Author: Logan Young

Summary: In the peripheral zone, DWI is king. If the diffusion is markedly restricted and the lesion is over 1.5 cm, indeed, it’s PI-RADS 5.

For clinically significant prostate cancer, understanding which sequences drive what scores is essential for accurate diagnosis and effective patient triage. In July’s session of our year-long Mastering Genitourinary Imaging & Interventions course, Dr. Nilda Maria Williams explained that PI-RADS v2.1 standardizes identification by utilizing specific “dominant” sequences based on the lesion’s anatomical location:

• Peripheral zone: Score is primarily driven by DWI.
• Transitional zone: Score is driven by T2W imaging.
• Limited DCE: Dynamic contrast enhancement plays a specific role—upgrading PI-RADS 3 to 4 in the peripheral zone.

5 on 5: Again, in the peripheral zone, a DWI score of 5 automatically results in a PI-RADS 5 assessment—regardless of T2W findings or enhancement. Criteria for this top-tier score include:

• Marked restriction: Lesion must be markedly hypointense on ADC and markedly hyperintense on high b-value DWI (i.e., darker and brighter than any other focus in that zone).
• Size threshold: Lesion must be >1.5 cm in its greatest dimension.
• Aggressive features: Evidence of definite extraprostatic extension also warrants a PI-RADS 5.
• T2W appearance: Typically, these lesions present as circumscribed, homogenous, moderately hypointense masses.

Summary: Whereas the specter of a suit is a sorry reality in today’s litigious environment, meticulous reporting strategies significantly lower your risk of being named a defendant.

Trigger Warnings: Mostly likely, it’s in your report—that primary opportunity to document, contemporaneously, your own thought process. As defense attorney Victoria Scanlon pointed out at ARRS26, radiology ranks as the sixth most commonly sued specialty. And with nuclear verdicts now seeing settlements in excess of $10 million, the radiologist’s report is often the deciding factor in a successful malpractice defense.

The Best Offense? Increased access and ever-increasing workloads (no thanks to AI!) help foment a higher-risk environment for error. Be it an honest mistake in transcription or more epic fail to compare your findings with a priori imaging, Scanlon suggested writing more defensively:

• Know your audience—juries are composed of laypeople, not docs. Keep impressions and recommendations jargon-free, so they’re clear to referring providers, patients, and even legal panels
• Provide timelines—when recommending follow-up, always include an explicit timeframe to prevent that rec from falling through the cracks
• Document direct contact—should you speak with a provider, affirmatively document to whom you spoke, what was said, date/time, etc. Because plaintiff attorneys love to argue: ‘If it wasn’t documented, it didn’t happen.’
• Be assertive—avoiding passive terminology, answer the clinical question clearly, concisely, and unambiguously
• Proofread—grammatical and spelling errors make you look “sloppy and uncaring” Scanlon said, forcing you to defend the typos rather than your expertise

Summary: Optimal preparation relies on two pillars: achieving euglycemia to prevent competitive inhibition and maintaining basal-only insulin levels to avoid tracer diversion to muscle.

Sugar, Sugar: Both hyperglycemia and insulin exposure degrade [18F]FDG PET image quality, although they do so via distinct physiologic mechanisms that require different management strategies.

Understanding that difference is critical. And as Phil Mulugeta, MD, reminded us in a recent AJR Expert Panel Narrative Review, the insulin effect is often more detrimental to a scan than the hyperglycemia, itself.

The Competition—Hyperglycemia

• Mechanism: Elevated serum glucose levels compete directly with FDG for cellular transport via glucose transporter (GLUT) proteins and phosphorylation by hexokinase.
• Impact: This competitive inhibition reduces tumor-to-background contrast and can lower SUVs in tumors and the brain.
• Silver Lining? Despite high glucose, tumor FDG uptake often remains robust enough for accurate visual interpretation, especially at levels below 200 mg/dL.

The Diversion—Insulin Effect

• Mechanism: The presence of short-acting exogenous insulin or endogenous insulin, triggered by a recent meal, upregulates GLUT-4.
• Impact: Mulugeta et al. note that this “shunts” the injected FDG into skeletal muscles and the myocardium, diverting it away from potential malignancies.
• Danger! This effect can render a scan completely non-diagnostic—even when the measured blood glucose level appears acceptable
  • A patient scanned 1.5 hours after eating could show a false negative, due to diffuse muscle uptake masking hypermetabolic metastases.

The Trap: Administering correctional insulin immediately before a scan in an attempt to fix hyperglycemia often backfires. Sure, it’ll lower the sugar number, but it triggers the far more damaging insulin effect, resulting in abnormal tracer biodistribution.

• The Consensus: If correctional insulin must be used for levels >300 mg/dL, it should be administered subcutaneously (never IV!) with a mandatory 4-hour delay before FDG injection to allow the insulin effect to subside.

Summary: Rads reviewing their peers does have its limits. Implementing structured feedback from referring physicians is a novel approach to identify problems that typically go unnoticed, such as confusing terminology and poor clinical correlation.

21st Century Rad: Thanks, in part, to the 21st Century Cures Act, what was once a memorandum of understanding between clinicians has quickly become the primary fount of information for patients and referring physicians alike.

During his ARRS26 presentation, Yale emergency rad Jonathan Mezrich, MD, denoted what your typical patient can—and can’t—decipher:

• Plain anatomical terms (right knee), simple descriptions (mass, fluid), and clear action language (biopsy recommended) are definite yeas.
• Jargon such as “Hounsfield units” or “restricted diffusion” are meaningless nays to laypeople.
• Avoid Latin (e.g., hepatomegaly or pneumothorax) when simple will suffice.
• “Negative” or “unremarkable” are often misinterpreted; patients clock “negative” as a bad thing, whereas “unremarkable” sounds dismissive, rather than normal.

A Tale of Two Readers: Today, some 44% of patients read their imaging results before speaking to the ordering provider. Meanwhile, referring physicians frequently identify unclear language, typographical errors, and failure to answer the clinical question as top reporting issues. Adding that seemingly small errors like typos can cause consternation for end-readers, Mezrich added to his list accordingly:

• Target a sixth to eighth grade reading level to maximize comprehension and reduce anxiety.
• Top load your impression or summary statement, so no one has to go hunting.
• Is a finding benign? Say so explicitly to prevent unnecessary worry.
• Ensure the report directly addresses the concern that prompted the study.
• Referring physicians find a rad’s recommendations clinically useful and often want more guidance than they currently receive.

Summary: FAST’s future is in artificially deep reconstruction. Tech à la AIR Recon DL or Deep Resolve allows for even higher acceleration factors and noise reduction, perhaps slashing times further without sacrificing the quality required for ED triage.

Time Is Tissue: Trad MRI’s exam time too often limits its use in emergent settings. Focused Abbreviated Survey Techniques (FAST) protocols put time back on the clock. Fomenting rapid inclusion/exclusion of life-altering conditions, FAST helps make confident decisions sans the comprehensive scan’s half-hour wait.

• Stroke: Uses abbreviated sequences—with or without contrast—to detect acute ischemia and large-vessel occlusions.
• Spine: Screening tool for cord compression that can be completed in sub 20 minutes, versus 90 minutes for a total spine protocol.
• Peds: Motion-robust, non-sedated approach for monitoring shunted hydrocephalus or evaluating fluid-filled regions in ca. 4 minutes or less.
• EPIMix: Ultra-fast, 1-minute full-brain exam that provides multiple contrasts (T1, T2, FLAIR, DWI) simultaneously.

More Than Magnets: Success needs more than speed. As Dr. Laura B. Eisenmenger detailed in our Implementing FAST MRI Protocols Online Course, truly iterative implementation takes a dedicated kind of buy in:

• Clinicians must be on board with targeted exams, rather than comprehensive ones for specific indications.
• Utilizing dedicated ED scanners and radiology-specific transporters has been shown to significantly reduce order-to-first-image times.
• Staff turnover may mean yearly education to maintain efficient throughput and culture.

Summary: Ultimately, the positive/negative dichotomy just isn’t enough anymore. The Centiloid scale nurtures the nuance necessary for personalized treatment, as well as therapeutic response over time.

At Scale: Visually reading amyloid PET is too qualitative. Enter, then, the Centiloid scale, a quantitative tool that provides the precision necessary for selecting and monitoring patients on new disease-modifying therapies.

Standard Yardstick: With Alzheimer’s diagnostics bracing for more biomarker-based frameworks, amyloid PET has been dubbed “core 1,” capable of detecting pathology long before symptoms emerge. And as Dr. Lawrence Tanenbaum trumpeted during Imaging of Dementia and Alzheimer’s Disease: What You Need to Know, the Centiloid scale harmonizes results across different PET tracers and imaging centers—creating a single, site-agnostic measure of brain β-amyloid burden.

• 0: Mean uptake of healthy, amyloid-negative controls.
• < 10: Reliably negative.
• 10–30: Intermediate zone, where this “sweet target” population may represent the earliest detectable amyloid changes.
• 21–24: Threshold often used to maximize agreement with traditional visual interpretations.
• > 30: Reliably positive.

Moreover, immunotherapies like Lecanemab and Donanemab require longitudinal tracking to prove target engagement and confirm amyloid clearance. Tanenbaum reminds us, too, that some therapies were paused once a patient’s Centiloid score dropped below a specific threshold.

The Catch? Sure, quantification helps less-experienced readers identify ambiguous or borderline cases. Nevertheless, visual confirmation remains essential. Automated Centiloid scores can be “fictitious” or inaccurate if there is motion, significant brain atrophy, or atypical tracer uptake in the cerebellar reference region.

Summary: A standardized MRI protocol—evaluating the device in both inflated and deflated states—remains the gold standard for assessing integrity. To wit, Aswani’s own reporting template ensures a comprehensive evaluation of the glans, shaft, and proximal components, leading to more consistent patient outcomes.

Killer Crossover: As the prevalence of erectile dysfunction rises, so, too, do penile prostheses. For rads, accurately identifying normal device anatomy versus critical complications is essential for guiding patient care. As Yashant Aswani, MD, pointed out in the ARRS Online Course Imaging of Penile Implant, Gender-Affirming, and Cosmetic Surgeries, typically, complications are tripartite:

Cylinder

• Size Matters: Oversized implants can cause buckling; undersized cylinders may result in a floppy glans.
• Travel Plans: Cylinders can migrate laterally, proximally, or distally.
• The Crossover: AKA “medial migration,” this occurs when a cylinder perforates the septum. (You may see two cylinders in one compartment, although the other cavernosa appears empty.)

Reservoir/Pump

• Ectopic? It’s vital to distinguish true herniation or migration from deliberate ectopic placement by checking the patient’s surgical history.
• Cosmesis: Migration is often a cosmetic concern, but rads should still note its position.

Mechanical & Post-Op Risks

• Wear ‘n’ Tear: Look for signs of aneurysmal dilation or actual fractures of the implant.
• Infection: Commonly seen as soft-tissue abscesses or scrotal hematomas.

Summary: No need to reinvent the wheel here. Utilize SIR templates to automate all the jargon, allowing you to keep your impression section clear and concise for both patients and referring clinicians alike.

Early Interventions: In our declining reimbursement era, accurate documentation is really the best way to ensure your practice remains sustainable. Coders can only bill for what you, the rad, explicitly reports. And if it isn’t there, as Sean Golden, MD, detailed during ARRS26, you aren’t getting paid for it.

1. Moderate sedation’s magic words—most IR procedures use sedation, but you can’t simply state “moderate sedation was performed.”

• Document presence of “independent trained observer,” continuous monitoring occurred, you were present for first bolus, and that you spent specific face-to-face time. And it’s “moderate” only if you use a benzodiazepine/opioid combo.

2. Vascular US guidance is on volume—billing CPT 76937 for access might only pay ~$10, but failing to claw that back across a high-volume practice can cost tens of thousands annually.

• Note vessel patency, real-time visualization of needle entry, and that a permanent image was stored.

3. Don’t Forget Diagnostic Angiography! Quite often, you can bill for the diagnostic portion of a procedure if your decision to treat was based on those images.

• Log one of four of the following: no prior study available, patient’s condition changed since last study, prior study was inadequate, or clinical change occurred during procedure. [N.B. One cannot bill for simple “roadmapping.”]

4. Capture selective catheterization—In many cases, you can bill for the physical work required to get the catheter into a specific artery, in addition to the treatment code (e.g., embolization).

• Use templates that include “vessel catheterized” and “findings” sections to ensure codes are captured.

5. Add on with care…

• Cone beam CT: Record that images were sent to workstation for 3D rendering under physician supervision.
• Modifier 22: Reserve for the top 1% of difficult cases to increase reimbursement by 20-30%. Physician,  prepare thyself for manual review—detailing exactly why this case was substantially harder than typical.

Summary: Ultimately, GTC transforms breast US from a tool used primarily for lesion characterization into a quantitative framework for personalized risk stratification vis-à-vis improved multidisciplinary communication.

Three-Ps: The BI-RADS Version 2025 update introduces a big sonographic innovation: glandular tissue component (GTC). Whereas mammographic density and MRI fibroglandular tissue (FGT) measure the overall volume of tissue, GTC provides a specific assessment of the internal composition of the breast parenchyma on ultrasound (US).

Prognostic: No longer is standardizing US tissue composition merely a descriptive endeavor. As Paola Minichetti, MD, and her co-authors from the University of Udine broke it down in their recent AJR review, it is predictive.

• Risk Assessed: Higher GTC levels are associated with increased breast cancer risk, as well as higher abnormal interpretation rates during supplemental screening ultrasound.
• Clinically Consistent: GTC moves US away from purely qualitative “habit-based” reporting toward a lexicon harmonized across multidisciplinary teams.
• AI at the Ready: By defining GTC formally, BI-RADS creates a structured target for future AI-driven automated quantification and objective data mining.

Percentage: GTC represents the ratio of glandular structures—lobules and terminal ducts forming terminal ductal lobular units (TDLUs)—to the total fibroglandular tissue, expressed as a percentage. Minichetti et al. categorize GTC into four tiers:

• Minimal: <25% glandular tissue (predominantly fibrous)
• Mild: 25–49% glandular tissue
• Moderate: 50–74% glandular tissue
• Marked: ≥75% glandular tissue (the most glandular-rich category).

And for simplified reporting, these can be grouped into low GTC (minimal/mild) and high GTC (moderate/marked).

Personalized: On US, GTC is assessed qualitatively after a whole-breast scan by distinguishing isoechoic glandular tissue from hyperechoic fibrous tissue. While fibrous tissue contributes to the architecture, TDLUs represent the actual glandular component being quantified.

Summary: With DR basics forever in your own heart, do allow your head to consider alternatives—even, perhaps especially, in the middle of a trauma workup.

Incidentally: In the high-stakes environs of the ED, tis easy to mistake pre-existing pathology for acute trauma. During “Selected Head-to-Toe Topics in Emergency Radiology,” co-presented with the American Society of Emergency Radiology at ARRS26, Daniela Galan, MD, pointed out a pitfall wherein a suspected hepatic vascular injury proved merely incidental. Pretty common, too.

Nuance Needed: During the evaluation of a right hepatic lobe laceration, a focus of contrast enhancement was initially flagged as a potential contained vascular injury or active hemorrhage. However, the enhancement pattern didn’t quite fit the trauma profile:

• Tell-Tales: Dr. Galan’s lesion exhibited peripheral interrupted nodular enhancement with progressive centripetal filling.
• Gestalt? Whereas active hemorrhage increases over time, this focus was too rounded to be a typical bleed.
• Eureka! Angiography confirmed the lesion was a hemangioma…not a traumatic vascular injury.

Summary: FDG PET/CT remains reliable in patients on GLP-1 therapy regardless of their last injection date. Rather than focusing on injection timing, clinicians should prioritize maintaining appropriate blood glucose levels prior to the scan to ensure optimal brain FDG uptake and SUV accuracy.

Clockwise: As all the agonists assemble, rads have rightfully questioned whether so many GLP-1s alter FDG biodistribution. Short answer via the Best Oral Presentation Abstract in Nuclear Medicine at ARRS26: nope.

Why Wait? Concerns regarding “muscle mapping” or altered bowel uptake have led to additional uncertainty about whether patients should pause their medication or time their scans around their injection schedule. Led by Anna Eshghi, researchers from the University of Arkansas for Medical Sciences suggests such precautions are unnecessary.

Eshghi et al. retrospectively analyzed 126 patients on GLP-1 therapy, including a paired comparison of 36 patients who had scans both before as well as after starting the medication.

• Stable Biodistro: No statistically significant differences in FDG uptake were found in the liver, blood pool, skeletal muscle, or abdominal fat.
• Brain Exception: The only significant SUV change was in whole-brain SUVmean (p=0.0274), which correlated with improved blood glucose levels.
• Timing is Irrelevant: Variations in GLP-1 dosing (ranging from 0 to 10 days before the scan) did not significantly impact FDG biodistribution.
• Metabolic Trends: While mean blood glucose dropped (124.8 to 111.1 mg/dL) and BMI decreased (37.5 to 34.7), these changes did not trigger “muscle-heavy” scans.

Summary: By understanding the hospitalist’s workflow and providing clear, structured, and confident recommendations, rads provide a value-added benefit that directly improves patient outcomes.

Party Line: Hospitalist James Dreer, DO, MS, highlighted a critical gap in patient care during ARRS26: most referring providers—including PCPs, specialists, and ER docs—are *not* confident interpreting their own imaging, relying almost entirely on the rad’s expertise.

Core Requirements: Vague reporting and poor layout lead to clinical uncertainty, unnecessary phone calls, and serious patient safety risks.

• Structure is Supreme: Clinicians strongly prefer structured reports over dense narrative text to find actionable diagnoses at a glance.
• Kill the Hedge: Terms like “compatible with” create confusion. Use confident language (e.g., “highly suspicious of”) so clinicians can act decisively.
• Drop the Filler: Phrases like “please correlate clinically” are often redundant and viewed as unhelpful by internal med docs.
• Pick Up the Phone: Direct communication for unexpected or emergent findings—like an incidental pulmonary embolism—drastically lowers mortality rates.

Follow-Up Factor: To “close the loop” and prevent safety misses, rads must change how they handle recommendations:

• Section-Specific: Follow-up recs should be placed in a dedicated, easy-to-find section.
• Visibility: Hiding follow-up needs within the body of a report increases the chance they will be overlooked, leading to missed diagnoses and non-adherence.