Author: Logan Young

Indeed, photon-counting CT (PCCT) offers a massive leap in spatial resolution for detecting submillimeter metastatic nodules in children. But as Joseph Cao, MD, called in the ARRS Online Course PCCT: It Counts in Children, Too, it isn’t a free lunch either. Maximizing performance requires a careful balance between resolution, noise, and kernel selection—especially for long-term follow-up of osteosarcoma, when the ability to identify tiny metastatic lung nodules as patients age is so very vital.

Noise Trade: Whereas UHR mode at 0.2 mm offers incredible detail, alas, it does introduce a whole lotta static.

• Cost: This noise must be compensated for via increased radiation dose or higher levels of iterative reconstruction, which can still result in grainy images.
• Alternative: Cao suggests that 0.4 mm reconstructions—already superior to prior scanner generations—may provide the sweet spot for detecting submillimeter nodules sans the noise penalty.

Edge Watch: Kernel selection significantly impacts image quality in the lung parenchyma.

• Flaw: Using standard BL kernels on current PCCT platforms can cause a distinct loss of signal along the pleural interface.
• Fix: Quantitative kernels preserve this signal, maintaining the integrity of the edge across various iterative reconstruction levels.

RadFYI: Don’t rely solely on out-of-the-box vendor packages. Rads can run 20 or more different reconstruction variations to determine which settings work best for their specific pediatric populations.

Molecular breast imaging (MBI) continues to gain traction as an efficient supplemental screening tool, balancing clinical utility with ease of implementation for rads and patients alike. Unlike purely anatomical imaging, MBI highlights metabolically active lesions.

And as Amy Lynn Conners, MD, explained during “Streamlining Breast Imaging Workflows” at ARRS 2026, this feature makes it popular with oncologists, who often view these active findings as more “threatening” to the patient.

Pros:

• Ease of Adoption: MBI acquisition is not highly operator-dependent, and the learning curve for rads is short. Dr. Conners noted one practice successfully transitioned after only a two-hour training session!
• Efficiency: Scans are quick to read and, compared to other techniques, your data storage requirements are minimal.
• Patient Experience: Generally, the procedure is well-tolerated (Conners’ patients have sat and doomscrolled during their scans), and it’s relatively affordable—ca. $700 without insurance.
• Supply Chain: The necessary tracer, technetium, is easily acquired.

Cons:

• Sensitivity & Radiation: MBI is slightly less sensitive than MRI and requires an injection and radiation exposure.
• Hardware Hurdles: Implementation requires the purchase of a dedicated breast imaging camera. The market for these vendors has historically been “unstable and volatile,” posing a barrier to entry.
• Intervention Gap: While MBI-guided biopsy exists, it is not yet widely available for follow-up.

RadFYI: MBI offers a high-yield, oncologist-approved supplemental screening option that is easy to read and patient-friendly—provided your facility can navigate that initial equipment investment.

Placenta accreta spectrum (PAS) occurs when the placenta adheres to or invades the myometrium. Its incidence has risen sharply since the 1980s, primarily driven by the increasing number of C-section deliveries. Moreover, ca. 80% of PAS cases also involve placenta previa in the affected area.

Pearls: As Cara Connolly, MD, remarked during “Mistakes to Avoid in Obstetric Ultrasound” at ARRS 2026, differentiating the exact degree of invasion on US is incredibly difficult. To wit, clinicians should prioritize identifying these key markers:

• High-Flow Lacunae: Irregular hypoechoic spaces creating a Swiss cheese or moth-eaten appearance.
• Myometrial Thinning: A loss of the normal hypoechoic zone between the placenta and myometrium or a general decrease in retroplacental thickness.
• Color Doppler: These placental spaces will fill brightly with signal, indicating high flow.
• Invasion Signs: In cases of percreta, look for abnormalities at the bladder and uterine interface.

Pitfalls: Obstetric US is highly susceptible to errors involving terminology, artifacts, as well as misinterpreting normal variants or mimics. Dr. Connolly emphasized that understanding these mistakes is crucial for interpreting exams conducted off-site or in low-volume centers. Focus on the placenta and cervix during the second and third trimesters.

RadFYI: Whereas US remains steadfast for primary screening, MRI should be utilized as a problem-solving resource when your US findings are inconclusive or complex.

Participation in youth sports is surging, and elbow injuries have nearly doubled since the 1970s, with 31% of youth baseball players now experiencing pain annually. Because pediatric growth plates are weaker and less elastic than tendons or ligaments, they are the primary site of failure when subjected to the repetitive torque of overhead motions.

Full Count: “Little League elbow” is a clinical catch-all for a spectrum of overuse injuries. The most common manifestation is medial epicondyle apophysitis, an injury occurring during the acceleration phase of pitching when valgus stress creates significant medial traction.

During his own ARRS Annual Meeting presentation on upper extremity trauma in peds populations, Vivek Kalia, MD, chair and medical director of radiology at Scottish Rite Children Hospital in Dallas, TX, noted the following key clinical presentations:

• Gradual Onset: Typically, athletes report a steady decrease in pitch velocity and localized pain over the medial epicondyle that worsens with activity.
• Overuse Mechanism: It’s heavily aggravated by inadequate rest (i.e., high pitch counts).
• Acute or Chronic? Whereas apophysitis is a chronic stress injury, a single high-force event can lead to an acute medial epicondyle avulsion fracture.

Additionally, Dr. Kalia’s play calling here prioritized comparing the symptomatic elbow to the contralateral side to identify subtle abnormalities.

• X-ray: Look for a widened physis, sclerosis, and subcortical lucency of the medial epicondyle.
• MRI: This modality is more sensitive, showing diffuse marrow edema within the apophysis and potential fluid within the growth plate.
• UCL: In peds patients with apophysitis, usually, the ulnar collateral ligament remains intact, as the bone fails before the ligament.

RadFYI: Early recognition is critical to prevent long-term sequelae, like osteoarthritis. While rest and physical therapy are the mainstays of treatment, prevention through strict activity limitations, as well as pitch count guidelines, remains the most effective strategy.

When done correctly, legal consulting offers rads a significant path to income expansion, all the while providing a frontline look at how to protect their practices from, well, malpractice. For starters, as Seth Kligerman, MD, said during Financial Wellness for Practicing Radiologists and Beyond at ARRS 2026, the gig pays “very well.”

Case Review: Assessing litigation not only helps avoid both the everyday pitfalls and those liabilities you didn’t even see coming, there are moral obligations here, too. Expert witnesses often address egregious medical mistakes and can defend colleagues when care more than meets the standard. Dr. Kligerman’s playbook for expansion also includes:

• Rep > Ads: While many rads do use third-party companies, relying on word-of-mouth builds a more sustainable, higher-quality offering.
• Both Sides: Indeed, expert witnesses must be willing to review both plaintiff and defense cases.
• Peer Learning: Success requires the ability to explain the complexities of modern imaging, medical physics, advanced anatomy, etc. not for peer review, but instead to a jury of peers.
• Claptrap: Alas, there are “morally ambiguous” witnesses who’ll say whatever they’re paid to.

Fact vs. Expert: As the late Leonard Berlin noted, legally, rads remain required to testify as fact witnesses for their own cases (frequently for a nominal fee), but the expert witness role is voluntary and involves negotiated rates. Most courts won’t compel rads to provide opinions against their will, unless they possess “unique” knowledge that no other witness can provide.

RadFYI: Expert witnessing is a lucrative way to leverage specialized knowledge, but it requires a high standard for what constitutes malpractice, as well as one’s own willingness to navigate ethical and legal entanglements alike.

The split scar sign, first described in 2020, is a powerful predictor for sustained complete clinical response and pathological complete response in rectal cancer patients following treatment.

Bio Marker: The split scar sign helps rads identify patients who have responded exceptionally well to therapy—often preventing the overcalling of residual tumor. And as Professor Kirsten Gormly of the Royal Australian and New Zealand College of Radiologists (RANZCR) illustrated during the ARRS 2026 Global Partner Society Course, to determine if a split scar sign is positive, simply use the continuous line rule:

• Positive—If you can draw a continuous thin inner black line over the scar with a marker (or “texter” as it’s called down under) without lifting it off the image, the sign is present.
• Negative—If you have to lift that marker texter, or if the scar is so thick it requires a bigger texter, the sign is in absentia.

Additional features from ARRS and RANZCR’s Rectal MRI: Best Practices from Ocean to Ocean to further set straight the split scar sign:

• Inner Winner: The most critical component is the continuous thin inner scar.
• Optional Outer: Whereas this sign is so named for its split look, you don’t always need an outer scar, especially if the original tumor was not T3.
• Virtue Signals: Look for intermediate signal in the central muscle and the potential for mucinous degeneration (i.e., higher signal) or perforating vessels to be present within the layers.
• Black Mass: The black layers on MRI represent submucosal collagen and fibrosis merging with muscle cells.

RadFYI: Misinterpreting these thin scars as residual tumor is a common pitfall. Mastering this T2 assessment allows for more accurate posttreatment restaging and better informed clinical management.

Here in our personalized cancer care era, accurate staging and imaging are foundational for optimal treatment recommendations. Radiation oncologists are increasingly dependent upon diagnostic rads for precise identification and enumeration of metastatic disease to guide that therapy.

The Magic Word: As Christopher Straka, MD, noted in the ARRS Online Course Radiation Oncology for the Diagnostic Radiologist, many patients are managed primarily by medical oncologists—who may only trigger a referral to a rad onc if they see the specific term: oligometastatic.

So, to open up the black box of rad onc and improve outcomes, Dr. Straka shared some suggestions:

• Enumerate: Provide a clear count of metastatic sites in your impression.
• Prostate-Specific: For PSMA PET scans, specifically enumerate the number of extra-axial metastases.
• Resolve Equivocals: If a lesion is uncertain, don’t just call it equivocal; please suggest the next modality that would provide more certainty.
• Breadcrumbs: Use arrows, annotations, and slice numbers to help rad oncs quickly locate targets.

RadFYI: Effective communication between rads and treating oncs has never been more important for metastasis-directed therapy. Ultimately, for the complex cases, direct consultation is still everyone’s best bet.

Posterior shoulder dislocations are notoriously difficult to spot, often described as clinically and radiographically occult. In fact, misses are so common, they could be called, colloquially, the standard of care. Not that they have to be, however.

Manickam “Nicks” Kumaravel, team doctor for the NFL’s Houston Texans, highlighted why posterior dislocations remain so frequently missed in chest and shoulder trauma during his ARRS Annual Meeting lecture.

Glow On! On a standard AP view, look for the classic light bulb appearance of the humeral head. If a post-fall image simply doesn’t look right, voilà, that’s your cue to dig deeper.

N.B. You cannot rely on a single projection…

• Scapular Y view is the critical orthogonal projection.
• It clearly demonstrates the posterior displacement that AP can hide.

RadFYI: To avoid a miss, maintain a high index of suspicion, always verifying with orthogonal views.

Fournier’s gangrene is a rapidly progressing polymicrobial necrotizing fasciitis of the perineal, perianal, and genital regions. Because of its high mortality rate, immediate diagnosis and intervention are non-negotiable.

As illustrated by Paul Nikolaidis, MD, during the ARRS Online Course Imaging of Pathologies of Male External Genitalia, this surgical emergency typically affects middle-aged men—particularly those with risk factors like diabetes, indwelling catheters, recent surgery, or immunosuppression from cancer treatments.

• Down & Dirty? Look for dirty shadowing or ring-down artifacts caused by gas within the soft tissues, along with significant skin thickening.
• Notable Normality: The testes, themselves, usually appear normal, as the infection follows fascial planes, rather than involving the scrotal contents directly.
• Gold Map: CT comes in clutch in the ED to confirm the diagnosis and, more importantly, to show the extent of involvement for the surgical team.

Whereas imaging is vital, roughly 10% of patients will not show visible gas on initial scans; therefore, clinical suspicion must remain high (even if those classic dirty shadows are absent).

RadFYI: Early diagnosis is the only way to ensure survival. Once identified, management must include aggressive antibiotic therapy and immediate surgical debridement of all affected areas.

A 43-year-old patient in Rochester, MN, presented to Mayo Clinic’s Ceylan Colak, MD, with complex hand trauma following a snowblower accident. While multiple phalangeal fractures were immediately apparent, as Dr. Colak recounted during the ARRS Online Course Imaging of Small Joints: A Review for Clinical Practice, a comminuted thumb fracture was initially overlooked due to the severity of the patient’s way more overt injuries.

Distal Distraction: Distal phalangeal and tuft fractures are not just common; they account for nearly 50% of all hand fractures. In the setting of high-energy trauma—vis-à-vis a southeastern Minnesota snowblower injury—rads can easily fall victim to “satisfaction of search,” missing these small yet clinically significant injuries:

• Initial Findings: Multiple displaced and non-displaced phalangeal fractures.
• All Thumb: A comminuted, minimally displaced fracture of the thumb distal phalanx.
• Call Kirschner: The patient ultimately required K-wire placement for stabilization of the multiple hand fractures.

Bottom Line: When assessing a bad hand fracture, always perform a systematic check of each and every digit. Don’t let the most dramatic injuries distract you from the tuft; it’s where half of hand fractures happen.

AI-powered automation is moving upstream, shifting the focus from just lesion detection to the very beginning of the imaging process: acquisition and post-processing. Most imaging costs are tied to these upstream tasks. By automating them, Linda Moy, MD, explained at ARRS 2026, providers can improve image quality while simultaneously lowering costs and increasing operational efficiency…

• On the DL: Deep learning (DL) reconstruction tools allow for noisier or lower-resolution initial imaging that AI then transforms into high-quality images. DL algos can reduce MRI scan times by >50%—while maintaining, or even improving, diagnostic quality.
• Keep the Noise Down: AI denoising algorithms have demonstrated a 60% reduction in radiation dose, alongside a 39% reduction in image noise.
• Table for 3D? Using three-dimensional ceiling cameras and infrared imaging to automate table height and positioning can save 32 seconds per exam, as well as reduce radiation dose by some 20%.
• No Contrast: Synthetic AI images can now simulate contrast-enhanced MRI, without actual contrast agents. This is a breakthrough for pregnant patients, those with severely impaired renal function, or populations concerned about gadolinium deposition.

These advancements significantly improve the patient experience, particularly for peds patients who may no longer require sedation, and claustrophobic patients who benefit from shorter time in the scanner.

Mind the Mirage: Rads must remain vigilant regarding AI “hallucinations.” While rare, these tools can occasionally invent lesions that do not exist or remove true lesions during the reconstruction process.

Bottom Line: AI reconstruction works seamlessly in the background to provide higher signal-to-noise ratios and reduced artifacts, allowing rads to focus on downstream diagnostic tasks with better data in less time.

When rads encounter symmetric macroscopic fat in the perirenal space, the initial instinct is often to fear well-differentiated liposarcoma or lymphoma. Distinguishing these from benign extra-adrenal perirenal myelipoma is critical to avoiding unnecessary clinical anxiety and aggressive surgical intervention.

Impressive Abs! In this excerpt from the ARRS 2026 Challenging Abdominal Cases Instructional Course, Cooky Menias, MD, presents a patient with abdominal bloating who revealed a symmetric retroperitoneal process pressing on the kidneys. Despite the lack of subcutaneous fat, the patient exhibited significant intra-abdominal fat that really impressed on the renal parenchyma.

The Diagnosis:

• Extra-adrenal myelipoma is a rare, benign mesenchymal tumor composed of fat and hematopoietic cells.
• They typically appear in the 5th to 6th decades of life.
• The most common extra-adrenal locations are the perirenal and presacral spaces.

The Pearls:

• Fat Chance: Unlike perirenal fibrosis (IgG4-related disease) or Erdheim-Chester, which encase the kidneys and lack fat, myelipomas contain macroscopic fat and embed (i.e., “impress”) upon the renal tissue.
• PET-CT Utility? While not diagnostic, PET-CT can be reassuring by showing a lack of significant uptake, helping to rule out high-grade lymphoma or aggressive malignancy.
• Stress Test: These tumors may arise from ectopic adrenal tissue or reticular endothelial cells that become exuberant during chronic stress, endocrine dysfunction, or inflammation.

Bottom Line: If you see symmetric macroscopic fat embedding the kidneys in an older patient with low metabolic activity on PET, think extra-adrenal myelipoma. While biopsy (even open biopsy) may be required for definitive comfort, recognizing this embedding fat pattern can narrow the differential significantly.