CT Colonography for Radiographers: A Guide to Performance and Image Interpretation

✍ Scribed by Joel H. Bortz (editor), Aarthi Ramlaul (editor), Leonie Munro (editor)

• Publisher: Springer
• Year: 2023
• Tongue: English
• Leaves: 405
• Edition: 2nd ed. 2023
• Category: Library

✦ Synopsis

This second edition, comprising 28 chapters, explains every aspect of the role of radiographers in performing CT colonography (CTC) and interpreting CTC images with the aim of enabling radiographers to extend the scope of their practice. It provides information required with respect to communication with the patient, procurement of informed consent, the principles of CT as well as dual-energy CT and photon counting CT, radiation dose, patient preparation and positioning, the use of contrast media, the performance of diagnostic and screening CTC studies, the interpretation and reporting of images, legal and professional requirements, and the importance of clinical audits.

A wide range of CTC findings is described and depicted, covering normal anatomy, artefacts, haemorrhoids, polyps, colon cancer, diverticular disease, lipomas, extracolonic structures, opportunistic screening for osteoporosis and metabolic associated fatty disease, and CTC in incomplete or failed colonoscopy. The role of other modalities such as ultrasound, magnetic resonance imaging, and nuclear medicine in colorectal cancer patients is discussed. In addition, the text covers the role of artificial intelligence and machine learning in imaging of the colon for the detection of polyps, diagnosis and staging of colorectal cancer. Lastly, a chapter focusing on self-assessment of image interpretation will aid learning.

This book provides the support that radiographers need in order to perform CTC studies to the standard required in terms of advances in imaging and interpretation of images.

✦ Table of Contents

Foreword
Preface
Acknowledgements
Contents
About the Authors
Abbreviations
1: Introduction
References
2: Patient-Centred Communication in Imaging
2.1 Introduction
2.2 What Is Communication?
2.3 Verbal and Nonverbal Communication
2.4 Sign, Symbols, and Codes
2.5 Denotative and Connotative Meanings
2.6 Ensuring a Successful CTC Study: Suggested Communication Materials to Inform Patients of Their Responsibilities
2.7 CTC Examinations and Patient Feedback
2.8 Readability of Imaging Reports
2.9 Readability of Text of Instructions and Informed Consent for Patients
2.10 Summary
References
3: Informed Consent
3.1 Introduction
3.2 What Is Consent?
3.2.1 Valid Consent
3.3 Why Informed Consent in CTC?
3.3.1 Informed Consent in Terms of the Use of Artificial Intelligence
3.4 The Legal Aspects of Consent
3.5 Patient Information
3.6 Risks Associated with CTC Procedures
3.7 The Duty of Consent and the Role of a CTC Radiographer
3.8 Good Practice in Information Giving
3.9 Clinical Audit to Include Informed Consent and Patient Information
3.10 Summary
References
4: Principles of CT and Hybrid Imaging
4.1 Introduction
4.2 Principles of CT
4.2.1 The X-ray Tube
4.2.2 What Are We Imaging?
4.3 Tomographic Reconstruction: Backprojection
4.3.1 Backprojection: An Example
4.4 Tomographic Reconstruction: Iterative Reconstruction
4.5 CT Numbers
4.6 Multi-Slice CT
4.7 Other Considerations
4.8 Hybrid Imaging
4.9 Summary
References
5: Principles of Radiation Dose in CT and CT Colonography
5.1 Introduction
5.2 Radiation Units
5.3 CT-Specific Radiation Dose Measures
5.3.1 The CTDI Measurement
5.3.2 Limitations of CTDI
5.4 Effective Dose
5.5 Low-Dose CTC
5.6 Dosimetric Considerations of Dual-Energy CT (DECT)
5.7 Dose for Clinical Audits
5.8 Summary
References
6: Dose Optimisation in CT Colonography
6.1 Introduction
6.2 Justification
6.3 Optimisation
6.3.1 Risk
6.4 Patient Dose in CT: Controllable and Built-in Factors
6.4.1 Tube Current
6.4.2 Automatic Tube Current Modulation
6.4.3 Tube Voltage
6.4.4 Iterative Reconstruction
6.4.4.1 Use of Artificial Intelligence in CT Image Reconstruction
6.4.5 Pre-patient Beam Filter
6.4.6 Active Collimators: Over-Ranging
6.4.7 Detector Material
6.4.8 Shielding
6.4.9 Pitch
6.4.10 Slice Thickness
6.4.11 Matrix Size
6.5 Other Practical Dose Saving Approaches
6.6 Diagnostic Reference Levels as an Optimisation Tool
6.7 Ethics in Radiology Imaging
6.8 Conclusion
References
7: Overview of CTC in Imaging the Colon
7.1 Introduction
7.2 Reasons for Referral to CTC
7.3 Development of CTC
7.3.1 Scanner Technology
7.3.2 Interpretation Methods
7.4 Evolution of the Technique
7.4.1 Bowel Preparation
7.4.2 Insufflation
7.5 Limitations of CTC
7.6 Team Approach and Training
7.7 Published Documentation Which Has Influenced CTC
7.8 CTC in the Future
7.9 Summary
References
8: The Role of Contrast Media in CTC: Types, Usage, Allergic Reactions, and Patient Safety
8.1 Introduction
8.2 Oral Contrast Within Bowel Preparation
8.3 Colonic Insufflation with CO2 and Perforation
8.4 Antispasmodic Drugs
8.5 Intravenous Contrast
8.6 Summary
References
9: Preparation of CTC Patient: Diet, Bowel Preparation, the Role of Tagging, and Methods of Colonic Insufflation
9.1 Introduction
9.2 Bowel Preparation
9.3 Colonic Preparation
9.4 Recommended Bowel Preparation Including Diet
9.4.1 Non-cathartic Options for CTC
9.5 CTC Colonic Insufflation
9.5.1 Carbon Dioxide Versus Room Air for Colonic Insufflation
9.5.2 Manual Insufflation Using Room Air or Carbon Dioxide
9.5.3 Automated Pressure-Controlled Insufflation with Carbon Dioxide
9.6 Perforation Risks
9.7 Summary
References
10: CTC Technique and Image Interpretation Methods
10.1 Introduction
10.2 Indications and Contraindications
10.3 Colonic Classifications
10.4 Positioning and Introduction of CO2
10.5 Evaluation of Polypoidal Lesions
10.6 Diagnostic CTC Following Incomplete OC
10.7 Diagnostic CTC Versus Colon Capsule Endoscopy Following Incomplete OC
10.8 Tattooing to Identify Polyps and CRC Lesions During Endoscopy
10.9 Extracolonic Findings
10.10 Interpretation
10.11 Methods and Software to View CTC Images
10.12 Summary
References
11: Anatomy of the Colon: Rectum to Ileocaecal Valve
11.1 Introduction
11.2 Anatomy of the Bowel Wall
11.3 Colon Anatomy
11.3.1 Rectum and Valves of Houston
11.3.2 Rectosigmoid Junction
11.3.3 Descending Colon
11.3.4 Splenic Flexure
11.3.5 Transverse Colon
11.3.6 Hepatic Flexure
11.3.7 Ascending Colon
11.3.8 Ileocaecal Valve (ICV)
11.3.9 Caecum
11.3.10 Appendix
11.4 Malrotation of the Bowel
11.4.1 Mobility of Colon Segments
11.5 Extrinsic Impressions
11.6 Salient Points of CTC Anatomy
11.7 Summary
References
12: CTC Traps and Artefacts
12.1 Introduction
12.2 General Principles
12.2.1 Cathartic Preparation and the Use of Tagging Solutions
12.2.1.1 Retained Faecal Matter
12.2.2 Electronic Cleansing
12.2.3 Sigmoid Diverticular Disease
12.2.4 Morphology of Polyps
12.2.5 Anatomical Locations and Structures
12.2.6 External Impressions of Organs and Bony Structures on the Colon
12.2.7 Position of the Catheter
12.2.8 Movement Artefacts
12.2.8.1 ‘Dense Waterfall’ Sign
12.2.9 Beam Hardening Artefacts
12.2.10 Ingested Artefacts
12.2.11 Mucus Strand
12.2.12 Tampon and Vaginal Pessary
12.3 Summary
References
13: Internal Haemorrhoids, Anal Papilla, and Other Anorectal Lesions
13.1 Introduction
13.2 Rectal Tube Position
13.3 Definition and Causes of Haemorrhoids
13.4 Anatomical Location of Internal and External Haemorrhoids
13.4.1 2D and 3D Architecture of Internal Haemorrhoids
13.5 Other Anorectal Pathology
13.5.1 Anal Papilla
13.5.2 Difference Between an Anal Papilla and a Rectal Polyp
13.5.3 Rectal Tumours
13.6 Valves of Houston
13.7 Rectal Varices
13.8 Summary
References
14: Polyps: Types and Sizes
14.1 Introduction
14.2 Definition of Colon Polyps, Adenoma, and Lesion
14.3 Polyp Morphology, Prevalence Range, and Need for Accurate Measurements
14.4 Polyp Measurement
14.5 Reporting Polyps: C Classification
14.6 Natural History of Polyps According to Lesion Size
14.7 Small Lesions (6–9 mm)
14.8 Advanced Adenoma
14.9 Adenomatous Polyps
14.9.1 Tubular Adenomas
14.9.2 Tubulovillous Adenomas
14.9.3 Villous Adenomas
14.10 Hyperplastic Polyps
14.11 Carpet Lesions
14.12 Serrated Lesions of the Colon and Rectum
14.13 Non-neoplastic Mucosal Lesions
14.14 Submucosal Lesions
14.14.1 Neoplastic Intramural Submucosal Lesions
14.14.2 Non-neoplastic Submucosal Lesions
14.15 Dual-Energy CT for Polyp Detection
14.16 Artificial Intelligence for Polyp Detection
14.17 Summary
References
15: The Adenoma-Carcinoma Sequence, Management, and Treatment of Colon Cancer
15.1 Introduction
15.2 Benign Colorectal Polyps, Precursor Lesions, and Histology
15.3 Colorectal Cancer Pathways
15.3.1 Adenoma-Carcinoma Pathway
15.3.2 Serrated Polyp-Carcinoma Pathway Sequence
15.4 Hereditary Colorectal Cancer Syndromes
15.5 Preoperative CTC in CRC Patients
15.6 Imaging Modalities in Preoperative Evaluation of CRC
15.7 Treatment of CRC
15.7.1 Surgery
15.7.2 Chemotherapy and Radiotherapy
15.7.2.1 Chemotherapy
15.8 Radiation Therapy
15.8.1 Treatment of CRC by Stage
15.9 Dual-Energy Computed Tomography
15.10 Artificial Intelligence for Diagnosis and Staging of CRC
15.11 AI Applications in Radiation Therapy
15.12 Summary
References
16: Colonic Diverticular Disease
16.1 Introduction
16.2 Acute Diverticulitis Is Contraindicated in a CTC Study
16.3 Pathogenesis and Cause of Colonic Diverticular Disease
16.4 Chronic Diverticular Disease Pathological Features
16.5 Severity Score of Diverticular Disease
16.6 CTC in Patients with Diverticular Disease
16.7 Visualisation of Diverticula on 2D and 3D CTC Images
16.8 Role of Antispasmodics
16.9 Inadequate Luminal Distension
16.9.1 Possible Causes of Inadequate or No Luminal Distension in the Presence of Pain
16.10 Complications of Diverticular Disease
16.10.1 Clinical Features of Diverticulitis
16.10.2 Chronic Diverticulitis
16.11 Diagnostic Modalities for Acute Diverticulitis
16.11.1 Contrast Enemas
16.11.2 Imaging and Treatment Options for Complicated Diverticulitis
16.12 Differentiation of Chronic Diverticular Disease from an Underlying Tumour
16.13 Summary
References
17: Lipomas of the Colon
17.1 Introduction
17.2 Lipoma Symptoms and Sites in the Colon
17.3 Gender Prevalence and Incidence
17.4 Anatomical Sites and Morphology of Lipomas
17.5 Lipoma ‘Signs’ at Optical Colonoscopy
17.6 Summary
References
18: Extracolonic Findings, Their Clinical Significance, and the Role of Opportunistic Screening
18.1 Introduction
18.2 Benefits of Visualising Extracolonic Organs and Tissues
18.2.1 Negative Aspects of ECFs
18.3 Clinical Importance of ECFs: Low, Moderate, and High
18.4 Classification of ECFs
18.5 Examples of ECF Images
18.5.1 E1: Not of Clinical Importance
18.5.2 E2: Low Clinical Importance
18.5.3 E3: Moderate Clinical Importance
18.5.4 E4: High Clinical Importance
18.6 Bone Mineral Density Assessment
18.7 Calcific Score: Abdominal Aortic Calcification
18.8 Inguinal Hernias as Extracolonic Findings: An Overview, Types of Hernia, Complications, and Repair
18.8.1 Types of Hernias
18.8.2 Tips to Determine Whether Small or Large Bowel Is Trapped in an Inguinal Hernia
18.8.3 Frequency of Inguinal Hernias
18.8.4 Complications
18.8.5 Surgical Repair Procedures
18.9 Air in Vagina
18.10 Comparison of ECFs and Clinical Outcomes at Screening and Diagnostic CTC
18.11 Summary
References
19: Metabolic-Associated Fatty Liver Disease: Opportunistic Screening at CT Colonography
19.1 Introduction
19.2 Importance of Reporting MAFLD Seen at CTC: E-Classification
19.3 MAFLD and Non-alcoholic Steatohepatitis (NASH)
19.4 Metabolic Syndrome
19.4.1 Clinical Outcomes of Metabolic Syndrome
19.5 Cryptogenic Cirrhosis
19.6 NAFLD in Terms of Alcohol Consumption
19.7 Diagnosis of MAFLD
19.7.1 Measuring Attenuation Values: Liver and Spleen
19.8 Serum Liver Enzyme Tests
19.9 Fatty Sparing in the Liver
19.10 How to Distinguish MAFLD from Alcoholic Liver Disease
19.11 Main Points of MAFLD Diagnosis and Patient Management
19.11.1 Who Should Inform Patients with MAFLD of Its Potential Risks?
19.12 Summary
References
20: CTC for Incomplete and Failed Colonoscopy Cases
20.1 Introduction
20.2 Colon Capsule Endoscopy (CCE)
20.3 Reasons for Incomplete and Failed Optical Colonoscopy
20.4 Advantages of CTC
20.5 Incomplete Optical Colonoscopy: Role of Radiology Imaging
20.6 Summary
References
21: Good Practice Reporting in CTC
21.1 Introduction
21.2 Reading and Interpretation Requirements
21.3 Interpretation Tools for CTC
21.4 Role of Artificial Intelligence in CTC
21.5 Dictation Template
21.6 Clinical Audit
21.7 Summary
References
22: The Role of Ultrasound and Magnetic Resonance Imaging in the Evaluation of Colon Cancer
22.1 Introduction
22.2 Ultrasound
22.3 Magnetic Resonance Imaging, MR Colonography, and MRI Rectum
22.3.1 MR Colonography
22.3.2 Rectal MRI
22.4 Comparison of the Accuracy of Imaging Modalities in TNM Staging of Colon Cancer
22.5 Advancements in MR Imaging of CRC
22.6 Evolving Role of Artificial Intelligence (AI) in Imaging of CRC
22.7 Summary
References
23: Role of Nuclear Medicine in the Evaluation of Colon Cancer
23.1 Introduction
23.2 Nuclear Medicine Imaging in Colon Cancer
23.2.1 Radiopharmaceutical
23.2.2 PET-CT: Patient Preparation
23.2.3 How to Perform a PET Study
23.2.4 Interpretation
23.2.5 Advantages of PET Imaging for CRC Patients
23.3 The Role of Artificial Intelligence (AI) in PET-CT
23.4 Clinical Audits for Good Practice
23.5 Summary
References
24: Legal and Professional Requirements: A Framework for Practice
24.1 Introduction
24.2 Employment
24.3 Professional Regulation
24.4 Duty and Standard of Care
24.5 A Framework for Practice
24.6 Summary
References
25: Artificial Intelligence and Machine Learning in Cross-Sectional Imaging
25.1 Introduction
25.2 Artificial Intelligence, Machine Learning, and Deep Learning
25.2.1 Machine Learning
25.2.1.1 Supervised Learning
25.2.1.2 Unsupervised Learning
25.2.1.3 Semi-supervised Learning
25.2.1.4 Reinforcement Learning
25.2.2 Deep Learning
25.3 Impact of AI on Radiography
25.4 Ethical Considerations for AI-Enabled Healthcare Settings and Systems
25.4.1 Bias
25.4.2 Interpretability and Accountability
25.4.3 Data Privacy and Security
25.5 AI-Enabled Image Interpretation in Cross-Sectional Imaging and CTC
25.6 Conclusion
References
26: Dual-Energy CT and Photon Counting CT
26.1 Introduction
26.2 X-Ray Interaction Mechanisms
26.3 Material Decomposition
26.4 Different Approaches to DECT
26.4.1 Dual-Source CT
26.4.2 Twin Beam Dual-Energy
26.4.3 Rapid Tube Potential Switching
26.4.4 Dual-Layer Detectors
26.5 The Use of DECT in CTC
26.6 Photon Counting CT
26.7 Summary
References
27: Application of Clinical Audit Principles for Good Practice in CT Colonography
27.1 Introduction
27.2 The Value of Audit Data
27.3 Audit Cycle
27.3.1 Preparing for an Audit
27.3.2 Criteria and Standard to Be Set
27.3.3 Data Collection
27.3.4 Data Analysis
27.3.5 Improvements and Maintenance
27.4 Is a Clinical Audit the Same as Research?
27.5 Proposed Layout of a Clinical Audit Report
27.6 Summary
References
28: Self-Assessment of CT Colonography Images
28.1 Introduction
28.2 Self-Assessment Questions
28.3 Answers
Glossary
Index