Faculty Bibliography

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.

BACKGROUND AND PURPOSE:Accurate differentiation of paragangliomas and schwannomas in the jugular foramen has important clinical implications because treatment strategies may vary but differentiation is not always straightforward with conventional imaging. Our aim was to evaluate the accuracy of both qualitative and quantitative metrics derived from dynamic contrast-enhanced MR imaging using golden-angle radial sparse parallel MR imaging to differentiate paragangliomas and schwannomas in the jugular foramen. MATERIALS AND METHODS:test. A univariate logistic model was created with a binary output, paraganglioma or schwannoma, using a wash-in rate as a variable. Additionally, lesions were clustered on the basis of the wash-in rate and washout rate using a 3-nearest neighbors method. RESULTS:< .001). All 30 lesions were classified correctly by using a 3-nearest neighbors method. CONCLUSIONS:Paragangliomas at the jugular foramen can be reliably differentiated from schwannomas using golden-angle radial sparse parallel MR imaging-dynamic contrast-enhanced imaging when imaging characteristics cannot suffice.

OBJECTIVE:To characterize a series of patients with MRI evidence of spontaneous vestibular schwannoma (VS) regression. STUDY DESIGN/METHODS:Retrospective case series. METHODS:Retrospective review between 2012 and 2020 from a single, tertiary-care center of all patients with an untreated, sporadic VS and spontaneous regression in volumetric tumor size over the course of observation. The main outcome measures included VS size and location, presenting symptoms, medication use, changes in pure-tone averages and word recognition scores. RESULTS:/yr). Five patients were classified as having major regression, defined by a relative decrease in volume of >40%, while eight patients had minor regression (<40% relative volume reduction). No significant differences in initial tumor size, rate of regression, or audiometric changes were observed between the major and minor regression cohorts. CONCLUSIONS:Patients with evidence of a spontaneously shrinking VS have a heterogeneous presentation. Due to the scarcity of this phenomenon, predicting which tumors will eventually undergo regression remains unclear. Employing volumetric measurements to compare serial MRI scans may improve the accuracy of detecting shrinking tumors. LEVEL OF EVIDENCE/METHODS:4 Laryngoscope, 2020.

ABSTRACT/UNASSIGNED:Magnetic resonance imaging (MRI) is the imaging modality of choice to evaluate the complex anatomy and pathology of the oral cavity. In this article, an overview of MRI findings of common benign lesions in the oral cavity including congenital, vascular, and inflammatory/infectious lesions will be reviewed. In addition, MRI findings of common benign and malignant oral cavity tumors will be presented.

In this study, we investigate the feasibility of using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI), diffusion weighted imaging (DWI), and dynamic positron emission tomography (PET) for detection of metastatic lymph nodes in head and neck squamous cell carcinoma (HNSCC) cases. Twenty HNSCC patients scheduled for lymph node dissection underwent DCE-MRI, dynamic PET, and DWI using a PET-MR scanner within one week prior to their planned surgery. During surgery, resected nodes were labeled to identify their nodal levels and sent for routine clinical pathology evaluation. Quantitative parameters of metastatic and normal nodes were calculated from DCE-MRI (v_e, v_p, PS, F_p, K^trans), DWI (ADC) and PET (K_i, K₁, k₂, k₃) to assess if an individual or a combination of parameters can classify normal and metastatic lymph nodes accurately. There were 38 normal and 11 metastatic nodes covered by all three imaging methods and confirmed by pathology. 34% of all normal nodes had volumes greater than or equal to the smallest metastatic node while 4 normal nodes had SUV > 4.5. Among the MRI parameters, the median v_p, F_p, PS, and K^trans values of the metastatic lymph nodes were significantly lower (p = <0.05) than those of normal nodes. v_e and ADC did not show any statistical significance. For the dynamic PET parameters, the metastatic nodes had significantly higher k₃ (p value = 8.8 × 10^-8) and K_i (p value = 5.3 × 10^-8) than normal nodes. K₁ and k₂ did not show any statistically significant difference. K_i had the best separation with accuracy = 0.96 (sensitivity = 1, specificity = 0.95) using a cutoff of K_i = 5.3 × 10^-3 mL/cm³/min, while k₃ and volume had accuracy of 0.94 (sensitivity = 0.82, specificity = 0.97) and 0.90 (sensitivity = 0.64, specificity = 0.97) respectively. 100% accuracy can be achieved using a multivariate logistic regression model of MRI parameters after thresholding the data with K_i < 5.3 × 10^-3 mL/cm³/min. The results of this preliminary study suggest that quantitative MRI may provide additional value in distinguishing metastatic nodes, particularly among small nodes, when used together with FDG-PET.

Oral cancer patients experience pain at the site of the primary cancer. Patients with metastatic oral cancers report greater pain. Lack of pain identifies patients at low risk of metastasis with sensitivity = 0.94 and negative predictive value = 0.89. In the same cohort, sensitivity and negative predictive value of depth of invasion, currently the best predictor, were 0.95 and 0.92, respectively. Cancer pain is attributed to cancer-derived mediators that sensitize neurons and is associated with increased neuronal density. We hypothesized that pain mediators would be overexpressed in metastatic cancers from patients reporting high pain. We identified 40 genes overexpressed in metastatic cancers from patients reporting high pain (n = 5) compared to N0 cancers (n = 10) and normal tissue (n = 5). The genes are enriched for functions in extracellular matrix organization and angiogenesis. They have oncogenic and neuronal functions and are reported in exosomes. Hierarchical clustering according to expression of neurotrophic and axon guidance genes also separated cancers according to pain and nodal status. Depletion of exosomes from cancer cell line supernatant reduced nociceptive behavior in a paw withdrawal assay, supporting a role for exosomes in cancer pain. The identified genes and exosomes are potential therapeutic targets for stopping cancer and attenuating pain.

The cavernous sinus is a complex structure susceptible to a wide variety of vascular, neoplastic and inflammatory pathologies. Vascular pathologies include ICA aneurysms, carotid-cavernous fistulas, cavernous sinus thrombosis, and cavernous hemangioma. Neoplasms that involve the cavernous sinus include pituitary adenoma, meningioma, schwannoma, lymphoma, perineural tumor spread, metastases, and direct tumor invasion. Infectious and inflammatory diseases include Tolosa-Hunt syndrome, sarcoidosis, granulomatosis with polyangiitis, IgG-4 related disease and invasive fungal infections. In this article, we review the clinical and imaging findings of a number of pathologies involving the cavernous sinus, focusing on key features that can narrow the differential diagnosis and, in some cases, support a particular diagnosis.