Luca saba warren m rozen alberto alonso burgos diego ribuffo imaging for plastic surgery CRC, taylor and francis (2014)

Author(s): Luca Saba; Warren M Rozen; Alberto AlonsoBurgos; Diego Ribuffo Publisher: CRC, Taylor and Francis, Year: 2014 ISBN: 9781466551121,1466551127 Author(s): Luca Saba; Warren M Rozen; Alberto AlonsoBurgos; Diego Ribuffo Publisher: CRC, Taylor and Francis, Year: 2014 ISBN: 9781466551121,1466551127Author(s): Luca Saba; Warren M Rozen; Alberto AlonsoBurgos; Diego Ribuffo Publisher: CRC, Taylor and Francis, Year: 2014 ISBN: 9781466551121,1466551127Author(s): Luca Saba; Warren M Rozen; Alberto AlonsoBurgos; Diego Ribuffo Publisher: CRC, Taylor and Francis, Year: 2014 ISBN: 9781466551121,1466551127Author(s): Luca Saba; Warren M Rozen; Alberto AlonsoBurgos; Diego Ribuffo Publisher: CRC, Taylor and Francis, Year: 2014 ISBN: 9781466551121,1466551127 Author(s): Luca Saba; Warren M Rozen; Alberto AlonsoBurgos; Diego Ribuffo Publisher: CRC, Taylor and Francis, Year: 2014 ISBN: 9781466551121,1466551127

IMAGING

for PLASTIC SURGERY

Boca Raton London New York CRC Press is an imprint of the

Taylor & Francis Group, an informa business

IMAGING

for PLASTIC SURGERY

Edited by Luca Saba Warren M Rozen Alberto Alonso-Burgos

Diego Ribuffo

rectify in any future reprint.

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Luca Saba dedicates this book to his parents, Giovanni Saba and Raffaela Polla, for their love.

Diego Ribuffo dedicates this book to his wife, Stella, and to his wonderful girls, Chiara and Lavinia, for their continuous support during the years in Cagliari.

Warren M Rozen dedicates this book and the time that has gone into it to his wife, Genia, and daughters, Rebecca and Hayley, to whom he will repay that time in full.

Alberto Alonso-Burgos dedicates this book to the real engine of his life, his wife Arantxa and sons Pilar and Miguel and to the memory of his father, José.

Contents

Foreword xi

Preface xiii

Acknowledgements xv

Editors xvii

Contributors xix

Chapter 1 Computed Tomography 1

Michele Anzidei, Federica Ciolina, Fulvio Zaccagna, Alessandro Napoli, and Carlo Catalano Chapter 2 MRI Physics Principles 15

Marta Tomás Mallebrera and Ángeles Franco López Chapter 3 Diagnostic Ultrasound 21

Alberto Benito, David Cano, Mariana Elorz, and Pedro Slon Chapter 4 Nuclear Medicine 31

Alessandra Serra and Mario Piga Chapter 5 Mammography 45

Luis Pina Insauti, Jon Etxano Cantera, Pedro Slon, and Arlette Elizalde Chapter 6 PET-CT in Oncology 71

Anna Margherita Maffione, Sotirios Chondrogiannis, Adriano Marcolongo, and Domenico Rubello Chapter 7 Sentinel Node Biopsy: An Evolution of the Science and Surgical Principles 89

Ramin Shayan, Hayley Reynolds, Cara Michelle Le Roux, and Tara Karnezis Chapter 8 Free Flap Revascularisation Process 103

Emanuele Cigna, Federico Lo Torto, Alessandro Napoli, Jiří Veselý, and Diego Ribuffo Chapter 9 Application of Virtual 3D Plastic Surgery 117

Alberto Alonso-Burgos, Vachara Niumsawatt, and Warren M Rozen Chapter 10 Digital Thermographic Photography for Preoperative Perforator Mapping 129

Vachara Niumsawatt, Warren M Rozen, and Iain S Whitaker

Chapter 14 Imaging and Surgical Principles for Maxillary Reconstruction 233

Riccardo Cipriani, Rossella Sgarzani, Luca Negosanti, Achille Tarsitano, Claudio Marchetti, and Emilia Pascali

Chapter 15 Imaging for Jaw Reconstruction 277

Wei F Chen, Steven Lo, Anuja K Antony, and Fu Chan Wei

Chapter 16 Imaging in Surgical Strategies for Facial Reconstruction 293

Francesco Stagno d’Alcontres, Gabriele Delia, Flavia Lupo, Marcello Longo, Francesca Granata, and Philippe Pelissier

Chapter 17 Imaging and Surgical Strategies for Cutaneous Neoplasm of the Scalp 313

Luca Andrea Dessy, Matteo Atzeni, Andrea Conversi, Luca Saba, Manfredi Greco, and Diego Ribuffo

Chapter 18 Surgical Strategies and Imaging for Regional Flaps in the Head and Neck 327

Gary Xia Vern Tan, Warren M Rozen, Vachara Niumsawatt, Alberto Alonso-Burgos, and Edmund W Ek

Chapter 19 Imaging for Recipient Vessels of the Head and Neck for Microvascular

Transplantation 339

Gary Xia Vern Tan, Warren M Rozen, Vachara Niumsawatt, Alberto Alonso-Burgos, and Edmund W Ek

Chapter 20 Imaging and Surgical Principles for TRAM (pTRAM) Flap 351

Diego Ribuffo, Matteo Atzeni, Maristella Guerra, and Luca Saba

Chapter 21 Angio-CT Imaging of Deep Inferior Epigastric Artery and Deep Superior

Epigastric Artery Perforators 365

Vachara Niumsawatt, Warren M Rozen, Mark W Ashton, Iain S Whitaker, Emilio García-Tutor, and Alberto Alonso-Burgos

Chapter 23 Surgical Principles of Deep Inferior Epigastric Artery and Deep Superior

Epigastric Artery Perforator Flap 397

Vachara Niumsawatt, Mark W Ashton, Warren M Rozen, and Iain S Whitaker

Chapter 24 Imaging and Surgical Principles of the Superficial Inferior Epigastric

Chapter 26 Surgical Principles and Imaging of Breast Implants and Their Follow-Up 449

Luca Andrea Dessy, Nefer Fallico, Gloria Pasqua Fanelli, Carlo De Masi, Luca Saba, Diego Ribuffo, and Nicolò Scuderi

Chapter 27 Lymphatic Imaging of the Breast: Evolving Technologies and the Future 465

Jaume Masia, Gemma Pons, Maria Luisa Nardulli, Juan Angel Clavero, Xavier Alomar, and Joan Duch

Chapter 28 Breast Imaging for Aesthetic and Reconstructive Plastic Surgery 485

Jeremy Nickfarjam, Oren Tepper, and Nolan Karp

Chapter 29 Imaging for Incisional Median Abdominal Wall Hernias 497

Pietro Giorgio Calò, Giuseppe Pisano, Luca Saba, Matteo Atzeni, Fabio Medas, and Angelo Nicolosi

Chapter 30 Imaging and Surgical Principles of Perforator Flaps of the Trunk 513

Michel Saint-Cyr

Chapter 31 Phalloplasty in Female-to-Male Sex Reassignment Surgery 535

Zdeněk Dvořák and Jiří Veselý

Chapter 32 Imaging and Surgical Principles of the Gluteal Arteries

and Perforator Flaps 549

Julie Vasile, Maria M Lotempio, and Robert J Allen

Chapter 36 Surgical Principles of Deep Circumflex Iliac Artery 597

Warren M Rozen, Mark W Ashton, Vachara Niumsawatt, Alberto Alonso-Burgos, Iain S Whitaker, and Jeannette W Ting

Chapter 37 Imaging and Surgical Principles of the Propeller and Perforator Flaps

of the Lower Limb 609

Emanuele Cigna, Michele Maruccia, Alessandro Napoli, Federico Lo Torto, Paola Parisi, and Diego Ribuffo

Chapter 38 Lymphoscintigraphy for Extremities’ Oedemas and for Sentinel Lymph Node

Mapping in Cutaneous Melanomas of the Torso 643

Giuliano Mariani, Paola A Erba, Gianpiero Manca, Luisa Locantore, Federica Orsini, Sara Mazzarri, Valerio Duce, Manuel Tredici, and Elisa Tardelli

Chapter 39 Nuclear Medicine as an Aid to Minimally Invasive Surgery, with Emphasis

on Hybrid SPECT/CT Imaging 673

Federica Orsini, Alessandra Serra, Mario Piga, and Giuliano Mariani

Chapter 40 Preoperative Imaging for Reconstruction of the Lower Extremities 709

Hidehiko Yoshimatsu and Takumi Yamamoto

Chapter 41 Imaging and Surgical Principles in Hand Surgery 717

Giorgio Pajardi and Andrea Ghezzi

Chapter 42 Imaging and Surgical Principles of Osteomyelitis and Pressure Ulcers 793

Bruno Carlesimo, Marco Ruggiero, Federico Lo Torto, and Marco Marcasciano

Chapter 43 Image Guided 3D Printing and Haptic Modelling in Plastic Surgery 819

Michael P Chae, David J Hunter-Smith, and Warren M Rozen

Index 831

Foreword

It is not strange that a few years after the discovery by Röntgen of the x-rays, several researchers

were trying to depict, by using the new and revolutionary light, the anatomy of the vessels The

morphology of arteries and veins was some kind of mystery, only available by anatomical tions and by casts obtained after its extraction Once liquid intravascular contrasts were developed, many groups worldwide produced, by using rudimentary but at the same time very imaginative techniques, new images of the flow within the vessel lumen

dissec-Since that time, this effort has never decreased, and there is still a maintained interest in izing the imaging of the vessel walls and the study of all the intrinsic peculiarities of the vascular flow Sectional imaging methods have replaced the conventional angiographic techniques in which

actual-a cactual-atheter is plactual-aced within the lumen by percutactual-aneous actual-approactual-ach Such clactual-assic procedures actual-are now used exclusively for therapeutic purposes like angioplasty or embolization

The new methods for vascular diagnosis must include several concepts such as a meticulous analysis of its morphology, branching, and relation with other structures Also, a careful evaluation

of the vessel wall layers with precise knowledge of its characteristics, thickness, pathology, and also its flow, in terms of amount, velocity, or direction of the main stream, which may have great influ-ence on the performance of any endovascular procedure as well as on the consequences that any endovascular therapy may have in the future must be done

Vascular diagnosis should then contemplate not only morphology but also function and should

be associated with the study of biomarkers that may allow the early detection and subsequent tification of the consequences that any flow change (e.g., insufficiency or turbulence) may have in the targeted viscera or organ

quan-Imaging techniques allow, at this moment, the evaluation of the morphology of the vessels in such a way that many outstanding anatomists could never imagine just before Röntgen introduced

the light to see in depth This book is an outstanding example.

José I Bilbao, MD

Head of Vascular and Interventional Unit

University of Navarra Clinic

Pamplona, Spain

Over the past years, we have seen continuous and increasingly rapid development of accessible imaging techniques Imaging procedures allow integrating the information strictly anatomical, with submillimeter resolution, with that of a functional nature related to molecular imaging All detailed derived information allows plastic surgeons to have precise preoperative data strictly related to the real clinical status of the patient This book comes at the right time. The accurate presentation, to the interested reader, of the most recent and relevant imaging methodologies, from innovative ultra-sound procedures to CT and from MRI to numerous and sophisticated surveys of nuclear medicine, helps to make valuable contributions of knowledge to a competent user who is here the modern plastic surgeon Its success is largely due to Dr Saba’s and coeditors’ broad experience and enthusi-asm and their special talent of involving skilled colleagues in relation to their specific competence

Mario Piga, MD

Professor of Nuclear Medicine

and Chief of Radiology and Nuclear Medicine Department

University Hospital, Cagliari, Italy

Nicolò Scuderi, MD

Professor of Plastic Surgery

and Chief of Plastic Surgery Unit Sapienza University Hospital, Rome, Italy

Preface

Over the past five years, preoperative imaging has become increasingly adopted for preoperative planning in plastic surgery, with particular applications in perforator flap surgery and 3-D facial reconstruction at the forefront Accurate preoperative analysis can reduce the length of operations and maximise surgical design and dissection techniques This is the first collection to be published dedicated to the application of advanced imaging technologies in plastic and reconstructive surgery.New imaging modalities have advanced to previously inconceived heights, with high-resolution, 3-D analysis of vascular anatomy and perfusion now attainable Computed tomography (CT) and magnetic resonance imaging (MRI) have recently emerged as outstanding non-invasive techniques for the study of the vascular and non-vascular systems In particular, CT angiography has probably

now imposed itself as the state-of-the-art technique to explore the vascular system, with evolving

MR angiography (MRA) sequences and greater magnetic fields (3 T or more) with the potential to become a matching modality in the future

This project arises from the cooperation and friendship between the groups of radiology and plastic surgery of the European and Australian universities that shared an extensive experience in these topics in the last 10 years The authors are world-renowned scientists who have dedicated most of their work to this exciting field This book is the concrete example of how multidisciplinary cooperation and friendship can lead to excellent results

The scientific purpose of this book is to comprehensively present all of the imaging techniques, potentialities, and present and future applications as applied to plastic and reconstructive surgery

Luca Saba Warren M Rozen Alberto Alonso Burgos

Diego Ribuffo

Acknowledgements

It is not possible to overstate the gratitude to the many individuals who helped to produce this book

In particular, the editors thank Matteo Atzeni for his help

Dr Luca Saba acknowledges the patience and understanding displayed by Tiziana throughout his work Without her continuous encouragement, this book would not have been completed

Diego Ribuffo thanks all the contributors from his home university for their enthusiasm and collaboration

Warren M Rozen thanks the contributors and coauthors with whom he has collaborated in this volume and the ongoing institutional support for his research interests and advances

Alberto Alonso-Burgos thanks all the colleges involved in this book for their enthusiasm and laboration and the support from the University of Navarra Clinic then and the University Hospital Fundación Jiménez Díaz now

col-The editors have received considerable support and cooperation from individuals at CRC Press/ Taylor & Francis Group, particularly Michael Slaughter, Jessica Vakili, Joette Lynch, and Michele Smith, and from Dennis Troutman at diacriTech, each of whom helped to minimize the obstacles editors encountered

Editors

Luca Saba received his MD from the University of Cagliari,

Italy, in 2002 Today he works in the AOU (Azienda Ospedaliero Universitaria) of Cagliari Dr Saba’s research focuses on multi-detector-row computed tomography, magnetic resonance, ultra-sound, neuroradiology, and diagnostics in vascular sciences His works as lead author include more than 130 high-impact-

factor, peer-reviewed journals such as the American Journal of

Neuroradiology, Atherosclerosis, European Radiology, European Journal of Radiology, Acta Radiologica, CardioVascular  and Interventional Radiology, Journal of Computer Assisted Tomography, American Journal of Roentgenology, Neuro radiology,  Clinical Radiology, Journal of Cardiovascular Surgery, Cerebrovascular Diseases, Brain Pathology, and Medical Physics

He is a well-known speaker and has given more than 45 speeches at the national and tional levels

interna-Dr Saba has won 15 scientific and extracurricular awards during his career He has presented more than 450 papers and posters in national and international congresses (RSNA, ESGAR, ECR, ISR, AOCR, AINR, JRS, SIRM, AINR) He has written 18 book chapters and is editor of 7 books

in the fields of computed tomography, cardiovascular, plastic surgery, gynaecological imaging, and neurodegenerative imaging

He is member of the Italian Society of Radiology (SIRM), the European Society of Radiology (ESR), the Radiological Society of North America (RSNA), the American Roentgen Ray Society (ARRS), the and European Society of Neuroradiology (ESNR) and serves as reviewer of more 30 scientific journals

Warren M Rozen is a consultant plastic and reconstructive

sur-geon in Melbourne, Australia He combines clinical practice in plastic and reconstructive surgery with translational research at Monash University and James Cook University, following comple-tion of postgraduate studies in surgical anatomy through an MD and

a PhD He has contributed to more than 400 publications, has given more than 100 national and international research presentations, and is on the editorial board of 9 international journals including the

Annals of Plastic Surgery and Microsurgery His academic interests include reconstructive flap design and preoperative flap planning

Alberto Alonso-Burgos MD, PhD, is a consultant radiologist in

the Vascular and Interventional Radiology Unit at the University Hospital Fundación Jiménez Díaz (Madrid, Spain) He completed all his medical training (MD, 2003; PhD, 2009; and diagnostic radiology residency, 2008) at the University of Navarra and Clinic University of Navarra (Pamplona, Spain) His main interest and research have been focused on CT and MRI angiography for recon-structive surgery and preoperative 3D planning as well as oncologic interventional radiology He has published more than 25 papers and

10 chapters and has been the editor of textbooks, including the first general imaging text for reconstructive plastic surgery

versity, where he currently serves as associate professor of plastic surgery in the Department of Surgery, Pietro Valdoni at Sapienza University of Rome.

Contributors

Robert J Allen

The Center for the Advancement of Breast

Reconstruction at New York

New York Eye and Ear Infirmary

and

New York University Medical Center

New York

and

Medical University of South Carolina

Charleston, South Carolina

University Hospital Fundación Jiménez Díaz

Autonomous University of Madrid

Royal Melbourne Hospital

Parkville, Victoria, Australia

Matteo Atzeni

Section of Plastic SurgeryDepartment of SurgeryCagliari University HospitalCagliari, Italy

Alberto Benito

Department of RadiologyClínica Universidad de NavarraPamplona, Spain

Barbara Cagli

Division of Plastic and Reconstructive SurgeryCampus Bio-Medico of Rome UniversityRome, Italy

Pietro Giorgio Calò

Department of Surgical SciencesUniversity of Cagliari

Cagliari, Italy

David Cano

Department of RadiologyClínica Universidad de NavarraPamplona, Spain

Jon Etxano Cantera

Department of RadiologyClínica Universidad de NavarraPamplona, Spain

University of Iowa Hospitals and Clinics

Iowa City, Iowa

Sotirios Chondrogiannis

PET Unit

Department of Nuclear Medicine

Santa Maria della Misericordia Hospital

Division of Plastic Surgery

S Orsola-Malpighi University Hospital

Bologna, Italy

Plastic Surgery UnitPoliclinico “G Martino” University HospitalMessina, Italy

Gabriele Delia

Plastic Surgery UnitPoliclinico “G Martino” University HospitalMessina, Italy

Carlo De Masi

Department of RadiologyS.M Goretti HospitalLatina, Italy

Luca Andrea Dessy

Unit of Plastic SurgeryDepartment of SurgerySapienza University of RomeRome, Italy

Valerio Duce

Regional Center of Nuclear MedicineDepartment of Translational Research and Advanced Technologies in Medicine and Surgery

University of PisaPisa, Italy

Joan Duch

Department of Nuclear MedicineSanta Creu i Sant Pau HospitalAutonomous University of Barcelona (UAB)Barcelona, Spain

Ahmet Duymaz

Department of Plastic and Reconstructive Surgery

School of MedicineAkdeniz UniversityAntalya, Turkey

Contributors

Medical Faculty of Masaryk University Brno

Clinic of Plastic and Aesthetic Surgery

St Anna’s University Hospital

Brno, Czech Republic

Regional Center of Nuclear Medicine

Department of Translational Research and

Advanced Technologies in Medicine

and Surgery

University of Pisa

Pisa, Italy

Piergiorgio Falappa

Institute of Rome Italy

Bambino Gesù Children’s Hospital—I.R.C.C.S

Plastic and Reconstructive Surgery Department

Guadalajara General Hospital

Guadalajara, Spain

Andrea Ghezzi

Director of Hand Surgery Department

St Joseph Hospital MultiMedica Groupand

Plastic Surgery SchoolUniversity of MilanMilan, Italy

Francesca Granata

Neuroradiology UnitPoliclinico “G Martino” University HospitalMessina, Italy

Manfredi Greco

Unit of Plastic and Reconstructive SurgeryDepartment of Surgery

University of CatanzaroCatanzaro, Italy

Maristella Guerra

Unit of Plastic SurgerySan Gallicano-IFO HospitalRome, Italy

Luis Pina Insauti

Department of RadiologyClínica Universidad de NavarraPamplona, Spain

Kamil Karaali

Department RadiologySchool of MedicineAkdeniz UniversityAntalya, Turkey

Tara Karnezis

The Taylor LabDepartment of Anatomy and NeurosciencesUniversity of Melbourne

Parkville, Victoria, Australia

Nolan Karp

Department of Plastic SurgeryNew York University School of MedicineNew York, New York

Cara Michelle Le Roux

The Taylor LabDepartment of Anatomy and NeurosciencesUniversity of Melbourne

Parkville, Victoria, Australia

Marcello Longo

Neuroradiology Unit

Policlinico “G Martino” University Hospital

Messina, Italy

Ángeles Franco López

Cardiac Imaging Unit

Department of Radiology

University Hospital Fundación Jiménez Díaz

Madrid, Spain

Maria M Lotempio

Center for the Advancement of Breast

Reconstruction at New York

New York Eye and Ear Infirmary

New York, New York

and

Medical University of South Carolina

Charleston, South Carolina

Plastic Surgery Unit

Policlinico “G Martino” University Hospital

Messina, Italy

Anna Margherita Maffione

PET Unit

Department of Nuclear Medicine

Santa Maria della Misericordia Hospital

Rovigo, Italy

Regional Center of Nuclear MedicineDepartment of Translational Research and Advanced Technologies in Medicine and Surgery

University of PisaPisa, Italy

University of PisaPisa, Italy

Michele Maruccia

Unit of Plastic SurgeryDepartment of SurgerySapienza University of RomeRome, Italy

Jaume Masia

Department of Plastic SurgerySanta Creu i Sant Pau HospitalAutonomous University of Barcelona (UAB)Barcelona, Spain

Contributors

Sara Mazzarri

Regional Center of Nuclear Medicine

Department of Translational Research and

Advanced Technologies in Medicine and

Unit of Plastic and Reconstructive Surgery

Department of Surgical, Oncological and

Maria Luisa Nardulli

Department of Plastic Surgery

Santa Creu i Sant Pau Hospital

Autonomous University of Barcelona (UAB)

Barcelona, Spain

Luca Negosanti

Division of Plastic Surgery

S Orsola-Malpighi University Hospital

Bologna, Italy

Jeremy Nickfarjam

Division of Plastic Surgery

Albert Einstein School of Medicine

Bronx, New York

Monash Medical Centre

Clayton, Victoria, Australia

Federica Orsini

Regional Center of Nuclear MedicineDepartment of Translational Research and Advanced Technologies in Medicine and Surgery

University of PisaPisa, Italy

Ömer Özkan

Department of Plastic and Reconstructive Surgery

School of MedicineAkdeniz UniversityAntalya, Turkey

Özlenen Özkan

Department of Plastic and Reconstructive Surgery

School of MedicineAkdeniz UniversityAntalya, Turkey

Giorgio Pajardi

Director of Hand Surgery Department

St Joseph Hospital MultiMedica Groupand

Plastic Surgery SchoolUniversity of MilanMilan, Italy

Tiziano Pallara

Division of Plastic and Reconstructive SurgeryCampus Bio-Medico of Rome UniversityRome, Italy

Paola Parisi

Department of SurgeryMonash Plastic Surgery Research UnitMonash University

Clayton, Victoria, Australia

Department of Plastic Surgery

Santa Creu i Sant Pau Hospital

Autonomous University of Barcelona (UAB)

Barcelona, Spain

Hayley Reynolds

The Taylor Lab

Department of Anatomy and Neurosciences

Department of Nuclear Medicine

Santa Maria della Misericordia Hospital

Rovigo, Italy

University of CagliariCagliari, Italy

Contributors

Rossella Sgarzani

Division of Plastic Surgery

S Orsola-Malpighi University Hospital

Bologna, Italy

Ramin Shayan

The Taylor Lab

Department of Anatomy and Neurosciences

Clayton, Victoria, Australia

Gary Xia Vern Tan

Department of Surgery

Monash Medical Centre

Clayton, Victoria, Australia

Elisa Tardelli

Regional Center of Nuclear Medicine

Department of Translational Research and

Advanced Technologies in Medicine

Division of Plastic Surgery

Albert Einstein School of Medicine

Bronx, New York

Jeannette W Ting

Department of Surgery

Monash Medical Centre

Clayton, Victoria, Australia

Manuel Tredici

Regional Center of Nuclear MedicineDepartment of Translational Research and Advanced Technologies in Medicine and Surgery

University of PisaPisa, Italy

Donata Maria Antonia Assunta Vaccaro

Division of RadiologyCampus Bio-Medico of Rome UniversityRome, Italy

Julie Vasile

Northern Westchester Hospital

Mt Kisco, New York

Morriston HospitalSwansea, Wales

Michele Anzidei, Federica Ciolina, Fulvio Zaccagna,

Alessandro Napoli, and Carlo Catalano

In the last few years, the use of computed tomography angiography (CTA) in the clinical workup of patients with known or suspected cardiovascular disease has grown rapidly With the introduction of spiral CT scanning in the 1990s and the transition to multidetector row technology, and the conse-quent reduction in acquisition times, CTA has developed so fast that in a few years it has become an easy-to-perform and well-standardised technique At present, CTA plays a major role in the diagno-sis and follow-up of cardiovascular disease, including coronary pathologies, and can be considered

as a robust alternative to invasive catheter angiography under different circumstances (e.g diagnosis

of complex vascular and skeletal anomalies, traumatic injuries and their preoperative evaluation) In parallel to these applications, CTA was recently used for vascular mapping in patients undergoing plastic surgery interventions

1.1 EXAMINATION TECHNIQUE

Computed tomography (CT) is a tomographic technique that uses x-ray to produce images One

or, more recently, two x-ray sources rotate around the patient, and the x-ray beams produced by these sources are detected by a panel of detectors on the other side of the gantry After the acquisi-tion of x-ray attenuation data, a mathematical image reconstruction (inverse Radon transformation) approach is used to calculate the local attenuation of each point of acquisition volume, and hence,

CT images were produced in greyscale to represent the attenuation data

The introduction of helical acquisition yields a reduction in acquisition time as mentioned earlier, but it also permits performing a volumetric acquisition that is mandatory to obtain CTA images of adequate quality Moreover, the use of contrast medium (CM) and proper timing is mandatory to obtain a good-quality CTA acquisition

CONTENTS

1.1 Examination Technique 11.2 Volumetric Acquisition and Quality Assessment of CTA 21.3 Acquisition Parameters 21.4 Reconstruction Parameters 31.5 Contrast Medium Administration 41.6 Contraindications to the CM Use in CTA Examinations 51.7 CM Administration Strategy 61.8 CM Volume and Iodine Delivery Rate 61.9 Saline Flush 81.10 Patients’ Characteristics and Vascular Enhancement 81.11 Timing of CTA Acquisition 91.12 Radiation Dose Considerations 101.13 Artefacts 101.14 CT Applications in Plastic Surgery 11

layer thickness Sometimes, the use of maximum spatial resolution is not allowed due to to-noise ratio (which is defined as ‘a numerical size which correlates the power of the useful signal with the noise in any system of acquisition, processing or transmission of the information’), so acquisition parameters need to be optimised to obtain the best compromise between spatial and temporal resolution and image quality (represented by the SNR) In particular, with the new gen-eration multidetector CT (MDCT) scans, above 64 slices, it is now possible to acquire slices under

signal-1 mm, but this increase in spatial resolution induces a reduction of the SNR

Considering how important it is to obtain adequate quality images, handling both acquisition and reconstruction parameters is essential

The most important acquisition parameters are the number of active detectors and detector limation, pitch, tube load, and tube voltage Meanwhile, the most important reconstruction param-eters are section thickness, reconstruction increment or interval, field of view, reconstruction matrix size, and reconstruction filter or algorithm

col-1.3 ACQUISITION PARAMETERS

The number of active detectors is the number of sections that are acquired simultaneously, and

it could be as high as the detector rows of the CT scan but could also be less than the maximum achievable

Detector collimation is determined by the opening degree of detectors, and it varies the tude of the photon beam used to detect the attenuation profiles of the object under examination.Pitch factor is the relation between the table feed and the total width of the acquired volume Pitch factor is obtained by the following relation: P = TF/(N × C), where TF is the table feed, N is the detector number, and C is the beam collimation

4

FIGURE 1.1 Volumetric spiral scan: the highest detectors number, the greatest volume acquired.

Computed Tomography

Tube load (mAs) determines the number of photons produced by the x-ray tube and is tional to the radiation dose Tube voltage (kVp) is the potential difference between the two extremi-ties of the x-ray tube, and it determines the energy of the x-ray beam These two parameters are the most important to limit radiation exposure In fact, the dose increased linearly with an increase of mAs and with an exponential relationship with an increase of kVp It is mandatory to know that with

propor-a decrepropor-ase of the kVp, the photon energy lessens propor-and the tissue propor-attenupropor-ation (CM included) increpropor-ases, with a consequent greater contrast resolution (Figure 1.2) With this rule, in cases in which a lesser volume of CM is required (e.g in patients with cardiac or renal failure or in paediatric patients), using a lower kVp value could balance the lower enhancement due to the lower CM volume and achieve a good contrast resolution

1.4 RECONSTRUCTION PARAMETERS

Section thickness is the width of the contiguous layer in the final images, and it refers to the images obtained in all the three reconstruction planes It can be equal to or greater than the value of the collimation, but not less than it Using a section thickness greater than collimation, we can have a lower noise in the final data set

Reconstruction interval represents the overlap between two contiguous layers It could be higher, equal to, or lesser than the layer thickness, resulting, respectively, in layers which are spaced, adja-cent, or overlapped

Field of view (FoV) represents the size of the planar images on the transverse plane Using a small FoV generates higher-resolution images but with a higher noise (Figures 1.3 and 1.4)

Reconstruction matrix is the number of pixels that constitute the image It is normally of fixed size (512 × 512), but new CT scanners can have a bigger matrix to increase spatial resolution.Reconstruction algorithms (or convolution filters) are used to reconstruct images from the raw data Information on the attenuation profiles of the object under examination is reworked by means

of mathematical algorithms which apply appropriate correction functions of the data before the production of the final image By using this, we can obtain the highest influence on the quality of the planar reconstructed image (Figure 1.5)

The use of high-definition filters (sharp) increases the spatial resolution, but also the image noise; the use of soft filters (smooth) reduces the definition, but also the noise level

100 mAs – 120 kVp

130 mAs – 120 kVp

FIGURE 1.2 Study of the peripheral system in two patients with a similar body mass, evaluated both at

120 kVp but with 100 mAs and 130 mAs, respectively The use of a greater amount of mAs produces an image with less noise and a greater contrast resolution.

1.5 CONTRAST MEDIUM ADMINISTRATION

The use of CM in CTA is mandatory to achieve opacification of vascular structure The CMs used in CT are water-soluble derivatives of symmetrically iodinated benzene (triiodobenzene) with a high atomic number able to determine x-ray attenuation The goal of CM administration is to achieve the maximum achievable opacification of vascular structure, and as it seems obvious that for the same administration (total dose of CM and infusion speed expressed in mL/s) and scanning parameters (mAs and kVp), the higher the iodine concentration is (expressed in mgI/mL), the greater will be the enhancement, hence, it is mandatory to know the principle of CM administration well to adapt it to the patient and the CT scanner

At present, different CMs are available on the market that have different iodine concentrations and other chemical–physical characteristics But they are used only for their ability to determine the x-ray attenuation, and hence, all pharmacological effects are generally undesired Ionic CMs are no longer available on the market due to adverse effects, and hence, all the CMs available now are non-ionic

FIGURE 1.3 Particular of the abdomen reconstructed using a slice thickness of 1 mm (a) and 3 mm (b).

FoV 125 mm (a)

(b)

FIGURE 1.4 Patient with aneurism of the popliteal artery of the left inferior limb: FoV reconstruction of

350 mm (including both legs) (a) and limited to one leg (b).

Computed Tomography

These contrast agents are molecules with an interstitial-type bio-distribution; once administered venously, they undergo an initial phase of vascular distribution, followed by an interstitial distribution

intra-1.6 CONTRAINDICATIONS TO THE CM USE IN CTA EXAMINATIONS

Contraindications to the use of iodinated contrast agents include the following:

• History of previous allergic events related to CM or atopy In these cases, an appropriate prophylaxis must be applied (ESUR guidelines: prednisolone 30 mg 12 h and 2 h before the examination)

• Renal failure (GFR <30 mL/min): It requires both proper hydration (before and after the examination) and reduction of the total amount of administered contrast agent In the cases

of advanced renal failure, a dialysis treatment will be necessary

• Heart failure: The danger is related to a cardiovascular failure due to a circulatory overload

In this patient, it is mandatory to minimise the total amount of contrast agent administered

• Pregnancy and nursing: Although there is no definitive information, it is possible that a portion of the CM can be temporarily secreted in mother’s milk Breastfeeding should be discontinued for approximately 24 h after the examination

• Multiple myeloma and Waldenström’s macroglobulinemia

• Patients treated with nephrotoxic drugs (NSAIDs or especially metformin): Therapy should

be discontinued at least 48 h before the examination and should be resumed 48 h after.These contraindications can increase the risk of adverse effects and also the risk of contrast-induced nephropathy (CIN) In particular, CIN is a clinical entity characterised by acute deterioration of renal function that occurs 48–72 h after CM administration in the absence of other possible causes.According to the severity of the clinical manifestations, allergic reactions that may occur follow-ing CM administration can be classified as

• Side effects (nausea, emesis, altered taste, sweating, etc.)

• Mild side effects (itching, hives, coughing, sneezing, etc.)

FIGURE 1.5 Use of different kernel reconstruction to obtain better image quality.

during the entire scan duration, without overlapping opacification of venous vessels (Figure 1.6).However, this constant opacification is already impossible in vivo because CM distribution tends

to be a parabolic curve that is different from patient to patient

Moreover, CM, after the first arterial phase, will distribute into the parenchymal interstitial space (parenchymal enhancement), and a small amount will enter a phase of ‘recycling’ going back to the vascular space In relation to these physiological data, it is therefore possible to consider a single bolus of CM as the set of multiple fractions of volume, subjected to the recirculation phenomena, each of which contribute to a greater and longer-lasting enhancement (‘additive model’, Figure 1.7)

1.8 CM VOLUME AND IODINE DELIVERY RATE

The choice of CM volume is linked to the speed of injection and iodine concentration For CTA, it

is necessary to use high-speed injection rates in order to avoid bolus dilution within the vascular site and to obtain an intense and lasting enhancement through the acquisition time By using high-speed injection rates, the intensity of vascular enhancement will be greater but its duration will be reduced.For CT scanner under 16-channel, the CM was injected for a time equal to the scan time and so the

CM quantity is directly obtained from scan duration and speed of injection In this manner, tion of vascular structure was constant during the entire scan, but sometimes it requires a lot of CM.The last generation MDCT scan with a high number of detectors (64–128–320 MDCT) and the consequent reduction in acquisition time have made this approach obsolete (Figure 1.8)

opacifica-For example, if we consider a carotid artery acquisition with a >16 MDCT scan, the duration of acquisition will be 6 s, and therefore, considering an injection speed of 4 mL/s, the suggested dose

is only 24 mL of CM, too less to achieve a good opacification

Diagnostic window SI

Seconds

Arteries Veins

FIGURE 1.6 In vascular study the perfect diagnostic window is during the arterial peak phase; acquisition

during the venous phase results in parenchimal study.

Computed Tomography

128-CT 64-CT 16-CT 4-CT

30 s 60 s

Scan time HU

FIGURE 1.8 The greatest is the number of detectors the lowest is the scan time and the earliest peak

enhancement.

400 (4 mL/s)

+16 mL +16 mL +16 mL

128 mL +

8 6 4 2 0

1 9 17 25 33 8

6 4 2 0

1 9 17 25 33

300 200 100 0

0 8 16 24 32 40 48 56 64 72

Additive model

80 400

300 200 100 0

0 8 16 24 32 40 48 56 64 72 80

FIGURE 1.7 Continuous administration of 128 mL of contrast agent may be considered as a subsequent

injection of multiple little bolus of 16 mL The effective vascular enhancement results in the bell curve of contrast media (Fleischmann et al Eur Radiol 2002; 12: S11–16).

determines a vascular enhancement of greater intensity and duration, but with a slower onset, while

a reduced volume of CM produces faster enhancement but of less intensity and duration So higher volumes of CM could be used for large vascular segments (peripheral circulation, thoracic and abdominal aorta, or whole-body examination), while smaller volumes of CM could be used for smaller regions (neck vessels or coronary circulation)

1.9 SALINE FLUSH

The use of a saline bolus of 40–50 mL injected at a high flow (3.5–4 mL/s, usually 0.5 mL/s higher than the CM considering the different viscosity of the two solutions) immediately after the adminis-tration of CM to flush the venous system could improve the quality of CTA This high-speed bolus helps the progression of the contrast agent avoiding its presence in the venous site, consolidates the

CM bolus, and moreover brings to a reduction the total amount of CM administered

1.10 PATIENTS’ CHARACTERISTICS AND VASCULAR ENHANCEMENT

Vascular opacification is due to many factors, some related to acquisition technique as stated earlier and others due to patients’ characteristics such as cardiac output or body mass

The cardiac ejection fraction directly influences the distribution speed of the contrast agent through the vascular site, with a particular effect on the arterial concentration during the first pass

In patients with a history of heart failure, the circulation speed of the contrast agent is reduced and its arrival in the target vascular territories is delayed In the same way also the effect of the venous

Computed Tomography

washout is delayed by the reduced cardiac function The final result of these phenomena is therefore

a delayed peak of enhancement but more intense than the one that we have in the case of a normal cardiac function; the effect is more apparent to progressively reduced ejection fraction

Patients’ body mass influences the distribution volume of CM as well as its pharmacodynamics and pharmacokinetics (Figure 1.9) So it is necessary to adjust the amount of CM in relation to body weight In subjects with a high body mass, the CM is mainly diluted in the blood, resulting in a lower iodine concentration and a lower enhancement Correction of the CM volume for the body mass is nec-essary for subjects with a weight less than 60 kg or greater than 90 kg (reducing or increasing, respec-tively, 20% of the standard volume of CM and varying the same percentage of the administration rate)

1.11 TIMING OF CTA ACQUISITION

The right scan timing (or scan synchronisation) is mandatory to obtain a good-quality CTA tion The following are the techniques used to synchronise CM administration and CTA acquisition:

examina-• Fixed delay (now considered obsolete): It is based on the use of fixed delay between CM administration and the beginning of the scan

• Test bolus: It is based on the administration of a small amount of CM (15–20 mL) used

to determine the time needed to reach peak enhancement to set delay of CTA acquisition (Figure 1.10) It is a technically valid method but is now replaced by the more simple and rapid technique of bolus tracking

• Bolus tracking: It is based on a real-time monitoring of the enhancement in a vessel in which attenuation is continuously measured (Figure 1.11) When attenuation reaches a selected threshold value (expressed in HU), CTA scan will start automatically after a delay that is settled as lower as possible (usually 6–8 s) Threshold attenuation value (expressed

in HU) is variable according to vascular region (70–90 HU for the carotid arteries, 150–200 HU for the aorta, and 50–60 HU for pulmonary arteries) and to the speed of acquisition (with faster scanners it should be set at higher threshold values in order to avoid the bolus overcome and a subsequent too early inadequate acquisition)

To summarise, among latest CT scans, the bolus tracking technique is the technique of choice; ever, the test bolus could be a good alternative among older-generation CT scans

how-HU

PME

150 0

1.12 RADIATION DOSE CONSIDERATIONS

Radiation dose in CT depends on mAs and kV, layer collimation, and acquisition time The istered radiation dose is measured as CTDIvol, which is the average exposure dose in a given vol-ume, and is expressed in milligray (mGy) CTDIvol is automatically calculated based on the pitch, mAs, kVp, and on some specific scanner parameters

admin-In patients with a mean BMI, the recommended maximum CTDIvol for a CTA examination of the thoracic and abdominal vessels is, respectively, 5–6 mGy and 8–15 mGy In overweight patients,

it is necessary to use higher doses to maintain an acceptable image quality As stated previously, it

is important to remember that the use of low kVp (80–100), in patients with mean BMI, can increase the iodine attenuation Moreover, a variation in acquisition parameters influences both radiation dose and image quality, so it is important to balance dose exposure and quality of the acquired images.Recently, new techniques based on a real-time modulation of the x-ray tube load (mAs) along

the z-axis considering the different body thickness determine an exposure dose reduction up to

20%–30% without a decrease in image quality So if these techniques  of dose modulation are able, their use is strongly suggested

• Contrast agent over-concentration: Typically evident at the brachiocephalic venous trunk

It determines a beam-hardening artefact in the aortic arch and epiaortic vessels It is reduced by a saline flush administered immediately after the CM

• Turbulent and slow flow: It determines a patchy opacification of a vessel caused by low and inhomogeneous CM concentration Typical examples are represented by the patchy effect induced by the flow turbulence in the aneurysmal sacs or by the asymmetrical enhance-ment of the leg distal vessels in patients with a slow circulation time

0

FIGURE 1.11 Bolus tracking.

Computed Tomography

• Calcifications, stent devices, embolic materials, and other metallic implants: Even if the CTA capability to identify the wall calcifications is an undeniable advantage, it may also constitute a limitation of the study because it hinds proper evaluation of vessel lumen due

to ‘blooming artefact’ owing to beam hardening Similar alterations are observed in the presence of metallic materials (implants, stent devices, and embolic agents) The effect of these artefacts can be reduced with the use of high-spatial resolution reconstruction tech-niques and the application of high-definition convolution filters

1.14 CT APPLICATIONS IN PLASTIC SURGERY

In plastic surgery, it is often mandatory to assess vascular and skeletal anatomy before surgical repair of congenital diseases and post-traumatic injuries (Figure 1.12)

Moreover, CTA has a central role in surgical reconstruction in patients that underwent demolitive surgery for tumours, such as breast reconstruction: it is considered safe and reliable in the assessment

of vascular anatomy during perforator flap reconstruction (using the deep inferior epigastric artery, the superficial inferior epigastric artery, or the gluteal arteries), and may prevent the number of post-operative complications It enables flap selection (based on size, location, course, and length), target donor vessel, level and type of anastomosis through the use of multiplanar reformations (MPRs), volume rendering (VR), and maximum intensity projection (MIP) reconstructions in different planes

In addition, the use of dedicated software with a scale grid superimposed on the image may show the relations of the little vessels to other anatomical structures, guiding the surgeon during the intervention and resulting in a decreased mean operating time, a lower rate of complications related

to flap viability, and a significant reduction in donor site morbidity

CT reconstructions frequently used are as follows:

• MPR are two-dimensional reformatted images that are reconstructed secondarily in ent planes (coronal or sagittal) from the stack of axial image data Particular applications

differ-of MPR imaging are the curved-planar reformations (CPR) that are generally needed to depict structures that pass through multiple axial planes of section (e.g vessels)

• MIP images are volume-rendering techniques in which suitable editing methods are used

to define the volume of interest (VOI) Images are generated by projecting the volume of interest into a viewing plane and displaying the maximum CT numbers that are encoun-tered along the direction of the projection (the viewing angle) MIP are generally used to assess vessels in CT angiography (Figures 1.13 and 1.14)

FIGURE 1.12 Right hand of patient affected by syndactytilies: VR reconstructions (a,b,c) show the fusion

of the IV and V finger, absence of the III and fusion of the proximal phalange with the second interphalang (white arrow) Ulnar (white arrow head) and radial arteries (yellow arrow head).

• VR assigns a range of opacity values to CT numbers, giving a better definition of object contours or semi-transparent displays In this process, all CT numbers belonging to the 3D object (in the chosen threshold range) have maximum opacity, while all CT numbers outside the range have zero opacity and do not contribute to the image Since all the voxels within the CT range have maximum opacity, only the surface of the object is depicted in the shaded surface displays VR can be used for CTA, skeletal imaging, tracheobronchial imaging, colon and abdominal organ as a primary tool for image analysis In particular, in CTA, it is very useful because it shows vessel lumen and calcifications in separate colours and makes it easy to localise calcified plaques and differentiates arterial and venous ves-sels and organs with different contrast enhancement (Figures 1.15 and 1.16).

FIGURE 1.13 MIP coronal (a) and sagittal (b) images show deep inferior epigastric artery (white arrow) and

its bifurcation in medial (white arrow head) and lateral (yellow arrow head) branches.

FIGURE 1.14 Axial MIP image shows intramuscular (white arrow), subfascial (yellow arrow head) and

sub-cutaneous (white arrow head) segments of the left deep inferior epigastric perforating artery.

FIGURE 1.15 VR image of a patient affected by fibrous dysplasia with multiple bone deformities (a) (white

arrows) (b) Mandibular localization (*); (c) vertebral fracture (red circle).

FIGURE 1.16 VR images of the same patient depict femural deformity (arrow head) and superficial femural

artery (white arrow) in (a), fibular deformity in (b) and popliteal vessels in (c).