Clinical and imaging features of desmoid tumors of the extremities

BACKGROUND Desmoid fibroma is a rare soft tissue tumor originating from the aponeurosis,fascia,and muscle,and it is also known as aponeurotic fibroma,invasive fibroma,or ligamentous fibroma.AIM To investigate the clinical and imaging features of desmoid tumors of the extremities.METHODS Thirteen patients with desmoid fibroma of the extremities admitted to our hospital from October 2016 to March 2021 were included.All patients underwent computed tomography(CT),magnetic resonance imaging(MRI),and pathological examination of the lesion.Data on the diameter and distribution of the lesion,the relationship between the lesion morphology and surrounding structures,MRI and CT findings,and pathological features were statistically analyzed.RESULTS The lesion diameter ranged from 1.7 to 8.9 cm,with an average of 5.35±2.39 cm.All lesions were located in the deep muscular space,with the left and right forearm each accounting for 23.08%of cases.Among the 13 patients with desmoid fibroma of the extremities,the lesions were"patchy"in 1 case,irregular in 10,and quasi-round in 2.The boundary between the lesion and surrounding soft tissue was blurred in 10 cases,and the focus infiltrated along the tissue space and invaded the adjacent structures.Furthermore,the edge of the lesion showed"beard-like"infiltration in 2 cases;bone resorption and damage were found in 8,and bending of the bone was present in 2;the boundary of the focus was clear in 1.According to the MRI examination,the lesions were larger than 5 cm(61.54%),round or fusiform in shape(84.62%),had an unclear boundary(76.92%),showed uniform signal(69.23%),inhomogeneous enhancement(84.62%),and"root"or"claw"infiltration(69.23%).Neurovascular tract invasion was present in 30.77%of cases.CT examination showed that the desmoid tumors had slightly a lower density(69.23%),higher enhancement(61.54%),and unclear boundary(84.62%);a CT value<50 Hu was present in 53.85%of lesions,and the enhancement was uneven in 53.85%of cases.Microscopically,fibroblasts and myofibroblasts were arranged in strands and bundles,without obvious atypia but with occasional karyotyping;cells were surrounded by collagen tissue.There were disparities in the proportion of collagen tissue in different regions,with abundant collagen tissue and few tumor cells in some areas,similar to the structure of aponeuroses or ligaments,and tumor cells invading the surrounding tissues.CONCLUSION Desmoid tumors of the extremities have certain imaging features on CT and MRI.The two imaging techniques can be combined to improve the diagnostic accuracy,achieve a comprehensive diagnosis of the disease in the clinical practice,and reduce the risk of missed diagnosis or misdiagnosis.In addition,their use can ensure timely diagnosis and treatment.

Preliminary Evaluation of Hemodynamic Effects of Fontan Palliation on Renal Artery Using Computational Fluid Dynamics

Background:The assessment of renal function is important to the prognosis of patients needing Fontan palliation due to the reconstructed compromised circulation.To know the relationship between the kidney perfusion and hemodynamic characteristics during surgical design could reduce the risk of acute kidney injury(AKI)and the postoperative complications.However,the issue is still unsolved because the current clinical evaluation methods are unable to predict the hemodynamic changes in renal artery(RA).Methods:We reconstructed a three-dimensional(3D)vascular model of a patient requiring Fontan palliation.The technique of computational fluid dynamics(CFD)was utilized to explore the changes of RA hemodynamics under different possible blood flow rates.The relationship between the kidney perfusion and hemodynamic characteristics was investigated.Results:The calculated results indicated the declined tendency of the pressure and pressure drop as the flow rate decreased.When the flow rate decreased to two-thirds of its baseline,both the pressure of left renal artery(LRA)and the pressure of right renal artery(RRA)dipped below 50%,and the pressure of RRA fell more quickly than that of LRA.Uneven distribution of WSS was observed on the trunk of RA,and the lowest WSS was found at the distal of RA.The average WSS in RA dropped to around 50%as the flow rate reached one-third of its baseline.Conclusions:As a promising approach,CFD can be utilized to quantitatively evaluate the hemodynamic characteristics of RA and contribute to offsetting the drawbacks of clinical assessments of renal function,to help realize better prognosis for the patients with Fontan palliation.

Evaluation of CT findings for the differentiation of benign from malignant primary retroperitoneal tumors

Background Benign and malignant primary retroperitoneal tumors （RT） have different pathological manifestations,and overlapping imaging characteristics.This study aimed to evaluate the value of computed tomography （CT） for differentiating benign from malignant RT.Methods One hundred and ninety-four patients with clinical and radiographic data were evaluated retrospectively following surgical resection of primary RT.There were 38.1％ （n=74） benign lesions and 61.9％ （n=120） malignant lesions.Categorical variables were tested with a chi-square test or Fisher＇s exact test for the diagnostic indexes and sensitivity and specificity of CT characteristics.Results In univariate analysis,the differences in ill-defined margins,irregular surfaces,long diameter ＞6.75 cm,short diameter ＞6.25 cm,and solid or mixed texture had statistical significance; the sensitivity and specificity were 44.2％ and 91.9％,70.0％ and 62.2％,68.8％ and 60.7％,59.7％ and 74.2％,87.5％ and 35.1％,respectively.In multivariate analysis,a combination of all the above indexes was the best model for differentiating malignant tumors,resulting in the most accurate diagnosis of malignancies with a sensitivity of 77.2％ and a specificity of 81.1％ （P＜0.0001） when the score was 4.The differences in other findings including CT attenuation,number,and calcification had no statistical significance.The unique characteristics included the spotted enhancement （mottled high density）in schwannoma （P＜0.0001）,adipose tissue in liposarcoma （P＜0.0001）and paravertebral location in neurogenic tumors （P＜0.0001）.Conclusions More accurate differential diagnosis of primary RT can be made through comprehensive analysis of the combined diagnostic indexes of CT.Some specific characteristics of CT can assist in preoperative planning.

Evaluation with low-dose dual-phase helical computed tomography of patients with thyroid lesions

Background The incidence of thyroid cancer has been increasing.Our aim was to evaluate the efficacy of low-dose dualphase helical computed tomography （CT） in the characterization of thyroid lesions,and to discuss the relationship between image characteristics and their pathology.Methods One hundred and six patients with thyroid lesions underwent low-dose dual-phase helical CT after the injection of contrast material.CT scans were obtained at arterial and venous phase with delays of 25 and 65 seconds,and tube current of 60 and 120 mA,respectively.The attenuation change in the lesion between the arterial and venous phase was analyzed and categorized as ＂increased,＂ ＂decreased,＂ ＂mixed＂ or ＂no change.＂ Results Histopathologic diagnosis was obtained by surgery in 106 patients （115 lesions）.Of the 106 patients,45 had nodular goiter,5 thyroid adenoma,6 thyroiditis,and 50 papillary thyroid carcinoma （PTC） （59 lesions）.The attenuation value showed a significant difference （P ＜0.05） between the arterial and venous phase for the high attenuation area.There was statistical significant difference in terms of attenuation value in high attenuation areas at both phases and in low attenuation areas on arterial phase between nodular goiter and PTC （P ＜0.05）.However,there was no significant difference in attenuation value between adenoma and PTC.Twenty-nine cases （76.3％） of goiter manifested mixed type,3 cases （3/5） of adenoma showed decreased type,6 cases （6/6） of thyroiditis showed increased type,and 55 cases （93.2％） of PTC showed decreased type attenuation.The sensitivity,specificity for thyroid carcinoma by dual-phase CT were 94.9％ and 80.4％ respectively.The overall diagnostic accuracy for thyroid lesions by dual-phase CT was 87.8％.Conclusions The performance of dual-phase helical CT is related to the pathological structure of the lesions.The analysis of enhancement patterns by using dual-phase helical CT will be helpful in the differential diagnosis of thyroid lesions.