Case 324: CHANTER Syndrome.

HISTORY: A 69-year-old right-handed man with a history of substance use disorder, hypertension, and diabetes presented to the emergency department in an unresponsive state. Upon examination, apart from tachycardia (heart rate, 108 beats per minute), vital signs were within normal ranges (blood pressure, 134/102 mm Hg; temperature, 97.9 ºF (36.6 ºC); respiratory rate, 16 per minute; oxygen saturation, 96%). The patient had a Glasgow coma scale score of 8. Otherwise, the physical examination revealed no abnormalities. Prior psychiatric and surgical histories were unremarkable. There was no history of recent travel, camping, hiking, or vaccination. No family history could be obtained. Laboratory work-up revealed an elevated creatine kinase level (49 006 U/L [818.4 µkat/L]; normal reference range, 10-205 U/L [0.17-3.42 µkat/L]). An electrocardiogram showed sinus tachycardia without evidence of cardiac ischemia. An echocardiogram was unremarkable. Alanine aminotransferase (126 U/L [2.10 µkat/L]; normal reference range, 0-40 U/L [0-0.67 µkat/L]) and aspartate aminotransferase (488 U/L [8.15 µkat/L]; normal reference range, 3-44 U/L [0.05-0.74 µkat/L]) levels were elevated. Polymerase chain reaction results were negative for HIV-1, HIV-2, syphilis treponemal, and COVID-19 antibodies. The remaining routine laboratory work-up findings were within normal limits. Urine drug screening was positive for cocaine, marijuana, fentanyl, and benzodiazepines. Naloxone was administered, but the patient remained unresponsive. Intubation was performed for airway protection. Noncontrast and contrast-enhanced CT of the head and CT angiography were performed in the emergency department to rule out an acute intracranial abnormality. Multisequence MRI of the brain with administration of intravenous contrast material was ordered for further assessment. CT of the abdomen and pelvis was unremarkable (images not shown).

Case 313.

HISTORY: A 45-year-old woman presented to the emergency department of an outside hospital with shortness of breath and cough. Five days after initial presentation, the patient presented again to the same emergency department with worsening headache and progressive left arm and left leg weakness. She was transferred to the neuroscience intensive care unit of our hospital with concern for an intracranial abnormality based on her work-up at the outside hospital. Her past medical history was notable only for a large uterine fibroid. In our hospital, CT of the brain and chest (Figs 1, 2) and MRI of the brain, including perfusion studies (Figs 3, 4), were performed. Additionally, CT venography of the brain was performed (Fig 5).

Case 313: Cerebral Venous Infarct Due to Internal Cerebral Vein Thrombosis in the Setting of COVID-19 Infection.

HISTORY: A 45-year-old woman presented to the emergency department of an outside hospital with shortness of breath and cough. Five days after initial presentation, the patient presented again to the same emergency department with worsening headache and progressive left arm and left leg weakness. She was transferred to the neuroscience intensive care unit of our hospital with concern for an intracranial abnormality based on her work-up at the outside hospital. Her past medical history was notable only for a large uterine fibroid. In our hospital, CT of the brain and chest and MRI of the brain, including perfusion studies, were performed. Additionally, CT venography of the brain was performed.

Case 324.

HISTORY: A 69-year-old right-handed man with a history of substance use disorder, hypertension, and diabetes presented to the emergency department in an unresponsive state. Upon examination, apart from tachycardia (heart rate, 108 beats per minute), vital signs were within normal ranges (blood pressure, 134/102 mm Hg; temperature, 97.9°F [36.6°C]; respiratory rate, 16 breaths per minute; oxygen saturation, 96%). He had a Glasgow coma scale score of 8. Otherwise, the physical examination revealed no abnormalities. His prior psychiatric and surgical histories were unremarkable. There was no history of recent travel, camping, hiking, or vaccination. No family history could be obtained. Laboratory work-up revealed an elevated creatine kinase level (49 006 U/L [818.4 µkat/L]; normal reference range, 10-205 U/L [0.17-3.42 µkat/L]). An electrocardiogram showed sinus tachycardia without evidence of cardiac ischemia. An echocardiogram was unremarkable. Alanine aminotransferase (126 U/L [2.10 µkat/L]; normal reference range, 0-40 U/L [0-0.67 µkat/L]) and aspartate aminotransferase (488 U/L [8.15 µkat/L]; normal reference range, 3-44 U/L [0.05-0.74 µkat/L]) levels were elevated. Polymerase chain reaction results were negative for HIV-1, HIV-2, syphilis treponemal, and COVID-19 antibodies. The rest of the routine laboratory work-up findings were within normal limits. Urine drug screening was positive for cocaine, marijuana, fentanyl, and benzodiazepines. Naloxone was administered, but the patient remained unresponsive. Intubation was performed for airway protection. Noncontrast and contrast-enhanced CT of the head (Fig 1) and CT angiography were performed in the emergency department to rule out an acute intracranial abnormality. Multisequence MRI of the brain with administration of intravenous contrast material was ordered for further assessment (Figs 2-4). CT of the abdomen and pelvis was unremarkable (images not shown).

The significance of automatically measured transient ischemic dilation in identifying severe and extensive coronary artery disease in regadenoson, single-isotope technetium-99m myocardial perfusion SPECT.

BACKGROUND: The critical threshold and clinical significance of transient ischemic dilation (TID) for regadenoson, single-isotope (99m)Tc SPECT myocardial perfusion imaging (MPI) are not defined. METHODS: From 100 patients with low likelihood of CAD, we derived the abnormal TID threshold (mean + 2 SD). We validated the threshold in a cohort of 547 patients who received one-day, rest/regadenoson-stress, (99m)Tc-tetrofosmin SPECT-MPI followed by coronary angiography within 6 months. Patients were classified into three CAD severity strata: no significant CAD, mild to moderate CAD, and severe and extensive CAD. RESULTS: The abnormal TID threshold was determined to be 1.31. Though mean TID ratios were different between the three CAD severity groups and the derivation cohort (P < .001), there was no difference in the mean TID ratios between the categories of CAD severity or in the prevalence of severe CAD between TID+ and TID- groups (P = .74). By ROC analysis, TID had a poor discriminatory capacity in identifying severe and extensive CAD [AUC of 0.55 (95% CI 0.47-0.62, P = .25)]. Stepwise multivariate logistic analysis demonstrated that adding TID to clinical and perfusion data did not provide incremental diagnostic value (P = .87). CONCLUSIONS: The clinical utility of TID with regadenoson-stress MPI in this era of declining CAD burden is questionable.

Imaging review of the atypical spinal epidural space pathologies.

Pathologies affecting the spinal epidural space (SES) comprise various abnormalities. However, they all have the potential to cause thecal sac narrowing or spinal cord compression. In this review, we group these pathologies into degenerative, infective, neoplastic, vascular, traumatic, and others, focusing on their imaging features. Degenerative pathologies of the SES range from disc to facet disease, with a particular emphasis on the less common degenerative pathologies in this review. Infective pathologies affecting the epidural space include spondylodiscitis and associated epidural phlegmon and abscess. Neoplasms arising from typical SES components include neurofibroma, hemangioma, and liposarcoma. MRI is the best modality to assess the anatomy and abnormalities of the epidural space. MRI, combined with computed tomography, or a radiograph, is useful for the evaluation of bones or radiopaque foreign bodies.

Artificial Intelligence (AI) in Radiology: A Deep Dive Into ChatGPT 4.0's Accuracy with the American Journal of Neuroradiology's (AJNR) "Case of the Month".

The advent of artificial intelligence (AI), particularly large language models (LLMs) such as ChatGPT 4.0, holds significant potential in healthcare, specifically in radiology. This study examined the accuracy of ChatGPT 4.0 (July 20, 2023, version) in solving diagnostic quizzes from the American Journal of Neuroradiology's (AJNR) "Case of the Month." We evaluated the diagnostic accuracy of ChatGPT 4.0 when provided with a patient's history and imaging findings weekly over four weeks, using 140 cases from the AJNR "Case of the Month" portal (from November 2011 to July 2023). The overall diagnostic accuracy was found to be 57.86% (81 out of 140 cases). The diagnostic performance varied across brain, head and neck, and spine subgroups, with accuracy rates of 54.65%, 67.65%, and 55.0%, respectively. These findings suggest that AI models such as ChatGPT 4.0 could serve as useful adjuncts in radiological diagnostics, thus potentially enhancing patient care and revolutionizing medical education.

Recurrent Painful Ophthalmoplegic Neuropathy in an Adult Patient: A Case Report With Literature Review.

Recurrent painful ophthalmoplegic neuropathy (RPON), previously known as ophthalmoplegic migraine, is a rare disease that predominantly affects children. Recurrent episodes of ocular cranial nerve paresis with ipsilateral headache characterize this disorder. Diagnosis is mainly clinical with imaging being used as an adjunct. The pathophysiology of the disease is unknown. We present here a case of RPON in a 50-year-old female presenting with multiple episodes of headache and diplopia with associated transient thickening and enhancement of the ipsilateral oculomotor nerve on magnetic resonance imaging (MRI).

Leptomeningeal Carcinomatosis Mimicking Reversible Cerebral Vasoconstriction Syndrome.

Leptomeningeal carcinomatosis is the result of metastatic infiltration of the leptomeninges by malignant cells originating from an extra-meningeal primary tumor site. We describe a patient with active breast cancer who presented with thunderclap headaches (THs) and imaging showing multi-segment irregular arterial narrowing of intracranial vasculature. A 58-year-old Caucasian woman with active stage IV estrogen receptor-positive breast adenocarcinoma and migraine presented with THs. Computed tomography and brain magnetic resonance imaging (MRI) without contrast were unremarkable. Over a period of one week, she had recurrent THs. Interval vessel imaging showed multi-segment irregular arterial narrowing. Treatment with verapamil was initiated for suspected reversible cerebral vasoconstriction syndrome (RCVS). She subsequently had two discrete episodes of confusion with aphasia and left upper extremity numbness. Repeat gadolinium-enhanced MRI showed nodular leptomeningeal enhancement. Lumbar puncture revealed malignant cells in the cerebrospinal fluid consistent with leptomeningeal carcinomatosis. She subsequently underwent whole brain radiation treatment and intrathecal chemotherapy and had no further episodes of TH. Our case emphasizes the importance of considering leptomeningeal carcinomatosis in the differential diagnosis of THs and reversible cerebral vasculopathy, especially in patients with known underlying active cancer. The illustration also proves the importance of a complete work-up in patients with known malignancy in the setting of suspected RCVS.

Therapeutic response to radiofrequency ablation of neoplastic lesions: FDG PET/CT findings.

Ablation of neoplastic lesions by using radiofrequency energy is gaining popularity in clinical practice because of the minimally invasive nature of radiofrequency ablation (RFA). Primary and secondary tumors of the liver and lung are treated with RFA when surgery is precluded because of comorbidity. Benign bone tumors are also treated with RFA to relieve pain and prevent further tumor growth. Differentiation between postablation tissue changes and residual disease is difficult with morphologic imaging modalities such as ultrasonography, computed tomography (CT), and magnetic resonance (MR) imaging, thus limiting the use of these modalities to detection of residual disease early after RFA. Fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) is a functional imaging modality that can be used to study the effects and efficacy of RFA. Lesions that show increased FDG uptake at PET become completely photopenic immediately after RFA, a finding that is suggestive of the completeness of ablation. Focal areas of increased FDG uptake within the ablated zone are suggestive of residual disease. Reactive tissue changes such as inflammation are depicted in the periphery of the ablated lesion and show a uniform low-grade FDG uptake, which can be differentiated from the focal, nodular intense uptake in areas of residual disease. Use of combined FDG PET/CT to detect residual disease early after RFA allows ablation to be repeated, if necessary, to obtain the maximum therapeutic benefit. Note that FDG uptake in the complications sometimes associated with RFA can be a cause of potential false-positive PET results.

Imaging Evaluation of the Spinal Hardware: What Residents and Fellows Need to Know.

We provide a comprehensive review of the purpose and expected imaging findings of different types of spinal instrumentation. We also demonstrate the imaging evaluation for optimal positioning and assessment of hardware failure.

Enlargement of Dorello's Canal as a Novel Radiographic Marker of Idiopathic Intracranial Hypertension.

Objectives The objective of this study is to compare the visibility and size of Dorello's canal (DC) on magnetic resonance imaging between patients with idiopathic intracranial hypertension (IIH) and control patients, for its evaluation as a potential novel marker for chronic increased intracranial pressure (ICP). Design Retrospective blinded case-control study. Setting Tertiary care academic center. Participants Fourteen patients with spontaneous cerebrospinal fluid (CSF) rhinorrhea and diagnosed IIH, as well as an equal number of age and gender-matched controls. Main Outcome Measures Radiographic presence or absence of visible CSF sleeve within DC as well as CSF sleeve width when present. Results Following review of 28 IIH canals and 28 control canals, IIH patients were significantly more likely to have a visible CSF sleeve within DC and to have a wider measured medial entrance to DC ( p < 0.001). Conclusion Identification of CSF evagination into DC may serve as a reliable marker for increased ICP in the IIH population. This finding should be considered in the future as paradigms for diagnosis of IIH continue to evolve.

Dural Ectasia and Cauda Equina Syndrome: A Rare Complication of Long-standing Fusion.

The clinicoradiological combination of cauda equina syndrome (CES) and dural ectasia is rare and has been described in a few of patients with ankylosing spondylitis (AS). Simultaneous occurrence of these entities in the absence of AS and in patients with long-standing spinal fusion is extremely rare. We present a case of dural ectasia and CES occurring as a long-term complication of instrumented spinal fusion and discuss the pathogenesis, imaging findings, and management options of this elusive disease process.

Eccentric, mature osseous cap: A distinct imaging feature of sinonasal osteoblastoma.

BACKGROUND: With the exception of osteomas, bone neoplasms that originate in the sinonasal cavity are seldom diagnosed on preoperative imaging due to a lack of characteristic radiographic features. Here we described the unusual occurrence of an osteoblastoma in the paranasal sinuses, and we drew focus to its salient imaging features. A highly unique imaging sign was indicated, and its pathologic basis was explained, with concurrent review of the literature. METHODS: Case series and review of the literature. RESULTS: Two cases of sinonasal osteoblastoma were managed by definitive surgical resection. Both tumors on preoperative computed tomography demonstrated an expansile, heterogeneous fibro-osseous lesion with an eccentric, mature osseous cap. The dense osseous cap seen on imaging corresponded to a rim of mature bone on histopathology. A review of existing literature revealed the presence of this imaging sign in all reported cases. CONCLUSION: Sinonasal osteoblastoma is an extremely rare entity with undefined imaging characteristics to guide preoperative decision-making. Here we reported, to our knowledge, the first description of a characteristic imaging sign of an eccentric, mature osseous cap, which corresponded histologically to a single peripheral layer rim of osteoblasts, a unique trait of osteoblastoma.

Isolated Extracranial Vasospasm and Intracranial Dissection: An Unusual Imaging Manifestation of Reversible Cerebral Vasoconstriction Syndrome.

Reversible cerebral vasoconstriction syndrome (RCVS) is a distinct clinical syndrome characterized by thunderclap headache and reversible cerebral vasoconstriction. An association between RCVS and arterial dissection has emerged in recent years, where dissection typically involves the cervical vertebral arteries. In this vignette, we describe isolated reversible vasoconstriction, involving the extracranial arteries and intracranial dissection-a combination hitherto never reported.

MR imaging in nelarabine-induced myelopathy.

Nelarabine is one of the newer and novel drugs approved by the USA Food and Drug Administration for treatment of relapsed and resistant acute lymphoblastic leukemia. Although there are a few accounts of the neurologic toxicity of nelarabine in the oncological literature, it has never been discussed from a radiologic stand point to our knowledge. We describe a case of nelarabine-induced myelopathy and review the existing literature in an attempt to characterize the MRI features helpful in making an early diagnosis of this elusive entity.