OTOLARYNGOLOGY HEAD AND NECK SURGERY ANZJSurg.com
Systematic method for initial rapid analysis of maxillofacial computed tomography scans for surgeons in training Brad David Denney and Peter R. Ray Department of Plastic Surgery, University of Alabama at Birmingham, Birmingham, Alabama, USA
Key words CT, facial fracture. Correspondence Dr Brad David Denney, Department of Plastic Surgery, University of Alabama at Birmingham, 510 20th Street South, FOT 1102, Birmingham, AL 35294, USA. Email: [email protected] B. D. Denney MD; P. R. Ray MD. Accepted for publication 12 April 2015. doi: 10.1111/ans.13182
Abstract Background: Reading maxillofacial computed tomography (CT) scans is a basic skill for any surgeon who operates on the face. A standard systematic approach for how to read a maxillofacial CT scan from a surgeon’s perspective is lacking in literature, particularly for those in the early stages of training. We present a method of initial rapid analysis which our residents in training have responded to and report to be conceptually simple to apply. Methods: The senior author reviewed over 250 consults for face trauma and performed a detailed composite of the most common elements of each consult as well as the clinically relevant decision points. These elements were then bundled into a conceptual sketch of the skull-face-mandible with an accompanying standardized clinical data list. The new residents were then guided through a systematic approach to reading the scans while sketching the injuries identified. The authors then performed a survey to establish if the new method was helpful to early learners prior to and after adoption of the method. The survey consisted of five questions regarding the utility of the method for analysis of reading maxillofacial CT. Results: In total, seven residents were surveyed; 100% thought the technique made reading facial CT easier, 100% thought this method was easy to teach to junior residents and 86% found the analysis of facial CT easier and helped their surgical decision making. Conclusion: We present a systematic method for surgeons to evaluate facial CT scans. This is the first published account of methodology for maxillofacial CT analysis for surgeons.
Introduction A critical skill that is required early in the training of a plastic surgery resident is the ability to read maxillofacial computed tomography (CT) scans, as face trauma call remains an integral part of almost all programmes in the United States. The surgeon’s view of the facial CT scan differs from that of the radiologist and proper interpretation is not merely a cataloguing of the location of the broken bones. The high definition of today’s scanners allow for small, clinically irrelevant fractures of the facial skeleton to be visualized.1 From informal discussions with medical students and surgeons in training from other institutions, it became clear to the authors that surgical interpretation of facial CT scans is not taught in medical school or in general surgery training programmes. This lack of knowledge can be intimidating to the junior resident taking their first face trauma call under duress to make educated clinical deci© 2015 Royal College of Surgeons ANZ J Surg 86Australasian (2016) 184–187
sions immediately. The purpose of this paper is to provide a simple, systematic method for surgeons to rapidly analyse maxillofacial CT in order to establish a starting point for further deeper learning throughout their plastic surgery training. A new plastic surgery resident (one with less than 3 months of training) is often presented with a radiologist’s interpretation of a maxillofacial CT and the service is being consulted by the ER or the Trauma Service. However, maxillofacial CT findings serve different functions for a given physician depending on their role in the patient’s care. For example, the ER/trauma surgeon needs to know if everything is normal or if the findings warrant a consult as they seek to balance out unnecessary consults versus being negligent in the work up of an injury. The radiologist focuses on identifying normal or abnormal anatomy but does not factor in the importance or surgical indications (i.e. what is operative, what is urgent and what is non-operative). It can be difficult for the radiologist to know which ANZ J Surg •• (2015) ••–•• © 2015 Royal Australasian College of Surgeons
2Analysis of maxillofacial scans
Denney and Ray 185
fractures are important to point out to the surgeon.1 Therefore, understanding of the anatomically relevant and surgically accessible craniofacial buttresses is critical for the management of facial fracture injuries. This can be difficult in patients with multiple fractures in which it is important to distinguish those fractures that are surgically relevant. In a paper by Guimaraes, the most common trainee misinterpretation of facial CT was facial fractures, highlighting further the importance of a systematic method for maxillofacial CT analysis.2
Methods Early in the academic year, the senior author, a craniofacial plastic surgeon, presented a Plastic Surgery Grand Rounds to the entire department including all residents. The presentation includes a systematic method for rapid analysis of maxillofacial CT. After most junior residents had completed their first face calls, a survey was distributed to all plastic surgery residents within our institution. The plastic surgery residency programme at the University of Alabama at Birmingham is a traditional programme with a total of six residents, two per each class. All residents surveyed matriculated from general surgery backgrounds. Rapid analysis of on-call facial CT starts with a history and physical examination distilling the most important elements to convey to the attending on-call: age, coagulation status/bleeding issues and dentition. These three particular elements are crucial as they can dramatically change the operative plan. Age is obviously critical as paediatric facial fractures require a different treatment algorithm from that of an adult. Coagulation status is important due to the potential for significant blood loss with facial fracture repair and soft tissue dissection. This category also includes bleeding issues such as abdominal, thoracic or cranial bleeding that is being actively managed by other specialties. Finally, the management of edentulous mandible fractures differs considerably from those with full dentition and as such must be considered in the treatment plan.3 Our method for systematic facial CT analysis always starts with the coronal scan. On the first scroll through, the resident is instructed to follow the mandible, take note of normal foraminae and check condyle location as well as the status of the condylar neck. While scrolling backwards through the images, the resident inspects the maxillary buttresses. This conceptualizes the facial skeleton as a series of buttresses that serve to support both the form and function of the face.4 The noted abnormalities are sketched onto an easily drawn symbolic template of the face on an index card or a rounds sheet (Fig. 1). On the second scroll through, again using the coronal images, the resident now follows the orbital floors and checks the maxillary sinuses for fluid (blood). The presence of air in the periorbital space is identified if present. The medial or lateral dislocation of the frontozygomatic suture is carefully examined. The final detail inspected is the naso-orbital-ethmoid region, the area with the most frequent site of a missed or unrecognized injury as well as one of the most difficult fracture patterns to accurately repair.5 The second phase is to analyse the axial scans. The first skeletal element evaluated is the zygoma (at the frontozygomatic suture line, at its articulation with the sphenoid wing and its arch). Next, the nasoethmoid region is re-examined in this different plane and © 2015 Royal Australasian College of Surgeons
Fig. 1. Functional facial sketch.
Fig. 2. Coronal view algorithm.
Fig. 3. Axial view algorithm.
Fig. 4. Functional facial sketch with hash marks denoting fracture lines. Single denotes non-displaced whereas double represents displaced.
© 2015 Royal Australasian College of Surgeons
Analysis of maxillofacial scans 186
3 Denney and Ray
Fig. 5. Graphic analysis of resident’s response.
frontonasal ducts are traced from origin to termination from top to bottom and from bottom to top. On the second scroll down look, the pterygoids are noted for indirect evidence of a LeFort fracture, blood in the sinuses is noted as an indirect sign of orbital floor injury and the septum is evaluated for signs of hematoma as well as acute or prior fracture. Figures 2 and 3 provide the algorithm in outline form. Residents at our institution keep these images in their phones for quick reference while on-call. The teaching method includes visual © 2015 Royal Australasian College of Surgeons
cues, storylines and checklists in order to maximize the ability of any learner to absorb the topic. Prior to analysing the CT scan, the image in Figure 1 is drawn. This sketch takes eight strokes and less than 30 s to draw. Any fractures noted while systematically reading the CT scan are labelled with hatch marks as seen in Figure 4. This allows for a simple, common picture that allows for easy communication between the attending surgeon and junior resident. A photo of the diagram can be © 2015 Royal Australasian College of Surgeons
4Analysis of maxillofacial scans
taken and text messaged as it is de-identified and this facilitates easy communication between residents and the attending.
Results Figure 5 is a survey of five questions distributed to all residents at the beginning of the academic year after their first face call. The questions are meant to assess the effectiveness of rapid analysis of on-call facial CT scans. Seven residents in total were surveyed, 57% had never used a systematic method to review facial CT prior to learning of this particular method, 86% adopted this format as their method of choice for analysis, 100% thought the technique made reading facial CT easier, 100% thought this method was easy to teach to junior residents and 86% found reading facial CT to be much easier and helped their surgical decision making. The questions and results to the survey are displayed in Figure 5.
Conclusions The analysis of facial CT is a core competency skill for plastic surgery residents to acquire early in their training. It is likely to be integrated into the formal curriculum by the American College of Graduate Medication oversight committees in the future. However, literature on how surgeons should analyse facial CT is sparse. The methodology presented earlier for rapid initial analysis of facial CTs is designed to focus the reader (particularly one without significant experience) on what is surgically relevant in a simple, systematic and reproducible method. The algorithm focuses attention on the clinically relevant four transverse and four paired vertical buttresses. These buttresses are structural units of support for the face and fracture displacement is typically treated with reduction and internal fixation.1 The anatomy and clinical relevance of the buttresses is quickly reinforced with hands on operative experience for the on-call resident. It is well received by our residents and they report it to be helpful in their clinical duties. Our survey of residents presents data that show the effectiveness of this method. The first question highlights the expected lack of knowledge the plastic surgery residents have with regard to systematically reading facial CTs. One of the core teaching principles of plastic surgery training is to develop an organized mind to approach complex problems. A majority, 57%, of respondents began the academic year without a methodology for analysis. Most experienced surgeons develop an unconscious pattern in their analysis over time. The method we present offers the new surgeon a simple template upon which they can build their own unique strategy. After receiving education on rapid analysis of facial CT, 86% adopted this method as their primary means of reading facial CT. We do not require them to use this method if it does not work for them. Furthermore, 100% now find reading facial CT easier to analyse and teach and 86% self-report being more able to discern surgically relevant findings on facial CT. The technical term for such a method in design theory is an ‘advance organizer’. Discussion of design theory and its relevance to plastic surgery education is beyond the scope of this
© 2015 Royal Australasian College of Surgeons
Denney and Ray 187
article. It does, however, fundamentally differ from other approaches such as traditional teaching via web-based programs used by our radiology colleagues.6 Our method focuses the learner on identifying the abnormal in an effort to reduce the reported discrepancy found between resident and staff interpretations of images as they relate to findings (12.2% versus 1.5%).7 Another advantage with this method is it provides a quick and effective means of communication between attending and resident, attending to attending or for documentation in medical charts. In our programme, residents can send a text message to the attendings of the functional facial sketch with hash marks denoting fractures for a concise image detailing the extent of injury and providing a quick roadmap for operative plan. The attending and the resident can then review the CT together and reconcile areas missed or validate findings. We have also been approved by our institution to incorporate the functional facial sketch into our electronic medical record for documentation of surgically relevant facial fractures (Fig. 1). A drawback to this study is the small sample size. Obviously, sampling seven residents from one training institution may not be representative for all plastic surgery residents. However, the presented method with the aforementioned supporting data is an excellent starting point for a subject previously unexplored in literature. Moving forward in surgical education, with limits on time and resources, faculty are obligated to explore more effective teaching methods and this represents one such effort. We present a systematic method for surgeons to evaluate facial CT scans. Survey results indicate it is reproducible, effective and easy to teach. This is the first published account of methodology for facial CT analysis for surgeons in training and we think it could be universally adopted as a teachable method for new surgeons in training to shorten the learning curve associated with reading maxillofacial CTs.
References 1. Hopper RA, Salemy S, Sze RW. Diagnosis of midface fractures with CT: what the surgeon needs to know. Radiographics 2006; 26: 783–93. 2. Guimaraes C, Leach J, Jones B. Trainee misinterpretations on pediatric neuroimaging studies: classification, imaging analysis, and outcome assessment. AJNR Am. J. Neuroradiol. 2011; 32: 1591–9. 3. Franciosi E, Mazzaro E, Larranga J, Rios A, Picco P, Figari M. Treatment of edentulous mandibular fractures with rigid internal fixation: case series and literature review. Craniomaxillofac. Trauma Reconstr. 2014; 7: 35–42. 4. Gruss JS, MacKinnon SE. Complex maxillary fractures: role of buttress reconstruction and immediate bone grafts. Plast. Reconstr. Surg. 1986; 78: 9–22. 5. Markowitz BL, Manson PN, Sargent L et al. Management of the medial canthal tendon in nasoethmoid orbital fractures: the importance of the central fragment in classification and treatment. Plast. Reconstr. Surg. 1991; 87: 843–53. 6. Hassan B, Jacobs R, Scarfe W, Al-Rawi W. A web-based instruction module for interpretation of craniofacial cone beam CT anatomy. Dentomaxillofac. Radiol. 2007; 36: 348–55. 7. Wysoki MG, Nassar CJ, Koenigsberg RA, Novelline RA, Faro SH, Faerber EN. Head trauma: CT scan interpretation by radiology residents versus staff radiologists. Radiology 1998; 208: 125–8.
© 2015 Royal Australasian College of Surgeons
Systematic method for initial rapid analysis of maxillofacial computed tomography scans for surgeons in training Brad David Denney and Peter R. Ray Department of Plastic Surgery, University of Alabama at Birmingham, Birmingham, Alabama, USA
Key words CT, facial fracture. Correspondence Dr Brad David Denney, Department of Plastic Surgery, University of Alabama at Birmingham, 510 20th Street South, FOT 1102, Birmingham, AL 35294, USA. Email: [email protected] B. D. Denney MD; P. R. Ray MD. Accepted for publication 12 April 2015. doi: 10.1111/ans.13182
Abstract Background: Reading maxillofacial computed tomography (CT) scans is a basic skill for any surgeon who operates on the face. A standard systematic approach for how to read a maxillofacial CT scan from a surgeon’s perspective is lacking in literature, particularly for those in the early stages of training. We present a method of initial rapid analysis which our residents in training have responded to and report to be conceptually simple to apply. Methods: The senior author reviewed over 250 consults for face trauma and performed a detailed composite of the most common elements of each consult as well as the clinically relevant decision points. These elements were then bundled into a conceptual sketch of the skull-face-mandible with an accompanying standardized clinical data list. The new residents were then guided through a systematic approach to reading the scans while sketching the injuries identified. The authors then performed a survey to establish if the new method was helpful to early learners prior to and after adoption of the method. The survey consisted of five questions regarding the utility of the method for analysis of reading maxillofacial CT. Results: In total, seven residents were surveyed; 100% thought the technique made reading facial CT easier, 100% thought this method was easy to teach to junior residents and 86% found the analysis of facial CT easier and helped their surgical decision making. Conclusion: We present a systematic method for surgeons to evaluate facial CT scans. This is the first published account of methodology for maxillofacial CT analysis for surgeons.
Introduction A critical skill that is required early in the training of a plastic surgery resident is the ability to read maxillofacial computed tomography (CT) scans, as face trauma call remains an integral part of almost all programmes in the United States. The surgeon’s view of the facial CT scan differs from that of the radiologist and proper interpretation is not merely a cataloguing of the location of the broken bones. The high definition of today’s scanners allow for small, clinically irrelevant fractures of the facial skeleton to be visualized.1 From informal discussions with medical students and surgeons in training from other institutions, it became clear to the authors that surgical interpretation of facial CT scans is not taught in medical school or in general surgery training programmes. This lack of knowledge can be intimidating to the junior resident taking their first face trauma call under duress to make educated clinical deci© 2015 Royal College of Surgeons ANZ J Surg 86Australasian (2016) 184–187
sions immediately. The purpose of this paper is to provide a simple, systematic method for surgeons to rapidly analyse maxillofacial CT in order to establish a starting point for further deeper learning throughout their plastic surgery training. A new plastic surgery resident (one with less than 3 months of training) is often presented with a radiologist’s interpretation of a maxillofacial CT and the service is being consulted by the ER or the Trauma Service. However, maxillofacial CT findings serve different functions for a given physician depending on their role in the patient’s care. For example, the ER/trauma surgeon needs to know if everything is normal or if the findings warrant a consult as they seek to balance out unnecessary consults versus being negligent in the work up of an injury. The radiologist focuses on identifying normal or abnormal anatomy but does not factor in the importance or surgical indications (i.e. what is operative, what is urgent and what is non-operative). It can be difficult for the radiologist to know which ANZ J Surg •• (2015) ••–•• © 2015 Royal Australasian College of Surgeons
2Analysis of maxillofacial scans
Denney and Ray 185
fractures are important to point out to the surgeon.1 Therefore, understanding of the anatomically relevant and surgically accessible craniofacial buttresses is critical for the management of facial fracture injuries. This can be difficult in patients with multiple fractures in which it is important to distinguish those fractures that are surgically relevant. In a paper by Guimaraes, the most common trainee misinterpretation of facial CT was facial fractures, highlighting further the importance of a systematic method for maxillofacial CT analysis.2
Methods Early in the academic year, the senior author, a craniofacial plastic surgeon, presented a Plastic Surgery Grand Rounds to the entire department including all residents. The presentation includes a systematic method for rapid analysis of maxillofacial CT. After most junior residents had completed their first face calls, a survey was distributed to all plastic surgery residents within our institution. The plastic surgery residency programme at the University of Alabama at Birmingham is a traditional programme with a total of six residents, two per each class. All residents surveyed matriculated from general surgery backgrounds. Rapid analysis of on-call facial CT starts with a history and physical examination distilling the most important elements to convey to the attending on-call: age, coagulation status/bleeding issues and dentition. These three particular elements are crucial as they can dramatically change the operative plan. Age is obviously critical as paediatric facial fractures require a different treatment algorithm from that of an adult. Coagulation status is important due to the potential for significant blood loss with facial fracture repair and soft tissue dissection. This category also includes bleeding issues such as abdominal, thoracic or cranial bleeding that is being actively managed by other specialties. Finally, the management of edentulous mandible fractures differs considerably from those with full dentition and as such must be considered in the treatment plan.3 Our method for systematic facial CT analysis always starts with the coronal scan. On the first scroll through, the resident is instructed to follow the mandible, take note of normal foraminae and check condyle location as well as the status of the condylar neck. While scrolling backwards through the images, the resident inspects the maxillary buttresses. This conceptualizes the facial skeleton as a series of buttresses that serve to support both the form and function of the face.4 The noted abnormalities are sketched onto an easily drawn symbolic template of the face on an index card or a rounds sheet (Fig. 1). On the second scroll through, again using the coronal images, the resident now follows the orbital floors and checks the maxillary sinuses for fluid (blood). The presence of air in the periorbital space is identified if present. The medial or lateral dislocation of the frontozygomatic suture is carefully examined. The final detail inspected is the naso-orbital-ethmoid region, the area with the most frequent site of a missed or unrecognized injury as well as one of the most difficult fracture patterns to accurately repair.5 The second phase is to analyse the axial scans. The first skeletal element evaluated is the zygoma (at the frontozygomatic suture line, at its articulation with the sphenoid wing and its arch). Next, the nasoethmoid region is re-examined in this different plane and © 2015 Royal Australasian College of Surgeons
Fig. 1. Functional facial sketch.
Fig. 2. Coronal view algorithm.
Fig. 3. Axial view algorithm.
Fig. 4. Functional facial sketch with hash marks denoting fracture lines. Single denotes non-displaced whereas double represents displaced.
© 2015 Royal Australasian College of Surgeons
Analysis of maxillofacial scans 186
3 Denney and Ray
Fig. 5. Graphic analysis of resident’s response.
frontonasal ducts are traced from origin to termination from top to bottom and from bottom to top. On the second scroll down look, the pterygoids are noted for indirect evidence of a LeFort fracture, blood in the sinuses is noted as an indirect sign of orbital floor injury and the septum is evaluated for signs of hematoma as well as acute or prior fracture. Figures 2 and 3 provide the algorithm in outline form. Residents at our institution keep these images in their phones for quick reference while on-call. The teaching method includes visual © 2015 Royal Australasian College of Surgeons
cues, storylines and checklists in order to maximize the ability of any learner to absorb the topic. Prior to analysing the CT scan, the image in Figure 1 is drawn. This sketch takes eight strokes and less than 30 s to draw. Any fractures noted while systematically reading the CT scan are labelled with hatch marks as seen in Figure 4. This allows for a simple, common picture that allows for easy communication between the attending surgeon and junior resident. A photo of the diagram can be © 2015 Royal Australasian College of Surgeons
4Analysis of maxillofacial scans
taken and text messaged as it is de-identified and this facilitates easy communication between residents and the attending.
Results Figure 5 is a survey of five questions distributed to all residents at the beginning of the academic year after their first face call. The questions are meant to assess the effectiveness of rapid analysis of on-call facial CT scans. Seven residents in total were surveyed, 57% had never used a systematic method to review facial CT prior to learning of this particular method, 86% adopted this format as their method of choice for analysis, 100% thought the technique made reading facial CT easier, 100% thought this method was easy to teach to junior residents and 86% found reading facial CT to be much easier and helped their surgical decision making. The questions and results to the survey are displayed in Figure 5.
Conclusions The analysis of facial CT is a core competency skill for plastic surgery residents to acquire early in their training. It is likely to be integrated into the formal curriculum by the American College of Graduate Medication oversight committees in the future. However, literature on how surgeons should analyse facial CT is sparse. The methodology presented earlier for rapid initial analysis of facial CTs is designed to focus the reader (particularly one without significant experience) on what is surgically relevant in a simple, systematic and reproducible method. The algorithm focuses attention on the clinically relevant four transverse and four paired vertical buttresses. These buttresses are structural units of support for the face and fracture displacement is typically treated with reduction and internal fixation.1 The anatomy and clinical relevance of the buttresses is quickly reinforced with hands on operative experience for the on-call resident. It is well received by our residents and they report it to be helpful in their clinical duties. Our survey of residents presents data that show the effectiveness of this method. The first question highlights the expected lack of knowledge the plastic surgery residents have with regard to systematically reading facial CTs. One of the core teaching principles of plastic surgery training is to develop an organized mind to approach complex problems. A majority, 57%, of respondents began the academic year without a methodology for analysis. Most experienced surgeons develop an unconscious pattern in their analysis over time. The method we present offers the new surgeon a simple template upon which they can build their own unique strategy. After receiving education on rapid analysis of facial CT, 86% adopted this method as their primary means of reading facial CT. We do not require them to use this method if it does not work for them. Furthermore, 100% now find reading facial CT easier to analyse and teach and 86% self-report being more able to discern surgically relevant findings on facial CT. The technical term for such a method in design theory is an ‘advance organizer’. Discussion of design theory and its relevance to plastic surgery education is beyond the scope of this
© 2015 Royal Australasian College of Surgeons
Denney and Ray 187
article. It does, however, fundamentally differ from other approaches such as traditional teaching via web-based programs used by our radiology colleagues.6 Our method focuses the learner on identifying the abnormal in an effort to reduce the reported discrepancy found between resident and staff interpretations of images as they relate to findings (12.2% versus 1.5%).7 Another advantage with this method is it provides a quick and effective means of communication between attending and resident, attending to attending or for documentation in medical charts. In our programme, residents can send a text message to the attendings of the functional facial sketch with hash marks denoting fractures for a concise image detailing the extent of injury and providing a quick roadmap for operative plan. The attending and the resident can then review the CT together and reconcile areas missed or validate findings. We have also been approved by our institution to incorporate the functional facial sketch into our electronic medical record for documentation of surgically relevant facial fractures (Fig. 1). A drawback to this study is the small sample size. Obviously, sampling seven residents from one training institution may not be representative for all plastic surgery residents. However, the presented method with the aforementioned supporting data is an excellent starting point for a subject previously unexplored in literature. Moving forward in surgical education, with limits on time and resources, faculty are obligated to explore more effective teaching methods and this represents one such effort. We present a systematic method for surgeons to evaluate facial CT scans. Survey results indicate it is reproducible, effective and easy to teach. This is the first published account of methodology for facial CT analysis for surgeons in training and we think it could be universally adopted as a teachable method for new surgeons in training to shorten the learning curve associated with reading maxillofacial CTs.
References 1. Hopper RA, Salemy S, Sze RW. Diagnosis of midface fractures with CT: what the surgeon needs to know. Radiographics 2006; 26: 783–93. 2. Guimaraes C, Leach J, Jones B. Trainee misinterpretations on pediatric neuroimaging studies: classification, imaging analysis, and outcome assessment. AJNR Am. J. Neuroradiol. 2011; 32: 1591–9. 3. Franciosi E, Mazzaro E, Larranga J, Rios A, Picco P, Figari M. Treatment of edentulous mandibular fractures with rigid internal fixation: case series and literature review. Craniomaxillofac. Trauma Reconstr. 2014; 7: 35–42. 4. Gruss JS, MacKinnon SE. Complex maxillary fractures: role of buttress reconstruction and immediate bone grafts. Plast. Reconstr. Surg. 1986; 78: 9–22. 5. Markowitz BL, Manson PN, Sargent L et al. Management of the medial canthal tendon in nasoethmoid orbital fractures: the importance of the central fragment in classification and treatment. Plast. Reconstr. Surg. 1991; 87: 843–53. 6. Hassan B, Jacobs R, Scarfe W, Al-Rawi W. A web-based instruction module for interpretation of craniofacial cone beam CT anatomy. Dentomaxillofac. Radiol. 2007; 36: 348–55. 7. Wysoki MG, Nassar CJ, Koenigsberg RA, Novelline RA, Faro SH, Faerber EN. Head trauma: CT scan interpretation by radiology residents versus staff radiologists. Radiology 1998; 208: 125–8.
© 2015 Royal Australasian College of Surgeons
