Recent Advances in Radiodiagnosis & Imaging - MD/MS Exam 2026

1. Photon-Counting Detector CT (PCD-CT) - The Most Testable Advance

• Higher spatial resolution (down to 0.2 mm isotropic) - superior bone, vessel wall, and stent imaging
• Simultaneous multi-energy (spectral) data acquisition in a single scan
• Reduced electronic noise - improved low-contrast detectability
• Lower radiation dose via virtual monoenergetic images and noise reduction
• Reduced beam-hardening and metal artifacts
• Enables K-edge imaging for novel contrast agents (e.g., gold, bismuth, gadolinium nanoparticles)

• Cardiovascular: Coronary artery disease - simultaneous first-pass perfusion + late iodine enhancement in one scan; better stent lumen visualization; myocardial infarction characterization (overcoming the low soft-tissue contrast limitation of conventional CT) - Grainger & Allison's, p. 3805
• Neuro: Intracranial vessel wall imaging, hemorrhage characterization, improved bone-brain interface
• MSK/Rheumatology: Crystal deposition diseases (gout - urate crystal mapping), bone marrow imaging previously reserved for MRI - Firestein & Kelley's Rheumatology, p. 1131
• Abdominal: Adrenal adenoma characterization, pancreatic lesions, liver lesion perfusion
• Chest: Pulmonary embolism, lung nodule characterization

2. Dual-Energy CT (DECT) / Spectral CT

• Gout: Urate crystal mapping (green color coding) - sensitivity ~78-90%, highly specific
• Pulmonary embolism: Iodine maps showing perfusion defects
• Renal: Virtual non-contrast images; uric acid vs. calcium stone differentiation (avoids additional contrast series)
• Liver: Iodine quantification for tumor vascularity; hepatic steatosis grading
• Adrenal: Lipid-poor adenoma vs. metastasis - sensitivity 96% for adenomas on iodine maps - Grainger & Allison's
• Oncology: Tumor iodine uptake as surrogate for viability post-treatment
• Metal artifact reduction: Virtual monoenergetic images at high keV reduce prosthesis artifacts

3. Artificial Intelligence and Deep Learning in Radiology

3a. AI CAD (Computer-Aided Detection/Diagnosis)

• Lung nodule detection on CT: FDA-cleared systems (e.g., Veye Lung Nodules, Sievert AI) match or exceed radiologist performance
• Mammography: AI triage tools reduce false positive recall rates; now used as independent "second reader" in several European screening programs
• Chest X-ray: Deep learning identifies pneumothorax, cardiomegaly, effusion, consolidation with AUC 0.97+
• Retinal fundus photography: Detection of diabetic retinopathy, glaucoma, AMD

3b. Stroke Imaging AI [PMID: 40197098 - Systematic Review, Radiology 2025]

• Automated ASPECTS scoring from non-contrast CT
• AI perfusion analysis (CT/MRI) - automated core infarct / penumbra mismatch
• LVO (large vessel occlusion) detection on CT angiography - reduces door-to-puncture time
• AI-driven thrombectomy candidacy decision support

3c. Radiology Foundation Models / Large Language Models

• GPT-4 Vision, Med-PaLM 2, and domain-specific models (RadFM, CheXagent) now handle multi-image radiology QA
• Automated structured report generation from imaging data
• Multimodal AI - integrating imaging + EHR + genomics - scoping review, Med Image Anal 2025 [PMID: 40482561]

3d. Radiogenomics

• Linking imaging features to genomic/molecular subtypes (e.g., EGFR mutation prediction from CT texture in NSCLC)
• Prostate cancer: Radiogenomics + AI integrating PI-RADS with genomic biomarkers [PMID: 41374949]
• MSK oncology: Integrating radiomics + genomics for sarcoma characterization [PMID: 40506947]

4. Radiomics and Texture Analysis

• Lung cancer: Predicting immunotherapy response from CT texture [PMID: 40755255 - Meta-analysis 2025]
• Prostate MRI: Quantitative PI-RADS augmentation; ADC histogram analysis [PMID: 39356481]
• Glioma grading, IDH mutation status prediction from MRI
• Hepatocellular carcinoma: Predicting microvascular invasion pre-operatively
• Breast cancer: Predicting pathological complete response to neoadjuvant chemotherapy

5. Theranostics in Nuclear Medicine [PMID: 41006727]

PSMA Theranostics (Prostate Cancer - Most Clinically Impactful)

• Diagnosis: ⁶⁸Ga-PSMA-11 PET/CT - superior sensitivity vs. conventional imaging for biochemical recurrence (detects disease at PSA < 0.5 ng/mL)
• Therapy: [¹⁷⁷Lu]Lu-PSMA-617 (Lutetium-177 PSMA) - VISION trial showed significant improvement in OS in mCRPC
• Next generation: [²²⁵Ac]Ac-PSMA targeted alpha therapy for PSMA-expressing mCRPC [PMID: 40872606]
• PSMA-RADS structured reporting system now standardized [PMID: 39702798]

SSTR (Somatostatin Receptor) Theranostics

• ⁶⁸Ga-DOTATATE PET/CT: Standard for neuroendocrine tumors (NETs) - replaces OctreoScan
• [¹⁷⁷Lu]Lu-DOTATATE (Lutathera): FDA-approved for SSTR-positive gastroenteropancreatic NETs
• Meningiomas: EANM/EANO joint guidelines (2024) for SSTR-based theranostics [PMID: 38898354]

Emerging Targets

• FAPI (Fibroblast Activation Protein Inhibitor): ⁶⁸Ga-FAPI PET - pan-tumor imaging, high tumor-to-background ratio; potential for FAPI-targeted therapy
• HER2, CAIX, FAP targeted theranostics in trials

6. Advanced MRI Techniques

Quantitative MRI

• T1 mapping / T1rho: Liver fibrosis, myocardial fibrosis without contrast
• T2 mapping: Cartilage integrity, myocardial inflammation
• T2 mapping:* Iron overload quantification (liver, heart, brain)
• Quantitative MRI breast [PMID: 41161796]: IVIM (intravoxel incoherent motion), MR spectroscopy, DCE parametric maps for lesion characterization beyond standard DCE-MRI

Diffusion Imaging Advances

• DWI/ADC: Standard for hepatic lesions, prostate (PI-RADS), rectal cancer, lymphoma
• DTI (Diffusion Tensor Imaging): White matter tractography; evolving role in surgical planning, TBI evaluation
• IVIM modeling: Separates perfusion from diffusion components without contrast
• DKI (Diffusion Kurtosis Imaging): Captures non-Gaussian water diffusion; superior to ADC for tumor grading
• VERDICT (Vascular, Extracellular, Restricted Diffusion for Cytometry in Tumors): Prostate cancer cell size estimation

Functional MRI (fMRI)

• Task-based fMRI: Pre-surgical mapping of eloquent cortex (motor, speech, visual)
• Resting-state fMRI: Functional connectivity; default mode network analysis in psychiatric disorders
• Ultra-high field 7T MRI: Submillimeter cortical layer imaging; hippocampal subfield mapping in epilepsy

Advanced MS Imaging [PMID: 40424444]

• Myelin water fraction (MWF) imaging
• Central vein sign on susceptibility-weighted imaging (SWI) - differentiates MS from MS-mimics
• Paramagnetic rim lesions (PRL): Iron-rimmed lesions on QSM (quantitative susceptibility mapping) - marker of chronic active MS lesions
• Ultra-high field 7T: Identifies cortical lesions missed at 1.5/3T

7. Multiparametric Ultrasound (mpUS)

Elastography

• Strain elastography: Operator-dependent; qualitative/semi-quantitative; color maps
• Shear wave elastography (SWE): Quantitative; liver fibrosis staging (replacing liver biopsy in many centers); thyroid nodule characterization; breast lesion assessment
• Point SWE vs. 2D SWE - 2D gives spatial map, less operator-dependent

CEUS (Contrast-Enhanced Ultrasound)

• Agent: SonoVue (sulfur hexafluoride microbubbles) - purely intravascular, no renal clearance
• LI-RADS v2023: CEUS criteria for HCC characterization - arterial phase hyperenhancement (APHE) + washout
• Splenic CEUS for accessory spleen, lymphoma, splenic infarct [PMID: 39417855]
• Scrotal CEUS for testicular torsion vs. tumor [PMID: 40249502]
• Bladder CEUS for bladder lesion characterization [PMID: 39325210]
• Bowel ultrasound + CEUS: Crohn's disease activity assessment [PMID: 41635930, 2026]
• Brain ultrasound advances: Transcranial US, intraoperative US with SonoVue [PMID: 39305556]

8. Interventional Radiology Advances

Interventional Oncology

• TACE (Trans-arterial chemoembolization): Drug-eluting beads (DEB-TACE) now standard; combined with checkpoint inhibitors (atezolizumab + bevacizumab) for HCC [PMID: 40264767]
• TARE/SIRT (radioembolization): ⁹⁰Y microspheres - radiation segmentectomy concept - ablative doses to one or two segments achieving results comparable to surgical resection in HCC [PMID: 40626876]
• Thermal ablation: Microwave ablation (MWA) now preferred over RFA for liver tumors >3 cm - faster, less heat-sink effect, no grounding pad burns
• Irreversible electroporation (IRE/NanoKnife): Non-thermal; preserves vessels and bile ducts; for tumors near critical structures (porta hepatis, pancreatic head)
• Cryoablation: Renaissance in renal, lung, and bone metastases; visually monitored ice ball; reduced post-ablation syndrome
• Interventional neuro-oncology [PMID: 40380871]: Laser interstitial thermal therapy (LITT), MRI-guided focused ultrasound, convection-enhanced delivery

Portal Hypertension

• TIPS (Transjugular Intrahepatic Portosystemic Shunt): PTFE-covered stents (Viatorr) now standard; early TIPS (within 72h) in high-risk variceal bleeders (Child B active bleeding, Child C<14) - HINT trial data

Stroke Intervention

• Mechanical thrombectomy with next-generation stent retrievers + aspiration (SAVE technique); extended time window (up to 24h with perfusion imaging selection)

9. Portable and Point-of-Care Imaging

• Portable CT [PMID: 40711856]: Bedside CT (NeuroLogica OmniTom, Samsung) for ICU/ER patients; neurocritical care monitoring; intracranial hemorrhage surveillance
• Point-of-care ultrasound (POCUS): FAST exam, lung ultrasound (B-lines for pulmonary edema, A-lines for pneumothorax), cardiac POCUS - now part of emergency medicine and critical care core competencies
• Handheld ultrasound devices (Butterfly iQ+, Vscan Air): AI-guided automated cardiac views; remote telemedicine deployment

10. Structured Reporting and RADS Systems (Exam Favourite)

11. Adrenal Imaging Advances [PMID: 41265468 - Lancet Diabetes & Endocrinol 2026]

• CT washout protocol: 15-min delayed phase - absolute washout >60% = adenoma; relative washout >40% = adenoma
• DECT: Material decomposition distinguishing lipid-rich vs. lipid-poor adenoma from metastasis without delayed phase (sensitivity 96%)
• ¹⁸F-FDG PET/CT: SUV > 1.8x liver suggests malignancy
• Functional adrenal imaging: ¹²³I-mIBG for pheochromocytoma; ⁶⁸Ga-DOTATATE for adrenal paraganglioma
• Radiomics-based adrenal characterization is the current frontier

12. Lung Cancer Screening (LDCT)

• USPSTF 2021 criteria: 50-80 years, 20 pack-year history, current smoker or quit within 15 years
• Lung-RADS v2022: Category 4X added (with additional features increasing suspicion)
• AI-assisted nodule detection reduces false negatives in screening programs
• Volume doubling time (VDT) preferred over diameter for follow-up
• Subsolid nodules (GGO, part-solid): separate management algorithm; part-solid nodules with >6mm solid component highest malignancy risk

Quick Revision: Key 2024-2026 "New" Facts for Vivas

• AI in stroke imaging: [Radiology 2025, PMID: 40197098]
• Photon-counting CT clinical results update: [Eur J Radiol 2025, PMID: 40516505]
• PCD-CT technology & dose reduction: [Br J Radiol 2025, PMID: 40424349]
• Theranostics in nuclear medicine: [Med Oncol 2025, PMID: 41006727]
• PSMA-RADS: [Abdom Radiol 2025, PMID: 39702798]
• Adrenal tumor imaging (Lancet D&E 2026): [PMID: 41265468]
• Advanced MRI in MS: [J Magn Reson Imaging 2025, PMID: 40424444]
• Multiparametric US intestinal: [Expert Rev Gastroenterol 2026, PMID: 41635930]
• Cardiothoracic CT future applications: [Radiology 2025, PMID: 40492912]
• Portable CT clinical applications: [Br J Radiol 2025, PMID: 40711856]