A meta-learning based method for segmentation of few-shot magnetic resonance images / 生物医学工程学杂志

When applying deep learning algorithms to magnetic resonance (MR) image segmentation, a large number of annotated images are required as data support. However, the specificity of MR images makes it difficult and costly to acquire large amounts of annotated image data. To reduce the dependence of MR image segmentation on a large amount of annotated data, this paper proposes a meta-learning U-shaped network (Meta-UNet) for few-shot MR image segmentation. Meta-UNet can use a small amount of annotated image data to complete the task of MR image segmentation and obtain good segmentation results. Meta-UNet improves U-Net by introducing dilated convolution, which can increase the receptive field of the model to improve the sensitivity to targets of different scales. We introduce the attention mechanism to improve the adaptability of the model to different scales. We introduce the meta-learning mechanism, and employ a composite loss function for well-supervised and effective bootstrapping of model training. We use the proposed Meta-UNet model to train on different segmentation tasks, and then use the trained model to evaluate on a new segmentation task, where the Meta-UNet model achieves high-precision segmentation of target images. Meta-UNet has a certain improvement in mean Dice similarity coefficient (DSC) compared with voxel morph network (VoxelMorph), data augmentation using learned transformations (DataAug) and label transfer network (LT-Net). Experiments show that the proposed method can effectively perform MR image segmentation using a small number of samples. It provides a reliable aid for clinical diagnosis and treatment.

Research on classification method of multimodal magnetic resonance images of Alzheimer's disease based on generalized convolutional neural networks / 生物医学工程学杂志

Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative disease. Neuroimaging based on magnetic resonance imaging (MRI) is one of the most intuitive and reliable methods to perform AD screening and diagnosis. Clinical head MRI detection generates multimodal image data, and to solve the problem of multimodal MRI processing and information fusion, this paper proposes a structural and functional MRI feature extraction and fusion method based on generalized convolutional neural networks (gCNN). The method includes a three-dimensional residual U-shaped network based on hybrid attention mechanism (3D HA-ResUNet) for feature representation and classification for structural MRI, and a U-shaped graph convolutional neural network (U-GCN) for node feature representation and classification of brain functional networks for functional MRI. Based on the fusion of the two types of image features, the optimal feature subset is selected based on discrete binary particle swarm optimization, and the prediction results are output by a machine learning classifier. The validation results of multimodal dataset from the AD Neuroimaging Initiative (ADNI) open-source database show that the proposed models have superior performance in their respective data domains. The gCNN framework combines the advantages of these two models and further improves the performance of the methods using single-modal MRI, improving the classification accuracy and sensitivity by 5.56% and 11.11%, respectively. In conclusion, the gCNN-based multimodal MRI classification method proposed in this paper can provide a technical basis for the auxiliary diagnosis of Alzheimer's disease.

Progress in TN staging of rectal cancer based on multimodal magnetic resonance imaging / 国际生物医学工程杂志

Rectal cancer is one of the most common gastrointestinal malignancies in China. Accurate and reasonable assessment of the preoperative staging of rectal cancer can significantly enhance treatment outcomes and improve patient prognosis. Magnetic resonance imaging is the technique of choice for local staging of rectal cancer and has significant advantages in the diagnosis of rectal primary tumors (T) and peri-intestinal lymph nodes (N). In this review paper, the research ideas and progress of traditional radiomics and deep learning methods for preoperative TN staging prediction of rectal cancer were reviewed around multimodal magnetic resonance images, with the aim of providing new ideas for realizing fully automated TN staging algorithms for rectal cancer.

A radiomic nomogram based on T2WI for predicting synchronous liver metastasis of rectal cancer / 中华放射学杂志

Objective To explore the clinical feasibility of predicting synchronous liver metastases based on MRI radiomics nomogram based on T2WI in rectal cancer. Methods The imaging and clinical data of 261 patients with primary rectal cancer admitted to Zhejiang People′s Hospital from April 2012 to May 2018 were retrospectively analyzed. 101 patients were accompanied by synchronous liver metastasis All cases were divided into training group (n=182) and verification group (n=79). T2WI image of each patient was selected to extract texture features by AK analysis software of GE company. A radiomics signature was constructed after reduction of dimension in training group by the least absolute shrinkage and selection operator (LASSO). Univariate logistic regression was used to select for independent clinical risk factors and multivariate logistic regression along with imaging omics tags were used to construct predictive models and nomogram. ROC was used to assess the accuracy of the nomogram in the training group and to verify them by the validation group. Finally, the clinical efficacy of each patient′s synchronized liver metastasis risk factor was calculated based on the nomogram. Results A total of 328 texture features were extracted from the T2WI. Seven most valuable features were selected after reducing the dimension by LASSO algorithm, including 3 co-occurrence matrices (GLCM) and 4 run-length matrices(RLM). Tumor staging and radiomic signatures were included in the Multifactor logistic regression to build the prediction model and nomogram. The accuracy of predicting SRLM was 0.862 and 0.844 in the training and the verification group, respectively. To evaluate the accuracy of the nomogram, radiomics signature and the tumor staging in all cases were 0.857, 0.832 and 0.663, respectively. There was no significant difference in the number of SRLM cases between the high risk group and the low risk group based on nomogram (P>0.05). Conclusion The radiomics nomogram based on T2WI can be used as a quantitative tool to predict synchronous liver metastases of rectal cancer.

An Improved Classification System for Brain Tumours Using Wavelet Transform and Neural Network / Un sistema de clasificación mejorado para los tumores cerebrales usando la transformada de ondeletas y la red neuronal

ABSTRACT This paper presents an improved classification system for brain tumours using wavelet transform and neural network. The anisotropic diffusion filter was used for image denoising, and the performance of the oriented rician noise reducing anisotropic diffusion (ORNRAD) filter was validated. The segmentation of the denoised image was carried out by fuzzy c-means clustering. The features were extracted using symlet and coiflet wavelet transforms, and the Levenberg-Marquardt algorithm based neural network was used to classify the magnetic resonance (MR) images. This classification technique of MR images was tested and analysed with existing methods, and its performance was found to be satisfactory with a classification accuracy of 93.24%. The developed system could assist physicians in classifying MR images for better decision-making.

RESUMEN Este artículo presenta un sistema de clasificación mejorado para los tumores de cerebro usando la transformada de ondeletas (transformada wavelet) y la red neuronal. El filtro de difusión anisotrópica fue utilizado para la eliminación del ruido de la imagen, y se validó el funcionamiento del filtro de difusión anisotrópica orientado a reducir el ruido riciano (ORNRAD, siglas en inglés). La segmentación de la imagen 'desruidizada ' (denoised) fue realizada mediante el agrupamiento difuso c-means fuzzy. Las características fueron extraídas usando las transformadas de ondeletas symlet y coiflet, y la red neuronal basada en el algoritmo de Levenberg-Marquardt fue utilizada para clasificar las imágenes de resonancia magnética (RM) imágenes. Esta técnica de clasificación de imágenes de RM fue probada y analizada con métodos existentes, y se halló que su rendimiento era satisfactorio con una precisión de clasificación de 93.24%. El sistema desarrollado podría ayudar a los médicos a clasificar imágenes de RM para una mejor toma de decisiones.

Does the Access Angle Change the Risk of Approach-Related Complications in Minimally Invasive Lateral Lumbar Interbody Fusion? An MRI Study

OBJECTIVE: To investigate the potential risk of approach-related complications at different access angles in minimally invasive lateral lumbar interbody fusion.METHODS: Eighty-six axial magnetic resonance images were obtained to analyze the risk of approach-related complications. The access corridor were simulated at different access angles and the potential risk of neurovascular structure injury was evaluated when the access corridor touching or overlapping the corresponding structures at each angle. Furthermore, the safe corridor length was measured when the corridor width was 18 and 22 mm.RESULTS: When access angle was 0°, the potential risk of ipsilateral nerve roots injury was 54.7% at L4–L5. When access angle was 45°, the potential risk of abdominal aorta, contralateral nerve roots or central canal injury at L4–L5 was 79.1%, 74.4%, and 30.2%, respectively. The length of the 18 mm-wide access corridor was largest at 0° and it could reach 44.5 mm at L3–L4 and 46.4 mm at L4–L5. While the length of the 22 mm-wide access corridor was 42.3 mm at L3–L4 and 44.1 mm at L4–L5 at 0°.CONCLUSION: Changes in the access angle would not only affect the ipsilateral neurovascular structures, but also might adversely influence the contralateral neural elements. It should be also noted to surgeons that alteration of the access angle changed the corridor length.

Does the Access Angle Change the Risk of Approach-Related Complications in Minimally Invasive Lateral Lumbar Interbody Fusion? An MRI Study

OBJECTIVE: To investigate the potential risk of approach-related complications at different access angles in minimally invasive lateral lumbar interbody fusion. METHODS: Eighty-six axial magnetic resonance images were obtained to analyze the risk of approach-related complications. The access corridor were simulated at different access angles and the potential risk of neurovascular structure injury was evaluated when the access corridor touching or overlapping the corresponding structures at each angle. Furthermore, the safe corridor length was measured when the corridor width was 18 and 22 mm. RESULTS: When access angle was 0°, the potential risk of ipsilateral nerve roots injury was 54.7% at L4–L5. When access angle was 45°, the potential risk of abdominal aorta, contralateral nerve roots or central canal injury at L4–L5 was 79.1%, 74.4%, and 30.2%, respectively. The length of the 18 mm-wide access corridor was largest at 0° and it could reach 44.5 mm at L3–L4 and 46.4 mm at L4–L5. While the length of the 22 mm-wide access corridor was 42.3 mm at L3–L4 and 44.1 mm at L4–L5 at 0°. CONCLUSION: Changes in the access angle would not only affect the ipsilateral neurovascular structures, but also might adversely influence the contralateral neural elements. It should be also noted to surgeons that alteration of the access angle changed the corridor length.

Presentación sincrónica de tumor epidermoides intracraneal y absceso cerebral: reporte de un caso / Synchronous presentation of intracranial epidermoid tumor and brain abscess: case report

Introducción: Un paciente con tumor epidermoides intracraneal extradural con presentación sincrónica con absceso cerebral, sin antecedentes de trauma craneal penetrante, no ha sido reportado con anterioridad en la revisión del tema realizada por los autores. Se presenta un caso con estas características y se exponen consideraciones sobre el diagnóstico y el tratamiento. Caso clínico: Paciente femenina, de 48 años de edad, con antecedentes de cefalea crónica y tumor craneal palpable en región frontal izquierda. Los estudios humorales fueron normales. La RNM craneal mostró dos imágenes en anillo yuxtapuestas, extra e intraaxial de forma respectiva. En la cirugía se encontró tumor perlado extradural sin evidencia a la inspección de tumor intradural, se comprobó en el examen histopatológico tumor epidermoides. En los controles imagenológicos posoperatorios se descubrió la persistencia de la lesión intraaxial, en anillo, frontal izquierda. Una segunda cirugía evidenció un absceso cerebral de ubicación subcortical y se efectuó la resección radical. La evolución fue favorable, sin secuelas después de cuatro meses de seguimiento. Conclusiones: Se reportó un caso infrecuente, donde se presentó de forma sincrónica un tumor epidermoides extradural frontal izquierdo y absceso cerebral frontal ipsilateral, sin relación de continuidad ni comunicación fistulosa demostrada en las neuroimágenes ni en la exploración quirúrgica.

Introduction: A patient with intracranial extradural epidermoid tumor with synchronous presentation with brain abscess and no history of penetrating head trauma, has not been previously reported in the revision of the subject made by the authors. A case with these characteristics is presented and also considerations about diagnosis and treatment. Case report: A 48-yearold female patient, with a history of chronic headache and cranial palpable tumor in left frontal region. Humoral studies were normal. Cranial MRI showed two juxtaposed, extra and intraaxial ring images. At surgery an extradural pearly tumor without evidence of intradural tumor on inspection was found, biopsy showed an epidermoid tumor. Persistence of intraaxial ring lesion in left frontal lobe was showed in postoperative imaging controls. A second surgery discovered a subcortical brain abscess and radical resection was done. Patient outcome has been without sequelae after four months of follow-up. Conclusions: An uncommon case where reported with extradural left frontal epidermoid tumor and ipsilateral frontal brain abscess synchronously presented, neither continuity nor fistulous communication were demonstrated on neuroimaging or surgical exploration.

Sensitivity of Pyramidal Signs in Patients with Cervical Spondylotic Myelopathy

STUDY DESIGN: This was a retrospective study. PURPOSE: The purpose of this study was to study the relationship between prevalence of pyramidal signs and the severity of cervical myelopathy. The study is focused on patients having increased signal intensity in T2-weighted magnetic resonance imaging. OVERVIEW OF LITERATURE: Cervical spondylotic myelopathy is the most common cause of spinal cord dysfunction in elderly population. It is the consequence of spondylotic changes leading to cervical cord injury with resulting clinical deficits. Diagnosis in such patients is made based on clinical and radiographic features. A patient must have both symptoms and signs consistent with cervical cord injury as well as radiographic evidence of damage to spondylotic cord. METHODS: Forty-six patients with complaint of cervical spondylotic myelopathy with increased signal intensity in T2-weighted magnetic resonance imaging were included in the study. The neurological finding of the patients was reviewed for the presence of pyramidal signs. The prevalence of each pyramidal sign was calculated and correlated to severity of cervical myelopathy. The motor function scores of the upper and lower extremities for cervical myelopathy set by the Japanese Orthopedic Association (motor Japanese Orthopaedic Association score, m-JOA) scores were used to assess severity of myelopathy. RESULTS: The most prevalent signs were hyperreflexia (89.1%), Hoffmann reflex (80.4%), Babiniski sign (56.5%), and ankle clonus (39.1%). Babiniski sign, ankle clonus, and Hoffmann reflex showed significant association with the lower m-JOA score. CONCLUSIONS: In patients with cervical myelopathy, hyperreflexia exhibited highest sensitivity whereas ankle clonus demonstrated lowest sensitivity. The prevalence of the pyramidal signs is correlated with increasing severity of myelopathy.

Classificação semi-automática da degeneração de discos intervertebrais em imagens imagens de ressonância magnética / Semi-automatic classification of disc degeneration intervertebraises in magnetic resonance images

Este trabalho descreve o desenvolvimento de um método que classifica de forma semi-automática a degeneração de discos intervertebrais lombares em imagens de ressonância magnética ponderadas em T2. O conjunto de imagens consiste de 210 discos extraídos de exames de 94 indivíduos (20 a 80 anos). A classificação é feita por uma rede neural do tipo perceptron multicamada com 6 entradas, 15 neurônios na camada intermediária e 1 saída. Os resultados obtidos mostraram uma taxa média de acerto de 81,42%, com erro padrão de 9,11%.

This article describes the development of a method that classifies semi-automatic degeneration of lumbar intervertebral discs in magnetic resonance T2-weighted images. The dataset consists of images of 210 discs obtained from94 individuals (20 to 80 year old). An artificial neural network of the multilayer perceptron with 6 inputs, 15 neuronsin the hidden layer and 1 output, was used to check the efficiency of this study. Obtained an average rate of sucess of81.42%, with a standard error of 9.11%.

Concordancia entre las Evaluaciones de la Articulación Temporomandibular Realizadas con los CDI/TTM y con Imágenes de Resonancia Magnética / Concordance between the Evaluations of the Temporomandibular Joint Performed with the RDC/TMD and with Images of Magnetic Resonance

Los Criterios Diagnósticos para la Investigación de los Trastornos Temporomandibulares (CDI/TTM) ofrecen un sistema estandarizado para evaluar la Disfunción Temporomandibular (DTM). Sin embargo, la validez del diagnóstico clínico obtenido con estos criterios al compararlo con el diagnóstico obtenido de las imágenes de Resonancia Magnética (RM) es controversial. El objetivo fue determinar la concordancia que existe entre la evaluación clínica realizada con los CDI/TTM e imágenes de RM de la articulación temporomandibular (ATM), de pacientes atendidos en la Clínica Integral del Adulto, de la Escuela de Odontología de la Universidad del Valle, en Cali, Colombia. Se evaluó clínicamente a 36 individuos, con edades comprendidas entre 18 y 60 años, utilizando los CDI/TTM y se les realizaron exámenes de RM. Las variables estudiadas fueron sexo, edad, signos y síntomas de la ATM, Posición Normal del Disco (PND), Desplazamiento Discal con Recaptura (DDCR) y Desplazamiento Discal Sin Recaptura (DDSR). Los datos obtenidos fueron sometidos a pruebas estadísticas para determinar el índice Kappa y características operativas de la prueba clínica. El Índice Kappa fue 0,53, con una concordancia entre las evaluaciones clínicas e imagenológicas moderada. De la población estudiada, 91,6% fue del sexo femenino, con 31 años como promedio de edad. El signo hallado con mayor frecuencia fue el ruido articular (77%) y el síntoma más frecuente fue el dolor facial (69%). La sensibilidad de los CDI/TTM para determinar la PND fue 0,52 y la especificidad 0,87; la sensibilidad para el DDCR fue 0,8780 y la especificidad 0,709; la sensibilidad para el DDSR fue 0,5714 y la especificidad 0,948. La DTM se presentó con mayor frecuencia en las mujeres, con edad promedio de 31 años. Los CDI/TTM pueden considerarse confiables, especialmente para el DDCR; sin embargo, tratamientos invasivos, permanentes o quirúrgicos, requerirían confirmación con un diagnóstico imagenológico para evitar falsos positivos.

The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) offer a standardized system to clinically evaluate the most common subtypes of Temporomandibular Disorders (TMD). However, the validity of the clinical diagnose obtained with these criteria when compared with the diagnose obtained from the images of Magnetic Resonance (MR) is controversial. The objective of this study was to determine the concordance existing between the clinical evaluation obtained from the RDC/TMD and that obtained from MR images of the temporomandibular joint (TMJ) of patients attending the Clínica Integral del Adulto ­ Clínica de ATM, of the Escuela de Odontología of the Universidad del Valle, Cali, Colombia. A population of 36 patients of both sexes, with ages between 18 and 60 years, were clinically evaluated with the RDC/TMD and MR. The variables considered were sex, age, signs and symptoms of the TMJ, Normal Disc Position (NDP), Disc Displacement with Reduction (DD-R) and Disc Displacement without Reduction (DD-NR). The data obtained were submitted to statistical tests to determine the Kappa Index and operative characteristics of the clinical evaluation. The Kappa Index obtained was 0.53, which shows that the concordance between the clinical and the imagenological evaluations is moderate. Of the total population studied, 91.6% were females, with 31 years as average age. The most frequent sign found was the joint sound (77%) and the most frequent symptom was facial pain (69%). The sensitivity of the RDC/TMD to determine NDP was 0.52 and the specificity 0.87; the sensitivity for the DD-R was 0.8780 and the specificity 0.709; the sensitivity for the DD-NR was 0.5714 and the specificity 0.948. The TMD were found most frequent in women, with average age of 31 years. The RDC/TMD can be considered reliable, especially for the DD-R; however, invasive, permanent or surgical treatments would require confirmation with imagenological diagnoses to avoid false positives.

Correspondência histológica de parâmetros de imagens de tensores de difusão / Correspondence of histological parameters from diffusion tensor images

INTRODUÇÃO: Imagens por tensores de difusão (diffusion tensor imaging - DTI) do cérebro são parte fundamental de exames de ressonância magnética (RM) na rotina clínica. Entretanto, não há informação científica suficiente para inferir a base histológica de parâmetros de imagens de DTI. Um dos achados frequentes nos exames de RM são as áreas de alteração de sinal na substância branca (AASSB). Neste estudo, analisamos imagens de RM post-mortem, em particular as AASSB, e seus correlatos histológicos e imuno-histoquímicos. OBJETIVOS: Descrever os parâmetros quantitativos de imagens de DTI imagens obtidas in cranio post-mortem, comparar com parâmetros de relaxometria e transferência de magnetização e avaliar seus correlatos histológicos nas AASSB e AHAN, utilizando técnicas de correspondência espacial ponto-a-ponto. MÉTODOS: Analisamos áreas distribuídas na substância branca de encéfalos de quatro sujeitos submetidos ao exame de RM post-mortem, aproximadamente 12,87 horas (±2,59). A RM foi realizada em sistema com campo de 3,0 T, sendo utilizadas imagens FLAIR; T2 multi-eco, DTI, Densidade de Prótons para cálculo da taxa de transferência de magnetização (magnetization transfer ratio - MTR). Foram delimitadas regiões de interesse (ROI) em 20 áreas contendo AASSB e 20 áreas homólogas aparentemente normais (AHAN). Para cada área, foram obtidos valores de anisotropia fracional (FA), coeficiente de difusão aparente (ADC), MTR e tempo T2. Os encéfalos foram seccionados em fatias de 0,4mm e fotografados em alta resolução. Estas imagens foram co-registradas tridimensionalmente com as imagens de RM, utilizando técnica semi-automatizada para correlação ponto-a-ponto. Os fragmentos analisados foram corados por hematoxilina-eosina (HE), Kluverx Barrera (KB), galocianina (GALL), anti-neurofilamento (anti-NF), antiproteína básica de mielina (anti-MBP) e anti-proteína ácida fibrilar glial (anti- GFAP). RESULTADOS: Os valores de FA foram 0,40 ±0,12 nas...

BACKGROUND: Diffusion tensor imaging (DTI) is part of magnetic resonance imaging (MRI) acquisition methods available in clinical exams. However, there are not enough scientific basis to infer the histological substract of DTI parameters. White matter hyperintensities (WMH) are frequent findings in clinical MRI routine. In the last years, scientific evidences show that these injuries are not just age-related benign changes, but they could be associated to pathological processes. In this study we analyzed post-mortem MRI DTI data, specifically investigating WMH, their histological and immunohistochemical correlates. OBJECTIVES : At present study, we aimed to analyze quantifiable DTI parameters - Fractional Anisotropy (FA) and Apparent Diffusion Coefficient (ADC) - relaxometry (RT2) and magnetization transfer ratio (MTR) in WMH compared and normal appearing white matter (NAWM) from images obtained postmortem and in situ, and assess their histological substracts at WMH and NAWM using a point-topoint correlation platform. METHODS : We analyzed 20 regions of interest (ROI) encompassing WMH and NAWM selected from four subjects using in situ post-mortem MRI data acquired in 3.0T MR system. The subjects were scanned with a post-mortem interval of approximately 12h54m (±2h36m). The MRI analysis included 3D T1, FLAIR; multi-echo T2, DTI, and proton density to calculate the rate of magnetization transfer (magnetization transfer ratio - MTR). In each ROI we obtained measures of FA, ADC, RT2 and MTR. Brain specimens were posteriorly fixed in celloidin, sectioned into 0.4mm slices and photographed in high resolution. These images were co-registered with three-dimensional MR images using semi-automated technique for correlation using a point-to-point method established in our group. WMH and NAWM ROIs from MRI were submitted to quantitative histological analysis based on optical density color-deconvolution technique. Histological section were stained in...

Análisis de espectros de resonancia magnética / Magnetic resonance spectrum analysis

Objetivo: Estudiar el comportamiento del uso de razones entre metabolitos y de la comparación de un volumen de interés con uno contralateral para determinar cuál de estas 2 técnicas es la más apropiada para obtener una relación del comportamiento metabólico de un espectro de resonancia magnética. Métodos: Fueron reclutados 10 voluntarios sanos, en los que fueron analizados el lóbulo parietal, el lóbulo temporal y los ganglios basales. Resultados: La cuantificación directa del espectro mostró un mayor coeficiente de variación dentro de los análisis realizados, lo cual justifica usar técnicas con referentes endógenos. El estudio de un volumen contralateral mostró ser una técnica con dispersión e índice de lateralidad altos. El uso de la creatina (Cr) como metabolito de control presentó un coeficiente de variación menor que la primera técnica evaluada. Los resultados hallados (ganglios basales: n-acetil-aspartato/Cr: 3 ± 6; colina/Cr: 2 ± 4. Lóbulo temporal: N-acetil-aspartato/Cr: 5 ± 5; colina/Cr: 8 ± 12. Lóbulo parietal: N-acetil-aspartato/Cr: 2,0 ± 0,6; colina/Cr: 0,9 ± 0,5) muestran valores similares a los encontrados en la literatura, con variaciones regionales considerables. Conclusiones: La técnica de cuantificación de la razón de los metabolitos con la Cr es la más adecuada para usar en el Instituto Nacional de Cancerología, por tener una dispersión menor y por arrojar valores cercanos a los reportados en la literatura en las diferentes regiones anatómicas estudiadas.

Objective: To study the performance in the use of metabolite ratios and the comparison of a contralateral volume of interest in order to determine which of these two techniques is most suitable for obtaining a ratio of the metabolite behaviour of a magnetic resonance spectrum. Methods: The parietal lobe, the temporal lobe, and basal ganglions were analysed in the 10 healthy volunteers included in the study. Results: The direct quantification of the spectra showed a wide coefficient of variation within the analyses performed, which justified using techniques with endogenous references. The study of a contralateral volume showed to be a technique with a high dispersion and laterality index. The use of creatinine (Cr) as a control metabolite had a lower coefficient of variation than the first technique evaluated. The results obtained (basal ganglions: N-acetyl-aspartate/Cr: 3 ± 6; choline/Cr: 2 ± 4. Temporal lobe: N-acetyl-aspartate/Cr: 5 ± 5; choline/Cr: 8 ± 12. Parietal Lobe: N-acetyl-aspartate/Cr: 2.0 ± 0.6; choline/Cr: 0.9 ± 0.5) showed similar values to those obtained in the literature, with considerable anatomical region variations. Conclusions: The technique that measures the ratio of the metabolites with Cr is the most suitable for use in the Instituto Nacional de Cancerología (National Oncology Institute), due to having a lower dispersion and producing results near those repo rted in the literature in the different anatomical regions studied.

The Change of Preoperative and Postoperaive Magnetic Resonance Imaging Findings in Lipofibromatous Hamartoma of the Median Nerve

Lipofibromatous hamartoma is a very uncommon, benign tumor that involves diffuse infiltration of peripheral nerves by normal-appearing fibrous and adipose tissues. We repost a rare case of secondary carpal tunnel syndrome due to a lipofibromatous hamartoma of the median nerve with preoperative and postoperative magnetic resonance images.

Oxygen-induced brain BOLD-fMRI signal change / 第二军医大学学报

Objective: To observe the signal changes of blood-oxygen-level-dependent functional MRI (BOLD-fMRI) in brain tissue after inhalation of oxygen. Methods: Fifteen volunteers, 9 males and 6 females, were included in the present experiment. The fMRI was conducted using 1.5T Singna Double-gradient Super Conducting Magnetic Resonance Imaging system (GE Inc). Bold-fMRI scanning was conducted using GRE-EPI sequence and data analysis was done using SPM2 software. Meanwhile, the BOLD-fMRI T2 signal changes after 15 s and 6 min inhalation of pure oxygen were observed and compared with those after inhaling normal air. Results: No obvious activation of BOLD-fMRI was observed in the whole brain after inhaling normal air. Fifteen seconds after inhaling pure oxygen, the signal changes in the whole brain mainly manifested as the signal decrease in the gray matter, with average signal change being (- 0.041 ± 0.31)% in the gray matter and about (0.056 ± 0.26)% in the white matter; the changes were significantly different from those of the normal air group (P<0.001). Six minutes after inhaling pure oxygen, signal changes in the whole brain mainly manifested as the signal increase in the white matter, with the average signal change being about (0.015±0.365)% in the gray matter and (0.14±0.278)% in the white matter; the changes were significantly different from those of the normal air group (P<0.001). Conclusion: Inhaling oxygen for different time periods can cause different BOLD signal changes in brain tissues. BOLD T2 signal in grey matter is decreased after short-time inhalation and is increased in white matter after long-time inhalation.

Epidermoid cyst: highlights on diagnosis and magnetic resonance imaging features / Cisto epidermóide: processo de diagnóstico e características das imagens por ressonância magnética

Purpose: Epidermoid and dermoid cysts are extremely rare developmental cysts of a benign nature, which may occur anywhere in the body, although about 7% are found in the head and neck. This article reports a clinical case of a patient who had an epidermoid cyst and its magnetic resonance imaging (MRI) features. Case report: This case discusses an epidermoid cyst in a 36-year-old woman complaining about speech difficulty. Clinical examination revealed an extensive swelling on the floor of the mouth. MRI findings showed a cystic homogenous lesion located underneath the mylohyoid muscle which was removed by surgery. Histological examination of the mass confirmed the diagnosis of an epidermoid cyst. Conclusion: We concluded that MRI was considered useful for a more accurate diagnosis prior to treatment.

Proposta: Cistos epidermóide e dermóide são cistos de desenvolvimento extremamente raros, de natureza benigna, que podem ocorrer em qualquer região do corpo e somente 7% são encontrados na região de cabeça e pescoço. Este artigo apresenta o caso clínico de uma paciente que possuía um cisto epidermóide juntamente com as características das imagens por ressonância magnética. Descrição do caso: Paciente do gênero feminino, 36 anos, apresentou-se com queixa de dificuldade de fonação e deglutição. O exame clínico intrabucal revelou uma extensa tumefação em soalho bucal. As imagens por ressonância magnética indicaram uma lesão de natureza cística, homogênea, de conteúdo sólido e localizada abaixo do músculo milohiódeo. A lesão foi enucleada e encaminhada para exame anatomopatológico, cujo diagnóstico foi compatível com cisto epidermóide. Conclusão: A imagem por ressonância magnética foi essencial para determinar as características da lesão de acordo com a sua localização anatômica.

Three Dimensional Automatic Surface Reconstruction Software / 대한의료정보학회지

OBJECTIVE: After drawing and stacking contour of structures, which are identifed in the serially sectioned images, three-dimensional (3D) images can be made by surface reconstruction. The 3D images can be selected and rotated in a real time. The purpose of this research is to compose software of automatic surface reconstruction for making 3D images. METHODS: Contours of 55 structures in the 613 magnetic resonance images of whole body were drawn to make segmented images. We composed automatic software for stacking contours of a structure, for converting the contours into polygons, and for connecting vertices of the neighboring polygons to fill gaps between polygons with triangular surfaces. The surface reconstruction software was excuted to make 3D images of 55 structures. RESULTS: Virtual dissection software, on which 3D images could be selected and rotated, was composed. CONCLUSION: For other research, this like program can be composed for automatic surface reconstruction; several kinds of commercial software can be used for manual or automatic surface reconstruction. Investigators might choose one of the methods in consideration of their only circumstances.

Methods of analysis based on the signal characteristics of fMRI / 国际生物医学工程杂志

The principles, traits, and proceedings of the data-driven methods including principal component analysis, independent component analysis and canonical analysis are summarized. And the aspects of the methods adapted to functional magnetic resonance images(fMRI) data are emphasized.

Serially Sectioned Images of the Whole Body - Sixth Report: Browsing Software of the Serially Sectioned Images for Learning Sectional Anatomy / 대한해부학회지

Sectional anatomy is the course to learn anatomical structures on the sectional planes of cadaver. The purpose of this research is to make browsing software of the serially sectioned images, which is useful not only to learn sectional anatomy but also to learn magnetic resonance (MR) images and computed tomography (CT) images. One-thousand seven-hundred two sets of corresponding anatomical, MR, CT, and segmented images (intervals 1 mm) were selected from the serially sectioned images (horizontal direction) of a Korean male cadaver's whole body. We composed browsing software (file size 377 MBytes) of the images, which involved the following functions: The anatomical, MR, CT, and segmented images, which were always corresponding, were displayed; one of four images could be enlarged; images of interesting levels could be displayed in a real time conveniently either using software buttons, scroll bar, image number or using computer keyboard; names of the 13 anatomical structures, which were already segmented, could be displayed. By using this software, medical students and doctors can figure out stereoscopic anatomical structures from the anatomical images to review anatomy; they can compare MR and CT images with corresponding anatomical images to easily recognize anatomical structures in the MR and CT images.

Cervical Spine Fracture Following Non-authorized Manipulation: A case report

We present a case of 5th cervical spine (C5) body fracture following cervical spine manipulation. The patient was an 18 year-old girl. She visited a non-authorized manipulation practitioner because of her shoulder pain. At that time she had no neck pain. During manipulation, the practitioner turned her neck suddenly with strong force, then she felt sudden neck pain. A fracture of the C5 body was identified in magnetic resonance images of the cervical spine. We should be aware of the risk of serious complications associated with chiropractic manipulation.