Lesson 1Indications and timing for follow-up imaging and use of ultrasound or MRI in equivocal or pregnant patientsThis section reviews indications for repeat imaging, how clinical progression influences modality choice, and the roles of ultrasound and MRI in equivocal, paediatric, and pregnant patients, balancing diagnostic value, radiation, and contrast safety.
Clinical triggers for repeat imagingUltrasound technique in suspected appendicitisMRI protocols in pregnancy and paediatricsBalancing radiation risk and diagnostic yieldWhen CT remains necessary in pregnancyLesson 2Antibiotic and perioperative considerations tied to imaging findings (e.g., extent of contamination, abscess)This section links CT findings to antibiotic and perioperative planning, covering contamination extent, abscess burden, and sepsis risk, including surgery timing, prophylaxis options, and therapy duration based on radiological severity.
Imaging predictors of severe contaminationAbscess burden and antibiotic spectrumTiming of surgery after source controlCT guidance for postoperative prophylaxisImaging clues to resistant or atypical infectionLesson 3CT features of complicated appendicitis: perforation, phlegmon, localised abscess, free intraperitoneal air, and small-bowel obstructionThis section reviews CT features of complicated appendicitis, including perforation, phlegmon, abscess, free air, and small-bowel obstruction, and how to spot subtle signs affecting intervention urgency and type.
Direct and indirect signs of perforationDistinguishing phlegmon from abscessDetection of free intraperitoneal airSmall-bowel obstruction related to appendicitisPredictors of postoperative complicationsLesson 4Measurement and characterisation of periappendiceal abscesses: size, loculation, gas, and adjacent bowel involvementThis section explains measuring and characterising periappendiceal abscesses on CT, including size, loculation, gas content, and adjacent bowel involvement, and how these inform drainage feasibility, access route, and urgency.
Standardised abscess size measurementsLoculation, septations, and complexityGas patterns and fistula suspicionAdjacent bowel and organ involvementSelecting candidates for percutaneous drainageLesson 5Contrast-enhanced CT protocols for acute abdomen: oral/IV contrast considerations, phases, and low-dose techniquesThis section details contrast-enhanced CT protocols for acute abdomen, including IV contrast timing, oral contrast indications, phase selection, and low-dose methods that maintain diagnostic quality whilst reducing radiation and contrast risks.
IV contrast timing and injection parametersRole of oral contrast in suspected appendicitisSingle versus multiphasic acquisition choicesLow-dose and iterative reconstruction methodsManaging contrast allergy and renal riskLesson 6Reporting format for abdominal CT in acute appendicitis: concise findings, severity grading, and recommended next stepsThis section outlines a structured CT reporting approach for suspected appendicitis, highlighting essential elements, severity grading, clear impressions, and actionable recommendations for timely management.
Essential elements of the CT reportStandardised severity grading systemsClear impression and diagnostic certaintyActionable management recommendationsCommunicating critical and unexpected findingsLesson 7Interventional radiology and surgical decision-making: indications for percutaneous drainage vs. appendectomy vs. antibiotics-first strategiesThis section explains how CT findings guide choices between antibiotics alone, percutaneous drainage, or surgery, considering abscess size, sepsis, comorbidities, and multidisciplinary input from radiology, surgery, and interventional teams.
CT criteria for antibiotics-first therapyIndications for percutaneous abscess drainageWhen urgent appendectomy is preferredImaging predictors of treatment failurePost-procedure imaging and complication checksLesson 8Primary CT findings of acute appendicitis: appendiceal diameter, wall thickening/enhancement, periappendiceal fat strandingThis section describes primary CT signs of acute appendicitis, including appendiceal diameter, wall thickening, mural enhancement, and periappendiceal fat stranding, with measurement techniques and pitfalls that may mimic or obscure the condition.
Measuring appendiceal diameter accuratelyAssessing wall thickening and enhancementCharacterising periappendiceal fat strandingLuminal obstruction, faecalith, and fluidCommon pitfalls and normal variantsLesson 9CT anatomy of the right lower quadrant: appendix variants, caecum, terminal ileum, mesoappendix, and adjacent structuresThis section reviews right lower quadrant anatomy on CT, including caecum, terminal ileum, mesoappendix, and vascular landmarks, highlighting common appendix positions and variants that influence detection, interpretation, and surgical planning.
Identifying the caecum and ileocaecal valveLocating the normal appendix on CTRetrocaecal and pelvic appendix positionsMesoappendix, vessels, and lymph nodesCongenital and postsurgical anatomic variantsLesson 10Differentiating appendicitis from mimics: terminal ileitis, Meckel diverticulitis, Crohn disease, epiploic appendagitis, right-sided diverticulitisThis section focuses on CT features distinguishing appendicitis from mimics like terminal ileitis, Crohn disease, Meckel diverticulitis, epiploic appendagitis, and right-sided diverticulitis, emphasising wall patterns, location, and fat changes.
Terminal ileitis versus appendicitis on CTCrohn disease activity in the right lower quadrantCT signs of Meckel diverticulitisRecognising epiploic appendagitisRight-sided colonic diverticulitis features
