Minimizing neurovascular complications during image-guided percutaneous cryoablation of a cervical spinal aneurysmal bone cyst using protective doxycycline sclerotherapy: a case report.

Background: Aneurysmal bone cysts (ABC) are rare, locally aggressive bone tumors primarily observed in pediatric patients. Surgical curettage is the treatment of choice. Image-guided percutaneous cryoablation (CYOA) is a recently implemented alternative technique in cases not amenable to surgery. CYOA may be limited if the lesion is close to critical neurovascular structures. In this case report, a cervical spinal ABC was successfully treated using CYOA in combination with complementary and protective image-guided percutaneous doxycycline sclerotherapy (DS) to dissect and treat the portion of the lesion in contact with critical structures. Case Description: A 4-year-old male presented with a symptomatic ABC within the C5 vertebral body, which encompassed the right vertebral artery and contacted the right C5-C6 spinal cord and nerve roots. After ruling out surgery due to the proximity of critical neurovascular structures, treatment with CYOA was performed. However, subsequent follow-up showed recurrence in the part of the lesion contacting critical structures. A second approach was then decided, using DS to dissect and treat the most vulnerable portion and CYOA to treat the remaining tumor. Follow-up showed almost complete sclerosis of the lesion and total resolution of symptoms 3 years after treatment. Conclusions: Using DS to dissect and treat the portion of the lesion in contact with critical neurovascular structures during CYOA treatment of a cervical spinal ABC allowed for a safe and effective approach in our case.

Reliability assessment of the OMERACT whole-body magnetic resonance imaging scoring system for juvenile idiopathic arthritis.

Inter-reader reliability of a new scoring system for evaluating joint inflammation and enthesitis in whole body MRI (WBMRI) in juvenile idiopathic arthritis was tested. The scoring system grades 732 item-region combinations of bone marrow and soft tissue changes for commonly involved joints and entheseal sites. Five radiologists rated 17 WBMRI scans through an online rating platform. Item-wise reliability was calculated for 117 items with non-zero scores in >10 % of readings. Interquartile ranges of the five-reader Kappa reliability coefficients were 0.58-0.73 (range: 0.36-0.88) for the joints, 0.65-0.81 (range: 0.39-0.95) for the entheses, and 0.62-0.75 (range: 0.60-0.76) for chronic nonbacterial osteomyelitis-like lesions.

Bacterial osteomyelitis in pediatric patients: a comprehensive review.

Bacterial osteomyelitis, an inflammatory response in the bone caused by microorganisms, typically affects the metaphysis in the skeletally immature. Bacterial osteomyelitis possesses a significant diagnostic challenge in pediatric patients due to its nonspecific clinical presentation. Because the metaphysis is the primary focus of infection in skeletally immature patients, understanding the normal physiologic, maturation process of bones throughout childhood allows to understand the pathophysiology of osteomyelitis. Timely and accurate diagnosis is crucial to initiate appropriate treatment, and prevent long-term sequelae and efforts must be made to isolate the causative organism. The potential causative organism changes according to the age of the patient and underlying medical conditions. Staphylococcus Aureus is the most common isolated bacteria in pediatric pyogenic osteomyelitis whereas Kingella Kingae is the most common causative agent in children aged 6 months to 4 years. Imaging plays a pivotal role in the diagnosis, characterization, evaluation of complications, and follow up of bacterial osteomyelitis. Imaging also plays a pivotal role in the evaluation of potential neoplastic and non-neoplastic mimickers of osteomyelitis. In children, MRI is currently the gold standard imaging modality when suspecting bacterial osteomyelitis, whereas surgical intervention may be required in order to isolate the microorganism, treat complications, and exclude mimickers.

Radiologic and Clinical Features of Infantile Hemangioma: Potential Pitfalls and Differential Diagnosis.

Infantile hemangioma (IH) is the most common neoplasm in children, but it may mimic other types of vascular anomalies or nonvascular benign and malignant tumors. In most cases, the clinical appearance, time of onset, and pattern of involution facilitate its diagnosis. Imaging evaluation is not always needed since the IH features at clinical presentation are usually characteristic, but when needed, US and frequently MRI are the imaging modalities of choice. Clinical photography or photographic documentation plays a central role in monitoring these lesions over their clinical course. Photographic documentation can also add confidence and alert the radiologist when interpreting imaging studies. Some vascular anomalies, especially vascular malformations, are a frequent source of confusion, as these may resemble IHs clinically and at imaging. The lack of uniform terminology also hinders an accurate diagnosis. To unify the terminology and minimize confusion, the International Society for the Study of Vascular Anomalies created a helpful classification in 1994. In addition, radiologists need to be aware of and become familiar with other neoplasms in children that may resemble IH to avoid misdiagnosis and unnecessary procedures. Fibrous and lipomatous tumors are examples of benign tumors that can mimic IHs clinically and at imaging, whereas rhabdomyosarcoma, infantile fibrosarcoma, neuroblastoma, and lymphoproliferative disorders are examples of malignant neoplasms. The authors review the features of IH at clinical presentation and imaging evaluation, highlighting its different phases of evolution and stressing the importance of photographic documentation. The authors also review pitfalls of IH with helpful pearls for differentiation. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material. See the invited commentary by Khanna and Briones in this issue.

Sono-Elastography: An Ultrasound Quantitative Non-Invasive Measurement to Guide Bacterial Pneumonia Diagnosis in Children.

Lung ultrasound (LUS) is, at present, a standard technique for the diagnosis of acute lower respiratory tract infections (ALRTI) and other lung pathologies. Its protocolised use has replaced chest radiography and has led to a drastic reduction in radiation exposure in children. Despite its undeniable usefulness, there are situations in which certain quantitative measurements could provide additional data to differentiate the etiology of some pulmonary processes and thus adapt the treatment. Our research group hypothesises that several lung processes such pneumonia may lead to altered lung tissue stiffness, which could be quantified with new diagnostic tests such as lung sono-elastography (SE). An exhaustive review of the literature has been carried out, concluding that the role of SE for the study of pulmonary processes is currently scarce and poorly studied, particularly in pediatrics. The aim of this review is to provide an overview of the technical aspects of SE and to explore its potential usefulness as a non-invasive diagnostic technique for ALRTI in children by implementing an institutional image acquisition protocol.

Ankle and Foot Deformities in Children.

Ankle and foot deformity is one of the most common musculoskeletal disorders in children and a leading cause of functional impairment and diminished quality of life when not treated. A spectrum of conditions may produce foot and ankle deformities, with congenital disorders the most frequent cause, followed by acquired conditions. Congenital disorders include congenital talipes equinovarus or congenital clubfoot, metatarsus adductus, skewfoot, congenital vertical talus, and tarsal coalition.Some of these deformities are frequent and easily diagnosed based on clinical features, but clinical overlap between pathologies can be challenging. Thus imaging plays a paramount role in evaluating these patients. Radiographs are the first imaging modality of choice, but they may not be sufficient in infants due to the lack of ossification of the tarsal bones. Ultrasonography allows not only a detailed visualization of the cartilaginous structures but also permits a dynamic study of the foot and ankle. Computed tomography may be necessary in certain conditions such as tarsal coalitions.

Determination of Relative Weightings for Sacroiliac Joint Pathologies in the OMERACT Juvenile Arthritis Magnetic Resonance Imaging Sacroiliac Joint Score.

This study aims to determine the relative weights (point value) of items of the juvenile idiopathic arthritis magnetic resonance imaging-sacroiliac joint scoring system (JAMRIS-SIJ). An adaptive multicriteria decision analysis was performed using the 1000Minds web application to determine the relative weights of the items in the JAMRIS-SIJ inflammation and damage domains. Experts in imaging and rheumatology independently completed a conjoint analysis survey (CAS) to determine the point value of the measurement items of the JAMRIS-SIJ. Each CAS survey question asked the expert to compare two hypothetical patient profiles, which were otherwise similar but different at two items at a time, and to select which item showed a more severe stage of inflammation or osteochondral damage. In addition, experts ranked 14 JAMRIS-SIJ grade only or image + grade patient vignettes while blinded to the CAS-derived weights. The validity of the weighted JAMRIS-SIJ was tested by comparing the expert CAS-weighted score and the image + grade ranking method. Seventeen experts completed the CAS (11 radiologists and 6 rheumatologists). Considering the point value for inflammation domain items, osteitis (24.7%) and bone marrow edema (24.3%) had higher group-averaged percentage weights compared to inflammation in erosion cavity (16.9%), joint space enhancement (13.1%), joint space fluid (9.1%), capsulitis (7.3%), and enthesitis (4.6%). Similarly, concerning the damage domain, ankylosis (41.3%) and erosion (25.1%) showed higher group-averaged weights compared to backfill (13.9%), sclerosis (10.7%), and fat metaplasia lesion (9.1%). The Spearman correlation coefficients of the CAS-weighted vignette order and unweighted JAMRIS-SIJ grade only order vignettes for all experts were 0.79 for inflammation and 0.80 for damage. The correlations of image vignettes among imaging experts to CAS were 0.75 for inflammation and 0.90 for damage. The multicriteria decision analysis identified differences in relative weights among the JAMRIS-SIJ measurement items. The determination of the relative weights provided expert-driven score scaling and face validity for the JAMRIS-SIJ, enabling the future evaluation of its longitudinal construct validity.

MRI of the temporomandibular joint in children with juvenile idiopathic arthritis: protocol and findings.

Contrast-enhanced magnetic resonance imaging (MRI) is the technique of choice for diagnosis and monitoring of temporomandibular joint (TMJ) disorders in patients with juvenile idiopathic arthritis (JIA), as it is able to visualize both soft tissue and osteochondral changes. Approximately 40% of children with JIA develop inflammatory and chronic osteochondral changes observable on imaging, which if left untreated can lead to significant facial growth impairment, including facial asymmetry and retrognathia. MRI of the TMJ plays a paramount role in diagnosis and treatment monitoring in JIA since early signs of TMJ involvement are difficult to detect clinically and with physical examination. Findings of TMJ arthritis may be classified into acute and chronic domains. Early or acute manifestations include joint effusion, bone marrow edema, synovial thickening, and increased joint enhancement. With disease progression, there are characteristic osteochondral changes, including deformity of the mandibular condyle with shortening of the mandibular ramus, bone erosions, and disk abnormalities. In this pictorial essay, we describe a consensus MRI protocol for the study of the TMJ and illustrate the degree of normal and pathological MRI findings using currently available MRI scoring systems of the TMJ developed for JIA.

US for Evaluation of Acute Abdominal Conditions in Neonates.

US is the imaging modality of choice for evaluation of a variety of abdominal conditions, and in recent years it has also become useful and promising as a bedside technique for assessment of acute abdominal conditions in neonates. Bedside US can help, complement, and sometimes replace radiographic or contrast-enhanced studies in critically ill and labile neonates who are difficult to transport to the fluoroscopy suite. Some of the features of bedside US can be applied as point-of-care US (POCUS) of the sick neonate. Some of the abdominal conditions in neonates that can be assessed and monitored with bedside US are necrotizing enterocolitis and its complications, malrotation with a midgut volvulus, segmental volvulus, meconium peritonitis, and complicated inguinal hernia. High-resolution US with the use of 15-MHz and higher-frequency probes allows characterization of the bowel anatomy and features of intestinal abnormalities in neonates in fine detail. Color Doppler US and microvascular imaging improve accuracy in the detection and characterization of bowel vascularity, which is important in the treatment and follow-up of patients with intestinal conditions. © RSNA, 2023 Quiz questions for this article are available through the Online Learning Center. The slide presentation from the RSNA Annual Meeting is available for this article.

Subcutaneous fat necrosis of the newborn: a pictorial essay of an under-recognized entity.

Subcutaneous fat necrosis of the newborn is a self-limited disorder predominantly affecting full-term and post-term neonates during the first 6 weeks after birth. Subcutaneous fat necrosis can be focal or multifocal and affect one or both sides with a predilection for areas of pressure in certain anatomical areas. Subcutaneous fat necrosis of the newborn is associated with perinatal asphyxia and other neonatal and maternal risk factors. Subcutaneous fat necrosis of the newborn presents as a self-limited area of dermal edema followed by indurated subcutaneous plaques, or nontender and mobile nodules, sometimes with skin discoloration [1-3]. The diagnosis is based on the child's history and physical examination, but when in doubt, imaging is helpful. US is the imaging modality of choice to confirm the diagnosis of subcutaneous fat necrosis of the newborn because it provides the best resolution of superficial lesions, requires no sedation and lacks ionizing radiation. US can also help evaluate and characterize other pathologies affecting the superficial subcutaneous soft tissues at this age. Familiarity with subcutaneous fat necrosis of the newborn is important to make a prompt and precise diagnosis and avoid unnecessary imaging tests or invasive procedures.

Multiparametric MRI evaluation of bone sarcomas in children.

Osteosarcoma and Ewing sarcoma are the most common bone sarcomas in children. Their clinical presentation is very variable depending on the age of the patient and tumor location. MRI is the modality of choice to assess these bone sarcomas and has an important function at diagnosis and also for monitoring recurrence or tumor response. Anatomic sequences include T1- and T2-weighted images and provide morphological assessment that is crucial to localize the tumor and describe anatomical boundaries. Multiparametric MRI provides functional information that helps in the assessment of tumor response to therapy by using different imaging sequences and biomarkers. This review manuscript illustrates the role of MRI in osteosarcoma and Ewing sarcoma in the pediatric population, with emphasis on a functional perspective, highlighting the use of diffusion-weighted imaging and dynamic contrast-enhanced MRI at diagnosis, and during and after treatment.

Discrete Choice Experiment on a Magnetic Resonance Imaging Scoring System for Temporomandibular Joints in Juvenile Idiopathic Arthritis.

OBJECTIVE: To determine the relative importance weights of items and grades of a newly developed additive outcome measure called the juvenile idiopathic arthritis (JIA) magnetic resonance imaging (MRI) scoring system for the temporomandibular joint (TMJ) (JAMRIS-TMJ). METHODS: An adaptive partial-profile, discrete choice experiment (DCE) survey using the 1000Minds platform was independently completed by members of an expert group consisting of radiologists and non-radiologist clinicians to determine the group-averaged relative weights for the JAMRIS-TMJ. Subsequently, an image-based vignette ranking exercise was done, during which experts individually rank ordered 14 patient vignettes for disease severity while blinded to the weights and unrestricted to JAMRIS-TMJ assessment criteria. Validity of the weighted JAMRIS-TMJ was tested by comparing the consensus-graded, DCE-weighted JAMRIS-TMJ score of the vignettes with their unrestricted image-based ranks provided by the experts. RESULTS: Nineteen experts completed the DCE survey, and 21 completed the vignette ranking exercise. Synovial thickening and joint enhancement showed higher weights per raw score compared to bone marrow items and effusion in the inflammatory domain, while erosions and condylar flattening showed nonlinear and higher weights compared to disk abnormalities in the damage domain. The weighted JAMRIS-TMJ score of the vignettes correlated highly with the ranks from the unrestricted comparison method, with median Spearman's ρ of 0.92 (interquartile range [IQR] 0.87-0.95) for the inflammation and 0.93 (IQR 0.90-0.94) for the damage domain. CONCLUSION: A DCE survey was used to quantify the importance weights of the items and grades of the JAMRIS-TMJ. The weighted score showed high convergent validity with an unrestricted, holistic vignette ranking method.

An algorithm combining procalcitonin and lung ultrasound improves the diagnosis of bacterial pneumonia in critically ill children: The PROLUSP study, a randomized clinical trial.

BACKGROUND: Lung ultrasound (LUS) and procalcitonin (PCT) are independently used to improve accuracy when diagnosing lung infections. The aim of the study was to evaluate the accuracy of a new algorithm combining LUS and PCT for the diagnosis of bacterial pneumonia. METHODS: Randomized, blinded, comparative effectiveness clinical trial. Children <18 years old with suspected pneumonia admitted to pediatric intensive care unit were included, and randomized into experimental group (EG) or control group (CG) if LUS or chest X-Ray (CXR) were done as the first pulmonary image, respectively. PCT was determined. In patients with bacterial pneumonia, sensitivity, specificity, and predictive values of LUS, CXR, and of both combined with PCT were analyzed and compared. Concordance between the final diagnosis and the diagnosis concluded through the imaging test was assessed. RESULTS: A total of 194 children, with a median age of 134 (interquartile range [IQR]: 39-554) days, were enrolled, 96 randomized into the EG and 98 into the CG. Bacterial pneumonia was diagnosed in 97 patients. Sensitivity and specificity for bacterial pneumonia diagnosis were 78% (95% confidence interval [CI]: 70-85) and 98% (95% CI: 93-99) for LUS, 85% (95% CI: 78-90) and 53% (95% CI: 43-62) for CXR, 90% (95% CI: 83-94) and 85% (95% CI: 76-91) when combining LUS and PCT, and 95% (95% CI: 90-98) and 41% (95% CI: 31-52) when combining CXR and PCT. The positive predictive value for LUS and PCT was 88% (95% C:I 79%-93%) versus 68% (95% CI: 60-75) for CXR and PCT. The concordance between the final diagnosis and LUS had a kappa value of 0.69 (95% CI: 0.62-0.75) versus 0.34 (95% CI: 0.21-0.45) for CXR, (p < 0.001). CONCLUSIONS: The combination of LUS and PCT presented a better accuracy for bacterial pneumonia diagnosis than combining CXR and PCT. Therefore, its implementation could be a reliable tool for pneumonia diagnosis in critically ill children.

Postsurgical Evaluation of the Pediatric Foot and Ankle.

This article reviews situations in which surgical treatment is required in the context of different types of pathology in the foot and ankle of children, focusing on the role of imaging in surgical planning and postsurgical assessment. The types of pathology analyzed from this perspective are congenital pathology, neuromuscular disorders, osteochondral lesions, fractures and infection, ligament injuries, and tumors.We address the most common pitfalls of postsurgical imaging of the ankle and foot in children. With some exceptions, postsurgical follow-up focuses on clinical assessment, with imaging follow-up only needed in patients where complications are suspected or symptoms recur. Postoperative assessment of the foot and ankle in children and adolescents requires knowing the indications for surgery and the most common types of interventions, along with their imaging characteristics. The radiologist needs to be aware of the normal sequence of development of structures and how to select adequate imaging techniques to assess anatomy at various stages or in different postsurgical scenarios.

Omphalomesenteric Duct Anomalies in Children: A Multimodality Overview.

The omphalomesenteric duct is an embryologic structure that connects the yolk sac with the primitive midgut of the developing fetus. Omphalomesenteric duct anomalies include a group of entities that result from failed resorption of the omphalomesenteric duct. These anomalies include Meckel diverticulum, omphalomesenteric fistula, fibrous bands, cysts, and umbilical polyps. Meckel diverticulum is the most common congenital anomaly of the gastrointestinal tract and is usually asymptomatic. Symptoms develop when Meckel diverticulum involves complications such as hemorrhage, inflammation, and perforation, or when it causes intussusception or bowel obstruction. Hemorrhage is the most common complication of Meckel diverticulum, and technetium 99m-pertechnetate scintigraphy is the imaging modality of choice for detecting acute bleeding. US and CT are commonly used for the evaluation of patients with other complications such as obstruction and inflammation. Nevertheless, the diagnosis of these complications can be challenging, as their clinical manifestations are usually nonspecific and can masquerade as other acute intraabdominal entities such as appendicitis, inflammatory bowel disease, or other causes of bowel obstruction. There are other umbilical disorders, such as urachal remnants and umbilical granuloma, that may present with symptoms and imaging findings similar to those of omphalomesenteric duct anomalies. An accurate preoperative diagnosis of omphalomesenteric duct anomaly is crucial for appropriate management and a better outcome, particularly when these anomalies manifest as a life-threatening condition. The authors review the anatomy, clinical features, and complications of omphalomesenteric duct anomalies in children, describing the relevant differential diagnoses and associated imaging findings seen with different imaging modalities. ©RSNA, 2021.

Assessing the Reliability of the OMERACT Juvenile Idiopathic Arthritis Magnetic Resonance Scoring System for Temporomandibular Joints (JAMRIS-TMJ).

Contrast-enhanced magnetic resonance imaging (MRI) remains the most comprehensive modality to assess juvenile idiopathic arthritis (JIA)-related inflammation and osteochondral damage in the temporomandibular joints (TMJ). This study tested the reliability of a new JIA MRI scoring system for TMJ (JAMRIS-TMJ) and the impact of variations in calibration and reader specialty. Thirty-one MRI exams of bilateral TMJs were scored independently using the JAMRIS-TMJ by 20 readers consisting of radiologists and non-radiologist clinicians in three reading groups, with or without a calibrating atlas and/or tutorial. The inter-reader reliability in the multidisciplinary cohort assessed by the generalizability coefficient was 0.61-0.67 for the inflammatory and 0.66-0.74 for the damage domain. The atlas and tutorial did not improve agreement within radiologists, but improved the agreement between radiologist and non-radiologist groups. Agreements between different calibration levels were 0.02 to 0.08 lower by the generalizability coefficient compared to agreement within calibration levels; agreement between specialty groups was 0.04 to 0.10 lower than within specialty groups. Averaging two radiologists raised the reliability above 0.8 for both domains. Therefore, the reliability of JAMRIS-TMJ was moderate-to-good depending on the presence of specialty and calibration differences. The atlas and tutorial are necessary to improve reliability when the reader cohort consists of multiple specialties.

Percutaneous cryoablation of chondroblastoma and osteoblastoma in pediatric patients.

BACKGROUND: To review the safety and efficacy of percutaneous cryoablation for the treatment of chondroblastoma and osteoblastoma in the pediatric and adolescent population. MATERIALS AND METHODS: A retrospective review from 2016 to 2020 was performed to evaluate clinical and imaging response to percutaneous cryoablation in 11 symptomatic patients with diagnosis of chondroblastoma and osteoblastoma treated from two pediatric hospitals with at least 12-month follow-up. Technical success (correct needle placement and potential full coverage of the tumor with the planned ablation zone) and clinical success (relief of the symptoms) were evaluated. The primary objective was to alleviate pain related to the lesion(s). Immediate and late complications were recorded. Patients were followed in clinic and with imaging studies such as MRI or CT for a minimum of 6 months. RESULTS: A total of 11 patients were included (mean 14 years, age range 9-17; male n = 8). Diagnoses were osteoblastoma (n = 4) and chondroblastoma (n = 7). Locations were proximal humerus (n = 1), femur condyle (n = 1), and proximal femur (n = 1) tibia (n = 3), acetabulum (n = 3), thoracic vertebra (n = 1) and lumbar vertebra (n = 1). Cryoablation was technically successful in all patients. Clinical success (cessation of pain) was achieved in all patients. No signs of recurrence were observed on imaging follow-up in any of the patients. One of the patients developed periprocedural right L2-L3 transient radiculopathy as major immediate complication. CONCLUSIONS: Percutaneous image-guided cryoablation can be considered potentially safe and effective treatment for chondroblastoma and osteoblastoma in children and adolescents.

Toward Developing a Semiquantitative Whole Body-MRI Scoring for Juvenile Idiopathic Arthritis: Critical Appraisal of the State of the Art, Challenges, and Opportunities.

With powerful new therapies available for management of juvenile idiopathic arthritis (JIA), early diagnosis leading to appropriate treatment may prevent long-term structural joint damage. Although magnetic resonance imaging (MRI) is typically used to assess individual body parts, indications for whole body (WB) MRI are increasing. Its utility as a diagnostic and monitoring tool has already been widely investigated in adult rheumatology patients, but less so in pediatric rheumatologic patients. This paper is a comprehensive review of scoring systems and a proposal for the conceptual development of a WB-MRI scoring system for the evaluation of JIA. In this review we identify, summarize, and critically appraise the available literature on the use of WB-MRI in inflammatory arthritis, addressing relevant considerations on components of a classification system that can lead to the development of a future pediatric WB-MRI scoring system for use in children with JIA. We also discuss advantages and challenges of developing such a WB-MRI scoring system for assessment of JIA and outline next steps toward the conceptual development of this scoring system.

MRI of Rhabdomyosarcoma and Other Soft-Tissue Sarcomas in Children.

Soft-tissue sarcomas in children comprise a heterogeneous group of entities with variable manifestation depending on the age of the patient and the location of the tumor. MRI is the modality of choice for evaluating musculoskeletal soft-tissue tumors and plays a paramount role in both initial diagnosis and assessment of tumor response during and after treatment. Conventional MRI sequences, such as T1- and T2-weighted imaging, offer morphologic information, which is important for localizing the lesion and describing anatomic relationships but not accurate for determining its malignant or benign nature and may be limited in differentiating tumor response from therapy-related changes. Advanced multiparametric MRI offers further functional information that can help with these tasks by using different imaging sequences and biomarkers. The authors present the role of MRI in rhabdomyosarcoma and other soft-tissue sarcomas in children, emphasizing a multiparametric approach with focus on the utility and potential added value of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced MRI in characterization and staging, determination of pretreatment extent, and evaluation of tumor response and recurrence after treatment. ©RSNA, 2020.