Precontrast Magnetic Resonance Imaging Research Articles

Diagnostic efficacy of dynamic contrast-enhanced magnetic resonance perfusion imaging in detecting local tumor recurrence in patients with head and neck malignancies after definitive treatment.

Accurate interpretation of post-treatment imaging in head and neck malignancies poses a challenge due to treatment sequelae. Magnetic resonance (MR) perfusion helps in this scenario by evaluating the hemodynamic characteristics of lesions. This study aimed to elucidate the diagnostic efficacy of dynamic contrast-enhanced (DCE)-MR perfusion imaging in detecting recurrence in patients after they underwent definitive treatment for head and neck tumors. Thirty patients who had received definitive curative-intent treatment for histopathology-proven malignant head and neck tumors and in whom recurrent tumor was detected on precontrast MR imaging (MRI) were accrued in the study. Patients underwent DCE-MR perfusion imaging. Time to peak (TTP), relative maximum enhancement (RME), and relative washout (RWO) ratio were calculated by using time-intensity curve (TIC). The diagnostic accuracy was compared with histopathology. A cut-off value of ≥125.3 for RME showed a sensitivity of 76.2% and specificity of 66.7% for differentiating post-radiation changes and recurrence. The optimal cut-off for RWO ratio was ≥-6.24 with a sensitivity of 76.2% and specificity of 55.6%. The optimal cut-off of TTP was ≤45.8 s with a sensitivity of 61.9% and specificity of 77.8%. Diagnostic accuracies of RME, RWO, and TTP were 73.3%, 70%, and 66.7%, respectively. DCE-MRI had significant diagnostic accuracy in detecting and differentiating recurrences. TIC analysis of high-temporal resolution DCE-MRI can provide information regarding microcirculation of tumors, and hence can be considered as an imaging modality of choice for assessment of early local tumor recurrence in head and neck tumors.

Synthesizing MR Image Contrast Enhancement Using 3D High-Resolution ConvNets.

Gadolinium-based contrast agents (GBCAs) have been widely used to better visualize disease in brain magnetic resonance imaging (MRI). However, gadolinium deposition within the brain and body has raised safety concerns about the use of GBCAs. Therefore, the development of novel approaches that can decrease or even eliminate GBCA exposure while providing similar contrast information would be of significant use clinically. In this work, we present a deep learning based approach for contrast-enhanced T1 synthesis on brain tumor patients. A 3D high-resolution fully convolutional network (FCN), which maintains high resolution information through processing and aggregates multi-scale information in parallel, is designed to map pre-contrast MRI sequences to contrast-enhanced MRI sequences. Specifically, three pre-contrast MRI sequences, T1, T2 and apparent diffusion coefficient map (ADC), are utilized as inputs and the post-contrast T1 sequences are utilized as target output. To alleviate the data imbalance problem between normal tissues and the tumor regions, we introduce a local loss to improve the contribution of the tumor regions, which leads to better enhancement results on tumors. Extensive quantitative and visual assessments are performed, with our proposed model achieving a PSNR of 28.24 dB in the brain and 21.2 dB in tumor regions. Our results suggest the potential of substituting GBCAs with synthetic contrast images generated via deep learning.

Predicting the grade of meningiomas by clinical-radiological features: A comparison of precontrast and postcontrast MRI.

Postcontrast magnetic resonance imaging (MRI) is important for the differentiation between low-grade (WHO I) and high-grade (WHO II/III) meningiomas. However, nephrogenic systemic fibrosis and cerebral gadolinium deposition are major concerns for postcontrast MRI. This study aimed to develop and validate an accessible risk-scoring model for this differential diagnosis using the clinical characteristics and radiological features of precontrast MRI. From January 2019 to October 2021, a total of 231 meningioma patients (development cohort n = 137, low grade/high grade, 85/52; external validation cohort n = 94, low-grade/high-grade, 60/34) were retrospectively included. Fourteen types of demographic and radiological characteristics were evaluated by logistic regression analyses in the development cohort. The selected characteristics were applied to develop two distinguishing models using nomograms, based on full MRI and precontrast MRI. Their distinguishing performances were validated and compared using the external validation cohort. One demographic characteristic (male), three precontrast MRI features (intratumoral cystic changes, lobulated and irregular shape, and peritumoral edema), and one postcontrast MRI feature (absence of a dural tail sign) were independent predictive factors for high-grade meningiomas. The area under the receiver operating characteristic (ROC) curve (AUC) values of the two distinguishing models (precontrast-postcontrast nomogram vs. precontrast nomogram) in the development cohort were 0.919 and 0.898 and in the validation cohort were 0.922 and 0.878. DeLong's test showed no statistical difference between the AUC values of the two distinguishing models (p = 0.101). An accessible risk-scoring model based on the demographic characteristics and radiological features of precontrast MRI is sufficient to distinguish between low-grade and high-grade meningiomas, with a performance equal to that of a full MRI, based on radiological features.

Gd-EOB-DTPA Enhanced MRI Features of Liver Hemangiomatosis Coexistent with GCH.

This study aimed to clarify features of giant cavernous hemangioma (GCH) and liver hemangiomatosis, existing simultaneously on gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI). A total of 17 patients with reported hepatic hemangiomatosis between 2015 and 2017 were identified retrospectively. All our patients underwent pre-contrast MRI, triphasic (atrial, portal, venous) Gd-EOB-DTPA dynamic enhancement and hepatobiliary phase (20 minutes delayed). The location, size, morphology and signal characteristics on T1-weighted (T1WI) and T2-weighted images (T2WI), and Gd-EOB-DTPA-enhanced MRI of liver hemangiomatosis were evaluated. Hemangiomatosis involved the liver adjacent to the edge of the GCH with no normal liver tissue found in 13 cases; in the other 4 patients, a small area of normal liver tissue separated GCH from hemangiomatosis was seen. On non-contrast MRI images, hemangionmatosis presented as numerous microcystic lesions, with low signal intensity on T1WI and high signal intensity on T2WI, compared with unaffected liver. After administration of Gd-EOB-DTPA, heterogeneous enhancement was presented in the arterial phase, during portal and venous phase imaging, becoming more homogeneous. 11 cases showed hypointensity in the hepatobiliary phase (6 cases with intratumor necrosis), and 6 cases showed hyper-intensity in the hepatobiliary phase with a remaining unfilled portion. Hemangiomatosis is extremely rare in the liver adjacent to a GCH. MRI is of great diagnostic and clinical value for this kind of tumor according to the configuration, size, signal, and style of enhancement, but the final diagnosis depends on pathology. Gd-EOB-DTPA-enhanced MRI may help in diagnosing hemangiomatosis coexistent with GCH.

Semiquantitative 3T Brain Magnetic Resonance Imaging for Dynamic Visualization of the Glymphatic-Lymphatic Fluid Transport System in Humans: A Pilot Study.

Recently, a novel clearing system for interstitial solutes of the brain was described as a perivascular pathway named the glymphatic system. Furthermore, lymphatic vessels were found in the meninges to drain interstitial fluids. It is hypothesized that interstitial solutes, such as amyloid β, are firstly processed through the brain by the glymphatic system and secondly drained out of the brain by lymphatic vessels (glymphatic-lymphatic fluid transport system [GLS]). Since then, various neurological disorders, such as Alzheimer disease, have been associated with a dysfunction of the GLS. In the current study, we aimed to establish a clinical magnetic resonance imaging (MRI) study protocol for visualizing lymphatic vessels as part of the GLS in humans. More importantly, we aimed to describe the dynamic changes of a contrast agent in these lymphatic vessels over time. Twenty volunteers with an unremarkable neurological/psychiatric history were included in this 3T MRI study. Serial MRI sequence blocks were performed at 3 predefined time points (TPs): TP 1, precontrast MRI before administration of a gadolinium-based contrast agent (GBCA); TP 2, immediately post-GBCA (early ce-MRI); and TP 3, 60 minutes post-GBCA (late ce-MRI). Each MRI block contained the following sequences obtained in the same order: whole-brain 3D T1-MPRAGE, whole-brain 3D T2-FLAIR, focused 2D T2-FLAIR, and whole-brain 3D T1-SPACE. Signal intensity (SI) in compartments of the GLS adjacent to the superior sagittal sinus, gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) was calculated by manually placed regions of interest. The time course of the signal intensities was examined by generalized linear mixed models. The data were adjusted for age, cognitive function (Montreal-Cognitive-Assessment test), and sleep quality (Pittsburgh Sleep Quality Index questionnaire). The GLS was best visualized in the 2D T2-FLAIR and 3D T1-SPACE sequences, enabling further SI measurement. In precontrast (TP 1), the SI within the GLS was significantly higher than in CSF and significantly lower than in GM and WM. In post-GBCA, a significant increase (TP 2) and decrease (TP 3), respectively, of the GLS SI values were noted (86.3 ± 25.2% increase and subsequent decrease by 25.4 ± 9% in the 3D T1-SPACE sequence). The SI values of CSF, GM, and WM did not change significantly between the 3 TPs. A clinical MRI study protocol was established for the visualization of lymphatic vessels as an important part of the GLS and therefore the brain's clearing mechanism of interstitial solutes. Furthermore, dynamic changes in the GLS were described over time, possibly reflecting the clearing function of the GLS. This might constitute the basis for evaluating the GLS function in manifold neurological pathologies in the future.

Bi-directional Synthesis of Pre- and Post-contrast MRI via Guided Feature Disentanglement.

Magnetic resonance imaging (MRI) with gadolinium contrast is widely used for tissue enhancement and better identification of active lesions and tumors. Recent studies have shown that gadolinium deposition can accumulate in tissues including the brain, which raises safety concerns. Prior works have tried to synthesize post-contrast T1-weighted MRIs from pre-contrast MRIs to avoid the use of gadolinium. However, contrast and image representations are often entangled during the synthesis process, resulting in synthetic post-contrast MRIs with undesirable contrast enhancements. Moreover, the synthesis of pre-contrast MRIs from post-contrast MRIs which can be useful for volumetric analysis is rarely investigated in the literature. To tackle pre- and post- contrast MRI synthesis, we propose a BI-directional Contrast Enhancement Prediction and Synthesis (BICEPS) network that enables disentanglement of contrast and image representations via a bi-directional image-to-image translation(I2I)model. Our proposed model can perform both pre-to-post and post-to-pre contrast synthesis, and provides an interpretable synthesis process by predicting contrast enhancement maps from the learned contrast embedding. Extensive experiments on a multiple sclerosis dataset demonstrate the feasibility of applying our bidirectional synthesis and show that BICEPS outperforms current methods.

S2391 Concomitant Treatment of Secondary Lymphocytic Hypophysitis and Crohn’s Disease With Adalimumab

Introduction: Lymphocytic hypophysitis (LH) results from atrophy and fibrosis of pituitary cells secondary to lymphocyte infiltration. Patients initially present with headaches, visual changes and endocrine dysfunction. Magnetic resonance imaging (MRI) and biopsy are the gold-standards of diagnosis. LH is typically treated with high-dose glucocorticoids. Secondary LH can occur in association with systemic inflammatory disorders such as inflammatory bowel disease. We describe an unusual case of LH presenting during treatment revision of Crohn’s disease (CD) and successful treatment of both conditions with the anti-tumor necrosis factor antibody, adalimumab. Case description/methods: A 37-year-old female was diagnosed with inflammatory Crohn’s ileitis and achieved rapid remission with infliximab. Nine years later, she became a secondary nonresponder, having developed active disease with high antibody levels, and was switched to vedolizumab. Within a month, she developed diabetes insipidus and bitemporal hemianopsia with no prior neurological symptoms or headaches. An MRI with and without contrast revealed abnormal T2 enhancement involving the hypothalamus and optic tracts extending to the optic chiasm (Figure 1A). A pituitary biopsy was consistent with LH and she was treated with dexamethasone with symptom resolution in three months. She was tapered off steroids, but one month later she developed visual changes, headaches, and lactation. A repeat MRI showed new/increased T2 hyperintensities along the infundibulum, hypothalamus, optic chiasm, optic nerves and optic tract/subcortical white matter (Figure 1B). With the goal of treating both LH and CD with a single nonsteroidal therapy, vedolizumab was discontinued and she was started on a adalimumab and dexamethasone taper during induction. Five months later, she remained neurologically and digestively asymptomatic on adalimumab monotherapy and an MRI showed no abnormal enhancement of the chiasmal or hypophyseal region (Figure 1C). Discussion: Lymphocytic hypophysitis can be a primary or secondary disorder. This case highlights the importance of considering treatment options that reduce steroid burden when LH is associated with other systemic disorders. In this case, we postulate that switching treatment of CD with vedolizumab, which does not cross the blood-brain barrier, may have unmasked the development of LH. Switching to an anti-inflammatory agent such as adalimumab that does penetrate into the central nervous system lead to effective therapy of both disorders.Figure 1.: A. T1 pre-contrast and T2 post-contrast coronal MRI demonstrates abnormal T2 signal involving the hypothalamus and optic tracts extending to the optic chiasm (arrow), right greater than left, with patchy enhancement. B. Repeat T1 pre-contrast and post-contrast sagittal MRI demonstrates enlargement of the pituitary gland and infundibular stalk (arrow) with abnormal contrast enhancement. C. Five months later, post- adalimumab treatment, T1 pre-contrast and post-contrast sagittal MRI demonstrates normal physiologic contrast uptake of the hypophysis with a normal appearing infundibulum.

Precontrast Magnetic Resonance Imaging Findings and Assessment of Dynamic Contrast-Enhanced Magnetic Resonance Imaging in Low- and High-Flow Vascular Malformations

Objectives: To evaluate magnetic resonance imaging (MRI) findings in vascular malformations by assessing (1) the prevalence of phleboliths and flow voids and (2) dynamic contrast enhancement characteristics in early and delayed contrast phases. Methods: Ninety-eight patients (median age 27 years) were included. MRI analyses were performed by 2 radiologists that were blinded to clinical information. Phleboliths and flow-voids were assessed with T1 and short tau inversion recovery. Artery-lesion enhancement time (ALET) was assessed with time-resolved MRI angiography. Contrast accumulation until 15 minutes postinjection was assessed using subtraction techniques based on volumetric interpolated breath-hold examination. Standard statistical methods were applied. Results: Eighty-nine patients had low-flow malformations and 9 patients had high-flow malformations. Phleboliths were present in 13.5% of low-flow malformations, and 0% of high-flow malformations (P = .60). Flow voids were observed in 16.9% of low-flow malformations and 55.6% of high-flow malformations (P < .05). Median ALET of low-flow malformations was 9.2 seconds and of high-flow malformations (n = 8) was 0.8 seconds (P < .05). Twenty-one low-flow malformations had ALET that overlapped with ALET of high-flow malformations (≤6.3 seconds). Contrast accumulation between preinjection and 2 minutes postinjection was observed in 97.5% of low-flow malformations and 100% of high-flow malformations, whereas contrast accumulation between 2 and 15 minutes postinjection was observed in 92.6% of low-flow malformations and 62.5% of high-flow malformations (P < .05). Conclusion: Our data suggest that phleboliths are infrequent in vascular malformations and that flow voids may be unreliable markers of high-flow malformations. Both high- and low-flow malformations may present with considerable overlap regarding flow dynamics, implying vascular heterogeneity within both malformation types.

Machine learning classification of texture features of MRI breast tumor and peri-tumor of combined pre- and early treatment predicts pathologic complete response

PurposeThis study used machine learning classification of texture features from MRI of breast tumor and peri-tumor at multiple treatment time points in conjunction with molecular subtypes to predict eventual pathological complete response (PCR) to neoadjuvant chemotherapy.Materials and methodThis study employed a subset of patients (N = 166) with PCR data from the I-SPY-1 TRIAL (2002–2006). This cohort consisted of patients with stage 2 or 3 breast cancer that underwent anthracycline–cyclophosphamide and taxane treatment. Magnetic resonance imaging (MRI) was acquired pre-neoadjuvant chemotherapy, early, and mid-treatment. Texture features were extracted from post-contrast-enhanced MRI, pre- and post-contrast subtraction images, and with morphological dilation to include peri-tumoral tissue. Molecular subtypes and Ki67 were also included in the prediction model. Performance of classification models used the receiver operating characteristics curve analysis including area under the curve (AUC). Statistical analysis was done using unpaired two-tailed t-tests.ResultsMolecular subtypes alone yielded moderate prediction performance of PCR (AUC = 0.82, p = 0.07). Pre-, early, and mid-treatment data alone yielded moderate performance (AUC = 0.88, 0.72, and 0.78, p = 0.03, 0.13, 0.44, respectively). The combined pre- and early treatment data markedly improved performance (AUC = 0.96, p = 0.0003). Addition of molecular subtypes improved performance slightly for individual time points but substantially for the combined pre- and early treatment (AUC = 0.98, p = 0.0003). The optimal morphological dilation was 3–5 pixels. Subtraction of post- and pre-contrast MRI further improved performance (AUC = 0.98, p = 0.00003). Finally, among the machine-learning algorithms evaluated, the RUSBoosted Tree machine-learning method yielded the highest performance.ConclusionAI-classification of texture features from MRI of breast tumor at multiple treatment time points accurately predicts eventual PCR. Longitudinal changes in texture features and peri-tumoral features further improve PCR prediction performance. Accurate assessment of treatment efficacy early on could minimize unnecessary toxic chemotherapy and enable mid-treatment modification for patients to achieve better clinical outcomes.

Deep Learning-Based Superresolution Reconstruction for Upper Abdominal Magnetic Resonance Imaging: An Analysis of Image Quality, Diagnostic Confidence, and Lesion Conspicuity.

The aim of this study was to investigate the impact of a deep learning-based superresolution reconstruction technique for T1-weighted volume-interpolated breath-hold examination (VIBESR) on image quality in comparison with standard VIBE images (VIBESD). Between May and August 2020, a total of 46 patients with various abdominal pathologies underwent contrast-enhanced upper abdominal VIBE magnetic resonance imaging (MRI) at 1.5 T. After data acquisition, the precontrast and postcontrast T1-weighted VIBE raw data were processed by a deep learning-based prototype algorithm for deblurring and denoising the images as well as for enhancing their sharpness (VIBESR). In a randomized and blinded manner, 2 radiologists independently analyzed the image data sets using the unprocessed images VIBESD as a standard reference. Outcome measures were as follows: overall image quality, anatomic clarity of organ borders, sharpness of vessels, artifacts, noise, and diagnostic confidence. All ratings were performed on an ordinal 4-point Likert scale. If the MRI examination encompassed a hepatic lesion, the maximum diameter of the largest hepatic lesion was quantified, and lesion sharpness and conspicuity were evaluated on an ordinal 4-point Likert scale. In addition, a post hoc regression analysis for lesion evaluation was computed. Finally, interrater/intrarater agreement was analyzed. The overall image quality, anatomic clarity of organ borders, and sharpness of vessels in both precontrast and postcontrast images were rated significantly higher in VIBESR than in VIBESD (P < 0.001). Similarly, diagnostic confidence was higher in VIBESR than in VIBESD (P < 0.001). Furthermore, VIBESR images were rated to have significantly less noise and fewer artifacts in comparison with VIBESD (P < 0.001). The interreader agreement was substantial with a Cohen κ of 0.72 for the precontrast analysis and a κ of 0.74 for the postcontrast analysis. A total of 28 hepatic lesions were analyzed. For both readers, lesion sharpness and conspicuity were rated significantly better in VIBESR than in VIBESD in both the precontrast and postcontrast data sets (P < 0.01), which was consistent with the post hoc regression analysis (for every 1-point increase in sharpness/conspicuity, the odds ratio revealed a positive relation with VIBESR of 13-fold to 17-fold in comparison with VIBESD; P < 0.001). In terms of lesion size, there was no significant difference between the precontrast VIBESD and VIBESR or between the postcontrast VIBESD and VIBESR for both readers. Similarly, there was an excellent interreader agreement regarding lesion size (intraclass correlation coefficient, >0.9). The data-driven superresolution reconstruction (VIBESR) is clinically feasible for precontrast and postcontrast upper abdominal VIBE MRI, providing improved image quality, diagnostic confidence, and lesion conspicuity compared with standard VIBESD images.

Sensitivity of Pre-Contrast Multiphase versus Conventional Liver MRI in Diagnosing Hepatic Hemangioma

Hepatic hemangioma (HH) can be diagnosed noninvasively via dynamic contrast enhancement computed tomography, magnetic resonance imaging (MRI) or ultrasonography. Diagnosis HH is based on imaging features such as early arterial phase enhancement and persistence enhancement on portal or delayed phase. However, differentiating small or atypical hemangiomas from other hepatic masses using these imaging methods maybe be difficult, especially in patients with a medical history of malignant disease. Another challenge in clinical practice is when patients with acute or chronic renal insufficiency, use MRI contrast agent gadolinium (Gd) with the risk of nephrogenic systemic fibrosis. Differentiating hemangioma from its mimickers on preoperative imaging studies is of critical importance. Our study compared the diagnostic sensitivity of pre-contrast multiphase and conventional liver MRI. Total 80 patients with HH were participate to our study retrospectively. Imaging was performed using pre-contrast multiphase and conventional liver MRI methods. The size of the nodule/mass to be evaluated was ≥1 cm. All patients MRI images were obtained and classified into two groups based on the acquisition parameters. The first group with pre-contrast multiphase MRI sequences, and the second group of conventional liver MRI methods included pre-contrast multiphase MRI sequences, contrast-enhanced tri-phase sequences. The study was reviewed and analyzed by two independence gastrointestinal radiologists, who were blinded to the examination and follow-up study results. The diagnostic sensitivity was compared between pre-contrast multiphase MRI sequences only and conventional liver MRI sequences methods. Based on the observation of two gastrointestinal radiologists, our results showed mean sensitivity of 90.0% and 97.5% for pre-contrast multiphase MRI and conventional liver MRI, respectively. Pre-contrast multiphase MRI sequence methods may be reliably applied in the diagnosis of HH.

Traditional and Advanced Neuroimaging Contributions to the Diagnosis and Differential Diagnosis of Central Nervous System Lymphoma Patients Visiting a Comprehensive Medical Center

Introduction: The diagnosis of Central Nervous System Lymphoma, especially the Primary Central Nervous System Lymphoma is carried out based on brain imaging, thus avoiding an unnecessary extend of surgery. But the traditional imaging techniques, such as Computed Tomography and Magnetic Resonance Imaging, were not satisfactory. Aims: This study was conducted to characterize the spectrum of advanced Neuroimaging, such as the advanced Magnetic Resonance Imaging features in the Central Nervous System Lymphoma patients in a comprehensive medical center in Lebanon, and compare them to what has been described in the literature review. Methods: It is a retrospective exploratory study of the clinical data and imaging features for patients admitted to the emergency and radiology departments with ages above 10 years, and who were diagnosed histopathologically with intracranial lymphoma. This study may be the first to make a Radiological evaluation of Central Nervous System Lymphoma on the local population of patients over 9 years . Results: Results showed that the study of the Computed Tomography and Magnetic Resonance Imaging data of 10 immunocompetent patients with Central Nervous System Lymphoma concurs with the previously described patient populations, except for the gender parameter. Tumors were mostly presented in the fifth or Sixth decade and they could be solitary or multi-focal. Lesions were typically located Preprint submitted to The Open Neuroimaging Journal May 14, 2020 in the supratentorial compartment. On the brain Computed Tomography, the lesions were hyperdense, and in pre-contrast Magnetic Resonance images, the lesions appeared hypointense on T1 and hyperintense on T2-Weighted images, but hypointense with respect to the grey matter. The lesions were also surrounded with a mild to moderate edema as compared to other intracranial neoplasms, such as glioblastomas. Evaluation results showed that on post-contrast Magnetic Resonance images, the majority of lesions exhibited a homogeneous enhancement of 50%. Majority of the lesions also showed a less common heterogeneous ring-like enhancement of 40%, and revealed the uncommon absence of enhancement of 10%. Calcifications, hemorrhage, and necrosis were rare findings and were present in only one patient. Conclusion: As a future prospect, studying whether the advanced imaging techniques may provide not only non-invasive and morphological characteristics but also non-invasive biological characteristics and thus accurate diagnosis could be considered.

MRI of a Sertoli Cell Tumor of the Testis: A Case Report

Introduction: Sertoli cell tumors (SCTs) of the testis are relatively rare neoplasms that originate from the sex cord and interstitial stromal cells of the testis. Magnetic resonance imaging (MRI) can be used for characterization, particularly recommended when clinical and ultrasonography (US) features are indeterminate for the staging of local lesions. Scrotal MRI may also help in the imaging-based differential diagnosis of a wide range of testicular neoplasms and prevents unessential radical orchiectomy in cases of benign lesions. Accurate and early diagnosis will play a key role in keeping the viability of testicle and fertility. Case Presentation: We present the case of a 46-year-old male with a 1-year duration of a left painless testicular tumor that has had some recent enlargement. He has been admitted to the Department of Urological Surgery, Shenzhen Bao’an people’s hospital, Shenzhen, Guangdong Province, China, on Dec 2nd, 2018. Laboratory tests were within normal limits. A well-defined margin (pseudocapsule) can be found both on US and pre-contrast MRI, but organ-sparing surgery is not advocated for the suspicious malignant features, including recent enlargement, intratumoral hemorrhageand necrosis, and contrast-enhancing solid tissue with indistinct and irregular marginss on MRI. Finally, this patient proceeded with radical orchiectomy after a sufficient preoperative assessment. Conclusions: The low incidence rate of SCTs and their similar clinical features to those of other testicular tumors make their preoperative diagnosis challenging, but the identification of the tumor’s extent, morphologic information, signal component, adjacent relationship, and distant metastasis on MRI images can be vital to make a differential diagnosis, establish reasonable intervention plans, and predict the prognosis.

Identification of Naturally Occurring Cartilage Damage in the Equine Distal Interphalangeal Joint Using Low-Field Magnetic Resonance Imaging and Magnetic Resonance Arthrography.

Objectives: To describe detectable and non-detectable naturally occurring cartilage damage of the equine distal interphalangeal (DIP) joint using plain magnetic resonance (MR) imaging and gadolinium and saline MR arthrography. The second objective was to quantify the sensitivity, specificity and accuracy in detection of cartilage damage.Methods: In a pilot study, the distal limbs of two horses with confirmed osteoarthritis of the DIP joint were imaged with low-field MR. Magnetic resonance images were assessed in consensus by three observers and compared to gross pathological findings. Subsequently, a prospective analytical cross-sectional study design was created to compare pre-contrast MR imaging and saline and gadolinium MR arthrography of isolated equine distal limbs to gross observation findings. Hallmarq® low-field MR (0.27T) scans were performed prior to DIP joint injection, saline/gadolinium post-injection scans were performed at 15 min intervals for 2 h. Joints were inspected and the articular cartilage graded subjectively for cartilage damage (0–3). The presence of detectable or non-detectable cartilage damage on MR images was identified, characterized and recorded in consensus by three observers. Sensitivity, specificity and accuracy in detection of cartilage damage related to gross pathology were calculated.Results: The two clinical cases from the pilot study with confirmed osteoarthritis had full thickness cartilage defects; however, only one of these was correctly identified using low-field MRI. In the prospective study, the majority of naturally occurring cartilage damage could not be identified on plain MR or MR arthrography including extensive partial thickness cartilage erosions. Saline and gadolinium MR arthrography did not improve the detection of cartilage damage. The accuracy of cartilage damage detection was 0.63 with a sensitivity of 0.14 and specificity of 0.92.Clinical Relevance: Both, plain low-field MRI and MR arthrography are not sensitive in detection of naturally occurring cartilage damage of the DIP joint. However, if an abnormal contour is seen in the articular cartilage, cartilage damage is likely to be present.

The Human Visual Pathway Communicates Directly With the Subarachnoid Space.

Explore in vivo whether there is direct communication between the cerebrospinal fluid (CSF) and extravascular compartment of human visual pathway structures. A prospective and observational study included 10 subjects who underwent intrathecal gadolinium-enhanced magnetic resonance imaging (MRI) for suspected CSF circulation disorder, but with a negative result and with no known ophthalmic diseases. After precontrast T1-weighted MRI, 0.5 mL of gadobutrol (Gadovist, 1.0 mmol/mL) was injected intrathecally. Gadobutrol distributes in the extravascular space, and served as a CSF tracer. Consecutive MRI scans were obtained throughout 24 to 48 hours. To assess gadobutrol contrast enrichment, regions of interest (ROIs) were placed at multiple locations along the visual pathway, from the primary visual cortex to the eye's vitreous body. CSF tracer dependent T1 signal was measured in each ROI. A linear mixed-model was used for statistical analyses. CSF tracer enrichment was found within the optic nerve, optic chiasm, optic tract, and primary visual cortex (P < 0.001). Peak tracer enrichment in the visual pathway generally occurred after 24 hours and was preceded by peak enhancement in the prechiasmatic cistern after 4 to 6 hours. The results indicate direct communication between CSF of subarachnoid space and the extravascular space of the human visual pathway. Extravascular entry of the CSF tracer is a prerequisite for a glymphatic system, the present findings may suggest its presence. The existence of a glymphatic system in the human visual pathway could bring novel perspectives on the pathophysiology and treatment of ophthalmic diseases.

Radiomics-based classification of hepatocellular carcinoma and hepatic haemangioma on precontrast magnetic resonance images

BackgroundTo evaluate the feasibility of using radiomics with precontrast magnetic resonance imaging for classifying hepatocellular carcinoma (HCC) and hepatic haemangioma (HH).MethodsThis study enrolled 369 consecutive patients with 446 lesions (a total of 222 HCCs and 224 HHs). A training set was constituted by randomly selecting 80% of the samples and the remaining samples were used to test. On magnetic resonance (MR) images of HCC and HH obtained with in-phase, out-phase, T2-weighted imaging (T2WI), and diffusion-weighted imaging (DWI) sequences, we outlined the target lesions and extracted 1029 radiomics features, which were classified as first-, second-, higher-order statistics and shape features. Then, the variance threshold, select k best, and least absolute shrinkage and selection operator algorithms were explored for dimensionality reduction of the features. We used four classifiers (decision tree, random forest, K nearest neighbours, and logistic regression) to identify HCC and HH on the basis of radiomics features. Two abdominal radiologists also performed the conventional qualitative analysis for classification of HCC and HH. Diagnostic performances of radiomics and radiologists were evaluated by receiver operating characteristic (ROC) analysis.ResultsValuable radiomics features for building a radiomics signature were extracted from in-phase (n = 22), out-phase (n = 24), T2WI (n = 34) and DWI (n = 24) sequences. In comparison, the logistic regression classifier showed better predictive ability by combining four sequences. In the training set, the area under the ROC curve (AUC) was 0.86 (sensitivity: 0.76; specificity: 0.78), and in the testing set, the AUC was 0.89 (sensitivity: 0.822; specificity: 0.714). The diagnostic performance for the optimal radiomics-based combined model was significantly higher than that for the less experienced radiologist (2-years experience) (AUC = 0.702, p < 0.05), and had no statistic difference with the experienced radiologist (10-years experience) (AUC = 0.908, p>0.05).ConclusionsWe developed and validated a radiomics signature as an adjunct tool to distinguish HCC and HH by combining in-phase, out-phase, T2W, and DW MR images, which outperformed the less experienced radiologist (2-years experience), and was nearly equal to the experienced radiologist (10-years experience).

Inter-rater Variability in the Interpretation of Pre and Post Contrast MRI for Pre-Surgical Evaluation of Osteosarcoma in Long Bones in Pediatric Patients and Young Adults

Background and ObjectivesThe value of gadolinium enhanced magnetic resonance imaging (MRI) sequences for extremity osteosarcoma resection planning is unverified. We evaluate the performance of intravenous gadolinium enhanced MRI for identification of neurovascular bundle involvement (NBI) and intraarticular extension (IAE) in patients with osteosarcoma. MethodsTwo pediatric radiologists independently analyzed MRI examinations of patients with pathology proven extremity osteosarcoma for NBI and IAE. Initial evaluation utilized only non-contrast MRI images (PRE) and, after 2 weeks, subsequent evaluation included both the pre and post contrast images (POST). Cohen’s Kappa and McNemar’s test were calculated to assess agreement between PRE and POST image interpretations of NBI and IAE. Results56 patients with 90 preoperative MRI examinations were analyzed. PRE and POST interpretations were rarely discordant; 4/90 cases for NBI (Kappa 0.91) and 2/90 cases for IAE (Kappa 0.95). McNemar’s test did not show a difference between PRE and POST imaging (NBI p=0.62; IAE p=0.48). ConclusionNo significant difference between PRE and POST image interpretation was found. A high level of agreement between PRE and POST image interpretation suggests that pre-contrast MRI may be sufficient for pre-surgical planning for pediatric patients with long bone osteosarcoma.

Imaging Spectrum of TIPIC Syndrome : Validation of anew Entity with Vessel Wall Imaging.

Acute neck pain can have non-vascular and vascular causes. Some patients present with distinct vascular and perivascular changes on imaging at the site of tenderness. This study aimed to evaluate the imaging findings of transient perivascular inflammation of the carotid artery (TIPIC) syndrome with an emphasis on vessel wall imaging using 3‑Tesla (3-T) high-resolution (HR) magnetic resonance imaging (MRI). Clinical data along with diagnostic and follow-up imaging of patients presenting to these hospitals with acute neck pain/tenderness and at least 1 imaging study using color Doppler ultrasound (CDU) and/or MRI including vessel wall imaging from September 2013 through September 2017 were retrospectively evaluated. Atotal of 15 patients with no other underlying cause of pain, findings meeting the imaging criteria for TIPIC syndrome and clinical recovery (spontaneous or with treatment) were included in the study. The mean patient age was 43.2 years. With CDU and precontrast MRI, perivascular inflammation (PVI) of the involved artery segment was evident in all patients. Contrast enhancement of the adventitia and PVI were noted on postcontrast HR vessel wall MRI in all patients. Of the patients five had co-existing plaques at the site of tenderness. Follow-up imaging demonstrated pronounced regression or complete resolution of the findings. Imaging is useful for the establishment of TIPIC syndrome diagnosis and to rule out other conditions. The use of CDU is usually sufficient for diagnosis and follow-up but in clinically doubtful and complicated cases, vessel wall imaging with HR-MRI is very valuable. Thorough knowledge of this entity among radiologists enables a prompt diagnosis, which accelerates the clinical management.

Accuracy of Pre- and Postcontrast, 3 T Indirect MR Arthrography Compared with Wrist Arthroscopy in the Diagnosis of Wrist Ligament Injuries.

Background Magnetic resonance (MR) is the most important imaging technique to assess intra-articular pathology of the wrist. Among various MR imaging protocols, the diagnostic performance of indirect MR arthrography needs further investigation. Purpose The purpose of this study was to assess the diagnostic performance of pre- and postcontrast, 3 T indirect MR arthrography in the diagnosis of scapholunate intrinsic ligament (SLIL) and triangular fibrocartilage complex (TFCC) injuries, using wrist arthroscopy as reference standard. Patients and Methods We retrospectively evaluated consecutive patients with suspected SLIL or TFCC injury, who had indirect MR arthrography done before arthroscopy. Images were assessed independently by two senior radiologists. Results Arthroscopy of the 53 wrists demonstrated 16 Geissler stages II and III partial tears and 6 stage IV total SLIL ruptures. Central perforation of the TFCC was found in 24 wrists, and 12 wrists had an ulnar class 1B lesion. To detect any SLIL tear, accuracy was higher for the two observers using postcontrast indirect MR arthrography (0.77 and 0.72) than for precontrast MR imaging (0.60 and 0.60). No difference was found for total SLIL ruptures "0.85 and 0.89" versus "0.85 and 0.89." To diagnose class 1B TFCC injuries, accuracy was higher using postcontrast indirect MR arthrography (0.85 and 0.75) than for precontrast MR imaging (0.70 and 0.72). No difference in accuracy was demonstrated for TFCC central tears "0.75 and 0.75" versus "0.70 and 0.77." Conclusion Postcontrast images at 3 T indirect MR arthrography, compared with precontrast images, have an improved diagnostic performance for the overall detection of SLIL injuries and as well as class 1B TFCC tears. Level of Evidence This is a Level II, diagnostic study.

Do we need gadolinium-based contrast medium for brain magnetic resonance imaging in children?

Brain imaging is the most common examination in pediatric magnetic resonance imaging (MRI), often combined with the use of a gadolinium-based contrast medium. The application of gadolinium-based contrast medium poses some risk. There is limited evidence of the benefits of contrast medium in pediatric brain imaging. To assess the diagnostic gain of contrast-enhanced sequences in brain MRI when the unenhanced sequences are normal. We retrospectively assessed 6,683 brain MR examinations using contrast medium in children younger than 16years in the pediatric radiology department of the University Hospital Leipzig to determine whether contrast-enhanced sequences delivered additional, clinically relevant information to pre-contrast sequences. All examinations were executed using a 1.5-T or a 3-T system. In 8 of 3,003 (95% confidence interval 0.12-0.52%) unenhanced normal brain examinations, a relevant additional finding was detected when contrast medium was administered. Contrast enhancement led to a change in diagnosis in only one of these cases. Children with a normal pre-contrast brain MRI rarely benefit from contrast medium application. Comparing these results to the risks and disadvantages of a routine gadolinium application, there is substantiated numerical evidence for avoiding routine administration of gadolinium in a pre-contrast normal MRI examination.