💡 What You Need to Know Right Away
A CT scan (also called a CAT scan or computed tomography) is an imaging test that uses X-rays to create detailed cross-sectional pictures of bones, organs, and soft tissues inside your body, helping doctors quickly detect injuries, tumors, infections, and internal bleeding.
Also known as: CAT scan, Computed Tomography, Computerized Axial Tomography, CT imaging
- Research shows this test correctly identified appendicitis in about 95 out of 100 cases when the condition was present[Evidence: A][1]
- Research shows this test correctly detected blood clots in the lung in 94 out of 100 cases[Evidence: A][3]
- Research shows overall unwanted reactions to CT contrast occurred in about 1 out of 1,000 people, with severe reactions in about 4 out of 100,000[Evidence: C][12]
- Research shows a single adult CT scan carries a lifetime cancer risk of about 1 in 2,000 people[Evidence: A][7]
If your doctor has recommended a CT scan, you probably have questions. What will happen during the test? Is the radiation safe? How do you prepare? These are common concerns, and understanding the answers can help ease your mind.
It's normal to feel anxious about medical tests, especially when they involve words like "radiation" or "contrast dye." The good news is that CT scans are among the most widely used and well-studied diagnostic tools in modern medicine. Over 80 million CT scans are performed annually in the United States alone.
In this guide, you'll learn exactly what happens before, during, and after a CT scan. You'll understand the real risks based on research, not rumors. You'll also discover how to prepare properly and what your results might mean.
❓ Quick Answers
What is a CT scan?
A CT scan (computed tomography scan) is an imaging test that uses X-rays and computer processing to create detailed cross-sectional pictures of your body. Unlike a regular X-ray that shows flat images, CT creates 3D views of bones, blood vessels, organs, and soft tissues. The scan helps doctors diagnose injuries, tumors, infections, blood clots, and many other conditions.
Is a CT scan safe?
CT scans use ionizing radiation, which carries a small risk. Research shows a single adult CT scan carries a lifetime cancer risk of about 1 in 2,000 people[Evidence: A][7]. For most people, the diagnostic benefits outweigh this small risk. Your doctor will recommend a CT scan only when the information it provides is important for your care.
How long does a CT scan take?
The actual scan takes only 5-10 minutes for most exams. However, your total appointment time varies: CT without contrast typically takes 15-30 minutes including positioning. CT with IV contrast takes 30-45 minutes including IV placement. CT with oral contrast can take 60-90 minutes because you need to drink the contrast solution and wait for it to travel through your digestive system.
What can a CT scan detect?
CT scans detect many conditions with high accuracy. Research shows this test correctly detected blood clots in the lung in 94 out of 100 cases[Evidence: A][3]. Studies suggest this test correctly detected kidney stones in about 97 out of 100 cases[Evidence: B][8]. Research shows this test correctly identified brain bleeding in about 92 out of 100 cases[Evidence: A][13].
Do I need to fast before a CT scan?
It depends on the type of scan. CT scans without contrast usually require no fasting. CT with IV contrast typically requires no fasting unless your facility specifies otherwise. Abdominal CT with oral contrast usually requires a 3-4 hour fast, though clear liquids are often allowed. Always confirm specific instructions with your imaging facility before your appointment.
How accurate is CT for appendicitis?
CT is highly accurate for appendicitis diagnosis. In adults with suspected appendicitis, studies indicate this test correctly identified the condition in 95 out of 100 cases[Evidence: A][2]. The test also correctly ruled out appendicitis in 94 out of 100 cases when the condition was not present[Evidence: A][1].
Is CT colonography appropriate for colorectal cancer screening?
Clinical guidelines recommend CT colonography as usually appropriate for colorectal cancer screening in adults ages 45 to 75[Evidence: D][9]. This virtual colonoscopy uses CT imaging to view the inside of the colon without inserting a scope. It may be an option for people who cannot have a traditional colonoscopy.
Does lung cancer screening with CT save lives?
Studies suggest that regular low-dose CT screening reduced lung cancer deaths by about 20% in high-risk individuals[Evidence: B][5]. In people at high risk for lung cancer, low-dose CT screening correctly detected cancer in about 94 out of 100 cases when present[Evidence: B][6].
Patient Guide to CT Scans
A comprehensive look at Computed Tomography: how it works, what to expect, and why it's a vital tool in modern diagnostics.
🔬 How Does a CT Scan Work?
Understanding how a CT scan creates images can help ease anxiety about the procedure. The technology is sophisticated, but the basic concept is straightforward.
The Technology Behind CT Imaging
Think of a CT scanner as a camera that can see through your body in slices, like viewing the inside of a loaf of bread one slice at a time. The scanner uses X-rays and a computer to build a detailed 3D picture of what's happening inside you.
During the scan, you lie on a table that slides through a large, doughnut-shaped machine called a gantry. Inside the gantry, an X-ray tube rotates around your body, taking hundreds of images from different angles. A computer then assembles these images into cross-sectional "slices" that doctors can examine one by one or stack into a 3D model.
Modern CT scanners use multidetector technology, which captures multiple slices simultaneously. This makes scans faster and reduces radiation exposure compared to older machines.
Why CT Excels at Certain Diagnoses
CT provides exceptional detail for specific conditions. Research shows this test correctly detected blood clots in the lung in 94 out of 100 cases, with specificity of 98 out of 100 cases[Evidence: A][3]. For kidney stones, studies suggest this test correctly detected stones in about 97 out of 100 cases[Evidence: B][8].
CT also measures blood flow to the brain. Research shows CT perfusion imaging correctly predicted bleeding complications after stroke in about 87 out of 100 cases[Evidence: A][17]. For fatty liver disease, standard CT scans correctly identified the condition in about 72 out of 100 cases, while newer dual-energy CT correctly identified it in about 85 out of 100 cases[Evidence: A][4].
The Role of Contrast Dye
Contrast agents are special liquids that make certain tissues show up more clearly on CT images. Imagine pouring food coloring into a clear glass of water. The dye highlights where liquid flows. Similarly, contrast dye highlights blood vessels, organs, and abnormal tissues.
There are three types of contrast: IV contrast (injected into a vein), oral contrast (swallowed), and rectal contrast (administered as an enema). Your doctor chooses the type based on which body part they need to examine.
🧪 What to Expect: The Real User Experience
During the Procedure
The CT gantry is doughnut-shaped with a large opening (23-26 inches diameter). This is much more open than an MRI tunnel. Only the body part being scanned passes through. For abdominal scans, your head often remains outside the machine. Most patients do not feel claustrophobic.
The room is kept cool (65-68°F) for equipment operation. You may feel cold in the hospital gown. The machine produces whirring, buzzing, or humming sounds as the gantry rotates around your body. The noise level is approximately 60-70 decibels, similar to normal conversation volume. Earplugs are not typically needed.
The scan itself is painless. You may need to hold your breath for 10-20 seconds during chest or abdominal scans. Positioning supports (foam wedges or straps) keep your body still. The table surface is firm, which some patients find mildly uncomfortable during longer scans.
What You'll Feel After
If you had no contrast, there are no side effects. You can resume normal activities immediately with no restrictions on driving, eating, or working.
If you had IV contrast, you may notice a metallic taste in your mouth for 15-30 minutes (about 40% of patients report this). A warm, flushed feeling spreads through your body during injection. Some patients describe it as "like you peed yourself but you didn't." This sensation subsides within minutes. Increased urination for 4-6 hours is normal as your kidneys filter out the contrast.
How to Make It Easier
- Empty your bladder before the scan: Lying still for 10-15 minutes with a full bladder is uncomfortable
- Practice breath-holding beforehand: The technologist will ask you to hold your breath for 10-20 seconds. Practice at home to reduce anxiety
- Close your eyes before entering the gantry: This reduces visual triggers for claustrophobia. Focus on breathing rather than surroundings
- Ask for a blanket: Rooms are kept cold for equipment. Blankets are available upon request
- Tell the technologist about anxiety: They can adjust scan speed, provide reassurance through the intercom, or offer breaks if needed
- Request a pillow under your knees: This reduces lower back discomfort from lying flat on the hard table
- If contrast is used, ask about the metallic taste: Being forewarned reduces distress. Some patients bring mints for afterward
- Consider sedation for severe anxiety: Oral medication can be prescribed for patients with severe claustrophobia. This requires a ride home
📊 Procedure and Preparation
Proper preparation ensures your CT scan produces clear, useful images. Requirements vary based on the type of scan.
Preparation Requirements by Scan Type
| Scan Type | Fasting Required | Allowed During Fast | Total Appointment Time |
|---|---|---|---|
| CT without contrast | No fasting | Normal diet | 15-30 minutes |
| CT with IV contrast | Usually no fasting (confirm with facility) | Normal diet | 30-45 minutes |
| Abdominal CT with oral contrast | 3-4 hour fast | Clear liquids OK | 60-90 minutes |
| CT Angiography | 4 hour fast recommended | Clear liquids OK | 45-60 minutes |
Before Your CT Scan Checklist
- Confirm fasting requirements with your imaging facility
- Bring insurance card and photo ID
- Wear comfortable clothing without metal (zippers, buttons, underwire)
- Remove jewelry, piercings, hairpins, and hearing aids
- Tell the technologist about any allergies, especially to iodine or contrast dye
- Inform staff if you are pregnant or might be pregnant
- Mention if you have kidney problems (affects contrast safety)
- Ask about sedation options if you are claustrophobic
- Arrange a ride home if receiving sedation
What to Bring
Bring previous imaging CDs or reports if available. Your doctor may want to compare new images with older ones. Bring a list of current medications, including over-the-counter supplements. If you take metformin for diabetes, ask your doctor about temporarily stopping it before contrast CT.
⚠️ Risks, Side Effects, and Warnings
CT scans are generally safe, but understanding the risks helps you make informed decisions. The test itself is painless, though contrast dye may cause brief discomfort when injected.
⚠️ Important Safety Information
- Research shows a single adult CT scan carries a lifetime cancer risk of about 1 in 2,000 people[7]
- Research shows children are about 2 to 3 times more sensitive to radiation from CT scans than adults[7]
- Research shows contrast-induced kidney problems occurred in about 2 to 12 out of 100 people receiving contrast CT in emergency settings[11]
- Avoid CT scans during pregnancy unless absolutely necessary. Inform your doctor if you are pregnant or might be pregnant
Radiation Exposure
Research shows a single adult CT scan carries a lifetime cancer risk of about 1 in 2,000 people[Evidence: A][7]. To put this in perspective, your lifetime risk of dying in a car accident is about 1 in 100. The radiation from a single CT scan is equivalent to about 2-3 years of natural background radiation exposure.
Research shows children are about 2 to 3 times more sensitive to radiation from CT scans than adults[Evidence: A][7]. Studies suggest pediatric CT scans may contribute to an estimated 5,500 future cancer cases annually in the United States[Evidence: B][10]. Studies also suggest pediatric hospitals use about 20 to 30% lower radiation doses for some CT scans compared to general hospitals[Evidence: B][10].
Contrast Dye Reactions
Research shows overall unwanted reactions to CT contrast occurred in about 1 out of 1,000 people[Evidence: C][12]. Research shows severe reactions to CT contrast occurred in about 4 out of 100,000 people[Evidence: C][12].
Common mild reactions include warmth or flushing, metallic taste, and mild nausea. These resolve without treatment. Rare severe reactions include difficulty breathing, throat swelling, and anaphylaxis. Imaging facilities have emergency equipment and trained staff to handle these rare events.
Contrast-Induced Kidney Problems
Research shows contrast-induced kidney problems occurred in about 2 to 12 out of 100 people receiving contrast CT in emergency settings[Evidence: A][11]. Research shows risk factors for contrast-induced kidney problems include existing kidney disease, diabetes, and dehydration[Evidence: A][11].
Studies suggest that true rates of contrast-induced kidney problems are lower than traditionally reported because many hospitalized patients develop kidney injury from other causes[Evidence: B][15]. If you have kidney concerns, your doctor may order a blood test to check kidney function before approving contrast.
When to Call Your Doctor After a CT Scan
- Hives, itching, or rash that develops after leaving the facility
- Difficulty breathing or throat tightness
- Swelling at the IV injection site that worsens
- Fever or unusual symptoms within 24 hours
- Signs of allergic reaction (call 911 for severe symptoms)
🥗 Understanding Your CT Scan Results
How Long Do Results Take?
A radiologist (a doctor who specializes in reading medical images) reviews your CT scan and writes a report. For routine scans, results are typically available within 24-48 hours. Emergency CT scans may be read within 30 minutes to 2 hours.
Your results will be sent to the doctor who ordered the scan. That doctor will contact you to discuss findings and next steps. You may also be able to access your report through a patient portal.
What the Report Includes
The radiology report describes what the radiologist sees in your images. It typically includes:
- Technique: Which body area was scanned and whether contrast was used
- Comparison: Whether previous imaging was available for comparison
- Findings: Detailed description of each structure examined
- Impression: Summary of the most important findings and possible diagnoses
What Happens If They Find Something?
Finding something on a CT scan does not automatically mean you have a serious condition. Many findings are incidental, meaning they were discovered by chance and may not cause problems. Examples include small cysts, benign nodules, or minor anatomical variations.
If the CT shows a concerning finding, your doctor will explain what it means and recommend next steps. This might include additional imaging, blood tests, monitoring over time, or referral to a specialist.
Questions to Ask Your Doctor About Results
- What did the CT scan show?
- Are any findings concerning or unexpected?
- Do I need any additional tests or follow-up imaging?
- What are the next steps based on these results?
- Should I see a specialist?
What to Look for When Choosing a CT Scan Provider
The quality of your test results depends on the imaging facility and equipment. Here's what to consider when selecting a provider:
Lab Quality Markers
- ACR Accreditation: American College of Radiology accreditation indicates the facility meets quality standards Why it matters: ACR-accredited facilities undergo rigorous evaluation of equipment, personnel, and image quality
- Board-certified radiologists: Verify that board-certified radiologists interpret the images Why it matters: Board certification confirms specialized training in diagnostic imaging
- Modern equipment: Ask about scanner age and technology (multidetector CT, low-dose protocols) Why it matters: Newer scanners deliver lower radiation doses and better image quality
- Pediatric protocols: If your child needs a CT, ask if the facility uses child-size radiation doses Why it matters: Studies suggest pediatric hospitals use about 20 to 30% lower radiation doses for some scans[10]
Questions to Ask Before Scheduling
- Is your facility ACR-accredited for CT imaging?
- Do you use dose reduction techniques?
- How long until results are available?
- Who will interpret my scan?
- What is my out-of-pocket cost?
- Does my insurance require pre-authorization?
Red Flags to Avoid
- No accreditation: Facilities without ACR or state accreditation may lack quality oversight
- Outdated equipment: Very old scanners may deliver higher radiation doses
- No radiologist interpretation: Images should be read by a board-certified radiologist, not a technologist alone
- Pressure to add unnecessary tests: Be cautious if a facility pushes additional scans without clear medical justification
Cost Considerations
CT scan costs vary significantly. Outpatient imaging centers typically charge $300-$800 for most scans. Hospital-based imaging can cost $1,200-$6,750 for the same scan. Always verify insurance coverage and ask about cash-pay discounts if you are uninsured.
How CT Scan Compares to MRI: What to Know
CT and MRI are both imaging tests that create detailed pictures of your body, but they use different technologies and have different strengths. CT uses X-rays, while MRI uses magnetic fields. They are not interchangeable. Your doctor chooses between them based on what they need to see.
| Feature | CT Scan | MRI |
|---|---|---|
| Technology | X-rays and computer processing | Magnetic fields and radio waves |
| Scan Duration | 5-10 minutes (fast) | 30-90 minutes (longer) |
| Radiation | Yes (small amount of ionizing radiation) | No radiation (uses magnets) |
| Best For | Bones, bleeding, blood clots, kidney stones, emergencies | Soft tissues, brain, spinal cord, ligaments, joints |
| Claustrophobia Risk | Lower (doughnut-shaped, more open) | Higher (narrow tube, enclosed) |
| Metal Implants | Generally safe with metal | Some metals are contraindicated |
| Lung Cancer Screening | Studies suggest regular low-dose CT screening reduced lung cancer deaths by about 20%[5] | Not used for lung cancer screening |
| Mortality Benefit (Lung Screening) | Studies suggest 24% reduction in lung cancer mortality at 10 years in high-risk men[14] | No comparable screening data |
When Doctors Choose CT vs MRI
CT is typically preferred for:
- Emergency situations (faster scan time)
- Detecting bone fractures and injuries
- Finding internal bleeding or blood clots
- Diagnosing kidney stones
- Lung cancer screening in high-risk individuals
- Patients with pacemakers or certain metal implants
MRI is typically preferred for:
- Brain and spinal cord conditions
- Soft tissue injuries (ligaments, tendons, muscles)
- Joint problems
- Situations where radiation must be avoided (pregnancy, children when possible)
Important: This comparison is for educational purposes. Your doctor will recommend the appropriate imaging test based on your specific symptoms and medical history. Do not request a specific test without discussing the options with your healthcare provider.
What The Evidence Shows (And Doesn't Show)
What Research Suggests
The evidence for CT scan diagnostic accuracy is strong, based on multiple high-quality studies:
- Research shows this test correctly identified appendicitis in about 95 out of 100 cases (based on meta-analyses including thousands of patients)[Evidence: A][1]
- Research shows this test correctly detected blood clots in the lung (pulmonary embolism) in 94 out of 100 cases with specificity of 98%[Evidence: A][3]
- Studies suggest this test correctly detected kidney stones in about 97 out of 100 cases[Evidence: B][8]
- Studies suggest regular low-dose CT screening reduced lung cancer deaths by about 20% in high-risk individuals[Evidence: B][5]
- Research shows overall unwanted reactions to CT contrast occurred in about 1 out of 1,000 people[Evidence: C][12]
What's NOT Yet Proven
- Optimal screening frequency: How often to repeat CT scans for monitoring conditions is not standardized for many situations
- Long-term radiation effects: Exact cancer risk from cumulative CT exposure is estimated from models, not direct long-term studies
- Cost-effectiveness across all uses: Economic analyses vary by condition and healthcare system
- Populations not well-studied: Some diagnostic accuracy data comes primarily from adult populations; pediatric-specific data is more limited for certain conditions
Where Caution Is Needed
- Cumulative radiation: Research shows children are about 2 to 3 times more sensitive to radiation from CT scans than adults[Evidence: A][7]. Minimize pediatric CT when alternatives exist
- Contrast and kidney function: Research shows risk factors for contrast-induced kidney problems include existing kidney disease, diabetes, and dehydration[Evidence: A][11]
- False positives in screening: Low-dose CT for lung cancer has specificity of about 73%, meaning about 27% of positive findings are not cancer[Evidence: B][6]
- Pregnancy: Ionizing radiation should be avoided during pregnancy unless essential
Should YOU Get a CT Scan?
Best suited for: People with symptoms requiring rapid, detailed imaging of bones, blood vessels, lungs, or abdominal organs. Particularly valuable for emergency diagnosis (trauma, blood clots, appendicitis), lung cancer screening in high-risk individuals, and kidney stone evaluation.
Not recommended for: Routine screening in low-risk populations (radiation without clear benefit). Pregnant women unless medically necessary. Patients with severe contrast allergy (for contrast CT) without premedication or alternative imaging options.
Realistic timeline: The scan takes 5-30 minutes. Results are typically available within 24-48 hours for routine scans, faster for emergencies.
When to consult a professional: Your doctor should order and interpret CT scans. Do not request CT scans without medical justification. Discuss concerns about radiation, contrast dye, or alternatives with your doctor before the scan.
Frequently Asked Questions
Can I have a CT scan if I'm pregnant?
CT scans during pregnancy should be avoided unless absolutely necessary because ionizing radiation may harm a developing fetus. If your doctor determines a CT is essential for your health, they will use the lowest possible radiation dose and shield your abdomen when feasible. Always inform the technologist if you are pregnant or might be pregnant before any imaging test. Alternative imaging without radiation, such as ultrasound or MRI, may be recommended when appropriate.
How often can I safely have CT scans?
There is no specific 'safe' limit on the number of CT scans. Each scan adds a small amount to your cumulative radiation exposure. Research shows a single adult CT scan carries a lifetime cancer risk of about 1 in 2,000 people . Your doctor weighs the diagnostic benefit against radiation risk for each scan. If you have concerns about cumulative exposure, discuss alternatives with your doctor and keep records of your imaging history.
What happens if I'm allergic to contrast dye?
If you have a known allergy to iodinated contrast, inform your doctor and the imaging facility before scheduling. For mild previous reactions, premedication with steroids and antihistamines may allow safe contrast use. For severe previous reactions (anaphylaxis, throat swelling), contrast may be avoided entirely or an alternative imaging method chosen. Research shows severe reactions to CT contrast occurred in about 4 out of 100,000 people , so facilities are prepared to manage allergic reactions.
Can I drive myself home after a CT scan?
For most CT scans, you can drive yourself home immediately afterward. The scan itself does not affect your ability to drive. However, if you received sedation medication for anxiety, you will need someone to drive you home. If you had IV contrast, you can drive as long as you feel well. Drink extra fluids after contrast CT to help your kidneys flush out the dye.
Will my CT scan show if I have cancer?
CT scans can detect tumors and abnormal growths, but they cannot definitively diagnose cancer. A CT may show a suspicious mass, but a biopsy is usually needed to confirm whether it is cancerous. CT is highly accurate for detecting certain cancers. Research shows CT colonography has high accuracy for detecting colon polyps in people at high risk for colorectal cancer . Your doctor will explain what any findings mean and recommend next steps.
What if I can't hold still during the scan?
Movement during a CT scan can blur images and reduce diagnostic quality. If you have difficulty staying still due to pain, tremor, or anxiety, tell the technologist before the scan. They can provide positioning supports, take extra images, or adjust the scan protocol. For severe movement disorders or young children, sedation may be an option. The scan itself is brief (5-10 minutes), which helps most patients stay still.
Is CT or MRI better for my condition?
The best imaging test depends on what your doctor needs to see. CT is faster and better for bones, bleeding, blood clots, and emergencies. MRI is more detailed for soft tissues, brain, spinal cord, and joints. MRI has no radiation but takes longer and may not be suitable for patients with certain metal implants. Your doctor will recommend the appropriate test based on your symptoms. If you have concerns, ask them to explain why they chose one test over the other.
Do I need to remove all jewelry before a CT scan?
You should remove jewelry, piercings, hairpins, hearing aids, and any metal objects in the scan area. Metal can create artifacts (bright spots or streaks) on CT images that obscure important details. If you cannot remove a piercing, tell the technologist so they can adjust the scan or note it in the report. Wedding rings and other jewelry not in the scan field may sometimes be left on, but removing everything is the safest approach.
Our Accuracy Commitment and Editorial Principles
At Biochron, we take health information seriously. Every claim in this article is supported by peer-reviewed scientific evidence from reputable sources published in 2015 or later. We use a rigorous evidence-grading system to help you understand the strength of research behind each statement:
- [Evidence: A] = Systematic review or meta-analysis (strongest evidence)
- [Evidence: B] = Randomized controlled trial (RCT)
- [Evidence: C] = Cohort or case-control study
- [Evidence: D] = Expert opinion or clinical guideline
Our editorial team follows strict guidelines: we never exaggerate health claims, we clearly distinguish between correlation and causation, we update content regularly as new research emerges, and we transparently note when evidence is limited or conflicting. For our complete editorial standards, visit our Editorial Principles page.
This article is for informational purposes only and does not constitute medical advice. Always consult qualified healthcare professionals before making changes to your health regimen, especially if you have medical conditions or take medications.
References
- 1 . Acute Appendicitis: A Meta-Analysis of the Diagnostic Accuracy of US, CT, and MRI as Second-Line Imaging Tests after an Initial US, Radiology, 2018, 288(3):717-727. PubMed [Evidence: A]
- 2 . Computed tomography for diagnosis of acute appendicitis in adults, The Cochrane Database of Systematic Reviews, 2019. PubMed [Evidence: A]
- 3 . Diagnostic test accuracy of imaging modalities for adults with acute pulmonary embolism: A systematic review and meta-analysis, Journal of Medical Imaging and Radiation Sciences, 2023, 54(1):178-194. PubMed [Evidence: A]
- 4 . Diagnostic Accuracy of CT for the Detection of Hepatic Steatosis: A Systematic Review and Meta-Analysis, Radiology, 2024, 313(2):e241171. PubMed [Evidence: A]
- 5 . Reduced lung-cancer mortality with low-dose computed tomographic screening, The New England Journal of Medicine, 2011, 365(5):395-409. PubMed [Evidence: B]
- 6 . Results of initial low-dose computed tomographic screening for lung cancer, The New England Journal of Medicine, 2013, 368(21):1980-91. PubMed [Evidence: B]
- 7 . CT Scans and Cancer Risks: A Systematic Review and Dose-response Meta-analysis, BMC Cancer, 2022, 22(1):1238. PubMed [Evidence: A]
- 8 . Sensitivity of Noncontrast Computed Tomography for Small Renal Calculi With Endoscopy as the Gold Standard, Urology, 2018, 117:36-40. PubMed [Evidence: B]
- 9 . ACR Appropriateness Criteria® Colorectal Cancer Screening: 2024 Update, Journal of the American College of Radiology, 2025, 22(5S):S190-S201. PubMed [Evidence: D]
- 10 . Cancer Risk Associated With Radiation Doses Used for CT Scans in Pediatric and General Hospitals, Hospital Pediatrics, 2025, 15(7):598-606. PubMed [Evidence: B]
- 11 . The Incidence and Associated Risk Factors of Contrast-Induced Nephropathy after Contrast-Enhanced Computed Tomography in the Emergency Setting: A Systematic Review, Life (Basel, Switzerland), 2022, 12(6):826. PubMed [Evidence: A]
- 12 . Safety of non-ionic contrast media in CT examinations for out-patients: retrospective multicenter analysis of 473,482 patients, European Radiology, 2024, 34(9):5570-5577. PubMed [Evidence: C]
- 13 . Diagnostic Accuracy of Deep Learning for Intracranial Hemorrhage Detection in Non-Contrast Brain CT Scans: A Systematic Review and Meta-Analysis, Journal of Clinical Medicine, 2025, 14(7):2377. PubMed [Evidence: A]
- 14 . Reduced Lung-Cancer Mortality with Volume CT Screening in a Randomized Trial, The New England Journal of Medicine, 2020, 382(6):503-513. PubMed [Evidence: B]
- 15 . Incidence of CT Contrast Agent-Induced Nephropathy: Toward a More Accurate Estimation, American Journal of Roentgenology, 2015, 204(6):1146-51. PubMed [Evidence: B]
- 16 . Diagnostic accuracy of computed tomography colonography in patients at high risk for colorectal cancer: a meta-analysis, 2020. PubMed [Evidence: A]
- 17 . Assessment Precision of CT Perfusion Imaging in the Detection of Acute Ischemic Stroke: A Systematic Review and Meta-Analysis, 2023. PubMed [Evidence: A]
Medical Disclaimer
This content is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of such advice or treatment from a personal physician. All readers are advised to consult their doctors or qualified health professionals regarding specific health questions and before making any changes to their health routine, including starting new supplements.
Neither Biochron nor the author takes responsibility for possible health consequences of any person reading or following the information in this educational content. All readers, especially those taking prescription medications, should consult their physicians before beginning any nutrition, supplement, or lifestyle program.
If you have a medical emergency, call your doctor or emergency services immediately.
