Sepsis CT
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American Roentgen Ray Society Images of Sepsis CT |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Priyamvada Singh, M.B.B.S. [2] Jason Le, B.S.[3]
Synonyms and keywords: sepsis syndrome; septic shock; septicemia
Sepsis CT
Computed tomography (CT) has no imaging pattern specific for sepsis. Its principal role is to identify an anatomic source of infection when no source is clinically apparent or when first-line evaluation is normal or equivocal, characterize complications of a suspected source, and facilitate source control through image-guided drainage or surgical planning.[1] Septic foci are most commonly identified in the chest, abdomen, and pelvis.[1]
The 2024 American College of Radiology Appropriateness Criteria support contrast-enhanced CT (CECT) of the relevant body region when the source is undifferentiated or initial evaluation is nondiagnostic. In patients without localizing features, CT of the chest, abdomen, and pelvis with intravenous contrast is an appropriate strategy.[1]
Diagnostic performance and yield
CT is primarily a rule-in rather than rule-out test for an infectious focus in suspected sepsis.
- In an emergency-department cohort summarized in the 2024 ACR criteria, CT performed within 72 hours identified a septic focus in 76.5% of scans, with a positive predictive value (PPV) of 81.8% (95% CI 76.3%-86.3%) but a negative predictive value (NPV) of only 21.7% (95% CI 10.7%-39.1%). The chest was the most common focus (38.6%), followed by the abdomen (22.0%) and pelvis/genitourinary tract (20.5%).[1]
- In a separate Sepsis-3-based emergency-department cohort, CT identified the final septic source in 69.4%, with sensitivity of 81.1% (95% CI 68.0%-90.6%) and specificity of 55.6% (95% CI 21.2%-86.3%). The authors concluded that CT should be used to identify a focus when clinically indicated, but not as a rule-out test.[2]
- In medical-ICU patients with sepsis, body CT detected septic foci with a PPV of 90.6% (95% CI 86%-95.2%) but an NPV of only 32.4% (95% CI 21%-43.8%), reinforcing that CT is a rule-in rather than a rule-out test. A negative study does not exclude an occult focus that may become apparent later in the hospital course.[3]
- In surgical ICU patients scanned for suspected infection, a source was identified in 52.8% and CT changed management in 45%, including antimicrobial changes, surgery, or drainage-catheter placement.[1]
- In patients with sepsis of unknown origin undergoing abdominal CT, 63.8% had positive findings; common findings included liver abscess, acute pyelonephritis, and cholangitis. Leukocytosis, anemia, elevated absolute neutrophil count, and positive blood cultures were associated with positive scans, supporting selective rather than indiscriminate abdominal CT.[4]
Source-specific CT findings
- Thoracic: consolidation, necrotizing pneumonia or cavitation, lung abscess, empyema (including pleural fluid with a split-pleura sign), and mediastinitis. CT can detect pneumonia and complications that may be missed or incompletely characterized on chest radiography.[1]
- Abdominopelvic: intra-abdominal or pelvic abscess, secondary peritonitis/free air, acute cholecystitis and cholangitis, appendicitis, diverticulitis, bowel ischemia or perforation, and pancreatic necrosis.[1][5][6] For appendicitis, CT sensitivity is approximately 91%-96% and specificity approximately 90%-94%.[5][6]
- Genitourinary: obstructing or infected urolithiasis, acute pyelonephritis (including wedge-shaped hypoenhancement), emphysematous infection, and renal or perinephric abscess.[4]
- Vascular, device-associated, and deep-space infection: infected fluid collections and selected deep infections such as spinal epidural abscess, discitis, and prosthetic or line-associated infection.
ARDS on CT
Acute respiratory distress syndrome (ARDS) is a common complication of severe infection and sepsis. CT can demonstrate the bilateral pulmonary opacities used in the ARDS imaging criterion and, compared with plain radiography, better characterizes their distribution and heterogeneity.[7][8]
A characteristic CT pattern in the acute phase is heterogeneous, gravitationally dependent alveolar consolidation with relative anterior sparing. CT may also demonstrate interlobular septal thickening, pleural effusions, and other findings that help characterize the pulmonary process and distinguish ARDS from competing diagnoses.[7][9]
Contrast, timing, and safety
- IV contrast: Intravenous contrast materially increases the spectrum of detectable pathology and is recommended for abdominopelvic and most thoracic sepsis imaging unless contraindicated.[1]
- Kidney disease and contrast: Acute kidney injury is common in sepsis, but the risk of acute kidney injury attributable to intravenous iodinated contrast has been overstated. Concern for contrast-associated acute kidney injury should not withhold clinically indicated CECT when CT is likely to identify a source amenable to source control. Propensity-matched cohorts have found no independent association between contrast administration and acute kidney injury in septic patients, including patients with sepsis-associated acute kidney injury (stages 2-3).[10][11][12]
- Saline prophylaxis: For patients with AKI or an eGFR <30 mL/min/1.73 m² who are not receiving maintenance dialysis, intravenous normal-saline prophylaxis is indicated when iodinated contrast is administered.[10]
- Timing: European emergency-radiology and interdisciplinary surveys favor CECT within approximately 1-6 hours of sepsis diagnosis in selected patients, particularly with decreased vigilance, rising vasopressor requirement, or elevated lactate/procalcitonin; however, observational data have not demonstrated an independent mortality benefit from earlier CT, and optimal timing remains uncertain.[13][14][2]
- Transport risk: CT requires transport of a potentially unstable patient. Hemodynamic and airway stability should be considered, and time-critical resuscitation, cultures, or antimicrobials should not be delayed to obtain imaging.[2]
Clinically actionable recommendations
- Obtain region-directed CECT when a source is suspected clinically but not confirmed, or when chest radiography, urinalysis, or ultrasound is normal or equivocal.[1][2]
- In sepsis without localizing features, consider CT of the chest, abdomen, and pelvis with IV contrast to survey common infectious foci.[1]
- Do not use a negative CT to exclude infection or an infectious focus. Its low NPV requires continued microbiologic evaluation and consideration of alternative or evolving sources.[2][3]
- Use CT findings to identify a drainable or otherwise controllable focus. Identification of such a focus is the principal management-altering benefit of CT and may lead to percutaneous drainage or surgery.[1]
- Do not delay resuscitation, blood cultures, or antibiotics to obtain CT in an unstable patient; stabilize the patient sufficiently for safe transport and imaging.[2]
High-yield clinical pearls
- A positive CT is highly informative; a negative CT is not — CT should not be used alone to exclude an infectious source.[2][3]
- The principal management value of CT is identification of a focus amenable to source control.[1]
- In patients with sepsis of unknown origin, selective abdominal CT may identify clinically important sources such as liver abscess, pyelonephritis, or cholangitis.[4]
- On chest CT, dependent posterior consolidation with relative anterior sparing is characteristic of the heterogeneous acute-phase pulmonary pattern seen in ARDS.[7]
Common pitfalls
- Using a negative CT to rule out infection or an occult infectious source.[2]
- Delaying antibiotics, cultures, or resuscitation to obtain imaging in an unstable patient.[2]
- Withholding IV contrast solely because of AKI concern when clinically indicated CECT is likely to identify a source amenable to source control, while failing to consider appropriate renal-risk prophylaxis.[10]
- Transporting a hemodynamically unstable patient to CT without adequate stabilization.[2]
- Ordering broad pan-CT reflexively rather than selecting region-directed CECT according to clinical and laboratory clues.[4]
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 Brixey AG, Fung A, De Leon AD; et al. (2024). "ACR Appropriateness Criteria® Sepsis". Journal of the American College of Radiology. 21 (6S): S292–S309. doi:10.1016/j.jacr.2024.02.029.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 Pohlan J, Möckel M, Slagman A; et al. (2024). "Computed Tomography in Patients With Sepsis Presenting to the Emergency Department: Exploring Its Role in Light of Patient Outcomes". European Radiology. 34 (10): 6466–6474. doi:10.1007/s00330-024-10701-y. PMID 38592420 Check
|pmid=value (help). - ↑ 3.0 3.1 3.2 Pohlan J, Witham D, Opper Hernando MI; et al. (2022). "Relevance of CT for the Detection of Septic Foci: Diagnostic Performance in a Retrospective Cohort of Medical Intensive Care Patients". Clinical Radiology. 77 (3): 203–209. doi:10.1016/j.crad.2021.10.020. PMID 34872706 Check
|pmid=value (help). - ↑ 4.0 4.1 4.2 4.3 Ho PH, Lee YC, Ng CJ, Chaou CH, Chen SY. (2024). "Assessing the Clinical Utility of Abdominal Computed Tomography in Sepsis Patients With Unknown Origin: A Retrospective Cohort Study". Medicine. 103 (20): e38114. doi:10.1097/MD.0000000000038114. PMID 38758906 Check
|pmid=value (help). - ↑ 5.0 5.1 Moris D, Paulson EK, Pappas TN. (2021). "Diagnosis and Management of Acute Appendicitis in Adults: A Review". JAMA. 326 (22): 2299–2311. doi:10.1001/jama.2021.20502.
- ↑ 6.0 6.1 Kambadakone AR, Santillan CS, Kim DH; et al. (2022). "ACR Appropriateness Criteria® Right Lower Quadrant Pain: 2022 Update". Journal of the American College of Radiology. 19 (11S): S445–S461. doi:10.1016/j.jacr.2022.09.011.
- ↑ 7.0 7.1 7.2 Meyer NJ, Gattinoni L, Calfee CS. (2021). "Acute Respiratory Distress Syndrome". The Lancet. 398 (10300): 622–637. doi:10.1016/S0140-6736(21)00439-6. PMID 34217425 Check
|pmid=value (help). - ↑ Thompson BT, Chambers RC, Liu KD. (2017). "Acute Respiratory Distress Syndrome". The New England Journal of Medicine. 377 (6): 562–572. doi:10.1056/NEJMra1608077.
- ↑ Ware LB, Matthay MA. (2000). "The Acute Respiratory Distress Syndrome". The New England Journal of Medicine. 342 (18): 1334–1349. doi:10.1056/NEJM200005043421806.
- ↑ 10.0 10.1 10.2 Davenport MS, Perazella MA, Yee J; et al. (2020). "Use of Intravenous Iodinated Contrast Media in Patients With Kidney Disease: Consensus Statements From the ACR and the National Kidney Foundation". Radiology. 294 (3): 660–668. doi:10.1148/radiol.2019192094. PMID 31961246.
- ↑ Hinson JS, Al Jalbout N, Ehmann MR, Klein EY. (2019). "Acute Kidney Injury Following Contrast Media Administration in the Septic Patient: A Retrospective Propensity-Matched Analysis". Journal of Critical Care. 51: 111–116. doi:10.1016/j.jcrc.2019.02.003. PMID 30798098.
- ↑ Goto Y, Koyama K, Katayama S; et al. (2019). "Influence of contrast media on renal function and outcomes in patients with sepsis-associated acute kidney injury: a propensity-matched cohort study". Critical Care. 23 (1): 249. doi:10.1186/s13054-019-2517-3.
- ↑ Stahl AC, Rubarth K, Opper Hernando MI; et al. (2026). "Contrast-Enhanced CT in Sepsis: Insights From a European Emergency Radiology Survey". European Radiology. 36 (7): 5987–5995. doi:10.1007/s00330-025-12256-y. PMID 41586846 Check
|pmid=value (help). - ↑ Opper Hernando MI, Witham D, Steinhagen PR; et al. (2023). "Interdisciplinary Perspectives on Computed Tomography in Sepsis: Survey Among Medical Doctors at a Large University Medical Center". European Radiology. 33 (12): 9296–9308. doi:10.1007/s00330-023-09842-3. PMID 37450054 Check
|pmid=value (help).