Cancer screening with full-body MRI scans and a seminar on the field of radiology | Rajpaul Attariwala, M.D., Ph.D. (#61 rebroadcast)
Jul 3, 2023
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Raj Attariwala, a dual board-certified radiologist and nuclear medicine physician, joins to reveal how his engineering background led to groundbreaking MRI technology for cancer detection. He discusses the unmatched resolution of full-body scans and the critical topics of sensitivity, specificity, and the risks of false positives in cancer screening. The conversation also covers the evolution of imaging technologies from X-rays to MRIs, emphasizing the innovations aimed at enhancing diagnostic accuracy while mitigating radiation exposure risks.
Mammography combined with ultrasound improves breast cancer detection in women with dense breast tissue.
CT scans are essential in evaluating trauma patients and guiding surgical interventions, despite radiation exposure concerns.
Ultrasound imaging provides real-time visualization of internal structures, making it valuable for diagnosing and monitoring various conditions.
MRI offers exceptional soft tissue contrast and non-invasive imaging capabilities, aiding in accurate assessments and treatment plans.
The tradeoff between sensitivity and specificity in mammography emphasizes the need for considering individual factors and multiple tests for accurate diagnosis.
Deep dives
Mammography and Ultrasound for Breast Cancer Screening
Mammography is an imaging technique that uses low-energy x-rays to visualize breast tissue. It is most effective in detecting breast cancer in women with predominantly fatty breast tissue. However, for women with dense breast tissue, mammography may not be sufficient, as the dense tissue can obscure potential abnormalities. In such cases, ultrasound imaging is often used in conjunction with mammography to provide a more comprehensive assessment. Ultrasound uses high-frequency sound waves to create images, allowing for the visualization of different tissue types and the detection of abnormalities. The combination of mammography and ultrasound improves sensitivity and accuracy in detecting breast cancer, especially in women with dense breast tissue.
CT Scan in Trauma Evaluation
CT scans play a crucial role in the evaluation of trauma patients, particularly in identifying and assessing internal injuries. CT scans provide detailed images of different anatomical structures, allowing for the detection of injuries such as fractures, bleeding, and organ damage. These scans are fast and provide valuable information that helps guide surgical interventions and determine the appropriate course of treatment. However, radiation exposure is a concern, especially for repeat CT scans. In time-sensitive cases where immediate surgical intervention is necessary, CT scans may be performed to obtain crucial information quickly and efficiently.
The Value of Ultrasound in Medical Imaging
Ultrasound imaging uses high-frequency sound waves to produce real-time images of internal structures. It provides a safe and non-invasive alternative to other imaging techniques that utilize ionizing radiation. Ultrasound is highly versatile and can be used to visualize various organs, assess blood flow, and guide procedures. Its effectiveness lies in its ability to detect anatomical and functional changes, making it an essential tool for diagnosing and monitoring conditions such as heart disease, organ abnormalities, and pregnancy. Skilled ultrasound technicians can interpret ultrasound images and provide valuable clinical insights.
MRI and its Role in Medical Imaging
Magnetic Resonance Imaging (MRI) is a powerful imaging technique that uses a combination of powerful magnets and radio waves to create detailed images of the body's internal structures. MRI provides exceptional soft tissue contrast and is particularly effective in visualizing the brain, spinal cord, joints, and soft tissues. It is non-invasive and does not involve the use of ionizing radiation. However, it can be time-consuming and less accessible due to the need for specialized equipment. MRI is a valuable tool in diagnosing and monitoring various conditions, helping healthcare professionals make accurate assessments and treatment plans.
Specificity and sensitivity in mammography
Mammography has a tradeoff between sensitivity and specificity. While specificity can be increased by selecting patients with fatty breasts, it can be reduced in patients with dense breast tissue, resulting in a higher rate of false positives. The importance of not relying solely on one test and considering individual factors for accurate diagnosis is emphasized.
Machine learning in mammography
Machine learning techniques are being explored and utilized in mammography to assist radiologists. Some companies are working on using machine learning to analyze mammogram data and act as a second reader for radiologists, improving sensitivities and specificities. However, achieving high accuracy levels comparable to human radiologists will require extensive data and further advancements in machine learning technology.
MRI and its potential for health assessment
MRI, also known as magnetic resonance imaging, is a powerful tool that provides detailed anatomical images. The combination of anatomical imaging with functional imaging, such as diffusion-weighted imaging (DWI), offers a comprehensive assessment of health. DWI can detect areas with restricted water diffusion, indicating potential abnormalities or tumor growth. By merging anatomic and functional data, MRI provides valuable insights into the state of various organs and can assist in disease detection and diagnosis.
Advancements in MRI technology
The development of customized hardware and software in MRI has revolutionized imaging capabilities. By optimizing parameters and sequences, it is possible to enhance the sensitivity and specificity of MRI across different body parts. Combining advanced hardware with functional imaging techniques like DWI allows for detailed health assessments and improved cancer detection. The customization of MRI technology offers significant potential for precision medicine and comprehensive health evaluations.
Advantages of MRI over mammography and CT scans for diagnostic imaging
MRI provides detailed imaging and has no radiation, making it an attractive alternative to mammography and CT scans. Some patients prefer MRI due to its minimal radiation exposure. MRI can detect abnormalities such as scar tissues that may not be visible on other imaging modalities.
The potential of MRI with DWI in cancer screening
MRI with diffusion-weighted imaging (DWI) has shown promise in cancer screening, particularly for prostate and breast cancer. DWI combined with other molecular tests has improved the accuracy of prostate cancer detection. For breast cancer, studies have shown that the sensitivity of MRI with DWI is comparable to contrast-enhanced breast MRI. However, standardization of MRI protocols and software is necessary for widespread use and better image interpretation.
In this episode, radiologist/engineer, Raj Attariwala, explains how he was able to apply his engineering background to create a unique MRI scanner that is capable of constructing whole-body images with a resolution that is unmatched in the industry. Peter and Raj discuss the implications of such a robust, radiation-free imaging tool on the early detection of cancer. They dive deep into cancer screening and define terms such as sensitivity and specificity that are necessary to really understand this complex space. They then describe the biggest risks involved in this type of screening (false positives) and how Raj’s unique technology and process might drive down this risk substantially. But before that, they discuss all the common imaging technology from X-ray, to CT scan, to PET scans, to ultrasound, to MRI, and more. They touch on the history of each, how they work, the usefulness and limitations of each of them, as well as the varying risks involved such as radiation exposure. If you are interested in cancer screening and/or you’ve ever wondered how any radiology tool works, this episode is for you.
We discuss:
Raj’s road from engineering to radiology [2:45];
How X-ray works, the risk of radiation exposure, and the varying amounts of radiation associated with the different imaging technologies [13:00];
Computed tomography scans (CT scans): The history of CT, how it works, and why we use contrast [22:45];
Ultrasound: Benefits and limitations, and a special use for the heart [36:00];
Detecting breast cancer with mammography: When is works, when you need more testing, and defining ‘sensitivity’ and ‘specificity’ [46:15];
Magnetic resonance imaging (MRI): How it works, defining terms, and looking at the most common types of MRI [59:00];
Brain aneurysms: Using MRI to find them and save lives [1:18:45];
Raj’s unique MRI technology [1:25:15];
The risk of false positives in cancer detection, and how Raj’s MRI can reduce the number of false positives (i.e., increase specificity) [1:38:45];
The unique software Raj created to pair with his MRI machine [1:46:15];
Comparing the radiation exposure of a whole-body PET-CT to Raj’s equipment (DWIBS-MRI) [1:48:45];
How diffusion-weighted magnetic resonance imaging (DW-MRI) has revolutionized cancer screening [1:50:15];
Why a DW-MRI is still not a perfect test [1:54:15];
The potential for advancing MRI technology: Where does Raj think it could improve in the next 5-10 years? [1:58:00];/li>
Are there any commercially available scanners that can match the resolution of Raj’s images? [2:01:00];
Machine learning: When and where might machine learning/AI impact the field of radiology? [2:03:45]; and
