Listeria monocytogenes brain abscesses presenting as contiguous, tubular rim-enhancing lesions on Magnetic Resonance Imaging: Case series and literature review.

Listeriosis has more than a 50% mortality when the central nervous system is involved, necessitating rapid diagnosis and treatment. We present four patients with brain abscesses in the setting of diagnosed neurolisteriosis, all of which demonstrated an odd presentation of multiple small, contiguous tubular lesions with rim enhancement on magnetic resonance imaging. Our review of published cases of neurolisteriosis suggests that this may be a useful pattern to identify neurolisteriosis abscesses, allowing earlier detection and therapy.

Occipital Nocardia Abscess Presenting With Positive Visual Phenomenon and Quadrantanopsia.

ABSTRACT: A 74-year-old man with chronic obstructive pulmonary disease, glaucoma, and Stage IIIB squamous cell lung cancer experienced several minutes of flashing lights in his right visual hemifield, followed by onset of a right visual field defect. On examination, the patient had a right homonymous hemianopsia that was most dense inferiorly by confrontation testing. Emergent CT scan of the head revealed a 2.5 × 3 cm hypodensity in the left occipital lobe, which was interpreted as an acute stroke. Continuous EEG monitoring captured left posterior quadrant seizures that were temporally correlated to the positive visual phenomena. Subsequent MRI of the brain with and without contrast revealed a conglomerate of centrally necrotic and peripherally enhancing mass lesions. On biopsy, a thick purulent material was drained and Gram stain of the sample revealed gram-positive beaded rods, which speciated to Nocardia farcinica . The patient was treated with a six-week course of intravenous meropenem and a one-year course of oral trimethroprim-sulfamethoxazole. On follow-up, the patient experienced resolution of the right visual field deficit.

Case 299: Sellar Spine.

History Part one of this case appeared 4 months previously and may contain larger images. A 32-year-old woman presented to an ophthalmologist for bilateral blurry vision. She underwent MRI of the brain and orbits, which showed a focal abnormality within the pituitary gland. The patient was referred to an endocrinologist for further evaluation. Review of systems and physical examination by the endocrinologist revealed no symptoms or signs of endocrine dysfunction. Anterior pituitary hormone levels, including growth hormone, prolactin, thyroid stimulating hormone, follicular-stimulating hormone, luteinizing hormone, and adrenocorticotropic hormone, were normal. Dynamic contrast-enhanced MRI of the sella and pituitary gland and subsequent CT of the anterior skull base were performed.

Central Retinal Artery Visualization with Cone-Beam CT Angiography.

Background There are multiple tools available to visualize the retinal and choroidal vasculature of the posterior globe. However, there are currently no reliable in vivo imaging techniques that can visualize the entire retrobulbar course of the retinal and ciliary vessels. Purpose To identify and characterize the central retinal artery (CRA) using cone-beam CT (CBCT) images obtained as part of diagnostic cerebral angiography. Materials and Methods In this retrospective study, patients with catheter DSA performed between October 2019 and October 2020 were included if CBCT angiography included the orbit in the field of view. The CBCT angiography data sets were postprocessed with a small field-of-view volume centered in the posterior globe to a maximum resolution of 0.2 mm. The following were evaluated: CRA origin, CRA course, CRA point of penetration into the optic nerve sheath, bifurcation of the CRA at the papilla, visualization of anatomic variants, and visualization of the central retinal vein. Descriptive statistical analysis was performed. Results Twenty-one patients with 24 visualized orbits were included in the analysis (mean age, 55 years ± 15; 14 women). Indications for angiography were as follows: diagnostic angiography (n = 8), aneurysm treatment (n = 6), or other (n = 7). The CRA was identified in all orbits; the origin, course, point of penetration of the CRA into the optic nerve sheath, and termination in the papilla were visualized in all orbits. The average length of the intraneural segment was 10.6 mm (range, 7-18 mm). The central retinal vein was identified in six of 24 orbits. Conclusion Cone-beam CT, performed during diagnostic angiography, consistently demonstrated the in vivo central retinal artery, demonstrating excellent potential for multiple diagnostic and therapeutic applications. © RSNA, 2021 Online supplemental material is available for this article.

Case 299.

History A 32-year-old woman presented to an ophthalmologist for bilateral blurry vision. She underwent MRI of the brain and orbits, which showed a focal abnormality within the pituitary gland. The patient was referred to an endocrinologist for further evaluation. Review of systems and physical examination by the endocrinologist revealed no symptoms or signs of endocrine dysfunction. Anterior pituitary hormone levels, including growth hormone, prolactin, thyroid stimulating hormone, follicular stimulating hormone, luteinizing hormone, and adrenocorticotropic hormone, were normal. Dynamic contrast-enhanced MRI of the sella and pituitary gland (Figs 1-3) and subsequent CT of the anterior skull base (Figs 4, 5) were performed.

"The Pituitary within GRASP" - Golden-Angle Radial Sparse Parallel Dynamic MRI Technique and Applications to the Pituitary Gland.

MRI is the preferred radiologic modality for evaluating the pituitary gland. An important component of pituitary MRI examinations is dynamic contrast-enhanced MRI. Compared to conventional dynamic techniques, golden-angle radial sparse parallel (GRASP) imaging offers multiple advantages, including the ability to achieve higher spatial and temporal resolution. In this narrative review, we discuss dynamic imaging of the pituitary gland, the technical fundamentals of GRASP, and applications of GRASP to the pituitary gland.

Medical Student Engagement and Educational Value of a Remote Clinical Radiology Learning Environment: Creation of Virtual Read-Out Sessions in Response to the COVID-19 Pandemic.

RATIONALE AND OBJECTIVES: The need for social distancing has resulted in rapid restructuring of medical student education in radiology. While students traditionally spend time learning in the reading room, remote clinical learning requires material shared without direct teaching at the radiology workstation. Can remote clinical learning meet or exceed the educational value of the traditional in-person learning experience? Can student engagement be matched or exceeded in a remote learning environment? MATERIALS AND METHODS: To replace the in-person reading room experience, a small-group learning session for medical students named Virtual Read-Out (VRO) was developed using teleconferencing software. After Institutional Review Board approval, two student groups were anonymously surveyed to assess differences in student engagement and perceived value between learning environments: "Conventional" students participating in the reading room (before the pandemic) and "Remote" students participating in VRO sessions. Students reported perceived frequency of a series of five-point Likert statements. Based on number of respondents, an independent t-test was performed to determine the significance of results between two groups. RESULTS: Twenty-seven conventional and 41 remote students responded. Remote students reported modest but significantly higher frequency of active participation in reviewing radiology exams (p < 0.05). There was significantly lower frequency of reported boredom among Remote students (p < 0.05). There was no significant difference in perceived educational value between the two groups. CONCLUSION: Students report a high degree of teaching quality, clinical relevance, and educational value regardless of remote or in-person learning format. Remote clinical radiology education can be achieved with equal or greater student interaction and perceived value in fewer contact hours than conventional learning in the reading room.

Awake Laser Ablation for Patients With Tumors in Eloquent Brain Areas: Operative Technique and Case Series.

Background Magnetic resonance imaging (MRI)-guided laser interstitial thermal therapy (LITT) is a minimally invasive treatment modality that has been gaining traction in neuro-oncology. Laser ablation is a particularly appealing treatment option when eloquent neurologic function at the tumor location precludes conventional surgical excision. Although typically performed under general anesthesia, LITT in awake patients may help monitor and preserve critical neurologic functions. Objective To describe intraoperative workflow and clinical outcomes in patients undergoing awake laser ablation of brain tumors. Methods We present a cohort of six patients with tumors located in eloquent brain areas that were treated with awake LITT and report three different workflow paradigms involving diagnostic or intraoperative MRI. In all cases, we used NeuroBlate® (Monteris Medical, Plymouth, MN) fiberoptic laser probes for stereotactic laser ablation of tumors. The neurologic status of patients was intermittently assessed every few minutes during the ablation. Results The mean preoperative tumor volume that was targeted was 12.09 ± 3.20 cm3, and the estimated ablation volume was 12.06 ± 2.75 cm3. Performing the procedure in awake patients allowed us close monitoring of neurologic function intraoperatively. There were no surgical complications. The length of stay was one day for all patients except one. Three patients experienced acute or delayed worsening of pre-existing neurologic deficits that responded to corticosteroids. Conclusion We propose that awake LITT is a safe approach when tumors in eloquent brain areas are considered for laser ablation.

Imaging of Spine Trauma.

Every year in North America, approximately 3 million patients are evaluated for spinal injury. Of blunt trauma patients presenting to the emergency department, 3% to 4% will have a cervical spine injury, and up to 18% will suffer a thoracolumbar spine injury. Failure to identify an unstable spine injury can lead to devastating outcomes.