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Paragangliomas are neuroendocrine tumors that derive from paraganglia of the autonomic nervous system, with the majority of parasympathetic paragangliomas arising in the head and neck. More than one-third of all paragangliomas are hereditary, reflecting the strong genetic predisposition of these tumors. The molecular basis of paragangliomas has been investigated extensively in the past couple of decades, leading to the discovery of several molecular clusters and more than 20 well-characterized driver genes (somatic and hereditary), which are more than are known for any other endocrine tumor. Head and neck paragangliomas are largely related to the pseudohypoxia cluster and have been previously excluded from most molecular profiling studies. This review article introduces the molecular classification of paragangliomas, with a focus on head and neck paragangliomas, and discusses its impact on the management of these tumors. Genetic testing is now recommended for all patients with paragangliomas to provide screening and surveillance recommendations for patients and relatives. While CT and MRI provide excellent anatomic characterization of paragangliomas, gallium 68 tetraazacyclododecane tetraacetic acid–octreotate (ie, (68)Ga-DOTATATE) has superior sensitivity and is recommended as first-line imaging in patients with head and neck paragangliomas with concern for multifocal and metastatic disease, patients with known multifocal and metastatic disease, and in candidates for targeted peptide-receptor therapy. Keywords: Molecular Imaging, MR Perfusion, MR Spectroscopy, Neuro-Oncology, PET/CT, SPECT/CT, Head/Neck, Genetic Defects © RSNA, 2022

Texture analysis can quantify sophisticated imaging characteristics. We hypothesized that 2D textures computed with T2-weighted and post-contrast T1-weighted MRI can predict succinate dehydrogenase (SDH) mutation status in head and neck paragangliomas. Our retrospective study included 21 patients (1 to 4 tumors/patient) with 24 pathologically proven paragangliomas in the head and neck. Fourteen lesions (58%) were SDH mutation-positive. All patients underwent T2-weighted and post-contrast T1-weighted MRI sequences. Three 2D texture features of dependence non-uniformity normalized (DNN), small dependence high gray level emphasis (SDHGLE), and small dependence low gray level emphasis (SDLGLE) were calculated. Computed textures between SDH mutants and non-mutants were compared using Mann-Whitney U test. Area under the receiver operating characteristic (AUROC) curve was used to quantify the predictive power of each texture. Only T2-based SDLGLE was statistically significant (p = 0.048), and AUROC was 0.71. Diagnostic accuracy was 70.8%. 2D texture parameter of T2-based SDLGLE predicts SDH mutation in head and neck paragangliomas. This noninvasive technique can potentially facilitate further genetic workup.

Li-Fraumeni syndrome is a familial cancer predisposition syndrome associated with germline mutation of the tumor suppressor gene 53, which encodes the tumor suppressor p53 protein. Affected patients are predisposed to an increased risk of cancer development, including soft-tissue sarcomas, breast cancer, brain tumors, and adrenocortical carcinoma, among other malignancies. The tumor suppressor gene TP53 plays an important, complex role in regulating the cell cycle, collaborating with transcription factors and other proteins. The disruption of appropriate cell cycle regulation by mutated TP53 is considered to be the cause of tumorigenesis in Li-Fraumeni syndrome. Appropriate surveillance, predominantly by using MR imaging, is used for early malignancy screening in an effort to improve the survival rate among individuals who are affected. Patients with Li-Fraumeni syndrome are also at increased risk for neoplasm development after radiation exposure, and, therefore, avoiding unnecessary radiation in both the diagnostic and therapeutic settings is paramount. Here, we review the epidemiology, genetics, imaging findings, and the current standard surveillance protocol for Li-Fraumeni syndrome from the National Comprehensive Cancer Network as well as potential treatment options.Learning Objective: Describe the cause of second primary malignancy among patients with Li-Fraumeni syndrome.

Wernicke's encephalopathy (WE) is a severe and life-threatening illness resulting from vitamin B1 (thiamine) deficiency. The prevalence of WE has been estimated from 0.4 to 2.8%. If not treated properly, severe neurologic disorders such as Korsakoff psychosis and even death may occur. The classical triad of clinical symptoms (abnormal mental state, ataxia, and ophthalmoplegia) is found in only 16-33% of patients on initial examination. The originally described underlying condition of WE is alcoholism, but it accounts for about 50% of causes of WE. Nonalcoholic patients are also affected by WE and likely to present symptoms and radiological imaging findings different from patients with alcoholism, which further complicates the diagnosis of WE. Being familiar with predisposing causes, symptoms and radiological imaging findings of WE is important for radiologists and clinicians when making the diagnosis to start immediate treatment. This review discusses pathophysiologies, underlying causes, clinical symptoms, imaging findings and their mimics.

This case represents the unique occurrence of supratentorial dissemination of medulloblastoma in the absence of overt cerebellar disease. The authors present the case of a 64-year-old man who presented with headaches and intractable nausea with imaging abnormality seen only in the bilateral caudate. Follow-up imaging studies revealed a cerebellar lesion later confirmed by biopsy to be medulloblastoma. Subsequent biopsy of the originally evaluated caudate lesion demonstrated histologically identical medulloblastoma. Medulloblastoma should be considered in cases of supratentorial masses of unclear origin and should prompt careful inspection of the posterior fossa.

Tryptophan (TRP), a precursor of serotonin is believed to have an antidepressant effect. The pathway for brain uptake of TRP is shared by other large neutral amino acids; therefore, the best time to take TRP may be between meals. No previous study has, however, designated the time of TRP dosing to improve mood. Further, the effects of TRP on autonomic nervous system (ANS) activity are unclear. This study investigated the effects of TRP, vitamin B6, and nicotinamide-containing supplements loading between meals on mood and ANS activity in depressive young adults. Thirty depressive young adults were randomly allocated to receive TRP, vitamin B6, and nicotinamide-containing supplements or a placebo supplements twice daily between meals for 7 d. Mood was measured using the Center for Epidemiologic Studies Depression Scale (CES-D) and the Profile of Mood States (POMS). ANS activities were analyzed by heart rate variability power spectral analysis. Blood samples were assayed for plasma total TRP concentration. For analysis, TRP and placebo groups were further classified into two subgroups according to CES-D score (mild to moderate vs. severe depressive symptoms). The CES-D score significantly improved following both treatments in the severe depression subgroups, while the POMS depression score was significantly improved only in the TRP severe depression subgroup. There was no significant change in ANS activity or plasma total TRP in any group. TRP, vitamin B6, and nicotinamide-containing supplements loading between meals can quickly improve depressed mood in quite low dose in young adults with severe subclinical depression.

This presentation is aimed to •Understand normal and abnormal human development causing the ectopic tissues or organs. •Recognize clinical and radiological features of these ectopic tissues focusing on the anatomical correlations and genetic factors. •Identify the complications, the differential diagnoses and key findings of the ectopic tissues for the correct diagnosis. Table of contents I.Introduction to human development From zygote to each organ: How does the ectopic tissue or heterotopic tissue develop? Signaling pathway and gene mutations which cause malformations or affect the development of organ systems. II.Normal and abnormal human development, with the aspect of diagnostic radiology : divided into five areas. Brain, Head and neck, Chest, Abdomen, Bone and soft tissue. III.Case based review 1.Brain: Periventricular nodular heterotopia, Focal cortical dysplasia, Ectopic posterior pituitary 2.Head and neck: Ectopic thyroid tissue, Ectopic parathyroid gland, Ectopic thymic tissue thymoma 3.Chest: Ectopic mammary gland, Ectopic pulmonary calcification 4.Abdomen: Ectopic bile duct, Ectopic pancreatic tissue, Annular pancreas, Wandering spleen, Intrahepatic accessory spleen, Adrenal rest tumor, Ectopic kidney, Ectopic ureteral meatus, Heterotopic endometriosis 5.Bone and soft tissue: Ectopic bone formation, IV.Summary, RSNA 2021

Differentiation of meningiomas, paragangliomas, and schwannomas in the cerebellopontine angle and jugular foramen remains challenging when conventional MRI findings are inconclusive. This study aimed to assess the clinical utility of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced MRI (DCE-MRI) findings for tumor type differentiation and to identify the most significant diagnostic parameters.This retrospective study included 57 patients with pathologically confirmed meningiomas, paragangliomas, and schwannomas, diagnosed between January 2018 and August 2021. DWI and DCE-MRI were obtained before surgery. The apparent diffusion coefficient (ADC) and DCE-MRI parameters were calculated. The Kruskal-Wallis H test and post hoc test with Bonferroni correction and receiver operating characteristic curve were used for statistical analysis.There were 20 meningiomas (6 men; 62.3 ± 17.8 years), 23 paragangliomas (3 men; 51.6 ± 17.0 years), and 14 schwannomas (7 men; 37.7 ± 20.0 years). VDCE-MRI can provide promising parameters to differentiate meningiomas, paragangliomas, and schwannomas in the cerebellopontine angle and jugular foramen.

This article discusses new diffusion-weighted imaging (DWI) sequences, diffusion tensor imaging (DTI), and fiber tractography (FT), as well as more advanced diffusion imaging in pediatric brain and spine. Underlying disorder and pathophysiology causing diffusion abnormalities are discussed. Multishot echo planar imaging (EPI) DWI and non-EPI DWI provide higher spatial resolution with less susceptibility artifact and distortion, which are replacing conventional single-shot EPI DWI. DTI and FT have established clinical significance in pediatric brain and spine. This article discusses advanced diffusion imaging, including diffusion kurtosis imaging, neurite orientation dispersion and density imaging, diffusion spectrum imaging, intravoxel incoherent motion, and oscillating-gradient spin-echo.

Background and purpose Astroblastoma is a rare type of glial tumor, histologically classified into two types with different prognoses: high and low grade. We aimed to investigate the CT and MRI findings of astroblastomas by collecting studies with analyzable neuroimaging data and extracting the imaging features useful for tumor grading. Methods We searched for reports of pathologically proven astroblastomas with analyzable neuroimaging data using PubMed, Scopus, and Embase. Sixty-five studies with 71 patients with astroblastomas met the criteria for a systematic review. We added eight patients from our hospital, resulting in a final study cohort of 79 patients. The proportion of high-grade tumors was compared in groups based on the morphology (typical and atypical) using Fisher's exact test. Results High- and low-grade tumors were 35/71 (49.3%) and 36/71 (50.7%), respectively. There was a significant difference in the proportion of high-grade tumors based on the tumor morphology (typical morphology: high-grade = 33/58 [56.9%] vs. atypical morphology, 2/13 [15.4%], p = .012). The reviews of neuroimaging findings were performed using the images included in each article. The articles had missing data due to the heterogeneity of the collected studies. Conclusions Detailed neuroimaging features were clarified, including tumor location, margin status, morphology, CT attenuation, MRI signal intensity, and contrast enhancement pattern. The classification of tumor morphology may help predict the tumor's histological grade, contributing to clinical care and future oncologic research.

BACKGROUND AND PURPOSE: Distinguishing schwannomas from paragangliomas in the head and neck and determining succinate dehydrogenase (SDH) mutation status in paragangliomas are clinically important. We aimed to assess the clinical usefulness of DWI and dynamic contrast-enhanced MR imaging in differentiating these 2 types of tumors, as well as the SDH mutation status of paragangliomas. MATERIALS AND METHODS: This retrospective study from June 2016 to June 2020 included 42 patients with 15 schwannomas and 27 paragangliomas (10 SDH mutation-positive and 17 SDH mutation-negative). ADC values, dynamic contrast-enhanced MRI parameters, and tumor imaging characteristics were compared between the 2 tumors and between the mutation statuses of paragangliomas as appropriate. Multivariate stepwise logistic regression analysis was performed to identify significant differences in these parameters. RESULTS: Fractional plasma volume (P ≤ .001), rate transfer constant (P = .038), time-to-maximum enhancement (P < .001), maximum signal-enhancement ratio (P < .001) and maximum concentration of contrast agent (P < .001), velocity of enhancement (P = .002), and tumor characteristics including the presence of flow voids (P = .001) and enhancement patterns (P = .027) showed significant differences between schwannomas and paragangliomas, though there was no significant difference in ADC values. In the multivariate logistic regression analysis, fractional plasma volume was identified as the most significant value for differentiation of the 2 tumor types (P = .014). ADC values were significantly higher in nonhereditary than in hereditary paragangliomas, while there was no difference in dynamic contrast-enhanced MR imaging parameters. CONCLUSIONS: Dynamic contrast-enhanced MR imaging parameters show promise in differentiating head and neck schwannomas and paragangliomas, while DWI can be useful in detecting SDH mutation status in paragangliomas.

BACKGROUND AND PURPOSE To evaluate the differences in the imaging findings of intracranial solitary fibrous tumor (SFT) and meningioma on dynamic susceptibility contrast (DSC) perfusion MRI, apparent diffusion coefficient (ADC), and conventional sequences. METHODS Between January 2016 and April 2022, the study enrolled 14 (median, 46 years [range, 25–74]; six females; seven with DSC-MRI) and 27 patients (median, 53 years [21–83]; 23 females; all with DSC-MRI) with pathologically proven SFT and meningioma, respectively. The normalized relative cerebral blood volume and flow (nrCBV and nrCBF), percentage signal recovery (PSR), normalized mean ADC (nADCmean), and conventional imaging features, including T1-weighted hyperintensity, were evaluated and statistically compared using Bonferonni correction. RESULTS PSR was significantly lower in SFT compared with that in meningioma (median, 22.5 [range, 6.4–48.8] vs. 70.1 [range, 18.6–104.2], p< 0.001). The majority of SFT showed mainly T1-weighted hyperintensities compared to the gray matter, while only one meningioma showed the finding (8/14 [57.1%] vs. 1/27 [3.7%], p< 0.001). No significant difference was observed in nrCBV, nrCBF, or nADCmean. CONCLUSIONS PFS was significantly lower in intracranial SFT compared with that in meningioma, indicating the difference in capillary permeability between the tumors. Comparing the hyperintensity on T1WI of the solid components with that of the cerebral cortex was a simple and useful characteristic to differentiate SFT from meningioma.

Diffuse midline gliomas, H3K27-altered (DMG-A), are malignant gliomas with an unfavorable prognosis. Knowledge of dynamic susceptibility contrast (DSC) MRI findings and imaging differences with high-grade midline glioma without H3K27 alteration (DMG-W) has been limited. We compared the DSC, ADC, and conventional MRI findings between DMG-A and DMG-W.In this single institutional retrospective study, the electronic database of our hospital between June 2015 and May 2021 was searched. Twenty and 17 patients with DMG-A (median, 13 years; range, 3-52 years; 11 females) and DMG-W (median, 40 years; 7-73 years; 9 females), respectively, were found. Normalized relative cerebral blood flow (nrCBF) and normalized corrected relative cerebral blood volume (ncrCBV); normalized maximum, mean, and minimum ADC values; and the prevalence of T2-FLAIR mismatch sign were compared between the two groups using Mann-Whitney U tests and Fisher's exact test.The nrCBF and ncrCBV were significantly lower in DMG-A compared with DMG-W (nrCBF: median 0.88 [range, 0.19-2.67] vs. 1.47 [range, 0.57-4.90] (p 0.001); ncrCBV: 1.17 [0.20-2.67] vs. 1.56 [0.60-4.03] (p = 0.008)). Normalized maximum ADC (nADCDSC-MRI parameters, ADC values, and the T2-FLAIR mismatch sign are useful to differentiate between DMG-A and DMG-W.• Diffuse midline glioma, H3K27-altered (DMG-A), showed a significantly lower normalized relative cerebral blood flow and volume compared with H3K27-wild-type counterparts (DMG-W). • T2-fluid-attenuated inversion recovery (FLAIR) mismatch sign was significantly more frequent in DMG-A compared to DMG-W. • Indicators that combined DSC parameters, ADC values, and T2-FLAIR mismatch sign, with or without age, are useful to distinguish the two tumors.

Assessments of both neural and muscular adaptations during interventions would provide valuable information for developing countermeasures to age-related muscle dysfunctions. We investigated the effect of fish protein ingestion on training-induced neural and muscular adaptations in older adults. Twenty older adults participated 8 weeks of isometric knee extension training intervention. The participants were divided into two groups who took fish protein (n = 10, Alaska pollack protein, APP) or casein (n = 10, CAS). Maximal muscle strength during knee extension, lower extremity muscle mass (body impedance method), and motor unit firing pattern of knee extensor muscle (high-density surface electromyography) were measured before, during, and after the intervention. Muscle strength were significantly increased in both CAS (124.7 ± 5.8%) and APP (117.1 ± 4.4%) after intervention (p < .05), but no significant differences between the groups were observed (p > .05). Significant increases in lower extremity muscle mass from 0 to 8 weeks were demonstrated only for APP (102.0 ± 3.2, p < .05). Greater changes in motor unit firing pattern following intervention were represented in CAS more than in APP. These results suggest that nutritional supplementations could modulate neural and muscular adaptations following resistance training and fish protein ingestion preferentially induces muscular adaptation without the detectable neural adaptation in older adults.

Objective: Magnetic resonance imaging (MRI) has been investigated extensively in its success or failure to identify preoperative vascular compression in patients with trigeminal neuralgia (TN). To this end, we reviewed our case load to evaluate the concordance or discordance between preoperative MRI and intraoperative findings. Patients and Methods: Sixty-nine patients with Type 1 TN and retrievable MRI images, operative reports, and intraoperative photographs were retrospectively reviewed. Results: Our review shows that MRI predicted conflict (arterial or venous) in 58 cases that was confirmed at surgery in 55 cases. MRI predicted no conflict in 11 cases, whereas surgery revealed no conflict in a total of 6 cases. Thus, in predicting conflict at surgery, MRI had a sensitivity of 87%, and specificity of 50%, respectively. Conversely, MRI accurately predicted intraoperative conflict (positive predictive value) in 95% of cases, and the absence of conflict (negative predictive value) in 27%. These results reveal that MRI is more accurate in predicting conflict than the absence of conflict at surgery. Conclusion: Our results support the reliance on the clinical diagnosis of Type 1 TN to recommend microvascular decompression (MVD). The presence of vascular compression by MRI should encourage the surgeon to persevere in search of the offending vessel when it proves elusive. MRI positive and negative predictive values for conflict are expected to increase with better resolution imaging. The absence of neurovascular conflict on high-resolution MRI should not negate MVD in the treatment of a patient with classic TN.

Acute changes in mental status represent a broad collection of symptoms used to describe disorders in mentation and level of arousal, including the more narrowly defined diagnoses of delirium and psychosis. A wide range of precipitating factors may be responsible for symptom onset including infection, intoxication, and metabolic disorders. Neurologic causes that may be detected on neuroimaging include stroke, traumatic brain injury, nonconvulsive seizure, central nervous system infection, tumors, hydrocephalus, and inflammatory disorders. Not infrequently, two or more precipitating factors may be found. Neuroimaging with CT or MRI is usually appropriate if the clinical suspicion for an acute neurological cause is high, where the cause of symptoms is not found on initial assessment, and for patients whose symptoms do not respond appropriately to management. There was disagreement regarding the appropriateness of neuroimaging in cases where a suspected, nonneurologic cause is found on initial assessment. Neuroimaging with CT is usually appropriate for patients presenting with delirium, although the yield may be low in the absence of trauma or a focal neurological deficit. Neuroimaging with CT or MRI may be appropriate in the evaluation of new onset psychosis, although the yield may be low in the absence of a neurologic deficit. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

A palpable neck mass may be the result of neoplastic, congenital, or inflammatory disease. Older age suggests neoplasia, and a congenital etiology is more prevalent in the pediatric population. The imaging approach is based on the patient age, mass location, and clinical pulsatility. Underlying human papillomavirus-related malignancy should be considered in all age groups. Although the imaging appearance of some processes in the head and neck overlap, choosing the appropriate imaging examination may allow a specific diagnosis, or a limited differential diagnosis. Tissue sampling is indicated to confirm suspected malignancy. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Nontraumatic neck pain is a leading cause of disability, with nearly 50% of individuals experiencing ongoing or recurrent symptoms. Radiographs are appropriate as initial imaging for cervical or neck pain in the absence of "red flag" symptoms or if there are unchanging chronic symptoms; however, spondylotic changes are commonly identified and may result in both false-positive and false-negative findings. Noncontrast CT can be complementary to radiographs for evaluation of new or changing symptoms in the setting of prior cervical spine surgery or in the assessment of extent of ossification in the posterior longitudinal ligament. Noncontrast MRI is usually appropriate for assessment of new or increasing radiculopathy due to improved nerve root definition. MRI without and with contrast is usually appropriate in patients with new or increasing cervical or neck pain or radiculopathy in the setting of suspected infection or known malignancy. Imaging may be appropriate; however, it is not always indicated for evaluation of cervicogenic headache without neurologic deficit. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Maslinic acid, derived from olive fruit, reduces pro-inflammation cytokines, which are involved in muscle fiber atrophy. Therefore, the maslinic acid ingestion may enhance the muscular response to resistance training through anti-inflammatory action. We therefore conducted a parallel, double-blind, randomized, placebo-controlled trial that examined whether a combination of maslinic acid supplementation and resistance training improve mobility functions in community-dwelling elderly persons. Over a 12-week period, 36 participants underwent moderate resistance training and are assigned to the maslinic acid supplementation (n = 17, 60 mg/day) or the placebo (n = 19) group. At baseline and at 12-weeks, we assessed body composition, grip strength, walking speed, leg strength, mobility functions, and knee pain scores. Following the 12-weeks, skeletal muscle mass, segmental muscle mass (right arm, left arm, and trunk) and knee pain score of the right leg were significantly improved in the maslinic acid group, while there was no change or parameters had worsened in the placebo group. Grip strength of the better side significantly increased only in the maslinic acid group. These results suggest that maslinic acid supplementation combined with moderate resistance training may increase upper muscle mass and grip strength, and reduce knee pain, could be effective for preventing mobility-related disability in elderly persons. Clinical trial registration number: UMIN000017207.

OBJECTIVE. Tumefactive demyelination mimics primary brain neoplasms on imaging, often necessitating brain biopsy. This article reviews the literature for the clinical and radiologic findings of tumefactive demyelination in various disease processes to facilitate identification of tumefactive demyelination on imaging. CONCLUSION. Both clinical and radiologic findings must be integrated to distinguish tumefactive demyelinating lesions from similarly appearing lesions on imaging. Further research on the immunopathogenesis of tumefactive demyelination and associated conditions will elucidate their interrelationship.

Objective H3K27M mutation in gliomas has prognostic implications. Previous magnetic resonance imaging (MRI) studies have reported variable rates of tumoral enhancement, necrotic changes, and peritumoral edema in H3K27M-mutant gliomas, with no distinguishing imaging features compared with wild-type gliomas. We aimed to construct an MRI machine learning (ML)-based radiomic model to predict H3K27M mutation in midline gliomas. Methods A total of 109 patients from 3 academic centers were included in this study. Fifty patients had H3K27M mutation and 59 were wild-type. Conventional MRI sequences (T1-weighted, T2-weighted, T2–fluid-attenuated inversion recovery, postcontrast T1-weighted, and apparent diffusion coefficient maps) were used for feature extraction. A total of 651 radiomic features per each sequence were extracted. Patients were randomly selected with a 7:3 ratio to create training (n = 76) and test (n = 33) data sets. An extreme gradient boosting algorithm (XGBoost) was used in ML-based model development. Performance of the model was assessed by area under the receiver operating characteristic curve. Results Pediatric patients accounted for a larger proportion of the study cohort (60 pediatric [55%] vs. 49 adult [45%] patients). XGBoost with additional feature selection had an area under the receiver operating characteristic curve of 0.791 and 0.737 in the training and test data sets, respectively. The model achieved accuracy, precision (positive predictive value), recall (sensitivity), and F1 (harmonic mean of precision and recall) measures of 72.7%, 76.5%, 72.2%, and 74.3%, respectively, in the test set. Conclusions Our multi-institutional study suggests that ML-based radiomic analysis of multiparametric MRI can be a promising noninvasive technique to predict H3K27M mutation status in midline gliomas.

Diffusion-weighted images (DWI) are usually obtained in three orthogonal orientations using spin-echo type single-shot echo-planar imaging with b values around 0 and 1000 s/mm2. These three planes are combined into isotropic DWI, and apparent diffusion coefficient (ADC) maps are calculated on a pixel-by-pixel basis (Fig. 2.1). To avoid misinterpretations, it is important to recognize the normal findings on DWI and ADC maps.

Imaging section: Distinguishing between different types of spinal cord lesions is crucial because the treatments vary greatly: interventional procedures for vascular malformations, decompression surgery for compressive myelopathy, biopsy or resection for neoplasm, and steroids for inflammatory etiologies. However, spinal cord lesions remain a diagnostic challenge due to the wide range of etiologies and nonspecific clinical and imaging presentations. The development of new diffusion-weighted imaging (DWI) techniques with increased resolution and decreased magnetic susceptibility effects, such as BLADE-DWI and multi-shot echo planar DWI, has given radiologists an additional tool to help refine differential diagnoses. Although data is still limited, many investigators believe that DWI in combination with apparent diffusion coefficient (ADC) is more sensitive and specific for cord lesions than T2 weighting since these techniques provide physiologic information. Typically, etiologies that lead to cytotoxic edema (impaired free motion of water molecules), such as cord infarct, will show restricted diffusion (high DWI signal and decreased ADC). Additional etiologies that may show restriction of diffusion include acute demyelination, acute cord contusion, hypercellular tumor, infectious myelitis, and intramedullary abscess. On the other hand, vasogenic/interstitial edema, cystic necrosis, gliosis, fluid collection or increased extracellular matrix (promoting free diffusion of water molecules), such as in subacute to chronic inflammatory or demyelinating lesions, myelomalacia, compressive myelopathy, pre-syrinx/syrinx, hypocellular neoplasm tend to show increased ADC values.

Treatment section: Head and neck squamous cell carcinoma most commonly affects the oral cavity, oropharynx, and larynx. Traditional risk factors include tobacco, alcohol, and more recently high-risk strains of human papilloma virus (HPV). The mainstay of treatment includes surgery, radiation, and cytotoxic chemotherapy. Recent updates to diagnosis and staging criteria as well as primary treatment modalities are reviewed below for each head and neck subsite.

Central nervous system vasculopathy is an umbrella term for any abnormality of the blood vessels of the brain and spine, including vasculitis. CNS vasculitis can either be primary or secondary which encompasses a wide range of diagnoses. This chapter covers the treatment and management of these various entities.

Spinal tumors constitute a challenging and formidable diagnosis or disease for the radiologist, surgeon, and oncologist. These tumors can be benign or malignant. The diagnosis can be achieved with radiographic studies, but not always. The accuracy of diagnosis relies heavily on the experience and knowledge of the radiologist. Past medical history, blood tests, bone marrow aspiration, or biopsy of the lesion may be necessary. Biopsies are often inconclusive, necessitating additional attempts. Treatment may consist of observation with sequential studies. Benign and malignant tumors can result in varying degrees of symptoms and deficit. Hence, the accuracy in diagnosis and management is paramount. In some malignant tumors, radiation and chemotherapy may be recommended before surgery, but in most following surgery. Prior to surgery, vascular tumors, such as metastatic renal cell carcinomas or aneurysmal bone cysts, may require preoperative embolization. Depending on the location of the tumor, surgery may be indicated thorough a posterior approach, other times anterior, and sometimes lateral, as in transthoracic or retroperitoneal. Surgery may consist of decompression. Other times, instrumentation is required to maintain stability. Such procedures are often lengthy, associated with significant blood loss, with risk of intraoperative as well as postoperative complications.

Structural and metabolic neuroimaging techniques have made substantial contributions in the understanding of neurodegenerative diseases and provide essential biomarkers for developing new treatments. Presented in this chapter are the most prevalent primary neurodegenerative conditions such as Alzheimer’s, Lewy body, and Parkinson diseases, as well as frontotemporal lobar degeneration, other tauopathies and alpha-synucleinopathies, motor system degeneration, and prion diseases. Secondary neuronal degeneration is frequently recognized in association with prevalent destructive brain conditions such as stroke, and is presented thereafter with emphasis on the DWI findings.

The aim of this chapter is to help the reader understand major topics and various cases of DWI in this book visually.

There are many inherent artifacts and pitfalls in diffusion-weighted imaging (DWI) of the brain that are important to recognize to avoid misinterpretations.

Purpose The aims of the present study were: (a) to examine the effect of the stimulus intensity on force‐frequency and torque fluctuation–frequency relationships during Neuromuscular electrical stimulation; and (b) to identify a novel parameter that can be used to evaluate muscle contractile properties. Methods: Electrically elicited joint torque involving the quadriceps femoris muscle was recorded during neuromuscular electrical stimulation at two different stimulus intensities in 19 healthy men. Stimulation frequencies were set at 5–40 Hz with a duration of 10 s. Evoked joint torque was compared among all stimulation frequencies between the two stimulus intensities (68 and 113 V). The torque fluctuation at each stimulation frequency as the change in the contraction pattern was also compared between the intensities. Torque and torque fluctuation were normalized at each frequency by the largest torque or torque fluctuation, respectively. We extracted a novel parameter: the arrival point of tetanic contraction based on force‐frequency and torque fluctuation‐frequency curves. Results: There were significant differences in normalized torque at 5–25 and 40 Hz and in normalized torque fluctuation at 15–30 and 40 Hz between the two stimulus intensities. Extracted parameters showed no significant difference between the intensities. Conclusion: The results suggest that force–frequency relationships during neuromuscular electrical stimulation are influenced by the intensity of stimulation applied to the quadriceps femoris muscle. However, we consider that it is possible to simultaneously evaluate contractile properties using the novel parameter., We tested the effect of stimulus intensity on force‐frequency relationship and torque fluctuation‐frequency relationship during neuromuscular electrical stimulation (NMES), and proposed new parameter to evaluate muscle contractile properties. We suggest that the stimulus intensity should be considered on investigating the force‐frequency relationship during NMES in the quadriceps femoris muscle. However, we suggest that simultaneously we can evaluate contractile properties with using new parameters.

BACKGROUND AND PURPOSE: Hypophysitis is one of the well-known adverse effects of immune checkpoint inhibitors. Immune checkpoint inhibitor–induced hypophysitis frequently causes irreversible hypopituitarism, which requires long-term hormone replacement. Despite the high frequency and clinical significance, characteristic MR imaging findings of immune checkpoint inhibitor–induced hypophysitis have not been established. In the present study, we aimed to review and extract the MR imaging features of immune checkpoint inhibitor–induced hypophysitis. MATERIALS AND METHODS: This retrospective international multicenter study comprised 20 patients with melanoma who were being treated with immune checkpoint inhibitors and clinically diagnosed with immune checkpoint inhibitor–induced hypophysitis. Three radiologists evaluated the following MR imaging findings: enlargement of the pituitary gland and stalk; homogeneity of enhancement of the pituitary gland; presence/absence of a well-defined poorly enhanced area and, if present, its location, shape, and signal intensity in T2WI; and enhancement pattern in contrast-enhanced dynamic MR imaging. Clinical symptoms and hormone levels were also recorded. RESULTS: Enlargement of the pituitary gland and stalk was observed in 12 and 20 patients, respectively. Nineteen patients showed poorly enhanced lesions (geographic hypoenhancing lesions) in the anterior lobe, and 11 of these lesions showed hypointensity on T2WI. Thyrotropin deficiency and corticotropin deficiency were observed in 19/20 and 12/17 patients, respectively, which persisted in 12/19 and 10/12 patients, respectively, throughout the study period. CONCLUSIONS: Pituitary geographic hypoenhancing lesions in the anterior lobe of the pituitary gland are characteristic and frequent MR imaging findings of immune checkpoint inhibitor–induced hypophysitis. They reflect fibrosis and are useful in distinguishing immune checkpoint inhibitor–induced hypophysitis from other types of hypophysitis/tumors.

Spinal pain, especially low back pain (LBP), is a widespread clinical and diagnostic problem for both patients and physicians, because back pain has an equivalently wide variety of causes and provocations. Because of its variable nature and manifestations, back pain is challenging to diagnose and treat correctly. In addition, the pain is induced not only by direct mechanical pressure such as a herniated disk or degenerated bone but also by inflammation and associated proinflammatory cytokines. To help guide further diagnostic workup or the next step in management, radiologists should be familiar with the causes, mechanisms, and diagnostic clues provided by MRI. The authors review the microscopic and macroscopic mechanisms for each category of LBP and depict the relationship between imaging findings and pain mechanisms. This review focuses on the detailed anatomy related to the pain-signaling pathway and the roles of chemicals in inducing different mechanisms of LBP. MRI findings that serve as representative examples of key concepts are demonstrated according to each mechanism, and treatment options are reviewed on the basis of different causes of LBP. By knowing these concepts, radiologists can help correlate imaging findings with potential underlying mechanisms and help guide clinicians in the management of LBP. ©RSNA, 2020.

Age-related sarcopenia is a progressive and generalized skeletal muscle disorder associated with adverse outcomes. Herein, we evaluate the effects of a combination of electrical muscle stimulation (EMS) and a whey-based nutritional supplement (with or without polyphenols and fish oil-derived omega-3 fatty acids) on muscle function and size. Free-living elderly participants with mobility limitations were included in this study. They received 2 sessions of EMS per week and were randomly assigned to ingest an isocaloric beverage and capsules for 12 weeks: (1) carbohydrate + placebo capsules (CHO, n = 12), (2) whey protein isolate + placebo capsules (WPI, n = 15) and (3) whey protein isolate + bioactives (BIO) capsules containing omega-3 fatty acids, rutin, and curcumin (WPI + BIO, n = 10). The change in knee extension strength was significantly improved by 13% in the WPI + BIO group versus CHO on top of EMS, while WPI alone did not provide a significant benefit over CHO. On top of this, there was the largest improvement in gait speed (8%). The combination of EMS and this specific nutritional intervention could be considered as a new approach for the prevention of sarcopenia but more work is needed before this approach should be recommended. This trial was registered at the Japanese University Hospital Medical Information Network (UMIN) clinical trial registry (UMIN000008382).

A 3-month-old male infant appeared on multiple clinical examinations to have acutely developed bilateral retrogeniculate blindness. Electroencephalography showed focal status epilepticus confined to the left posterior cerebral hemisphere. MRI demonstrated restricted diffusion in the domain of the left posterior cerebral artery consistent with acute stroke. Notably, the restricted diffusion extended across the midline in the splenium of the corpus callosum. This splenial sign may be the imaging correlate of cerebral diaschisis, a well-described phenomenon in which patients with new brain lesions develop acutely impaired neurologic function in related but nonlesioned brain regions. Diaschisis has been posited as the explanation for the temporary bilateral blindness in adult patients suffering from unilateral occipital infarctions.

Wernicke's encephalopathy (WE) is a severe and life-threatening illness resulting from vitamin B1 (thiamine) deficiency. The prevalence of WE has been estimated from 0.4 to 2.8%. If not treated properly, severe neurologic disorders such as Korsakoff psychosis and even death may occur. The classical triad of clinical symptoms (abnormal mental state, ataxia, and ophthalmoplegia) is found in only 16-33% of patients on initial examination. The originally described underlying condition of WE is alcoholism, but it accounts for about 50% of causes of WE. Nonalcoholic patients are also affected by WE and likely to present symptoms and radiological imaging findings different from patients with alcoholism, which further complicates the diagnosis of WE. Being familiar with predisposing causes, symptoms and radiological imaging findings of WE is important for radiologists and clinicians when making the diagnosis to start immediate treatment. This review discusses pathophysiologies, underlying causes, clinical symptoms, imaging findings and their mimics.