Optimal Parameters for Virtual Mono-Energetic Imaging of Liver Solid Lesions / 中国医学科学院学报

Objective To explore the optimal parameters for virtual mono-energetic imaging of liver solid lesions. Methods A retrospective analysis was performed on 60 patients undergoing contrast-enhanced spectral CT of the abdomen.The iodine concentration values of hepatic arterial phase images and the CT values of different mono-energetic images were measured.The correlation coefficient and coefficient of variation were calculated. Results The average correlation coefficients between iodine concentrations and CT values of hepatic solid lesion images at 40,45,50,55,60,65,and 70 keV were 0.996,0.995,0.993,0.989,0.978,0.970,and 0.961,respectively.The correlation coefficients at 40(P=0.007),45(P=0.022),50 keV (P=0.035)were higher than that at 55 keV,and the correlation coefficients at 40 keV(P=0.134) and 45 keV(P=0.368) had no significant differences from that at 50 keV.The coefficients of variation of the CT values at 40,45,and 50 keV were 0.146,0.154,and 0.163,respectively. Conclusion The energy of 40 keV is optimal for virtual mono-energetic imaging of liver solid lesions in the late arterial phase,which is helpful for the diagnosis of liver diseases.

Two Cases of Hypovascular Pituitary Metastases and Literature Review / 中国医学科学院学报

Pituitary metastasis,a rare kind of intracranial malignant tumor,is characterized by metastasis from all parts of the body to the pituitary.The common tumors metastatic to pituitary are abundant with blood supply,located in the posterior pituitary lobe and/or the pituitary stalk.The lesion shows infiltrative growth,and mainly demonstrates low signal on T1 weighted imaging and high signal on T2 weighted imaging.It is usually enhanced significantly after iodinated contrast administration.The metastatic tumor with poor blood supply is similar to pituitary macroadenoma on magnetic resonance image,which makes it difficult to be differentiated.We reported two cases of pathologically diagnosed pituitary metastasis with poor blood supply and reviewed related papers,aiming to provide the imaging differentiation points of hypovascular pituitary metastasis.

Evaluation of Lateral Pterygoid Muscle Contraction in Patients with Temporomandibular Disorders Based on 3D-T2 Weighted Imaging / 中国医学科学院学报

Objective To evaluate lateral pterygoid muscle(LPM)contraction in the patients with temporomandibular disorders(TMD)based on 3D-T2 weighted imaging(3D-T2WI).Multiplanar reconstruction(MPR)was employed to measure the length of LPM in the images taken in closed-and open-mouth positions. Methods Seventeen TMD patients [age of(29.82±10.70)years,males/females=8/9] and 13 normal volunteers [control,age of(23.54±3.31)years,males/females=6/7] received 3D-T2WI of the temporomandibular joints in closed-and open-mouth positions from November 2019 to April 2020 in Department of Radiology,Hainan Hospital of Chinese PLA General Hospital.According to the position of the discs,the subjects were classified into the following groups:TMD with disc displacement without reduction(TMD-DDwoR),TMD with disc displacement with reduction(TMD-DDwR),TMD without disc displacement(TMDwoDD),and normal control without disc displacement(NCwoDD).MPR was employed to measure the maximal length of the superior belly of LPM.One-way analysis of variance,receiver operating characteristic curve,and permutation test were employed for the statistical analyses. Results The contraction of LPM was significantly shorter in TMD-DDwoR group [(3.36±1.96)mm] than in TMDwoDD group [(7.90±3.95)mm],NCwoDD group [(8.77±3.13)mm](

CT and Magnetic Resonance Imaging Findings of the Intracranial Extra-cerebral Chondroma:A Case Report / 中国医学科学院学报

Intracranial intradural chondroma is a rare disorder,the imaging findings of which have been rarely reported.The current study reported a case of intracranial extra-cerebral chondroma and described the detailed CT and magnetic resonance imaging findings,which would provide valuable imaging evidence for the diagnosis of intracranial extra-cerebral chondroma.

Reproducibility Analysis of Iodine Concentrations of Abdominal Parenchymal Organs Based on Spectral CT / 中国医学科学院学报

Objective To investigate the intra-and inter-observer reproducibility of iodine concentrations of abdominal parenchymal organs based on spectral CT.Methods The water-free iodine images of the venous phase were retrospectively obtained from 50 patients with abdominal dynamic spectral CT scans.The iodine concentrations were measured in the left,right and caudate lobes of liver,spleen,pancreas and bilateral kidneys.Intraclass correlation coefficient(ICC)and Bland-Altman plot were employed to analyze the intra-and inter-observer reproducibility.Results The intra-observer ICCs of the left,right and caudate lobes of liver,spleen,pancreas,and left and right kidneys were 0.938(0.894,0.965),0.932(0.884,0.961),0.939(0.895,0.965),0.947(0.909,0.970),0.912(0.851,0.949),0.946(0.906,0.969)and 0.907(0.842,0.946),which indicated good intra-observer reproducibility.The inter-observer ICCs of the left,right and caudate lobes of liver,spleen,pancreas,and left and right kidneys were 0.947(0.909,0.970),0.927(0.875,0.958),0.943(0.902,0.968),0.956(0.924,0.975),0.934(0.887,0.962),0.927(0.875,0.958)and 0.892(0.818,0.937),which indicated good inter-observer reproducibility.Bland-Altman plots presented that more than 95% points of the intra-observer differences located within 95% CI of limits of agreement for the caudate lobe of liver,spleen,pancreas and bilateral kidneys,which was same as inter-observer differences of the caudate lobe of liver,spleen and right kidney.Conclusion The iodine concentration measurement based on the spectral CT presented good intra-and inter-observer reproducibility for the caudate lobe of liver and spleen.

Papillary Tumor of the Pineal Region:Report of One Case / 中国医学科学院学报

We report a case of papillary tumor in the pineal region.The imaging findings mainly included:(1)slight high density on CT images;(2)short T1 signal,cystic changes,and evident enhancement on magnetic resonance imaging.

Optimal Mono-energy in Mono-energetic Spectral Computed Tomography of Enhanced Renal Cortex in Cortical Phase Based on Iodine Concentration / 中国医学科学院学报

Objective To identify the optimal mono-energetic enhanced spectral CT for renal cortex in cortical phase based on the iodine concentration. Methods Fifty patients with normal renal function received the abdominal enhanced spectral CT examination.The iodine concentration and CT values of the multiple mono-energetic spectral images were measured on renal cortex in cortical phase,and the correlation between the iodine concentration and the CT values and the coefficient of variation(CV)were analyzed. Results The correlation analysis demonstrated that the correlation coefficient was 0.994,0.994,0.993,0.987,0.976,0.960,and 0.938 between mono-energetic spectral CT images(40-100 keV with interval 10 keV,respectively)and iodine concentration(all

Effect of MR Field Strength on the Texture Features of Cerebral T2-FLAIR Images: A Pilot Study / 中国医学科学杂志(英文版)

Objective To investigate effect of MR field strength on texture features of cerebral T2 fluid attenuated inversion recovery (T2-FLAIR) images. Methods We acquired cerebral 3D T2-FLAIR images of thirty patients who were diagnosed with ischemic white matter lesion (WML) with MR-1.5T and MR-3.0T scanners. Histogram texture features which included mean signal intensity (Mean), Skewness and Kurtosis, and gray level co-occurrence matrix (GLCM) texture features which included angular second moment (ASM), Contrast, Correlation, Inverse difference moment (IDM) and Entropy, of regions of interest located in the area of WML and normal white matter (NWM) were measured by ImageJ software. The texture parameters acquired with MR-1.5T scanning were compared with MR-3.0T scanning. Results The Mean of both WML and NWM obtained with MR-1.5T scanning was significantly lower than that acquired with MR-3.0T (0.05). ASM, Correlation and IDM of both WML and NWM acquired with MR-1.5T revealed significantly lower values than those with MR-3.0T (<0.001), while Contrast and Entropy acquired with MR-1.5T showed significantly higher values than those with MR-3.0T (<0.001). Conclusion MR field strength showed no significant effect on histogram textures, while had significant effect on GLCM texture features of cerebral T2-FLAIR images, which indicated that it should be cautious to explain the texture results acquired based on the different MR field strength.

Hypovascular Pituitary Metastasis from Poorly Differentiated Lung Adenocarcinoma:Report of One Case / 中国医学科学院学报

Pituitary metastasis is a rare intracranial malignant tumor originated from other malignant tumors at other parts of the body.Pituitary metastases are typically hypervascular,while hypovascular pituitary metastasis is rare.Radiologically,hypovascular pituitary metastasis is difficult to be distinguished from pituitary adenoma.This article reports one case of pathologically confirmed hypovascular pituitary metastasis,with the main diagnostic clues including history of malignant tumor,presence of normal pituitary in the intrasellar region,and isointensity on T1 and T2 sequence.

Fibrous Meningioma with Ring Enhancement in Cerebellopontine Angle Region:Report of One Case / 中国医学科学院学报

Fibrous meningioma is a common subtype of meningioma. Contrast-enhanced scan typically shows evident homogeneous enhancement,while ring enhancement has not been described. In this article,we report a case of fibrous meningioma with ring enhancement in cerebellopontine angle region.

Ependymoma in Sellar Region:Report of One Case / 中国医学科学院学报

Ependymoma arises from the ependymal cells of the ventricles and the ependymal cell nest in the white matter of the extra-ventricles. It may be located inside or outside ventricle and can be anatomically classified into supra- and infratentorial ependymomas. Supratentorial ependymoma can be found both inside and outside ventricle but is rarely seen in the sellar regio. This article reports a pathologically confirmed ependymoma case featured by plastic growth,nodular calcification,and flow-void signal.

Atypical Cavernous Hemangioma of the Trigeminal Nerve:Report of One Case / 中国医学科学院学报

Extracerebral cavernous hemangioma typically occurs in cavernous sinus in middle cranial fossa,showing iso-or hypointensity on T1WI,obvious hyperintensity on T2WI,and evident enhancement after contrast administration during magnetic resonance imaging(MRI).In this article we report one case of atypical cavernous hemangioma of the trigeminal nerve,with atypical MRI findings including isotense or slight long T2 signal,dotty short T1 signal,and non-enhancement on T1WI.

Value of Texture Analysis of Intravoxel Incoherent Motion Parameters in Differential Diagnosis of Pancreatic Neuroendocrine Tumor and Pancreatic Adenocarcinoma / 中国医学科学杂志(英文版)

Objective To evaluate the value of texture features derived from intravoxel incoherent motion (IVIM) parameters for differentiating pancreatic neuroendocrine tumor (pNET) from pancreatic adenocarcinoma (PAC).Methods Eighteen patients with pNET and 32 patients with PAC were retrospectively enrolled in this study. All patients underwent diffusion-weighted imaging with 10 b values used (from 0 to 800 s/mm ). Based on IVIM model, perfusion-related parameters including perfusion fraction (f), fast component of diffusion (D) and true diffusion parameter slow component of diffusion (D) were calculated on a voxel-by-voxel basis and reorganized into gray-encoded parametric maps. The mean value of each IVIM parameter and texture features [Angular Second Moment (ASM), Inverse Difference Moment (IDM), Correlation, Contrast and Entropy] values of IVIM parameters were measured. Independent sample t-test or Mann-Whitney U test were performed for the between-group comparison of quantitative data. Regression model was established by using binary logistic regression analysis, and receiver operating characteristic (ROC) curve was plotted to evaluate the diagnostic efficiency.Results The mean f value of the pNET group were significantly higher than that of the PAC group (27.0% vs. 19.0%, P = 0.001), while the mean values of D and D showed no significant differences between the two groups. All texture features (ASM, IDM, Correlation, Contrast and Entropy) of each IVIM parameter showed significant differences between the pNET and PAC groups (P=0.000-0.043). Binary logistic regression analysis showed that texture ASM of D and texture Correlation of D were considered as the specific imaging variables for the differential diagnosis of pNET and PAC. ROC analysis revealed that multiple texture features presented better diagnostic performance than IVIM parameters (AUC 0.849-0.899 vs. 0.526-0.776), and texture ASM of D combined with Correlation of D in the model of logistic regression had largest area under ROC curve for distinguishing pNET from PAC (AUC 0.934, cutoff 0.378, sensitivity 0.889, specificity 0.854).Conclusions Texture analysis of IVIM parameters could be an effective and noninvasive tool to differentiate pNET from PAC.

Differential Diagnostic Value of Texture Feature Analysis of Magnetic Resonance T2 Weighted Imaging between Glioblastoma and Primary Central Neural System Lymphoma / 中国医学科学杂志(英文版)

Objective To investigate the difference in tumor conventional imaging findings and texture features on T2 weighted images between glioblastoma and primary central neural system (CNS) lymphoma.Methods The pre-operative MRI data of 81 patients with glioblastoma and 28 patients with primary CNS lymphoma admitted to the Chinese PLA General Hospital and Hainan Hospital of Chinese PLA General Hospital were retrospectively collected. All patients underwent plain MR imaging and enhanced T1 weighted imaging to visualize imaging features of lesions. Texture analysis of T2 weighted imaging (T2WI) was performed by use of GLCM texture plugin of ImageJ software, and the texture parameters including Angular Second Moment (ASM), Contrast, Correlation, Inverse Difference Moment (IDM), and Entropy were measured. Independent sample t-test and Mann-Whitney U test were performed for the between-group comparisons, regression model was established by Binary Logistic regression analysis, and receiver operating characteristic (ROC) curve was plotted to compare the diagnostic efficacy.Results The conventional imaging features including cystic and necrosis changes (P=0.000), 'Rosette' changes (P=0.000) and 'incision sign' (P=0.000), except 'flame-like edema' (P=0.635), presented significantly statistical difference between glioblastoma and primary CNS lymphoma. The texture features, ASM, Contrast, Correlation, IDM and Entropy, showed significant differences between glioblastoma and primary CNS lympoma (P=0.006, 0.000, 0.002, 0.000, and 0.015 respectively). The area under the ROC curve was 0.671, 0.752, 0.695, 0.720 and 0.646 respectively, and the area under the ROC curve was 0.917 for the combined texture variables (Contrast, cystic and necrosis, 'Rosette' changes, and 'incision sign') in the model of Logistic regression. Binary Logistic regression analysis demonstrated that cystic and necrosis changes, 'Rosette' changes and 'incision sign' and texture Contrast could be considered as the specific texture variables for the differential diagnosis of glioblastoma and primary CNS lymphoma.Conclusions The texture features of T2WI and conventional imaging findings may be used to distinguish glioblastoma from primary CNS lymphoma.

MRI Histogram Texture Feature Analysis of the Optic Nerve in the Patients with Optic Neuritis / 中国医学科学杂志(英文版)

Objective To evaluate the optic nerve impairment using MRI histogram texture analysis in the patients with optic neuritis.Methods The study included 60 patients with optic neuritis and 20 normal controls. The coronal T2 weighted imaging (T2WI) with fat saturation and enhanced T1 weighted imaging (T1WI) were performed to evaluate the optic nerve. MRI histogram texture features of the involved optic nerve were measured on the corresponding coronal T2WI images. The normal optic nerve (NON) was measured in the posterior 1/3 parts of the optic nerve. Kruskal-Wallis one-way ANOVA was used to compare the difference of texture features and receiver operating characteristic (ROC) curve were performed to evaluate the diagnostic value of texture features for the optic nerve impairment among the affected optic nerve with enhancement (ONwEN), affected optic nerve without enhancement (ONwoEN), contralateral normal appearing optic nerve (NAON) and NON.Results The histogram texture Energy and Entropy presented significant differences for ONwEN vs. ONwoEN (both P=0.000), ONwEN vs. NON (both P=0.000) and NAON vs. NON (both P<0.05). ROC analysis demonstrated that the area under the curve (AUC) of histogram texture Energy were 0.758, 0.795 and 0.701 for ONwEN vs. ONwoEN, ONwEN vs. NON and NAON vs. NON, AUC of Entropy were 0.758, 0.795 and 0.707 for ONwEN vs. ONwoEN, ONwEN vs. NON and NAON vs. NON.Conclusions The altered MRI histogram texture Energy and Entropy could be considered as a surrogate for MRI enhancement to evaluate the involved optic nerve and normal-appearing optic nerve in optic neuritis.

Value of Magnetic Resonance Imaging Texture Analysis in the Differential Diagnosis of Benign and Malignant Breast Tumors / 中国医学科学杂志(英文版)

Objective To investigate the difference in texture features on diffusion weighted imaging (DWI) images between breast benign and malignant tumors.Methods Patients including 56 with mass-like breast cancer, 16 with breast fibroadenoma, and 4 with intraductal papilloma of breast treated in the Hainan Hospital of Chinese PLA General Hospital were retrospectively enrolled in this study, and allocated to the benign group (20 patients) and the malignant group (56 patients) according to the post-surgically pathological results. Texture analysis was performed on axial DWI images, and five characteristic parameters including Angular Second Moment (ASM), Contrast, Correlation, Inverse Difference Moment (IDM), and Entropy were calculated. Independent sample t-test and Mann-Whitney U test were performed for intergroup comparison. Regression model was established by using Binary Logistic regression analysis, and receiver operating characteristic curve (ROC) analysis was carried out to evaluate the diagnostic efficiency.Results The texture features ASM, Contrast, Correlation and Entropy showed significant differences between the benign and malignant breast tumor groups (P=0.014, P=0.019, P=0.010, P=0.007). The area under the ROC curve was 0.685, 0.681, 0.754, and 0.683 respectively for the positive texture variables mentioned above, and that for the combined variables (ASM, Contrast, and Entropy) was 0.802 in the model of Logistic regression. Binary Logistic regression analysis demonstrated that ASM, Contrast and Entropy were considered as the specific imaging variables for the differential diagnosis of breast benign and malignant tumors.Conclusions The texture analysis of DWI may be a simple and effective tool in the differential diagnosis between breast benign and malignant tumors.

Magnetic Resonance Imaging Features of the Supratentorial Extra-axial Hemangioblastoma:A Case Report / 中国医学科学院学报

We reported a case of supratentorial extra-axial hemangioblastoma diagnosed by magnetic resonance imaging (MRI). As a simple solid mass,this tumor has its unique MRI features due to its tissue structures.

Spinal Schwannoma with Entering-and-exiting-nerve Sign:Report of One Case / 中国医学科学院学报

Peripheral neurogenic tumors can be featured by entering-and-exiting-nerve sign,which,however,is rarely seen in patients with spinal schwannoma. In this article we report a spinal schwannoma case with entering-and-exiting-nerve sign.

Gray Matter Volume Changes over the Whole Brain in the Bulbar- and Spinal-onset Amyotrophic Lateral Sclerosis: a Voxel-based Morphometry Study / 中国医学科学杂志(英文版)

Objective To investigate cerebral structural signatures of the bulbar- and spinal-onset amyotrophic lateral sclerosis (ALS) using voxel-based morphometry on magnetic resonance imaging. Methods The MR structural images of the brain were obtained from 65 ALS patients (15 bulbar-onset, 50 spinal-onset) and 65 normal controls (NC) on a 3.0T MRI system. Gray matter (GM) volume changes were investigated by voxel-based morphometry, and the distribution of the brain regions with volume changes was compared between ALS and normal controls, as well as between bulbar-onset and spinal-onset ALS based on Neuromorphometrics atlas. Result On voxel-level the decreased volume of brain regions in ALS patients was located in the right precentral gyrus (rPrcGy) and right middle frontal gyrus compared with that in NC. The bulbar-onset ALS presented extra-motor cortex atrophy (fronto-temporal pattern), including left medial orbital gyrus, left inferior temporal gyrus and right middle temporal gyrus; the spinal-onset ALS suffered from motor cortex atrophy (rPrcGy dominance) and extra-motor cortex atrophy (fronto-temporal and extra-fronto-temporal pattern) compared with NC. The spinal-onset ALS featured by GM volume loss of left postcentral gyrus and bulbar-onset ALS featured by GM volume loss of left middle temporal gyrus compared with each other. Conclusions The asymmetric GM atrophy of the motor cortex and extra-motor cortex represents the common MRI structural signatures of spinal-onset ALS, and sole extra-motor cortex atrophy represents the structural signatures of bulbar-onset ALS. The present study also demonstrated that the pattern of GM damage is likely to distribute wider in spinal-onset ALS than in bulbar-onset ALS.

Reliability of Three Dimentional Pseudo-continuous Arterial Spin Labeling: A Volumetric Cerebral Perfusion Imaging with Different Post-labeling Time and Functional State in Health Adults / 中国医学科学杂志(英文版)

Objective To evaluate the reliability of three dimensional spiral fast spin echo pseudo-continuous arterial spin labeling (3D pc-ASL) in measuring cerebral blood flow (CBF) with different post-labeling delay time (PLD) in the resting state and the right finger taping state. Methods 3D pc-ASL and three dimensional T1-weighted fast spoiled gradient recalled echo (3D T1-FSPGR) sequence were applied to eight healthy subjects twice at the same time each day for one week interval. ASL data acquisition was performed with post-labeling delay time (PLD) 1.5 seconds and 2.0 seconds in the resting state and the right finger taping state respectively. CBF mapping was calculated and CBF value of both the gray matter (GM) and white matter (WM) was automatically extracted. The reliability was evaluated using the intraclass correlation coefficient (ICC) and Bland and Altman plot. Results ICC of the GM (0.84) and WM (0.92) was lower at PLD 1.5 seconds than that (GM, 0.88; WM, 0.94) at PLD 2.0 seconds in the resting state, and ICC of GM (0.88) was higher in the right finger taping state than that in the resting state at PLD 1.5 seconds. ICC of the GM and WM was 0.71 and 0.78 for PLD 1.5 seconds and PLD 2.0 seconds in the resting state at the first scan, and ICC of the GM and WM was 0.83 and 0.79 at the second scan, respectively. Conclusion This work demonstrated that 3D pc-ASL might be a reliable imaging technique to measure CBF over the whole brain at different PLD in the resting state or controlled state.