CT Abdomen/Pelvis Without Contrast (Renal Stone) — Dictation, Appropriateness, and Dose for Residents
1. The Stat Renal Stone CT: More Than Just a Rock Hunt
It’s a classic call. Stat from the Emergency Department: 34-year-old, acute left flank pain radiating to the groin, microscopic hematuria. The ED attending is sure it’s a kidney stone and wants to know if it’ll pass. You’ve got a busy list, and while the read itself seems straightforward, your attending expects you to not only find the stone but also to measure it, give its density, grade the hydro, and—most importantly—not miss the appendicitis that’s masquerading as renal colic. When I was a resident, it was easy to get tunnel vision on these, hunting for the stone and nothing else. That’s a trap. This scan is a diagnostic gateway, and your report needs to be comprehensive and fast. For more high-yield guides like this, check out our free trainee calculators and references.
2. What a CT Abdomen and Pelvis (Renal Stone Protocol) Covers and What Attendings Look For
A non-contrast CT of the abdomen and pelvis, or “renal stone protocol,” is the gold standard for evaluating suspected urolithiasis in non-pregnant adults. It’s a low-dose, rapid scan designed to answer a few critical questions for the urology and emergency medicine teams. There’s no IV or oral contrast, making it quick to perform.
Your attending (and the ordering clinician) expects your report to definitively answer:
- Are there stones? Identify their location (kidney, ureteropelvic junction (UPJ), mid-ureter, ureterovesical junction (UVJ)), size in two dimensions, and density in Hounsfield Units (HU).
- Is there obstruction? Look for secondary signs like hydronephrosis (dilation of the renal pelvis and calyces) and hydroureter (dilation of the ureter). Grade the hydronephrosis.
- Are there perinephric changes? Note any perinephric fat stranding or fluid, which indicates inflammation from an obstructing stone.
- Is there an alternative diagnosis? This is crucial. Systematically evaluate the appendix, colon, ovaries, aorta, and other structures to rule out appendicitis, diverticulitis, ovarian torsion, or a leaking abdominal aortic aneurysm (AAA).
3. Radiology Report Template for CT Abdomen and Pelvis Without Contrast (Renal Stone Protocol)
This is a solid starting point for your personal macro. Drop this into your dictation system and adapt as needed. Remember, the coronal reformats are your best friend for tracing the ureters from the renal pelvis down to the bladder.
Technique
Non-contrast computed tomography of the abdomen and pelvis was performed using a low-dose renal stone protocol. Axial images were acquired and supplemented with coronal and sagittal reformats.
Findings
Kidneys and Ureters:
Right Kidney: [Normal in size and appearance. No hydronephrosis. No renal calculi.] OR [Mild/moderate/severe hydronephrosis. A [size] mm hyperdense calculus is present in the [location, e.g., interpolar region/upper pole calyx], measuring [number] HU. Additional nonobstructing calculi are noted.]
Right Ureter: [Normal in caliber without ureteral calculus.] OR [Dilated to [size] mm proximal to a [size] mm calculus at the [location, e.g., ureteropelvic junction/proximal ureter at the level of the iliac vessels/ureterovesical junction]. Associated perinephric and periureteral fat stranding is present.]
Left Kidney: [Normal in size and appearance. No hydronephrosis. No renal calculi.] OR [Mild/moderate/severe hydronephrosis. A [size] mm hyperdense calculus is present in the [location], measuring [number] HU.]
Left Ureter: [Normal in caliber without ureteral calculus.] OR [Dilated to [size] mm proximal to a [size] mm calculus at the [location].]
Bladder: Normal in appearance. No bladder calculi.
Other Organs:
Liver, Gallbladder, Spleen, Pancreas, Adrenal Glands: Unremarkable.
Bowel and Mesentery: No evidence of bowel obstruction or inflammation. The appendix is [visualized and normal in appearance / not well visualized]. No diverticulitis.
Vasculature: The visualized aorta is normal in caliber without evidence of aneurysm or dissection.
Pelvic Organs: The uterus and ovaries are unremarkable (if applicable).
Bones and Soft Tissues: No acute osseous abnormality. Visualized lung bases are clear.
Impression
1. [Size] mm obstructing calculus in the [location, e.g., right distal ureter at the ureterovesical junction].
2. Associated moderate right hydroureteronephrosis and perinephric fat stranding.
3. Additional nonobstructing calculi in the [location, e.g., left kidney].
4. No CT evidence of an alternative acute process such as appendicitis or diverticulitis.
4. Free Template Sources for Your Personal Library
Building a robust set of personal dictation templates is a key part of residency. Beyond what you collect from your attendings and senior residents, two great free repositories exist online. They are excellent resources for finding standardized language and structure for studies you may not read frequently.
- RadReport.org: Maintained by the Radiological Society of North America (RSNA), this is a comprehensive library of peer-reviewed templates covering nearly every modality and subspecialty. (https://radreport.org/)
- Radiology Templates (AU): An excellent, user-friendly site maintained by Australian radiologists with a clean interface and practical, well-structured templates. (https://www.radiologytemplates.com.au/home-page/)
5. The Next-Level Move: Free-Form Dictation with AI-Powered Structuring
Templates are essential, but meticulously clicking through fields and deleting negative statements can be a drag, especially on a busy call shift. The real goal is to get the positive findings out of your head and into a perfectly structured report as efficiently as possible. This is where AI-assisted reporting tools can make a significant difference in your workflow.
Instead of navigating a rigid template, you can dictate the key findings in free form: “There is a 6 mm calculus at the right UVJ with moderate hydroureteronephrosis and perinephric stranding.” GigHz Precision AI parses this, identifies the measurements and clinical terms, and automatically populates a clean, structured report based on pre-loaded ACR and SIR standards. It’s designed to streamline the process, letting you focus on the diagnostic task while the AI handles the clerical work of formatting the report correctly.
6. When Should You Order a CT Abdomen and Pelvis for Suspected Kidney Stones? ACR Appropriateness Criteria
The American College of Radiology (ACR) provides evidence-based guidelines to help clinicians choose the right test for the right reason. For suspected kidney stones, the recommendations are quite clear.
For an adult patient presenting with acute flank pain and suspicion of a kidney stone for the first time, a CT of the abdomen and pelvis without contrast is “Usually Appropriate” and considered the first-line imaging modality. The same applies to a patient with a known history of stones who presents with recurrent symptoms; a non-contrast CT is again “Usually Appropriate” to assess for a new or moved stone and the degree of obstruction.
However, the situation changes for pregnant patients. Due to the need to minimize radiation exposure to the fetus, for a pregnant patient with acute flank pain, a renal and bladder ultrasound is the “Usually Appropriate” first-line study. If the ultrasound is inconclusive, an MRI of the abdomen and pelvis without contrast (an MR Urogram) may be considered.
If a non-contrast CT is performed but is inconclusive for stones (a rare event, but possible with certain stone types or artifacts), a CT Urogram (with contrast) may be appropriate as the next step to evaluate for other causes of obstruction or hematuria.
7. How Much Radiation Does a Renal Stone Protocol CT Deliver?
One of the most common questions from patients and referring providers concerns radiation dose. A key advantage of the renal stone protocol is that it is specifically designed to be a low-dose study. The estimated effective dose for a low-dose renal stone protocol CT is typically in the range of 2-6 mSv.
To put this in perspective, a standard contrast-enhanced CT of the abdomen and pelvis carries a dose of about 8-12 mSv. The renal stone protocol delivers about half that dose. This 2-6 mSv exposure is comparable to the amount of natural background radiation a person receives over several months to a couple of years.
This dose reduction is achieved through specific technical adjustments, including using lower kVp settings (especially in smaller patients), automated tube current modulation, and the use of iterative reconstruction algorithms, which help maintain image quality while reducing noise at lower radiation levels.
| Scan Type | Typical Effective Dose (mSv) | Comparison |
|---|---|---|
| CT Abdomen/Pelvis (Renal Stone Protocol) | 2 – 6 mSv | Low Dose |
| Standard CT Abdomen/Pelvis (with contrast) | 8 – 12 mSv | Standard Dose |
| Chest X-ray (PA/LAT) | ~0.1 mSv | Very Low Dose |
| Annual Natural Background Radiation (US) | ~3 mSv | Baseline |
8. CT Abdomen and Pelvis (Renal Stone Protocol) Imaging Protocol — Phases, Contrast, and Reconstructions
The beauty of the renal stone protocol is its simplicity. It’s a single, fast, non-contrast acquisition designed to make hyperdense calculi stand out. The patient is typically scanned supine, from the top of the kidneys through the pubic symphysis, in a single breath-hold. Prone imaging is sometimes used as an adjunct to differentiate a stone stuck at the UVJ from one that has already passed into the bladder.
The primary goal is to optimize stone conspicuity while minimizing radiation dose. This is achieved with a combination of automated exposure control, appropriate kVp selection based on patient size, and modern iterative reconstruction techniques.
| Phase / Reconstruction | Contrast | Key Parameters | Purpose |
|---|---|---|---|
| Topogram (Scout) | None | 120 kVp | Planning the scan range. |
| Helical Acquisition | None | kVp: 100-120 (auto or size-based); mAs: Auto-modulated (low); Pitch: >1.0; Coverage: Above kidneys to pubic symphysis. | Primary data acquisition. Low kVp (80-100) is excellent for slim patients to reduce dose and increase stone conspicuity. |
| Soft Tissue Recons | N/A | Slice Thickness: 3-5 mm; Iterative Reconstruction: 50-80% strength. | Standard review of anatomy and alternative pathologies. |
| Thin-Slice Recons | N/A | Slice Thickness: 1-1.25 mm. | Used to generate high-quality multiplanar reformats (MPR). |
| Coronal/Sagittal MPR | N/A | Generated from thin-slice data. | High-yield for tracing ureters and pinpointing stone location. |
Common protocol pitfalls: A frequent miss is not using a lower kVp (e.g., 100 or even 80) in smaller patients. This single change can substantially reduce radiation dose without compromising diagnostic quality for stone detection. Another tip: if you’re struggling to decide if a calcification is at the UVJ or just inside the bladder, a quick prone scan can be diagnostic. A UVJ stone will remain fixed, while a bladder stone will roll to the dependent portion of the bladder.
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. With the GigHz Radiology Report Assistant, you can dictate your positive findings in free form, and the AI generates a perfectly structured report using ACR and SIR templates. The appropriate Clinical Decision Support (CDS) can fire automatically, guiding you to the right classifications without breaking your workflow.
All we ask in return is your feedback so we can keep improving the product for trainees. Signup is simple—no credit card, no long forms. To get started, just provide 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 streamline your reporting? Apply for the residents free-access program and we’ll get you set up.
10. Frequently Asked Questions
Is GigHz Precision AI HIPAA-compliant?
Yes. The platform is designed for de-identified workflows by default. It processes the clinical content of your dictation without requiring Protected Health Information (PHI), ensuring compliance with HIPAA privacy and security standards.
Does this require a complex IT setup at my hospital?
No. GigHz Precision AI is browser-based and requires no local software installation or integration with hospital IT systems. It works on any modern computer, including the PACS workstation or your personal laptop or iPad in the call room.
Can I use this alongside PowerScribe or other dictation systems?
Absolutely. Most residents use it in a “copy-paste” workflow. You dictate into the GigHz web interface, let the AI structure the report, and then copy the final, clean text into your hospital’s official dictation system for sign-off.
Can I customize the templates?
Yes. While the system comes pre-loaded with ACR and other society-standard templates, you can create, modify, and save your own personal templates to match your preferences or your institution’s specific formatting requirements.
What happens after my residency or fellowship ends?
We offer continuity plans for graduating trainees who want to continue using the platform in their practice. The free access program is specifically for residents and fellows currently in training.
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
