space involvement.But prevertebral space involvement is not the independent prognostic factor in NPC patients.