
Neuroimaging clinician-scientist | Professor @columbiaimaging #Neurorad
New York, NY
Joined December 2011
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Original Article: Mechanical Thrombectomy 24 to 72 Hours after Large-Vessel Ischemic Stroke (LATE-MT trial) nej.md/3VWTUpV
Editorial: Expanding the Evidence and Indications for Thrombectomy in Ischemic Stroke nej.md/4hWsxVs
#Neurology #Surgery
Sam.Payabvash retweeted
Replying to @_jasonwei
Great post…thanks for sharing your thoughts. If I may opine on this as a radiologist with some technical understanding of LLMs/VLMs: I agree radiologists will not be automated away anytime soon. Your elastic demand point is mostly right (some modalities impart ionizing radiation so there is a good reason to not scan as frequently as you want), and I’d add a more fundamental one.
The current transformer-based AI algorithms are extremely sample-inefficient compared to humans, especially when it comes to vision tasks (as opposed to text-based tasks). When I was a radiology resident, I read maybe 3000 CTs of the chest, abdomen and pelvis to reach expert/attending level. I can also make a rare-disease diagnosis after having seen 1 example study (or none; I can make a real-life diagnosis purely from reading and seeing an example case from a textbook). Currently, the best radiology VLM models, such as Nvidia’s NV-Reason-CT model, do not reliably call even some of the most common pathologies, despite having trained on >70,000 CTs that surely contain many examples of a common finding (macro-F1 of 0.614). I can think of several reasons for this: these models usually leverage weakly supervised learning such as CLIP, pairing radiology reports with the images, since wide-scale expert annotation is impractical for every study for every finding (Radiology’s Bitter Lesson, if you will; however, the signal that can scale is the noisy one). To scale, the model(s) will need to learn to associate image findings with words in the radiology reports. However, using radiology reports as ground truth can substantially limit learning. (1) As any radiologist will tell you, we don’t mention everything that we see. Otherwise, your radiology report would be like 30 pages long and not clinically useful. We mostly call the things that matter (for the most part). Sometimes, we don’t even call things that matter. Thus, some reports may mention “diverticulosis” when there is diverticulosis, while other reports don’t, even if there are findings of diverticulosis in the images. (2) Another limitation is that the actual real ground truth is never confirmed, which I suspect is a much bigger problem and harder to correct. When I was a radiology resident, I saved many cases in which my attendings and I made a certain call, and I was curious if those were correct. Right before I was about to graduate, I checked every case I had logged. Many calls were incorrect (and I trained at a major academic center in which subspecialized radiologists read their part of the body, so the attendings making those calls are above-average radiologists; real-world data is likely much worse). (1) and (2) make training very difficult when there is so much incorrectness, ambiguity and noise in the training data.
The above observations are pretty self-evident when you look at other vision tasks, such as self-driving, for which there is (1) ample data with predominantly correct actions (labels), and (2) known ground truths (the task of driving is, for the most part, unambiguous. You see a red light, you stop. You want to make a left turn? You signal and yield to passing cars before turning. Those are universally agreed-upon “correct” actions). To use Tesla FSD as an example: even with the best compute, engineers and data, it took over a decade to reach limited, geofenced driverless service. And this is despite the fact that driving has a much shorter tail than radiology does. Further, self-driving usually has one correct action at a time. In radiology, that’s not true. There are so many different radiological appearances of one disease, as well as the same appearances of different diseases. And various diseases can involve the same anatomical location (for example, look up adrenal collision tumor).
To “automate radiology” is also a huge simplification. The vast breadth of radiological studies is seldom mentioned. For a single modality of a body part, there are so many different variants. Say, for example, CT of the abdomen and pelvis: there are at least 10 different flavors of this. To name a few, there is the non-contrast CT, the portal venous phase CT (bread-and-butter workhorse), and then there are specialized versions such as the liver mass protocol, CT angiogram GI bleed protocol, pancreatic mass protocol CT, adrenal mass protocol CT, kidney mass protocol CT, and CT urogram, each of which contains 3-4 phases and is tailored to answer a specific question. All of this is just one modality for one section of the body. Now do ultrasound, X-rays, gamma studies, PET studies, and MRI. And then consider all the other body parts (brain, head and neck, chest, etc.).
I’ve only touched upon the surface of all the nuances, but I think the current capability gap and your demand argument point the same way: radiologists will be busy for a long time.
Sam.Payabvash retweeted
Despina Kontos, PhD (@DespinaKontos) on the potential for #AI to transform breast cancer screening.
#CIMBID #ArtificialIntelligence #DataScience #HealthcareInnovation #BreastCancerAwarenessMonth
Check #AJNR Editor’s choice of the month ‘’Diagnostic Utility of Arterial Spin-Labeling MRI in Straight to MRI Code Stroke Patients for Seizure Detection: A Comparison with FLAIR, DWI, and EEG’’
ASL MRI detects transient cerebral perfusion changes in acute seizures and may help localize the epileptogenic zone when conventional MRI findings are limited.
In this retrospective study, 61% of patients showed ASL hyperperfusion and 29% hypoperfusion, with frontal and occipital ASL abnormalities independently associated with EEG abnormalities. ASL had the highest sensitivity (95.4%) for detecting abnormalities corresponding to EEG, while DWI had the highest specificity.
ASL may be a valuable adjunct to FLAIR, DWI, and EEG for distinguishing seizures from stroke and improving diagnostic confidence.
ajnr.org/content/47/9/2394
#neuroradiology #neuroscience #radlife #medschool #medstudent #epilepsy #mri
Sam.Payabvash retweeted
Our virtual open house is in one week! We hope all #FutureRadRes will join us and meet some of our amazing residents, ask your questions, and learn what makes our program great!
Register here: app.smartsheet.com/b/form/bb…
Sam.Payabvash retweeted
Anterior Cerebral Artery Occlusion: An Exciting Target for EVT Not Fully Appreciated by the Major MeVO Trials?
In this #BloggingStroke post, Matthew Smith discusses #Stroke article by Zhang, Jing, and Abdalkader et al. @NguyenThanhMD ahajournals.org/do/10.1161/b…
"Quality of Evidence and Clinical Impact in Recent Neuroradiology Research: A Systematic Assessment of American Journal of Neuroradiology Articles"
doi.org/10.3174/ajnr.A9193
@SheriefGhozy; @ajayradiology; @AjayMalhotraRad; @YaleRadiology; @SamPayabvash; @dheemanf04; @dgandhimd; @theAJNR_EIC
“Commercial AI tools did not improve diagnostic accuracy and, for some findings, reduced it through increased false positives” #AI #radiology @AcadRadiol academicradiology.org/articl…
Check #AJNR Fellows’ Journal Choice of the month: ‘Predictive Factors for Traumatic Intraparenchymal Hemorrhage Expansion and Its Clinical Outcomes’
This retrospective study investigated predictors of intraparenchymal hemorrhage (IPH) enlargement following traumatic brain injury to identify patients who may benefit from routine follow-up CT. IPH enlargement occurred in 30% of cases and was independently associated with a larger initial hematoma and concomitant subarachnoid hemorrhage. Hematoma expansion was also associated with increased rates of intensive care admission, surgical intervention, and mortality. Conversely, small, isolated IPHs (≤5 mm) neither enlarged nor required intervention, suggesting that routine follow-up CT may be unnecessary in this low-risk group. These findings support a selective imaging strategy that could reduce radiation exposure and health care costs while improving hospital efficiency without compromising patient safety.
ajnr.org/content/47/8/2197
#neuroscience #neuroradiology #IPH #radiology #medschool #medstudent
Sam.Payabvash retweeted
A faculty member cut her research effort in half over three years. No one told her to. The comp plan did it for her. RVU-only compensation has destroyed more research capacity at academic medical centers than any funding cut.
Sam.Payabvash retweeted
Round 2 with @theASFNR State of Practice papers in @TheAJNR! Here is our latest one on the role of #ASL in #stroke, lead by @mona_gad_! @Hopkins_Rad @hopkinsneurorad @theAJNR_EIC @yedavaSNAPlab @dhairyalakhani @hamza_isleem @aakanksha_s_md @HanzhangLu
pubmed.ncbi.nlm.nih.gov/4246…
Sam.Payabvash retweeted
Ultra-high-resolution photon-counting CT angiography enables accurate, noninvasive detection of neurovascular ISR and may improve poststent surveillance. #stroke ahajrnls.org/4fn4GwF
Sam.Payabvash retweeted
The 2026 AHA/ASA AIS guideline update introduces key changes, including expanded guidance for MeVOs, updated IVT/EVT selection, & new pediatric stroke recommendations. This review summarizes the updates most relevant to radiology workflows.
By @pranj_rad
doi.org/10.3174/ajnr.A9455
Sam.Payabvash retweeted
For hospitalized patients with chronic subdural hematoma, early MMA embo leads to
Higher rates of discharge home
Lower rates of death
Lower rates of rescue surgery
Consider MMAE early!
Our new pub in Radiology:
pubs.rsna.org/doi/10.1148/ra…
@UM_NIS @UMDNeurosurgery @Dheeraj_NIS
Sam.Payabvash retweeted
A new @NIH grant to advance stroke research, led by Ajay Gupta, MD, MS, and colleagues at @columbiaimaging and @WeillCornell, will harness advanced imaging and #AI to look at hidden causes of cryptogenic, or unexplained, strokes.
columbiaradiology.org/news/n…
The time has come to vote for your favorite AJNR publications of the year!
View the nominees here: bit.ly/ajnrnominees
Vote here: bit.ly/ajnrvoting
Votes will be accepted until April 13th, 2026.
The time has come to vote for your favorite AJNR publications of the year!
View the nominees here: bit.ly/ajnrnominees
Vote here: bit.ly/ajnrvoting
Votes will be accepted until April 13th, 2026.
Sam.Payabvash retweeted
While Iranians danced in the streets, major Western outlets dressed up Ayatollah Khamenei as a statesman instead of what he was: the architect of decades of terror at home and abroad, writes Maya Sulkin. thefp.com/p/the-posthumous-m…






































