Axial Sequences Research Articles

High diagnostic accuracy of magnetic resonance imaging in detecting subscapularis tendon tears by focusing on the most superior portion of the subscapularis tendon

This study aimed to test the hypothesis that identifying the exact location of the most superior portion of the subscapularis tendon using magnetic resonance imaging (MRI) provides high diagnostic accuracy in detecting subscapularis tendon tears. This study included 157 patients who underwent primary arthroscopic rotator cuff repair between 2014 and 2017. All patients underwent conventional 1.5-T MRI in our hospital, within 3months before surgery. We retrospectively compared the diagnosis of subscapularis tendon tears using MRI based on an anatomical concept focusing on the superior-most insertion point of the subscapularis tendon with intraoperative arthroscopic findings. Subscapularis tendon tears were detected in 80 (51.0%) of the 157 patients during arthroscopic evaluation. The overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the MRI examination were 90, 83, 85, 89, and 87%, respectively. With a kappa score of 0.83, the concordance rate between the two raters was almost perfect (95% confidence interval, 0.75-0.92). The sensitivities of the oblique-sagittal and axial sequences were 84 and 79%, respectively. Preoperative MRI evaluation focusing on the most superior portion of the subscapularis tendon demonstrated high diagnostic accuracy in detecting subscapularis tendon tears. To find the most superior portion of the subscapularis tendon tears, it was essential to check the slice at the level of the lesser tubercle tip and its adjacent slice. In addition, the combined observation of oblique-sagittal and axial sequences helped to detect subscapularis tendon tears with higher sensitivity.

Preoperative prediction and histological stratification of intracranial solitary fibrous tumours by machine-learning models

To explore the effectiveness and feasibility of machine-learning models based on magnetic resonance imaging (MRI) radiomics features in differentiating intracranial solitary fibrous tumour (ISFT) from angiomatous meningioma (AM) and stratifying ISFT histologically. This study retrospectively recruited 268 patients with a histological diagnosis of ISFT (n=120) or AM (n=148), and 116 of the ISFT patients were used for stratified analysis of histological grade. The radiomics features were extracted from axial T1-weighted imaging (WI), T2WI and contrast-enhanced T1WI sequences. All patients were assigned randomly to the training group and test group in a ratio of 7:3. The models were optimised by 10-fold cross-validation in the training group, and the independent test group was used for further testing of the models. The performances of machine-learning models based on radiomics, clinical, and fusion features in predicting and stratifying ISFT were evaluated. ISFT and AM differed significantly in terms of age, tumour shape, enhancement pattern, and margin. There was no significant difference in the clinical characteristics between World Health Organization (WHO) grade II and WHO grade III ISFT. When used to differentiate ISFT from AM, the area under the curve (AUC) values of the machine-learning models based on radiomics, clinical, and fusion features in the test group were 0.917, 0.923 and 0.950, respectively. When used for histological stratification of ISFT, the model based on the radiomics signature achieved an AUC value of 0.786 in the test group. Machine-learning models can contribute in the prediction and histological stratification of ISFT non-invasively, which can help clinical differential diagnosis and treatment decisions.

NIMG-78. DEVELOPMENT OF A PRECLINICAL GLIOBLASTOMA MURINE MODEL FOR THE ASSESSMENT OF RADIATION NECROSIS USING DIFFUSION KURTOSIS IMAGING

Abstract Glioblastoma (GB) patients often present with either radiation-induced necrosis (RN) or develop tumor recurrence (TR). Radiologically, differentiating between these two disease states is particularly difficult, especially utilizing traditional MRI techniques. Accurately distinguishing these separate states is important, as failure to do so can ultimately lead to unnecessary surgical intervention or early cessation of appropriate radiation therapy. Currently, distinction between these pathologies is made using best clinical judgement by the neuro-oncology team. Therefore, there is a need for developing novel non-invasive techniques that can reliably distinguish between radiation necrosis and tumor recurrence. Primary data was collected utilizing orthotopically transplanted GL261 mouse GB cells in a C57BL/6 mouse. Tumor induction was verified by MRI after two weeks. RN and TR were initiated using an aggressive radiation dose fractionation (12 Gy or 60 Gy). This was completed using a 4 mm radiation cone such that one portion of the tumor received 100% dose of 12 Gy or 60 Gy fraction which is sufficient to cause RN, whereas the tumor edge received only 50% of the dose, allowing for tumor recurrence. Our data demonstrated mice tumor recurrence and radiation necrosis on MRI imaging. Axial T2-weighted MRI and DKI sequence at 2 weeks following implantation demonstrated edema compatible with tumor recurrence. One week later, the T2-weighted MRI and DKI sequences demonstrated continued tumor progression. In a separate mouse with orthotopic glioblastoma implantation with high dose (60 Gy) radiation treatment, T2 imaging and DKI demonstrated areas of tumor and suspected central radiation necrosis. DKI imaging biomarkers was compared by liquid biopsy, H&E staining, and Immunohistochemistry (IHC) analysis of sacrificed mice. Our H&E staining results showed typical pathological features of GB and RN, and TR in each case. This result demonstrated that our proposed model for radiation induction was effective at achieving its goal.

Saturday, June 18, 20229:30 AM - 10:30 AM GPP06 Presentation Time: 9:30 AM: Image-Guided Cervical Cancer Brachytherapy: Summary of Consensus Recommendations from the Society for Abdominal Radiology and American Brachytherapy Society

<h3>Purpose</h3> To summarize recommendations regarding imaging guidance for cervical cancer brachytherapy implant placement from the Society of Abdominal Radiology (SAR) and American Brachytherapy Society (ABS). <h3>Materials and Methods</h3> A comprehensive literature search was conducted on PubMed for image-guided cervical cancer brachytherapy (BT) using radiography, ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). Original research studies were included for evaluation if they included sensitivity and specificity of tumor detection, complication rates, or additional quantitative imaging results directly related to brachytherapy, such as geometric distortion measurements. The literature review was evaluated by an expert panel of members from the Society for Abdominal Radiology (SAR) and American Brachytherapy Society (ABS). These data were analyzed to determine an overall level of evidence for each recommendation and the subsequent strength of each claim. <h3>Results</h3> Three-dimensional (3D) imaging is recommended for treatment planning whenever feasible due to the rate of toxicities ≥ Grade 3 decreasing from between 0-13.5% with 2D planning to 0-5.8% with 3D planning. US guidance is highly recommended for tandem selection and insertion to reduce uterine perforation rates from 2.3-34%/insertion without US-guidance to 0-1.4%/insertion with US. US-guided interstitial needle placement is feasible when post-implant 3D imaging is available for treatment planning. Post-implant CT is recommended over orthogonal radiography to reduce genitourinary and gastrointestinal complications and evaluate proper applicator positioning. Tumor visualization is optimal on T2-weighted (T2w) MRI, which also provides improved specificity for assessment of parametrial invasion. CT-based treatment planning should refer to prior MRI for high risk-clinical target volume (HR-CTV) contouring, when available. Treatment planning on MRI is highly recommended for HR-CTV delineation, and post-applicator imaging should include at minimum both a 2D sagittal T2w and 3D axial T2w fast spin echo-based sequence. <h3>Conclusions</h3> Imaging-guidance for cervical brachytherapy implant placement is now standard-of-care. 3D imaging with MRI is highly recommended for treatment planning purposes, although CT-based planning also results in fewer complications as compared to 2D planning techniques. Ultrasound is useful for applicator placement, but application to treatment planning is limited.

Association between ambulatory skills and diffusion tensor imaging of corpus callosal white matter in infants with spina bifida.

To assess brain white matter using diffusion tensor imaging (DTI) at 1 year of age in infants diagnosed with open neural tube defect (ONTD) and explore the association of DTI parameters with ambulatory skills at 30 months of age. Magnetic resonance imaging (MRI) was performed at an average of 12 months of age and included an echo planar axial DTI sequence with diffusion gradients along 20 non-collinear directions. TORTOISE software was used to correct DTI raw data for motion artifacts, and DtiStudio, DiffeoMap and RoiEditor were used for further postprocessing. DTI data were analyzed in terms of fractional anisotropy (FA), trace, radial diffusivity and axial diffusivity. These parameters reflect the integrity and maturation of white-matter motor pathways. At 30 months of age, ambulation status was evaluated by a developmental pediatrician, and infants were classified as ambulatory if they were able to walk independently with or without orthoses or as non-ambulatory if they could not. Linear mixed-effects method was used to examine the association between study outcomes and study group. Possible confounders were sought, and analyses were adjusted for age at MRI scan and ventricular size by including them in the regression model as covariates. Twenty patients with ONTD were included in this study, including three cases that underwent postnatal repair and 17 cases that underwent prenatal repair. There were five ambulatory and 15 non-ambulatory infants evaluated at a mean age of 31.5 ± 5.7 months. MRI was performed at 50.3 (2-132.4) weeks postpartum. When DTI analysis results were compared between ambulatory and non-ambulatory infants, significant differences were observed in the corpus callosum (CC). Compared with non-ambulatory infants, ambulatory infants had increased FA in the splenium (0.62 (0.48-0.75) vs 0.41 (0.34-0.49); P = 0.01, adjusted P = 0.02), genu (0.64 (0.47-0.80) vs 0.47 (0.35-0.61); P = 0.03, adjusted P = 0.004) and body (0.55 (0.45-0.65) vs 0.40 (0.35-0.46), P = 0.01, adjusted P = 0.01). Reduced trace was observed in the CC of ambulatory children at the level of the splenium (0.0027 (0.0018-0.0037) vs 0.0039 (0.0034-0.0044) mm2 /s; P = 0.04, adjusted P = 0.03) and genu (0.0029 (0.0020-0.0038) vs 0.0039 (0.0033-0.0045) mm2 /s; P = 0.04, adjusted P = 0.01). In addition, radial diffusivity was reduced in the CC of the ambulatory children at the level of the splenium (0.00057 (0.00025-0.00089) vs 0.0010 (0.00084-0.00120) mm2 /s; P = 0.02, adjusted P = 0.02) and the genu (0.00058 (0.00028-0.00088) vs 0.0010 (0.00085-0.00118) mm2 /s; P = 0.02, adjusted P = 0.02). There were no differences in axial diffusivity between ambulatory and non-ambulatory children. This study demonstrates a significant association between white matter integrity of connecting fibers of the corpus callosum, as assessed by DTI, and ambulatory skills at 30 months of age in infants with ONTD. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

PO41 Presentation Time: 4:45 PM: Initial Experience with the New Commercial Aarhus MR Compatible Hybrid Interstitial Brachytherapy Applicator in Indian Setting

<h3>Purpose -</h3> We have been using CT based intracavitary applicator in our clinic for cervical cancer. The advent of new hybrid applicator and short sequence cube MRI sequence opened up opportunity to do advanced MRI based brachytherapy in our clinic. We present the initial clinical experience of Aarhus ring and tandem MR compatible hybrid interstitial applicator with both straight and oblique needles and no ring channel (Varian may need to add TM) which was recently approved for use in a patient with bulky cervical cancer. <h3>Material and methods -</h3> A 45 years old lady, with initial diagnosis of carcinoma cervix, stage 1B3, completed External beam radiotherapy to a total dose of 45Gy in 25 Fractions, with a good clinical response, was taken up for further treatment with brachytherapy to a total dose of 28 Gy in 4 fractions. Brachytherapy was split into two applications one week apart and two treatment fractions delivered with each application, with 8 hours gap between each fraction.We used 60 degree Aarhus applicator set with Intrauterine tandem of 40 mm length and outer ring diameter of 32 mm. The Ring includes 19 guide holes for plastic interstitial needles arranged in 2 circles, 9 in inner circle for oblique needles and 10 in outer circle for straight needles.After external radiation patient underwent MRI pelvis with only T2 weighted axial and Cube sequences, which showed residual disease limited to cervix on the right side. The depth of needle insertion into the cervix was measured on MRI to be 3cms. Procedure performed under short general anaesthesia and 4 straight plastic needles through the ring were inserted with two on either side along with 4 cm central Tandem. CT and MR performed for both applications and fused. GTV-primary and HR CTV delineated on MRI, while OARs were delineated on CT. A dose of 7 Gy per fraction prescribed to HR CTV. An optimised plan was generated on eclipse treatment planning system with repeat CT planning for remaining fractions. <h3>Results -</h3> Treatment delivery went uneventful with very minimal blood loss. Average Dose per fraction received by 90 % of volume (D90) of HR CTV was 7.617 Gy and D98 of GTV primary was 10.35 Gy, delivering a total EQD2 of 89 Gy to HR CTV and at the same time delivering 115 Gy to the GTVp. OAR doses were well constrained with Bladder 2cc receiving 79.25 Gy, Rectum 2cc constrained to 53.48 Gy, sigmoid 2cc to 58.99 Gy and small bowel to 51.98 Gy. <h3>Conclusions -</h3> We successfully implemented MRI based planning with new Aarhus applicator in our clinic. Procedure was uneventful with excellent dosimetry. We will continue to use it in our clinic for patients with locally advanced cancer.

PO17: Assessment of a Prototype Gynecologic US/MR/CT Phantom for Utilization in Interstitial Brachytherapy Training

<h3>Purpose</h3> Simulation-based education has been previously demonstrated to be efficacious for teaching intracavitary (IC) brachytherapy. In principle, the success of this "hands-on" approach could be extended to interstitial (IS) and/or hybrid IC/IS brachytherapy. Yet, this education technique has not been adopted and one reason may be the shortcomings of current simulation models. Highly-desirable features which were not available in current simulation models included: non-stylized realistic anatomical representation, compatibility with image-guidance (ultrasound, CT, and/or MRI), practical material for needle placement, and commercial availability. Our work presents results from our evaluation of the physical, radiographic, and imaging characteristics of a new commercial prototype phantom designed for simulation-based education. <h3>Materials and Methods</h3> The SIM (Simulated Inanimate Models, Pittsford, NY) gynecological trainer prototype phantom was constructed based on a representative female pelvis CT imageset to provide physically realistic anatomy within a block of tissue-like material. The original CT imageset was truncated to a region of interest with dimensions of 160 × 160 × 220 mm. To provide a planning imageset, the phantom was imaged using CT with 1 mm slice reconstruction and using an axial T2 MRI sequence with 1.5 mm slice reconstruction. We assessed the anatomic dimensions of the model, physical compatibility with different hybrid applicators, and the quality of the radiographic model on imaging. After the implant was approved, a planning CT was taken, an HR-CTV was drawn, and the plan quality was evaluated. After clinical assessment, feedback was provided to the manufacturer for consideration in future designs. <h3>Results</h3> The phantom consisted of a 15 mm introitus which preceded a cylindrical air cavity with length of 75 mm and average diameter of 20 mm with irregular ridges intended to represent a vaginal canal which was capped by a pliable opening of 3 mm intended to represent an intact cervical os. Near the cervical region, the cylindrical air cavity widened from 20 to 28 mm. Proximal to the cervical os, there was a conical air cavity 80 mm in length which represented an intrauterine canal. In addition to the air cavities and tissue, the phantom was composed of three other distinct materials designed to represent bones, bladder, and rectum - each of which was distinguishable on US-, CT- and MR-based imaging. Within the phantom, an experienced physician was able to place a tandem-and-ovoid (TO) applicator with a 30 degree curved tandem, but was restricted to ovoid sizes ≤ 20 mm. To supplement the TO, the physician was able to place three IS needles to produce a realistic hybrid IC/IS implant intended to cover a hypothetical 35 × 35 × 40 mm³ HR-CTV. Coronal and sagittal views of the phantom post-implant planning CT imageset with <i>in situ</i> hybrid IC/IS equipment are shown in Figure 1. Figure 1 also contains the final plan with HR-CTV D_90% = 102% with the purple HR-CTV contour and red 100% isodose line. The primary clinical feedback provided to the manufacturer on this prototype phantom included: enlarging the vaginal canal dimensions to physically accommodate larger IC applicators; adding a visual/palpable cervical tumor to provide a target and recreate the needle-placement decision-making process. <h3>Conclusions</h3> We report the basic characteristics of a novel gynecologic phantom prototype which intended for simulation-based training. This phantom provided an anatomically-realistic "hand-on" tool composed of various materials which were each distinguishable on three modalities: US, CT, MR. Clinical feedback was provided to the manufacturer for consideration in the next generation of this phantom.

Assessment of Interfraction Change in Gross Tumor Volume of Anal Carcinoma Patients Undergoing Curative Chemoradiotherapy

<h3>Purpose/Objective(s)</h3> Radiation with concurrent chemotherapy (CRT) represents standard definitive therapy for anal cancer. CRT protocols result in excellent local control but are associated with significant acute and late morbidity. Adaptive planning techniques may allow for decrease in treatment volume and reduce toxicity. In this study, we used serial MRI scans to assess changes in gross tumor volume (GTV) during curative CRT. <h3>Materials/Methods</h3> Since 2019, we have instituted a REB-approved prospective registry study of de-escalated radiotherapy for patients undergoing CRT for anal cancer. Patients received a total dose of 45-63 Gy in 25-35 fractions with concurrent Capecitabine and a single dose of Mitomycin-C on day 1. In addition to pre-treatment (pre-tx) CT and MR simulation, patients also underwent MR simulation at fraction 11 (fx11) and fraction 21 (fx21). The GTV was contoured separately on individual axial T2 sequences. Median (inter-quartile-range) was used for descriptive statistics and the Mann-Whitney-Wilcoxon was used between groups of interfractional contours to determine statistically significant differences in tumor size between fractions. The Kruskal-Wallace test was used to determine significance between all 3 GTV volumes. P-values of <0.05 were considered statistically significant. <h3>Results</h3> A total of 24 patients were accrued. All patient completed RT without interruptions. All 24 had pre-tx MRI. During CRT course, 22 had a second MRI scan (fx11), and 19 had a third (fx21) scan. Table 1 shows the median (IQR) pre-tx GTV and the absolute and percent reduction in the GTV at fx11 and fx21 compared to pre-treatment GTV. Median (IQR) reduction in GTV between pre-tx and fx11 and fx21 MRI was 6.1cc (3.8-12.1) and 7.8cc (5.7-14.6), respectively. Median reduction in GTV between fx11 and fx21 was 2.9cc (1.3-6.6). After normalizing volumes as the percentage of pre-tx GTV, median (IQR) volume was 62.5% (51.6-69.7) (p<0.001) at fx11 and 43.6% (34.2-55.6) (p<0.001) at fx21. Based on Kruskal-Wallace test, overall change between GTVs at all 3 time points was found to be significant, p=0.042. <h3>Conclusion</h3> For patients undergoing CRT for anal cancer, there appears to be an early and significant reduction in the tumor volume over time. This study helps define planning adaptation parameters using serial MRI during CRT and will inform strategies to reduce normal tissue exposure

Clinical and Radiomics-Based Deep Learning Predictive Model for Early Treatment Failure after Neoadjuvant Radiochemotherapy for Rectal Cancer

<h3>Purpose/Objective(s)</h3> As shown in RAPIDO and PRODIGE-23 trials, total neoadjuvant therapy for rectal cancer increases the complete response rate, however, the overall survival benefit remains uncertain. Although postponing surgery assures more time for tumor downstaging, it also increases surgical complications and can worsen prognosis in non-responding tumors. We aimed to develop a clinical and radiomics-based model for early treatment failure (ETF) prediction after neoadjuvant radiochemotherapy (RCHTx) for rectal cancer. <h3>Materials/Methods</h3> We conducted a prospective cohort analysis of 92 consecutive and eligible patients with rectal adenocarcinoma treated with neoadjuvant radiochemotherapy in the years 2018-2020, and followed until February 2022. We defined ETF as postoperative poor pathological response and no MRI-confirmed downstaging; or unresectability after neoadjuvant treatment; or cancer-related or treatment-related death within 18 months since treatment initiation. Collected clinical data included physical examination, grading, staging (before and after RCHTx), biomarker levels, RCHTx prescription details, and pre-operative MRI tumor and nodal characteristics. Radiomic features were extracted from GTV delineated on axial MRI T2 TSE sequences. To develop a predictive model, we followed OmicSelector-based (https://biostat.umed.pl/OmicSelector) feature selection, logistic regression (LR), and artificial deep neural network model development procedure. After splitting into training (60%), testing (20%), and validation (20%) datasets, the final feature set was selected based on the highest average logistic regression accuracy on all sets, while all patients with MRI performed outside our institution were included in the testing set (compensating possible batch effect). <h3>Results</h3> ETF was experienced by 24% of patients and was associated with significantly shorter overall survival (median 12.1 months [95%CI:8.5-16.5] vs. not reached, p<0.0001). None of the clinical factors was significantly associated with ETF (adjusted p value>0.05; AUC ROC range 0.39-0.64). LR model based on clinical factors presented overfitting (accuracy 82% on the training set, 56.2% on testing and 68.8% on validation set). The best feature set included 14 selected radiomic features, patient's weight, T-stage, grading, mesorectal fascia and nodal involvement. LR model based on those features achieved perfect accuracy on training and testing sets and 81.3% accuracy on the validation set. Deep neural network model utilizing selected clinical and radiomic features achieved 87.5% accuracy (80% sensitivity, 91% specificity) on testing and 93.8% accuracy (100% sensitivity, 91% specificity) on validation set. <h3>Conclusion</h3> Combined clinical and radiomics-based deep learning model could predict ETF after RCHTx for rectal cancer with at least 80% sensitivity and 90% specificity. Prediction of ETF after RCHTx could select high-risk patients who may require non-standard treatment.

Extra-articular findings in patients with suspected labral tear and value of screening pelvis sequence

Objectives: There are multiple etiologies of hip pain, of which labral tear is one of the most common in young adults which may be difficult to distinguish on history and clinical examination. Labral tears can be diagnosed using high-resolution non-contrast magnetic resonance imaging (MRI) or MR arthrogram that involves imaging the concerned hip. At our institute, we perform an additional proton density fat saturated axial sequence of the pelvis to screen for alternative pathology and we investigate the value of this in this study. Material and Methods: A retrospective review of high-resolution non-arthrographic 3T MR of hips that were referred from young adult hip services with a history of hip or groin pain and the clinical suspicion of a labral tear over 2 years was performed. Those &lt;50 years were included in the study. Results: Of 648 patients with suspected labral tears, 18% showed evidence of extra-articular hip pathologies (sacroiliac joint pathology, iliopsoas pathology, and ischiofemoral impingement) on MRI. This study has shown that approximately one in five patients with a clinically suspected labral tear showed radiological evidence of extra-articular hip pathology (sacroiliac joint pathology, iliopsoas pathology, ischiofemoral impingement, and hamstring pathology). There is therefore the potential for misdiagnosis and increased morbidity if these alternative diagnoses were not appreciated. Conclusion: A high-resolution hip MRI protocol for suspected labral tears of the hip joint should include at least one sequence of the entire pelvis to evaluate for extra-articular findings.

Ultrafast lumbar spine MRI protocol using deep learning-based reconstruction: diagnostic equivalence to a conventional protocol.

To evaluate the diagnostic equivalency between an ultrafast (1min 53s) lumbar MRI protocol using deep learning-based reconstruction and a conventional lumbar MRI protocol (12min 31s). This study included 58 patients who underwent lumbar MRI using both conventional and ultrafast protocols, including sagittal T1-weighted, T2-weighted, short-TI inversion recovery, and axial T2-weighted sequences. Compared with the conventional protocol, the ultrafast protocol shortened the acquisition time to approximately one-sixth. To compensate for the decreased signal-to-noise ratio caused by the acceleration, deep learning-based reconstruction was applied. Three neuroradiologists graded degenerative changes and analyzed for presence of other pathologies. For the grading of degenerative changes, interprotocol intrareader agreement was assessed using kappa statics. Interchangeability between the two protocols was also tested by calculating the individual equivalence index between the intraprotocol interreader agreement and interprotocol interreader agreement. For the detection of other pathologies, interprotocol intrareader agreement was assessed. For the grading of degenerative changes, the kappa values for interprotocol intrareader agreement of all three readers ranged from 0.707 to 0.804, indicating substantial to almost perfect agreement. Except for foraminal stenosis and disc contour on axial images, the 95% confidence interval of the individual equivalence index was < 5%, indicating the two protocols were interchangeable. For the detection of other pathologies, the interprotocol intrareader agreement rates were > 98% for each individual pathology. Our proposed ultrafast lumbar spine MRI protocol provided almost equivalent diagnostic results to that of the conventional protocol, except for some degenerative changes.

Geochemical study of the Ashele Copper-Zinc Deposit using portable X-ray fluorescence spectrometry based on matrix effect correction, Northwest China

Because the Ashele Cu–Zn deposit is located deep below and core samples are difficult to obtain, portable X-ray fluorescence spectroscopy (pXRF), which can be used for rapid and non-destructive analysis in the field, was chosen as the testing instrument. However, the testing accuracy and precision of elements are significantly affected by matrix effects. In this study, 170 samples from the deposit were measured, and the data was corrected using the matrix effect correction (MEC) method instead of the simple linear regression (SLR) method to enhance the data quality, followed by geochemical and correspondence analysis of the data. The results show that calibration data corrected by the MEC method was of greater quality than those corrected by the SLR method, particularly for elements such as Co, Cr, Mo, Sn, Ba, and W. The Ashele Cu–Zn deposit is formed in multi-phase hydrothermal superposition mineralization and is rich in Mg, Fe, and S but deficient in Al, Si, K, and Ca. The main mineralized zones are located at 400–500 m and 200–300 m. Cu, Zn, and Pb are significantly enriched in the mineralization, with the axial zoning sequence of the primary halo (Pb–Zn–Mn–As–Cu–Cd–Sn–Ba–Bi–Sb–Co–W–Mo) showing inverse zoning. The correspondence analysis results also show a clear distinction between non-metallogenesis and metallogenesis. Also, the application of pXRF based on MEC in the Ashele Cu–Zn deposit is effective and can be extended to other types of deposit studies.

Value and imaging findings of the magnetic resonance in the posterolateral corner complex injuries of the knee

BackgroundMRI is considered the key tool for evaluation of knee injuries, notably the posterolateral corner, due to its complexity and multi-ligament involvement. This prospective study was conducted from September 2020 to September 2021 aiming to clarify the value and possible MRI findings in assessing the posterolateral corner (PLC) knee injuries which can subsequently result in an improvement in the management of these cases, preventing devastating consequences.ResultsThe current study was conducted on 30 patients (11 females and 19 males) whose mean age was 42 years. Imaging by a closed magnet (1.5 T) MRI was applied to 30 patients with traumatic history to the knee using: axial, sagittal, coronal T1WI, T2WI, and proton density fat sat sequences. The lateral collateral ligament (LCL) was the most commonly affected ligament. Grade I injuries were the most common form of injuries. Twenty-four (80%) patients suffered from LCL injury, popliteal complex injuries were in 21 (70%) patients, 10 (33.3%) patients had biceps femoris tendon injury, while injury to the popliteofibular ligament was seen in 8 (26%) patients. The arcuate ligament was poorly defined in 6 (20%) patients, indicating that it had torn, lateral head of gastrocnemius injury was seen in 5 (16.7%) patients and 4 (13.3%) patients showed injury to the iliotibial band. Correlation with arthroscopic findings was considered the gold standard of the results whenever available. That was applied to 16 cases who had clinically significant knee injuries and arthroscopy was requested.ConclusionsMRI is a key tool for determining a correct pre-surgical evaluation and diagnosis. It is critical to have a thorough understanding of the radiological PLC anatomy, as well as the presence of various pathologies on MRI. It allows the determination of whether the tendons and ligaments are partially or completely torn, besides any related injuries preventing possible poor consequences after the restoration of the cruciate ligaments.

Three-dimensional volume rendering for dynamic characteristics of secundum atrial septal defect during various phases of the cardiac cycle and the impact on occluder selection

Objective: To investigate the dynamic change of the secundum atrial septal defect (ASD) throughout the cardiac cycle, and assess its impact on occluder selection. Methods: This study retrospectively analyzed 35 patients with ASD who received electrocardiogram-gated coronary CT angiography (CCTA) throughout the cardiac cycle as well as interventional closure therapy in Fuwai Hospital from December 2016 to December 2019. The raw data were reconstructed into 20 phasic images of RR intervals (RRI) ranging from 0 to 95% in an increment of 5% and transmitted to a workstation for postprocessing. For each phase image, CT virtual endoscopy reconstruction technique (CTVE) was used to provide views of ASD. Axial sequence assisted CT volumetric measurement (CTAS) was used to calculate the maximum dimensions in axial planes (Da) and in superior-inferior direction (Db). Using a formula for converting circumference to diameter, the equivalent circle dimensions were calculated (De, De=minor axis+2 (major axis-minor axis)/3). Taking the data of 75% RRI phase, the patients were divided into Da75%RRI≥Db75%RRI group and Da75%RRI<Db75%RR group. According to the postoperative chest X-ray, the waist diameter of the occluder in the left anterior oblique plain film was measured, and its correction value (CR-PODlaoc) was calculated with the correction formula. Scatter plots of the changes of the mean values of Da, Db and De with the cardiac cycle were presented. The change and ratio of measured values of Da and De at 35% and 75% RRI was calculated. The ratio of De change to Da change in Da75%RRI≥Db75%RRI group and Da75%RRI<Db75%RR group was calculated, respectively, and compared between groups. Pearson correlation analysis was used to explore the correlation between CR-PODlaoc and De35%RRI and De75%RRI. Results: A total of 35 patients, aged (42.7±15.0) years, including 10 males, were included. Among 35 patients, 8 cases were divided into group Da75%RRI≥Db75%RRI and 27 cases into group Da75%RRI<Db75%RRI. Both Da and Db regularly changed at each phase throughout the cardiac cycle. The Da changed significantly, with a maximum at phase of 35%-45% of RRI, and a minimum between phases of 90% and 0 of RRI. While the Db showed insignificant changes during phases of 10%-90% RRI, and increased at 0-10% of RRI, then reduced in the remaining phases. The change of Da was (6.35±2.46) mm, and the ratio of Da values at 35% and 75% RRI was 0.77±0.08. The change of De was (2.28±1.32) mm, and the ratio of De at 35% and 75% RRI was 0.93±0.05. The ratio of De change to Da change in the Da75%RRI≥Db75%RRI group was 0.67±0.13; while the ratio was 0.34±0.05 in Da75%RRI<Db75%RR group, and there was significant difference between the two groups (P=0.02). CR-PODlaoc was positively correlated with De35% RRI (r=0.99, P<0.001) and De75% RRI (r=0.98, P<0.001). Conclusions: Most secundum ASDs show oval shape with Db>Da. Db is basically constant while Da changes significantly during cardiac cycle (10%-90% RRI). Nonetheless, both values peak and maintain the maximum status at end-systolic phase (35%-45% RRI). For patients with huge ASD, occluder selection should be based on the De at 35% RRI phase, which is helpful for the successful intervention.

Structural association between heterotopia and cortical lesions visualised with 7 T MRI in patients with focal epilepsy

PurposeTo analyze structural characteristics of malformations of cortical development (MCD) at 7T and 3T MRI. MethodsTwenty-five patients were examined with a 7T MRI-scanner in addition to 3T examinations performed for epilepsy evaluation. 7T sequences included a 3D-T1-weighted (T1w) MPRAGE, 3D-T2w FLAIR, and heavily T2w axial and coronal high-resolution (0.5 × 0.5 × 0.75–1.0 mm3) 2D-TSE sequences. Images were reviewed for 7T MRI imaging characteristics of MCD, visibility and frequency of identified lesions on 7T and on 3T (original reports and second reading). ResultsIn 25 patients 112 lesions were identified (57 gray matter (GM) heterotopia, 37 focal cortical dysplasia (FCD), and 18 other MCD). Imaging characteristics of the 37 FCD were cortical thickening (n = 11); GM-WM border blurring (n = 30); GM signal intensity changes (n = 18); juxtacortical WM signal intensity changes (n = 18); and transmantle WM signal intensity changes (n = 11). None of the 7T MRI sequences was sufficient to detect all types of lesions. Heterotopia were in general isointense to normal GM. Structural associations between 36 heterotopia and overlaying cortex were observed, composed either of a direct connection, vessel-like structures, or GM-like bridges.FCD were mentioned in 30% (11 of 37) of the original reports at 3T, and in 57% (21 of 37) after second reading. FCD connections to subcortical heterotopia were clinically not reported at all. Conclusion7T MRI revealed subtle connections between heterotopia and previous unidentified pathology in overlaying cortex. These findings may be significant for the understanding of the anatomical seizure origin and propagation pathways.

The Central Sulcus of the Insula: A Highly Reliable Radiographic Landmark for Identification of the Rolandic Sulcus

Anatomic studies have suggested that the central insular sulcus (CIS) runs in line with the Rolandic sulcus (RS). The radiographic relationship between the RS and CIS has not been systematically studied. This study aims to evaluate the applicability of using the CIS as a radiologic landmark to identify the RS. We retrospectively reviewed 100 consecutive normal magnetic resonance imaging (MRI) scans (200 hemispheres) performed at a single institution. MRI scans with any intracranial pathology or finding were excluded. Sagittal and axial fluid-attenuated inversion recovery sequences were used in this study. Two evaluators independently evaluated the relationship of the CIS and RS in all MRI scans. A predefined 3-step method was then used to identify the CIS, RS, and hand motor area in sagittal and axial images. The CIS was found to be correlated with the RS in 191 hemispheres (95.5%). In the remaining 9 hemispheres, the postcentral sulcus represented the most correlated sulcus with the CIS (7 hemispheres). The interrater agreement was 0.673 (P < 0.05), indicating a substantial agreement. The hand motor area was identified in the same section as the CIS in 175 hemispheres (87.5%). The CIS is a highly reliable radiographic landmark for the identification of the RS. The hand motor area can also be identified reliably using this method.

Whole-body MRI in oncology: can a single anatomic T2 Dixon sequence replace the combination of T1 and STIR sequences to detect skeletal metastasis and myeloma?

ObjectivesTo compare the diagnostic accuracy of a single T2 Dixon sequence to the combination T1+STIR as anatomical sequences used for detecting tumoral bone marrow lesions in whole-body MRI (WB-MRI) examinations.MethodsBetween January 2019 and January 2020, seventy-two consecutive patients (55 men, 17 women, median age = 66 years) with solid (prostate, breast, neuroendocrine) cancers at high risk of metastasis or proven multiple myeloma (MM) prospectively underwent a WB-MRI examination including coronal T1, STIR, T2 Dixon and axial diffusion-weighted imaging sequences. Two radiologists independently assessed the combination of T1+STIR sequences and the fat+water reconstructions from the T2 Dixon sequence. The reference standard was established by consensus reading of WB-MRI and concurrent imaging available at baseline and at 6 months. Repeatability and reproducibility of MRI scores (presence and semi-quantitative count of lesions), image quality (SNR: signal-to-noise, CNR: contrast-to-noise, CRR: contrast-to-reference ratios), and diagnostic characteristics (Se: sensitivity, Sp: specificity, Acc: accuracy) were assessed per-skeletal region and per-patient.ResultsRepeatability and reproducibility were at least good regardless of the score, region, and protocol (0.67 ≤ AC1 ≤ 0.98). CRR was higher on T2 Dixon fat compared to T1 (p < 0.0001) and on T2 Dixon water compared to STIR (p = 0.0128). In the per-patient analysis, Acc of the T2 Dixon fat+water was higher than that of T1+STIR for the senior reader (Acc = +0.027 [+0.025; +0.029], p < 0.0001) and lower for the junior reader (Acc = −0.029 [−0.031; −0.027], p < 0.0001).ConclusionsA single T2 Dixon sequence with fat+water reconstructions offers similar reproducibility and diagnostic accuracy as the recommended combination of T1+STIR sequences and can be used for skeletal screening in oncology, allowing significant time-saving.Key Points• Replacement of the standard anatomic T1 + STIR WB-MRI protocol by a single T2 Dixon sequence drastically shortens the examination time without loss of diagnostic accuracy.• A protocol based on fat + water reconstructions from a single T2 Dixon sequence offers similar inter-reader agreement and a higher contrast-to-reference ratio for detecting lesions compared to the standard T1 + STIR protocol.• Differences in the accuracy between the two protocols are marginal (+ 3% in favor of the T2 Dixon with the senior reader; −3% against the T2 Dixon with the junior reader).

Evaluation of systematic prostate biopsies when performing transperineal MRI/TRUS fusion biopsy with needle tracking-what is the additional value?

To evaluate the additional value of systematic biopsies (SB) when performing transperineal MRI/TRUS fusion biopsies (MRI/TRUS TPBx) with needle tracking. From January 2019 to March 2021 969 Patients after a MRI/TRUS TPBx were evaluated separately for target biopsies (TB) and systematic biopsies regarding PCa detection and PCa risk evaluation. Needle tracking in the axial sequences of multiparametric MRI was used to assess the localisation of the detected PCa in the biopsy cores related to the reported PI-RADS lesions. The overall cancer detection rate (CDR) for PCa and clinically significant (cs) PCa (ISUP ≥2) with the combination of TB and SB were 66 and 49%. TB detected 46% csPCa and SB 22% csPCa. SB identified 1.5% additional csPCa outside of the reported PI-RADS lesions. 16 patients (1.7%) showed a relevant upgrading from clinically insignificant PCa in TB to csPCa. In 736 patients with unilateral suspicious lesions on MRI, 145 patients (20%) were detected with contralateral PCa-positive SB. 238 patients (25%) showed PCa positive systematic biopsy cores outside of the described PI-RADS lesions. Needle tracking optimizes the 3D-localisation of cancer in the prostate. Our results show that the added value of SB with a reduced systematic biopsy scheme is low with regard to prostate cancer (PCa) detection and PCa risk evaluation. However, there is a relevant added value for localizing multifocal PCa in the primary diagnostic by a MRI/TRUS fusion biopsy of the prostate.

Flow volume measurement of arterial venous and cerebrospinal fluid in patients with multiple sclerosis.

Multiple sclerosis (MS) is usually described as an autoimmune disease, although the exact mechanism of the disease remains unknown. There have been studies reporting that venous flow abnormalities may be involved in the pathogenesis of MS or many of the associated clinical manifestations. The aim of this study was to evaluate flow volumes of the middle cerebral artery (MCA), transverse sinus (TS), and cerebral aqueduct using phase contrast magnetic resonance imaging (PC-MRI) in relapsing-remitting MS patients and a control group. We included 34 patients diagnosed by the McDonald criteria, revised in 2017, as well as 15 healthy controls matched by age and sex. The MRI scans were performed using a 1.5-T superconducting scanner. Axial T1-weighted, T2-weighted, and PC-MRI sequences were performed for the quantitative investigation of flow volume measurements. Quantitative analyses of flows were performed using flow analyses program PC-MRI angiography software. A circular region of interest was placed manually into the cerebral aqueduct, bilateral MCA, and TS. Flow volumes of the cerebral aqueduct and MCA were not statistically significant between the MS and control groups. The flow volumes of the TS for the patient group were lower than those of the control group, and this difference was statistically significant. A reduced TS flow volume in MS patients was noted in the present study when compared with the control group, suggesting a relation between venous pathologies and MS. Further studies are needed to understand whether this relation is causal or epiphenomenal.

Effect of Preoperative MRI Coracoid Dimensions on Postoperative Outcomes of Latarjet Treatment for Anterior Shoulder Instability.

Background:Preoperative coracoid dimensions may affect the size of the bone graft transferred to the glenoid rim and thus the postoperative outcomes of Latarjet coracoid transfer.Purpose:To determine the effect of coracoid length and width as measured on preoperative magnetic resonance imaging (MRI) on outcomes after Latarjet treatment of anterior shoulder instability.Study Design:Cohort study; Level of evidence, 3.Methods:Included were patients who underwent primary Latarjet surgery between 2009 and 2019 and had preoperative MRI scans and minimum 2-year postoperative outcomes. Longitudinal coracoid length was measured on axial MRI sequences as the distance from the coracoclavicular ligament insertion to the distal tip. Comparisons were made between shorter and longer coracoids and between narrower and wider coracoids. The outcomes of interest were recurrent instability, reoperation, complications, return to sport (RTS), and American Shoulder and Elbow Surgeons (ASES) score. Independent-samples t test, Mann-Whitney test, chi-square test, and Fisher exact test were used to compare outcomes between groups, and univariate correlation coefficients were calculated to evaluate the relationships between demographics and coracoid dimensions.Results:Overall, 56 patients were included (mean age, 28.4 years). The mean ± SD coracoid length was 21.6 ± 2.4 mm and width 10.0 ± 1.0 mm. Relative to patients with a longer coracoid (≥22 mm; n = 26), patients with a shorter coracoid (<22 mm; n = 30) had similar rates of recurrent instability (shorter vs longer; 6.7% vs 3.8%), complications (10.0% vs 15.4%), reoperation (3.3% vs 7.7%), and RTS (76.5% vs 58.8%) and similar postoperative ASES scores (85.0 vs 81.6) (P ≥ .05 for all). Likewise, relative to patients with a wider coracoid (≥10 mm; n = 27), patients with a narrower coracoid (<10 mm; n = 29) had similar prevalences of recurrent instability (narrower vs wider; 6.9% vs 3.7%), complications (17.2% vs 7.4%), reoperation (3.5% vs 7.4%), and RTS (66.7% vs 68.4%) and similar postoperative ASES scores (87.1 vs 80.0) (P ≥ .05 for all).Conclusion:Patients undergoing Latarjet coracoid transfer had similar postoperative outcomes regardless of preoperative coracoid dimensions. These findings should be confirmed in a larger cohort before further clinical recommendations are made.