Haha, even me 😂

Glad it was helpful!

Ah, I’m so glad it helped! Good luck with the clinical research post 🙂

That's great to hear! I never know if I'm actually making sense or not 😅 so it's very helpful to get comments like this. Thank you Hameed

Thank you! I'm glad it helped 😊

There's no getting away from the physics 😖 Thanks for watching!

I'm really happy it had started to make sense for you Ravi! Thank you for your kind words 😊

Absolutely 👍

Great! I'm glad it helped Jade 😊

Sounds very interesting Kaustabh. Hope the project is going well. I’m glad this video could be of some help. All the best from South Africa 🇿🇦

I always find myself coming back to this to remind myself 😅 glad it’s helpful Pallavi!

Hello from 🇿🇦 to 🇲🇾! I'm glad the videos are helping 😊

So glad you enjoyed it 😀. Takes quite a lot of preparation 😆

That's great to hear Shiyuan!

Acute Stroke: 1. Diffusion-weighted imaging (DWI): In the acute phase, DWI shows hyperintense (bright) signals, indicating restricted diffusion of water molecules in the affected brain tissue. This is a sensitive marker for early stroke detection. 2. Apparent diffusion coefficient (ADC) map: Corresponding to the DWI, the ADC map shows hypointense (dark) signals in the affected area, indicating reduced water diffusion. 3. T2-weighted imaging (T2WI) and fluid-attenuated inversion recovery (FLAIR): These sequences may show hyperintense signals due to edema and tissue swelling in the affected region. Chronic Stroke: 1. T1-weighted imaging (T1WI): Chronic strokes typically appear as hypointense (dark) areas on T1WI, indicating tissue loss or cavitation in the affected region. 2. T2-weighted imaging (T2WI) and fluid-attenuated inversion recovery (FLAIR): These sequences may show hyperintense signals due to gliosis (reactive glial cell response) and hemosiderin deposition in the affected area. 3. T1-weighted post-contrast imaging: In some cases, chronic strokes may show enhancement or hyperintense signals on post-contrast images, indicating the presence of gliotic tissue or neovascularization. It's important to note that the appearance of stroke lesions on MRI can vary depending on the time elapsed since the onset of the stroke and individual patient factors. These MRI findings are typically assessed by radiologists or neurologists who have expertise in interpreting brain imaging studies.

Thank you!

Thank you Mihai. You're right. I definitely could have included that. Didn't want to confuse the core message. For interest briefly, the b value represents the magnitude and timing of the diffusion gradient we apply. As you've said it is prechosen by the clinician. This choice controls for the degree of observed diffusion. Similar to how TE controls T2 weighting. In my experience the reason certain doctors want different values is based on preference or experience with looking for specific pathology. There may be more nuanced reasons that I have yet to learn. Thank you for watching and taking the time to leave a comment ☺️

Thank you Masnla. I'm so glad it was helpful!

It's a pleasure. Any topics in particular you want me to cover?

Thank you 🙏🏻

Thank you Parastoo. That's very kind of you to say 😊

So glad to hear it. Thank you!

Pleasure Rodrigo 👍🏼 glad it was helpful!

Thank you Ina 😊

Thank you Alex 👍🏼

Yay! I'm glad!

Yay! Glad it helped Olga 🙂

Thank you Pallavi ☺️

Khush Raho Sarvejana. Thank you for watching and taking the time to comment. Many more MRI videos planned. Hopefully more to come in the next few weeks!

@@radiologytutorials I thank from bottom of my heart . Sparing your precious time and energy in Imparting knowledge to others is highest point of personal culture. Gurudevo Maheshwara (Teacher is equivalent to God for us ) 🙏

Thank you Andrés! Glad it helped 🙂

Thank you Matt. That really means a lot 😊

The b value in diffusion-weighted imaging (DWI) refers to the strength or level of diffusion sensitization applied during the image acquisition. It is a parameter that determines the extent to which the diffusion of water molecules is restricted or attenuated. In DWI, water molecules in biological tissues undergo random thermal motion known as Brownian motion. The diffusion of water molecules can be quantified by applying magnetic gradients during the imaging process. The b value represents the strength and duration of these gradients. A high b value corresponds to stronger diffusion sensitization, resulting in more signal attenuation from the diffusion of water molecules. This is useful for highlighting regions with restricted diffusion, such as areas affected by acute stroke or other pathologies. Conversely, a low b value corresponds to weaker diffusion sensitization, allowing a greater contribution from other tissue properties, such as blood flow or perfusion. This can help in assessing different tissue characteristics and distinguishing between various types of pathology. The choice of b value depends on the clinical application and the specific information required. In acute stroke imaging, higher b values (e.g., b = 1000-2000 s/mm²) are commonly used to enhance the visibility of restricted diffusion in the ischemic region. Lower b values (e.g., b = 0-100 s/mm²) are often employed in perfusion-weighted imaging to evaluate tissue perfusion. It's worth noting that the relationship between b value and DWI signal intensity is complex and influenced by various factors, including tissue microstructure and diffusion time. Advanced diffusion models, such as diffusion tensor imaging (DTI), can provide additional information about tissue anisotropy and fiber directionality. Overall, the selection of an appropriate b value in DWI depends on the clinical question, the specific imaging protocol, and the desired balance between diffusion sensitivity and other tissue properties of interest. Radiologists and clinicians use their expertise to optimize the b value selection for different clinical scenarios.

Wow! Thank you 🙏🏻 really appreciate it!

Thanks Gregory!

Yay! Glad it helped Anita 🙂

Thank you Iris 😊

My pleasure 🙏🏻

Most welcome 😊

Yeah, unfortunately my earlier video had low audio

Noted

Thank you Marc! I also end up forgetting it 😖 at least the video is here for when we inevitably forget again. Appreciate the kind words 🙏🏻

Thank you so much!! Really appreciate your support 🤗