Correlation analysis between muscle CT measurement parameters, energy expenditure and risk of acute exacerbation in patients with stable chronic obstructive pulmonary disease / 中国医师进修杂志

Objective:To explore the correlation between muscle CT measurement parameters, energy expenditure and acute exacerbation in patients with stable chronic obstructive pulmonary disease (COPD).Methods:The clinical data of 146 patients with stable COPD from March 2020 to November 2021 in Lu′an Hospital Affiliated to Anhui Medical University (Lu′an People′s Hospital) were retrospectively analyzed. The clinical data were recorded; the lung function was measured by bronchodilator test. The cross-sectional area and CT value of the pectoral muscle were measured by reconstructed CT images of the mediastinum; the total energy consumption was calculated by Weir formula. Acute exacerbations within 3 and 12 months were recorded. Multivariate Logistic regression was used to analyze the independent risk factors for acute exacerbation in patients with stable COPD. The receiver operating characteristic (ROC) curve was used to analyze the efficacy of total energy expenditure, pectoral muscle cross-sectional area and pectoral muscle CT value for predicting acute exacerbation in patients with stable COPD.Results:Among 146 patients with stable COPD, 38 cases (26.03%) developed acute exacerbation within 3 months (acute exacerbation group), and 108 cases (73.97%) did not develop acute exacerbation (non-acute exacerbation group). The proportion of age<60 years old, rate of acute exacerbation within 12 months and rate of pulmonary function grading Ⅲ to Ⅳ in acute exacerbation group were significantly higher than those in non-acute exacerbation group: 71.05% (27/38) vs. 47.22% (51/108), 52.63% (20/38) vs. 30.56% (33/108) and 63.16% (24/38) vs. 37.96% (41/108), the total energy consumption, pectoral muscle cross-sectional area and pectoral muscle CT value were significantly lower than those in non-acute exacerbation group: (2 036.28 ± 163.13) J/d vs. (2 389.59 ± 204.71) J/d, (28.79 ± 3.45) cm 2 vs. (31.61 ± 4.56) cm 2 and (29.79 ± 3.06) HU vs. (34.52 ± 4.38) HU, and there were statistical differences ( P<0.05 or <0.01). Multivariate Logistic regression analysis result showed that age ≥60 years old, lower total energy expenditure, smaller pectoral muscle cross-sectional area and lower pectoral muscle CT value were independent risk factors for acute exacerbation in patients with stable COPD ( OR = 26.493, 1.015, 1.245 and 1.437; 95% CI 3.745 to 187.405, 1.008 to 1.022, 1.002 to 1.546 and 1.109 to 1.861; P<0.01 or <0.05). The ROC curve analysis result showed that combined prediction of the total energy consumption, pectoral muscle cross-sectional area and pectoral muscle CT value for acute exacerbation in patients with stable COPD had the largest area under the curve (0.962), with a sensitivity of 86.1%, a specificity of 80.8%, and the optimal cutoff values of 2 206.12 J/d, 32.39 cm 2 and 31.63 HU, respectively. Conclusions:The elderly age, smaller pectoral muscle cross-sectional area, lower pectoral muscle CT value and lower total energy expenditure are independent risk factors for acute exacerbation in patients with stable COPD. The combination of pectoral muscle cross-sectional area, pectoral muscle CT value and total energy expenditure has a good predictive effect on the risk of acute exacerbation in patients with stable COPD, and relevant indexes can be paid attention to in clinical treatment.

Clinical characteristics and CT findings of Pneumocystis Jirovecii pneumonia in 46 cases with hematological diseases / 中华血液学杂志

Objective: To summarize the original CT features of Pneumocystis Jirovecii pneumonia in patients with hematological diseases. Methods: A retrospective analysis was carried out in 46 patients with proven pneumocystis pneumonia (PJP) in the Hospital of Hematology, Chinese Academy of Medical Sciences between January 2014 and December 2021. All patients had multiple chests CT and related laboratory examinations, imaging typing were conducted based on the initial CT presentation, and the distinct imaging types were analyzed against the clinical data. Results: In the analysis, there were 46 patients with proven pathogenesis, 33 males, and 13 females, with a median age of 37.5 (2-65) years. The diagnosis was validated by bronchoalveolar lavage fluid (BALF) hexamine silver staining in 11 patients and clinically diagnosed in 35 cases. Of the 35 clinically diagnosed patients, 16 were diagnosed by alveolar lavage fluid macrogenomic sequencing (BALF-mNGS) and 19 by peripheral blood macrogenomic sequencing (PB-mNGS) . The initial chest CT presentation was categorized into 4 types, including ground glass (GGO) type in 25 cases (56.5%) , nodular type in 10 cases (21.7%) , fibrosis type in 4 cases (8.7%) , and mixed type in 5 cases (13.0%) . There was no substantial discrepancy in CT types among confirmed patients, BALF-mNGS diagnosed patients and PB-mNGS diagnosed patients (χ(2)=11.039, P=0.087) . The CT manifestations of confirmed patients and PB-mNGS diagnosed patients were primarily GGO type (67.6%, 73.7%) , while that of BALF-mNGS diagnosed patients were nodular type (37.5%) . Of the 46 patients, 63.0% (29/46) had lymphocytopenia in the peripheral blood, 25.6% (10/39) with positive serum G test, and 77.1% (27/35) with elevated serum lactate dehydrogenase (LDH) . There were no great discrepancies in the rates of lymphopenia in peripheral blood, positive G-test, and increased LDH among different CT types (all P>0.05) . Conclusion: The initial chest CT findings of PJP in patients with hematological diseases were relatively prevalent with multiple GGO in both lungs. Nodular and fibrosis types were also the initial imaging findings for PJP.

Evaluación multimodal del hematoma subdural crónico

Introducción: El hematoma subdural crónico es la complicación tardía más frecuente del trauma craneoencefálico. Su diagnóstico precoz y el tratamiento oportuno permiten la evolución favorable y curación de los pacientes. Objetivo: Sistematizar los diferentes ejes de clasificación del hematoma subdural crónico, que permitan la evaluación multimodal con una orientación más precisa de la técnica quirúrgica. Métodos: Se realizó una revisión bibliográfica en las principales bases de datos disponibles, centrada en las diferentes clasificaciones clínicas y radiológicas del hematoma subdural crónico y se seleccionaron 26 artículos. Se escogieron las principales clasificaciones y escalas y se aplicaron en 22 pacientes, obteniéndose resultados preliminares. Resultados: Las escalas de evaluación clínica de Bender, Marckwalder y la clasificación de Gordon Firing son las más conocidas, sin embargo, existen clasificaciones tomográficas que tienen en cuenta la densidad, la homogeneidad del hematoma que son de gran importancia en la selección de la técnica quirúrgica. La presencia de membranas y tabiques aparecen solo incluidas dentro de la valoración de la densidad del hematoma. Existen otras con valor predictivo que identifican aquellos factores relacionados con las recurrencias, desde antes de la cirugía, las mismas se consideran un factor de mal pronóstico para la evolución final de los pacientes con este tipo de hematomas. Conclusiones: La evaluación preoperatoria exige de la aplicación de múltiples escalas, la identificación y caracterización de las membranas es importante para personalizar la técnica quirúrgica, en busca de disminuir la morbilidad y mortalidad posoperatoria.

Introduction: Chronic subdural hematoma is the most frequent late complication of cranioencephalic trauma. The early diagnosis and correct treatment allow the recovery of patients. Objective: To systematize the different criteria of classification of chronic subdural hematoma that leads the multimodal evaluation for more effective selection of surgical technique. Methods: A review of literature about chronic subdural hematoma was done in the main database focused on different clinical and radiological classifications and 26 articles were selected. The main classifications and scales were chosen and applied to 22 patients, obtaining preliminary results. Results : Benders, Marckwalder and Gordon Firing scales are the most common, nevertheless there are tomographic classifications that include density, homogeneity of hematoma that are of great importance in the selection of the surgical technique. The presence of membranes and septum are only included in the evaluation of hematoma density. There are some others with predictive value that identify those factors related to recurrences before surgery that are considered a bad prognosis to the final evolution of these patients with this type of hematoma. Conclusions: The previous evaluation to surgery requires the use of different scales, the identification and characterization of membranes are important to select the optimum surgical technique to decrease morbidity and mortality after surgery.

A new classification of atlas fracture based on CT reconstruction and its clinical significance / 中华骨科杂志

Objective:To investigate the clinical significance of a new classification system for atlas fractures based on pre- and post-treatment CT features, with a focus on diagnosis and treatment.Methods:A retrospective analysis was conducted on 75 cases of cervical vertebra fractures treated at the Sixth Hospital of Ningbo City between January 2015 and December 2020. The study included 44 males and 31 females, with an average age of 53.3±13.0 years (range: 27-81 years). The fractures were classified according to the Landells classification, resulting in 12 cases of type I, 13 cases of type II, 33 cases of type III, 9 cases that were difficult to classify due to fracture lines located at anatomical junctions, and 8 cases that could not be classified using the Landells classification due to diverse injury mechanisms. To establish a new preliminary classification for cervical vertebra fractures, the researchers considered whether the fracture line in the CT images involved the facet joint surface of the atlas, the impact on bilateral half-rings, and the displacement distance of the fracture ends. Five spinal surgeons were randomly selected to classify the CT images of the 75 patients using the new classification method. After one month, the imaging data of the 75 cases of cervical vertebra fractures were randomized and reclassified to assess the reliability and repeatability of the classification.Results:The new cervical vertebra fracture classification method comprised three types based on whether the fracture line involved the facet joint surface of the atlas: type A (no involvement of the facet joint surface of the atlas), type B (involvement of one side of the facet joint surface with intact contralateral half-ring), and type C (involvement of one side of the facet joint surface with fractured contralateral half-ring). Additionally, based on the maximum displacement distance between the fracture ends (>4 mm), six subtypes were identified: subtype 1 (≤4 mm displacement) and subtype 2 (>4 mm displacement). Consequently, the subtypes were classified as A1, A2, B1, B2, C1, and C2. According to the new classification method, the 75 patients included 17 cases of A1, 12 cases of A2, 7 cases of B1, 13 cases of B2, 12 cases of C1, and 14 cases of C2. The classification demonstrated excellent consistency, as assessed by the five doctors, with Kappa values of 0.85 and 0.91 for reliability and repeatability, respectively. At the final follow-up, all conservatively treated patients achieved bone healing, while four surgically treated patients experienced non-union of the fracture ends but exhibited good fusion between the atlas and axis. The remaining surgically treated patients achieved bony union without complications such as loosening or fracture of internal fixation.Conclusion:The new cervical vertebra fracture classification method, based on CT imaging features, comprehensively covers common clinical cases of cervical vertebra fractures and demonstrates excellent consistency. It provides valuable clinical guidance for the diagnosis and treatment of cervical vertebra fractures.

Diagnostic value of thin-layer three-dimensional reconstruction technology combined with personalized scanning for benign and malignant solid solitary pulmonary nodules / 中国基层医药

Objective:To investigate the diagnostic value of thin-layer three-dimensional reconstruction technology combined with personalized scanning for benign and malignant solid solitary pulmonary nodules.Methods:The clinical data of 140 patients with solid solitary pulmonary nodules admitted to Jiangshan People's Hospital form January 2020 to July 2021 were retrospectively analyzed. These patients consisted of 40 patients with benign solid solitary pulmonary nodules (benign group) and 100 patients with malignant solid solitary pulmonary nodules (malignant group). All patients underwent thin-layer three-dimensional reconstruction combined with personalized scanning. The pulmonary nodule signs achieved by thin-layer three-dimensional reconstruction combined with personalized scanning and the diagnostic performance of the combined technology were compared between benign and malignant groups.Results:The proportions of patients with lung cavity sign, lobular sign, vascular convergence sign, vacuole sign, emphysema distribution sign, split pleura sign, and distal perforating vascular sign in the malignant group were 11.0%, 81.0%, 77.0%, 49.0%, 6.0%, 10.0% and 31.0%, respectively, and they were 42.5%, 62.5%, 55.0%, 27.5%, 20.0%, 32.5%, and 5.0%, respectively in the benign group ( χ2 = 15.80, 5.00, 5.66, 4.55, 4.76, 8.96, 9.33, all P < 0.05). The most sensitive sign was lobular sign, which had the highest efficiency, up to 82.0%, in differentiating benign and malignant pulmonary nodules. Conclusion:Lung cavity sign, lobular sign, vascular convergence sign, vacuole sign, emphysema distribution sign, split pleura sign, and distal perforating vascular sign differ greatly between patients with benign and malignant solid solitary pulmonary nodules. Lobular sign has the highest sensitivity in differentiating benign and malignant solid solitary pulmonary nodules. Thin-layer three-dimensional reconstruction combined with personalized scanning has a diagnostic value for benign and malignant solid solitary pulmonary nodules.

Multi-slice spiral CT manifestations of perivascular epithelioid cell tumors / 中国基层医药

Objective:To investigate CT manifestations of perivascular epithelioid cell tumors.Methods:The multi-slice spiral CT manifestations in 11 patients with perivascular epithelioid cell tumors which were pathologically confirmed in the First Affiliated Hospital of Shantou University Medical College between October 2012 and August 2021 were retrospectively analyzed.Results:Perivascular epithelioid cell tumors were located in the kidney of eight patients, in the right lobe of the liver of two patients, and in the descending colon of one patient. The largest tumor, approximately 20.0 cm × 26.0 cm × 11.0 cm, was located in the kidney. The smallest tumor, 2.4 cm × 2.6 cm × 3.4 cm, was located in the colon. CT plain scans showed uniform density without bleeding, calcification, or fat in two patients, and non-uniform density with fatty change in two patients. Contrast-enhanced CT images showed non-uniform enhancement in the arterial phase in 10 patients and uniform enhancement in one patient. Contrast-enhanced CT images showed decreased degrees of enhancement of the lesions in 11 patients from the portal venous phase to the delayed phase and dilated and tortuous vascular shadows in 11 patients.Conclusion:The multi-slice spiral CT manifestations of perivascular epithelioid cell tumors are characteristic and the multi-slice spiral CT is of value for the diagnosis of perivascular epithelioid cell tumors.

Diagnostic value and clinical significance of MRI combined with MSCT in ischiofemroal impingement syndrome / 中国医师杂志

Objective:To explore the diagnostic value and clinical significance of total volume of quadratus femoris muscle (TQFMV), ischial angle, femoral neck angle (FNV) measured by magnetic resonance imaging (MRI) combined with eccentric distance and lesser trochanter height measured by multi-slice spiral CT (MSCT) in the diagnosis of ischiofemoral impingement (IFI) syndrome.Methods:A total of 82 patients with IFI in Beijing Huairou Hospital from October 2017 to July 2020 were selected as the observation group. In addition, 82 healthy patients who underwent MRI and MSCT were collected as the control group. The general data, MRI and MSCT parameters of the two groups were compared, and IFI influencing factors were analyzed by logistic regression. The correlation between MRI and MSCT parameters and clinical manifestations and the correlation between MRI and MSCT parameters were analyzed. The receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value of MRI and MSCT parameters for IFI.Results:There were statistically significant difference between the two groups of gender, age, MRI parameters (TQFMV, ischial angle, FNV), and MSCT parameters (eccentricity, lesser trochanter height) (all P<0.05). Logistic regression analysis showed that gender, age, MRI parameters (TQFMV, ischial angle, FNV), MSCT parameters (eccentricity, lesser trochanter height ) were all influencing factors of IFI (all P<0.05). MRI parameters (TQFMV, ischial angle, FNV), MSCT parameters (eccentricity, lesser trochanter height) were all related to quadratus femoris muscle (QFM) edema, fat infiltration and pain degree in IFI patients (all P<0.05). The MRI parameter TQFMV of IFI patients was positively correlated with the MSCT parameter eccentricity and lesser trochanter height, while the ischial angle and FNV were negatively correlated with the MSCT parameter eccentricity and lesser trochanter height (all P<0.05). The AUC of MRI parameters (TQFMV, ischial angle, FNV) and MSCT parameters (eccentricity, lesser trochanter height) in the diagnosis of IFI were high, especially the highest in combined diagnosis, reaching 0.859. Conclusions:MRI parameters TQFMV, ischial angle, FNV and MSCT parameters, eccentricity and lesser trochanter height are related to the clinical manifestations of IFI patients. Combined detection of them can improve the diagnostic value of IFI and avoid missed diagnosis and misdiagnosis.

CT parameter changes and imaging analysis of each cerebral lobe in patients with monophasic depression / 中国基层医药

Objective:To analyze the imaging changes of patients with monophasic depression based on the changes in CT parameters of each cerebral lobe.Methods:A total of 100 patients with monophasic depression who received treatment in Department of Radiology, Shaoxing 7 th People's Hospital between June 2019 and June 2021 were included in the observation group. An additional 100 healthy individuals who concurrently received physical examination were included in the control group. CT scan of the brain was performed in all participants. CT value of each cerebral lobe was compared between the two groups. Results:CT values of the left frontal lobe and left temporal lobe in the observation group were (40.88 ± 2.01) HU and (40.21 ± 3.01) HU, respectively, which were significantly lower than those in the control group ( tleft frontal lobe = 2.94, P = 0.004; tleft temporal lobe = 3.29, P = 0.001). CT values of the right frontal lobe and right temporal lobe in the observation group were (40.09 ± 2.52) HU and (44.93 ± 3.03) HU, respectively. There were no significant differences in CT values of the right frontal lobe and right temporal lobe between the two groups ( tright frontal lobe = 1.89, P = 0.060; tright temporal lobe = 1.89, P = 0.060). There were no significant differences in CT values of the left and right occipital lobes and the left and right parietal lobes between the two groups (all P > 0.05). One-way analysis of variance revealed that the CT values of the left and right frontal lobes were negatively correlated with age (-0.441, -0.211) and course of disease (-0.445, -0.191) (both P < 0.05); the CT values of the left and right frontal lobes were not significantly correlated with 24-item Hamilton Depression Rating Scale score and the number of attacks (all P > 0.05). The CT values of the left and right temporal lobes (-0.207, -0.213), the left and right occipital lobes (-0.185, -0.195) and the left and right parietal lobes (-0.185, -0.180) were negatively correlated with age (all P < 0.05). The CT values of the left and right temporal lobes, the left and right occipital lobes, and the left and right parietal lobes were not significantly correlated with course of disease, 24-item Hamilton Depression Rating Scale score, and the number of attacks (all P > 0.05). Conclusion:The left and right frontal lobe and the left temporal lobe are atrophic in patients with monophasic depression. The degree of atrophy is closely related to the course of disease. Therefore, these findings can be used as a reference for imaging diagnosis of degenerative diseases of the central nervous system.

Comparison of diagnostic value of ultrasound and multi-slice spiral CT in wrist joint lesions of rheumatoid arthritis / 中国医师进修杂志

Objective:To investigate the diagnostic value and imaging characteristics of ultrasound and multi-slice spiral CT in rheumatoid arthritis (RA) wrist joint lesions.Methods:The clinical data of 54 cases of RA wrist arthropathy in Jianhu Hospital Affiliated to Nantong University from December 2018 to April 2020 were analyzed. All the patients were examined by ultrasound and multi-slice spiral CT. The imaging characteristics of ultrasound and multi-slice spiral CT were analyzed, and the detection rates of synovitis, joint effusion, tenosynovitis, bone erosion and wrist joint lesions were calculated.Results:A total of 1 188 joints were examined in 54 patients with RA, including 108 wrist joints, 540 metacarpophalangeal joints and 540 proximal interphalangeal joints. There was no significant difference in the detection rate of wrist joint synovitis, joint effusion and tenosynovitis between ultrasound and CT ( P>0.05). The wrist joint lesions detection rates of ultrasound and CT were 97.2%(105/108) and 46.3% (50/108), the difference was statistically significant ( χ2 = 36.52, P<0.05). Ultrasound image features: synovitis ultrasound image showed hypoechoic joint cavity, not by joint displacement or compression image, color Doppler flow imaging (CDFI) examination could see blood flow signal;joint effusion in ultrasound image of joint effusion was strip, strip-shaped, non-uniform distribution, image was affected by joint displacement or compression, CDFI examination had no blood flow signal; bone erosion ultrasound image showed bone cortical continuous interruption or "crater" "insect erosion" like defects. CT imaging features: wrist joint space narrow, osteoporosis, some patients with scaphoid, distal radius visible bone erosion. Conclusions:The detection rate of wrist synovitis, joint effusion and tenosynovitis by ultrasound and multi-row spiral CT are similar. The multi-row spiral CT examination have a slight advantage in evaluating the joint space and bone changes. The sensitivity of wrist bone erosion and wrist joint lesions are higher than those of multi-row spiral CT, which can guide the early clinical diagnosis and treatment of RA.

Clinical study of venous phase CT value in predicting central group lymph node metastasis of papillary thyroid carcinoma / 国际肿瘤学杂志

Objective:To investigate the clinical value of imaging features of primary lesions combined with venous phase CT value in predicting central group lymph node (LN) metastasis in patients with papillary thyroid carcinoma (PTC) .Methods:Clinical data of 170 PTC patients who underwent central group LN dissection in the First People's Hospital of Handan City of Hebei Province from January 2017 to June 2020 were retrospectively analyzed. All patients were divided into different groups according to whether central group LN metastasis or not, and there were 89 patients with central group LN metastasis and 81 patients without central group LN metastasis. The CT value and imaging features of primary lesions in different periods were analyzed, and the imaging features of primary lesions combined with venous phase CT values to predict the central group LN metastasis were evaluated by the receiver operating characteristic (ROC) curve.Results:There were no statistically significant differences in CT value in plain scan phase and CT value, net increased CT value, standardized CT value in arterial phase between patients with and without central group LN metastasis (all P>0.05) . The CT value, net increased CT value and standardized CT value in venous phase of patients with central group LN metastasis were (113.84±22.95) HU, (59.05±12.10) HU and 0.72±0.14 respectively, which were significantly higher than those of patients without central group LN metastasis [ (103.99±17.67) HU, (51.29±14.45) HU and 0.59±0.10] ( t=3.26, P<0.001; t=3.81, P<0.001; t=3.67, P<0.001) . ROC curve analysis showed that the area under the curve for diagnosing central group LN metastasis of PTC patients was 0.75, 0.70 and 0.76 when the cut-off values of CT value, net increased CT value and standardized CT value in venous phase were 115.78 HU, 62.37 HU and 0.75 respectively. There were statistically significant differences in the diameter of primary focus and the contact area of thyroid capsule between patients with and without central group LN metastasis ( Z=-2.34, P=0.019; Z=-2.08, P=0.037) . There were no statistically significant differences between calcification and primary lesion location (both P>0.05) . Lesion diameter >2 cm (87.73%) and capsule contact range ≥1/2 (92.17%) had the highest specificity in predicting central group LN metastasis. The imaging features of primary lesion combined with standardized CT value in venous phase was in good agreement with histopathological diagnosis results in predicting central group LN metastasis (Kappa=0.475) , and the sensitivity and specificity were 73.12% and 82.75% respectively. Conclusion:The imaging features of the primary lesion combined with CT value in venous phase have a good clinical value in predicting central group LN metastasis in PTC patients. Patients with primary lesion diameter >2 cm, capsule contact range ≥1/2 and the standardized CT value in venous phase >0.75 are more likely to have central group LN metastasis.

Caracterización tomográfica de las membranas en pacientes con hematoma subdural crónico

Introducción: El hematoma subdural crónico es un hematoma encapsulado por dos membranas interna y externa. Existen diferentes clasificaciones imagenológicas que incluyen las características de estas lesiones, pero la presencia de las membranas y sus características es un aspecto poco descrito. Objetivo: Describir las características tomográficas de las membranas de los hematomas subdurales crónicos. Métodos: Se realizó un estudio descriptivo en el Servicio de Neurocirugía en conjunto con el Servicio de Imagenología, del Hospital Universitario Manuel Ascunce Domenech durante el año 2021. Se incluyeron 20 pacientes adultos que fueron operados con el diagnóstico de hematoma subdural crónico. Las membranas se caracterizaron de acuerdo con su densidad, grosor, número de capas, morfología y extensión. Resultados: Predominaron los pacientes de más de 65 años del sexo masculino, con hematomas unilaterales más frecuentes del lado izquierdo. El volumen promedio fue de 150 ml y el diámetro fue de 3 cm. Fueron más frecuentes las membranas finas, hiperdensas, incompletas, de una sola capa y la morfología fue variable. Conclusiones: Las membranas que conforman el hematoma subdural crónico pueden observarse en la tomografía axial computarizada. Se han encontrado diferentes tipos de membranas de acuerdo con su densidad, grosor, morfología, extensión y presencia de tabiques. La presencia de una membrana gruesa o fina con tabiques, puede tener indicación de una craneotomía que permita la resección cuidadosa de la membrana parietal y la apertura suficiente de la visceral para facilitar la re expansión cerebral y disminuir la incidencia de recolecciones.

Introduction: Chronic subdural hematoma is a hematoma encapsulated by two internal and external membranes. There are different imaging classifications that include the characteristics of these lesions, but the presence of the membranes and their characteristics is a little described aspect. Objective: To describe the tomographic characteristics of the membranes of chronic subdural hematomas. Methods: A descriptive study was carried out in the Neurosurgery service in conjunction with the Imaging service of the Manuel Ascunce Domenech University Hospital during the year 2021. 20 adult patients who underwent surgery with the diagnosis of chronic subdural hematoma were included. The membranes were characterized according to their density, thickness, number of layers, morphology and extension. Results: Male patients over 65 years of age predominated, with more frequent unilateral hematomas on the left side. The average volume was 150 ml and the diameter was 3 cm. Thin, hyperdense, incomplete, single-layer membranes were more frequent, and the morphology was variable. Conclusions: The membranes that make up the chronic subdural hematoma can be seen on computerized axial tomography. Different types of membranes have been found according to their density, thickness, morphology, extension and presence of septa. The presence of a thick or thin membrane with septa may indicate a craniotomy that allows careful resection of the parietal membrane and sufficient opening of the visceral membrane to facilitate brain re-expansion and reduce the incidence of recollections.

Feasibility study of percutaneous placement of lumbar cortical bone trajectory screws based on CT data / 中华骨科杂志

Objective:To simulate the placement of percutaneous cortical bone trajectory (CBT) screws on reconstructed CT images and three-dimensional lumbar model and to measure the morphometric parameters for guiding the placement of percutaneous CBT screws.Methods:The CT images of 100 adult patients with lumbar spine diseases were studied. The CT images were reconstructed using Mimics software. Taking the projection point on the lamina at the junction of the inner and lower edge of the smallest coronal section of lumbar pedicle as the entry point, the cephalad angle, lateral angle, maximum screw length, maximum screw diameter, distance between trajectory and spinous process were measured. At the same time, the relationship between the trajectory and spinous process was observed by using the reconstructed three-dimensional image.Results:The lateral angle of the trajectory from L 1 to L 5 were 9.3° (8.9°, 9.8°), 9.6° (8.9°, 9.8°), 10.4° (9.5°, 11.3°), 11.81°±1.24° and 13.6° (12.5°, 14.5°), respectively. The cephalad angle from L 1 to L 5 were 26.6° (26.0°, 27.0°), 26.2° (25.7°, 26.5°), 26.9° (26.5°, 27.4°), 25.94°±0.92° and 24.3° (22.7°, 25.4°), respectively. Significant statistic differences were found among all levels in the cephalad angles and lateral angles. The mean diameters of the trajectory from L 1 to L 5 were 5.65±0.49 mm, 6.38±0.60 mm, 6.91±0.67 mm, 7.42±0.76 mm and 8.33 (7.59, 9.01) mm, respectively. Except L 1 and L 5, there were significant differences among all levels in the maximum screw diameters. The mean length of the trajectory from L 1 to L 5 were 36.4 (35.4, 37.0) mm, 36.7 (35.8, 37.3) mm, 37.6 (37.1, 38.1) mm, 37.8 (37.3, 38.1) mm and 36.2 (35.2, 36.9) mm, respectively, and there were also significant differences among all levels. The ration in superior endplate for each segment were 41.08% (34.36%, 45.60%), 37.94% (32.97%, 43.63%), 40.18% (34.56%, 44.49%), 38.61% (34.80%, 46.24%) and 40.9% (35.32%, 46.02%), respectively and statistical differences were significant between L 1 and L 2 and L 2 and L 5. The mean distance between the trajectory and the spinous process from L 1 to L 5 were 7.27±1.23 mm, 7.19 (5.97, 8.28) mm, 7.32 (6.01, 8.28) mm, 7.31±1.36 mm and 7.45 (6.32, 8.23) mm, respectively. In the sagittal CT image, the tip of the trajectory located near the posterior two-fifths of the superior end plate, and the extended line of the trajectory located at the inferior edge of spinous process. In the three-dimensional reconstruction model, no obstruction was found between the simulated screws and the spinous process. Conclusion:Lumbar CBT screw can be implanted percutaneously, and spinous process will not hinder the implantation process. Spinous process and upper endplate can be used as a sign to guide the percutaneous CBT screw implantation. Digital analog screw placement can offer a useful reference for the clinical application of percutaneous cortical bone trajectory screw.

Long-term prognosis evaluation value of normal coronary computed tomography angiography in patients with suspected coronary heart disease / 中国医师进修杂志

Objective:To explore the long-term prognosis evaluation value and risk factors of normal coronary computed tomography angiography (CCTA) in patients with suspected coronary heart disease (CHD).Methods:The clinical data of 332 patients with suspected CAD from June 2006 to July 2017 in the First Affiliated Hospital of Dalian Medical University were retrospectively analyzed. All patients received more than 2 times of CCTA examination, and the baseline CCTA was normal. Patients were followed up for at least 4 years, and the endpoints were coronary neo-plaque on CCTA or cardiovascular events.Results:Among 332 patients, the interval time between baseline and follow-up CCTA and clinical follow-up time were (5.6 ± 0.5) and (9.8 ± 0.6) years, 304 patients had normal baseline and follow-up CCTA (group Ⅰ); 28 patients had normal baseline CCTA while abnormal follow-up (group Ⅱ), the patient found coronary neo-plaque, and the incidence of coronary neo-plaque was 8.4% (28/332). Two patients (0.6%, 2/332) suffered from cardiovascular events, all of whom were in group Ⅱ. In group Ⅱ, a total of 34 coronary neo-plaques were found on follow-up CCTA. Multivariate Logistic regression analysis results showed that smoking, hypertension and hyperlipidemia were the independent risk factors of normal baseline while follow-up CCTA with neo-plaque in patients with suspected CAD ( β = 0.84, 0.83 and 0.84; OR = 2.37, 2.32 and 2.33; P<0.01). Conclusions:The suspected CAD patients with normal baseline CCTA have a good long-term prognosis. However, the patients who have risk factors such as smoking, hypertension and hyperlipidemia should be taken seriously, especially the patients who have normal baseline while follow-up CCTA with neo-plaque.

Encondroma: a propósito de un caso / Enchondroma: a case report

RESUMEN Fundamento: los tumores óseos son lesiones frecuentes, cada tipo histológico tiene patrones típicos que los identifican. Sin embargo, en ocasiones se pueden presentar de forma atípica. Objetivo: conocer el caso de una paciente con encondroma en la región proximal de la tibia derecha. Presentación del caso: mujer de 74 años de edad, blanca con antecedentes de hipertensión arterial y asma bronquial, la cual acude a la consulta de Ortopedia y Traumatología por dolor a nivel de la rodilla derecha que aumenta con la actividad física y se acompaña de limitación funcional y crepitación articular. La tomografía axial computarizada mostró imagen osteoblástica a nivel de la meseta tibial derecha sin ruptura de la cortical. Además se evidenció múltiples quistes subcondrales de aspecto degenerativo, presencia de osteofitos tibiales, femorales ipsi y contralateral, espacio femoro-rotuliano muy disminuido asociado a esclerosis del cóndilo femoral. Con los elementos descritos se decidió llevar la paciente al quirófano, para tratamiento de tipo quirúrgico. Se realizó exéresis de la tumoración, la que fue enviada al departamento de anatomía patológica para estudio histológico que confirmó el diagnóstico. La zona de hueso extraída se llenó con cemento quirúrgico. Conclusiones: el encondroma es un tumor benigno de origen cartilaginoso, su presencia por encima de los 40 años de edad es ocasional y constituye el principal diagnóstico diferencial del condrosarcoma de bajo grado histológico. Debido a lo infrecuente de esta afección fuera de su rango de edades, es necesaria la biopsia para confirmar el diagnóstico.

ABSTRACT Background: bone tumors are common lesions, there are specific features related to each histological type, but unusual and atypical presentations do occur. Objetive: to show the case of a patient with an enchondroma in the proximal right tibial plateau. Case report: a 74 year old white woman, who had had previous personal history of hypertension and asthma is taken to the Orthopaedic and Traumatology outpatient department complaining of right knee pain which gets worse with physical activity associated to limited range of motion and articular crepitus. CT scan showed an osteoblastic lesion in the proximal upper right tibial plateau without cortical breaking. On the other hand, multiple subchondral degenerative cysts were found in the knee joint as well as osteophytes, sclerosis and joint space narrowing. Taken into account the entire previous patient' features, surgery was performed and consist of tumor resection with bone cement filled. The specimen was send to the pathology department showing enchondroma. Conclusions: enchondroma is a benign cartilaginous bone tumor unfrequently found over 40 years of age, the main differential diagnosis is low grade chondrosarcoma. Because of the infrequent presentation of this case in regards to age, surgery was warranted to confirm diagnosis.

Appearance of COVID-19 pneumonia on 1.5 T TrueFISP MRI / Aspectos da pneumonia por COVID-19 na ressonância magnética 1.5 T TrueFISP

Abstract Objective: To evaluate the performance of 1.5 T true fast imaging with steady state precession (TrueFISP) magnetic resonance imaging (MRI) sequences for the detection and characterization of pulmonary abnormalities caused by coronavirus disease 2019 (COVID-19). Materials and Methods: In this retrospective single-center study, computed tomography (CT) and MRI scans of 20 patients with COVID-19 pneumonia were evaluated with regard to the distribution, opacity, and appearance of pulmonary lesions, as well as bronchial changes, pleural effusion, and thoracic lymphadenopathy. McNemar's test was used in order to compare the COVID-19-associated alterations seen on CT with those seen on MRI. Results: Ground-glass opacities were better visualized on CT than on MRI (p = 0.031). We found no statistically significant differences between CT and MRI regarding the visualization/characterization of the following: consolidations; interlobular/intralobular septal thickening; the distribution or appearance of pulmonary abnormalities; bronchial pathologies; pleural effusion; and thoracic lymphadenopathy. Conclusion: Pulmonary abnormalities caused by COVID-19 pneumonia can be detected on TrueFISP MRI sequences and correspond to the patterns known from CT. Especially during the current pandemic, the portions of the lungs imaged on cardiac or abdominal MRI should be carefully evaluated to promote the identification and isolation of unexpected cases of COVID-19, thereby curbing further spread of the disease.

Resumo Objetivo: Avaliar o desempenho da ressonância magnética (RM) de 1,5 T true fast imaging with steady state precession (TrueFISP) para detecção e caracterização de anormalidades pulmonares causadas por doença do coronavírus 2019 (COVID-19). Materiais e Métodos: Neste estudo retrospectivo unicêntrico, imagens de tomografia computadorizada (TC) e RM de 20 pacientes com pneumonia COVID-19 foram avaliadas em relação a distribuição, opacidade e forma das lesões pulmonares, anormalidades brônquicas, derrame pleural e linfadenopatia torácica. O teste de McNemar foi usado para comparar os achados associados à COVID-19 na TC e na RM. Resultados: As opacidades em vidro fosco foram mais bem visualizadas na TC do que na RM (p = 0,031). Não foram encontradas diferenças estatisticamente significantes entre TC e RM em relação aos outros aspectos, ou seja, visualização de consolidações e espessamento septal interlobular/intralobular, distribuição ou forma de anormalidades pulmonares, doenças brônquicas, derrame pleural ou linfadenopatia torácica. Conclusão: As anomalias pulmonares causadas pela pneumonia por COVID-19 podem ser detectadas nas sequências TrueFISP e correspondem aos padrões conhecidos da TC. Especialmente em face da pandemia atual, as porções de imagem dos pulmões na RM cardíaca ou abdominal devem ser cuidadosamente avaliadas para apoiar a identificação e o isolamento de casos inesperados de COVID-19 e, assim, conter a disseminação.

Diagnostic performance of multislice computed tomography to detect diaphragmatic injuries in hemodynamically stable patients. Preliminary results / Rendimiento diagnóstico de la tomografía computarizada multidetector para la identificación de heridas diafragmáticas en pacientes hemodinámicamente estables. Resultados preliminares

Abstract Introduction: Diaphragmatic injuries are a common finding in patients with penetrating thoracoabdominal trauma. Their diagnosis requires exploration through open or laparoscopic surgery. However, multislice computed tomography (MSCT) emerges as a useful noninvasive tool for this purpose. Objective: To determine the diagnostic performance of MSCT for detecting diaphragmatic injuries in hemodynamically stable patients with penetrating thoracoabdominal trauma. Materials and methods: Prospective study conducted on 119 patients treated at the Hospital Universitario del Valle, Cali, Colombia, between March 2012 and June 2015. In order to evaluate the diagnostic performance of MSCT, the results obtained through this test were compared with those reported in the reference test (open surgery). Two readings of the imaging studies were performed by 2 radiologists. Intra- and interobserver agreement on the MSCT readings were analyzed using the Fleiss' Kappa coefficient. Results: MSCT had sensitivity and specificity of 94.4% and 46.8%, respectively. Its positive (PPV) and negative (NPV) predictive values were 44.7% and 94.8%, respectively. The positive likelihood ratio (LR+) was 1.7765, and the negative likelihood ratio (LR-) was 0.1186. Regarding interobserver agreement, Fleiss' Kappa coefficient between the first reading of both radiologists was 0.4425. Conclusions: MSCT specificity for diagnosing diaphragmatic injuries found in this study differs considerably from that reported in the literature. Considering the sensitivity, PPV and LR- values obtained in the present study, MSCT could be an important tool for the management of these patients since conservative treatment may be used in patients whose diaphragmatic injuries are not detected with this type of scan.

Resumen Introducción. Las heridas diafragmáticas son un hallazgo común en pacientes con trauma toracoabdominal penetrante. Su diagnóstico requiere exploración mediante cirugía abierta o laparoscópica. Sin embargo, la tomografía computarizada multidetector (TCMD) surge como una herramienta no invasiva útil para este propósito. Objetivo. Determinar el rendimiento diagnóstico de la TCMD en la identificación de heridas diafragmáticas en pacientes con trauma toracoabdominal penetrante hemodinámicamente estables. Materiales y métodos. Estudio prospectivo realizado en 119 pacientes atendidos en el Hospital Universitario del Valle, Cali, Colombia, entre marzo de 2012 y junio de 2015. Para evaluar el rendimiento diagnóstico de la TCMD, los resultados obtenidos mediante esta prueba fueron comparados con los reportados por el test de referencia (cirugía abierta). Se realizaron 2 lecturas de los estudios de imagen por 2 radiólogos. La concordancia intra e interobservador respecto a la lectura de las TCMD se analizó mediante el coeficiente Kappa de Fleiss. Resultados. La TCDM tuvo una sensibilidad y especificidad de 94.4% y 46.8%, respectivamente. Sus valores predictivos positivo (VPP) y negativo (VPN) fueron 44.7% y 94.8%, respectivamente. La razón de verosimilitud positiva (LR+) fue 1.7765, y la razón de verisimilitud negativa (LR-), 0.1186. Respecto a la concordancia interobservador, el coeficiente Kappa de Fleiss entre la primera lectura de ambos radiólogos fue de 0.4425. Conclusiones. La especificidad de la TCMD para el diagnóstico de heridas diafragmáticas encontrada en el presente estudio difiere considerablemente de lo reportado en la literatura. Teniendo en cuenta la sensibilidad, el VPN y la LR- obtenidos en el presente estudio, la TCMD podría constituir una herramienta importante en el manejo de estos pacientes, ya que en aquellos en los que no se detecte herida diafragmática mediante este tipo de tomografía podría considerarse un manejo conservador.

Three-dimentional radiographic features of 67 maxillary radicular cysts / 北京大学学报(医学版)

OBJECTIVE@#To analyze the three-dimensional radiographic characteristics of maxillary radi-cular cysts using cone-beam computed tomography (CBCT) and spiral CT.@*METHODS@#Clinical records, histopathological reports, and CBCT or non-enhanced spiral CT images of 67 consecutive patients with maxillary radicular cysts were retrospectively acquired, and radiographic features, including size, shape, expansion, internal structure and relationship with the surrounding tissues, were analyzed. The lesions were divided into three types according to the involved tooth number, as follows: type Ⅰ (single tooth), the epicenter of the cyst was located at the apex of a nonvital tooth, without involvement of the neighbo-ring tooth; type Ⅱ (adjacent tooth involvement), the cyst was located at the apex of a nonvital tooth with involvement of the mesial and/or distal tooth root; and type Ⅲ (multi-teeth), the cyst involved the apexes of ≥4 teeth. Besides, these cysts were classified as another three types on sagittal views, as follows: centripetal, the root apex was oriented centripetally to the center of the cyst; palatal, the cyst was located mainly at the palatal side of the apex; and labial/buccal, the cyst was located mainly at the labial/buccal side of the apex.@*RESULTS@#Totally, 67 patients with maxillary radicular cysts were acquired, including 38 males and 29 females, and their ages ranged from 13 to 77 years. Among them, 46 lesions (68.7%) were located in the anterior maxilla and 65 (97.0%) were round or oval. Labial/buccal cortex expansion was present in 43 cases (64.2%) and palatal cortex expansion in 37 cases (55.2%). The nasal floor was invaded in 27 cases (40.3%), the maxillary sinus was invaginated in 26 cases (38.8%), and root resorption was present in 9 cases (13.4%). The average diameter of lesions was (20.89±8.11) mm mesio-distally and (16.70±5.88) mm bucco-palatally. In spite of the 4 residual cysts, the remaining 63 lesions included 14 type Ⅰ, 26 type Ⅱ and 23 type Ⅲ cysts according to the involved tooth number. Besides, the 63 lesions included 46 centripetal, 15 palatal and 2 buccal cysts on sagittal views.@*CONCLUSION@#The maxillary radicular cysts were frequently well-circumscribed round or oval radiolucency, with significantly different sizes. According to the involved tooth number, it can be divided into single tooth, adjacent tooth involvement and multi-teeth types. On sagittal views, the root-cyst relationship was centripetal in most cases, while a minority of cysts expanded palatally or buccally.

The diffuse idiopathic skeletal hyperostosis classification based on CT and the correlation of ossification and sagittal spinal morphology / 中华骨科杂志

Objective:To investigate CT classification of diffuse idiopathic skeletal hyperostosis (DISH), and to analyze the correlation between the position of ossification in the anterolateral spine and the sagittal configuration of the spine.Methods:The medical records of 109 patients (70 male and 39 female) who underwent whole spine computerized tomography (CT) from October 2018 to October 2020 were retrospectively analyzed. The average age was 68.4±6.9 years old, ranging from 60 to 88 years old. High resolution CT volume rendering technique images were used to assess the degree of anterolateral spinal ossification in each vertebral space, and a CT grading system was established. Sagittal parameters such as thoracic kyphosis (TK), lumbar lordosis(LL), cervical lordosis (CL), sacral slope (SS), and thoracolumbar junction angle (TLJ) of the patients were measured. The sagittal morphology of the spine was divided into four types using the modified Abelin-Genevois (AG) sagittal classification. In AG type 1 patients, the kyphotic vertex was located in the middle of the thoracic spine (T 4-T 11). In AG type 2 patients, there was no significant kyphotic vertex. In AG type 3 patients, the kyphotic vertex was located in the thoracolumbar segment (T 12-L 2). In AG type 4 patients, the kyphotic vertex was located in the upper thoracic segment (T 1-T 3). Inter-observer and intra-observer reliability were calculated by intra-group correlation coefficient ( ICC). Statistical analysis was conducted to investigate the correlation between different AG types and ossification location and severity. Results:The new DISH grading system classifies the severity of anterolateral spinal ossification in each intervertebral space into grades 0 to 3 with an intra-observer ICC value of 0.871 and inter-observer ICC value of 0.874. Combined with Resnick's DISH diagnostic criteria, 97 patients (89.0%) in this study had four consecutive intervertebral spaces with ossification grade 1 or above. For these patients, in T 4-T 11, the standardized ossification grade of AG type 1 was 1.24±0.69, greater than that of AG type 2 (0.84±0.71) and AG type 3 (1.00±0.70), and the differences were statistically significant ( F=23.101, P<0.001). In T 12-L 2, the standardized ossification grade of AG type 3 was 1.44±0.87, which was higher than AG type 1 (1.06±0.84) and AG type 2 (0.72±0.63), the differences were statistically significant ( F=14.008, P<0.001). In this study, no patients with kyphosis apex in the cervicothoracic region (AG type4) were found. In T 1-T 3, there was no statistical difference between the three groups ( F=0.303, P=0.738); in the whole thoracic and lumbar spine (T 1-L 5), there was statistically significant difference in the total ossification grade ( F=14.374, P<0.001), there was no statistical difference between AG type 1 and AG type 3 ( P=0.254), both of which were higher than AG type 2 ( P<0.001). Conclusion:The new DISH ossification grading system proposed in this study has high credibility, which can be used in DISH's study. This study confirmed that the region where the apex of kyphosis is located is prone to anterolateral ossification of the spine.

Predictive value of vertebral trabecular and endplate Hounsfield Units on cage subsidence followed posterior lumbar interbody fusion / 中华骨科杂志

Objective:To explore the predictive value of vertebral trabecular and endplate HU values on cage subsidence after posterior lumbar interbody fusion (PLIF), hope to provide reference for surgical planning.Methods:All of 72 patients with lumbar disc herniation that underwent PLIF were retrospectively reviewed, who were divided into two groups according to the occurrence of cage subsidence at one-year follow up. Cage subsidence was defined as more than 4 mm subsidence into the vertebrae valuated by CT at one-year follow up. There were 18 patients enrolled into Subsidence group and 54 patients enrolled into N-Subsidence group. The lumbar lordosis, segmental lordosis, intervertebral height, off-bed time, hospital stay, complications, the trabecular and endplate HU values of upper instrumented vertebrae (UIV) and lower instrumented vertebrae (LIV) were compared between the two groups. ROC was used to explore the thresholds of HU values.Results:There were 14 patients presented cage subsidence into the L4, 4 patients presented cage subsidence into the L5. There was no significant difference in lumbar lordosis, segmental lordosis, intervertebral height, off-bed time, hospital stay, or complications between the two groups. Both UIV and LIV trabecular and endplate showed a lower HU value in Subsidence group than those in N-Subsidence group. The most appropriate thresholds of HU value were 146, 172, 307, 254 for trabecular of UIV, trabecular of LIV, lower endplate of UIV, and upper endplate of LIV, respectively.Conclusion:Vertebral trabecular and endplate HU values could effectively predict the cage subsidence after PLIF, patients should be completely informed the risk of cage subsidence and larger cage should be recommended if they presented HU values under the certain threshold.

Application of individual head-rest combined with thermoplastic fixation mask in position fixation for irradiation with helical tomotherapy for head and neck tumors / 中国基层医药

Objective:To compare the positioning errors of individual head-rest combined with thermoplastic fixation mask versus thermoplastic fixation mask alone in patients with head and neck tumors. Methods:Twenty-eight patients who received irradiation with helical tomotherapy in Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital) between October 2019 and April 2020 were included in this study. They were randomly assigned to receive position fixation with either individual head-rest combined with thermoplastic fixation mask (N1 group, n = 14) or thermoplastic fixation mask alone (N2 group, n = 14). Megavoltage computed tomography (MVCT) scanning registration was used to obtain the positioning errors in translation and rotation (ROLL) in the left-right (X), head-food (Y), and belly-back (Z) directions. There were a total of 841 CT scans, consisting of 425 scans in group N1 and 416 scans in group N2. Results:The positioning errors in X, Y, Z and ROLL directions in the N1 group were (1.37 ± 1.04) mm, (1.38 ± 1.12) mm, (1.47 ± 1.62) mm and (1.47 ± 1.62) ° respectively, and they were (1.57 ± 1.21) mm, (2.10 ± 1.51) mm, (1.61 ± 1.50) mm and (1.40 ± 1.30) ° respectively in the N2 group. There was significant difference in positioning errors in the Y direction between N1 and N2 groups ( P = 0.013). In the N1 group, the outward expansion boundaries in X, Y and Z directions was 4.15 mm, 4.23 mm and 4.81 mm respectively, and it was 4.77, 6.31 and 5.08 mm, respectively in the N2 group. In the X direction, there was significant difference in positioning errors taking 3 mm as the dividing point between N1 and N2 groups ( χ2 = 10.516, P < 0.001). In the Y direction, there was significant difference in positioning errors taking 1, 2 and 3 mm as the dividing points between N1 and N2 groups ( χ2 = 24.889, P < 0.001; χ2 = 42.202, P < 0.001; χ2 = 46.204, P < 0.001). In the Z direction, there was significant difference in positioning errors taking 2 mm as the dividing point between N1 and N2 groups ( χ2 = 7.335, P = 0.007). In the N1 group, the percentage of positioning errors < 3 mm in the X, Y and Z directions was 92%, 90% and 92%, respectively. Conclusion:Compared with thermoplastic fixation mask alone, individual head-rest combined with thermoplastic fixation mask can better effectively improve the positioning stability and reduce positioning errors in patients receiving irradiation with helical tomotherapy for head and neck tumors. The combined method is of certain innovation.