Multiparametric Imaging for Presurgical Planning of Craniopagus Twins: The Experience of Two Tertiary Pediatric Hospitals with Six Sets of Twins.

Conjoined twins are rare and pose a challenge to radiologists and surgeons. Craniopagus twins, where conjunction involves the cranium, are especially rare. Even in large pediatric centers, radiologists are unlikely to encounter more than one such event in their medical careers. This rarity makes it daunting to select a CT and MRI protocol for these infants. Using the experience of two tertiary pediatric hospitals with six sets of craniopagus twins, this multidisciplinary and multimodal integrated imaging approach highlights the key questions that need addressing in the decision-making process for possible surgical intervention.

Automated 3D MRI rendering of the craniofacial skeleton: using ZTE to drive the segmentation of black bone and FIESTA-C images.

PURPOSE: Automated bone segmentation from MRI datasets would have a profound impact on clinical utility, particularly in the craniofacial skeleton where complex anatomy is coupled with radiosensitive organs. Techniques such as gradient echo black bone (GRE-BB) and short echo time (UTE, ZTE) have shown potential in this quest. The objectives of this study were to ascertain (1) whether the high-contrast of zero echo time (ZTE) could drive segmentation of high-resolution GRE-BB data to enhance 3D-output and (2) if these techniques could be extrapolated to ZTE driven segmentation of a routinely used non bone-specific sequence (FIESTA-C). METHODS: Eleven adult volunteers underwent 3T MRI examination with sequential acquisition of ZTE, GRE-BB and FIESTA-C imaging. Craniofacial bone segmentation was performed using a fully automated segmentation algorithm. Segmentation was completed individually for GRE-BB and a modified version of the algorithm was subsequently implemented, wherein the bone mask yielded by ZTE segmentation was used to initialise segmentation of GRE-BB. The techniques were subsequently applied to FIESTA-C datasets. The resulting 3D reconstructions were evaluated for areas of unexpected bony defects and discrepancies. RESULTS: The automated segmentation algorithm yielded acceptable 3D outputs for all GRE-BB datasets. These were enhanced with the modified algorithm using ZTE as a driver, with improvements in areas of air/bone interface and dense muscular attachments. Comparable results were obtained with ZTE+FIESTA-C. CONCLUSION: Automated 3D segmentation of the craniofacial skeleton is enhanced through the incorporation of a modified segmentation algorithm utilising ZTE. These techniques are transferrable to FIESTA-C imaging which offers reduced acquisition time and therefore improved clinical utility.

Enhancing Distraction Osteogenesis With Carbon Fiber Reinforced Polyether Ether Ketone Bone Pins and a Three-Dimensional Printed Transfer Device to Permit Artifact-Free Three-Dimensional Magnetic Resonance Imaging.

OBJECTIVES: To: (1) design an artifact-free 3D-printed MR-safe temporary transfer device, (2) engineer bone-pins from carbon fiber reinforced polyether ether ketone (CFR-PEEK), (3) evaluate the imaging artifacts of CFR-PEEK, and (4) confirm the osteointegration potential of CFR-PEEK, thus enhancing 3D-planning of bony advancements in hemifacial microsomia using sequential magnetic resonance imaging (MRI). STUDY DESIGN: Engineered CRF-PEEK bone pins and a 3D printed ex-fix device were implanted into a sheep head and imaged with MRI and computed tomography . The osseointegration and bony compatibility potential of CFR-PEEK was assessed with scanning electron microscopy images of MC3T3 preosteoblast cells on the surface of the material. RESULTS: The CFR-PEEK pins resulted in a signal void equivalent to the dimension of the pin, with no adjacent areas of MR-signal loss or computed tomography artifact. MCT3 cells adhered and proliferated on the surface of the discs by forming a monolayer of cells, confirming compatibility and osseointegration potential. CONCLUSION: A 3D printed transfer device could be utilized temporarily during MRI to permit artifact-free 3D planning. CFR-PEEK pins eliminate imaging artifact permitting sequential MRI examination. In combination, this has the potential to enhance distraction osteogenesis, by permitting accurate three-dimensional planning without ionizing radiation.

Automated Segmentation of the Craniofacial Skeleton With "Black Bone" Magnetic Resonance Imaging.

Three-dimensional (3D) imaging of the craniofacial skeleton is integral in managing a wide range of bony pathologies. The authors have previously demonstrated the potential of "Black Bone" MRI (BB) as a non-ionizing alternative to CT. However, even in experienced hands 3D rendering of BB datasets can be challenging and time consuming. The objectives of this study were to develop and test a semi- and fully-automated segmentation algorithm for the craniofacial skeleton.Previously acquired adult volunteer (n = 15) BB datasets of the head were utilized. Imaging was initially 3D rendered with our conventional manual technique. An algorithm to remove the outer soft-tissue envelope was developed and 3D rendering completed with the processed datasets (semi-automated). Finally, a fully automated 3D-rendering method was developed and applied to the datasets. All 3D rendering was completed with Fovia High Definition Volume Rendering (Fovia Inc, Palo Alto, CA). Analysis was undertaken of the 3D visual results and the time taken for data processing and interactive manipulation.The mean time for manual segmentation was 12.8 minutes, 3.1 minutes for the semi-automated algorithm, and 0 minutes for the fully automated algorithm. Further fine adjustment was undertaken to enhance the automated segmentation results, taking a mean time of 1.4 minutes.Automated segmentation demonstrates considerable potential, offering significant time saving in the production of 3D BB imaging in adult volunteers. the authors continue to undertake further development of our segmentation algorithms to permit adaption to the pediatric population in whom non-ionizing imaging confers the most potential benefit.

Black bone MRI with 3D reconstruction for the detection of skull fractures in children with suspected abusive head trauma.

PURPOSE: The purpose of this study was to determine the accuracy of "black bone" (BB) MRI for the detection of skull fractures in children with potential abusive head trauma. METHODS: A total of 34 pediatric patients were evaluated for potential abusive head trauma. All patients had both a non-contrast head CT (HCT) with multiplanar reformatted images and 3D volumetric reformatted images where available (gold standard) for fracture diagnosis and BB of the head with multiplanar reformatted images and 3D volumetric images. BB was performed using an ultrashort TE pointwise encoding time reduction with radial acquisition (PETRA) sequence at 1.5 T or 3 T. BB datasets were post-processed and 3D images created using Fovia's High Definition Volume Rendering® software. Two board-certified pediatric neuroradiologists independently reviewed the HCT and BB imaging, blinded to the findings from the other modality. RESULTS: Median patient age was 4 months (range 1.2-30 months). A total of 20 skull fractures in six patients (18% incidence of skull fractures) were detected on HCT. BB demonstrated 83% sensitivity (95%[CI] 36-99%), 100% specificity (95%[CI] 88-100%), 100% PPV (95%[CI] 46-100%), 97% NPV (95%[CI] 82-99%), and 97% accuracy (95%[CI] 85-99%) for diagnosis of a skull fracture. BB detected 95% (19/20) of the skull fractures detected by CT. CONCLUSION: A black bone MRI sequence may provide high sensitivity and specificity for detection of skull fractures in pediatric patients with abusive head trauma.

Three-Dimensional Reconstruction of the Craniofacial Skeleton With Gradient Echo Magnetic Resonance Imaging ("Black Bone"): What Is Currently Possible?

Three-dimensional (3D) reconstructed computed tomography (CT) imaging has become an integral component of craniomaxillofacial patient care. However, with increasing concern regarding the use of ionizing radiation, particularly in children with benign conditions who require repeated examinations, dose reduction and nonionizing alternatives are actively being sought. The "Black Bone" magnetic resonance imaging (MRI) technique provides uniform contrast of the soft tissues to enhance the definition of cortical bone. The aim of this study was to develop methods of 3D rendering of the craniofacial skeleton and to ascertain their accuracy. "Black Bone" MRI datasets acquired from phantoms, adult volunteers and patients were segmented and surface and/or volume rendered using 4 commercially available or open source software packages. Accuracy was explored using a custom phantom (permitting direct measurement), CT and MRI. "Black Bone" MRI datasets were successfully used to create 3D rendered images of the craniofacial skeleton in all 4 software packages. Comparable accuracy was achieved between CT and MRI 3D rendered images of the phantom. The "Black Bone" MRI technique provides a viable 3D alternative to CT examination when imaging the craniofacial skeleton.

The Significance of Squamosal Suture Synostosis.

The squamosal suture is one of the lateral minor skull sutures, separating the parietal and squamous temporal bones. While the phenotypic appearances and sequelae of synostosis of the major cranial vault sutures are well documented, little is reported concerning synostosis of the squamosal suture (SQS). The aim of this study was to determine the frequency of squamosal suture synostosis, and to document the significance of this entity.A retrospective review of the diagnostic imaging for all new pediatric patients (aged ≤16 years) referred to the Oxford Craniofacial Unit between January 2008 and February 2013 was completed to identify patients with SQS. Computed tomography (CT) imaging was available in 422 patients and the axial and three-dimensional reconstructed images reviewed.Squamosal suture synostosis was confirmed in 38 patients (9%). It was present in conjunction with major suture synostosis in 33 patients and in isolation in 5. The incidence increased with age. It was more common in patients with syndromic craniosynostosis (18%) and associated syndromic conditions (36%) than in those with isolated major suture synostosis (6%). It was found to occur with coronal, lambdoid, and sagittal synostosis, but was most frequent with multisuture fusion patterns. Squamosal suture synostosis was not associated with a consistent calvarial deformity either in isolation or when associated with a major suture fusion. No patient underwent surgery specifically to correct SQS.In conclusion, contrary to previous reports, squamosal suture synostosis is a relatively frequent finding in the general case mix of a typical craniofacial unit, but is of limited clinical significance.

"Black Bone" MRI: a potential alternative to CT with three-dimensional reconstruction of the craniofacial skeleton in the diagnosis of craniosynostosis.

OBJECTIVES: To determine the potential of novel gradient echo parameters, "Black Bone" MRI as an alternative to CT in the identification of normal and prematurely fused cranial sutures both in 2D and 3D imaging. METHODS: Thirteen children with a clinical diagnosis of craniosynostosis underwent "Black Bone" MRI in addition to routine cranial CT. "Black Bone" datasets were compared to CT and clinical findings. "Black Bone" imaging was subsequently used to develop 3D reformats of the craniofacial skeleton to enhance further visualisation of the cranial sutures. RESULTS: Patent cranial sutures were consistently identified on "Black Bone" MRI as areas of increased signal intensity. In children with craniosynostosis the affected suture was absent, whilst the remaining patent sutures could be visualised, consistent with CT and clinical findings. Segmentation of the "Black Bone" MRI datasets was successful with both threshold and volume rendering techniques. The cranial sutures, where patent, could be visualised throughout their path. CONCLUSIONS: Patent cranial sutures appear as areas of increased signal intensity on "Black Bone" MRI distinct from the cranial bone, demonstrating considerable clinical potential as a non-ionising alternative to CT in the diagnosis of craniosynostosis. KEY POINTS: • Patent cranial sutures appear hyperintense on "Black Bone" MRI • Prematurely fused cranial sutures are distinct from patent sutures • Minimal soft tissue contrast permits 3D-rendered imaging of the craniofacial skeleton.

Power spectral analysis of the effects of epinephrine, norepinephrine, dobutamine and dopexamine on microcirculation following free tissue transfer.

BACKGROUND: The use of pressor drugs after microsurgical free tissue transfer remains controversial because of potential vasoconstrictor effects on the free flap. Noninvasive monitoring of free flaps with laser Doppler flowmetry may provide further information regarding the local regulation of blood flow in the flap tissues during pressor infusions. This study evaluated the effects of four commonly used pressor agents. METHODS: Twenty four patients (25 data sets) undergoing head and neck cancer resection and free flap reconstruction were recruited. Epinephrine, norepinephrine, dopexamine, and dobutamine were infused in a random order at four infusion rates, after surgery, with free flap and control area (deltoid region) laser Doppler skin blood flow monitoring. Frequency analysis of the Doppler waveform was performed utilizing the time period immediately before the first drug infusion for each patient as baseline. RESULTS: At baseline there was less power at the 0.002-0.6 Hz frequency in the flap compared with control tissue consistent with surgical denervation. At maximum epinephrine infusion rates, the control of blood flow moved toward (i.e., proportion of power increased in) the lower frequencies, as smooth muscle mediated (myogenic) control began to dominate blood flow, an effect most marked with norepinephrine. Dobutamine and dopexamine had little effect on control of blood flow. CONCLUSIONS: Denervation of free flap tissue is demonstrable using spectral analysis of laser Doppler blood flow signals. With norepinephrine the control of blood flow shifts toward low frequency vasomotion where blood flow depends mostly on average blood pressure, making it potentially the most suitable agent following free tissue transfer.

Identification of normal cranial sutures in infants on routine magnetic resonance imaging.

There are increasing concerns relating to the ionizing effects of computed tomography imaging in infants with benign conditions. Magnetic resonance imaging (MRI) is a potential alternative to ionizing radiation when determining patency of the cranial sutures; however, there is no documentation in the literature on the appearance of normal cranial sutures in infants on MRI. This study reviews the appearance of the cranial sutures, their widths, and accuracy of identification in the first year of life on MRI.The coronal, sagittal, and lambdoid sutures were evaluated by 5 assessors on 100 anonymized MRI scans in infants aged 1 to 361 days. The sutures were scored on a 3-point scale. The MRI sequences investigated were axial T1, axial T2, coronal fluid attenuated inversion recovery, axial short tau inversion recovery, and sagittal T1. The suture widths were measured in those cases where they were clearly identifiable, and agreement was obtained in the first aspect of the study (n = 38).A κ score of 0.6 was obtained for interrater agreement. An increasing total score for all sutures with advancing age was found (P < 0.05). The mean suture widths for the coronal, sagittal, and lambdoid sutures were 1.2 (SD, 0.4), 1.4 (SD, 0.4), and 1.3 (SD, 0.3) mm, respectively. There was no significant difference in suture width with age.The appearance of cranial sutures on MRI is as an area of signal void, which may be difficult to clearly define, thus making it unreliable as a standard investigation in the diagnosis of craniosynostosis.

A detailed anatomical assessment of the lateral tongue extrinsic musculature, and proximity to the tongue mucosal surface. Does this confirm the current TNM T4a muscular subclassification?

PURPOSE: The current T4a subclassification of the TNM staging system for oral malignancies has been criticised as based almost exclusively on anatomical data. The aim of this study was to provide anatomical confirmation of the muscular constraints of T4a classification of oral tongue tumours. METHODS: A detailed anatomical study describing and measuring the adjacency of the named extrinsic tongue muscles to the lateral tongue surface was completed on the Visible Human Female (VHF). The distance of styloglossus and hyoglossus to the over lying mucosa were determined. RESULTS: The appearance, position, orientation and anatomical relationships of the lateral tongue extrinsic muscles, with comparison to their classical descriptions are described. The right VHF styloglossus was 1.3 mm (0.33-1.48) and left 2.91 mm (0.66-7.68) from the mucosal surface in the axial plane. The right VHF hyoglossus was 2.93 mm (1.48-4.96) and left 4.33 (1.68-8.71) from the mucosal surface in the axial line. CONCLUSIONS: In the lateral tongue, styloglossus and hyoglossus are very superficial. The inclusion criteria of hyoglossus and styloglossus in the T4a staging does not appear justified based upon their anatomical position.

Temporomandibular disorders-review of evidence-based management and a proposed multidisciplinary care pathway.

Temporomandibular disorders (TMDs) are a prevalent but complex group of conditions that cause orofacial pain. Temporomandibular disorders are recognized as one of the most common chronic pain conditions, alongside back pain and headache disorders. Given the competing theories surrounding what causes TMDs and limited high-equality evidence on optimally treating TMDs, clinicians often encounter challenges in developing an effective management plan for patients. Furthermore, patients will often seek advice from multiple health care providers from varying specialties, seeking curative management, often resulting in inappropriate treatments and no improvement in pain symptoms. Throughout this review, we explore the existing evidence base surrounding the pathophysiology, diagnosis, and management of TMDs. An existing United Kingdom-based multidisciplinary care pathway for the management of TMDs is described herein, highlighting the benefits of a multidisciplinary approach to patient care for TMDs.

Functional fibrinogen to platelet ratio using thromboelastography as a predictive parameter for thrombotic complications following free tissue transfer surgery: a preliminary study.

BACKGROUND: Microvascular free tissue transfer in head and neck surgery has become an indispensable tool. Anastomotic thrombosis is one of the leading causes of flap failure; however, there are no validated methods to accurately identify and quantify those patients most at risk of thrombotic complications. The aim of this study was to determine if functional fibrinogen to platelet ratio using thrombelastography could preoperatively identify patients at risk of thrombotic complications. MATERIALS AND METHODS: Twenty nine patients undergoing free tissue transfer surgery for head and neck pathology underwent routine TEG® analysis, with calculation of functional fibrinogen to platelet ratio at induction of anesthesia. All perioperative thrombotic complications were recorded and crossreferenced with preoperative ratios. Data was further compared to results obtained from 42 healthy volunteers. RESULTS: The mean functional fibrinogen to platelet ratio was significantly higher in the surgery group compared to healthy volunteers. Of the 29 patients studied, 31% (n = 9) had some form of thrombotic event, with all but one patient having a ratio ≥42% (mean 47% ± 7%). For those patients without thrombotic events, the mean ratio was 37% ± 5%. CONCLUSION: A functional fibrinogen to platelet ratio above 42% as measured by TEG® may be useful in identifying those patients likely to develop thrombotic complication.

Imaging of Bone in the Head and Neck Region, is There More Than CT?

Purpose of Review: The objective of this review is to document the advances in non-ionising imaging alternatives to CT for the head and neck. Recent Findings: The main alternative to CT for imaging bone of the head and neck region is MRI, particularly techniques which incorporate gradient echo imaging (Black Bone technique) and ultra-short or zero-echo time imaging. Since these techniques can provide high resolution isometric voxels, they can be used to provide multi-planar reformats and, following post processing, 3D reconstructed images of the craniofacial skeleton. As expected, the greatest advancements in recent years have been focused on enhanced image processing techniques and attempts to address the difficulties encountered at air-bone interfaces. Summary: This article will review the imaging techniques and recent advancements which are bringing non-ionising alternatives to CT imaging of the bone of the head and neck region into the realm of routine clinical application.

Quality improvement in action. Direct general practitioner referrals to audiology for the provision of hearing aids: a single centre review.

Direct referral audiology clinics (DRACs) for the assessment and provision of hearing aids in those over 60 years of age were initially introduced in the National Health Service (NHS) as a method to decrease outpatient waiting times and reduce demand on ear, nose and throat (ENT) appointments. We retrospectively reviewed the electronic records of 353 patients referred to the DRACs at our hospital over a four-month period to determine the continued benefits of a DRAC service, in terms of impact upon ENT appointments, and appropriate general practitioner (GP) use of the clinics. Of the 353 patients seen within the DRAC clinics, 320 were ultimately provided with a hearing aid. Fifty five patients required review by an otolaryngologist, either being referred directly by the audiology department or referred back to their GP for re-referral. The greatest lack of adherence to the referral criteria for DRAC appointments related to appropriate treatment of wax within the community, with two patients declining an aid when their perceived improvement in hearing was significant following microsuctioning. DRACs appear to continue to provide a cost-benefit to the NHS, reducing demand on ENT appointments, but further improvements could be made within primary care to further utilise this service.

What the general dental practitioner needs to know about HPV-related oropharyngeal malignancy.

The rates of oropharyngeal squamous cell carcinoma have continued to rise secondary to the increasing prevalence of the human papillomavirus (HPV). HPV-related disease is typically found in younger patients who do not have the traditional risk factors for malignancy. General dental practitioners (GDPs) often examine patients regularly and may therefore have an opportunity to identify oropharyngeal malignancies at an early stage. However, many GDPs are unfamiliar with oropharyngeal anatomy, pathology and clinical examination. This review summarises the key points in identifying patients with oropharyngeal malignancy who necessitate urgent referral.

Reconstruction of a congenital nasal deformity using skin tags as a chondrocutaneous composite graft.

Nasal reconstruction has key functional aims of achieving an optimal esthetic result while maintaining a patent airway. For the distal third of the nose, these goals are achieved by replacement of lining, osseocartilaginous support, and soft tissue coverage. The use of skin tags for reconstruction of the ear have been well documented, yet to our knowledge, there are no reported cases of their use in reconstruction of the nose. Skin tags, also referred to as acrochordon, fibroepithelial polyps, and pedunculated fibromas are benign soft, fleshy, sessile, or pedunculated lesions ranging from 1 to 5 mm in diameter. We report a novel approach to distal nasal reconstruction that arose opportunistically as a result of coincident pathologies.

The evaluation of bony union after frontofacial distraction.

Frontofacial advancement by distraction osteogenesis using the rigid external distraction device has become an accepted treatment for the deformity associated with craniofacial dysostoses (e.g., Crouzon, Apert, and Pfeiffer syndromes). The technical and physiological principles of osteogenesis distraction are well understood. This study documents the pattern of calcification at the osteotomy sites after distraction by analysis of serial three-dimensional computed tomography (CT) scans. The CT scans of 25 patients (11 with Crouzon, 6 with Apert, and 8 with Pfeiffer syndrome) were analyzed. Eleven individual areas along the osteotomy lines were assessed for evidence of bone formation. Scores were assigned within 4 categories ranging from no bone, calcification without bridge formation, a bony bridge, to complete bony infill (>95%). The scans were reviewed on 2 separate occasions by 2 independent assessors. There was high concordance both for intraobserver and interobserver scores. Rigid external distraction frame removal was undertaken after a 6-week consolidation period. All CT scan timings were calculated from this date. Of the 25 patients studied, 16 patients had CT scans available at 3 to 6 months, 12 at 9 to 12 months, and 7 at or more than 18 months. The scans were available in standard coronal slices with three-dimensional reconstructions. Bone formation is most consistently seen in the pterygoid region with calcification consistently occurring earlier and more completely in this area. Bone formation was often delayed in the orbital region and severely delayed or absent in the frontal region and zygomatic arches. There was no significant difference in the order or quality of bony union for the 3 underlying craniofacial dysostoses. This preliminary study confirms the clinical impression that bone formation after distraction is greatest in the pterygoid regions. The clinical implications of these findings are discussed.

"Black Bone" MRI: a novel imaging technique for 3D printing.

OBJECTIVES: Three-dimensionally printed anatomical models are rapidly becoming an integral part of pre-operative planning of complex surgical cases. We have previously reported the "Black Bone" MRI technique as a non-ionizing alternative to CT. Segmentation of bone becomes possible by minimizing soft tissue contrast to enhance the bone-soft tissue boundary. The objectives of this study were to ascertain the potential of utilizing this technique to produce three-dimensional (3D) printed models. METHODS: "Black Bone" MRI acquired from adult volunteers and infants with craniosynostosis were 3D rendered and 3D printed. A custom phantom provided a surrogate marker of accuracy permitting comparison between direct measurements and 3D printed models created by segmenting both CT and "Black Bone" MRI data sets using two different software packages. RESULTS: "Black Bone" MRI was successfully utilized to produce 3D models of the craniofacial skeleton in both adults and an infant. Measurements of the cube phantom and 3D printed models demonstrated submillimetre discrepancy. CONCLUSIONS: In this novel preliminary study exploring the potential of 3D printing from "Black Bone" MRI data, the feasibility of producing anatomical 3D models has been demonstrated, thus offering a potential non-ionizing alterative to CT for the craniofacial skeleton.