Fat-suppressed T2-weighted Images Research Articles

Value of conventional magnetic resonance imaging texture analysis in the differential diagnosis of benign and borderline/malignant phyllodes tumors of the breast

BackgroundThe purpose of this study was to determine the potential value of magnetic resonance imaging (MRI) texture analysis (TA) in differentiating between benign and borderline/malignant phyllodes tumors of the breast.MethodsThe preoperative MRI data of 25 patients with benign phyllodes tumors (BPTs) and 19 patients with borderline/malignant phyllodes tumors (BMPTs) were retrospectively analyzed. A gray-level histogram and gray-level cooccurrence matrix (GLCM) were used for TA with fat-suppressed T2-weighted imaging (FS-T2WI), diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC) images, and 2- and 7-min postcontrast T1W images on dynamic contrast-enhanced MRI (DCE-T1WI2min and DCE-T1WI7min) between BPTs and BMPTs. Independent sample t-test and Mann-Whitney U test were performed for intergroup comparison. A regression model was established by using binary logistic regression analysis, and receiver operating characteristic (ROC) curve analysis was carried out to evaluate diagnostic efficiency.ResultsFor ADC images, the texture parameters angular second moment (ASM), correlation, contrast, entropy and the minimum gray values of ADC images (ADCMinimum) showed significant differences between the BPT group and BMPT group (all p<0.05). The parameter entropy of FS-T2WI and the maximum gray values and kurtosis of the tumor solid region of DCE-T1WI7min also showed significant differences between these two groups. Except for ADCMinimum, angular second moment of FS-T2WI (FS-T2WIASM), and the maximum gray values of DCE-T1WI7min (DCE-T1WI7min-Maximum) of the tumor solid region, the AUC values of other positive texture parameters mentioned above were greater than 0.75. Binary logistic regression analysis demonstrated that the contrast of ADC images (ADCContrast) and entropy of FS-T2WI (FS-T2WIEntropy) could be considered independent texture variables for the differential diagnosis of BPTs and BMPTs. Combined, the AUC of these parameters was 0.891 (95% CI: 0.793–0.988), with a sensitivity of 84.2% and a specificity of up to 89.0%.ConclusionTexture analysis could be helpful in improving the diagnostic efficacy of conventional MR images in differentiating BPTs and BMPTs.

A dermoid cyst misdiagnosed as a lipoma due to atypical magnetic resonance images: a case report

BackgroundDermoid cysts are well-known lesions that manifest as subcutaneous tumors around the lateral sides of the eyebrows in young patients. Computed tomography or magnetic resonance imaging (MRI) is often performed to confirm the diagnosis. On the other hand, a lipoma is usually a circular lesion, which is sometimes observed in the upper part of the face. The signals of both T1-weighted and T2-weighted images of MRI of a lipoma are, in general, relatively highly homogenous, and the signals decrease in fat-suppressed images. Therefore, differential diagnosis between a dermoid cyst and a lipoma is usually made with MRI, especially based on fat-suppressed images. Here, we present a case of misdiagnosis of a dermoid cyst as a lipoma because of atypical magnetic resonance images.Case presentationWe report a case of a 24-year-old Japanese woman with a dermoid cyst around the lateral edge of the eyebrow. The cyst had been gradually increasing in size for the past 2 years. On MRI, it showed high internal signals on T1- and T2-weighted images. However, the signal intensity decreased homogeneously in the fat-suppressed T2-weighted images. The observed tumor had a yellowish appearance under the endoscope. On the basis of these findings, the lesion was considered a lipoma until it ruptured intraoperatively. The pathological diagnosis confirmed it to be a dermoid cyst.ConclusionSome dermoid cysts contain lipid-rich liquid, and these may be misdiagnosed as lipomas by MRI. When a tumor is located at a common site for a dermoid cyst, the MRI images should be validated carefully if it appears like a lipoma, and the differential diagnosis should be considered carefully.

Magnetic Resonance Imaging-Based Radiomics Nomogram for Prediction of the Histopathological Grade of Soft Tissue Sarcomas: A Two-Center Study.

Preoperative prediction of soft tissue sarcoma (STS) grade is important for treatment decisions. Therefore, formulation an STS grade model is strongly needed. To develop and test an magnetic resonance imaging (MRI)-based radiomics nomogram for predicting the grade of STS (low-grade vs. high grade). Retrospective POPULATION: One hundred and eighty patients with STS confirmed by pathologic results at two independent institutions were enrolled (training set, N=109; external validation set, N=71). Unenhanced T1-weighted (T1WI) and fat-suppressed T2-weighted images (FS-T2WI) were acquired at 1.5T and 3.0T. Clinical-MRI characteristics included age, gender, tumor-node-metastasis (TNM) stage, American Joint Committee on Cancer (AJCC) stage, progression-free survival (PFS), and MRI morphological features (ie, margin). Radiomics feature extraction were performed on T1WI and FS-T2WI images by minimum redundancy maximum relevance (MRMR) method and least absolute shrinkage and selection operator (LASSO) algorithm. The selected features constructed three radiomics signatures models (RS-T1， RS-FST2, and RS-Combined). Univariate and multivariate logistic regression analysis were applied for screening significant risk factors. Radiomics nomogram was constructed by incorporating the radiomics signature and risk factors. Clinical-MRI characteristics were performed by a univariate analysis. Model performances (discrimination, calibration, and clinical usefulness) were validated in the external validation set. The RS-T1 model, RS-FST2 model, and RS-Combined model had an area under curves (AUCs) of 0.645, 0.641, and 0.829, respectively, in the external validation set. The radiomics nomogram, incorporating significant risk factors and the RS-Combined model had AUCs of 0.916 (95%CI, 0.866-0.966, training set) and 0.879 (95%CI, 0.791-0.967, external validation set), and demonstrated good calibration and good clinical utility. The proposed noninvasive MRI-based radiomics models showed good performance in differentiating low-grade from high-grade STSs. 3 TECHNICAL EFFICACY STAGE: 2.

"Anterior-shift sign": a novel MRI finding of adult hip dysplasia.

In adult hip dysplasia, methods for direct evaluation of hip instability have not been established. The present study aimed to determine findings suggestive of hip instability on magnetic resonance imaging (MRI) and to evaluate their correlations with clinical and radiological factors. We retrospectively reviewed 72 hips in 50 patients with hip dysplasia (45 females, 5 males; mean age: 40.0years; age range: 15-59years; Kellgren-Lawrence grade: ≤ 2). Hip dysplasia was defined as a lateral center-edge angle < 25°. Among the hips, 50 had pain (symptomatic dysplasia group) and 22 were asymptomatic (asymptomatic dysplasia group). As controls, 12 normal hips in 12 patients who underwent screening for asymptomatic osteonecrosis of the femoral head by MRI were evaluated. Using an oblique axial view on fat-suppressed T2-weighted images, we evaluated the presence of a gap between the posterior part of the femoral head and the corresponding acetabular surface, indicating hip instability (anterior-shift sign). The correlations of anterior-shift sign with clinical and radiographical factors were examined. Anterior-shift sign was observed in 92.0% in the symptomatic dysplasia group, 9.1% in the asymptomatic dysplasia group, and 0% in the control group. In adult hip dysplasia, cases with anterior-shift sign had significantly more pain and labrum tear occurrence than cases without anterior-shift sign. Anterior-shift sign was correlated with Kellgren-Lawrence grade and degree of acetabular coverage. This study suggested that hip instability can be observed as the anterior-shift sign on MRI. This sign is useful when considering indications for periacetabular osteotomy in adult hip dysplasia.

Evaluating Heterogeneity of Primary Lung Tumor Using Clinical Routine Magnetic Resonance Imaging and a Tumor Heterogeneity Index.

ObjectiveTo improve the assessment of primary tumor heterogeneity in magnetic resonance imaging (MRI) of non-small cell lung cancer (NSCLC), we proposed a method using basic measurements from T1- and T2-weighted MRI.MethodsOne hundred and four NSCLC patients with different T stages were studied. Fifty-two patients were analyzed as training group and another 52 as testing group. The ratios of standard deviation (SD)/mean signal value of primary tumor from T1-weighted (T1WI), T1-enhanced (T1C), T2-weighted (T2WI), and T2 fat suppression (T2fs) images were calculated. In the training group, correlation analyses were performed between the ratios and T stages. Then an ordinal regression model was built to generate the tumor heterogeneous index (THI) for evaluating the heterogeneity of tumor. The model was validated in the testing group.ResultsThere were 11, 32, 40, and 21 patients with T1, T2, T3, and T4 disease, respectively. In the training group, the median SD/mean on T1WI, T1C, T2WI, and T2fs sequences was 0.11, 0.19, 0.16, and 0.15 respectively. The SD/mean on T1C (p=0.003), T2WI (p=0.000), and T2fs sequences (p=0.002) correlated significantly with T stages. Patients with more advanced T stage showed higher SD/mean on T2-weighted, T2fs, and T1C sequences. The median THI in the training group was 2.15. THI correlated with T stage significantly (p=0.000). In the testing group, THI was also significantly related to T stages (p=0.001). Higher THI had relevance to more advanced T stage.ConclusionsThe proposed ratio measurements and THI based on MRI can serve as functional radiomic markers that correlated with T stages for evaluating heterogeneity of lung tumors.

Dixon-T2WI magnetic resonance imaging at 3tesla outperforms conventional imaging for thyroid eye disease.

To determine the diagnostic performances of a single Dixon-T2-weighted imaging (WI) sequence compared to a conventional protocol including T1-, T2-, and fat-suppressed T2-weighted MRI at 3T when assessing thyroid eye disease (TED). This IRB-approved prospective single-center study enrolled participants presenting with confirmed TED from April 2015 to October 2019. They underwent an MRI, including a conventional protocol and a Dixon-T2WI sequence. Two neuroradiologists, blinded to all data, read both datasets independently and randomly. They assessed the presence of extraocular muscle (EOM) inflammation, enlargement, fatty degeneration, or fibrosis as well as the presence of artifacts. The Wilcoxon signed-rank test was used. Two hundred six participants were enrolled (135/206 [66%] women, 71/206 [34%] men, age 52.3±13.2 years). Dixon-T2WI was significantly more likely to detect at least one inflamed EOM as compared to the conventional set (248/412 [60%] versus 228/412 [55%] eyes; (p= 0.02). Dixon-T2WI was more sensitive and specific than the conventional set for assessing muscular inflammation (100% versus 94.7% and 71.2% versus 68.5%, respectively). Dixon-T2WI was significantly less likely to show major or minor artifacts as compared to fat-suppressed T2WI (20/412 [5%] versus 109/412 [27%] eyes, p< 0.001, and 175/412 [42%] versus 257/412 [62%] eyes, p< 0.001). Confidence was significantly higher with Dixon-T2WI than with the conventional set (2.35 versus 2.24, p= 0.003). Dixon-T2WI showed higher sensitivity and specificity and showed fewer artifacts than a conventional protocol when assessing thyroid eye disease, in addition to higher self-reported confidence. • Dixon-T2WI has better sensitivity and specificity than a conventional protocol for assessing inflamed extraocular muscles in patients with thyroid eye disease. • Dixon-T2WI shows significantly fewer artifacts than fat-suppressed T2WI. • Dixon-T2WI is faster and is associated with significantly higher self-reported reader confidence as compared to a conventional protocol when assessing inflammatory extraocular muscles.

Pre-treatment MRI predictor of high-grade malignant parotid gland cancer.

We aimed to evaluate pre-treatment MRI predictors of high-grade malignant parotid gland cancer by comparing MRI findings and texture parameters between high-grade and intermediate/low-grade parotid gland cancers. Patients underwent a pre-treatment MRI and had a parotid gland cancer resection with pathological evaluation. Evaluation objectives included attributive factors such as age and gender, several MRI findings of T1- and T2-weighted images, post-contrast fat suppression T1-weighted images, ADC value and 40 texture parameters calculated from T2-weighted axial images. Such objects were compared between high-grade and intermediate/low-grade lesions. Of the parotid gland cancers surveyed, 39 were included for analysis. Of these, 18 were high-grade lesions, 2 were intermediate-grade lesions, and 19 were low-grade lesions. The high-grade group was significantly older than the low- and intermediate-grade groups (p = 0.01). There were more males in the high-grade group than in the low- and intermediate-grade groups (p = 0.01). There were also significantly more MRI findings of neck lymph node metastases in the high-grade group than in the low- and intermediate-grade groups (p < 0.001). Other MRI findings and texture parameters did not show significant differences between the two groups (p = 0.07-1.00). Morphological assessment on MRI and texture parameters alone is not sufficient to estimate the grade of parotid cancer. MRI findings of neck lymph node metastases, as well as patient characteristics such as age (older patients) and gender (male) can be suggestive of high-grade parotid gland cancer in pre-treatment evaluation.

Epidermoid cyst arising in the mandibular ramus: A case report

Introduction: Dermoid and epidermoid cysts are developmental lesions derived from the ectoderm. In acquired elements, trauma and inflammation are hypothesized mechanisms of onset. In the oral region, these cysts mainly develop in the soft tissues such as floor of the mouth, moreover, it is relatively rare in the mandible. Among them, it is extremely rare in the ramus. Case Report: A 48-year-old woman visited dental clinic because of occlusal pain of the left wisdom tooth. The panoramic X-ray film showed an oval-shaped radiolucent area in the left mandibular ramus. Computed tomography revealed radiolucent area in the left mandibular ramus, moreover, there was no bone destruction. Magnetic resonance imaging revealed a lesion measuring 18×17×21 mm in size with mixed moderate and high signal intensity on fat-suppressed T2-weighted imaging in the left mandibular ramus. Gadolinium contrast-enhanced T1-weighted imaging showed no clear enhancement. On the basis of imaging findings, cystic lesion was diagnosed. We performed cystectomy and extraction of the lower wisdom teeth under general anesthesia. Histopathologic examination of the resected specimen revealed the unilocular cyst lined keratinized squamous epithelium. There were no adnexal skin structures such as sweat grand, sebaceous glands, and hair follicles. In addition, the lesions were not associated with teeth and were found only in the mandibular ramus. From these results, it was finally diagnosed as the epidermoid cyst. Three years and six months have passed, but there is no recurrence and a radiolucent area in the panoramic X-ray film shows increased radiopaque. Computed tomography revealed that the defect of the bone is reduced. The postoperative course was uneventful. Conclusion: There is a large amount of literature on jaw diseases; however, we may still come across unique and unclear cases. Clinical examinations, conventional radiography, and surgical experience are not sufficient for the diagnosis of all pathologies. Our case is very rare and is a unique case in the relevant literature because the lesion was limited to the mandibular ramus above the mandibular foramen and was not associated with teeth.

Convolutional neural network for discriminating nasopharyngeal carcinoma and benign hyperplasia on MRI.

A convolutional neural network (CNN) was adapted to automatically detect early-stage nasopharyngeal carcinoma (NPC) and discriminate it from benign hyperplasia on a non-contrast-enhanced MRI sequence for potential use in NPC screening programs. We retrospectively analyzed 412 patients who underwent T2-weighted MRI, 203 of whom had biopsy-proven primary NPC confined to the nasopharynx (stage T1) and 209 had benign hyperplasia without NPC. Thirteen patients were sampled randomly to monitor the training process. We applied the Residual Attention Network architecture, adapted for three-dimensional MR images, and incorporated a slice-attention mechanism, to produce a CNN score of 0-1 for NPC probability. Threefold cross-validation was performed in 399 patients. CNN scores between the NPC and benign hyperplasia groups were compared using Student's t test. Receiver operating characteristic with the area under the curve (AUC) was performed to identify the optimal CNN score threshold. In each fold, significant differences were observed in the CNN scores between the NPC and benign hyperplasia groups (p < .01). The AUCs ranged from 0.95 to 0.97 with no significant differences between the folds (p = .35 to .92). The combined AUC from all three folds (n = 399) was 0.96, with an optimal CNN score threshold of > 0.71, producing a sensitivity, specificity, and accuracy of 92.4%, 90.6%, and 91.5%, respectively, for NPC detection. Our CNN method applied to T2-weighted MRI could discriminate between malignant and benign tissues in the nasopharynx, suggesting that it as a promising approach for the automated detection of early-stage NPC. • The convolutional neural network (CNN)-based algorithm could automatically discriminate between malignant and benign diseases using T2-weighted fat-suppressed MR images. • The CNN-based algorithm had an accuracy of 91.5% with an area under the receiver operator characteristic curve of 0.96 for discriminating early-stage T1 nasopharyngeal carcinoma from benign hyperplasia. • The CNN-based algorithm had a sensitivity of 92.4% and specificity of 90.6% for detecting early-stage nasopharyngeal carcinoma.

Comparison of MR findings of acute traumatic peripheral nerve injury and acute compressive neuropathy in a rat model

PurposeThe treatment strategy is different for acute traumatic peripheral nerve injury and acute compressive neuropathy. This study aimed to compare magnetic resonance imaging (MRI) features of acute traumatic peripheral nerve injury and acute compressive neuropathy in a rat model.Materials and methodsTwenty female Sprague-Dawley rats were divided into two groups. In the crush injury group (n = 10), the unilateral sciatic nerve was crushed using forceps to represent acute traumatic peripheral nerve injury. In the compression injury group (n = 10), the unilateral sciatic nerve was ligated using silk to represent acute compressive neuropathy. The MRI of eight rats from each group were acquired on postoperative days 3 and 10. Fat-suppressed T2-weighted images were acquired. Changes in the injured nerve were divided into three grades. A Fisher’s exact test was used to compare the changes in the nerves of the two groups. Histological staining and a western blot analysis were performed on one rat in each group on day 3. Neurofilament, myelin basic protein (MBP), and p75NTR staining were performed. Expression of neurofilament, MBP, p75NTR, and c-jun was evaluated by western blot analysis.ResultsMR neurography revealed substantial nerve changes in the compression injury group compared with the crush injury group at two-time points (p = 0.001 on day 3, p = 0.026 on day 10). The histopathological analysis indicated the destruction of the axon and myelin, mainly at the injury site and the distal portion of the injury in the crush injury group. It was prominent in the proximal portion, the injury site, and the distal portion of the injury in the compression injury group. The degree of axonal and myelin destruction was more pronounced in the compression injury group than in the crush injury group.ConclusionMR neurography showed prominent and long-segmental changes associated with the injured nerve in acute compressive neuropathy compared with acute traumatic peripheral nerve injury.

Comparison between 3-point Dixon- and CHESS-based OMERACT-recommended MRI protocols in hands of patients with suspicion of early rheumatoid arthritis

PurposeTo compare fat suppression effectiveness, image quality and disease activity scores between MRI protocols based on the Dixon method and the Chemical Shift Selective (CHESS) technique in hands of patients with suspicion of early rheumatoid arthritis (RA). MethodBoth hands of 28 patients (19 women; mean age 45.2 years old) with suspicion of early RA were prospectively imaged with Dixon- and CHESS-based OMERACT recommended protocols at 1.5 T including fat-suppressed T2-weighted and contrast-enhanced T1-weighted imaging. Two radiologists (R1/R2) separately assessed effectiveness of fat suppression and determined RAMRIS scores woth the Dixon- and CHESS-based protocols. R1 repeated the RAMRIS scoring and measured contrast-to-noise ratios (CNRs) on Dixon and CHESS images. Statistics included 2-way ANOVA test for the comparison of CNRs and Bland-Altman methodology for inter-technique and intra-observer agreement (p < 0.05). ResultsFat suppression failure occurred in up to 1 patient with the Dixon- and 25 patients with the CHESS-based protocols. CNRs were significantly higher on T1-weighted and lower on T2-weighted Dixon images than on the corresponding CHESS images (p ≤ 0.042). Median bias of the difference between Dixon- and CHESS-based RAMRIS scores was not significantly different from 0 (−0.8 to +1.0 and −1.1 to +1.4 for R1/R2). Median bias of the difference between RAMRIS scores at first and second readings was significantly different from 0 with the CHESS-based protocols (−0.8 to +1.7) but not with the Dixon-based protocols (+0.0 to +1.0). ConclusionsDixon sequences yield more effective fat suppression and more reproducible RAMRIS scoring than CHESS sequences in hands with suspicion of early RA.

Magnetic resonance imaging findings of carcinoma arising from anal fistula: A retrospective study in a single institution.

BACKGROUNDMagnetic resonance imaging (MRI) is currently the standard investigation for suspected perianal diseases. Carcinoma arising from anal fistula is very rare, and early diagnosis is often difficult.AIMTo describe and summarize the MRI findings of carcinoma arising from anal fistula.METHODSIn this retrospective study, records of ten patients diagnosed with carcinoma arising from anal fistula and confirmed by surgery (n = 7) or biopsy (n = 3) between June 2006 and August 2018 were analyzed. All patients underwent preoperative pelvic MRI. Morphologic features, signal characteristics, fistula between the mass and the anus, contrast enhancement of mass, signal and enhancement of peritumoral areas, and regional lymphadenopathy were assessed.RESULTSAll ten tumors were solitary (8 mucinous adenocarcinomas and 2 adenocarcinomas). The maximum diameter of the tumors ranged from 3.4 cm to 12.4 cm (median: 4.15 cm; mean: 5.68 cm). Eight patients had a fistula between the mass and the anus. Contrast enhancement of the peritumoral areas was noted in three (3/5) patients. Perirectal or inguinal lymphadenopathy was noted in seven patients. Most lesions of mucinous adenocarcinoma were multiloculated and cauliflower-like, with a thin capsule and focally unclear boundary. They were markedly hyperintense on fat-suppressed T2WI, slightly hyperintense with focal hyperintensity on diffusion-weighted imaging (DWI), and hyperintense with focal hypointensity on apparent diffusion coefficient (ADC) map, with progressive mesh-like contrast enhancement. Adenocarcinomas had an infiltrative margin without a capsule and appeared heterogeneously hyperintense or slightly hyperintense on fat-suppressed T2WI, hyperintense on DWI, and hypointense on ADC map, with persistent heterogeneous enhancement.CONCLUSIONOur study highlighted several characteristic and potentially helpful MRI findings to diagnose carcinomas arising from anal fistula.

Noncontrast MRI of acute abdominal pain caused by gastrointestinal lesions: indications, protocol, and image interpretation.

Gastrointestinal tract lesions are major causes of acute abdominal pain. A rapid, accurate, and reliable diagnosis is required to manage patients. Magnetic resonance imaging (MRI) is a nonionizing modality that is beneficial for pregnant women, children, and young adults who are sensitive to ionizing radiation. For patients with renal impairment who are not accurately diagnosed with noncontrast computed tomography, noncontrast MRI can serve as an alternative diagnostic modality. MRI protocols used for acute abdominal pain are supposed to be optimized and prioritized to shorten scanning times. Single-shot T2-weighted and fat-suppressed T2-weighted imaging are important pulse sequences that are used to reveal pathology and inflammation in the gastrointestinal tract. Diffusion-weighted imaging clearly depicts inflammation and abscesses as hyperintense lesions. Most acute gastrointestinal tract lesions, including inflammation, ischemia, obstruction, and perforation, demonstrate bowel wall thickening. Bowel obstruction and adynamic ileus present bowel dilatation, and perforation and penetration show bowel wall defects. MRI can be used to reveal these pathological findings with some characteristics depending on their underlying pathophysiology. This review article discusses imaging modalities for acute abdominal pain, describes a noncontrast MRI protocol for acute abdominal pain caused by gastrointestinal tract lesions, and reviews MRI findings of acute gastrointestinal tract lesions.

Progressive Desmoid Tumor: Radiomics Compared With Conventional Response Criteria for Predicting Progression During Systemic Therapy-A Multicenter Study by the French Sarcoma Group.

OBJECTIVE. The response of desmoid tumors (DTs) to chemotherapy is evaluated with Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) in daily practice and clinical trials. MRI shows early change in heterogeneity in responding tumors due to a decrease in cellular area and an increase in fibronecrotic content before dimensional response. Heterogeneity can be quantified with radiomics. Our aim was to develop radiomics-based response criteria and to compare their performances with clinical and radiologic response criteria. MATERIALS AND METHODS. Forty-two patients (median age, 38.2 years) were included in this retrospective multicenter study because they presented with progressive DT and had an MRI examination at baseline, which we refer to as "MRI-0," and an early MRI evaluation performed after the first chemotherapy cycle (mean time after first chemotherapy cycle, 3 months [SD, 28 days]), which we refer to as "MRI-1." After signal intensity normalization, voxel size standardization, discretization, and segmentation of DT volume on fat-suppressed contrast-enhanced T1-weighted imaging, 90 baseline and delta 3D radiomics features were extracted. Using cross-validation and least absolute shrinkage and selection operator-penalized Cox regression, a radiomics score was generated. The performances of models based on the radiomics score, modified Response Evaluation Criteria in Solid Tumors, European Association for the Study of the Liver criteria, Cheson criteria, Choi criteria, and revised Choi criteria from MRI-0 to MRI-1 to predict progression-free survival (PFS, as defined by RECIST 1.1) were assessed with the concordance index. The results were adjusted for performance status, tumor volume, prior chemotherapy, current chemotherapy, and β-catenin mutation. RESULTS. There were 10 cases of progression. The radiomics score included four variables. A high score indicated a poor prognosis. The radiomics score independently correlated with PFS (adjusted hazard ratio = 5.60, p = 0.003), and none of the usual response criteria independently correlated with PFS. The prognostic model based on the radiomics score had the highest concordance index (0.84; 95% CI, 0.71-0.96). CONCLUSION. Quantifying early changes in heterogeneity through a dedicated radiomics score could improve response evaluation for patients with DT undergoing chemotherapy.

Quantification of Lumbar Spinal Canal Stenosis by Quantitative Fat-Suppressed Contrast-Enhanced Magnetic Resonance Imaging.

Fat-suppressed T1-weighted magnetic resonance images (MRIs) enhanced with gadolinium can evaluate the internal vertebral venous plexus and cauda equina. This study compared such findings with clinical situations and discusses whether these are helpful for symptomatic grading and selection at the surgical level in patients with lumbar central stenosis. A total of 263 patients (337 levels < 75 mm2 of dural cross sectional area (DCSA)) were included. The enhancement patterns of dorsal epidural vein (DVCE), periradicular vein (PVCE) and intraradicular vein (IRCE) were assessed qualitatively. The quantification of IRCE was acquired by the ratio (%) (enhancement parameters: MS/P1, MS/P2, WR/P1, WR/P2) of signal intensities between the cauda equina (MS-IRCE: maximal spot rootlet, WR-IRCE: whole rootlets) and psoas muscle (P1, P2). Receiver-operator characteristic curves were plotted to obtain imaginary cutoff values for the prediction of symptomatic appearance or operation decision. All levels were classified into seven groups on the basis of pain distribution and the presence of IRCE. PVCE was significantly related to high incidences of symptoms, unilaterality and operation. DVCE and IRCE were connected with high incidences of symptoms, bilaterality and operation. IRCE was also related to high visual analogue scale (VAS), small DCSA and high enhancement parameters. The order of the group was concordant with the degree of enhancement parameters (p = 0.000). Cutoff values of enhancement parameters for prediction were as follows: symptoms (147/123/140/121), bilaterality (165/139/157/137) and operation (164/139/159/138). Enhancement patterns and parameters could help in stratification, grading and decision-making at the surgical level.

Radiological imaging features of the salivary glands in xerostomia induced by an immune checkpoint inhibitor

The clinical features of xerostomia induced by immune checkpoint inhibitors (ICI) are similar to those of Sjögren’s syndrome (SS), whereas the immunohistological and serological features are known to differ from those of SS. However, the radiologic imaging features of salivary glands are not yet well known. We report a case of a 56-year-old male patient diagnosed with ICI-induced xerostomia. The patient underwent various imaging examinations to investigate the condition of the salivary glands, which indicated the following: (1) less specific findings on contrast-enhanced computed tomography, (2) mixed with intermediate and low signal intensity on both T1-weighted and fat-suppressed T2-weighted magnetic resonance imaging and poor “salt and pepper” appearance on magnetic resonance sialography, and (3) multiple ovoid hypoechoic areas with hyperechoic bands without acute sialadenitis on ultrasound. These radiologic imaging findings suggested remarkable lymphocyte infiltration, which could be a characteristic of ICI-induced xerostomia.

Myofibroma/myofibromatosis: MDCT and MR imaging findings in 24 patients with radiological-pathological correlation

BackgroundThe aim of this study was to characterize the radiological features of myofibroma on multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) and correlate the imaging findings with pathologic features.MethodsThe radiological findings of 24 patients with 29 myofibromas were retrospectively reviewed. All images were evaluated with emphasis on density, signal intensity, hypointense area, and enhancement, correlating these with pathologic findings.ResultsOn plain MDCT scan, 4(26.7%) tumors were homogeneous isodensity, 4(26.7%) tumors were heterogeneous hyperdensity, and 7(46.7%) tumors were heterogeneous hypodensity. On contrast-enhanced MDCT scan, all tumors (9/9) showed heterogeneous enhancement with moderate in 3(33.3%) and marked in 6(66.7%) tumors, and their enhancements were higher compared to adjacent skeletal muscle (P = 0.0001). On MRI, heterogeneous slight hyperintensity, homogeneous slight hyperintensity, and heterogeneous hypointensity on T1-weighted imaging (T1WI) were observed in 14(82.3%), 1(5.9%) and 2(11.8%) tumors, respectively. On T2-weighted imaging (T2WI) and fat-suppressed (FS) T2WI, all tumors demonstrated heterogeneous hyperintensity. All tumors showed heterogeneous marked enhancement on FS contrast-enhanced T1WI. On T1WI, T2WI, FS T2WI, and FS contrast-enhanced T1WI, irregular strip or/and patchy hypointensities were found in 16(94.1%), 12(100%), 17(100%) and 17(100%) tumors, respectively, and pseudocapsule was seen in 5(29.4%) tumors. The hypointensities and pseudocapsule on MRI were exactly corresponding to pathological interlacing collagen fibers and fibrosis. The age of the recurrent group was lower than that of the non-recurrent group (P = 0.001) and the tumors without pseudocapsule were more likely to recur than those with pseudocapsule (P = 0.034).ConclusionMyofibromas are characterized by heterogeneous density or signal intensity, with moderate or marked enhancement. The hypointensities and pseudocapsule on MRI may be helpful in diagnosis, and the absence of pseudocapsule and younger age may be risk factors for tumor recurrence.

Texture Analysis Based on Sagittal Fat-Suppression and Transverse T2-Weighted Magnetic Resonance Imaging for Determining Local Invasion of Rectal Cancer.

Background: Accurate evaluation of local invasion (T-stage) of rectal cancer is essential for treatment planning. A search of PubMed database indicated that the correlation between texture features from T2-weighted magnetic resonance imaging (T2WI) (MRI) and T-stage has not been explored extensively.Purpose: To evaluate the performance of texture analysis using sagittal fat-suppression combined with transverse T2WI for determining T-stage of rectal cancer.Methods: One hundred and seventy-four rectal cancer cases who underwent preoperative MRI were retrospectively selected and divided into high (T3/4) and low (T1/2) T-stage groups. Texture features were, respectively, extracted from sagittal fat-suppression and transverse T2WI images. Univariate and multivariate analyses were conducted to determine T-stage. Discrimination performance was assessed by receiver operating characteristic (ROC) analysis.Results: For univariate analysis, the best performance in differentiating T1/2 from T3/4 tumors was achieved from transverse T2WI, and the area under the ROC curve (AUC) was 0.740. For multivariate analysis, the logical regression model incorporating the independent predictors achieved an AUC of 0.789.Conclusions: Texture features from sagittal fat-suppression combined with transverse T2WI presented moderate association with T-stage of rectal cancer. These findings may be valuable in selecting optimum treatment strategy.

Application of Texture Analysis Based on Sagittal Fat-Suppression and Oblique Axial T2-Weighted Magnetic Resonance Imaging to Identify Lymph Node Invasion Status of Rectal Cancer.

Objective: To investigate the value of texture features derived from T2-weighted magnetic resonance imaging (T2WI) for predicting preoperative lymph node invasion (N stage) in rectal cancer.Materials and Methods: One hundred and eighty-two patients with histopathologically confirmed rectal cancer and preoperative magnetic resonance imaging were retrospectively analyzed, who were divided into high (N1-2) and low N stage (N0). Texture features were calculated from histogram, gray-level co-occurrence matrix, and gray-level run-length matrix from sagittal fat-suppression and oblique axial T2WI. Independent sample t-test or Mann-Whitney U-test were used for statistical analysis. Multivariate logistic regression analysis was conducted to build the predictive models. Predictive performance was evaluated by receiver operating characteristic (ROC) analysis.Results: Energy (ENE), entropy (ENT), information correlation (INC), long-run emphasis (LRE), and short-run low gray-level emphasis (SRLGLE) extracted from sagittal fat-suppression T2WI, and ENE, ENT, INC, low gray-level run emphasis (LGLRE), and SRLGLE from oblique axial T2WI were significantly different between stage N0 and stage N1-2 tumors. The multivariate analysis for features from sagittal fat-suppression T2WI showed that higher SRLGLE and lower ENE were independent predictors of lymph node invasion. The model reached an area under ROC curve (AUC) of 0.759. The analysis for features from oblique axial T2WI showed that higher INC and SRLGLE were independent predictors. The model achieved an AUC of 0.747. The analysis for all extracted features showed that lower ENE from sagittal fat-suppression T2WI and higher INC and SRLGLE from oblique axial T2WI were independent predictors. The model showed an AUC of 0.772.Conclusions: Texture features derived from T2WI could provide valuable information for identifying the status of lymph node invasion in rectal cancer.

Soft Tissue Sarcoma: Preoperative MRI-Based Radiomics and Machine Learning May Be Accurate Predictors of Histopathologic Grade.

OBJECTIVE. The purpose of this study was to assess the value of radiomics features for differentiating soft tissue sarcomas (STSs) of different histopathologic grades. MATERIALS AND METHODS. The T1-weighted and fat-suppressed T2-weighted MR images of 70 STSs of varying grades (35 low-grade [grades 1 and 2], 35 high-grade [grade 3]) formed the primary dataset used to train multiple machine learning algorithms for the construction of models for assigning STS grade. The models were tested with a separate validation dataset. RESULTS. Different machine learning algorithms had different strengths and weaknesses. The best classification algorithm for the prediction of STS grade had a combination of the least absolute shrinkage and selection operator feature selection method and the random forest classification algorithm (AUC, 0.9216; 95% CI, 0.8437-0.9995) in the validation set. The accuracy of the combined methods applied to the validation set was 91.43%; sensitivity, 88.24%; and specificity, 94.44%. CONCLUSION. Because of tumor heterogeneity, initial biopsy grade may be an underestimate of the final grade identified in extensive histopathologic analysis of surgical specimens. This creates an urgent need to construct an accurate preoperative approach to grading STS. This radiomics study revealed the optimal machine learning approaches for differentiating STS grades. This capability can enhance the precision of preoperative diagnosis.