ABDOMINAL IMAGING 2 VOLSET: Expert Radiology Series (Expert Consult: Online and Print)

Description

Abdominal Imaging, a title in the Expert Radiology Series, edited by Drs. Dushyant Sahani and Anthony Samir, is a comprehensive 2-volume reference that encompasses both GI and GU radiology. It provides richly illustrated, advanced guidance to help you overcome the full range of diagnostic, therapeutic, and interventional challenges in abdominal imaging and combines an image-rich, easy-to-use format with the greater depth that experienced practitioners need. Online access at expertconsult.com allows you to rapidly search for images and quickly locate the answers to any questions. Cover Front Matter Abdominal Imaging Copyright Dedication Contributors Preface Plain Radiography of the Abdomen TECHNICAL ASPECTS PROS AND CONS CONTROVERSIES NORMAL ANATOMY Intraluminal Gas Extraluminal Gas Calcification Soft Tissues and Bone Artifacts PATHOLOGIC FINDINGS Renal Colic Intestinal Obstruction Perforation of the Intestine Appendicitis Intussusception Body Packers PATHOPHYSIOLOGY Small Bowel Colon Miscellaneous Findings Suggested Readings References Fluoroscopic Study of the Abdomen and Fluoroscopic Contrast Media TECHNICAL ASPECTS Fluoroscopy History Patient Preparation Fluoroscopic Examinations Gastrointestinal Fluoroscopic Procedures Genitourinary Fluoroscopic Procedures Interventional Procedures Other Examinations FLUOROSCOPIC CONTRAST AGENTS Barium Water-Soluble Contrast Agents Gastrografin Oral Administration Enemas or Enterostomy Instillations Oral Gastrografin Indications Equipment Factors Patient Factors Side Effects Barium Iodinated Oral Contrast Media PROS AND CONS Suggested Readings References Ultrasound Physics and Instrumentation: A Condensed View TECHNICAL ASPECTS ULTRASOUND WAVES TRANSDUCERS Transducer Selection (Fig. 3-2) Linear Sequential Array Curved Array Matrix Array Transducer Care KNOBOLOGY IMAGING ARTIFACTS Propagation Artifact Reverberation Artifact Comet Tail Artifact Refraction Artifact Side Lobe Artifact Mirror Image Artifact Shadowing Artifact Acoustic Enhancement PROS AND CONS CONTROVERSIES Suggested Readings References Abdominal Ultrasound Imaging TECHNICAL ASPECTS PROS AND CONS CONTROVERSIES IMAGING OF SPECIFIC AREAS Liver and Ducts Gallbladder Kidney and Spleen Pancreas Urinary Bladder Suggested Readings References Harmonic Imaging TECHNICAL ASPECTS Why Harmonic Imaging? Grating Lobes Slice Thickness Side Lobes Reverberation Artifacts How Harmonics Improve Imaging EQUIPMENT PROCESS TECHNICAL CHALLENGE CLINICAL APPLICATIONS “Technically Difficult” Patients Cystic Structures Major Vascular Structures Contrast-Enhanced Ultrasonography Suggested Readings References Doppler Ultrasound Imaging TECHNICAL ASPECTS PROS AND CONS Pros Cons CONTROVERSIES NORMAL ANATOMY Portal System Hepatic Veins Renal Arteries Renal Veins Abdominal Aorta Inferior Vena Cava Abdominal Vessels Celiac Artery Splenic Artery Hepatic Artery Superior Mesenteric Artery Inferior Mesenteric Artery IMAGING OF SPECIFIC CONDITIONS Portal Hypertension Common Causes Pathophysiology Diagnostic Criteria Gray Scale Imaging Findings Doppler Imaging Findings Portal Vein Hepatic Artery Hepatic Vein (Budd-Chiari Syndrome) Transjugular Intrahepatic Portosystemic Shunt (TIPS) Doppler Imaging Findings Liver Transplantation Mesenteric Ischemia Renal Artery Stenosis Renal Vein Thrombosis Medical Renal Disease Renal Transplantation Parenchymal Complications Vascular Complications Aorta Aneurysm Aortic Dissection Inferior Vena Cava SUMMARY Suggested Readings References Four-Dimensional Ultrasound Imaging TECHNICAL ASPECTS PROS AND CONS Benefits of 4D Ultrasound Imaging Limitations Suggested Readings References Contrast Media and Contrast-Enhanced Ultrasound Evaluation TECHNICAL ASPECTS Physical Properties Mechanical Index Applications of Microbubbles in Ultrasonography Untargeted Ultrasound Contrast Agents Targeted Ultrasound Contrast Agents Targeting Inflammations Targeting Cancers PROS AND CONS Suggested Readings References Principles of CT Physics TECHNICAL ASPECTS 64-Slice CT Scanners Flying Focal Spot Function Dual-Source CT Scanners Reconstruction Algorithms Pitch, Noise, and Radiation Dose Reducing Radiation Dose Artifacts of Multislice Scanners Cone Beam Artifact Windmill Artifact Zebra Artifact CONCLUSION References Instrumentation and Radiation Safety TECHNICAL ASPECTS CT Instrumentation Radiation Safety Summary PROS AND CONS Suggested Readings References Recent Advances TECHNICAL ASPECTS Advances in X-Ray Tube Dual-Energy CT Clinical Applications of Dual-Energy CT in the Abdomen Advances in Detector Technology Wide-Area Detector New Detector Materials Sandwich Detectors New Reconstruction Algorithms Perfusion CT Technique Abdominopelvic Applications of Perfusion CT Liver Tumors Pancreatic Tumors Colorectal Cancer Prostate Cancer Lymphoma Nononcologic Applications Suggested Readings References CT Contrast Media and Principles of Contrast Enhancement CONTRAST ENHANCEMENT PRINCIPLES TYPES OF CONTRAST MEDIA High Osmolar Contrast Media Low Osmolar Contrast Media Isosmolar Contrast Media PHARMACOKINETICS FACTORS AFFECTING ENHANCEMENT Organ-Specific Factors Liver Pancreas Kidneys Patient-Related Factors Injection-Related Factors Test Bolus Contrast Medium Concentration CONTRAST-INDUCED NEPHROPATHY Risk Factors Preexisting Renal Disease Diabetes Age Other Risk Factors Prevention ADVERSE EFFECTS OF CONTRAST MEDIA General Adverse Reactions Acute Reactions Delayed Reactions Pathophysiology of General Adverse Effects Treatment Organ-Specific Adverse Effects Prevention Suggested Readings References CT Protocols for Abdomen and Pelvis TECHNICAL ASPECTS Oral Contrast Media Need for Oral Contrast Media Intravenous Contrast Media Screening Patients before Use Intravenous Contrast Media Protocols Timing of Bolus Contrast Injection Rate and Intravenous Access Technical Parameters Scan Coverage Tube Potential Tube Current Pitch Reconstructed Slice Thickness Volume Acquisition and Postprocessing USE OF CT IN SPECIFIC SITUATIONS CT in the Pregnant Patient CT in Very Large Patients CONCLUSION Suggested Readings References Principles of MRI Physics TECHNICAL ASPECTS Magnetization and Protons Radiofrequency Excitation T1 and T2 Relaxation Image Acquisition Spatial Encoding Fourier Transform Analysis and k-Space Suggested Readings MRI Instrumentation and Safety TECHNICAL ASPECTS Instrumentation MRI Magnets Permanent Magnets Resistive Magnets Superconducting Magnets Radiofrequency Coils Radiofrequency System (“Radiofrequency Chain”) Computer and Software Safety Cryogen Safety Eddy Currents and Acoustic Noise Ferromagnetic Materials and Objects Specific Absorption Rate Sedation Pregnancy and Fetus Risk Gadolinium and Nephrogenic Systemic Fibrosis CONTROVERSIES References MRI Pulse Sequences TECHNICAL ASPECTS T1-Weighted Techniques Gradient-Recalled-Echo Sequences Fat Suppression Out-of-Phase Imaging Contrast-Enhanced Sequences T2-Weighted Techniques Spin-Echo Sequences Fast Spin-Echo Sequences and Single-Shot Fast Spin-Echo Sequences Fat-Suppressed T2-Weighted Sequences Fast Advanced Spin Echo General Strategies Suggested Readings MRI Artifacts TECHNICAL ASPECTS Types of Artifacts Motion Artifacts Chemical Shift Artifact Phase-Wrap Artifact/Aliasing Artifact Frequency-Encoding Artifacts Susceptibility Artifact (T2* Effect) and Paramagnetic Effects Patient Compliance and Capacity for Cooperation Suggested Readings Contrast Media and Contrast-Enhanced MRI TECHNICAL ASPECTS Principle of Relaxivity Chemical Structure of Currently Approved Chelates of Gadolinium Biodistribution Phases of Vascular and Tissue Enhancement PROS AND CONS Suggested Readings References MR Angiography TECHNICAL ASPECTS Time-of-Flight MRA TOF Principles Imaging Parameters 2D versus 3D Sequences Phase-Contrast MRA Phase-Contrast Imaging Principles 2D and 3D Phase-Contrast Imaging Advantages and Disadvantages Contrast-Enhanced MRA Pulse Sequences Contrast Injection and Bolus Timing Dynamic or Time-Resolved MRA PROS AND CONS Suggested Readings Advanced MRI Applications TECHNICAL ASPECTS Parallel Imaging Clinical High Field Strength Imaging with 3.0-T Imaging Novel Tissue-Specific Contrast Agents Liver-Specific MRI Contrast Agents Mangafodipir Trisodium Gadolinium Chelates Ferumoxides Ferucarbotran Blood-Pool Contrast Agents Lymph Node–Specific MRI Contrast Agents Diffusion-Weighted Imaging in the Abdomen Perfusion Imaging and Dynamic Contrast-Enhanced MRI CONTROVERSIES Suggested Readings References PET/CT Technique and Instrumentation TECHNICAL ASPECTS Instrumentation Considerations Technique Considerations Protocols in Practice PROS AND CONS CONTROVERSIES SUMMARY Suggested Readings References Pearls and Pitfalls in PET and PET/CT Interpretation TECHNICAL ASPECTS PRINCIPLES General Interpretation Specific Interpretation Artifacts Attenuation Correction Misregistration PROS AND CONS CONTROVERSIES IMAGING OF SPECIFIC LESIONS OR REGIONS Nonmalignant Hypermetabolic Lesions Liver and Spleen Kidney and Urinary Tract Pancreas Adrenal Gland Hypometabolic Lesions Gastrointestinal Tract Reproductive Tract Uterus Ovary Prostate SUMMARY Suggested Readings References PET and PET/CT Clinical Applications IMAGING OF SPECIFIC AREAS Gastrointestinal Tract Esophageal Carcinoma Colorectal Carcinoma Diagnosis Staging Metastatic Disease Restaging Future PET/CT Applications for the Patient with Colorectal Disease Other Gastrointestinal Malignancies Gastric Cancer Tumors of the Small Intestine Gastrointestinal Stromal Tumors Gynecologic Malignancy Cervical Cancer Ovarian Cancer Endometrial Cancer Suggested Readings References Principles of 3D Postprocessing TECHNICAL ASPECTS Data Handling MDCT CT of Liver and Biliary Tree CT of Pancreas CT of Urinary Tract CT in Lower Abdominal Pain CT Enterography Ultrasonography MRI Segmentation of Abdominal Viscera Filtering of 3D Images Visualization of 3D Image Virtual Endoscopy Colon Vessels Computer-Aided Detection PROS AND CONS Suggested Readings References Advanced Applications in Postprocessing TECHNICAL ASPECTS Virtual Endoscopy Scan Parameters Colon Vascular Imaging Biliary and Urinary Tracts Segmentation of the Desired Volume Creating a Fly-Through Path Virtual Endoscopy of Upper Gastrointestinal Tract Virtual Endoscopy of the Colon Bowel Preparation Interpretation Virtual Cholangioscopy Virtual Pancreatoscopy Volumetry Liver and Spleen Kidney Tumor Volumes Computer-Aided Techniques Colon Liver Small Bowel Kidney SUMMARY Suggested Readings References Ureteral and Kidney Stones ETIOLOGY PREVALENCE AND EPIDEMIOLOGY CLINICAL PRESENTATION PATHOPHYSIOLOGY IMAGING Radiography CT MRI Ultrasonography Imaging Algorithm DIFFERENTIAL DIAGNOSIS TREATMENT Medical Treatment Surgical Treatment Suggested Readings References Acute Appendicitis ETIOLOGY EPIDEMIOLOGY CLINICAL PRESENTATION PATHOPHYSIOLOGY PATHOLOGY IMAGING Radiography CT MRI Ultrasonography Imaging Algorithm DIFFERENTIAL DIAGNOSIS TREATMENT Suggested Readings References Hollow Viscus Perforation ETIOLOGY PREVALENCE AND EPIDEMIOLOGY CLINICAL PRESENTATION PATHOPHYSIOLOGY PATHOLOGY IMAGING Radiography CT Imaging Algorithm DIFFERENTIAL DIAGNOSIS TREATMENT Medical Treatment Surgical Treatment Suggested Readings References Acute Gastrointestinal Bleeding ETIOLOGY PREVALENCE AND EPIDEMIOLOGY CLINICAL PRESENTATION PATHOPHYSIOLOGY IMAGING Radiography CT Nuclear Medicine Imaging Algorithm DIFFERENTIAL DIAGNOSIS TREATMENT Medical Treatment Surgical Treatment Suggested Readings References Conventional Imaging of the Stomach and Duodenum TECHNICAL ASPECTS The Double-Contrast Examination Technique Stomach Views Duodenum Views Single-Contrast Examination PROS AND CONS CONTROVERSIES NORMAL ANATOMY Anatomic Relationships of the Stomach and Duodenum Blood Supply Arterial Supply to the Stomach Venous Drainage of the Stomach Lymphatic Drainage of the Stomach Arterial Supply of the Duodenum Venous Drainage of the Duodenum Lymphatic Drainage of the Duodenum PATTERNS AND APPEARANCES ON BARIUM STUDIES Gastric Ulcers Superficial Gastric Erosions Duodenal Ulcers Narrowing of the Stomach (Linitis Plastica Pattern) Filling Defects in the Stomach Thickening of Gastric Folds Extrinsic Lesions Widening of the Duodenal “C” Loop Suggested Readings References CT of the Stomach and Duodenum TECHNICAL ASPECTS CT OF THE STOMACH Inflammatory Disease Gastric Ulcer Generalized Gastric Wall Thickening Neoplasms Primary Malignant Neoplasms Staging of Gastric Cancer Gastric Lymphoma Other Tumors Submucosal Lesions Gastrointestinal Stromal Tumors Leiomyosarcoma Metastasis Miscellaneous Disorders Gastric Varices Gastric Distention CT OF THE DUODENUM Inflammatory Conditions Duodenal Diverticulum Neoplasm Malignant Tumors Secondary Involvement Other Tumors Trauma Suggested Readings References Anatomic Variants of the Stomach and Duodenum CONGENITAL ABNORMALITIES Microgastria Isolated Dextrogastria Gastric Duplication Duodenal Duplication Duodenal Diverticulum ACQUIRED POSITIONAL ABNORMALITIES Gastric Hernia Herniations Volvulus Organoaxial Volvulus Mesoaxial Volvulus Malrotation The Postoperative Stomach Suggested Readings References Benign Mucosal Diseases of the Stomach ETIOLOGY PREVALENCE AND EPIDEMIOLOGY Benign Diseases Causing Mucosal Ulcerations Benign Diseases Causing Polyps/Masses Benign Diseases Causing Diffuse Mucosal Abnormalities CLINICAL PRESENTATION NORMAL ANATOMY PATHOLOGY IMAGING Ulcers Radiography CT Nuclear Medicine Polyps/Masses Radiography CT Diffuse Mucosal Disease Radiography CT Nuclear Medicine PET/CT Imaging Algorithm DIFFERENTIAL DIAGNOSIS TREATMENT Medical Treatment Surgical Treatment Suggested Readings References Malignant Mucosal Diseases of the Stomach ETIOLOGY PREVALENCE AND EPIDEMIOLOGY CLINICAL PRESENTATION NORMAL ANATOMY PATHOLOGY IMAGING Malignant Mucosal Disease Radiography CT MRI Ultrasonography Nuclear Medicine PET/CT Imaging Algorithm DIFFERENTIAL DIAGNOSIS TREATMENT Medical Treatment Surgical Treatment Suggested Readings References Gastric Stromal Tumors INTRODUCTION PREVALENCE AND EPIDEMIOLOGY CLINICAL PRESENTATION PATHOLOGY IMAGING Radiography CT MRI PET/CT TREATMENT Medical Treatment Surgical Treatment Suggested Readings References Gastric Outlet Obstruction ETIOLOGY PREVALENCE AND EPIDEMIOLOGY CLINICAL PRESENTATION ANATOMY PATHOLOGY IMAGING Radiography CT MRI Ultrasonography Nuclear Medicine PET/CT Imaging Algorithm DIFFERENTIAL DIAGNOSIS TREATMENT Medical Treatment Surgical Treatment Suggested Readings References Abnormal Positions of the Stomach ETIOLOGY DEFINITIONS, PREVALENCE, AND EPIDEMIOLOGY CLINICAL PRESENTATION PATHOPHYSIOLOGY PATHOLOGY IMAGING Radiography Ultrasonography CT MRI Imaging Algorithm DIFFERENTIAL DIAGNOSIS TREATMENT Medical Treatment Surgical Treatment Suggested Readings References Gastric Function Imaging Techniques TECHNICAL ASPECTS Radiopharmaceuticals Pharmacologic Adjuncts Technique PROS AND CONS CONTROVERSIES References Clinical Applications of Gastric Function Imaging EMBRYOLOGY GASTRIC ANATOMY AND FUNCTION NORMAL GASTRIC ANALYSIS CURVES AND IMAGE PATHOPHYSIOLOGY Factors Affecting Gastric Emptying Mechanical Delayed Gastric Emptying Functional Delayed Gastric Emptying References Conventional Imaging of the Small Bowel TECHNICAL ASPECTS Small Bowel Follow-Through Peroral Pneumocolon Enteroclysis Single-Contrast Enteroclysis Double-Contrast Enteroclysis Air-Contrast Enteroclysis Methylcellulose-Contrast Enteroclysis Small Bowel Studies Using Water-Soluble Contrast Agents Retrograde Examinations of the Small Intestine Ileostomy Enema PROS AND CONS Small Bowel Follow-Through Single-Contrast Enteroclysis Air-Contrast Enteroclysis Methylcellulose-Contrast Enteroclysis NORMAL ANATOMY SPECIFIC INDICATIONS Abdominal Pain Chronic Diarrhea Small Bowel Obstruction Unexplained Gastrointestinal Bleeding Malabsorption Suggested Readings References CT of the Small Bowel TECHNICAL ASPECTS “Routine” CT of the Abdomen and Pelvis CT Enterography CT Enteroclysis PROS AND CONS CONTROVERSIES NORMAL ANATOMIC IMAGING FINDINGS Suggested Readings References Ultrasound Imaging of the Small Bowel TECHNICAL ASPECTS IMAGING Normal Appearance The Abnormal Small Bowel CONTROVERSIES References MRI of the Small Bowel TECHNICAL ASPECTS Intraluminal Contrast Agents Pulse Sequences Coil Selection MR Enteroclysis PROS AND CONS NORMAL ANATOMY IMAGING Normal Appearance Small Bowel Obstruction Crohn’s Disease Small Bowel Neoplasms Suggested Readings References Nuclear Medicine Techniques for the Small Bowel IMAGING STUDIES Imaging of Inflammation and Infection Principle Technical Aspects Image Interpretation Pros and Cons Other Radiopharmaceuticals 99mTc-Fanolesomab (NeutroSpec) 99mTc-Sulesomab (LeukoScan) 18F-Fluorodeoxyglucose (FDG)-PET Gallium-67 Citrate Imaging of Meckel’s Diverticulum Principle Technical Aspects Image Interpretation Pros and Cons Imaging for Gastrointestinal Bleeding Principle Technical Aspects Image Interpretation Pros and Cons Imaging of Tumors Principle Technical Aspects Image Interpretation Pros and Cons Imaging of Small Bowel Motility Principle Technical Aspects Pros and Cons NONIMAGING TECHNIQUES Schilling Test Principle Breath Test for Small Bowel Bacterial Overgrowth Principle Protein-Losing Enteropathy Bile Salt Malabsorption Suggested Readings References Small Bowel Obstruction SMALL BOWEL OBSTRUCTION: GENERAL CONSIDERATIONS Etiology Prevalence and Epidemiology Clinical Presentation Anatomy Pathology Imaging Radiography Abdominal Radiography Intraluminal Contrast Radiography Barium Enteroclysis CT MRI Ultrasonography Imaging Algorithm Differential Diagnosis Treatment Medical Treatment Surgical Treatment BENIGN CAUSES OF SMALL BOWEL OBSTRUCTION Etiology Prevalence and Epidemiology Clinical Presentation Pathophysiology Pathology Imaging Radiography CT MRI Ultrasonography Nuclear Medicine Imaging Algorithm Treatment Medical Treatment Surgical Treatment MALIGNANT CAUSES OF SMALL BOWEL OBSTRUCTION Etiology Prevalence and Epidemiology Clinical Presentation Pathophysiology Pathology Imaging Radiography CT MRI Ultrasonography Nuclear Medicine PET/CT Imaging Algorithm Treatment Medical Treatment Surgical Treatment Suggested Readings References Acute Small Bowel Ischemia ETIOLOGY PREVALENCE AND EPIDEMIOLOGY CLINICAL PRESENTATION ANATOMY AND PATHOPHYSIOLOGY PATHOLOGY IMAGING Superior Mesenteric Artery Embolism Radiography CT MRI Ultrasonography Nuclear Medicine PET/CT Angiography Imaging Algorithm Superior Mesenteric Artery Thrombosis Radiography CT MRI Ultrasonography Nuclear Medicine PET/CT Angiography Imaging Algorithm Nonocclusive Mesenteric Ischemia Radiography CT MRI Ultrasonography Nuclear Medicine PET/CT Angiography Imaging Algorithm Mesenteric Venous Thrombosis Radiography CT MRI Ultrasonography Nuclear Medicine PET/CT Angiography Imaging Algorithm DIFFERENTIAL DIAGNOSIS TREATMENT Medical Treatment Surgical Treatment Suggested Readings References Chronic Small Bowel Ischemia ETIOLOGY PREVALENCE AND EPIDEMIOLOGY CLINICAL PRESENTATION PATHOPHYSIOLOGY PATHOLOGY IMAGING Radiography CT MRI Ultrasonography Nuclear Medicine PET/CT Angiography Imaging Algorithms DIFFERENTIAL DIAGNOSIS TREATMENT Suggested Readings References Benign Neoplasms and Wall Thickening of the Small Bowel CROHN’S DISEASE Etiology Prevalence and Epidemiology Clinical Presentation Anatomy Pathology Imaging Radiography CT MRI Ultrasonography Nuclear Medicine PET/CT Imaging Algorithm Differential Diagnosis Treatment Medical Treatment Surgical Treatment INFECTIOUS CAUSES Etiology Prevalence and Epidemiology Clinical Presentation Pathology Imaging Radiography CT MRI Ultrasonography Nuclear Medicine and PET/CT Imaging Algorithm Differential Diagnosis Treatment Medical Treatment Surgical Treatment MISCELLANEOUS CAUSES OF BENIGN SMALL BOWEL WALL THICKENING Etiology Clinical Presentation Pathology Imaging (Table 48-5; see also Fig. 48-28) Radiography CT Nuclear Medicine Differential Diagnosis Treatment Medical Treatment Surgical Treatment BENIGN NEOPLASMS OF THE SMALL BOWEL Etiology Prevalence and Epidemiology Clinical Presentation Peutz-Jeghers Syndrome Anatomy Pathology Benign Neoplasms Adenoma Lipoma Neural Tumors Vascular Tumors Leiomyoma and Gastrointestinal Stromal Tumors Polyposis and Polyposis Syndromes Tumor-like Benign Conditions Heterotopic Pancreas Hyperplasia of Brunner Gland Endometriosis Inflammatory Fibroid Polyp Heterotopic Gastric Mucosa Lymphoid Hyperplasia Mimics Imaging Solitary Benign Tumors Radiography CT MRI Ultrasonography Nuclear Medicine PET/CT Peutz-Jeghers Syndrome Radiography CT MRI Ultrasonography PET/CT Imaging Algorithm Differential Diagnosis Treatment Medical Treatment Surgical Treatment Suggested Readings References Malignant Neoplasms and Wall Thickening of the Small Bowel SECONDARY MALIGNANCIES OF THE SMALL BOWEL Etiology Clinical Presentation Pathophysiology Pathology Imaging Radiography CT MRI Ultrasonography PET/CT Imaging Algorithm Differential Diagnosis Treatment Medical Treatment Surgical Treatment PRIMARY MALIGNANCIES OF THE SMALL BOWEL Etiology Prevalence and Epidemiology Clinical Presentation Pathophysiology Pathology Imaging Radiography CT MRI Ultrasonography Nuclear Medicine PET/CT Imaging Algorithm Differential Diagnosis Treatment Suggested Readings References Small Bowel Anomalies and Variants TECHNICAL ASPECTS Plain Radiography Fluoroscopic Methods: Small Bowel Series and Enteroclysis CT MRI PROS AND CONS CONTROVERSIES NORMAL ANATOMY PATHOPHYSIOLOGY Malrotation and Nonrotation Intestinal Atresia Intussusception Internal Hernias Meckel’s Diverticulum IMAGING Malrotation and Nonrotation Radiography CT Ultrasonography Imaging Algorithms Intestinal Atresia Radiography Ultrasonography Imaging Algorithms Intussusception Radiography CT Ultrasonography Imaging Algorithms Internal Hernias Radiography CT Imaging Algorithms Meckel’s Diverticulum Radiography CT Nuclear Medicine Imaging Algorithms Suggested Readings References Conventional Imaging of the Colon and Rectum TECHNICAL ASPECTS Single-Contrast Barium Enema Examination Double-Contrast Barium Enema Examination Bowel Preparation Barium Suspension: Viscosity and Density Hypotonizing Agent Procedure Digital Rectal Examination Rectal Catheter Insertion Glucagon Barium Instillation Air Insufflation Radiographic Documentation: Spot Films and Overhead Views Erect Views Technical Modifications Peroral Pneumocolon Water-Soluble Contrast Enema Colostomy Enema PROS AND CONS COMPLICATIONS CONTROVERSIES NORMAL ANATOMY Luminal Distention Luminal Contour Mucosal Surface Variations IMAGING OF SPECIFIC LESIONS Ulcerative Colitis Early Changes Late Changes Crohn’s Disease Pseudomembranous Colitis Ischemic Colitis AIDS-Associated Colitis Radiation Colitis Diverticular Disease Diverticulitis Diverticular Abscess Lymphoid Hyperplasia Lymphoma Lipoma Extrinsic Masses Colorectal Carcinoma Metastases PATHOLOGY Dependent and Nondependent Surfaces Artifacts Suggested Readings References CT of the Colon and Rectum TECHNICAL ASPECTS Imaging Protocol Contrast Agents Intravenous Contrast Agents Luminal Contrast Agents Positive Contrast Opacification Neutral Contrast Opacification Perfusion CT PROS AND CONS NORMAL ANATOMY Characteristic Features of the Colon Variations in Colon Anatomy DIAGNOSIS Clinical Presentation IMAGING OF SPECIFIC AREAS Bowel Wall Thickening Morphology of Fat Ascites Lymphadenopathy Complications Descriptive CT Signs “Accordion” Sign “Comb” Sign “Arrowhead” Sign “Cecal Bar” Sign Imaging Algorithm White Attenuation Gray Attenuation “Water Halo” Pattern “Fat Halo” Pattern Black Attenuation Perfusion CT Suggested Readings References CT Colonography TECHNICAL ASPECTS Technique Colonic Cleansing Contraindications for Bowel Cleansing Agents Residual Stool and Luminal Fluid Tagging Colonic Distention Room Air Carbon Dioxide Technique Room Air Automated CO2 Technique Use of Spasmolytic Agents Glucagon Hyoscine Butylbromide MDCT Protocol for CT Colonography CT Colonography and Radiation Dose CT Colonography Visualization 2D Visualization 3D Visualization Newer Display Methods CT Colonography Interpretation PROS AND CONS CONTROVERSIES NORMAL ANATOMY FUTURE TRENDS AND DEVELOPMENTS PATHOPHYSIOLOGY Adenoma Adenoma Variants Adenoma Progression Classification of Adenoma Shape and Cancer Risk Adenoma Size and Cancer Risk Pathologic and Molecular Pathways from Adenoma to Carcinoma Suggested Readings References Normal Anatomy and Variants of the Colon TECHNICAL ASPECTS PROS AND CONS NORMAL ANATOMY Embryology Normal Gross Anatomy Vascular Anatomy Normal Radiologic Anatomy Barium Enema Ultrasonography CT MRI PATHOPHYSIOLOGY AND PATHOLOGIC CORRELATION Nonrotation Subhepatic Cecum Mobile Cecum Hyperrotation Inverse Cecum Retroperitoneal Cecum Retrogastric Colon Colonic Interpositions Chilaiditi’s Sign Right Lower Quadrant Position of the Sigmoid Colon Redundant Colon ANATOMIC VARIANTS Vascular Variants1,26 Pseudolesions and Pathology Mimics Pressure Effect and Displacements Pseudomass Lesions Appendiceal Variations Suggested Readings References Inflammatory and Infectious Colonic Lesions ETIOLOGY PREVALENCE AND EPIDEMIOLOGY CLINICAL PRESENTATION PATHOPHYSIOLOGY IMAGING General Considerations Length of Involvement Focal Disease (2 to 10 cm) Segmental Disease (10 to 40 cm) Diffuse Disease (Most of the Colon) Location of Involvement Cecal Region Isolated Splenic Flexure/Proximal Descending Colon Rectum Multiple Skip Regions Degree of Thickening Pattern of Enhancement Target/Double Halo Homogeneous Heterogeneous Diminished Extraintestinal Manifestations Radiography CT Normal Colon Specific Pathologic Causes of Colonic Inflammation MRI DIFFERENTIAL DIAGNOSIS TREATMENT Suggested Readings References Colonic Vascular Lesions ETIOLOGY PREVALENCE AND EPIDEMIOLOGY CLINICAL PRESENTATION PATHOPHYSIOLOGY AND PATHOLOGY Angiodysplasia Dieulafoy’s Lesion Congenital Arteriovenous Malformations Hemangioma IMAGING Angiodysplasia Barium Studies CT MRI Nuclear Medicine Colonoscopy Angiography Hemangiomas Radiography Barium Studies CT MRI Endoscopy Angiography Dieulafoy’s Lesion Nuclear Scintigraphy Endoscopy Angiography Congenital Arteriovenous Malformations CT Endoscopy Angiography TREATMENT Medical Treatment Surgical Treatment Suggested Readings References Colon Cancer and Screening Strategies ETIOLOGY PREVALENCE AND EPIDEMIOLOGY CLINICAL PRESENTATION PATHOPHYSIOLOGY AND PATHOLOGY Histology of Colonic Polyps Location of Adenomas Adenoma-Carcinoma Sequence Advanced Adenoma Multiple Adenomas SCREENING Theory of Screening and Cost-Benefit Analysis Screening Modalities Fecal Occult Blood Test and Other Stool-Based Examinations Theory Benefit Limitations Recommendation Flexible Sigmoidoscopy Theory Benefits Limitations Recommendation Double-Contrast Barium Enema Theory Benefits Limitations Recommendation Colonoscopy Theory Benefits Limitations Recommendation CT Colonography Theory Benefits Limitations Recommendation Recommendation IMAGING Early-Stage Adenocarcinoma and the Adenomatous Polyp The Diminutive Lesion (