List of Contributors

Muaaze Ahmad, MB ChB FRCR
Consultant Radiologist
The Royal London Hospital
Whitechapel
London
UK

Simon Barker, MB ChB FRCP FRCR
Consultant Neuroradiologist
Wessex Neurological Centre
Southampton General Hospital
Southampton, Hampshire
UK

Antonio Belli, MD FRCS FRCS(SN)
Senior Lecturer in Neurosurgery
Division of Clinical Neurosciences
University of Southampton
Southampton, Hampshire
UK

Clare L. Bent, MB BCh FRCR
Interventional Radiology Fellow
The Royal London Hospital
Whitechapel
London
UK

Mark P. Bernstein, MD
Assistant Professor of Radiology
Trauma and Emergency Radiology
NYU Medical Center/Bellevue Hospital
New York, NY
USA

Gavin Bowyer, MChir FRCS(Orth)
Consultant Orthopaedic Surgeon
Southampton University Hospitals NHS Trust
Southampton, Hampshire
UK

Mark W. Bowyer, MD FACS DMCC Colonel (Ret) USAF MC
Professor of Surgery
Chief, Division of Trauma and Combat Surgery Director of Surgical Simulation
The Norman M. Rich Department of Surgery
Uniformed Services University of the Health Sciences
Bethesda, MD
USA

Christopher Burns, MD LCMDR USN MC
Surgical Resident
National Naval Medical Center
Bethesda, MD
USA

Xzabia Caliste, MD
Surgical Resident
Department of Trauma and Acute Care Surgery
Washington Hospital Center
Washington, DC
USA

Howard Champion, LRCP MRCS DMCC FRCS
Professor of Surgery and Senior Adviser in Trauma
Uniformed Services University of the Health Sciences
Bethesda, MD
USA

Catherine Cord-Uday, MBBS FRACS(Paed Surg)
Consultant Surgeon
Flinders Medical Centre
Bedford Park
Adelaide, SA
Australia

Evan Davies, BM FRCS Ed(Tr & Orth)
Consultant Orthopaedic Surgeon
Southampton University Hospitals NHS Trust
Southampton, Hampshire
UK

David Elias, MBBS BSc MRCP FRCR
Consultant Musculoskeletal Radiologist
Department of Diagnostic Imaging
King’s College Hospital NHS Foundation Trust
London
UK

Peter K. Ellis, MB BCh MRCP FRCR FFRRCSI
Consultant Radiologist
Royal Victoria Hospital
Belfast, Northern Ireland
UK

Sivadas Ganeshalingam, MA MBBS FRCS FRCR
Radiology Fellow
The Royal London Hospital
Whitechapel
London
UK

David Gay, MB BS FRCR
Fellow in Musculoskeletal Radiology
Nuffield Orthopaedic Centre
Oxford, Oxfordshire
UK

Iain Gibb (Lieutenant Colonel), MB ChB FRCS FRCR RAMC
Consultant Radiologist and Army Consultant Advisor in Radiology
Royal Hospital Haslar
Gosport, Hampshire
UK

Mark Griffiths, MRCP FRCR
Consultant Radiologist
Southampton University Hospitals NHS Trust
Southampton, Hampshire
UK

Leonard J. King, MB ChB FRCP FRCR
Consultant Radiologist
Department of Radiology
Southampton University Hospitals NHS Trust
Southampton, Hampshire
UK

Graham Lloyd-Jones, BA MBBS MRCP FRCR
Specialist Registrar in Radiology
Southampton University Hospitals NHS Trust
Southampton, Hampshire
UK

Jason H. M. Macdonald, MB BS MRCP FRCR
Specialist Registrar in Neuroradiology
Wessex Neurological Centre
Southampton General Hospital
Southampton, Hampshire
UK

Matthew B. Matson, MRCP FRCR
Consultant Interventional Radiologist
Royal London Hospital
Whitechapel
London
UK

Niall Power, MRCPI FRCR
Consultant Radiologist
St Bartholomew’s and The Royal London Hospitals
London
UK

Anne G. Rizzo, MD FACS
Associate Professor of Surgery
Virginia Commonwealth University School of Medicine
Richmond, VA
USA; and
Uniformed Services University of the Health Sciences
Bethesda, MD
USA

James Ryan, OstJ MCh FRCS DMCC FFAEM(Hon)
Emeritus Professor of Conflict Recovery
University College London and St George’s University of London
London, UK; and
International Professor of Surgery
Uniformed Services University of the Health Sciences
Bethesda, MD
USA

Madeleine Sampson, MB ChB FRCP FRCR
Consultant Radiologist
Southampton University Hospitals NHS Trust
Southampton, Hampshire
UK

Richard A. Schaefer, MD MPH DMCC COL MC USA
Associate Professor of Surgery
Chief, Division of Orthopaedic Surgery
Norman M. Rich Department of Surgery
Uniformed Services University of the Health Sciences
Bethesda, MD
USA

James H. Street, MD
Department of Trauma and Acute Care Surgery
Washington Hospital Center
Washington, DC
USA

James Teh, MB BS BSc MRCP FRCR
Consultant Musculoskeletal Radiologist
Nuffield Orthopaedic Centre
Oxford, Oxfordshire
UK

Ioannis Vlahos, BSc MBBS MRCP FRCR
Consultant Thoracic Radiologist
St George’s NHS Trust
London, UK; and
Assistant Professor
New York University
New York, NY
USA

David C. Wherry, MD FACS FRCS LRCP DMCC
Professor of Surgery
Uniformed Services University of the Health Sciences
Bethesda, MD
USA

Foreword

Some four decades ago, as a recently qualified doctor, I managed victims of trauma without the benefit of trauma systems, without well tried management protocols and without today’s imaging technology. Digital imaging did not exist and “urgent” X-ray films were often still wet from the chemical processor, making interpretation less than optimal. Computed tomography and magnetic resonance imaging were still prototypes or on the physicist’s drawing board and ultrasound scanning was in its infancy. Digital, whole-body scanners, such as the Lodox Statscanner, were something approaching science fiction. In the intervening period between then and now, trauma care, like many other aspects of medicine, has progressed immeasurably, as has the part played by imaging technology and techniques.

It is incumbent on all who provide emergency, in-hospital trauma care to be aware of the current range of diagnostic and therapeutic techniques that radiology and radiologists bring to the management of trauma. This short, but comprehensive book, the ABC of Imaging in Trauma, will do exactly that.

After reading this book, medical personnel will have an understanding of current imaging concepts and their clinical relevance, a point well made by the book’s editors in their introductory chapter. They also go on to point out that the fundamental goals of imaging are assisting staff in quickly identifying the range and severity of injuries and, where possible, intervening to arrest life-threatening haemorrhage. They also endorse the point: imaging techniques are there to complement clinical skills and acumen, not to replace them.

The fundamental aim of this book is to act as a practical guide on the scope and interpretation of emergency imaging procedures used in assessing the severely injured. It more than achieves this in a host of ways, the more outstanding being: the key points summary boxes at the beginning of each chapter; discussion of relevant clinical and demographic information before going on to discuss imaging techniques; and the richness and quality of the illustrations and line diagrams. These factors also add to the ease of finding relevant information.

It is of some import that the last four chapters of this book cover paediatric trauma, imaging trauma in pregnancy, ballistics and blast injury and imaging of major incidents and mass casualty situations. Managing trauma in children and pregnant women can be particularly trying. This book provides a systematic review and excellent short guide to imaging techniques in both situations. Major incidents are now almost commonplace. Knowledge of the role of imaging in casualty triage in such incidents, is one key to saving lives. This book provides that knowledge.

Those who become victims of severe trauma, whether civilian or military, will have the best outcome if cared for by experienced, multidisciplinary teams working to well-tried protocols. One of these protocols is what this excellent book is about: a guide to the place of the many forms of imaging available in trauma management algorithms.

All who are interested in, or have a role in hospital-based trauma care, should read this book. It will make them better carers.

My own anticipation is that the next edition will be even better.

P. Roberts, CBE MS FRCS
Professor of Military Surgery Emeritus
Royal College of Surgeons of England
December 2009

Acknowledgments

The editors would like to thank Professor Norman Rich and the Department of Surgery at the Uniformed Services University of Health Sciences, Bethesda, Maryland, for their assistance in the production of this book, and Dr Graham Lloyd-Jones for his assistance in the production of illustrations.

CHAPTER 1
Introduction

Leonard J. King¹ and David C. Wherry²

¹Southampton University Hospitals NHS Trust, Southampton, Hampshire, UK

²Uniformed Services University of the Health Sciences, Bethesda, MD, USA

Trauma is a leading cause of morbidity and mortality in the developed world, accounting for 39 deaths per 100 000 population in the United States in 2005 and around 800 000 deaths per year in Europe. Deaths resulting from trauma typically follow a tri-modal distribution (Figure 1.1). The first peak, which accounts for 50% of all trauma deaths, occurs within the first few minutes after injury. Very few of these victims can be salvaged and thus prevention is the key to significantly decreasing the rate of immediate deaths. The second peak occurs from a few minutes up to several hours after injury, often due to uncontrolled bleeding, and accounts for 30% of trauma-related mortalities. With appropriate medical care many of these patients can be saved by prompt identification and management of correctable injuries. The last peak occurs days to weeks after the injury. Outcome during this period of late deaths depends in part on how cases are managed in the preceding periods.

Recognition that trauma care was previously fragmented and disorganized with poor outcomes has helped to stimulate innovations in trauma care including trained paramedics, advanced trauma life support (ATLS) training for surgeons and in-house response teams in many hospitals. These developments, supported by technological advances including imaging techniques, have led to an improvement in the quality of emergency care. Nevertheless, motor vehicular collisions, domestic and industrial accidents, assaults, gunshot wounds and injuries related to acts of terrorism continue to challenge the management of trauma by medical teams throughout the world.

During the hospital phase of resuscitation, modern technology and medical facilities should complement the physician’s clinical skills to improve decision making for trauma patients. There are a number of different imaging modalities that can be used to assist in the management of these patients, each with a variety of strengths and weaknesses. Plain radiographs remain a useful tool, particularly for the assessment of limb fractures and dislocations. In recent years, however, there have been significant developments in the imaging of major trauma, particularly with the introduction of multidetector computed tomography (MDCT), which allows rapid acquisition of detailed whole body cross-sectional imaging. Coupled with advances in post-processing techniques, MDCT now also allows the routine application of computer-generated high-quality multiplaner reformat (MPR) and three-dimensional volume-rendered images in addition to the axial plane images (Figure 1.2). This new technology has redefined the role of plain radiographs, ultrasound and computed tomography in the evaluation of victims of major trauma. At institutions where the full range of diagnostic imaging facilities are readily available, whole body MDCT has become the imaging investigation of choice in stable patients following the initial ATLS recommended trauma series (chest, lateral cervical spine and pelvis). Some trauma centres are also fortunate enough to have CT within the emergency department and are advocating CT for all but the most unstable trauma patients, a policy which is not suitable for many other hospitals where CT facilities are remote from the resuscitation area or may not be immediately available for an unstable trauma patient. In such circumstances and in more austere situations, alternative imaging strategies will need to be employed, including additional plain radiographs, ultrasound, intravenous urography and on-table in-theatre angiography.

Ultrasound has been used in the investigation of abdominal trauma since the 1970s and interest grew in the 1990s with the availability of hand-held ultrasound machines and the development of the limited focused assessment of sonography in trauma (FAST) technique (Figure 1.3). The FAST technique enables non-radiologists with limited training to perform a rapid ultrasound examination in the resuscitation room looking for free intraperitoneal fluid (Figure 1.4) with a reasonable degree of accuracy. FAST can be used to triage a haemodynamically unstable patient with significant free fluid to surgery; however, the absence of free fluid does not exclude a significant intra-abdominal injury requiring surgical intervention. Even in the hands of experienced observers the sensitivity of ultrasound for demonstrating organ lacerations and mesenteric or retroperitoneal injury is poor and thus it cannot be routinely used to exclude injury as a stand-alone technique. Where facilities are limited and no CT is available, a policy of admission for observation and repeat ultrasound by an experienced operator can be used but should not be considered best practice.

Imaging findings in conjunction with clinical assessment can be crucial in providing the critical information required to make key management decisions. Thus, an understanding of current trauma imaging concepts and their clinical relevance is essential for all medical personnel involved in the immediate hospital care of trauma patients whose outcome may depend on rapid assessment of the nature and severity of their injuries, allowing appropriate medical management and surgical and non-surgical intervention.

Although the precise role of imaging and the choice of modality will vary depending on the clinical scenario and the availability of equipment and local expertise, the fundamental goals remain the same – that is, assisting clinical staff in rapidly identifying the range and severity of injuries in the trauma patient and, where possible, intervening to arrest life-threatening haemorrhage with use of endovascular procedures. It is important for those involved in trauma care to recognize the place of imaging in relation to other clinical activities and how it fits into the clinical algorithm. The ATLS approach in trauma care is summarized in Box 1.1.

Figure 1.1 Graph illustrating the trimodal distribution of deaths following trauma. Graph taken from the ATLS Manual, 2005. Reproduced with the permission of the American College of Surgeons.

Figure 1.2 (a) Conventional axial images; (b) coronal multiplaner reformat; and (c) 3D volume-rendered CT images of a traumatic axillary artery pseudoaneurysm.

Although there are helpful published criteria for determining the need for cranial and cervical CT scanning following trauma, there are as yet no universally accepted criteria for determining when whole body CT is indicated, and local policies will vary. Most patients are triaged to CT on the basis of mechanism of injury, such as a high-velocity motor vehicle collision, and an initial clinical assessment indicating significant injury, particularly where there is evidence of two or more anatomically remote injuries, for example head injury plus a pelvic fracture or chest injury plus femoral fracture, etc. Whole body CT is also helpful in assessing patients with clinical signs of external trauma in whom the mechanism of injury is unknown, for example a patient found unconscious with bruising, lacerations or an obvious fracture and no available witness statement.

The purpose of this book is to provide a concise and practical guide to the role, performance and interpretation of emergency imaging procedures in patients with major trauma, such as those encountered in road traffic accidents, major disasters such as earthquakes and the victims of civilian or military conflict. The authorship draws on a large number of experienced radiologists and surgeons who manage trauma in their daily practice, both in civilian and military settings. The boundaries of these two seemingly separate spheres are becoming increasingly blurred. Civilian casualties from ballistic trauma and acts of terrorism are frequently encountered in cities throughout the world and lessons learned from medical care in military conflict have relevance in rural, urban and suburban non-military settings.

Figure 1.3 Ultrasound probe positions for a limited focused assessment of sonography in trauma ultrasound examination.

Figure 1.4 Longitudinal ultrasound image of the right upper quadrant demonstrating a small volume of free intraperitoneal fluid (arrows) between the liver (L) and the right kidney (K).

CHAPTER 2
Head and Neck Trauma

Simon Barker¹, Jason H. M. Macdonald¹ and Antonio Belli¹

¹Southampton General Hospital, Southampton, Hampshire, UK

²University of Southampton, Southampton, Hampshire, UK

Head Injury

Trauma is the most common cause of death and permanent disability in the first few decades of life, and head injury is responsible for the majority of this morbidity and mortality. About 1.4 milllion head injuries occur in the United Kingdom each year; 270–313 individuals per 100 000 population are admitted to hospital with this diagnosis per year, and the mortality rate is 6–10 per 100 000 population per year. Death is four times more common in males than females. Road traffic accidents account for a significant proportion of head injury fatalities. Falls represent a higher percentage of injuries at the extremes of life.

Plain radiographs have no primary role in the management of patients with head injury. Computed tomography (CT) is now widely available, fast and accurate in the detection of intracranial haemorrhage. Magnetic resonance scanning is more sensitive for the detection of parenchymal abnormalities, but longer examination times, difficulties in monitoring patients and lower sensitivity for diagnosing fractures have limited its use in primary diagnosis. Boxes 2.1 and 2.2 provide indications for CT in head injury.

Head injuries may be classified as primary or secondary lesions. Primary lesions are a direct result of the traumatic force, which may be penetrating (projectile) or non-penetrating (blunt). In the United Kingdom, blunt injury remains the most common mechanism. Shear-strain deformation of neurones or blood vessels due to rotational acceleration of the head is the commonest mechanism of primary intra-axial injuries. Localized fracture or in-bending of the skull may cause direct injury to the underlying brain.

Secondary lesions develop as a result of primary intracranial lesions or as the neurological effects of systemic injuries. Box 2.3 lists the primary and secondary lesions.

Skull Fracture

Between 25 and 30% of severely injured patients have no identifiable skull fracture. Fractures (Figure 2.1) may be linear (more often associated with extradural and subdural haematomas), depressed (more often accompanied by local brain injury) or involve seperation of a cranial suture. Pneumocephalus may complicate skull-base fractures with a dural tear involving the paranasal sinuses, mastoid ear cells or middle ear.

Figure 2.1 CT scan showing comminuted fracture of right skull vault.

Extradural Haematoma

Laceration of the middle meningeal artery by a fracture is the usual cause of extradural haematoma (Figure 2.2). This is a relatively uncommon injury, but accounts for 10% of fatal head injuries. The temporoparietal region is the most common site. The haematomas are lentiform in shape, and on CT scanning two-thirds are hyperdense and one-third mixed density. Injury to a dural venous sinus by a fracture of the occipital, parietal or sphenoid bone is a much less common cause of extradural haematoma.

Subdural Haematoma

Stretching and tearing of bridging cortical veins as they cross the subdural space is the usual cause of subdural haematoma (Figures 2.3 to 2.6). The arachnoid may also be torn, leading to a mixture of blood and cerebrospinal fluid in the subdural space. Subdural haematoma is seen in up to 30% of fatal head injuries. Acute subdural haematomas are crescentic in shape, and on CT, 60% are hyperdense and 40% mixed density. A subacute subdural haematoma will become isodense to cortex within a few days to weeks of the trauma. Chronic subdural haematomas are often loculated and have a lentiform or crescentic shape. They are predominantly hypodense on CT but may contain areas of fresh haemorrhage.

Traumatic Subarachnoid Haemorrhage

Subarachnoid haemorrhage (Figure 2.7) is seen scattered in superficial sulci and cerebrospinal fluid cisterns in most moderate to severe head injuries.

Figure 2.2 CT scan showing acute extradural haematoma over right temporal lobe. Note the lentiform shape.

Figure 2.3 (a) Axial CT scan showing acute subdural haematoma over right cerebral convexity with midline shift of the brain to the left; (b) coronal reformat demonstrates the full extent of the haematoma and crescentic shape.

Figure 2.4 CT scan shows subacute subdural haematoma over the right cerebral hemisphere is of similar density to the cortex. Cortical sulci and the right lateral ventricle are effaced.

Figure 2.5 CT scan shows layering has occurred in this chronic subdural haematoma.

Diffuse Axonal Injury

Sudden deceleration and rotational forces on the brain cause axonal shearing injuries, which may be accompanied by laceration of adjacent capillaries. Diffuse axonal injury (DAI) (Figures 2.8 and 2.9) occurs most frequently at the grey/white matter interface, particularly in the fronto-temporal region. Lesions are also seen in the posterior corpus callosum. More severe injury involves the basal ganglia, thalamus and dorsolateral midbrain. As 80% of axonal shearing injuries are non-haemorrhagic, a CT scan is often normal. Haemorrhagic shearing injuries are seen as multiple small hyperdense foci. DAI is typically associated with immediate loss of consciousness at the time of injury.

Cortical Contusions

Figure 2.10