CTA Pulmonary (PE Protocol) — Dictation, Appropriateness, and Dose for Residents

The On-Call CTA Pulmonary Embolism Read: A Template for Residents

Stat CT pulmonary angiogram from the ED. Hemodynamically borderline patient. Your attending wants the clot burden, the RV-to-LV ratio, and the recommended next-step language in the impression — and they want it now. This isn’t a subtle liver lesion you can circle back to; this is a life-or-death call that changes management in the next 30 minutes. As a resident, you know the anatomy, but getting the report structured perfectly under pressure is the real test. You need to be fast, accurate, and definitive. This guide is built for that moment, drawing from thousands of reads and designed to give you the structure you need. For more tools like this, check out the residents and fellows resource hub.

What a CT Angiogram for Pulmonary Embolism Covers and What Attendings Look For

A CTA Pulmonary Embolism (PE) protocol is a rapid helical scan timed precisely to opacify the pulmonary arteries. The goal is to answer a few critical questions, and your attending will expect every one of them addressed in your report:

• Is there an acute pulmonary embolus? This is the primary question. You need to look for filling defects in the main, lobar, segmental, and subsegmental pulmonary arteries. A saddle embolus is the classic “can’t miss” finding.
• Is there evidence of right heart strain? This is the most common resident miss and a crucial prognostic indicator. You must measure the right ventricle to left ventricle (RV/LV) ratio on the axial 4-chamber view. A ratio >0.9 suggests strain and may trigger an interventional radiology consult for catheter-directed therapy.
• Are there alternative causes for the patient’s symptoms? The patient came in with shortness of breath. If you don’t see a PE, your job isn’t done. Scrutinize the lung parenchyma for pneumonia, look for a pneumothorax, and check for pleural or pericardial effusions.
• Is there evidence of chronic disease? Look for signs of chronic thromboembolic pulmonary hypertension (CTEPH), such as eccentric, web-like filling defects, vessel calcification, or mosaic perfusion in the lungs. This is a different disease process that requires a different workup.

Your report needs to be a complete answer sheet for the clinical team, covering not just the presence or absence of a clot but the entire cardiopulmonary picture.

Radiology Report Template for CTA Pulmonary (PE Protocol)

This template is a solid starting point for your personal macros. It’s structured to ensure you don’t miss the key elements your attending and the clinical team are looking for.

Technique

CT angiography of the chest was performed following the intravenous administration of [VOLUME] mL of [CONTRAST AGENT] contrast material. Images were acquired in the pulmonary arterial phase. Axial, coronal, and sagittal reformatted images were reviewed. Radiation dose reduction techniques were utilized.

Findings

PULMONARY ARTERIES: The main, bilateral lobar, segmental, and subsegmental pulmonary arteries are assessed for filling defects.
[Negative: The main, lobar, segmental, and subsegmental pulmonary arteries are patent, without evidence of acute or chronic pulmonary embolism.]
[Positive: There is an acute filling defect consistent with pulmonary embolism located in the [LOCATION – e.g., saddle configuration in the main pulmonary artery bifurcation, extending into the right and left main pulmonary arteries; segmental branches of the right lower lobe].]

HEART AND PERICARDIUM: The cardiac chambers are assessed for size. The right ventricle to left ventricle (RV/LV) ratio is [MEASUREMENT, e.g., 0.8] which is within normal limits. [or, …is elevated at 1.2, suggestive of right heart strain.] No significant pericardial effusion.

LUNGS AND PLEURA: The lung parenchyma is clear. [or, Specify alternative findings like consolidation, ground-glass opacities, nodules, pneumothorax.] No significant pleural effusion.

MEDIASTINUM AND HILA: No mediastinal or hilar lymphadenopathy.

AORTA AND GREAT VESSELS: The thoracic aorta is normal in caliber. The superior vena cava is patent.

CHEST WALL AND SKELETAL STRUCTURES: No acute fracture or destructive osseous lesion.

UPPER ABDOMEN: Limited evaluation of the upper abdomen reveals [e.g., no acute abnormality; incidental adrenal adenoma].

Impression

[Example 1: Negative for PE]
1. No evidence of acute or chronic pulmonary embolism.
2. Normal RV/LV ratio, without CT evidence of right heart strain.
3. No acute cardiopulmonary process to explain the patient’s symptoms.

[Example 2: Positive for PE with Strain]
1. Acute pulmonary embolism, as described above, with clot burden involving [e.g., the right main and bilateral lower lobe segmental pulmonary arteries].
2. Elevated RV/LV ratio of [e.g., 1.3], concerning for right heart strain.
3. No pneumonia or pneumothorax.

Where to Find Other Free Radiology Report Templates

Building a personal library of templates is a key part of residency. While you’ll get many from your own institution, two great free repositories exist online that are worth bookmarking. They are maintained by radiologists for radiologists.

• RadReport.org: This is the RSNA-curated library. It’s comprehensive, peer-reviewed, and covers nearly every modality and subspecialty. It’s the gold standard for structured reporting templates.
• Radiology Templates (AU): Maintained by Australian radiologists, this site offers a fantastic collection of practical, user-friendly templates that are easy to adapt for your own use.

The Next-Level Move: From Manual Templates to AI-Assisted Reporting

Templates are a great foundation, but the real-time crunch happens when you find positive findings. You start free-dictating the location of the clot, the size of the ventricles, the unexpected pneumonia in the left base… and suddenly your clean template is a mess. The next step is turning that free-form dictation back into a perfectly structured report without stopping to manually edit.

This is where tools like GigHz Precision AI come in. You dictate your positive findings naturally, and the AI assistant structures them into the appropriate sections of an ACR or SIR-compliant template. It helps ensure critical measurements like the RV/LV ratio are always included and can prompt you with relevant Clinical Decision Support (CDS) when a specific finding is mentioned. It’s designed to streamline the process of creating high-quality, attending-ready reports from your initial read.

When Should You Order a CTA for Pulmonary Embolism? ACR Appropriateness Criteria

As the radiologist, you’re often the final word on protocoling. Knowing the American College of Radiology (ACR) appropriateness criteria is key. For suspected PE, a CTA is Usually Appropriate in most clinically relevant scenarios.

For a patient with a high pretest probability of PE, or one with a low-to-intermediate probability but a positive D-dimer, a CTA is the recommended first-line imaging test. If the pretest probability is low and the D-dimer is negative, further imaging is often unnecessary. In pregnant patients, while CTA is still considered appropriate, the ACR guidelines often recommend starting with a lower-extremity venous Doppler US and a chest X-ray, with a V/Q scan being a strong alternative to CTA to minimize radiation dose.

The role of CTA extends beyond initial diagnosis. For patients with known PE who are suspected of having recurrent disease, or for surveillance of known chronic thromboembolic disease, CTA is also Usually Appropriate. Critically, the findings on the diagnostic CTA—specifically the presence of right heart strain (RV/LV ratio >0.9) or sustained hypotension—directly inform the ACR criteria for management, helping triage patients between anticoagulation alone versus more aggressive treatments like catheter-directed thrombolysis.

How Much Radiation Does a CTA Pulmonary Embolism Study Deliver?

Patients and ordering providers will ask about radiation dose, and you should know the answer. A CTA PE protocol delivers an estimated effective dose of 3-7 mSv. This places it in the low-to-moderate dose tier for CT scans.

To put that in perspective, this is comparable to the amount of natural background radiation a person receives over the course of several months to a few years. Modern CT scanners use multiple dose-reduction techniques, including automated tube current modulation (adjusting the mA based on patient thickness) and iterative reconstruction algorithms, to keep the dose as low as reasonably achievable (ALARA) while maintaining diagnostic image quality. The CTDIvol (CT Dose Index) should generally be kept under 50-60 mGy, depending on the patient’s size.

CTA Pulmonary Embolism Imaging Protocol — Phases, Contrast, and Reconstructions

A successful PE study is all about timing. The scan itself is incredibly fast—often under 10 seconds—but it must be triggered at the precise moment of peak opacification of the pulmonary arteries. This is achieved using a technique called bolus tracking, where a region of interest (ROI) is placed over the main pulmonary artery trunk. The scanner monitors this ROI, and once the density reaches a predefined threshold (typically ~120 Hounsfield Units), it triggers the scan after a short delay.

Below is a typical protocol structure. Note that specific contrast volumes and flow rates may vary slightly by institution and patient weight.

Common protocol pitfalls: The most frequent reason for a non-diagnostic study is suboptimal contrast opacification. This can be due to poor IV access (use an 18-20 gauge in the antecubital fossa), incorrect ROI placement for bolus tracking (always double-check it’s on the pulmonary trunk), or patient motion/breathing. A good rule of thumb is to check the HU in the pulmonary trunk on your first axial image—if it’s not >250 HU, the study may be limited.

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 the AI will generate a perfectly structured report using ACR and SIR templates. The appropriate Clinical Decision Support (CDS) fires automatically, helping you make the right call every time.

We’re offering extended free access to trainees. All we ask in return is your feedback so we can keep improving the product for the next generation of radiologists.

To apply, just let us know these three things:

1. Your PGY year (e.g., PGY-2, PGY-4)
2. Your training type (radiology residency or specific fellowship)
3. Your training program / hospital name

The signup is simple. No credit card, no long forms. Just reply to the application with the items above and we’ll get you set up. You can apply for the residents free-access program here.

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.

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 information from the PACS or EMR, ensuring compliance with privacy rules.

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 is no software to install and no integration with hospital systems is required.

Does this replace PowerScribe or other dictation software?

No, it works alongside it. You can dictate as you normally would, then use the AI assistant to clean up, structure, and finalize your report before signing it in your primary system. It’s a workflow enhancement, not a replacement.

Can I use this on my phone or iPad?

Yes, the platform is fully responsive and works well on mobile devices and tablets, making it useful for reviewing and editing reports on the go or in the reading room without tying up a main workstation.

Can I customize the templates?

Yes. While the system comes pre-loaded with standard ACR and society-based templates, you can create, modify, and save your own personal templates to match your preferences or your institution’s specific requirements.

What happens after I finish residency or fellowship?

The extended free access is specifically for trainees. After you graduate, you can transition to a standard plan for practicing radiologists. Your customized templates and settings will be saved and carried over to your new account.