Characterizing mandibular growth using three-dimensional imaging techniques and anatomic landmarks.

OBJECTIVE: To provide quantitative data on the multi-planar growth of the mandible, this study derived accurate linear and angular mandible measurements using landmarks on three dimensional (3D) mandible models. This novel method was used to quantify 3D mandibular growth and characterize the emergence of sexual dimorphism. DESIGN: Cross-sectional and longitudinal imaging data were obtained from a retrospective computed tomography (CT) database for 51 typically developing individuals between the ages of one and nineteen years. The software Analyze was used to generate 104 3DCT mandible models. Eleven landmarks placed on the models defined six linear measurements (lateral condyle, gonion, and endomolare width, ramus and mental depth, and mandible length) and three angular measurements (gonion, gnathion, and lingual). A fourth degree polynomial fit quantified growth trends, its derivative quantified growth rates, and a composite growth model determined growth types (neural/cranial and somatic/skeletal). Sex differences were assessed in four age cohorts, each spanning five years, to determine the ontogenetic pattern producing sexual dimorphism of the adult mandible. RESULTS: Mandibular growth trends and growth rates were non-uniform. In general, structures in the horizontal plane displayed predominantly neural/cranial growth types, whereas structures in the vertical plane had somatic/skeletal growth types. Significant prepubertal sex differences in the inferior aspect of the mandible dissipated when growth in males began to outpace that of females at eight to ten years of age, but sexual dimorphism re-emerged during and after puberty. CONCLUSIONS: This 3D analysis of mandibular growth provides preliminary normative developmental data for clinical assessment and craniofacial growth studies.

Aspergillus Mycetoma Causing Epiphora and Ipsilateral Facial Pain.

Tearing is a frequently encountered chief complaint in an ophthalmologist's office. Certain associated atypical symptoms may warrant further workup. The authors present a case of a patient presenting with painful tearing which elicited further evaluation with CT imaging. This revealed a maxillary sinus fungus ball as the cause for the patient's tearing.

Development of PVDF Membrane Nanocomposites via Various Functionalization Approaches for Environmental Applications.

Membranes are finding wide applications in various fields spanning biological, water, and energy areas. Synthesis of membranes to provide tunable flux, metal sorption, and catalysis has been done through pore functionalization of microfiltration (MF) type membranes with responsive behavior. This methodology provides an opportunity to improve synthetic membrane performance via polymer fabrication and surface modification. By optimizing the polymer coagulation conditions in phase inversion fabrication, spongy polyvinylidene fluoride (PVDF) membranes with high porosity and large internal pore volume were created in lab and full scale. This robust membrane shows a promising mechanical strength as well as high capacity for loading of adsorptive and catalytic materials. By applying surface modification techniques, synthetic membranes with different functionality (carboxyl, amine, and nanoparticle-based) were obtained. These functionalities provide an opportunity to fine-tune the membrane surface properties such as charge and reactivity. The incorporation of stimuli-responsive acrylic polymers (polyacrylic acid or sodium polyacrylate) in membrane pores also results in tunable pore size and ion-exchange capacity. This provides the added benefits of adjustable membrane permeability and metal capture efficiency. The equilibrium and dynamic binding capacity of these functionalized spongy membranes were studied via calcium ion-exchange. Iron/palladium catalytic nanoparticles were immobilized in the polymer matrix in order to perform the challenging degradation of the environmental pollutant trichloroethylene (TCE).

The Many Faces of Granulomatosis With Polyangiitis: A Review of the Head and Neck Imaging Manifestations.

OBJECTIVE: Wegener granulomatosis has recently been renamed as granulomatosis with polyangiitis (GPA). In this review, we examine the clinical criteria and pathologic and pathophysiologic mechanisms of GPA, with an emphasis on findings encountered in the realm of head and neck imaging. Particular attention is paid to generating an appropriate differential diagnosis, because many of the imaging features of GPA overlap with those of other diseases, most notably lymphoma and sarcoidosis. Recent therapeutic advancements have underscored the importance of the radiologist in suggesting the diagnosis early, resulting in earlier treatment and decreased patient morbidity. This is particularly true for the head and neck manifestations of GPA; although they are less common, they often herald a refractory disease course that requires aggressive immunosuppressive therapy. Knowledge of common and uncommon imaging findings enables the radiologist to diagnose GPA early enough to start treatment promptly and reduce patient morbidity. CONCLUSION: Although there are no reliable pathognomonic imaging features for GPA, the present article attempts to identify patterns of disease that are suggestive of the disease. The diagnosis ultimately relies on a constellation of radiographic findings, laboratory values, and accurate clinical history.

Pterygoid Plate Fractures: Not Limited to Le Fort Fractures.

Pterygoid plate fractures are often described in the setting of Le Fort fractures. The goal of this study was to define other craniofacial fracture patterns causing injury to the pterygoid plates. A retrospective review of computed tomography (CT) scans obtained on craniofacial trauma patients over a 5-year period revealed 209 patients with pterygoid plate fractures. Pterygoid plate fractures in 78 patients (37.3%) were unrelated to Le Fort fractures. Common causes included sphenotemporal buttress fractures in 26 patients (33.3%), temporal bone fractures in 18 patients (23.1%), zygomaticomaxillary complex fractures in 17 patients (21.8%), and displaced mandible fractures in 14 patients (17.9%). These findings indicate that approximately one third of pterygoid plate fractures do not result from Le Fort pattern injuries and that the craniofacial surgeon should have a broad differential for causes of pterygoid plate fractures when reviewing trauma imaging.

Validation of Clinical Criteria for Obtaining Maxillofacial Computed Tomography in Patients With Trauma.

BACKGROUND: More than 180,000 patients present annually with facial trauma to emergency rooms in the United States. Maxillofacial computed tomography is the gold standard in identifying facial fractures. Providers must evaluate patients quickly; therefore, they use decision instruments to determine which patients need imaging. We previously developed a decision instrument that identified patients with trauma at low risk for facial fracture who could avoid imaging. The present study aims to perform an internal validation of that tool. METHODS: The decision instrument used 5 criteria: bony step-off or instability, periorbital swelling or contusion, Glasgow Coma Scale <14, malocclusion, and tooth absence. The presence of any 1 finding placed the patient at high risk for fracture. In the present study, a retrospective review was conducted on all of the patients with trauma evaluated at a Level I trauma center for >1 year. Inclusion criteria were maxillofacial physical examination, head and maxillofacial computed tomography at presentation. Physical examination findings were collected and imaging reviewed to determine whether the decision tool could accurately detect the presence of a facial fracture in a different patient population from which it was derived. RESULTS: One hundred seventy-nine patients met enrollment criteria. Facial fractures occurred in 81% of patients (n = 145). The decision instrument was 97.4% sensitive (95% confidence interval, 93.8-99.3) for the presence of facial fracture. The negative predictive value was 81.3% (95% confidence interval, 55.0-95.0). Application of the instrument resulted in a missed injury rate of 2.6% (n = 3). All of the missed fractures were nondisplaced and managed nonoperatively. CONCLUSIONS: The proposed decision tool identifies patients with trauma at low risk for facial fracture who can avoid maxillofacial imaging. Validation in a prospective study is warranted.

Hyoid Bone Development: An Assessment Of Optimal CT Scanner Parameters and Three-Dimensional Volume Rendering Techniques.

The hyoid bone anchors and supports the vocal tract. Its complex shape is best studied in three dimensions, but it is difficult to capture on computed tomography (CT) images and three-dimensional volume renderings. The goal of this study was to determine the optimal CT scanning and rendering parameters to accurately measure the growth and developmental anatomy of the hyoid and to determine whether it is feasible and necessary to use these parameters in the measurement of hyoids from in vivo CT scans. Direct linear and volumetric measurements of skeletonized hyoid bone specimens were compared with corresponding CT images to determine the most accurate scanning parameters and three-dimensional rendering techniques. A pilot study was undertaken using in vivo scans from a retrospective CT database to determine feasibility of quantifying hyoid growth. Scanning parameters and rendering technique affected accuracy of measurements. Most linear CT measurements were within 10% of direct measurements; however, volume was overestimated when CT scans were acquired with a slice thickness greater than 1.25 mm. Slice-by-slice thresholding of hyoid images decreased volume overestimation. The pilot study revealed that the linear measurements tested correlate with age. A fine-tuned rendering approach applied to small slice thickness CT scans produces the most accurate measurements of hyoid bones. However, linear measurements can be accurately assessed from in vivo CT scans at a larger slice thickness. Such findings imply that investigation into the growth and development of the hyoid bone, and the vocal tract as a whole, can now be performed using these techniques.

Nasolacrimal System Fractures: A Description of Radiologic Findings and Associated Outcomes.

BACKGROUND: Fractures of the bony nasolacrimal system (NLS), including the lacrimal sac fossa and nasolacrimal canal, have not been comprehensively described in patients with facial trauma. Characterization of these injuries may help facial trauma surgeons better predict which patients will develop lacrimal outflow obstruction symptoms including epiphora and dacryocystitis and who may eventually need lacrimal surgery. METHODS: CT images for all patients seen at the University of Wisconsin Hospital and Clinics for craniofacial trauma were reviewed from January 2001 to December 2005. Patients were included if they had a NLS fracture and at least 1 year of follow-up. Fracture patterns were described and correlated with clinical outcomes documented in the medical record. Outcomes, including the development of epiphora or dacryocystitis and the need for lacrimal surgery, were analyzed using Fisher exact test. RESULTS: We identified 104 patients with NLS fractures among 1980 patients with craniofacial trauma who had at least 1 year of follow-up. Eleven patients (10.6%) developed epiphora or dacryocystitis, and 2 patients (1.9%) required dacryocystorhinostomy (DCR). Ten radiographic injury patterns were characterized. Avulsion of the lacrimal crest, bone fragment in the lacrimal sac fossa or duct, duct compression greater than 50%, and nasomaxillary buttress displacement were significantly associated with the development of epiphora or dacryocystitis (P < 0.05). Nasomaxillary buttress displacement was significantly associated with the eventual need for DCR (P = 0.03). CONCLUSIONS: Patients with radiographic evidence of NLS fracture have an approximately 10% risk of developing epiphora or dacryocystitis. We describe 5 NLS fracture findings that are significantly associated with the development of lacrimal outflow obstruction. The presence of nasomaxillary buttress fracture and displacement suggests a significantly higher risk of eventually needing lacrimal surgery.

A novel classification of frontal bone fractures: The prognostic significance of vertical fracture trajectory and skull base extension.

PURPOSE: The broad spectrum of frontal bone fractures, including those with orbital and skull base extension, is poorly understood. We propose a novel classification scheme for frontal bone fractures. METHODS: Maxillofacial CT scans of trauma patients were reviewed over a five year period, and frontal bone fractures were classified: Type 1: Frontal sinus fracture without vertical extension. Type 2: Vertical fracture through the orbit without frontal sinus involvement. Type 3: Vertical fracture through the frontal sinus without orbit involvement. Type 4: Vertical fracture through the frontal sinus and ipsilateral orbit. Type 5: Vertical fracture through the frontal sinus and contralateral or bilateral orbits. We also identified the depth of skull base extension, and performed a chart review to identify associated complications. RESULTS: 149 frontal bone fractures, including 51 non-vertical frontal sinus (Type 1, 34.2%) and 98 vertical (Types 2-5, 65.8%) fractures were identified. Vertical fractures penetrated the middle or posterior cranial fossa significantly more often than non-vertical fractures (62.2 v. 15.7%, p = 0.0001) and had a significantly higher mortality rate (18.4 v. 0%, p < 0.05). Vertical fractures with frontal sinus and orbital extension, and fractures that penetrated the middle or posterior cranial fossa had the strongest association with intracranial injuries, optic neuropathy, disability, and death (p < 0.05). CONCLUSIONS: Vertical frontal bone fractures carry a worse prognosis than frontal bone fractures without a vertical pattern. In addition, vertical fractures with extension into the frontal sinus and orbit, or with extension into the middle or posterior cranial fossa have the highest complication rate and mortality.

Phase 1 trial of bevacizumab with concurrent chemoradiation therapy for squamous cell carcinoma of the head and neck with exploratory functional imaging of tumor hypoxia, proliferation, and perfusion.

PURPOSE: A phase 1 trial was completed to examine the safety and feasibility of combining bevacizumab with radiation and cisplatin in patients with locoregionally advanced squamous cell carcinoma of the head and neck (HNSCC) treated with curative intent. Additionally, we assessed the capacity of bevacizumab to induce an early tumor response as measured by a series of biological imaging studies. METHODS AND MATERIALS: All patients received a single induction dose of bevacizumab (15 mg/kg) delivered 3 weeks (±3 days) before the initiation of chemoradiation therapy. After the initial dose of bevacizumab, comprehensive head and neck chemoradiation therapy was delivered with curative intent to 70 Gy in 33 fractions with concurrent weekly cisplatin at 30 mg/m(2) and bevacizumab every 3 weeks (weeks 1, 4, 7) with dose escalation from 5 to 10 to 15 mg/kg. All patients underwent experimental imaging with [(18)F]fluorothymidine positron emission tomography (FLT-PET) (proliferation), [(61)Cu]Cu-diacetyl-bis(N4-methylthiosemicarbazone) PET (Cu-ATSM-PET) (hypoxia), and dynamic contrast-enhanced computed tomography (DCE-CT) (perfusion) at 3 time points: before bevacizumab monotherapy, after bevacizumab monotherapy, and during the combined therapy course. RESULTS: Ten patients were enrolled. All had stage IV HNSCC, all achieved a complete response to treatment, and 9 of 10 remain alive, with a mean survival time of 61.3 months. All patients experienced grade 3 toxicity, but no dose-limiting toxicities or significant bleeding episodes were observed. Significant reductions were noted in tumor proliferation (FLT-PET), tumor hypoxia (Cu-ATSM-PET), and DCE-CT contrast enhancement after bevacizumab monotherapy, with further decreases in FLT-PET and Cu-ATSM-PET during the combined therapy course. CONCLUSIONS: The incorporation of bevacizumab into comprehensive chemoradiation therapy regimens for patients with HNSCC appears safe and feasible. Experimental imaging demonstrates measureable changes in tumor proliferation, hypoxia, and perfusion after bevacizumab monotherapy and during chemoradiation therapy. These findings suggest opportunities to preview the clinical outcomes for individual patients and thereby design personalized therapy approaches in future trials.

Imaging of head and neck emergencies.

The anatomy of the head and neck contains very few structures that could be considered expendable and, consequently, is exceptionally intolerant to infection, inflammation, and injury. Acute pathologic processes in this body region, therefore, tend to result in significant suffering, functional impairment, or life endangerment if the diagnosis is missed or treatment is delayed. Many emergent processes within the cervical region also need to be considered for their possible impact on structures within the head and chest, into which there are many routes for potential communication.

Imaging of temporal bone trauma.

Temporal bone trauma is commonly seen in patients with craniofacial injury and can be detected using multidetector computed tomography. A thorough understanding of the different types of temporal bone fracture patterns is needed to accurately describe the trajectory of injury as well as anticipated complications. Fractures should be described based on direction, segment of temporal bone involved, as well as involvement of the otic capsule. More importantly, the radiologist plays an integral role in identifying complications of temporal bone injury, which often have significant clinical implications.

Cerebrovascular trauma.

Significant progress has been made recently in the recognition, screening, diagnosis, and treatment of blunt cerebrovascular vascular injury (BCVI). Although controversy still exists as to optimal screening algorithms and best diagnostic modality, the vital and growing role of noninvasive imaging in identifying patients at high risk for BCVI and in characterizing the injury itself has been clearly established. There has been promising early work in stratifying BCVI patients into risk categories by initially evaluating them with high-resolution head, maxillofacial, and cervical computed tomographic examinations with the ultimate goal of maximizing diagnostic yield and enabling prompt initiation of therapy.

Radiographic features of superior semicircular canal dehiscence in the setting of chronic ear disease.

OBJECTIVE: To determine if radiologic chronic otitis media (COM), both with and without cholesteatoma, is associated with superior semicircular canal dehiscence (SSCD). STUDY DESIGN: Retrospective review of consecutive high-resolution computed tomography (HRCT) scans of the temporal bone. SETTING: Tertiary care medical center. PATIENTS: Two hundred consecutive patients undergoing HRCT of the temporal bone beginning January 1, 2012. INTERVENTION: Imaging was evaluated by 3 reviewers (2 neuroradiologists and 1 neurotologist). All scans were assessed for the presence of SSCD, cholesteatoma, chronic otomastoiditis, tegmen dehiscence, and for abnormalities of the cochlea, vestibule, facial nerve, and temporal bone vasculature. MAIN OUTCOME MEASURE: Ears with COM associated with chronic otomastoiditis or cholesteatoma were compared with those without COM with respect to the presence of SSCD or other temporal bone abnormalities. Statistical analysis was performed to assess for differences between the groups studied. RESULTS: One-hundred ninety-four patients (388 ears) were included. Cholesteatoma was identified in 48 ears (12.4%) and chronic otomastoiditis in 62 ears (16%). Ten ears with cholesteatoma had ipsilateral SSCD, and 8 ears with chronic otomastoiditis had ipsilateral SSCD. In 340 ears without either cholesteatoma or chronic otomastoiditis, SSCD was found in 18 (5.3%). SSCD was found to occur significantly more often in patients with ipsilateral radiologic cholesteatoma. No cases of SSCD were associated with cochlear, facial nerve, or vascular abnormalities. CONCLUSION: Our findings suggest that COM with cholesteatoma is associated with the presence of SSCD, although the nature of this association is unclear.

The effect of computed tomographic scanner parameters and 3-dimensional volume rendering techniques on the accuracy of linear, angular, and volumetric measurements of the mandible.

OBJECTIVES: This study investigates the effect of scanning parameters on the accuracy of measurements from three-dimensional (3D), multi-detector computed tomography (MDCT) mandible renderings. A broader range of acceptable parameters can increase the availability of computed tomographic (CT) studies for retrospective analysis. STUDY DESIGN: Three human mandibles and a phantom object were scanned using 18 combinations of slice thickness, field of view (FOV), and reconstruction algorithm and 3 different threshold-based segmentations. Measurements of 3D computed tomography (3DCT) models and specimens were compared. RESULTS: Linear and angular measurements were accurate, irrespective of scanner parameters or rendering technique. Volume measurements were accurate with a slice thickness of 1.25 mm, but not 2.5 mm. Surface area measurements were consistently inflated. CONCLUSIONS: Linear, angular, and volumetric measurements of mandible 3D MDCT models can be confidently obtained from a range of parameters and rendering techniques. Slice thickness is the primary factor affecting volume measurements. These findings should also apply to 3D rendering using cone-beam CT (CBCT).

When is fluid in the mastoid cells a worrisome finding?

Mastoiditis is a common clinical entity that is technically present in all cases of otitis media; only a minority of cases actually represents the otolaryngologic emergency of acute coalescent mastoiditis. When reviewing an image with a radiologic diagnosis of mastoiditis, looking for key signs such as destruction of bony septa and considering patient presentation can help distinguish mild mastoiditis from acute coalescent mastoiditis.

Orbital fibrous histiocytoma mimicking cavernous hemangioma on dynamic contrast-enhanced MRA imaging.

Orbital lesions include a broad spectrum of tumors, vascular abnormalities, and inflammatory conditions. High-resolution imaging has become an invaluable tool toward formulating an accurate diagnosis, and facilitates proper counseling regarding appropriate interventions. Imaging may guide whether partial excision to minimize damage to orbital structures, or en bloc removal to prevent potential recurrence, as seen in mesenchymal tumors, is indicated., Recently, dynamic contrast-enhanced magnetic resonance angiography (MRA) has demonstrated use in helping differentiate orbital vascular lesions. This imaging modality uses rapid MRI acquisition to provide noninvasive, dynamic flow information with high spatial resolution. However, even with modern imaging, reaching a diagnosis prior to histopathological analysis can be challenging. We present a case of orbital fibrous histiocytoma that appeared nearly identical to cavernous hemangioma on dynamic contrast-enhanced MRA.

Aggressive inflammatory and neoplastic processes of the paranasal sinuses.

Although uncommon, sinonasal malignancies and aggressive inflammatory processes are entities every radiologist will encounter during the evaluation of routine sinus imaging studies. A high index of suspicion is necessary for prompt diagnosis. It is important to consider aggressive inflammatory disease in all patients having routine sinus computed tomography because any delay in diagnosis can adversely affect the patients' care. Magnetic resonance (MR) will often provide a better assessment of the lesion extent, allowing for better surgical treatment. MR is crucial for the accurate assessment of neoplastic lesions. A proficient understanding of the complex anatomy of the region is essential.

Clinical usefulness of orbital and facial Time-Resolved Imaging of Contrast KineticS (TRICKS) magnetic resonance angiography.

PURPOSE: The clinical usefulness of orbital and facial Time-Resolved Imaging of Contrast KineticS (TRICKS) MRI was assessed quantitatively and qualitatively. METHODS: A retrospective chart review of the years 2001 to 2011 was conducted at the University of Wisconsin, Madison. Patients were selected based on tumor location (extracranial head and neck) and evaluation with TRICKS imaging at any stage of the clinical course. The TRICKS protocol presented in this article allows measurement of specific tumor characteristics including lesion morphology, vascular anatomy, flow dynamics within the lesion, rapidity and sequential nature of contrast enhancement, and lesion distensibility. Cases involving changes in diagnoses and/or management as a result of TRICKS interpretation are presented in detail. RESULTS: The imaging records of 49 patients were reviewed. Most lesions were located in or around the orbit (32 lesions, 65%). Benign vascular tumors comprised the largest subcategory (32 lesions, 65%) in the cohort. Of the 20 cases with histopathological data, interpretation of MRI with TRICKS magnetic resonance angiography successfully predicted 17 (85%). Characteristic enhancement patterns for the most commonly encountered lesions are presented, in addition to a qualitative analysis of how TRICKS contributed to select cases. TRICKS helped clarify diagnosis and/or redirect management in 19 of the 49 cases in this series. CONCLUSION: To the best of the authors' knowledge, this is the largest study to date of patients evaluated with TRICKS MRI/magnetic resonance angiography for orbital and facial tumors. MRI with TRICKS magnetic resonance angiography imaging protocol offers a minimally invasive, safe, and effective diagnostic instrument in selected patients with clinical diagnostic uncertainty and in those patients requiring high-resolution vascular mapping for management planning.

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.