Lesson 1Indications and timing for follow-up imaging and use of ultrasound or MRI in equivocal or pregnant patientsThis section reviews when to repeat imaging, how clinical evolution guides modality choice, and the roles of ultrasound and MRI in equivocal, pediatric, and pregnant patients while balancing diagnostic yield, radiation, and contrast safety.
Clinical triggers for repeat imagingUltrasound technique in suspected appendicitisMRI protocols in pregnancy and pediatricsBalancing 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 with antibiotic and perioperative planning, including contamination extent, abscess burden, and sepsis risk, and discusses timing of surgery, prophylaxis choices, and duration of therapy based on radiologic 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, localized 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 discusses how to recognize subtle signs that alter urgency and type of intervention.
Direct and indirect signs of perforationDistinguishing phlegmon from abscessDetection of free intraperitoneal airSmall-bowel obstruction related to appendicitisPredictors of postoperative complicationsLesson 4Measurement and characterization of periappendiceal abscesses: size, loculation, gas, and adjacent bowel involvementThis section explains how to measure and characterize periappendiceal abscesses on CT, including size, loculation, gas content, and adjacent bowel involvement, and how these features guide drainage feasibility, access route, and urgency.
Standardized 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, covering IV contrast timing, oral contrast indications, phase selection, and low-dose strategies that preserve diagnostic quality while minimizing radiation and contrast-related 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, emphasizing key required elements, severity grading, clear impression statements, and actionable recommendations that support timely, appropriate management.
Essential elements of the CT reportStandardized 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 influence selection of antibiotics alone, percutaneous drainage, or surgery, emphasizing abscess size, sepsis, comorbidities, and multidisciplinary discussion between radiology, surgery, and interventional radiology 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, and explains measurement techniques and pitfalls that can mimic or obscure disease.
Measuring appendiceal diameter accuratelyAssessing wall thickening and enhancementCharacterizing periappendiceal fat strandingLuminal obstruction, fecalith, and fluidCommon pitfalls and normal variantsLesson 9CT anatomy of the right lower quadrant: appendix variants, cecum, terminal ileum, mesoappendix, and adjacent structuresThis section reviews right lower quadrant anatomy on CT, including cecum, terminal ileum, mesoappendix, and vascular landmarks, and highlights common appendix positions and variants that affect detection, interpretation, and potential surgical planning.
Identifying the cecum and ileocecal valveLocating the normal appendix on CTRetrocecal 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 that distinguish appendicitis from key mimics, including terminal ileitis, Crohn disease, Meckel diverticulitis, epiploic appendagitis, and right-sided diverticulitis, emphasizing wall pattern, location, and fat changes.
Terminal ileitis versus appendicitis on CTCrohn disease activity in the right lower quadrantCT signs of Meckel diverticulitisRecognizing epiploic appendagitisRight-sided colonic diverticulitis features
