MRI image-based FE modelling of the pelvis system and bladder filling

In this study, high-resolution magnetic resonance imaging was performed in the transaxial, coronal and sagittal planes to provide comprehensive structural details of the bladder and surrounding systems. Detailed finite-element (FE) models that were specific to each participant were developed by rendering the images, and the process of bladder filling was simulated. The overall model of bladder deformation was compared with repeated images of the filled bladder that were obtained using computed tomography to validate the FE models. The relationship between the changes in the key dimensions of the bladder and the increase in bladder volume during the filling process was also investigated. The numerical results showed that the bladder dimensions increased linearly with its volume during the filling process and the predicted coefficients are comparable to some of the published clinical results.     

腰椎间盘突出症的CT及MRI诊断

目的：总结分析１９１例腰椎间盘突出症的ＣＴ及ＭＲＩ影像特征。方法：ＣＴ组１０４例,ＭＲＩ组８７例,同时行ＣＴ及ＭＲ检查４４例。结果：ＣＴ组中,椎间盘同位于Ｌ３－４者１２例,Ｌ４－５者３２例,Ｌ５－Ｓ１者６０例。骨质增生３１例,髓核钙化１１例,后纵韧带钙化９例。ＭＲ组中,椎间盘突出位于Ｌ３－４者１３例,Ｌ４－５者３９例,Ｌ５－Ｓ１者３５例,椎间盘突变性４１例。     

CT scan reconstruction of the palate region of Latimeria chalumnae

Synopsis The palate of Latimeria chalumnae is described based mainly on three-dimensional CT scan reconstruction. It is compared with that of other osteichthyans. The palate of L. chalumnae compares best with that of rhipidistians; it is more advanced than that of actinopterygians in having fewer bones. This tendency toward bone reduction in the palate is even more pronounced in dipnoans. The interpretation of features of the Early Devonian genus Diabolepis determines if authors consider dipnoans or actinistians more closely related to tetrapods. Both groups are only distant relatives of tetrapods.     

Evaluation of velopharyngeal closure by CT scan and endoscopy

Computerized tomography (CT) and endoscopy were used for the objective evaluation of velopharyngeal closure. In 19 patients with cleft palates and 9 normal subjects, CT scans of the velopharynx were made both at rest and during vowel phonation with a scanning time of 3.0 seconds and slicing width of 3 mm. At the same time, endoscopic observations of the velopharynx through the nose were carried out both at rest and during phonation. CT scan during phonation clearly demonstrated the mobility of the velopharynx, i.e., elevation of the soft palate, inward movement of the lateral pharyngeal walls, and protrusion of the posterior pharyngeal wall, in a single picture. Its disadvantage is exposure to x-rays and a rather complicated procedure. However, endoscopy is simple with no exposure to x-rays, but its disadvantage is occasional incomplete visualization because of the dead angle created by the elevated soft palate. Thus the combined use of CT and endoscopy can help to determine a rational choice of treatment for cleft palates.     

Magnetic resonance imaging (MRI) in the diagnosis of recurrences of ovarian cancer in the small pelvis

The paper provides the results of small pelvic magnetic resonance tomography (MRI) in 62 patients with ovarian cancer after primary special treatment. Out of them 50 patients were found to have recurrences and metastases of the underlying disease, 12 patients had clinical remission. The study yielded MR signs and MR semiotics of recurrences of ovarian cancer in the small pelvis. The capacities of MRI with low and high intensities of a magnetic field were comparatively studied in the diagnosis of recurrences and metastases of ovarian cancer.     

Analysis of the capital femoral line orientation. A CT scan study

An accurate knowledge of the relationship between the neck and the epiphyseal plate at the end of growth is important for biomechanical investigations of femoral neck remodelling during childhood. Statistical data about the position of the epiphyseal femoral cartilage in relation to the neck axis at the end of the growth, are rare in the literature. As the trace of the epiphysis can be observed on a CT scan view of an adult hip, cadaver femurs were investigated to study this relationship and to avoid irradiation of children. The mean anteversion angle of the epiphyseal line towards the patient's coronal plane is 2.3 degrees. The plate is retroverted in an average of 8.2 degrees in relation to the neck axis and is related to neck anteversion. The more the neck is anteverted, the more the plate is retroverted.     

PETER PHAN: An MRI phantom for the optimisation of radiomic studies of the female pelvis

PurposeTo develop a phantom for methodological radiomic investigation on Magnetic Resonance (MR) images of female patients affected by pelvic cancer.MethodsA pelvis-shaped container was filled with a MnCl₂ solution reproducing the relaxation times (T₁, T₂) of muscle surrounding pelvic malignancies. Inserts simulating multi-textured lesions were embedded in the phantom. The relaxation times of muscle and tumour were measured on an MR scanner on healthy volunteers and patients; T₁ and T₂ of MnCl₂ solutions were evaluated with a relaxometer to find the concentrations providing a match to in vivo relaxation times. Radiomic features were extracted from the phantom inserts and the patients’ lesions. Their repeatability was assessed by multiple measurements.ResultsMuscle T₁ and T₂ were 1128 (806–1378) and 51 (40–65) ms, respectively. The phantom reproduced in vivo values within 13% (T₁) and 12% (T₂). T₁ and T₂ of tumour tissue were 1637 (1396–2121) and 94 (79–101) ms, respectively. The phantom insert best mimicking the tumour agreed within 7% (T₁) and 24% (T₂) with in vivo values. Out of 1034 features, 75% (95%) had interclass correlation coefficient greater than 0.9 on T₁ (T₂)-weighted images, reducing to 33% (25%) if the phantom was repositioned. The most repeatable features on phantom showed values in agreement with the features extracted from patients’ lesions.ConclusionsWe developed an MR phantom with inserts mimicking both relaxation times and texture of pelvic tumours. As exemplified with repeatability assessment, such phantom is useful to investigate features robustness and optimise the radiomic workflow on pelvic MR images.     

CT联合MRI在早期肝癌诊断临床价值分析

摘要 目的：探究CT联合MRI在早期肝癌诊断中的应用价值。方法：选择2016年6月至2019年6月于我院接受诊断治疗的78例已知或疑似肝癌患者,分别对其实施CT及MRI检测,以病灶部位病理学检查结果为金标准（50例确诊为早期肝癌,28例为良性病变）,分别评估CT、MRI、CT联合MRI对早期肝癌的诊断价值,将确诊为肝癌的50例患者按照病灶大小区分为直径≤3 cm组（21例）和>3 cm组（29例）,对比CT与MRI对不同直径肝癌诊断率。结果：（1）检测发现,CT对早期肝癌诊断一致性为73.08 %,灵敏度为72.00 %,特异度为75.00 %;（2）MRI对早期肝癌诊断一致性为82.05 %,灵敏度为82.00 %,特异度为82.14 %;（3）CT联合MRI检测对早期肝癌诊断一致性为93.59 %,灵敏度为92.00 %,特异度为96.43 %;（4）对比发现,对直径≤3 cm的早期肝癌患者,MRI诊断率明显高于CT（95.24 % vs 76.19 %,P<0.05）。结论：CT及MRI对早期肝癌均具有较好的诊断价值,但联合检测明显优于任一单独检测,同时对病灶直径≤3 cm的早期肝癌患者,MRI诊断准确率更高。     

Role of CT scan in theranostic and management of traumatic spinal cord injury

Traumatic spinal cord injury (TSCI) is a condition with suffering of neural structures from acute trauma with short-term or permanent sensory and motor problems. This study was conducted with the aim of determining the prevalence of TSCI in Tehran with emphasis on demographic characteristics of patients and to evaluate the effect of computed tomography (CT) in determining fracture type and severity grade of injury among TSCI patients. In a cross-sectional study, all TSCI and spinal fracture patients (N = 520) who referred to the main trauma center in Tehran, Iran, in 2013 and 2014 were selected. Radiography and CT scan were prepared and reported blindedly by two radiologists. Majority of the patients was 21–30 years male, married and their most common occupation was car driver. A significant difference was observed between gender and etiology (P = 0.001). The main etiology was traffic accident followed by falling from height. While the most common location of injury for males was thoracic vertebrae followed by lumbar vertebrae; for females it was lumbar followed by thoracic. Majority of patients had ASIA (American Spinal Injury Association) impairment scale of E (normal), followed by B (sensory incomplete). Most of the cases were hospitalized less than one week. Age of the patient and duration of hospitalization had a significant association (P = 0.015). The results showed that in traumatic spinal cord events, traffic accident and falling from height are the main etiologies; hence, authorities in Iranian health system could consider preventive policies to decline the load and TSCI effects in hospitals and population.     

Incidence and cytological features of pulmonary hamartomas indeterminate on CT scan

Objective:  Pulmonary hamartomas have a characteristic heterogeneous radiological appearance. However, when composed predominantly of undifferentiated mesenchymal fibromyxoid component, their homogeneous appearance on computed tomography is indeterminate for malignancy. Rendering an accurate preoperative diagnosis in these cases can alter management. The aim of this study was to determine the incidence and accuracy of cytodiagnosis for hamartomas 'indeterminate' by imaging.
Methods:  We retrospectively reviewed records for hamartomas diagnosed by transthoracic fine needle aspiration (FNA) including immediate impressions and final diagnoses. Cytological features evaluated included the presence of fibromyxoid stroma, bronchioloalveolar cell hyperplasia, fibroadipose tissue, cartilage and smooth muscle.
Results:  Eighteen (1.3%) hamartomas were identified from 1355 transthoracic FNAs. The immediate impression was hamartoma in 13 (72%), carcinoid in one (6%), mucinous bronchioloalveolar carcinoma in two (11%) and non-diagnostic in two (11%). The final diagnosis of hamartoma in cases diagnosed as carcinoid, mucinous bronchioloalaveolar carcinoma and non-diagnostic on immediate impression was rendered following assessment of all cytological material.
Conclusion:  Overall, FNAs are highly reliable for diagnosing hamartomas even when composed principally of undifferentiated mesenchymal fibromyxoid stroma, especially with the aid of all available preparations including Diff-Quik smears, Papanicolaou smears, ThinPreps and cell block material.     

胰腺神经内分泌肿瘤的不典型CT、MRI征象分析

目的:分析4例胰腺神经内分泌肿瘤(P-NENs)的不典型CT、MRI影像学特征,以提高对其诊断水平.方法:对4例经手术病理证实的P-NENs的不典型CT和(或)MRI表现进行回顾性分析.结果:4例胰腺神经内分泌肿瘤患者均进行CT平扫及增强检查,平扫病变相对于正常胰腺呈等密度1例,稍低密度3例,其中1例瘤内见钙化;CT增强扫描4例均为轻～中度增强,静脉期较动脉期增强幅度稍减低,所有患者各期增强幅度均未超过胰腺实质,其中1例可见延迟期不完整包膜强化,包膜密度略高于周围胰腺.3例患者行MRI平扫、DWI及增强检查,2例肿瘤相对正常胰腺呈长T1、稍长T2信号,较均匀,1例T1WI呈不均匀稍低信号,T2WI呈较高与稍低混杂信号,CT所显示之病变内钙化T1、T2均呈较低信号.DWI序列3例病变均呈较明显高信号.增强扫描3例病变均呈轻到中度强化,2例强化较均匀,1例强化不均匀,强化幅度均未超过正常胰腺.2例MRI可见有部分包膜环形强化,略高于周围胰腺实质.结论:明显增强以及包膜强化被认为是P-NENs的典型影像学表现,但其影像学表现多样,认识其多样性及不典型影像学征象,可以提高对其诊断准确率.     

Whole-genome scan, in a complex disease, using 11,245 single-nucleotide polymorphisms: comparison with microsatellites

Despite the theoretical evidence of the utility of single-nucleotide polymorphisms (SNPs) for linkage analysis, no whole-genome scans of a complex disease have yet been published to directly compare SNPs with microsatellites. Here, we describe a whole-genome screen of 157 families with multiple cases of rheumatoid arthritis (RA), performed using 11,245 genomewide SNPs. The results were compared with those from a 10-cM microsatellite scan in the same cohort. The SNP analysis detected HLA*DRB1, the major RA susceptibility locus (P=.00004), with a linkage interval of 31 cM, compared with a 50-cM linkage interval detected by the microsatellite scan. In addition, four loci were detected at a nominal significance level (P<.05) in the SNP linkage analysis; these were not observed in the microsatellite scan. We demonstrate that variation in information content was the main factor contributing to observed differences in the two scans, with the SNPs providing significantly higher information content than the microsatellites. Reducing the number of SNPs in the marker set to 3,300 (1-cM spacing) caused several loci to drop below nominal significance levels, suggesting that decreases in information content can have significant effects on linkage results. In contrast, differences in maps employed in the analysis, the low detectable rate of genotyping error, and the presence of moderate linkage disequilibrium between markers did not significantly affect the results. We have demonstrated the utility of a dense SNP map for performing linkage analysis in a late-age-at-onset disease, where DNA from parents is not always available. The high SNP density allows loci to be defined more precisely and provides a partial scaffold for association studies, substantially reducing the resource requirement for gene-mapping studies.     

The use of sparse CT datasets for auto-generating accurate FE models of the femur and pelvis

The finite element (FE) method when coupled with computed tomography (CT) is a powerful tool in orthopaedic biomechanics. However, substantial data is required for patient-specific modelling. Here we present a new method for generating a FE model with a minimum amount of patient data. Our method uses high order cubic Hermite basis functions for mesh generation and least-square fits the mesh to the dataset. We have tested our method on seven patient data sets obtained from CT assisted osteodensitometry of the proximal femur. Using only 12 CT slices we generated smooth and accurate meshes of the proximal femur with a geometric root mean square (RMS) error of less than 1 mm and peak errors less than 8 mm. To model the complex geometry of the pelvis we developed a hybrid method which supplements sparse patient data with data from the visible human data set. We tested this method on three patient data sets, generating FE meshes of the pelvis using only 10 CT slices with an overall RMS error less than 3 mm. Although we have peak errors about 12 mm in these meshes, they occur relatively far from the region of interest (the acetabulum) and will have minimal effects on the performance of the model. Considering that linear meshes usually require about 70-100 pelvic CT slices (in axial mode) to generate FE models, our method has brought a significant data reduction to the automatic mesh generation step. The method, that is fully automated except for a semi-automatic bone/tissue boundary extraction part, will bring the benefits of FE methods to the clinical environment with much reduced radiation risks and data requirement.     

Mechanical properties, density and quantitative CT scan data of trabecular bone with and without metastases

Pathologic fracture of the hip due to metastatic lesions in bone is a serious problem. This study examined the effect of metastatic lesions on the material properties and quantitative computed tomography (QCT) data of trabecular bone. Twelve distal femora were obtained, four with lytic and/or blastic metastatic lesions (group L), four without lesions but from donors who died from breast, prostate, or lung cancer (group NL), and four from donors with no cancer (group NC). Each specimen was CT scanned, and 56, 15x15x15-mm cubes of trabecular bone were cut. QCT density (rho(QCT)), compressive elastic modulus (E), compressive yield and ultimate strengths (S(y) and S(u)), and ash density (rho(ash)) of each cube were determined. Regression analysis was performed between rho(ash) and E, S(y), S(u) and rho(QCT), and analysis of covariance was used to identify differences between groups. Power relationships that did not depend on group (p >/= 0.1) were found between E and rho(ash) (0.74 /= 0.94; p<0.001). rho(ash) was strongly related to rho(QCT) (r >/= 0.99; p<0.001). These results indicate that metastatic disease does not significantly impair the ability of QCT to provide an accurate and precise estimate of rho(ash) that can be used to estimate mechanical properties of trabecular bone with and without metastases.     

CT和MRI鉴定腹膜后间隙脂肪肉瘤与组织病理学特征相关

本研究选取2012年1月至2018年1月在我院治疗的腹膜后间隙脂肪肉瘤患者33例,分析患者术前CT、MRI图像及术后病理结果,旨在探讨不同类型腹膜后间隙脂肪肉瘤病理学及影像学特征。研究结果表明:33例患者中术后病理诊断为高分化脂肪肉瘤19例,去分化脂肪肉瘤7例,黏液性脂肪肉瘤7例;不同病理分型脂肪肉瘤病灶大小比较差异无统计学意义(p>0.05);高分化脂肪肉瘤其CT密度同皮下脂肪,CT值-10～-110 Hu,肿瘤内可见不规则增厚的间隔;去分化脂肪肉瘤部分区域呈脂肪密度(CT值-70～30 Hu),部分区域呈软组织肿块(CT值为30～50 Hu);黏液性脂肪肉瘤CT密度接近水,增强扫描时肿块呈网状、片状、延迟强化,CT值20～40 Hu;高分化脂肪肉瘤MRI信号同皮下脂肪;黏液性脂肪肉瘤MRI呈长T1,长T2信号,与水相似;CT和MRI诊断腹膜后间隙脂肪瘤准确率分别为69.70%和73.33%,差异比较无统计学意义(p>0.05)。本研究得出初步结论,不同病理类型腹膜后间隙脂肪肉瘤的CT、MRI表现有所差异;CT和MRI术前诊断腹膜后间隙脂肪肉瘤准确性相似。