Faculty Bibliography

OBJECTIVE:To determine if metal reduction magnetic resonance imaging sequences and changes in implant placement minimize artifact from cochlear implants and improve visualization of intracranial structures. STUDY DESIGN/METHODS:Cadaveric study. SETTING/METHODS:Tertiary referral center. PATIENTS/METHODS:Five cadaveric heads. INTERVENTIONS/METHODS:Specimens were implanted with Advanced Bionics HiRes Ultra3D devices at nasion-external auditory canal angles of 90, 120, and 160 degrees, and distances from the external auditory canal of 9 or 12 cm. Standard brain/internal auditory canal (IAC) sequences with metal artifact reducing technique were acquired in a 1.5T scanner. MAIN OUTCOME MEASURES/METHODS:The primary outcome was visibility of 14 intracranial structures graded on a 4-point scale (1, structures <50% visible; 2, >50% visible with some areas nonvisible from artifact; 3, artifact present but adequate for diagnosis; and 4, high quality). Scores were determined by experienced head and neck radiologists and compared with one-way analysis of variance. RESULTS:Imaging sequences included axial 5-mm whole-brain turbo spin echo (TSE) T2 with right to left and anterior to posterior encoding, fluid-attenuation inversion recovery high bandwidth, axial 5-mm whole-brain slice-encoding metal artifact correction (SEMAC), axial IAC constructive interference in steady state, and axial 3-mm T1 IAC with and without fat saturation. T1 IACs in axial and coronal planes were best for ipsilateral structures overall (mean [standard deviation {SD}], 3.8 [0.6] and 3.8 [0.5]). SEMAC (mean [SD], 3.5 [0.8]) was superior to TSE with anterior to posterior encoding (mean [SD], 3.5 [0.9) for ipsilateral cortex, cerebellopontine angle, and brainstem/cerebellum, and equivalent for the inner ear. Constructive interference in steady state and T1 with fat saturation were poor for all ipsilateral structures (mean, 2.8 [ p < 0.01]; mean, 3.1 [ p < 0.01]). The 120 degrees/12 cm position was overall best, although the 120 degrees/9 cm position still afforded visualization of ipsilateral structures; other angles and distances conferred slight advantages for specific structures of interest. CONCLUSIONS:SEMAC and T2 TSE with anterior to posterior encoding sequences provide artifact suppression while retaining excellent image quality. Different placement angles did not confer improvement in visualization, although placement distances provided slight advantages for some structures.

Sphenoorbital meningiomas are a challenge to access and reconstruct. Although there is much neurosurgical literature on resection of such tumors, there is little discussion on the best methods for the reconstruction of consequent defects, which are often extensive due to large areas of hyperostosis requiring resection. We performed a retrospective analysis of patients who underwent resection and reconstruction of a sphenoorbital meningioma by the senior authors (C.S. and D.A.S.) between 2010 and 2020. Surgical access in all cases included an orbitozygomatic osteotomy. The study cohort consisted of 23 patients (20 female, 3 male) with an average age of 50 (range: 37-72) years at the time of surgery. Most patients had progressive proptosis before the ablative operation. Orbital reconstruction was with a combined titanium-Medpor implant in 18 patients, split calvarial bone graft in 3 patients, and a Medpor implant in 2 patients. Calvarial reconstruction was performed with titanium mesh in 21 patients, split calvarial bone graft and titanium mesh in 1 patient, and craniotomy bone and titanium plate in 1 patient. Reoperation was required in 7 patients due to hypoglobus or enophthalmos (N=2), orbital implant malposition (N=1), abscess (N=1), pain (N=1), intracranial fat graft modification (N=1), and soft tissue deformities (N=2). Our experience demonstrates that sphenoorbital meningiomas can require broad areas of resection of the skull base and calvarium and necessitate comprehensive reconstruction of the anterior cranial fossa, orbital walls, and cranium. Collaboration between craniofacial surgeons and neurosurgeons can achieve optimal results.

Cranial neuropathy can result from pathology affecting the nerve fibers at any point and requires imaging of the entire course of the nerve from its nucleus to the end organ in order to identify a cause. MRI with and without intravenous contrast is often the modality of choice with CT playing a complementary role. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Many different benign and malignant processes affect the central skull base and petrous apices. Clinical evaluation and tissue sampling are difficult because of its deep location, leaving imaging assessment the primary means for lesion evaluation. Skull base lesions demonstrate a variety of confusing appearances on imaging, creating diagnostic dilemmas. It is important to be familiar with imaging appearances of common mimickers of malignant neoplasm in the skull base. This article familiarizes readers with imaging characteristics of various anatomic variants and benign pathologies that mimic malignant neoplasms, in hopes of increasing confidence of diagnosis, decreasing unnecessary procedures, and allaying patient fear.

This article presents guidelines for initial imaging utilization in patients presenting with sinonasal disease, including acute rhinosinusitis without and with suspected orbital and intracranial complications, chronic rhinosinusitis, suspected invasive fungal sinusitis, suspected sinonasal mass, and suspected cerebrospinal fluid leak. CT and MRI are the primary imaging modalities used to evaluate patients with sinonasal disease. Given its detailed depiction of bony anatomy, CT can accurately demonstrate the presence of sinonasal disease, bony erosions, and anatomic variants, and is essential for surgical planning. Given its superior soft tissue contrast, MRI can accurately identify clinically suspected intracranial and intraorbital complications, delineate soft tissue extension of tumor and distinguish mass from obstructed secretions.The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Maxillofacial trauma patients comprise a significant subset of patients presenting to emergency departments. Before evaluating for facial trauma, an emergency or trauma physician must perform a primary survey to ensure patient stabilization. Following this primary survey, this document discusses the following clinical scenarios for facial trauma: tenderness to palpation or contusion or edema over frontal bone (suspected frontal bone injury); pain with upper jaw manipulation or pain overlying zygoma or zygomatic deformity or facial elongation or malocclusion or infraorbital nerve paresthesia (suspected midface injury); visible nasal deformity or palpable nasal deformity or tenderness to palpation of the nose or epistaxis (suspected nasal bone injury); and trismus or malocclusion or gingival hemorrhage or mucosal hemorrhage or loose teeth or fractured teeth or displaced teeth (suspected mandibular injury). The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Pre- and postoperative imaging is increasingly used in plastic and reconstructive surgery for the evaluation of bony and soft tissue anatomy. Imaging plays an important role in preoperative planning. In the postoperative setting, imaging is used for the assessment of surgical positioning, bone healing and fusion, and for the assessment of early or delayed surgical complications. This article will focus on imaging performed for surgical reconstruction of the face, including orthognathic surgery, facial feminization procedures for gender dysphoria, and face transplantation.

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.

Hyperparathyroidism is defined as excessive parathyroid hormone production. The diagnosis is made through biochemical testing, in which imaging has no role. However, imaging is appropriate for preoperative parathyroid gland localization with the intent of surgical cure. Imaging is particularly useful in the setting of primary hyperparathyroidism whereby accurate localization of a single parathyroid adenoma can facilitate minimally invasive parathyroidectomy. Imaging can also be useful to localize ectopic or supernumerary parathyroid glands and detail anatomy, which may impact surgery. This document summarizes the literature and provides imaging recommendations for hyperparathyroidism including primary hyperparathyroidism, recurrent or persistent primary hyperparathyroidism after parathyroid surgery, secondary hyperparathyroidism, and tertiary hyperparathyroidism. Recommendations include ultrasound, CT neck without and with contrast, and nuclear medicine parathyroid scans. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Dizziness and vertigo are common symptoms in the primary care and emergency settings, resulting in a significant decrease in quality of life and a high cost burden to the US health care system. The etiology of these symptoms is difficult to elucidate owing to a wide range of diseases with overlapping manifestations. The broad differential diagnosis based on whether the disease process is central or peripheral is showcased. Each differential will be categorized into neoplastic, infectious or inflammatory, structural, traumatic, and iatrogenic causes. Computed tomography scans, MRI, and vascular imaging are frequently complimentary in providing diagnoses and guidance in management.