Author: Logan Young

Summary: Rushing to definitives on imperfect studies leads to cognitive errors, overcalling, and inappropriate assignment (e.g., BI-RADS 3 should never be assigned at screening; baseline findings with incomplete evaluation require BI-RADS 0 for additional workup).

Mastering Mystery: An unknown diagnosis does not equal an unknown process; you needn’t know the precise pathology to determine your safest next step. Introduced by ARRS Distinguished Educator Dr. Tanya Moseley during our Mystery to Mastery longitudinal course, here’s how her C-L-E-A-R acrostic’s stepwise methodology transforms clinical uncertainty into structured reasoning:

• C—Context: Anchor in Facts
  • Gather patient age, symptoms, indication, modality, technique, priors, etc.
• L—Localize: Boundaries, First
  • Pinpoint an abnormality’s region, compartment, and epicenter, before attempting to characterize it.
• E—Examine: Objective Descriptions
  • Systematically evaluate morphology, density, echogenicity, or enhancement, then document key negatives.
• A—Alternatives: Defensible DDX
  • Avoiding the too obscure, rank 2–3 reasonable possibilities (summation artifact vs. focal asymmetry vs. obscured mass).
• R—Resolve: Execute Safely
  • Determine whether the patient needs FFDM, DBT, targeted US, prior comparison, or even reassuring observation.

Case in Point: Single-View Asymmetry

• Scenario: In Moseley’s case, a baseline screening mammogram in an asymptomatic patient revealed a focal density in the middle posterior left breast, visible on only one view.
• Reasoning: Persistence, morphology, and second-view correlate couldn’t be confirmed.
• Action: Incomplete exam assigned BI-RADS 0 and recommended mammo, DBT, and US—rather than guessing or misapplying BI-RADS 3.

Summary: Before diagnosing a calcified right paratracheal lymph node or metastasis, verify whether that heavy brightness is simply transient contrast pooling inside an azygos arch venous valve.

Trapper John, MD: Got high attenuation in the right paratracheal space on contrast-enhanced chest CT? Careful. As Dr. Brent P. Little explained during ARRS26, contrast material often becomes trapped behind a normal venous valve in the azygos arch—creating a bright focal density that mimics pathology:

• Anatomy of Venous: A normal valve with two leaflets sits in the region of the azygos arch.
• Delayed Clearance: Whereas contrast washes out from the rest of the thoracic vasculature, stagnant contrast trapped behind the valve leaflets can remain for several minutes.
• It’s Not Unusual: Trapped contrast presents in the right paratracheal space with a distinct gestalt (sometimes demonstrating a subtle fluid/contrast level).
• The Pit: In patients with calcifying malignancies, this high-density contrast retention can be wrongly suspected as a calcified metastatic node.

Summary: Pairing artifact-reduced imaging with consistent, rad-forward language helps hone reportage that can effectively guide surgical decision-making.

Particle Problem: All functional joint arthroplasties create wear particles that can trigger a host immune response, leading to inflammatory tissue damage around hardware. Because terminology describing these soft-tissue abnormalities is used inconsistently across literature and practice alike, as Dr. Jeremiah R. Long reminded us during ARRS26, clarity is critical:

• Quality Control: Implement metal artifact reduction techniques across both CT and MRI to better detect and characterize lesions.
• A Priori Advantage: Track lesion size and progression over time to assist surgeons in determining whether/when to revise.
• Clinical Context: Query the EMR for history, labs, operative details, etc.
• Imaging-Centric Language: Utilize “umbrella terms” appropriate for the specialty—pseudotumor and adverse local tissue reaction (ALTR), specifically.

Jettison the Jargon: Dr. Long suggested that we refrain from using gross, intraoperative, or pathological terminology, à la metallosis or trunnionosis.

RadFYI: Portal venous gas is one of the most critical catastrophes that can develop as a result of pneumatosis, so do call on the classics here: branching lucencies within the liver.

Not Nothing: Reading neonatal abdominal radiographs straddles that line between the overly sensitive “call me, maybe” and the specific and definitive. As Dr. Andrew T. Trout reminded us during the ARRS Online Course Radiology Case Review – Pediatric Imaging, calling pneumatosis is not a benign diagnostic event.

• Usually, a positive read prompts clinicians to rest the baby’s gut, make them nothing by mouth, and initiate total parenteral nutrition.
• Since such interventions carry their own risks, prioritize specificity over hypersensitivity.

Clear-cut cases present with obvious intramural collections of linear or curvilinear gas across multiple loops…or the presence of portal venous gas!

• Trout’s Tip: Do not call pneumatosis unless you see clear, indisputable intramural lucencies (either linear or curvilinear) in the context of other concerning clinical findings.

Grey Zone: When faced with subtle, bubbly lucencies in the hemi-abdomen, obtaining a delayed, follow-up radiograph is a highly reasonable and helpful strategy. Over time, true pneumatosis will progress to show more convincing, clearly intramural curvilinear lucencies on a delayed radiograph.

Summary: Any contralateral mediastinal nodal metastasis or any supraclavicular/scalene adenopathy remains classified as N3, regardless of the primary tumor location.

Station to Station: One of the most notable updates to the 9th edition of the TNM staging system for lung cancer is the formal subdivision of N2 disease: N2a *and* N2b. According to Dr. Girish Shroff’s update in our Cardiothoracic Imaging Case Review Online Course, the priority of now is the number of involved nodal stations, rather than absolute count of metastatic nodes:

• N0: No regional lymph node involvement.
• N1: Metastasis in ipsilateral bronchopulmonary or hilar nodes.
• N2: Metastasis in ipsilateral mediastinal and/or subcarinal nodes, now subdivided by station density:
  • N2a—Involvement of a single N2 station.
  • N2b—Involvement of multiple N2 stations.
• N3: Metastasis in contralateral mediastinal or contralateral hilar nodes, or any supraclavicular/scalene nodes.

Stations > Counts: Even if a patient presents with multiple metastatic nodes, they are staged as N2a if all involved nodes reside within a single station (e.g., lower right paratracheal region).

• Metastatic involvement of both station 5 and station 6 automatically elevates to N2b.

Summary: If it’s the patient’s first presentation, and your MRI findings remain ambiguous, the safest bet here is follow-up US in 2-3 months to confirm whether that suspect cyst has resolved.

On GYN MRI, both of these adnexal pathologies present with pelvic pain and may exhibit T1 hyperintensity. Whereas hemorrhagic cysts are generally self-limiting and resolve, as Dr. Milana Flusberg distinguished during ARRS26, the markers of chronic endometriosis can lead to scarring and pelvic tethering, as well as rarer complications like infection.

Three T2 Tells: Look out for these specific T2-weighted signs to help you differentiate:

• Shading: This classic feature—where a T1-hyperintense lesion appears hypointense on T2-weighted sequences—is highly characteristic of endometriomas. However, it is not 100% definitive, as it occurs in just under 20% of hemorrhagic cysts, too.
• Dark Spot: Referring to focal, highly T2-hypointense hemosiderin spots inside an otherwise mildly hypointense or intermediate lesion, this one is highly specific for endometrioma, albeit lacking high sensitivity.
• Hypointense Rim: A peripheral hemosiderin ring caused by repetitive, cyclical bleeding, it’s more common in endometriomas, although it can sometimes be seen in hemorrhagic cysts.

Beyond the Cyst: Quite often, Flusberg said, the most helpful clue lies outside the lesion, itself:

• Deep Pelvic Endometriosis? Look for T2-hypointense pelvic fibrosis tethering the mass to adjacent structures, such as the rectal wall.
• Multiple Lesions? Finding many complex adnexal lesions strongly points toward endometriosis, rather than an isolated hemorrhagic cyst.

Is There an Echo in Here? If you’ve got prior or concurrent US, the classical hemorrhagic cyst demonstrates “lace-like” reticular internal echoes or angular, concave retractile clots. Meanwhile, endometriomas typically present with homogeneous, low-level internal echoes.

Summary: Just last week, a federal court ruled that the government’s methodology for crunching QPA is, at least partly, unlawful. However, a majority of the 5th Circuit’s 17 active judges agreed that agencies can allow insurers to use existing QPAs until new ones can be calculated, meaning that NSA’s dispute resolution process can continue unabated.

Reimbursement Check, Mate? A loophole in the implementation of the No Surprises Act (NSA) allows health insurers to use inactive, unnegotiated “ghost rates” to artificially depress reimbursement benchmarks for out-of-network care.

In the second episode of the AJR Podcast Series Difficult Conversations, Richard E. Heller III, MD, MBA, explained to co-hosts Sherry S. Wang, MBBS, and Surbhi Raichandani, MD, how this loophole unfurls:

• Boilerplate: Insurers issue massive, standardized contracts containing thousands of billing codes to every practice they contract with.
• Ignorance: Rads ignore psychiatric codes, while psych or family medicine practices ignore complex MRI and CT scans because they will never perform or bill for those services.
• Paper Tigers: Insurers slip rock-bottom default rates (such as paying 60% of Medicare) into these ignored codes. Because they are signed into contracts but never actually billed, they exist purely on paper.

Median Distortion: The NSA relies on the Qualifying Payment Amount (QPA)—the median commercial rate for a service—to guide out-of-network payment arbitration.

• Artificial Depression: Insurers have been allowed to calculate the QPA using any contracted rate on their books, regardless of how often it is actually billed. Including zero-utilization ghost rates skews the median rubric downward, making that benchmark highly unrealistic.

Black Box Computation: When physicians ask insurers to show the math or the range of contracts used to calculate these low QPAs, amazingly, insurers refuse. Providers are forced to simply take the insurers’ word that the calculations are correct.

• What Oversight? To date, one, singular federal audit of QPA calculations has been publicly known. Not unsurprisingly, it uncovered irregularities.

Summary: Explicitly advise additional imaging to find the underlying cause, once the blood has cleared. If your initial CT reads negative, yet suspicion remains, repeat the study later or escalate to angiography…especially if it’s vasculitis you suspect.

Clear Call: Quite quickly, Wunderlich syndrome—spontaneous, non-traumatic bleeding confined to the perinephric space—becomes life-threatening. When a patient presents with sudden flank pain, a palpable tender mass, or signs of hypovolemic shock, perinephric hematoma ID is merely your opening move.

• Root Cause: Staggeringly, 60% of these patients have an underlying renal mass, ranging from benign angiomyolipomas to renal cell carcinomas (RCC).
• Other Culprits: If there’s no mass, etiology may stem from vasculitis, arteriovenous malformations, anticoagulation complications, or cystic renal disease.

Ultimately, you can’t rely solely on that initial emergency scan to rule out pathology, Dr. Myra Feldman said during the ARRS Online Course with SRU Sound the Alarm! Emergency and Pitfall Cases in Ultrasound.

• Half-Sensitive: CT’s sensitivity at the time of an acute hemorrhage is only 57%.
• Masking Effect: Dense, acute blood products can easily obscure the underlying lesion.

So, what’s a rad to do? Don’t let this go undiagnosed. The reading room’s next best step: calling the ordering physician to report the hemorrhage.

Summary: MRU is indeed invaluable when you want to avoid ionizing radiation, à la pregnant patients. But it should be leveraged, too, as an essential second-line problem solver for atypical renal and urothelial masses.

GU Pro: Sure, CTU remains the daily, fast, first-line workhorse for genitourinary imagers. Still, standard scans can struggle to characterize atypical tumors or complex tissue changes. Enter, then, multiparametric MR urography, offering multi-layered tissue characterization to narrow your DDX.

By combining multiple specialized sequences, Dr. Myles Taffel noted during our longitudinal course Mastering Genitourinary Imaging & Interventions, MRU allows rads to analyze pathology from several angles across distinct terrain:

• T2-Weighted Anatomy: Delivers detailed structural imaging comparable to what is obtained with CT.
• Multi-Phase Contrast: Captures multiple enhancement phases, including early dynamic post-contrast and late urographic phases, which may not be feasible on CT.
• DWI: Highlights cellular diffusion restriction to pinpoint exact areas of pathology.
• Intrinsic T1: Provides native tissue contrast to further assist in detailed characterization.

As Taffel recalled, the real utility of MRU’s multiparametric sequences shines in those really tough cases, including off-roaders:

• ID Lymphoma Mimics: A renal hilum mass can mimic standard urothelial cell carcinoma. However, when MRU shows the mass extending along the ureter without significant hydronephrosis—coupled with restricted diffusion on DWI—the diagnosis of lymphoma becomes clear.
• Bladder Subtleties: In a patient presenting with hematuria, a standard T2 sequence might only show vague bladder wall enhancement. Adding DWI and early dynamic post-contrast sequences provides the high-contrast resolution needed to confidently pinpoint exactly where the malignancy lies.

Summary: Succeeding in this arena requires exceptional diagnostic accuracy, collaborative trust, and the discipline to filter out the noise. As Dr. Beaulieu put it: “Call it tight, but call it right.”

Any Given Monday: Behind every highly-paid professional athlete lies a high-pressure team of professional physicians, all navigating a legion of legal liabilities and communication protocols. For rads, specifically, your interpretation can dictate whether a franchise player is cleared, placed on injured reserve, or even cut from the roster.

During a recent episode of the AJR Podcast Extreme Radiology, Dr. Chris Beaulieu—who spent some two decades consulting for the NFC West’s own San Francisco 49ers—shared how pro-sports imaging is often an entirely different ballgame from standard practice:

• Liabilities Galore: Unlike typical malpractice caps, pro liability scales both wildly and widely to cover a star’s lost career wages. Active lawsuits can easily range from $50-$150 million.
• Monday Morning MRI: Whereas stadium x-rays for fractures and dislocations are interpreted midgame by team orthopedists, the rad’s sprint begins Monday morning, including dedicated slots to stage and grade acute joint, muscle, and cartilage injuries.
• Bad Call! Rads must resist the urge to overcall non-acute incidentals. Noting “every molecule of water, ” as Beaulieu said, needlessly triggers phone-tree panic among agents, coaches, and if you’re unlucky, the media.

Astroturf War: Due to the extreme risk of misinterpretation, rads are highly discouraged from communicating directly with players, coaches, and agents especially. Instead, they maintain a strict, uniform reporting pipeline directly to the head athletic trainer and/or team orthopedic surgeon.

• Pro Peer Review? Quite frequently, an agent will demand second, third, or fourth opinions to protect their clients’ earning potential. A single player’s scan is often peer-reviewed by up to 5 different experts before final consensus.

Summary: From benign solid nodules to active, AFTNs, thyroid RFA delivers excellent clinical outcomes, significant volume reductions, and functional recovery with minimal patient downtime.

RFA in the USA: Thyroid radiofrequency ablation offers an effective alternative to surgery or radioactive iodine—relieving cosmetic or compressive symptoms and normalizing function without the risk of lifelong hypothyroidism.

Approach & Technique: As Dr. Frank Hao explained during ARRS’ Emerging IR Treatments Online Course, operators utilize a trans-isthmic approach and the moving shot technique to systematically and safely ablate the tissue.

• Agents of Shield: To prevent complications, clinicians must identify and avoid what Hao dubbed the “danger triangle,” protecting critical structures like the recurrent laryngeal nerve, vagus nerve, and cervical sympathetic ganglion.
• Staged Ablations: For exceptionally large nodules, staging the treatment across multiple sessions keeps patients comfortable and prevents lidocaine from wearing off during a tedious procedure.

By the Numbers:

• 90%: Volume reduction rate achieved in a year for a very large mixed cystic nodule in Hao’s case, resulting in complete resolution upon physical exam.
• 40-91%: Rate of TSH normalization in patients treated for autonomously functioning thyroid nodules (AFTNs), allowing patients to completely stop thyroid-regulating medications like methimazole.
• <12 cc: Volume threshold below which hot nodules have a significantly higher chance of achieving a euthyroid state post-RFA.

Summary: By marrying your findings with patient demographics, you can construct a highly focused DDX before ever sending the patient for cross-sectional imaging.

Full Felson: Evaluating the mediastinum is one of the most challenging aspects of reading chest radiographs because, well, masses are relatively rare. One of the biggest interpretive pitfalls? Glancing at a featureless mediastinum, seeing clear lungs, and calling the exam normal. Erroneously, of course.

During the ARRS26 honorary lecture celebrating Diane C. Strollo, MD, Melissa Rosado de Christenson, MD, detailed how rads can systematically characterize lesions and navigate classic compartments:

• Focal, or Diffuse, Lesion? Determine if a mass is focal, diffuse, or even multifocal.
  • Diffuse, bilateral mediastinal enlargement that obscures normal anatomical landmarks typically indicates an aggressive lesion or lymphadenopathy.
  • Unilateral, focal masses suggest a primary lesion, à la neurogenic neoplasm.
• Recognize the Landmarks: You gotta know your normal lines, stripes, and interfaces—right paratracheal stripe, anterior junction line, azygo-esophageal recess, etc.—to definitively ID if a mass is present.
• Read the Classics: Leverage signs like the hilum overlay and cervicothoracic signs to accurately locate abnormalities.
• Paging Dr. Felson! Though modern CT uses classifications like prevascular and visceral compartments, Felson’s anterior, middle, posterior compartments remain highly effective for narrowing differentials.