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The capabilities of and interest in artificial intelligence (AI) in healthcare, and more specifically, population health, has grown exponentially over the past decade. The vast volume of digital data or “big data” in the form of images generated by an aging population, with an ever-increasing demand for imaging, amassed by radiology departments, provides ample opportunity for AI application and has allowed radiology to become a service line leader of AI in the medical field. The screening and detection capabilities of AI make it a valuable tool in population health management, as organizations work to shift their services to early identification and intervention, especially as it relates to chronic disease. In this paper, the clinical, technological, and operational workflows that were developed and integrated within each other to support the adoption of AI algorithms aimed at detecting subclinical osteoporosis and coronary artery disease are described. The benefits of AI are reviewed and weighed against potential drawbacks within the context of population health management and risk contract arrangements. Mitigation tactics are discussed, as well as the anticipated outcomes in terms of cost-avoidance, physician use of evidence-based clinical pathways, and reduction in major patient events (e.g., stroke, hip fracture). The plan for data collection and analysis is also described for program evaluation.

Neurologic involvement has been reported in primary Sjogren’s syndrome (SS) in approximately 10–25% of cases 1, 2, 3. Peripheral neuropathy is a major neurological manifestation of Sjögren's syndrome 4 and its etiology has been considered to be vasculitis in the peripheral nerves 2. While neuropathic symptoms of SS can be varied, it is unusual to have two different types of neuropathic presentations simultaneously in a patient. We describe a case of Sjogren’s syndrome presenting with autonomic symptoms who was noted to have large fiber neuropathy on EMG and inflammatory changes on nerve biopsy.

We describe a rare case presenting with both signs of acute motor and sensory axonal neuropathy (AMSAN) and immune thrombocytopenic purpura (ITP) possibly triggered by Hemophilus influenzae. Guillain-Barre is an autoimmune disorder purported to be due to molecular mimicry, often with a preceding infection, leading to myelin sheath or even axonal damage, AMSAN, in the peripheral nervous system (PNS). Rarely, there have been case reports of concurrent acute autoimmune disorders leading to a more complex presentation and additional comorbidities. A 42-year-old man presented with 2 days of progressive lower and upper extremity paresthesia’s, ataxia preceded by an upper respiratory infection. Examination showed areflexia and purpura, recent oral mucosal hemorrhage. Lab results showed severe thrombocytopenia suspicious for ITP. Over the ensuing weeks while inpatient, his condition quickly deteriorated to requiring an intubation for respiratory failure and not immediately responsive to IVIG. Recovery, both for AMSAN confirmed by EMG and ITP, was eventually achieved with time and five treatments of plasmapheresis and eventually was discharged to a rehabilitation facility. A thorough infectious workup revealed a possible trigger being Haemophilus influenzae. There have been rare occasions of concurrent GBS and ITP, but even more rare is the presence of both AMSAN and ITP which requires quick recognition and evaluation. This case highlights the need for a thorough initial history taking and a general physical exam, in addition to unique management decisions and strategies in patients with suspected GBS as there may be signs of other associated disorders that require immediate attention.

In nearly every US state today, a large mismatch exists between the need for neurologists and neurological services and the availability of neurologists to provide these services. Patients with neurologic disorders are rising in prevalence and require access to high level care to reduce disability. The current neurology mismatch reduces access to care, worsens patient outcomes, and erodes career satisfaction and quality of life for neurologists as they face increasingly insurmountable demands. As a community, we must address this mismatch in the demand and supply of neurological care in an aggressive and sustained manner to ensure the future health of our patients and our specialty. The American Academy of Neurology has multiple ongoing initiatives to help reduce and resolve the existing mismatch. With the intent of raising awareness and widening the debate nationally, we present a strategic plan that the Academy could implement to coordinate and expand existing efforts. We characterize the suggested strategies as: shaping the demand, enhancing the workforce, and advocating for neurologist value The proposed framework is based on available data and expert opinion when data were lacking. Prioritization of strategies will vary by geography, practice setting, and local resources. We believe the time to act is now, to allow concerted effort and targeted interventions to avert this looming public health crisis.

eConsults provide a mechanism for specialists to provide guidance to their colleagues to allow them to manage patients in primary care settings. The patient receives access to specialist expertise, avoids the long wait time and high costs associated with an office visit, and maintains relationship continuity with the primary care physician (PCP). The PCP has dynamic access to specialist expertise and an opportunity for attainting a higher comfort level with chronic neurological care comanagement. Patient referrals for specialty care are high, while there has been projected shortage in nonprimary care specialties. The increasing prevalence of neurologic diseases associated with an aging population will likely continue to increase the demand for neurologists.

Pyridoxine (vitamin B6) toxicity is a well-known cause of primary sensory, length-dependent, axonal polyneuropathy. Although sensory symptoms predominate, autonomic symptoms have also been reported in some cases. To date, there is no objective evidence of autonomic dysfunction reported in the literature. We present the case of a 41-year-old woman with 2 years of progressive burning pain, numbness, tingling, and weakness in a stocking-glove distribution who was found to have severe pyridoxine toxicity. Concurrent presence of large and small fiber nerve dysfunction was noted in the form of abnormal electromyography/nerve conduction study demonstrating a chronic sensory polyneuropathy and autonomic testing demonstrating abnormal responses to quantitative sweat testing and cardiovagal function testing. This case highlights the need for consideration of small fiber nerve damage by obtaining autonomic testing in cases of pyridoxine toxicity.

Importance Cryptogenic sensory polyneuropathy (CSPN) is a common generalized slowly progressive neuropathy, second in prevalence only to diabetic neuropathy. Most patients with CSPN have significant pain. Many medications have been tried for pain reduction in CSPN, including antiepileptics, antidepressants, and sodium channel blockers. There are no comparative studies that identify the most effective medication for pain reduction in CSPN. Objective To determine which medication (pregabalin, duloxetine, nortriptyline, or mexiletine) is most effective for reducing neuropathic pain and best tolerated in patients with CSPN. Design, Setting, and Participants From December 1, 2014, through October 20, 2017, a bayesian adaptive, open-label randomized clinical comparative effectiveness study of pain in 402 participants with CSPN was conducted at 40 neurology care clinics. The trial included response adaptive randomization. Participants were patients with CSPN who were 30 years or older, with a pain score of 4 or greater on a numerical rating scale (range, 0-10, with higher scores indicating a higher level of pain). Participant allocation to 1 of 4 drug groups used the utility function and treatment’s sample size for response adaptation randomization. At each interim analysis, a decision was made to continue enrolling (up to 400 participants) or stop the whole trial for success (80% power). Patient engagement was maintained throughout the trial, which helped guide the study and identify ways to communicate and disseminate information. Analysis was performed from December 11, 2015, to January 19, 2018. Interventions Participants were randomized to receive nortriptyline (n = 134), duloxetine (n = 126), pregabalin (n = 73), or mexiletine (n = 69). Main Outcomes and Measures The primary outcome was a utility function that was a composite of the efficacy (participant reported pain reduction of ≥50% from baseline to week 12) and quit (participants who discontinued medication) rates. Results Among the 402 participants (213 men [53.0%]; mean [SD] age, 60.1 [13.4] years; 343 White [85.3%]), the utility function of nortriptyline was 0.81 (95% bayesian credible interval [CrI], 0.69-0.93; 34 of 134 [25.4%] efficacious; and 51 of 134 [38.1%] quit), of duloxetine was 0.80 (95% CrI, 0.68-0.92; 29 of 126 [23.0%] efficacious; and 47 of 126 [37.3%] quit), pregabalin was 0.69 (95% CrI, 0.55-0.84; 11 of 73 [15.1%] efficacious; and 31 of 73 [42.5%] quit), and mexiletine was 0.58 (95% CrI, 0.42-0.75; 14 of 69 [20.3%] efficacious; and 40 of 69 [58.0%] quit). The probability each medication yielded the highest utility was 0.52 for nortriptyline, 0.43 for duloxetine, 0.05 for pregabalin, and 0.00 for mexiletine. Conclusions and Relevance This study found that, although there was no clearly superior medication, nortriptyline and duloxetine outperformed pregabalin and mexiletine when pain reduction and undesirable adverse effects are combined to a single end point. Trial Registration ClinicalTrials.gov Identifier:NCT02260388

Peripheral nerve hyperexcitability (PNH) syndromes are divided into primary and secondary groups based on the presence or absence of demonstrable peripheral nerve disease. In this review, we systematically evaluate the evidence for current therapies and supportive managements based on autoimmune, paraneoplastic, and genetic components in pathophysiology reported in the literature. Current therapy options are based on symptomatic management as well as focusing the underlying immune/genetic/paraneoplastic pathology by immunosuppressants, chemotherapy, and surgery. Further research is desired to provide treatment options geared specifically towards addressing PNH. Supportive care can also be an area for future research.

Isaacs syndrome is a peripheral nerve hyperexcitability (PNH) syndrome that presents as continuous motor activity. Clinical findings include cramps, fasciculations, and myokymia. Electrodiagnosis plays a key role in diagnosis by demonstrating after-discharges on nerve conduction studies, and fasciculation potentials, myokymic discharges, neuromyotonic discharges, and other types of abnormal spontaneous activity on needle examination. Etiopathogenesis involves the interaction of genetic, autoimmune, and paraneoplastic factors, which requires a broad-ranging evaluation for underlying causes. Initial treatment is symptomatic, but immune therapy is often needed and can be effective. The purpose of this review is to describe the syndrome and its pathogenesis, assist the reader in evaluating patients with suspected Isaacs syndrome and distinguishing it from other disorders of PNH, and suggest an approach to management, including both symptomatic and immunomodulating therapy.

Background The specialty of Neurology is faced with a fundamental problem of economics: supply and demand. The projected increase in provider supply is unlikely to keep up with projected increases in patient-care demand. Many large academic centers have used residents to meet this patient-care demand. However, the conflict between education of residents and patient-care needs has created a hindrance to both of those missions. Many specialties have been using advanced practice clinicians (APCs) to help address the need for patient care. In the setting of a residency program, this availability of APCs can help to alleviate patient-care demands for the resident and allow for better allocated educational time. Neurology has not historically been a popular choice for APCs and a standardized educational curriculum for a Neurology APC has not been established. Methods The authors share an example curriculum recently implemented for training new inpatient Neurology APCs. This curriculum includes a 12-week program complete with rotations through various subspecialties and proposes fundamental lecture topics for use in education. The authors share their expectations for clinical duties that evolve over the course of the 12-week program in conjunction with expectations for increasing clinical knowledge as well as efficiency in system utilization. Conclusion The addition of APCs to support a busy inpatient Neurology practice has obvious beneficial implications but the integration and education of this new staff must be structured and well-designed to support the confidence of the APC in both their knowledge and their role as an indispensable member of the care team.

Pseudobulbar affect (PBA) may occur in association with a variety of neurological diseases, and so may be encountered in the setting of amyotrophic lateral sclerosis, extrapyramidal and cerebellar disorders, multiple sclerosis, traumatic brain injury, Alzheimer’s disease, stroke, and brain tumors. The psychological consequences and the impact on social interactions may be substantial. Although it is most commonly misidentified as a mood disorder, particularly depression or a bipolar disorder, there are characteristic features that can be recognized clinically or assessed by validated scales, resulting in accurate identification of PBA, and thus permitting proper management and treatment. Mechanistically, PBA is a disinhibition syndrome in which pathways involving serotonin and glutamate are disrupted. This knowledge has permitted effective treatment for many years with antidepressants, particularly tricyclic antidepressants and selective serotonin reuptake inhibitors. A recent therapeutic breakthrough occurred with the approval by the Food and Drug Administration of a dextromethorphan/quinidine combination as being safe and effective for treatment of PBA. Side effect profiles and contraindications differ for the various treatment options, and the clinician must be familiar with these when choosing the best therapy for an individual, particularly elderly patients and those with multiple comorbidities and concomitant medications.

Diabetes is well known to affect peripheral nervous system. We have summarized the multiple different presentations of peripheral nervous system involvement in this disease along with the medical and rehabilitation management. The clinical presentation depends on the localization of the damage which can involve nerve roots, plexus, focal nerves, diffuse involvement of multiple nerves and autonomic system. The process can be acute or insidious based on the pathology which can be variable.

Introduction: Intraneural perineurioma is a rare benign tumor composed of perineural cells. It typically affects teenagers and young adults and tends to present as a gradual onset motor predominant neuropathy. Pain and sensory disturbances are uncommon. Methods: We discuss a case of sciatic perineurioma which was diagnosed with the help of multiple diagnostic modalities including electro diagnostic testing, imaging and biopsy. Results: An electro diagnostic study was done which showed chronic severe left sciatic neuropathy with on-going denervation and MRI of the left lower extremity revealed enlargement and increase signal of the left sciatic nerve. A left sciatic nerve biopsy revealed intraneural perineurioma. Conclusion: Intraneural perineurioma should be included in the differential diagnosis of focal neuropathy in a young adult. Imaging and electro diagnostic studies can be useful to indicate the likely presence of an intraneural neoplasm.

Background: Creutzfeldt-Jakob disease (CJD) is a rare neurodegenerative spongiform encephalopathy. Findings are usually consistent with basal ganglia and frontal lobe destruction. However in certain variants, the clinical and diagnostic findings can differ. This case illustrates the occipital findings of the rare Heidenhain variant of CJD. Methods: We describe the clinical course and radiologic findings of a 65-year-old with the Heidenhain variant of Creutzfeldt-Jakob disease. Diagnostic studies included lumbar puncture, EEG and MRI scans of the brain. Results: This case illustrates the findings of the rare Heidenhain variant of CJD, including prominent changes in MRI and EEG in the occipital region. This was further supported by the positive enolase and 14-3-3 in cerebral spinal fluid. Conclusions: In patients presenting with clinical symptoms of visual disorders of unclear origin presenting with or shortly after psychosis or dementia, this variant of CJD must be considered in the differential diagnosis.

A 50 year old woman with a past medical history of hypertension presented with sudden onset of one-and-a-half syndrome on top of a sub-acute 7th nerve palsy. Her MRI findings showed several contrast enhancing lesions including a pontine lesion. The lumbar puncture (LP) showed oligoclonal bands. Multiple sclerosis (MS) was diagnosed, with the rare initial presentation of eight-and-a-half syndrome. The patient was treated with intravenous steroids, then placed on a disease modifying agent. In this article, we discuss the patient’s imaging and review the pathology of eight-and-a-half syndrome.

The cause of sporadic amyotrophic lateral sclerosis (ALS) is not known. Studies associate toxic, dietary, infectious, neoplastic, and physical factors as underlying, predisposing, or pathogenic influences. Historical, conventional, and novel disease mechanisms, acting solely or in concert, convert previously healthy individuals into terminally ill patients. Despite intensive investigations in the previous decades, the underlying cause and effective treatments elude researchers. Discovering causative mechanisms in sporadic ALS will facilitate effective treatments and cures for this disorder. After a brief review of the disease process itself, this article discusses potential environmental influences on the development of ALS.

Background Common causes of temporal lobe hyper intensities are central nervous system infections like herpes simplex encephalitis, Lyme disease, limbic encephalitis and vascular pathology like Cerebral Autosomal Dominant Arteriopathy with Subcortical infarcts and Leukoencephalopathy. Methods: Personal assessment, laboratory data analysis and neuroimaging for the patient who was admitted to a central Pennsylvania tertiary care referral centre were conducted. Results: A 52-year-old male presented with a 1-year history of diffuse dysesthesia in upper and lower extremities with associated intermittent headaches and neck stiffness. Evaluation with lumbar puncture revealed increased nucleated cells (50 ul) with lymphocytic predominance (96%) and an elevated protein level of 109 mg/dl. Magnetic resonance imaging (MRI) of the brain showed T2/FLAIR hyper intensity in bilateral subcortical temporal white matter, left-greater-than-right and associated volume loss in cerebral parenchyma. Additional abnormal work up included reactive serum reactive plasma regain and Treponema pallidum antibody particle agglutination. Diagnosis of neurosyphilis was made and the patient was treated with intramuscular (IM) penicillin for 3 weeks. At the time of discharge, his headache and neck stiffness resolved and dysesthesias were decreased in intensity. Conclusions: The diagnosis of neurosyphilis is intricate, and no reference standard exists. Neuroimaging findings of neurosyphilis commonly are cerebral infarctions, leptomeningeal enhancement or non-specific white matter lesions. Less common features on fluid-attenuated inversion recovery (FLAIR) sequences are cortical atrophy and mesial temporal parenchymal signal changes. It is prudent to keep neurosyphilis in differential of mesial temporal lobe white matter changes, as early diagnosis and treatment results in better prognosis.

Seizures are followed by a post-ictal period, which is characterized by usual slowing of brain activity. This case report describes a 68-year old woman who presented with right-sided rhythmic, non-voluntary, semi-purposeful motor behavior that started 2 days after an episode of generalized seizure. Her initial electroencephalogram (EEG) showed beta activity with no evidence of epileptiform discharges. Computed tomography scan showed hypodensity in the left parieto-occipital region. Magnetic resonance imaging (MRI) showed restricted diffusion/fluid-attenuated inversion recovery hyperintensities in the left precentral and post-central gyrus. Unilateral compulsive motor behavior during the post-ictal state should be considered, and not confused with partial status epilepticus to avoid unnecessary treatment. Abnormal magnetic resonance imaging (MRI) findings, which are reversible, can help with the diagnostic and therapeutic approach.

BACKGROUND/PURPOSE Leptomeningeal collateral volume flow has not been previously quantified. Quantitative magnetic resonance angiography (QMRA) can determine flow in the large vessels of the intracranial circulation. METHODOLOGY We reviewed consecutive QMRA studies performed between December 1, 2004 and August 30, 2005, for cases showing asymmetrically higher flow in a posterior cerebral artery (PCA) just distal to the origin of the posterior communicating artery ipsilateral to a hemodynamic middle cerebral artery (MCA) or internal carotid artery lesion. The mean, range, and standard deviation (SD) of the flow rate in the PCAs, MCAs, and PCA ipsilateral-contralateral difference were calculated. Ipsilateral and contralateral PCA flow rates were compared using the Student's t-test. RESULT Sixteen studies met selection criteria. Mean age was 52 years (range 21-79) and 9 were female. MCA flow was below QMRA detection limits in 6 studies. Mean measurable ipsilateral MCA flow reduction was 84 mL/min (range 9-147, SD 51.4). Mean ipsilateral PCA flow was 118 mL/min (range 72-206, SD 38.5) and mean contralateral PCA flow was 68 mL/min (range 35-144, SD 30.5, P < .001); mean difference was 50 mL/min (range 10-93, SD 24.3). CONCLUSION Leptomeningeal collateral flow can be assessed with QMRA and may be substantial.

Isaacs syndrome is a peripheral nerve hyperexcitability (PNH) syndrome that presents as continuous motor activity. Clinical findings include cramps, fasciculations, and myokymia. Electrodiagnosis plays a key role in diagnosis by demonstrating after-discharges on nerve conduction studies, and fasciculation potentials, myokymic discharges, neuromyotonic discharges, and other types of abnormal spontaneous activity on needle examination. Etiopathogenesis involves the interaction of genetic, autoimmune, and paraneoplastic factors, which requires a broad-ranging evaluation for underlying causes. Initial treatment is symptomatic, but immune therapy is often needed and can be effective. The purpose of this review is to describe the syndrome and its pathogenesis, assist the reader in evaluating patients with suspected Isaacs syndrome and distinguishing it from other disorders of PNH, and suggest an approach to management, including both symptomatic and immunomodulating therapy.

Opsoclonus-myoclonus syndrome is a rare condition with dyskinesia of eye movements and myoclonic movements of the trunk and limbs. It is linked to malignancies, infections and other conditions. We present a case of post-vaccination opsoclonus-myoclonus syndrome. We believe that our patient also experienced a viral illness post-vaccination and prior to the development of opsoclonus-myoclonus. The vaccination in combination with the viral illness potentiated the immune mechanism thought to be noted in this condition. This was supported by her recovery after receiving immunotherapy.

A patient developed neck extensor weakness along with symmetrical, mild proximal extremity weakness. Electrodiagnostic findings were minimal. Subsequently muscle biopsy was undertaken which showed myopathic changes as well as rimmed vacuoles. This case highlights the discussion of histopatholgical findings seen in neck extensor weakness when it occurs in isolation as well as when it is associated with weakness in other distribution. Keywords Neck extensor weakness; Rimmed vacuoles; Myopathy

Peripheral nerve lesions are common and can present in a variety of ways. Peripheral nerve injury can result from a broad spectrum of causes. For the majority of patients, rehabilitation is generally indicated regardless of etiology. Evaluation and treatment by a multidisciplinary team including neurologists, psychiatrists, surgeons, occupational and physical therapists, and therapists with specialized training in orthotics maximizes the potential for recovery. This chapter will focus on those upper and lower extremity neuropathies that are most commonly seen in clinical practice. In addition, we discuss various rehabilitative strategies designed to improve function and quality of life.

A patient developed numbness and tingling in distal extremities with subsequent weakness. Evaluation revealed B12 deficiency. She had evidence of myelopathy on imaging studies and polyneuropathy on electrodiagnostic testing. Treatment with B12 caused remittance of symptoms and resolution/improvement of abnormalities found on the imaging and electrodiagnostic studies. This case demonstrates that early intervention with B12 supplementation can cause reversal of both central and peripheral nervous system dysfunction.

Meralgia paresthetica consists of pain and dysesthesia in the anterolateral thigh. Etiology is divided into spontaneous and iatrogenic causes. To my knowledge this has never been attributed to femoral acetabular impingement. This case highlights the presence of lateral femoral cutaneous neuropathy in the setting of femoral acetabular impingement syndrome thus raising the possibility of an association. Keywords Femoral acetabular impingement; Lateral femoral cutaneous nerve; Dysesthesia; Nerve conduction studies

Waardenburg syndrome is associated with a variety of clinical features, which may include polyneuropathy. We describe a patient with Waardenburg syndrome type 2 and provide detailed electrodiagnostic findings, thus complementing the biopsy data and brief descriptions of nerve conduction studies found in the literature.

Myoadenylate deaminase deficiency is noted in skeletal muscles. It generally presents with exertional myalgias, fatigue and weakness. We present a patient who complained of constant pain unrelated to activity with biopsy finding consistent of myoadenylate deaminase deficiency. Keywords Myoadenylate deaminase deficiency; Myalgia; Pain

The patient underwent a stereotactic biopsy of the right frontalparietal mass. This showed diffuse large B-cell lymphoma (Fig. 1). He was treated with methotrexate and radiation therapy. The prevalence of primary central nervous system (CNS) lymphoma has increased to 6% among patients with acquired immune deficiency syndrome (AIDS). Unlike classical primary CNS lymphoma, AIDS-related lymphoma can be cortical, tends to involve gray and white matter, is associated with leptomeningeal thickening, and may induce vasculitis. There is predominantly involvement of the basal ganglia, corpus callosum, periventricular white matter, frontal lobes, and thalamus. It is occasionally confined to the subependymal regions or can even be wholly intraventricular. It is typically isointense to gray matter on T2-weighted MRI, usually with a moderate peripheral edema. The isointensity/ hypointensity of the central areas is the result of necrosis due to coagulation necrosis and thrombosis of the vessels. The lesion shows heterogeneous or ring-like, irregular nodular type enhancement. Linear enhancement at the margins of a lesion, tracking along Virchow-Robin perivascular spaces, is highly specific for lymphoma. The major differential diagnosis is toxoplasmosis. Until proven otherwise, patients with HIV/AIDS presenting with focal neurological complaints should be accepted as having CNS toxoplasmosis. The corticomedullary junction, basal ganglia, and thalamus are most frequently involved; less commonly the brainstem may be affected. On T2-weighted MRI, most lesions are hyperintense. The pattern of cryptococcal CNS infection is a solid or ring-like contrast enhancing parenchymal mass (cryptococcoma), which is rare and found preferentially in the ependyma of the choroid plexus. The progressive multifocal leukoencephalopathy lesions are seen typically as hyperintense patchy areas on

The patient had a shunt placed for obstructive hydrocephalus. An endoscopic biopsy of the intraventricular and septal mass was performed which showed findings consistent with a cavernous angioma (Fig. 1). Intracranial vascular malformations are divided into four groups: (i) capillary telangiectasia, (ii) cavernous angioma, (iii) arteriovenous malformation, and (iv) venous malformation. Cavernous angiomas comprise 5% to 13% of all vascular malformations and occur in about 0.5% of the general population. Cerebral cavernous angiomas occur sporadically and in a familial form. Familial cavernous angiomas account for up to 54% of cerebral cavernous angiomas. The most frequent symptoms are seizures, gross intracranial hemorrhages, focal neurological deficits, and migraine-like headaches. The prospective annualized hemorrhage rate calculated on a per-patient basis is 1.6% to 3.1%. Intracranial cavernomas are commonly located in the supratentorial region, brain stem, basal ganglia, and cerebellar hemisphere. On the basis of MRI, four