Joan E. Maley

MR imaging of pituitary morphology in idiopathic intracranial hypertension.

The aim of this study was to investigate the morphologic changes of the pituitary gland in patients with the clinical diagnosis of idiopathic intracranial hypertension (IIH). Qualitative and quantitative analyses of pituitary morphology were performed in normal subjects (n = 23), patients with the clinical diagnosis of IIH (n = 40), and patients with acute increased intracranial pressure (AICP; n = 37) caused by acute head trauma. The loss of pituitary height (concavity) on the sagittal T1‐weighted image was classified into five categories: I = normal, II = superior concavity that was mild (<⅓ the height of the sella), III = moderate (between ⅓ and ⅔ concavity of height of sella), IV = severe (>⅔ concavity of height of sella), and V = empty sella. The area ratio of pituitary gland to sella turcica measured in the midsagittal plane was quantified. Clinical records were retrospectively reviewed to correlate with magnetic resonance (MR) findings. Using moderate concavity (>⅓) as the minimum criterion for abnormality, IIH patients had an 85% incidence of morphologic changes with 80% sensitivity and 92% specificity. Empty sella (almost complete concavity of the sella) was found in only 2.5% of patients with IIH. Quantitative analysis of the pituitary gland/sella turcica area ratio showed a significant decrease in patients with IIH (P < 0.0001) but no significant difference between the normal subjects and AICP patients. A posterior deviation of the pituitary stalk was seen in 43% of patients. No enlargement of the ventricles or sulcal effacement was seen in IIH patients. Routine brain MR examination of patients with IIH frequently shows morphologic changes of the pituitary gland ranging from various degrees of concavity to (rarely) the extreme case of an empty sella. The etiology is unknown and may be related to the severity and duration of elevated CSF pressure. Such findings may be useful to facilitate the diagnosis of IIH, particularly in patients with equivocal clinical findings or when IIH is not suspected. J. Magn. Reson. Imaging 2000;12:808–813.

Diagnosis of microvasculopathy in CNS vasculitis: value of perfusion and diffusion imaging.

Functional imaging may come to play an important role in the evaluation of CNS vasculitis by demonstrating pathology on the microcirculatory level. A positive finding of microvascular ischemia may assist in the diagnosis of CNS vasculitis. More importantly, the demonstration of normal microcirculation may reliably exclude CNS vasculitis. J. Magn. Reson. Imaging 1999;10:310–313.

Radiographic association of schwannomas with sensory ganglia.

Objective Clinical experience suggests that the majority of schwannomas arise within sensory ganglia, suggesting that intraganglionic glial cells represent a potential cell of origin for schwannomas. To support this clinical impression, we reviewed magnetic resonance imaging (MRI) studies performed over a 5-year period at our institution to determine the relationship of cranial and spinal nerve schwannomas with the ganglia of the associated nerves. Study design Retrospective cohort study. Setting Tertiary referral center. Patients Patients undergoing imaging study at our institution over a 5-year period. Intervention(s) Radiographic images at our institution were reviewed as well as published studies to determine the anatomic location of schwannomas. Main Outcome Measure(s) Anatomic location of schwannomas. Results A total of 372 patients were found over the 5-year study period, 31 of those were diagnosed with neurofibromatosis Type 2 (NF2). Vestibular schwannomas comprised the greatest number of schwannomas, followed by spinal schwannomas. In NF2 patients, spinal schwannomas were the most common tumor, followed by vestibular schwannomas. In NF2 patients and those with sporadic schwannomas, the overwhelming majority of tumors arose in nerves with a sensory component and were associated with the sensory ganglia of the nerves (562/607, 92.6%). Very few tumors arose from pure motor nerves. This is supported by review of published articles on anatomic location of schwannomas. Conclusion Schwannomas are strongly associated anatomically with the ganglia of sensory nerves. These findings raise the possibility that intraganglionic glial cells give rise to the majority of schwannomas.

Current and future imaging of acute cerebral ischemia: assessment of tissue viability by perfusion imaging.

With the advances and availability of new imaging modalities, the role of imaging of acute stroke has been broadened from making diagnosis to providing valuable information for patient management. We need to have rapid diagnostic modalities that distinguish reversible ischemic tissue from irreversibly damaged tissue for successful thrombolytic therapy. Although diffusion imaging has been reported to have both high sensitivity and specificity for acute ischemia in clinical studies, previous reports do not conclude whether the diffusion abnormality is indicative of reversibly or irreversibly injured tissue. Perfusion imaging such as perfusion magnetic resonance imaging and single-photon emission computed tomography may have the potential for providing useful information that determines tissue viability and/or reversibility. Cerebral blood flow thresholds evaluated by pretreatment single-photon emission computed tomography provide important information that is potentially useful in the management of acute stroke patients with intra-arterial thrombolysis. Perfusion imaging, when combined with diffusion imaging, may thus be potentially useful in improving patient selection for thrombolytic therapy.

Automatic retrieval of bone fracture knowledge using natural language processing.

Natural language processing (NLP) techniques to extract data from unstructured text into formal computer representations are valuable for creating robust, scalable methods to mine data in medical documents and radiology reports. As voice recognition (VR) becomes more prevalent in radiology practice, there is opportunity for implementing NLP in real time for decision-support applications such as context-aware information retrieval. For example, as the radiologist dictates a report, an NLP algorithm can extract concepts from the text and retrieve relevant classification or diagnosis criteria or calculate disease probability. NLP can work in parallel with VR to potentially facilitate evidence-based reporting (for example, automatically retrieving the Bosniak classification when the radiologist describes a kidney cyst). For these reasons, we developed and validated an NLP system which extracts fracture and anatomy concepts from unstructured text and retrieves relevant bone fracture knowledge. We implement our NLP in an HTML5 web application to demonstrate a proof-of-concept feedback NLP system which retrieves bone fracture knowledge in real time.

Pseudo-subarachnoid hemorrhage and cortical visual impairment as the presenting sign of gliomatosis cerebri

A 49-year-old white male presented with a pseudo-subarachnoid hemorrhage and diffuse brain edema. Neuroimaging showed brain edema causing the unusual findings of a pseudo-subarachnoid hemorrhage and bilateral occipital lobe infarcts following herniation and compression of the posterior cerebral arteries. An enlarged corpus callosum was noted which led to a brain biopsy and a diagnosis of gliomatosis cerebri.

Request form history, clinical indication, and yield of brain magnetic resonance studies

To investigate whether improved clinical history allows the radiologist to better predict the pretest probability of obtaining a positive or negative result from a magnetic resonance (MR) examination.

Diagnosis of small vestibular schwannomas using constructive interference steady state sequence: Vestibular Schwannomas Diagnosis Using CISS

The objectives of this study were to evaluate the diagnostic accuracy of constructive interference steady state (CISS) sequencing compared to gadolinium‐enhanced T1 (GdT1) magnetic resonance imaging (MRI) to screen for small vestibular schwannomas (VSs), and to assess the overall diagnostic confidence of neuroradiologists in their ability to accurately diagnose or rule out VSs using CISS imaging compared to a GdT1 MRI

Radiocontrast Dye Extravasation During Sialography

Objective: Evaluate the pathophysiology of contrast extravasation. Methods: Two hundred fifty-five sialograms at the University of Iowa from 2008 to 2016 were reviewed. Results: Twelve sialograms (4.7% of total) were identified with main ductal extravasation. In each case, ductal stenosis as a diagnosis was supported by clinical history and the finding of difficulty in advancing the cannula into the duct during sialography. In all but 1 case, extravasation occurred at the distal duct with no further imaging of the ductal system. Each of the 5 cases treated with sialendoscopy with or without gland resection confirmed stenosis. Ultrasound evaluation of 5 of the cases detected ductal dilation in 4 (80%). Six of 11 computed tomography scans done before the sialogram were interpreted as normal with indirect evidence for ductal stenosis (duct dilation) reported in only 1. All extravasations were associated with either stricture alone or stricture with stone (1 case). Conclusion: Radiocontrast extravasation from the main duct during sialography is highly associated with the presence of ductal stricture. In our experience, the inability to fill the ductal system with radiocontrast is a useful sialographic finding that correlated closely with anatomic abnormality rather than technical error. The frequent finding of extravasation of radiocontrast supports the use of water soluble contrast.

Ectopic mediastinal parathyroid adenoma localized with four-dimensional CT: a case report

We present a case of an ectopic mediastinal parathyroid adenoma in a 58-year-old male patient. We show how different imaging modalities were successfully used to reach a diagnosis. We particularly focus on the role of four-dimensional CT scan in preoperative localization of ectopic adenomas and discuss how diverse imaging modalities can be integrated in the workup of ectopic parathyroid adenomas.