Construction of a Machine Learning Dataset through Collaboration: The RSNA 2019 Brain CT Hemorrhage Challenge.

This dataset is composed of annotations of the five hemorrhage subtypes (subarachnoid, intraventricular, subdural, epidural, and intraparenchymal hemorrhage) typically encountered at brain CT.

Erratum: Construction of a Machine Learning Dataset through Collaboration: The RSNA 2019 Brain CT Hemorrhage Challenge.

[This corrects the article DOI: 10.1148/ryai.2020190211.].

Herpes zoster ophthalmicus caught in the (Tr)act!

To emphasize the utility of contrast enhanced MRI for identifying the extent of disease in herpes zoster ophthalmicus with intracranial extension to help determine proper management. We present a rare case of herpes zoster ophthalmicus (HZ/HZO) with intracranial extension and MRI demonstration of involvement of the trigeminal nerve, the trigeminal nucleus, and the spinal trigeminal nucleus and tract. Herpes zoster is caused by reactivation of varicella zoster virus. Herpes zoster ophthalmicus with involvement of the ophthalmic division of the trigeminal nerve has been estimated to account for 10-20% of the cases (Yawn et al. in Mayo Clin Proc 88:562-570, 2013). While postherpetic neuralgia is the most common complication, HZ/HZO can rarely manifest in a more sinister manner resulting in multi-dermatomal involvement, disseminated disease, cranial arteritis (Walker in Radiology 107:109-110, 1973), cranial nerve paresis (O.d in Clinical Eye and Vision Care 11:75-80, 1999), hemiplegia (Cavaletti in The Italian Journal of Neurological Sciences 11:297-300, 1990), ocular/dysfunction (Kocaoglu in Türk Oftalmoloji Dergisi 48:42-46, 2018), and intracranial extension (Chen in BMC Infectious Diseases 17:213, 2017; Yawn in Mayo Clin Proc. 88:562-570, 2013). Contrast enhanced MRI (CE-MRI) can be of great benefit to elucidate the extent of disease and intracranial involvement for institution of more aggressive management to prevent further complications.

Contrast-Induced Neurotoxicity following Cardiac Catheterization.

We report a case of probable contrast-induced neurotoxicity that followed a technically challenging cardiac catheterization in a 69-year-old woman. The procedure had involved the administration of a large cumulative dose of an iodinated, nonionic contrast medium into the innominate artery: twelve hours following the catheterization, the patient developed a seizure followed by a left hemiplegia, and an initial computed tomography (CT) scan showed sulcal effacement in the right cerebral hemisphere due to cerebral swelling. The patient's clinical symptoms resolved within 24 hours, and magnetic resonance imaging at 32 hours showed resolution of swelling. Contrast-induced neurotoxicity should be found in the differential diagnosis of acute neurological deficits occurring after radiological procedures involving iodinated contrast media, whether ionic or nonionic.

Choroid plexitis in a case of systemic nocardiosis.

Although rare, primary choroid plexitis can occur as an early presentation of a central nervous system (CNS) infection most commonly with cryptococcosis, tuberculosis, and nocardiosis. In the appropriate clinical setting, an enlarged, intensely enhancing choroid plexus should raise suspicion for choroid plexitis. It is important to recognize this entity early as aggressive diagnostic and therapeutic intervention may be necessary. We review the existing literature and present a case of infectious choroid plexitis in a patient with systemic nocardiosis; computed tomography and magnetic resonance imaging demonstrated the characteristic findings of choroid plexitis, which later developed into a parenchymal abscess.

Radiological and pathological changes in hemiballism-hemichorea with striatal hyperintensity.

We report CT and MRI findings in a 50-year-old African-American woman with hemichorea-hemiballism (HCHB) and hyperglycemia with striatal hyperintensity. Histopathologic findings following autopsy are also described, and possible explanations for the MR findings of this unique syndrome are presented.

The earliest manifestation of focal encephalitis on diffusion-weighted MRI.

We report the case of an adult patient with a focus of meningioencephalitis in whom the earliest magnetic resonance imaging (MRI) manifestation was hyperintense signal on diffusion-weighted (DW) sequence only. To our knowledge, this is the first adult encephalitis case to be reported with the MRI diffusion-weighted pulse sequence being the only positive MRI finding. A brief review of the pertinent literature is included.

MRI findings of vestibulocochlear hemorrhage in a leukemic patient with sensorineural hearing loss.

This case report presents a patient with M4 leukemia with signs and symptoms of acute sensorineural hearing loss. The patient's MRI demonstrated high signal on unenhanced T1-weighted images within the left vestibulocochlear complex that was consistent with subacute hemorrhage. Follow-up MRI showed clearing of the previously seen high T1-weighted signal from the left vestibulocochlear complex. This case report documents for the first time the MRI findings of vestibulocochlear complex hemorrhage in a leukemic patient.