Functional Anatomy of the Spinal Cord.

Localization of lesions in the spinal cord requires knowledge of the functional anatomy of gray and white matter tracts. Using decussation points for white matter tracts can help determine lesion level. Pathologies can affect gray and white matter tracts in distinct ways and pattern recognition can help narrow down the differential diagnosis.

Focused Abbreviated Survey MRI Protocols for Brain and Spine Imaging.

There has been extensive growth in both the technical development and the clinical applications of MRI, establishing this modality as one of the most powerful diagnostic imaging tools. However, long examination and image interpretation times still limit the application of MRI, especially in emergent clinical settings. Rapid and abbreviated MRI protocols have been developed as alternatives to standard MRI, with reduced imaging times, and in some cases limited numbers of sequences, to more efficiently answer specific clinical questions. A group of rapid MRI protocols used at the authors' institution, referred to as FAST (focused abbreviated survey techniques), are designed to include or exclude emergent or urgent conditions or screen for specific entities. These FAST protocols provide adequate diagnostic image quality with use of accelerated approaches to produce imaging studies faster than traditional methods. FAST protocols have become critical diagnostic screening tools at the authors' institution, allowing confident and efficient confirmation or exclusion of actionable findings. The techniques commonly used to reduce imaging times, the imaging protocols used at the authors' institution, and future directions in FAST imaging are reviewed to provide a practical and comprehensive overview of FAST MRI for practicing neuroradiologists. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

ACGME Diagnostic Radiology Milestones 2.0: the Time is Now.

The Accreditation Council for Graduate Medical Education oversees graduate medical education in the United States. Designed to provide broad based training in all aspects of imaging, the diagnostic radiology residency program must provide educational experiences that not only provide technical, professional, and patient centered training, but also meet accreditation standards. With the breadth of material to cover during training, carefully orchestrated educational experiences must be planned. This manuscript offers residency program leaders resources to meet the challenges of the new Accreditation Council for Graduate Medical Education Diagnostic Radiology Milestones 2.0 and highlights potential opportunities for future educational endeavors.

Predictors of dysphagia in critically injured patients with neck trauma.

PURPOSE: Trauma patients admitted to the intensive care unit (ICU) are at heightened risk for oropharyngeal dysphagia and pulmonary aspiration. Timely and appropriate referrals for dysphagia may reduce mortality rates and hospital readmissions. This study sought to identify predictors of dysphagia in a large cohort of patients with multiple traumatic injuries. METHODS: The Trauma Registry Database was queried for admissions at a level 1 trauma center from 2012 to 2016 who underwent instrumental swallowing evaluations. Relevant demographics, injuries, and interventions known to be associated with dysphagia were collected. The Dysphagia Outcome and Severity Scale (DOSS) was utilized to define severity of dysphagia. Regression analyses were performed to identify predictors of dysphagia. RESULTS: Two hundred and sixty two patients met criteria. Multivariate analyses found injury severity (p<0.01), tracheostomy (p<0.05), TBI (p<0.05), and cervical spinal bracing (p<0.001) to be predictors of dysphagia development. Furthermore, length of ICU stay (p<0.01) and cervical spinal bracing (p<0.01) were associated with a greater severity of dysphagia. CONCLUSIONS: Oropharyngeal dysphagia is a common complication in trauma patients. Our results propose a set of predictors that should be considered when identifying critically injured patients at risk for dysphagia.

Use of chemical shift encoded magnetic resonance imaging (CSE-MRI) for high resolution fat-suppressed imaging of the brachial and lumbosacral plexuses.

PURPOSE: In the era of increasingly complex surgical techniques for peripheral nerve repair, there is a need for high spatial resolution imaging of the neural plexuses in the body. We describe our experience with chemical shift encoded MRI and its implications for patient management. MATERIALS AND METHODS: IDEAL water-fat separation is a chemical shift based method of homogeneously suppressing signal from fat, while maintaining adequate signal. This technique was used in clinical practice and the patient images reviewed. RESULTS: IDEAL water-fat separation was shown to improve visualization of the brachial and lumbosacral plexuses with good fat suppression and high signal to noise ratio. CONCLUSION: IDEAL water - fat separation is an excellent technique to use in the imaging of the brachial and lumbosacral plexuses as it balances the need for homogeneous fat suppression with maintenance of excellent signal to noise ratio.

Vertebral artery dissection in evolution found during chiropractic examination.

A 30-year-old woman presented to an emergency department with sudden onset of transient loss of left peripheral vision. Owing to a history of migraine headaches, she was released with a diagnosis of ocular migraine. Two days later, she sought chiropractic care for the chief symptom of severe neck pain. The chiropractor suspected the possibility of vertebral artery dissection (VAD). No manipulation was performed; instead, MR angiography (MRA) of the neck was obtained, which revealed an acute left VAD with early thrombus formation. The patient was placed on aspirin therapy. Repeat MRA of the neck 3 months later revealed resolution of the thrombus, without progression to stroke. This case illustrates the importance for all healthcare providers who see patients with neck pain and headache to be attentive to the symptomatic presentation of possible VAD in progress.

Imaging approach to the cord T2 hyperintensity (myelopathy).

In clinically suspected cases of myelopathy, magnetic resonance imaging without and with gadolinium remains the modality of choice. The first and best imaging approach in the evaluation of myelopathy is to identify whether the cause of myelopathy is compressive or noncompressive. The commonest imaging finding in myelopathy is either focal or diffuse cord hyperintensity on the T2-weighted magnetic resonance images. Detailed clinical history, acuity of symptoms (acute vs insidious onset), distribution of the signal abnormalities, including length of cord involvement, specific tract involvement, and the region of the spinal cord that is affected, are very useful in making the diagnosis.

Residents' perception of a novel end-of-rotation evaluation method.

RATIONALE AND OBJECTIVES: With the advent of the new core and certifying examinations, a need has arisen to restructure learning and assessment to better reflect the emphasis on continuous learning throughout residency. We developed a multiparametric end-of-rotation (EOR) evaluation tool to assess medical knowledge, oral presentation, and written communication skills administered to the residents at the end of each core subspecialty rotation. The benefit of continual assessment is obvious from a program perspective; the purpose of this article is to evaluate the residents' perception of the process. MATERIALS AND METHODS: All residents (n = 31, 28 postgraduate years two through five and 3 postgraduate year one) participate in the mandatory EOR evaluation as a required component of the residency program. After receiving Institutional Review Board approval, informed consent was obtained from the residents wishing to participate in quarterly 16-question online surveys assessing their experience. Each survey consists of 15 questions with Likert scale responses (1 through 5 from strongly disagree to strongly agree) and one free text answer. Data are collected quarterly, starting in September 2011. RESULTS: Overall, the residents' response has been positive. The new evaluation method is felt to be more meaningful than (average 3.9, standard deviation 0.9) and is favored by the residents over the traditional competency-based evaluation (average 4.0, standard deviation 1.0). However, residents retain neutral attitudes regarding preparation for boards or changes in study habits (average score 3.6, standard deviation 0.9 and 3.6, and standard deviation 1.1, respectively). CONCLUSION: Residents rate the EOR evaluation experience positively, although they do not report changes in study habits or increased preparedness for the new certifying examination.

Presurgical localization of parathyroid adenomas with magnetic resonance imaging at 3.0 T: an adjunct method to supplement traditional imaging.

PURPOSE: To investigate the use of a chemical shift-based water-fat separation magnetic resonance imaging (MRI) method, and time-resolved contrast-enhanced MRI at 3 T for improved presurgical localization of parathyroid adenomas. METHODS: Twenty-five patients with primary hyperparathyroidism were prospectively enrolled. Patients underwent MRI, which was reviewed by two experienced neuroradiologists who were blinded to Tc-99m sestamibi imaging and operative results. RESULTS: Overall, MRI detected 16 adenomas in 25 patients (sensitivity 64%, positive predictive value 67%), while sestamibi detected 18 of 25 adenomas (sensitivity 72%, positive predictive value 90%). Importantly, MRI was able to detect adenomas in four (57%) of the seven patients whose disease was missed by sestamibi analysis. MRI demonstrated excellent image quality and fat suppression by using a chemical shift-based water-fat separation technique. The time-resolved MRI was considered to be less helpful, although in some cases it was indispensable. CONCLUSIONS: MRI is an excellent adjunct for preoperative parathyroid localization. The advent of improved fat suppression techniques in the neck, including chemical shift-based water-fat separation, is critical to its utility. Although time-resolved MRI was not always helpful, it was crucial in certain cases. It may prove to be more useful with the development of faster scanning techniques.

Thyroid abscess as a complication of bacterial throat infection.

Thyroid abscesses are rare complications of neck infections. We report the case of a teenager who developed increasing neck pain and swelling following treatment for a Streptococcus throat infection. Imaging demonstrated a complex fluid collection in the left thyroid lobe. Ultrasound guided aspiration was performed for diagnostic purposes, yielding purulent fluid that grew multiple bacterial species. Following initial antibiotic treatment, the patient underwent definitive surgical management. Underlying risk factors and imaging techniques will be reviewed.

Improved time-of-flight magnetic resonance angiography with IDEAL water-fat separation.

PURPOSE: To implement IDEAL (iterative decomposition of water and fat using echo asymmetry and least squares estimation) water-fat separation with 3D time-of-flight (TOF) magnetic resonance angiography (MRA) of intracranial vessels for improved background suppression by providing uniform and robust separation of fat signal that appears bright on conventional TOF-MRA. MATERIALS AND METHODS: IDEAL TOF-MRA and conventional TOF-MRA were performed in volunteers and patients undergoing routine brain MRI/MRA on a 3T magnet. Images were reviewed by two radiologists and graded based on vessel visibility and image quality. RESULTS: IDEAL TOF-MRA demonstrated statistically significant improvement in vessel visibility when compared to conventional TOF-MRA in both volunteer and clinical patients using an image quality grading system. Overall image quality was 3.87 (out of 4) for IDEAL versus 3.55 for conventional TOF imaging (P = 0.02). Visualization of the ophthalmic artery was 3.53 for IDEAL versus 1.97 for conventional TOF imaging (P < 0.00005) and visualization of the superficial temporal artery was 3.92 for IDEAL imaging versus 1.97 for conventional TOF imaging (P < 0.00005). CONCLUSION: By providing uniform suppression of fat, IDEAL TOF-MRA provides improved background suppression with improved image quality when compared to conventional TOF-MRA methods.

Noninvasive dynamic magnetic resonance angiography with Time-Resolved Imaging of Contrast KineticS (TRICKS) in the evaluation of orbital vascular lesions.

OBJECTIVE: To evaluate the clinical utility of time-resolved contrast-enhanced magnetic resonance angiography (MRA) in the evaluation of vascular orbital tumors. METHODS: Retrospective medical record review of patients with vascular orbital lesions imaged with Time-Resolved Imaging of Contrast KineticS (TRICKS; GE Healthcare [Chalfont St Giles, England]) MRA, a noninvasive dynamic imaging modality. RESULTS: Five patients with orbital vascular tumors were evaluated using TRICKS MRA. These included 1 patient with a cavernous hemangioma, 2 patients with orbital varices, 1 patient with an orbitocutaneous arteriovenous malformation, and 1 patient who had a solitary fibrous tumor with features of a hemangiopericytoma. In 2 patients, diagnoses were altered as a result of TRICKS MRA. In addition, a young patient with a large orbitocutaneous arteriovenous malformation involving the ophthalmic artery was followed perioperatively and noninvasively using TRICKS MRA, which produced exquisite images and added substantial value in the care of these patients. CONCLUSION: Dynamic MRA in the form of TRICKS is a newly available imaging modality with great potential for improving the evaluation and management of patients with complex orbital tumors.

Variability of clinical CT perfusion measurements in patients with carotid stenosis.

INTRODUCTION: CT perfusion imaging (pCT) may be used to detect and monitor hemodynamic abnormalities due to cerebrovascular disease. The magnitude of variability in clinical measurements has been insufficiently evaluated. The purpose of this study was to measure the long-term variability of clinical pCT measurements in patients with cerebrovascular disease. METHODS: pCT parameters were calculated for the cerebral hemisphere contralateral to a carotid stenosis before and after stent treatment of stenosis in 33 consecutive patients. Mean transit time (MTT), cerebral blood flow (CBF), and cerebral blood volume (CBV) calculated from pCT data from both a small and large region of interest (ROI) using both manual and automated methods were compared before and after stent treatment. Differences between the first and second measurement were tested for statistical significance with at-test. Variability was calculated as the standard deviation of the differences divided by the mean of the pre- and post-stent treatment values. To adjust for proportional bias, the Bland-Altman analysis was applied. RESULTS: The differences between the two measurements of MTT, CBF, and CBV averaged 2.5 to 7.7% when a manual method was used and was higher with automatic methods (p > 0.07). The variability of the values was 18% for MTT, 19% for CBV, and 25% for CBF with the large ROI and the manual method of calculation. The magnitude was larger when the small ROI and automatic methods were employed. CONCLUSION: Longitudinal measurements of MTT, CBV, or CBF by pCT may vary by 20-25%. To detect changes in treatment-related changes in perfusion, pCT studies must be designed to achieve statistical significance based on this variability.