Faculty Bibliography

Dynamic contrast-enhanced (DCE) MR imaging uses rapid sequential MR image acquisition before, during, and after intravenous contrast administration to elucidate information on the microvascular biologic function of tissues. The derived pharmacokinetic parameters provide useful information on tissue perfusion and permeability that may help to evaluate entities that otherwise appear similar by conventional imaging. When specifically applied to the evaluation of head and neck cancer, DCE-MR imaging may provide valuable information to help predict treatment response, discriminate between posttreatment changes and residual tumor, and discriminate between various head and neck neoplasms.

The major salivary glands can be affected by a variety of acute or chronic, systemic, and neoplastic conditions. Several modalities can be used for salivary gland imaging, each with its own advantages and limitations. The article reviews the optimal imaging modality for different clinical scenarios, the typical imaging appearance of commonly encountered pathologies, and seeks to provide a framework for generating an appropriate differential diagnosis. Additionally, with regard to neoplastic conditions, the goals of the review are to highlight features suggestive of benign or low-grade lesions versus high-grade malignancy, while recognizing the limitations of imaging in making specific histologic diagnoses.

Coloboma of the eye, Heart defects, Atresia of the choanae, Retardation of growth and/or development, Genital and/or urinary abnormalities, and Ear abnormalities and deafness (CHARGE) syndrome is a disorder with multiple congenital anomalies seen on imaging. A retrospective review of 10 patients with CHARGE syndrome who underwent MR imaging of the brain as part of a preoperative evaluation for cochlear implantation was conducted. Structural abnormalities of the entire MR imaging of the head were evaluated, including the auditory system, olfactory system, face, skull base, and central nervous system. The most frequent MR imaging findings included dysplasias of the semicircular canals and hypoplasia of the frontal lobe olfactory sulci. Less frequent findings included cleft lip/palate and coloboma. Our study uncovered new findings of a J-shaped sella, dorsal angulation of the clivus, and absent/atrophic parotid glands, not previously described in patients with CHARGE. Our results emphasize the utility of MR imaging in the diagnosis and management of patients with CHARGE syndrome.

BACKGROUND AND PURPOSE: Clinical history is known to influence interpretation of a wide range of radiologic examinations. We sought to evaluate the influence of the clinical history on MRI interpretation of optic neuropathy. MATERIALS AND METHODS: 107 consecutive orbital MRI scans were retrospectively reviewed by three neuroradiologists. The readers independently evaluated the coronal STIR sequence for optic nerve hyperintensity and/or atrophy (yes/no) and the coronal post-contrast T1WI for optic nerve enhancement (yes/no). Readers initially evaluated the cases blinded to the clinical history. Following a two week washout period, readers again evaluated the cases with the clinical history provided. Inter-reader and reader-clinical radiologist agreement was assessed using Cohen's simple kappa coefficient. RESULTS: Intra-reader agreement, without and with provision of clinical history, was 0.564-0.716 on STIR and 0.270-0.495 on post-contrast T1WI. Inter-reader agreement was overall fair-moderate. On post-contrast T1WI, inter-reader agreement was significantly higher when the clinical history was provided (p = 0.001). Reader-clinical radiologist agreement improved with provision of the clinical history to the readers on both the STIR and post-contrast T1WI sequences. CONCLUSIONS: In the MRI assessment of optic neuropathy, only modest levels of inter-reader agreement were achieved, even after provision of clinical history. Provision of clinical history improved inter-reader agreement, especially when assessing for optic nerve enhancement. These findings confirm the subjective nature of orbital MRI interpretation in cases of optic neuropathy, and point to the importance of an accurate clinical history. Of note, the accuracy of orbital MRI in the context of optic neuropathy was not assessed, and would require further investigation.

OBJECTIVE: This article explores recent developments in PET and MRI, separately or combined, for assessing metastatic lymph nodes in patients with head and neck cancer. CONCLUSION: The synergistic role of PET and MRI for imaging metastatic lymph nodes has not been fully explored. To facilitate the understanding of the areas that need further investigation, we discuss potential mechanisms and evidence reported so far, as well as future directions and challenges for continued development and clinical research.

Contraindications to transesophageal echocardiography (TEE) include various esophageal pathologies, but compression of the esophagus by vertebral osteophytes is not listed in the current American Society of Echocardiography guidelines. We report a case of diffuse idiopathic skeletal hyperostosis (DISH) in an 81-year-old man who had incidentally been found to have extrinsic esophageal compression by cervical osteophytes prior to a proposed TEE. The incidence of esophageal perforation in patients with DISH and vertebral osteophytes is not well documented. We believe these patients are at increased risk of esophageal perforation during TEE, and thus, TEE may be relatively contraindicated in patients with DISH.

The purpose of the present review is to discuss and display orbital lesions that demonstrate hypo-intense signal on T2-weighted images (T2WI). The physical basis for hypo-intense signal on T2WI produced by various substances is discussed. Orbital lesions that are hypo-intense on T2WI are subsequently reviewed, including a discussion on their composition as well as relevant clinical and imaging clues that may aid in their diagnosis.

BACKGROUND: Orbital decompression is frequently performed in the management of patients with sight-threatening and disfiguring Graves' ophthalmopathy. The quantitative measurements of the change in orbital volume after orbital decompression procedures are not definitively known. Furthermore, the quantitative effect of septal deviation on volume change has not been previously analyzed. OBJECTIVES: To provide quantitative measurement of orbital volume change after medial and inferior endoscopic decompression and describe a straightforward method of measuring this change using open-source technologies. A secondary objective was to assess the effect of septal deviation on orbital volume change. METHODS: A retrospective review was performed on all patients undergoing medial and inferior endoscopic orbital decompression for Graves' ophthalmopathy at a tertiary care academic medical center. Pre-operative and post-operative orbital volumes were calculated from computed tomography (CT) data using a semi-automated segmenting technique and Osirix, an open-source DICOM reader. Data were collected for pre-operative and post-operative orbital volumes, degree of septal deviation, time to follow-up scan, and individual patient Hertel scores. RESULTS: Nine patients (12 orbits) were imaged before and after decompression. Mean pre-operative orbital volume was 26.99cm(3) (SD=2.86cm(3)). Mean post-operative volume was 33.07cm(3) (SD=3.96cm(3)). The mean change in volume was 6.08cm(3) (SD=2.31cm(3)). The mean change in Hertel score was 4.83 (SD=0.75). Regression analysis of change in volume versus follow-up time to imaging indicates that follow-up time to imaging has little effect on change in volume (R=-0.2), and overall mean maximal septal deviation toward the operative side was -0.5mm. Negative values were attributed to deviation away form the operative site. A significant correlation was demonstrated between change in orbital volume and septal deviation distance site (R=0.66), as well as between change in orbital volume and septal deviation angle (R=0.67). Greater volume changes were associated with greater degree of septal deviation away from the surgical site, whereas smaller volume changes were associated with greater degree of septal deviation toward the surgical site. CONCLUSION: A straightforward, semi-automated segmenting technique for measuring change in volume following endoscopic orbital decompression is described. This method proved useful in determining that a mean increase of approximately 6cm in volume was achieved in this group of patients undergoing medial and inferior orbital decompression. Septal deviation appears to have an effect on the surgical outcome and should be considered during operative planning.

OBJECTIVE: Sequential computed tomography (CT) technique remains the most common protocol for CT evaluation of the head despite nearly universal adoption of continuous technique for all other body parts. This may be attributable to the belief by radiologists that this technique is superior to helical scanning uniquely for this indication. This study attempts to clarify the issue. METHODS: A phantom evaluation and a prospective randomized clinical image quality trial were performed comparing sequential and helical technique using the most current generation 128-row detector CT scanner. RESULTS: Phantom evaluation demonstrated equivalence between the 2 techniques for low-contrast resolution and line pair spatial discrimination. Continuous scanning provided the highest contrast-to-noise ratio. There was no significant difference between the 2 techniques regarding image quality except for cortical visualization at the cerebral hemispheres, which was subtly but significantly superior for sequential technique. CONCLUSIONS: Head CT image quality for sequential and continuous techniques are virtually equivalent.

Fungal sinusitis is characterized into invasive and noninvasive forms. The invasive variety is further classified into acute, chronic and granulomatous forms; and the noninvasive variety into fungus ball and allergic fungal sinusitis. Each of these different forms has a unique radiologic appearance. The clinicopathologic and corresponding radiologic spectrum and differences in treatment strategies of fungal sinusitis make it an important diagnosis for clinicians and radiologists to always consider. This is particularly true of invasive fungal sinusitis, which typically affects immuno compromised patients and is associated with significant morbidity and mortality. Early diagnosis allows initiation of appropriate treatment strategies resulting in favorable outcome.