CT Diverticulitis (CT Abd/Pel) — Dictation, Appropriateness, and Dose for Residents
1. The Stat Diverticulitis CT: Hinchey Class Now, Please
It’s a classic Tuesday afternoon. You get a stat CT from the emergency department: a 68-year-old with sharp left lower quadrant pain, fever, and a white count of 17. The ED attending is sure it’s diverticulitis and wants to know if there’s an abscess to drain. Your body imaging attending is going to expect a definitive Hinchey classification in the impression, a clear statement on complications like perforation or fistula, and a recommendation for follow-up colonoscopy to rule out a mimic.
When I was a PGY-2 on call, I’d sometimes just describe the fat stranding and wall thickening and move on. But getting crisp on the classification and potential mimics is what separates a resident report from an attending-level one. This guide is built to get you there faster, with a solid template and the key clinical pearls that matter. For more tools like this, check out our free residents and fellows resource hub.
2. What a CT Abdomen and Pelvis for Suspected Diverticulitis Covers and What Attendings Look For
This is a workhorse study. The goal is to rapidly confirm or exclude acute diverticulitis and, more importantly, to stage its severity and identify complications that change management from medical therapy to percutaneous drainage or emergent surgery.
Common indications include acute left lower quadrant (LLQ) pain, suspected diverticular abscess, or evaluation for complications like a colovesical fistula. While sigmoid diverticulitis is most common, remember that right-sided diverticulitis can occur (especially in patients of East Asian descent) and can clinically mimic appendicitis.
Your attending expects a report that systematically answers:
- Is acute diverticulitis present? Look for the classic triad: bowel wall thickening, pericolic fat stranding, and the presence of diverticula.
- What is the severity? Use the Hinchey classification to communicate this clearly in the impression.
- Are there complications? Systematically hunt for abscess, contained or free perforation (free air), fistula formation (e.g., air in the bladder), and signs of obstruction.
- Is there a concerning mimic? Colon cancer can present with focal wall thickening and stranding. For a first episode in an older patient, recommending follow-up colonoscopy after the acute inflammation resolves (typically 6 weeks) is standard practice.
- Are there ominous signs? Don’t miss the late, dangerous findings like pneumatosis or portal venous gas.
3. Radiology Report Template for CT Abdomen and Pelvis for Suspected Diverticulitis
Use this template as a starting point for your macros. It’s structured to ensure you hit all the key points your attending and the clinical team need.
Technique
CT of the abdomen and pelvis was performed with intravenous contrast following a portal venous phase protocol. Axial images were reviewed, with multiplanar reformations provided.
Findings
COMPARISON: [Date of prior study]
LUNGS: Visualized lung bases are clear.
LIVER, GALLBLADDER, BILIARY TREE, SPLEEN, PANCREAS, ADRENALS, KIDNEYS: Unremarkable.
COLON: The primary site of inflammation is in the [sigmoid colon, descending colon]. There is [mild, moderate, severe] concentric wall thickening and mucosal hyperenhancement. Extensive surrounding pericolic fat stranding is present. Multiple diverticula are noted in this segment.
- Abscess: [There is no evidence of a drainable fluid collection or abscess. / There is a [size] cm rim-enhancing fluid collection located [e.g., adjacent to the sigmoid colon in the left paracolic gutter], consistent with a pericolic abscess.]
- Perforation: [There is no extraluminal air to suggest perforation. / There are locules of extraluminal air contained within the pericolic fat, consistent with a contained perforation. / There is pneumoperitoneum, consistent with free perforation.]
- Fistula: [No evidence of colovesical or colovaginal fistula. / There is air within the urinary bladder, concerning for a colovesical fistula.]
The remainder of the colon is unremarkable. The appendix is normal in appearance. The terminal ileum is unremarkable.
OTHER: [Other findings, e.g., vasculature, lymph nodes, osseous structures].
Impression
1. Findings consistent with acute diverticulitis involving the [sigmoid colon].
2. [No evidence of abscess or perforation. (Modified Hinchey Classification Stage Ia)] OR [A [size] cm pericolic abscess is present. (Modified Hinchey Classification Stage Ib)] OR [Distant pelvic abscess measuring [size] cm. (Modified Hinchey Classification Stage II)] OR [Evidence of generalized purulent/fecal peritonitis. (Modified Hinchey Classification Stage III/IV)].
3. RECOMMENDATION: For a first episode of diverticulitis, follow-up colonoscopy in approximately 6 weeks is recommended after resolution of the acute inflammatory process to exclude an underlying malignancy.
4. Free Template Sources from the Radiology Community
Building your own template library is a rite of passage. But you don’t have to start from scratch. Two great free repositories exist that are curated by radiologists and are worth bookmarking:
- RadReport.org: Maintained by the RSNA, this is a comprehensive library of peer-reviewed templates covering nearly every modality and subspecialty.
- Radiology Templates (AU): An excellent, user-friendly site run by Australian radiologists with practical, clean templates for daily use.
Both are great resources for seeing how others structure complex reports.
5. The Next-Level Move: Free-Form Dictation to Structured Report
A solid macro is a great start, but the real world is messy. You spot an unexpected finding, and now you’re jumping around your template, trying to slot it in. This is where AI-assisted reporting tools can streamline your workflow.
Instead of meticulously navigating a template, you can dictate your positive findings in free form—”thickened sigmoid colon with extensive fat stranding and a 3 cm pericolic abscess”—and let the software handle the rest. GigHz Precision AI is designed to take that free-form dictation and generate a clean, structured report based on pre-loaded ACR and SIR templates. It helps ensure all the critical elements, like the Hinchey classification, are included in the impression. While no specific Clinical Decision Support (CDS) popup fires for this particular template, the system is built to surface relevant CDS for other studies (like LI-RADS or Bosniak classifications) automatically, helping you apply the right criteria without breaking your concentration.
6. When Should You Order a CT Abdomen and Pelvis for Suspected Diverticulitis? ACR Appropriateness Criteria
The American College of Radiology (ACR) provides evidence-based guidelines that are the bedrock of our practice. For a patient presenting with left lower quadrant pain, the guidance is quite clear.
According to the ACR Appropriateness Criteria for Left Lower Quadrant Pain, a CT of the abdomen and pelvis with IV contrast is rated **Usually Appropriate** for the initial imaging of a patient with suspected diverticulitis. This holds true whether it’s a general presentation of LLQ pain or if there’s a specific concern for complications. The study provides the most comprehensive evaluation for both the primary inflammatory process and the potential for abscess, perforation, or fistula that would require a change in management.
Alternatives like MRI may be considered in pregnant patients to avoid radiation, but CT remains the first-line modality for most adults due to its speed, availability, and high diagnostic accuracy. Colonoscopy is not used in the acute setting due to the risk of perforation but is critical for follow-up to exclude malignancy.
7. How Much Radiation Does a CT Abdomen and Pelvis for Diverticulitis Deliver?
Patients and referring providers often ask about radiation dose. Being able to contextualize it is a key part of our job. A standard portal-venous phase CT of the abdomen and pelvis for suspected diverticulitis delivers an estimated effective dose of **6-10 mSv**.
This dose is comparable to several months to a few years of natural background radiation that we all receive just by living on Earth. While we always adhere to the ALARA (As Low As Reasonably Achievable) principle, this level of exposure is considered appropriate and justified given the critical clinical questions the study answers, especially when evaluating for life-threatening complications like perforation or a large abscess.
| Exposure Source | Estimated Effective Dose |
|---|---|
| Natural Background Radiation (1 year) | ~3 mSv |
| CT Abdomen/Pelvis (Diverticulitis Protocol) | 6-10 mSv |
| Chest X-ray (PA/LAT) | ~0.1 mSv |
Dose reduction techniques are built into modern scanner protocols, but the diagnostic quality needed to spot subtle wall thickening or a small abscess requires a standard-dose protocol.
8. CT Abdomen and Pelvis for Diverticulitis Imaging Protocol — Phases, Contrast, and Reconstructions
A robust, consistent protocol is essential for diagnostic accuracy. The standard for a suspected diverticulitis scan is a single portal-venous phase acquisition, which provides excellent enhancement of the bowel wall and solid organs, making inflammatory changes and abscess collections conspicuous.
The protocol is nearly identical to that used for suspected appendicitis, optimized for detecting acute inflammatory processes in the abdomen and pelvis.
| Phase / Reconstruction | Contrast | Delay | Slice Thickness | Coverage |
|---|---|---|---|---|
| Topogram | None | N/A | N/A | Diaphragm to Pubic Symphysis |
| Portal Venous Helical | IV (100-125 mL @ 3-4 mL/s) | 60-70 seconds | 3-5 mm | Diaphragm to Pubic Symphysis |
| Soft Tissue Recons | N/A | N/A | 3-5 mm (Axial) | Full Volume |
| Thin Recons (for MPRs) | N/A | N/A | 1-1.5 mm (Axial) | Full Volume |
Common protocol pitfalls:
- Oral Contrast: The use of oral contrast is institution-dependent and has largely fallen out of favor for this indication. IV contrast alone is typically sufficient and allows for a much faster study, which is critical in the emergency setting.
- Skipping Thin Recons: Don’t skip the 1-1.5 mm thin reconstructions. They are essential for creating high-quality sagittal and coronal multiplanar reformations (MPRs), which are invaluable for detecting subtle wall thickening, microperforations, and the relationship of an abscess to adjacent structures.
7. The 3-Months-Free Residents Offer
3+ months free for radiology residents and fellows
Look like a rockstar on your reports. With the GigHz Radiology Report Assistant, you can dictate your positive findings in free form, and our AI generates a perfectly structured report using ACR and SIR templates, firing the appropriate clinical decision support automatically. You focus on the images; we’ll handle the formatting.
All we ask is your feedback so we can keep improving the product for trainees. The signup is simple—no credit card, no long forms. Just provide the following three items:
- Your PGY year (e.g., PGY-2, PGY-4)
- Your training type (radiology residency or fellowship specialty)
- Your training program / hospital name
Ready to give it a try? Apply for the residents free-access program and we’ll get you set up.
8. Frequently Asked Questions
Is it HIPAA-compliant?
Yes. The platform is designed for de-identified workflows by default. It operates on the text of your report, not on patient-identifiable images or metadata from the PACS. No PHI leaves your institution’s environment.
Do I need my hospital’s IT department to set this up?
No. GigHz Precision AI is a secure, browser-based tool. There is no software to install. It works on any computer, including the call-room PC or your personal laptop/iPad.
Does it work with PowerScribe or other dictation systems?
Yes. It works alongside any dictation system. You dictate as you normally would, and the tool assists with structuring and applying the correct reporting frameworks. You can then copy-paste the final, structured impression back into your RIS/PACS.
Can I use this on my phone or iPad?
Absolutely. The platform is fully responsive and designed to work on mobile devices, making it a useful tool for reviewing report structure or checking a classification system on the go.
Can I customize the templates?
Yes. While the system comes pre-loaded with standard ACR and society-level templates, you can create, modify, and save your own templates and macros to match your personal preferences or your institution’s required format.
What happens after my residency or fellowship ends?
Trainee accounts transition to a standard plan after graduation. We offer discounts for early-career radiologists who wish to continue using the platform in their practice.
Free GigHz Tools That Pair With This Article
Three free tools that complement the material above:
- ACR Appropriateness Criteria Lookup — Type an indication or clinical scenario in plain language and get the imaging studies the ACR rates for it, with adult and pediatric radiation levels. Built directly from 297 ACR topics, 1,336 clinical variants, and 15,823 procedure ratings.
- GigHz Imaging Protocol Library — A searchable library of 131 imaging protocols with the physics specs surfaced and the matching ACR Appropriateness Criteria alongside. Plain-English narratives readable in 60 seconds, organized by modality.
- GigHz Radiation Dose Calculator — Pick the imaging studies a patient has had and see total dose in millisieverts (mSv) with comparisons to natural background radiation, transatlantic flights, and chest X-rays. Useful for shared decision-making.
Reviewed by Pouyan Golshani, MD, Interventional Radiologist — May 7, 2026
