Application of echo-planar imaging correction in diffusion weighted imaging and diffusion tensor imaging of cervical spinal cord / 中华放射学杂志

Objective:To explore the value of echo-planar imaging correction (EPIC) for improving image quality of diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) of cervical cord.Methods:A total of 33 subjects (20 males, 13 females) were scanned on a 3.0 T MR scanner from January to March 2022, and the sequences included T 1WI, DWI and DTI (with and without corrections). Two observers delineated the regions of interest (ROIs) on the fused images of DWI and DTI with T 1WI before and after correction, and measured the average diffusion coefficient (ADC), fractional anisotropy (FA), and offset distance of ROIs between images with and without corrections. The subjective scores of image quality were also evaluated. The ICC or Kappa was used to test the consistency of the quantitative measurement and subjective scores by the two observers. The average values by the two observers would be used for subsequent analysis. The independent pair t-test and Wilcoxon test were used for comparison of objective measurements and Mann-Whitney U test was used for subjective image assessments between images with and without corrections. Results:The measurement data and the subjective scores of the two observers were in good agreement (ICC 0.912-0.999, Kappa 0.778-0.816). The independent sample t-test showed the subjective scores were significantly different for the DWI and DTI images between before and after geometry and/or ADC corrections. The ADC values of C6, the offset distances measured by DWI before and after correction of C4, C5, and C6 and subjective scores were significantly different ( P<0.05); The FA values of C1 and C3, ADC values of C1 and C3, offset distance of C4, C5 and C6 measured by DTI before and after correction and subjective scores were statistically significant ( P<0.001). Conclusion:EPI geometry correction and ADC value correction can significantly reduce geometric distortion, increase image quality, and thus improve the diagnosis accuracy of essential diseases.

Acid-base metabolism variants in infarct core and penumbra using amide proton transfer weighted imaging in subacute cerebral infarction / 中华放射学杂志

Objective:To assess the value of amide proton transfer weighted (APTw) imaging in the evaluation of pH changes in infarct core (IC) and ischemic penumbra (IP) in subacute cerebral infarction.Methods:The data of twenty-three subacute cerebral infarction patients with unilateral steno-occlusive disease of the middle cerebral artery (subacute infarction group) from April to November 2019 in the First Affiliated Hospital of Dalian Medical University were prospectively analyzed. Fifteen healthy volunteers were enrolled in this study as the control group. All subjects underwent conventional MRI, DWI, 3D-pseudo continuous arterial spin labeling (3D-pCASL) and APTw sequences. Based on DWI images, relative cerebral blood flow (rCBF) and APTw images to determine the region of IC, blood flow penumbra [cerebral blood flow(CBF)-DWI mismatch area, IP CBF] and metabolic penumbra (APTw-DWI mismatched area, IP APT). 3D ROIs were used to semi-automatically measure the APTw signals and the volume of IC and IP CBF of the patients in subacute infarction group. The comparison of APTw signals between the infarct side and the contralateral side in the subacute infarction group, the comparison of bilateral APTw signals in the control group, and the comparison of APTw signals in the IC and IP CBF regions were performed by paired-sample t test or Wilcoxon signed-rank test. The paired-sample t test or Mann-Whitney U test was used to compare the APTw signals between the two groups. The Friedman test was applied to compare the difference of volumes among IP CBF1.5, IP CBF2.5 and IP APT . Results:There was no significant difference of the APTw signals among the IC, the contralateral side in the subacute infarction group and the control group ( P>0.05). The APTw signals of IP CBF and IC of the infarction group were statistically different ( P<0.05). Compared with the contralateral side of IP CBF1.5 (3.7±1.7, -1.84±1.48, 5.57±2.75), the APTwmax (3.07±1.41, t=-3.012, P=0.006), APTw min [-1.30 (-1.74, -0.57), Z=-2.099, P=0.036], and APTwmax-min(4.51±2.58, t=-3.273, P=0.003) signals in the IP CBF1.5 were decreased ( P<0.05). Compared with the contralateral side of IP CBF2.5 [-1.53 (-2.80, -0.91), 5.31±2.61], the APTw min [-1.08 (-1.60, -0.49), Z=-2.616, P=0.009] and APTwmax-min (4.41±2.72, t=-3.228, P=0.004) signals in the IP CBF2.5 were decreased. The volumes of IP CBF1.5 [107.51(50.08, 138.61)mm 3], IP APT [99.00 (53.27, 121.335) mm 3] and IP CBF2.5 [89.91 (51.53, 139.87) mm 3] were successively reduced (χ2=7.913, P=0.019), and the volume of IP CBF2.5 was significantly smaller than that of IP CBF1.5 ( P=0.037). Conclusion:The acid-base metabolism in the IC of subacute cerebral infarction is not obvious, but the blood flow penumbra has local acid-base metabolism imbalance, and the range of metabolic penumbra coincides with the blood flow penumbra.

Optimization of scanning protocol in low-dose one-stop CT perfusion imaging combined with CTA of whole brain / 中国医学影像技术

Objective To optimize protocol in one-stop whole brain CT perfusion imaging (CTP) combined with CTA.Methods Totally 45 subjects underwent one-stop whole brain CTP combined with CTA with three different scanning protocols and 22 phases.CTA images were reconstructed from CTP original data at the tenth phase,the protocols of three scanning groups were as follows:Group A using automatic tube current modulation technique (ATCM) with low noise index (NI;NI=2),group B with fixed tube current (325 mA) and group C using ATCM with slightly low NI (NI=2.5),and the other phases of three groups were performed with ATCM and NI=8.Tube voltage of all three scanning protocols was 100 kV.The radiation dose and related parameters were recorded.Objective parameters including image noise (SD),SNR,CNR and perfusion parameters in different parts of the brain parenchyma and subjective scores of CTA,CTP image quality were compared among three groups.Results There was significant difference of effective dose (ED) among three groups (P＜0.05).ED of group A was higher than that of group B and C (P=0.043,0.001).No difference was found in CTA image noise,SNR,CNR nor subjective scores among three groups (P=0.218,0.545,0.575,0.900),neither of CTP images among three groups (P＞ 0.05).Conclusion Using ATCM and increasing NI appropriately may reduce radiation dose in one-stop CTP combined with CTA.

Differential diagnosis between Rathke cleft cyst and cystic pituitary adenoma using MRI / 实用放射学杂志

Objective To make correct diagnosis for Rathke cleft cyst(RCC)and cystic pituitary adenomas(CPA)through retrospective analysis of characteristics of MRI.Methods RCC (n=30)and CPA (n=30)confirmed by surgery and pathology were analyzed retrospectively.Following characteristics of lesions were observed:morphology,size,location,range,T1WI signal intensity and patterns of enhancement,presence of intracystic fluid level,septum,nodule,hypointense rim on T2WI and change of the pituitary stalk.The independent sample t-test and χ2 test were used respectively to analyze differences between two groups of continuous variables and categorical variables.Results Most of RCC were oval,less than 2 cm3,under the optic chiasm and within the bilateral cavernous sinus,various for signal intensity,without or with thin-walled contrast enhancement.Intracystic nodule accounted for 40% of cases and there were double cystic nodules in 1 case.Obvious contrast enhancement of intracystic nodule was found in 1 case.Pituitary stalk was in center.Most of CPA were snowman shaped,bigger than 2 cm3,off middle line location,with compression of the optic chiasm and sellar base,had thick-walled contrast enhancement,with intracystic fluid level and septum,had hypointense rim on T2WI.The pituitary stalk was shifted.Conclusion The MRI findings of RCC and CPA are significant differences in the shape,size,intracapsular structure,enhanced performance and changes of surrounding structure.

CT imaging and pathological features of maxillofacial malignant myoepithelioma / 实用放射学杂志

Objective To evaluate CT imaging and pathological features of maxillofacial malignant myoepithelioma (MME). Methods A total of eight patients with pathologically confirmed MME of the maxillofacial region were underwent non-enhanced and contrast-enhanced CT scans.CT features of the lesions were assessed as follows:location,number,shape,size,enhancement pattern and CT number on non-enhanced and contrast-enhanced scan.CT features were compared with the pathological results.Results All the lesions were unilateral,in which mixed type with clear cells and spindle cells in 5 cases,mixed type with epithelioid cells and plas-ma cells in 2 cases,and clear cell type in one case.8 cases were manifested as lobulated mass.On non-enhanced scan,the density of all the lesions were hetergeneous with cystic area,1 case with calcification and 2 cases with bone destruction.On the contrast-en-hanced CT,all the lesions were showed hetergeneously moderate or obvious enhancement,and cystic,line and crack areas without the enhancement were observed.Minor vessel and spiculate protuberance of marginal zone on the arterial phase were observed in most le-sions.Conclusion MME has different pathological subtypes and characteristic CT features.CT is an effective method to diagnose MME.

The morphologic and hemodynamic abnormalities study of jugular vein in volunteers / 实用放射学杂志

Objective To investigate jugular vein morphological changes with three dimension phase contrast magnetic resonance venography(3D PC MRV),and to explore hemodynamic features using MR phase contrast cine (MR PC cine).Methods Sixty-five healthy volunteers performed 3D PC MRV and MR PC-cine sannings.MRV ranged from torcular herophili to brachiocephalic veins, and the raw data of PC-cine was acquired at cervical 2-3(C2-C3)level perpendicular to the Jugular veins(JVs)with the maximum encoding velocity of 50 cm/sec.Jugular vein showing absent or tip shape(cross-sectional area less than 12.5 mm2 )was considered abnormal,and flat,crescent,oval,round shapes were considered normal.Data of PC-cine was processed by computer to evaluate the hemodynamic features.Results Nine (13.85%)of 65 cases were abnormal that unilateral jugular vein showing needle-pointed narrow or absent,and 8 cases on the left,and one case on the right;Weak correlation was found between jugular veins pattern and the age.The right sided values in volunteers were higher than that of the left side.Conclusion The morphology and hemodynamics of jugular veins in volunteers showed significant difference between sides,and weak correlation is found between the morphology and aging.

Deep cerebral venous morphology and oxygenation content in patients with multiple sclerosis using susceptibility weighted imaging / 中华放射学杂志

Objective To evaluate the deep brain venous blood oxygen content changes in patients with multiple sclerosis(MS) using susceptibility weighted imaging (SWI), and to explore the ability of SWI in reflecting the clinical condition. Methods Forty-four MS patients were prospectively enrolled in the study. All the clinical-proved patients meeting the McDonald standards (2005 revised) underwent conventional MRI, SWI, and 12 cases of them underwent MRI review from 12 to 16 months interval. all the patients' clinical condition were quantified according to the expanded disability status scale(EDSS). The score was 0.5—6.5. Sixty-five age- and gender- matched healthy volunteers underwent conventional MRI and SWI. The blood oxygen content of the deep brain venous were estimated by the veins phase value, and differential phase values of blood vessels and surrounding tissues (Δφ) were processed with SPIN software. The blood vessels consist of bilateral BV, SMCV, ICV, STV and FMV, PMV, OMV. The difference of Δφvalue in different veins between MS patients and the controls was compared using independent sample t-test, and the Δφ value comparison of MS patients in different time were performed by using paired t test; The correlation ofΔφvalue between MS and EDSS was analyzed using Spearman correlation. Results TheΔφvalue of BV, SMCV, ICV, STV were 856.6 ± 246.4, 600.6 ± 155.2, 965.9 ± 205.4, 844.2 ± 149.7 in MS, and 767.6±145.1, 536.2±123.5, 892.8±156.3, 783.1±148.5 in controls, respectively. TheΔφvalue was higher in MS patients than the controls (t=2.157, 2.303, 2.005, 2.103,P<0.05). The twelve patients'Δφvalues of BV, ICV,STV were 729.4±275.1, 906.1±219.2, 737.2±159.1 in the first time, and 923.2±211.6, 1017.3±211.1, 919.3 ± 165.9 in the second time, and all the values increased in the review of the interval of 12 to 16 months (t=-3.092,-6.420,-3.972,P<0.05). The phase value of PMV and OMV had significant positive correlation with EDSS scores(r=0.638, 0.642,P<0.01). Conclusions The state of hypoxia of the brain parenchyma appears in MS patients, and hypoxia may become worse with the extension of course. The extent of hypoxia can reflect the disability of the patients.

Values of kinetic features measured by computer-aided diagnosis for breast MRI / 中华放射学杂志

Objective To investigate the value of kinetic features measured by computer-aided diagnosis (CAD)for breast MRI.Methods One hundred and sixty four lesions diagnosed pathologically by operation or biopsy comprised the analysis set.Automated lesion kinetic information from CADStream programs for breast MRI was identified.Three CAD variables were compared for benign and malignant lesions: initial phase peak enhancement (greatest percentage of signal intensity increase on first contrast enhanced sequence),delayed phase enhancement categorized by a single type of kinetics comprising the largest percentage of enhancement (washout,plateau,or persistent),and delayed phase enhancement categorized by single most suspicious type of kinetics (any washout ＞ any plateau ＞ any persistent).Morphological characteristics of breast lesions were described according to breast imaging and reporting data system (BI-RADS).Initial phase peak enhancement mean values between benign and malignant breast lesions were compared by using Wilcoxon rank-sum test,delayed phase enhancement categorized by a single type of kinetics comprising the largest percentage of enhancement or by single most suspicious type of kinetics between benign and malignant breast lesions were compared by using Chi-square test.Results There were 72 benign and 92 malignant breast lesions.A total of 123 (75.0％) mass lesions were identified,and the other 41 (25.0％) lesions showed no mass.Thirty lesions were BI-RADS-MRI 2,68 lesions were BI-RADS-MRI 3,43 lesions were BI-RADS-MRI 4,23 lesions were BI-RADS-MRI 5.Initial phase peak enhancement mean values of benign and malignant lesions were 237％ (69％ to 629％)and 336％ (86％ to 793％),respectively.There was no significant difference between benign and malignant lesions in initial peak enhancement mean value (Z =-1.626,P =0.104).Delayed phase enhancement categorized by single most suspicious type of kinetics (any washout ＞ any plateau ＞ any persistent) for benign and malignant lesions were 15,10,47 and 2,3,87 respectively.There was a significant difference between benign and malignant lesions (x2 =23.562,P =0.000).Initial peak enhancement value ＜ 100％ or ≥100％ were 5 and 67 for benign lesions,3 and 89 for malignant lesions,respectively.There was no significant difference between benign and malignant lesions at 100％ threshold (x2 =1.181,P =0.277).Delayed phase enhancement categorized by a single type of kinetics comprising the largest percentage of enhancement (washout,plateau,or persistent) for benign and malignant lesions were 48,6,18 and 47,15,30 respectively.There was no significant difference between benign and malignant lesions (x2 =4.496,P =0.106).Conclusions Of CAD kinetics analyzed,only delayed enhancement categorized by most suspicious type is helpful for the differentiation between benign and malignant lesions.However,there is significant overlap between initial peak enhancement at 100％ threshold or delayed kinetics categorized by largest percentage enhancement types of benign and malignant lesions,so lesion morphologic features should be considered.

Functional MRI research of smoker's responses to smoking olfactory cue / 中国医学影像技术

Objective To detect different activated patterns of heavy smokers in different states as well as between smokers and non-smokers. Methods Seventeen subjects including 12 heavy smokers and 5 non-smokers (controls) were examined with functional magnetic resonance imaging (fMRI) performing smoking-related olfactory cue tasks. The data were processed with SPM2. These different patterns were compared between the two groups. Results When smokers were exposed to the smoking olfactory cue in the abstinent state, activation was found on the left superior frontal gyrus (BA8, 9, 10, 11), left middle frontal gyrus (BA8, 10, 11, 46), left inferior frontal gyrus (BA9), left medial frontal gyrus (BA6, 8, 10,11), right superior frontal gyrus (BA10), right middle frontal gyrus (BA8, 9), right inferior frontal gyrus (BA45, 47), right medial frontal gyrus (BA9, 11), left callosal gyrus (BA24, 31), right callosal gyrus (BA24, 37), right middle temporal gyrus (BA21) and both sides of the thalamus and cerebellum. When smokers were exposed to the smoking olfactory cue in the satiated state, activation could be found on both sides of the prefrontal lobe and cerebellar hemisphere, while there was no activation on the other brain regions. No activation was found on the whole brain of the nonsmokers,except for a little small volume active points appeared in individual subjects, possibly caused by the picture noise. Conclusion The Limbic system (cingulate cortex, thalamus) and the prefrontal lobe play an important role in the cue-induced smoking craving approved from the new perspective of the olfactory. It is feasible to research smoking addicts' brain activation and the role of neural mechanisms using olfactory stimulation with clinical 1.5T MRI equipment.