Labyrinthine Fluid Signal Intensity on T2-Weighted MR Imaging in Patients With Vestibular Schwannomas Undergoing Proton Radiotherapy: A Longitudinal Assessment.

OBJECTIVE: In vestibular schwannoma patients, a loss of signal intensity (SI) on T2-weighted magnetic resonance imaging (MRI) has been reported within the ipsilateral labyrinth. The purpose of this study was to quantitatively evaluate the occurrence and course of this intensity loss in relation to proton radiotherapy and its possible association with hearing loss. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral center. PATIENTS: Patients who received proton therapy for a vestibular schwannoma and underwent at least two high-resolution T2-weighted cisternographic sequence (constructive interference in steady state/fast imaging employing steady-state acquisition/DRIVE) MRIs and audiometry assessments. MAIN OUTCOME MEASURES: Relative T2 SIs from the vestibules and basal/apical cochlear turns of the labyrinth, bilaterally. RESULTS: Ninety-five MRI scans from 34 patients were included. The apical turn of the ipsilateral cochlea showed a lower mean cochlear SI than on the contralateral side (±3.5 versus 5.0). The mean relative cochlear SI did not significantly change after proton radiotherapy. The ipsilateral vestibule showed a higher SI than the cochlea. The relative mean cochlear SI was not directly correlated to (the degree of) hearing loss before or after proton radiotherapy, nor did it predict future hearing loss. CONCLUSION: The relative mean cochlear SI on cisternographic T2-MRI in vestibular schwannoma patients is diminished on the treated side, when compared with the ipsilateral vestibule and the contralateral cochlea/vestibule. The SI of the ipsilateral cochlea does not further decrease after proton radiotherapy and seems to be related to the tumor rather than the therapy. The diminished cochlear SI does not correlate with subsequent loss of hearing.

CT-based assessment of laryngeal fracture patterns and associated soft tissue abnormality.

OBJECTIVE: Acute traumatic injuries to the larynx, including fractures of the hyoid bone, cricoid, and thyroid cartilage, are uncommon injuries. The purpose of this study was to assess fracture and soft tissue patterns associated with laryngeal trauma. METHODS: This was a retrospective review of patients with laryngeal fractures who presented to two level I trauma centers and underwent CT imaging. Imaging findings, including fractures of the cartilaginous structures of the larynx and hyoid bone, and soft tissue abnormalities including focal hematoma, edema with non-focal hemorrhage, and additional penetrating injuries were recorded. Frequencies of fracture patterns were recorded. RESULTS: Thyroid cartilage fractures were most frequently observed occurring in 45/55 patients, followed by cricoid fractures in 13/55 patients. Hyoid fractures were encountered in 8/55 patients. Multi-site fractures were observed in 12/55 patients with thyroid-cricoid fractures occurring in 8/12 patients, followed by thyroid-hyoid fractures in 2/12 patients. Most multi-site fractures occurred in association with focal supraglottic hematomas (10/12), supraglottic edema and non-focal hemorrhage (11/12), and focal subglottic hematoma (5/12). All 13 cricoid fractures occurred with either focal supraglottic hematoma (7), focal subglottic hematoma (4), or edema with non-focal hemorrhage (13). CONCLUSIONS: Thyroid cartilage fractures were the most frequently encountered fracture, followed by cricoid cartilage fractures. Cricoid fractures always occurred with soft tissue abnormalities. Recognition of fracture patterns in the setting of laryngeal trauma and associated patterns of soft tissue injury is important for practicing radiologists for early diagnosis of these conditions and reduction of associated morbidity. KEY POINTS: • Acute fractures to the larynx may be isolated fractures or occur as multi-focal fractures. • Thyroid cartilage fractures are the most frequent fractures followed by cricoid cartilage fractures. • Cricoid cartilage fractures always occurred in association with soft tissue abnormalities.

Global and Regional Brain Assessment with Quantitative MR Imaging in Patients with Prior Exposure to Linear Gadolinium-based Contrast Agents.

Purpose To assess the association of global and regional brain relaxation times in patients with prior exposure to linear gadolinium-based contrast agents (GBCAs). Materials and Methods The institutional review board approved this cross-sectional study. Thirty-five patients (nine who had received GBCA gadopentetate dimeglumine injections previously [one to eight times] and 26 patients who did not) who underwent brain magnetic resonance (MR) imaging with a mixed fast spin-echo pulse sequence were assessed. The whole brain was segmented according to white and gray matter by using a dual-clustering algorithm. In addition, regions of interest were measured in the globus pallidus, dentate nucleus, thalamus, and pons. The Mann-Whitney U test was used to assess the difference between groups. Multiple regression analysis was performed to assess the association of T1 and T2 with prior GBCA exposure. Results T1 values of gray matter were significantly shorter for patients with than for patients without prior GBCA exposure (P = .022). T1 of the gray matter of the whole brain (P < .001), globus pallidus (P = .002), dentate nucleus (P = .046), and thalamus (P = .026) and T2 of the whole brain (P = .004), dentate nucleus (P = .023), and thalamus (P = .002) showed a significant correlation with the accumulated dose of previous GBCA administration. There was no significant correlation between T1 and the accumulated dose of previous GBCA injections in the white matter (P = .187). Conclusion Global and regional quantitative assessments of T1 and T2 demonstrated an association with prior GBCA exposure, especially for gray matter structures. The results of this study confirm previous research findings that there is gadolinium deposition in wider distribution throughout the brain. © RSNA, 2016 Online supplemental material is available for this article.

Value of Imaging Part I: Perspectives for the Academic Radiologist.

With payers and policymakers increasingly scrutinizing the value of medical imaging, opportunities abound for radiologists and radiology health services researchers to meaningfully and rigorously demonstrate value. Part one of this two-part series on the value of imaging explores the concept of value in health care from the perspective of multiple stakeholders and discusses the opportunities and challenges for radiologists and health service researchers to demonstrate value. The current absence of meaningful national value metrics also presents an opportunity for radiologists to take the lead on the discussions of these metrics that may serve as the basis for future value-based payments. As both practitioners and investigators, radiologists should consider the perspectives of multiple stakeholders in all they do-interdisciplinary support and cooperation are essential to the success of value-focused imaging research and initiatives that improve patient outcomes. Radiology departments that align their cultures, infrastructures, and incentives to support these initiatives will greatly increase their chances of being successful in these endeavors.

The Value of Imaging Part II: Value beyond Image Interpretation.

Although image interpretation is an essential part of radiologists' value, there are other ways in which we contribute to patient care. Part II of the value of imaging series reviews current initiatives that demonstrate value beyond the image interpretation. Standardizing processes, reducing the radiation dose of our examinations, clarifying written reports, improving communications with patients and providers, and promoting appropriate imaging through decision support are all ways we can provide safer, more consistent, and higher quality care. As payers and policy makers push to drive value, research that demonstrates the value of these endeavors, or lack thereof, will become increasingly sought after and supported.

Assessment of relationships between implant insertion torque and cortical shape of the mandible using panoramic radiography: preliminary study.

PURPOSE: To assess the relationship between mandibular cortical bone status as determined with panoramic radiography and insertion torque (IT) in implant treatment. MATERIALS AND METHODS: Using panoramic radiographs, two dental radiologists assessed patients' mandibular cortical bone status and classified them into two groups-normal or abnormal (mildly, moderately, or severely resorbed)-based on morphologic features of the mandibular cortical bone margins. Kappa coefficients between the two dental radiologists were calculated to determine interexaminer variability. Included patients underwent implant placement and surgery, during which IT was measured. Patients were classified into three groups based on these measurements: 15 Ncm or lower, between 15 and 35 Ncm, and 35 Ncm or higher. Correlations between mandibular cortical bone morphology and measured IT were assessed and analyzed statistically. RESULTS: Ninety-six patients (34 men, 62 women; mean age 59.1 years) were included in this study; 73 (76.0%) displayed a normal cortex and 23 (24.0%) had an abnormal cortex. In patients with a normal cortex, 13 (8.6%) had IT measurements of 15 Ncm or lower, 42 (27.6%) between 15 and 35 Ncm, and 97 (63.8%) of 35 Ncm or higher. In patients with an abnormal cortex, 3 (4.9%) had IT of 15 Ncm or lower, 35 (57.4%) between 15 and 35 Ncm, and 23 (37.7%) of 35 Ncm or higher. IT values were significantly lower in patients with an abnormal cortex compared to those with a normal cortex. A significant correlation between morphology of the mandibular cortex and IT was observed. CONCLUSION: The mandibular cortical bone status assessed on panoramic radiographs correlates with implant IT, suggesting that panoramic radiographs may be used effectively to determine bone density before implant treatment.