Differentiation of retroperitoneal paragangliomas and schwannomas based on computed tomography radiomics

The purpose of this study was to differentiate the retroperitoneal paragangliomas and schwannomas using computed tomography (CT) radiomics. This study included 112 patients from two centers who pathologically confirmed retroperitoneal pheochromocytomas and schwannomas and underwent preoperative CT examinations. Radiomics features of the entire primary tumor were extracted from non-contrast enhancement (NC), arterial phase (AP) and venous phase (VP) CT images. The least absolute shrinkage and selection operator method was used to screen out key radiomics signatures. Radiomics, clinical and clinical-radiomics combined models were built to differentiate the retroperitoneal paragangliomas and schwannomas. Model performance and clinical usefulness were evaluated by receiver operating characteristic curve, calibration curve and decision curve. In addition, we compared the diagnostic accuracy of radiomics, clinical and clinical-radiomics combined models with radiologists for pheochromocytomas and schwannomas in the same set of data. Three NC, 4 AP, and 3 VP radiomics features were retained as the final radiomics signatures for differentiating the paragangliomas and schwannomas. The CT characteristics CT attenuation value of NC and the enhancement magnitude at AP and VP were found to be significantly different statistically (P < 0.05). The NC, AP, VP, Radiomics and clinical models had encouraging discriminative performance. The clinical-radiomics combined model that combined radiomics signatures and clinical characteristics showed excellent performance, with an area under curve (AUC) values were 0.984 (95% CI 0.952-1.000) in the training cohort, 0.955 (95% CI 0.864-1.000) in the internal validation cohort and 0.871 (95% CI 0.710-1.000) in the external validation cohort. The accuracy, sensitivity and specificity were 0.984, 0.970 and 1.000 in the training cohort, 0.960, 1.000 and 0.917 in the internal validation cohort and 0.917, 0.923 and 0.818 in the external validation cohort, respectively. Additionally, AP, VP, Radiomics, clinical and clinical-radiomics combined models had a higher diagnostic accuracy for pheochromocytomas and schwannomas than the two radiologists. Our study demonstrated the CT-based radiomics models has promising performance in differentiating the paragangliomas and schwannomas.

GSI CTA evaluation of the vertebrobasilar artery in normal adults at high altitude

Objective

Vascular geometry is influenced by several factors during its growth and development. Here, we compared the differences in vertebrobasilar geometry among residents of a plateau region at different altitudes and investigated the relationship between vascular geometry and altitude.

Methods

Data of some adults in the plateau region who experienced vertigo and headache as the main symptoms but had no evident abnormalities found during imaging examination were collected. They were divided into three groups based on an altitude gradient: group A (1,800-2,500 masl), group B (2,500-3,500 masl), and group C (over 3,500 masl). They underwent head-neck energy-spectrum computed tomography angiography with a gemstone spectral imaging scanning protocol. The following indices were observed: (1) vertebrobasilar geometric configurations (walking, tuning fork, lambda, and no confluence), (2) vertebral artery (VA) hypoplasia, (3) the bending number of bilateral VA intracranial segment, (4) length and tortuosity of the basilar artery (BA), and (5) anteroposterior (AP)-mid-BA angle, BA-VA angle, lateral-mid-BA angle, and VA-VA angle.

Results

Of the 222 subjects, 84 of them were included in group A, 76 in group B, and 62 in group C. The number of participants in walking, tuning fork, lambda, and no confluence geometries was 93, 71, 50, and 8, respectively. As altitude increased, the tortuosity of the BA also increased (1.05 ± 0.06 vs. 1.06 ± 0.08 vs. 1.10 ± 0.13, P = 0.005), as did the lateral-mid-BA angle (23.18° ± 9.53° vs. 26.05° ± 10.10° vs. 31.07° ± 15.12°, P = 0.007) and the BA-VA angle (32.98° ± 17.85° vs. 34.51° ± 17.96° vs. 41.51° ± 19.22°, P = 0.024). There was a relatively weak positive correlation between the altitude and the tortuosity of the BA (r_s= 0.190, P = 0.005), the lateral-mid-BA angle (r_s= 0.201, P = 0.003), and the BA-VA angle (r_s= 0.183, P = 0.006) which showed a significant difference. Compared with groups A and B, there were more multibending groups and fewer oligo-bending groups in group C (P < 0.001). There was no difference found in the vertebral artery hypoplasia, actual length of the BA, VA-VA angle, and AP-mid-BA angle among the three groups.

Conclusion

As the altitude increased, the tortuosity of the BA and the sagittal angle of the vertebrobasilar arterial system also increased. The increase in altitude can lead to changes in vertebrobasilar geometry.

Study of high-altitude cerebral edema using multimodal imaging

Objective

To analyze the brain imaging features of high-altitude cerebral edema (HACE) using computed tomography (CT) and multi-sequence magnetic resonance imaging (MRI) and to explore its injury characteristics.

Materials and methods

We selected 30 patients with HACE diagnosed between January 2012 to August 2022 as the experimental group and 60 patients with dizziness on traveling from the plain to the plateau or from lower altitude to higher altitude in a short period of time as the control group. We collected general clinical data from the experimental group and classified it according to clinical symptoms. In both groups, we then performed a head CT and multi-sequence MRI (T1WI, T2WI, FLAIR, and DWI). Among them, nine patients with HACE were also scanned using susceptibility-weighted imaging (SWI). Finally, we analyzed the images.

Results

According to clinical symptoms, we divided the 30 cases of HACE into 12 mild cases and 18 severe cases. There was no significant difference in sex, age, leukocyte, neutrophil, or glucose content between mild and severe HACE. The sensitivity and specificity of the MRI diagnosis were 100 and 100%, respectively, while the sensitivity and specificity of the CT diagnosis were 23.3 and 100%, respectively. The distribution range of deep and juxtacortical white matter edema was significantly larger in severe HACE than in mild HACE (p < 0.001). The corpus callosum edema distribution range in severe HACE was significantly larger than that in mild HACE (p = 0.001). The ADC value of the splenium of the corpus callosum was significantly lower in severe HACE than in mild HACE (p = 0.049). In mild and severe HACE, the signal intensity of the DWI sequence was significantly higher than that of conventional MRI sequences (T1WI, T2WI, FLAIR) (p = 0.008, p = 0.025, respectively). In severe HACE, seven cases showed bilateral corticospinal tract edema at the thalamic level, and SWI showed cerebral microbleeds (CMBs) in five cases, especially in the corpus callosum.

Conclusions

MRI has more advantages than CT in the evaluation of HACE, especially in the DWI sequence. The white matter injury of severe HACE is more severe and extensive, especially in the corpus callosum, and some CMBs and corticospinal tract edema may also appear.

Magnetic resonance imaging study of normal cranial bone marrow conversion at high altitude

BACKGROUND

To use conventional magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) to investigate the effects of long-term hypoxia on cranial bone marrow conversion in healthy people at high altitudes.

METHODS

A total of 1,130 individuals were selected from altitudinal areas of 2,000-3,000, 3,100-4,000, and >4,100 m. Each altitude range was divided into 5 age groups: 0-5, 6-14, 15-29, 30-49, and ≥50 years. Firstly, cranial bone marrow typing of the participants in each altitude range was performed on sagittal T1-weighted images (T1WI) according to the average diploe thickness and signal intensity of the normal skull, and the relationship between bone marrow conversion and age was analyzed. Secondly, the apparent diffusion coefficient (ADC) values of the frontal bone, parietal bone, occipital bone, and temporal bone were measured in the DWI post-processing workstation and statistical methods were used to analyze whether different altitudinal gradients and long-term hypoxic environment had any effect on cranial bone marrow conversion.

RESULTS

There was a positive correlation between bone marrow type and age in the healthy populations at all 3 levels of altitude (P<0.05). The average thickness of the cranial diploe also positively correlated with age (P<0.05); in the age ranges of 30-49 and ≥50 years, the ADC values of the occipital and temporal bone marrow positively correlated with increasing altitude (P<0.05).

CONCLUSIONS

The cranial bone marrow of normal people at high altitudes changes from Type I to Type IV with increasing age and under the influence of long-term chronic hypoxia. The bone marrow of the occipital and temporal bones of healthy people aged 30-49 and ≥50 years showed erythromedularization during the process of Type III and IV bone marrow conversion.

Study of Brain Structure and Function in Chronic Mountain Sickness Based on fMRI

Objective: Headache and memory impairment are the primary clinical symptoms of chronic mountain sickness (CMS). In this study, we used voxel-based morphometry (VBM) and the amplitude of the low-frequency fluctuation method (ALFF) based on blood oxygen level-dependent functional magnetic resonance imaging (BOLD-fMRI) to identify changes in the brain structure and function caused by CMS.

Materials and Methods: T1W anatomical images and a resting-state functional MRI (fMRI) of the whole brain were performed in 24 patients diagnosed with CMS and 25 normal controls matched for age, sex, years of education, and living altitude. MRI images were acquired, followed by VBM and ALFF data analyses.

Results: Compared with the control group, the CMS group had increased gray matter volume in the left cerebellum crus II area, left inferior temporal gyrus, right middle temporal gyrus, right insula, right caudate nucleus, and bilateral lentiform nucleus along with decreased gray matter volume in the left middle occipital gyrus and left middle temporal gyrus. White matter was decreased in the bilateral middle temporal gyrus and increased in the right Heschl's gyrus. Resting-state fMRI in patients with CMS showed increased spontaneous brain activity in the left supramarginal gyrus, left parahippocampal gyrus, and left middle temporal gyrus along with decreased spontaneous brain activity in the right cerebellum crus I area and right supplementary motor area.

Conclusion: Patients with CMS had differences in gray and white matter volume and abnormal spontaneous brain activity in multiple brain regions compared to the controls. This suggests that long-term chronic hypoxia may induce changes in brain structure and function, resulting in CMS.

Predicting Microsatellite Instability Status in Colorectal Cancer Based on Triphasic Enhanced Computed Tomography Radiomics Signatures: A Multicenter Study

Background

This study aimed to develop and validate a computed tomography (CT)-based radiomics model to predict microsatellite instability (MSI) status in colorectal cancer patients and to identify the radiomics signature with the most robust and high performance from one of the three phases of triphasic enhanced CT.

Methods

In total, 502 colorectal cancer patients with preoperative contrast-enhanced CT images and available MSI status (441 in the training cohort and 61 in the external validation cohort) were enrolled from two centers in our retrospective study. Radiomics features of the entire primary tumor were extracted from arterial-, delayed-, and venous-phase CT images. The least absolute shrinkage and selection operator method was used to retain the features closely associated with MSI status. Radiomics, clinical, and combined Clinical Radiomics models were built to predict MSI status. Model performance was evaluated by receiver operating characteristic curve analysis.

Results

Thirty-two radiomics features showed significant correlation with MSI status. Delayed-phase models showed superior predictive performance compared to arterial- or venous-phase models. Additionally, age, location, and carcinoembryonic antigen were considered useful predictors of MSI status. The Clinical Radiomics nomogram that incorporated both clinical risk factors and radiomics parameters showed excellent performance, with an AUC, accuracy, and sensitivity of 0.898, 0.837, and 0.821 in the training cohort and 0.964, 0.918, and 1.000 in the validation cohort, respectively.

Conclusions

The proposed CT-based radiomics signature has excellent performance in predicting MSI status and could potentially guide individualized therapy.

Resting-state functional magnetic resonance imaging of high altitude patients with obstructive sleep apnoea hypopnoea syndrome

The objective of the study was to observe brain function changes in Obstructive Sleep Apnoea Hypopnoea Syndrome (OSAHS) patients at high altitude. Resting-state functional magnetic resonance imaging (rs-fMRI) in patients with OSAHS was assessed using regional homogeneity (ReHo), amplitude of low frequency fluctuation (ALFF) and functional connectivity (FC). In this study, 36 male patients with OSAHS and 38 healthy male subjects were recruited from high-altitude areas, specifically, altitudes of 2,000–3,000 m. OSAHS was diagnosed by polysomnography (PSG). The blood oxygen level-dependent (BOLD) signals of OSAHS patients and healthy controls in the resting state were obtained and compared using ReHo, ALFF and FC methods. The posterior cingulate cortex (PCC) was selected as the seed region in the comparison of FC between the two groups. Compared with the healthy control group, multiple brain functions in the OSAHS patient group were different. There were correlations between the brain function values of some brain regions and demographic data. We also found that in contrast to earlier findings with individuals in plains areas, the brain function at the frontal lobe and the precuneus were higher in OSAHS patients, and the PCC showed higher FC with the left caudate, which may be due to the high-altitude hypoxic environment.

Evaluation of intrahepatic manifestation and distant extrahepatic disease in alveolar echinococcosis

BACKGROUND

The main endemic areas of alveolar echinococcosis (AE) are in Central Europe and Western China. Both the infiltration of intrahepatic vascular and bile duct structures as well as extrahepatic disease can lead to further complications and may increase morbidity in patients with AE.

AIM

To evaluate vascular/biliary involvement in hepatic AE and its distant extrahepatic disease manifestations in an international collective was the aim.

METHODS

Consecutively, five experienced examiners evaluated contrast-enhanced abdominal computed tomography (CT) scans for 200 patients with hepatic AE of each of four locations (n = 50) in Germany, France and China. Therefore, we retrospectively included the 50 most recent abdominal contrast-enhanced CT examinations at each center, performed because of hepatic AE from September 21, 2007 to March 21, 2018. AE liver lesions were classified according to the echinococcosis multilocularis Ulm classification for CT (EMUC-CT). Distant extrahepatic manifestations were documented either by whole body positron emission tomography–CT or with the addition of thoracic CT and cranial magnetic resonance imaging. Vascular/biliary involvement of the hepatic disease as well as the presence of distant extrahepatic manifestations were correlated with the EMUC-CT types of liver lesion. Statistical analysis was performed using SAS Version 9.4 (SAS Institute Inc., Cary, NC, United States).

RESULTS

Distant extrahepatic AE manifestations were significantly more frequent in China than in Europe (P = 0.0091). A significant relationship was found between the presence of distant extrahepatic disease and AE liver lesion size (P = 0.0075). Vascular/biliary structures were involved by the liver lesions significantly more frequently in China than in Europe (P < 0.0001), and vascular/biliary involvement depended on lesion size. Different morphological types of AE liver lesions led to varying frequencies of vascular/biliary involvement and were associated with different frequencies of distant extrahepatic manifestations: Vascular/biliary involvement as a function of lesions primary morphology ranged from 5.88% of type IV liver lesions to 100% among type III lesions. Type IV differed significantly in these associations from types I, II, and III (P < 0.0001). With respect to extrahepatic disease, the primary morphology types IV and V of liver lesions were not associated with any case of distant extrahepatic disease. In contrast, distant extrahepatic manifestations in types I–III were found to varying degrees, with a maximum of 22% for type III.

CONCLUSION

Different CT morphological patterns of hepatic AE lesions influence vascular/biliary involvement and the occurrence of distant extrahepatic manifestations. There are intercontinental differences regarding the characteristics of AE manifestation.

Brain functional changes in tibetan with obstructive sleep apnea hypopnea syndrome: A resting state fMRI study

Tibetan is a major ethnic group living on the Qinghai-Tibet Plateau in China. Due to their high-altitude hypoxia environment, sleeping disorder and obstructive sleep apnea hypopnea syndrome (OSAHS) are more prone to occur. In this study, we investigated the brain structural and functional differences between Tibetans OSAHS patients and Tibetans healthy controls using high resolution three-dimensional T1 weighted magnetic resonance imaging (MRI) and resting state functional MRI. The analysis was based on voxel-based morphology, regional homogeneity (ReHo), amplitude of low-frequence fluctuation (ALFF) and functional connection (FC) methods. A total of 14 OSAHS patients and 16 healthy control, all Tibetan male, matched closely in terms of age, education and living altitude, were recruited. The relationship between the ReHo and ALFF values at different brain areas and clinical features, including the apnea hypopnea index (AHI) in the OSAHS group, was analyzed using Pearson correlation. Compared with healthy control, OSAHS patients showed no significant gray matter volume or FC change. OSAHS group showed significantly increased ReHo values in the superior frontal gyrus dorsolateral, the left middle frontal gyrus, and the superior frontal gyrus medial. In contrast, OSAHS group showed decreased ReHo value in the left fusiform gyrus and cerebellum lobule 6. OSAHS group showed significantly increased ALFF values in the right inferior frontal gyrus orbital part, the right median cingulate and paracingulate gyri, the right Inferior frontal gyrus triangular part, the right insula and the left superior frontal gyrus dorsolateral. In the OSAHS group, the AHI showed a positive correlation with the ReHo value at the left cerebellum lobule 6 (r = 0.562, P = .037). Tibetan OSAHS patients had no significant change in brain structure and FC, which may be due to their adaption to the hypoxia environment. ReHo values and ALFF values changes in multiple brain areas in Tibetan OSAHS patients indicated brain functional impairment in multiple brain regions. The left cerebellum lobule 6 gradually compensates brain function as OSAHS progresses.

DTI Study on Brain Structure and Cognitive Function in Patients with Chronic Mountain Sickness

In chronic mountain sickness (CMS) patients, the structure of the brain, memory and cognition are often irreversibly damaged by chronic hypoxia due to red blood cell overcompensation, elevated haemoglobin and blood stasis. In this study, we aimed to evaluate this damage using diffusion tensor imaging (DTI) and to study the correlations among the fractional anisotropy (FA),the apparent diffusion coefficient (ADC) value, the severity index of CMS and the simple Mental State Examination (MMSE) score in CMS patients. A total of 17 patients with CMS and 15 healthy controls were recruited for conventional brain magnetic resonance imaging (MRI) and DTI scans, and ADC images were reconstructed along with FA and FA colour maps. The FA and ADC values of the selected regions of interest (ROIs) were measured and compared. The FA and ADC values were also compared with the haemoglobin (Hb) and MMSE scores. CMS patients are prone to intracranial ischaemia, infarction and haemorrhage. Multiple structural changes occur in the brain of CMS patients, and these changes are related to the severity of the disease and cognitive function variation. The white matter fibre bundles of CMS patients showed no obvious damage, except in the ischaemic site.

Magnetic resonance imaging evaluation of characteristics of vascular invasion in intermediate and advanced hepatic alveolar echinococcosis

The objective of the present study was to provide a basis for the personalized treatment of intermediate and advanced hepatic alveolar echinococcosis (HAE) by elucidating the characteristics of vascular invasion and lesion growth. A total of 160 patients with intermediate and advanced HAE who were subjected to plain as well as contrast-enhanced 3.0-T magnetic resonance imaging prior to surgery were analyzed. Pathological and intra-operative observations of the subjects were also considered. The size and location of HAE lesions, vascular invasion characteristics and growth patterns were assessed. A total of 78 patients (48.75%) had lesions involving the S5-8 segment/partial right liver lobe, 21 (13.13%) had involvement in the S2-4 segment/partial left liver lobe and 61 (38.13%) had lesions that transcended the left and right liver lobes. Pathological examination revealed that the vascular invasion rates of the hepatic portal veins, intrahepatic veins (left, central and right vein, and inferior vena cava) and hepatic arteries were 51.88, 43.28 and 26.87%, respectively. Liver hilum invasion was observed in 128 patients (80.00%), 71 of which (44.38%) presented with invasion of the primary porta hepatis, 11 (6.88%) with invasion of the secondary porta hepatis and 46 (28.75%) with invasion of the primary as well as the secondary porta hepatis. In conclusion, the growth pattern of intermediate and advanced HAE is determined by the site, blood supply and activity of the lesion. The current study demonstrated that lesions tend to invade the intrahepatic venous system and porta hepatis, and to target veins rather than arteries.