CT Triphasic Liver (HCC Protocol) — Dictation, Appropriateness, and Dose for Residents

1. The High-Stakes Read: Getting LI-RADS Right

Outpatient multiphase CT liver. Known cirrhosis. There’s a new 2.2 cm observation in segment 8 showing arterial phase hyperenhancement. The interventional radiology attending wants a definitive LI-RADS category in the impression, and you know LR-5 means the patient can go straight to treatment without a biopsy. No pressure.

When I was a PGY-3 on body call, I’d sometimes punt on the full LI-RADS classification for a late-night read, hoping to circle back in the morning. Sometimes that worked. Sometimes the attending caught it on the prelim and wanted to know why I hadn’t committed to an LR-4 or LR-5. The triphasic liver protocol is one of those studies where precision matters immensely, because your read directly impacts management. This guide is built to make those reads faster, more confident, and more accurate. For more high-yield guides like this, check out the residents and fellows resource hub.

2. What a CT Triphasic Liver for Hepatocellular Carcinoma Covers and What Attendings Look For

The entire purpose of a triphasic (or quadriphasic) liver CT is to exploit the unique blood supply of Hepatocellular Carcinoma (HCC). HCC is typically fed by the hepatic artery, causing it to light up brightly on the arterial phase—arterial phase hyperenhancement (APHE)—and then wash out relative to the surrounding liver parenchyma, which gets its blood supply primarily from the portal vein. This protocol is specifically timed to capture that dynamic enhancement pattern, allowing for classification using the Liver Imaging Reporting and Data System (LI-RADS).

In a patient with cirrhosis or other risk factors for HCC, this study is designed to answer several key questions:

• LI-RADS Classification: Can we confidently categorize each liver observation from LR-1 (definitely benign) to LR-5 (definitely HCC)?
• Definitive Diagnosis: Does an observation meet criteria for LR-5? In a cirrhotic patient, this is equivalent to a biopsy-proven HCC and the patient can proceed to treatment.
• Tumor Staging: Is there evidence of tumor in vein (LR-TIV), a critical finding for staging and treatment planning? What is the extent of disease?
• Treatment Response: For patients who have undergone therapy like TACE or ablation, how has the tumor responded? (This uses the separate LR-TR algorithm).

Your attending expects a systematic evaluation of every observation, with a final LI-RADS category assigned in the impression for any suspicious lesion.

3. Radiology Report Template for CT Triphasic Liver (Hepatocellular Carcinoma / LI-RADS Protocol)

This template provides a solid foundation. Remember to tailor the findings to the specific case.

Technique

Multi-phase CT of the abdomen was performed with and without intravenous contrast. Scans were obtained in pre-contrast, late arterial, portal venous, and delayed phases following the administration of [##] mL of [Contrast Agent].

Findings

LIVER: The liver contour is [smooth/nodular], consistent with [underlying cirrhosis/chronic liver disease]. No diffuse steatosis. No intra- or extrahepatic biliary ductal dilatation.

LIVER OBSERVATIONS (LI-RADS):

[Describe each observation systematically. Use a new paragraph for each.]

Observation #1: Segment [##]
Size: [## x ##] cm.
Enhancement Pattern: [Describe enhancement on each phase, e.g., “Demonstrates arterial phase hyperenhancement with subsequent non-peripheral washout on the portal venous phase.”]
Ancillary Features: [e.g., “Enhancing capsule is present on the delayed phase.” “No threshold growth compared to prior study dated YYYY-MM-DD.”]
LI-RADS Category: LR-[##]

PORTAL VEIN: The main, right, and left portal veins are patent. [No evidence of enhancing tumor thrombus. / There is enhancing soft tissue distending the [e.g., right portal vein], consistent with tumor in vein (LR-TIV).]

OTHER ORGANS:
Gallbladder: Unremarkable.
Spleen: [Normal size / Splenomegaly, measuring ## cm].
Pancreas: Unremarkable.
Adrenal Glands: Unremarkable.
Kidneys: No hydronephrosis or suspicious renal mass.
Bowel and Mesentery: No bowel obstruction or inflammatory change.
Vasculature: Aorta is normal in caliber. No signs of dissection.
Bones: No aggressive osseous lesion.
Other: [e.g., Ascites, varices, etc.]

Impression

1. Nodular liver contour consistent with cirrhosis.

2. Liver observations classified per LI-RADS v2018:

• Segment [##]: [##] cm observation with arterial phase hyperenhancement and [washout/enhancing capsule], categorized as LI-RADS 5 (Definitely HCC).
• Segment [##]: [##] cm observation with [features], categorized as LI-RADS 4 (Probably HCC).
• [If present] Enhancing tumor thrombus within the [e.g., right portal vein], categorized as LI-RADS TIV (Tumor in Vein).

3. [Other significant findings, e.g., Splenomegaly and portosystemic collateral vessels consistent with portal hypertension.]

Key Principles for a Solid LI-RADS Read:

• Late Arterial is Key: This is the money phase. You need to see the portal vein enhanced but the hepatic veins NOT yet enhanced. This timing captures HCC’s APHE.
• Washout is Non-Peripheral: True washout is hypoenhancement of the lesion’s core on portal venous or delayed phases compared to the background liver. Don’t confuse it with peripheral enhancement.
• Capsule vs. Rim Enhancement: An “enhancing capsule” is a smooth, uniform rim of enhancement on the portal venous or delayed phase. It’s a major feature for HCC. Don’t confuse it with “rim APHE,” which is an ancillary feature favoring malignancy but not specific for HCC.
• Always Hunt for LR-TIV: Tumor in vein is a game-changer for staging and prognosis. Scrutinize the portal and hepatic veins for any enhancing, expansile filling defect.
• Mind the Dose: This is a high-radiation study. That’s why MRI is preferred for routine surveillance when possible.

4. Free Template Sources for Your Library

Building a personal macro library is a rite of passage. If you’re looking for more templates beyond this one, two great free repositories exist, curated by radiologists for radiologists. They are excellent sources for building out your toolkit.

• RadReport.org: Maintained by the RSNA, this is a comprehensive library of peer-reviewed templates covering nearly every modality and subspecialty.
• Radiology Templates (AU): A fantastic, well-organized library from Australia with clean, practical templates for daily use.

5. The Next-Level Move: Free-Form Dictation to Structured Report

The template above is static. You still have to manually slot in your findings, measurements, and LI-RADS categories. The next step in workflow is letting AI handle the structuring. Instead of clicking through a structured report or editing a macro, you can simply dictate your positive findings in free form.

For example, you’d dictate: “There is a 2.5 cm lesion in segment 7 with arterial hyperenhancement and non-peripheral washout on the portal venous phase. I also see an enhancing capsule on the delayed phase. This is an LR-5.”

Tools like GigHz Precision AI are designed to parse that natural language and automatically generate a clean, structured report using pre-loaded ACR and SIR templates. It helps ensure all the key features are documented correctly and consistently, which makes your reports clearer and your attendings happier. It’s about reducing the manual work of formatting so you can focus on the diagnostic task.

6. When Should You Order a CT Triphasic Liver for Hepatocellular Carcinoma? ACR Appropriateness Criteria

The American College of Radiology (ACR) provides evidence-based guidelines for imaging. For liver lesions, the choice between CT and MRI often depends on the clinical context, patient factors, and institutional availability.

Per the ACR Appropriateness Criteria for Liver Lesion-Initial Characterization, multiphase CT is a viable option, though MRI is often preferred. For an incidental liver lesion greater than 1 cm found on ultrasound or single-phase CT in a patient with known chronic liver disease, multiphase CT or MRI are both rated “Usually Appropriate.” The same applies to smaller lesions less than 1 cm in this at-risk population.

In patients with a known extrahepatic malignancy, multiphase CT and MRI are again both “Usually Appropriate” for characterizing liver lesions of any size to differentiate metastases from benign findings. For patients with a normal liver and no suspicion of malignancy, MRI is generally favored over CT for initial characterization.

For the topic of Staging and Follow-up of Primary Liver Cancer, the guidelines are more direct. Multiphase liver CT is rated “Usually Appropriate” for the initial staging of HCC and for post-treatment evaluation after liver-directed therapy. For screening and active surveillance, MRI is typically preferred due to its higher sensitivity and lack of ionizing radiation, but CT remains a key alternative when MRI is contraindicated or unavailable.

7. How Much Radiation Does a CT Triphasic Liver Protocol Deliver?

A multiphase liver CT is a significant source of medical radiation. Because it involves scanning the liver up to four times (pre-contrast, arterial, portal venous, and delayed), the cumulative dose is substantial.

The estimated effective dose for a CT Triphasic Liver protocol is typically in the range of 15-30 mSv. To put that in perspective, this is equivalent to several years of natural background radiation. This dose level underscores why MRI is the preferred modality for routine HCC surveillance in at-risk patients, as it avoids cumulative radiation exposure over a patient’s lifetime.

Dose reduction techniques, such as automated tube current modulation and lower kVp settings (e.g., 100 kVp for the arterial phase), are critical for keeping the dose as low as reasonably achievable while maintaining diagnostic image quality.

8. CT Triphasic Liver Imaging Protocol — Phases, Contrast, and Reconstructions

A successful LI-RADS study hinges on a technically sound protocol. The timing of the contrast bolus and scan phases must be precise to capture the hemodynamic signature of HCC. The protocol typically involves a pre-contrast scan followed by three post-contrast phases.

The key is a high contrast injection rate (4-5 mL/s) to ensure a tight, dense bolus for the arterial phase. Arterial phase timing is most reliably achieved using bolus tracking over the descending aorta with a fixed 15-second delay after the trigger threshold is met. This ensures acquisition in the late arterial phase, not the early arterial phase.

Common protocol pitfalls: The most common error is improper arterial phase timing. Scanning too early (early arterial phase) means the portal vein isn’t opacified, and you can’t properly assess APHE relative to the still-unenhanced liver parenchyma. Scanning too late misses the peak arterial enhancement. Another pitfall is a slow contrast injection rate, which results in a “soft” arterial phase that blurs the distinction between phases and makes LI-RADS features difficult to assess.

9. The 3-Months-Free Offer for Residents and Fellows

3+ months free for radiology residents and fellows

Look like a rockstar on your reports — dictate positive findings in free form, and the AI generates a structured report using ACR + SIR templates with the appropriate clinical decision support firing automatically. All we ask in return is feedback so we can keep improving the product for trainees.

Signup is simple. No credit card, no long forms. To get set up, just provide three items:

1. Your PGY year (e.g., PGY-2, PGY-4)
2. Your training type (radiology residency or specific fellowship — IR, body, MSK, neuro, peds, breast, nucs)
3. Your training program / hospital name

To get started, apply for the residents free-access program.

10. Frequently Asked Questions

Is it HIPAA-compliant?

Yes. The platform is designed for de-identified workflows. You dictate findings, not raw PHI. It operates securely to ensure patient privacy is protected.

Do I need my hospital’s IT department to set it up?

No. It’s a browser-based tool that works on any modern computer, including the call-room PC or your personal laptop or iPad. There’s no software to install on hospital machines, so you can get started without needing IT approval.

Does it work with PowerScribe or other dictation systems?

Yes, it works alongside your existing PACS and dictation system. You can dictate your findings naturally, use the tool to generate the structured report, and then copy-paste the final text into PowerScribe, Fluency, or whatever system your institution uses.

Can I use it on my phone or iPad?

Yes, the platform is web-based and responsive, so you can access it on a desktop, laptop, or tablet like an iPad, which is perfect for the reading room or on call.

Can I customize the templates?

Yes. While the system comes pre-loaded with standard ACR and society-based templates, you can customize them to match your institution’s or your personal preferences for wording and structure.

What happens after my residency or fellowship ends?

The free access is for trainees. After you graduate, you can transition to a standard plan for practicing radiologists. Your customized templates and settings will carry over with you.

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