Tag: MRI

Categories : CancerTags :

MRI-guided Radiation Therapy Reduces Side Effects from Prostate Cancer Radiotherapy

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A technique that uses MRI as a guide can make radiotherapy safer for prostate cancer patients by better aiming beams at the prostate while sparing nearby tissue in the bladder, urethra, and rectum. That is the finding of a thorough analysis of all published clinical trials of the technique, called magnetic resonance–guided daily adaptive stereotactic body radiotherapy (MRg-A-SBRT). The analysis is published in CANCER.

By providing detailed images, MRg-A-SBRT can be used to adjust a patient’s radiation plan every day to account for anatomical changes and to monitor the position of the prostate in real time while the radiation beam is on to ensure that treatment is being directed accurately to the prostate. Although MRg-A-SBRT is becoming more popular and multiple clinical trials have tested it, it is unclear whether the technique, which requires more time and resources than standard procedures, has an impact on clinical outcomes and side effects compared with other ways of delivering radiation.

To investigate, Jonathan E. Leeman, MD, of the Dana-Farber Cancer Institute and Brigham and Women’s Hospital, and his colleagues combined data from 29 clinical trials testing MRg-A-SBRT versus conventional CT-guided treatment, with a total of 2457 patients.

MRg-A-SBRT was associated with significantly fewer urinary and bowel side effects in the short term following radiation. Specifically, there was a 44% reduction in urinary side effects and a 60% reduction in bowel side effects.

“The study is the first to directly evaluate the benefits of MR-guided adaptive prostate radiation in comparison to another more standard and conventional form of radiation, and it provides support for use of this treatment in the management of prostate cancer,” said Dr Leeman.

Dr Leeman noted that the study also raises further questions regarding this type of treatment. For example, will the short-term benefits lead to long-term benefits, which are more impactful for patients? Longer follow-up will help answer this question because MRg-A-SBRT is a relatively new treatment. Also, which aspect of the technology is responsible for the improved outcomes seen in clinical trials? “It could potentially be the capability for imaging-based monitoring during the treatment or it could be related to the adaptive planning component. Further studies will be needed to disentangle this,” said Dr Leeman.

An accompanying editorial discusses the analysis’ findings, weighs the potential benefits and shortcomings of adopting this treatment strategy for patients, and questions the value of broad adoption.

Source: Wiley

Categories : CancerTags :

Ultrasound Scans Proven Effective in Prostate Cancer Diagnosis

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Results from a clinical trial showed that ultrasound scans are effective in prostate cancer diagnosis, which would be a cheaper option than MRI for low- and middle income countries. The study is published in Lancet Oncology.

“MRI scans are one of the tests we use to diagnose prostate cancer,” said Professor Hashim Ahmed, lead author of the study and Chair of Urology at Imperial College London. “Although effective, these scans are expensive, take up to 40 minutes to perform and are not easily available to all. Also, there are some patients who are unable to have MRI scans such as those with hip replacements or claustrophobia fears.  As cancer waiting lists build as a result of the COVID pandemic, there is a real need to find more efficient and cheaper tests to diagnose prostate cancer.

“Our study is the first to show that a special type of ultrasound scan can be used as a potential test to detect clinically significant cases of prostate cancer.  They can detect most cases of prostate cancer with good accuracy, although MRI scans are slightly better.

“We believe that this test can be used in low and middle income settings where access to expensive MRI equipment is difficult and cases of prostate cancer are growing.”

Prostate cancer develops slowly and symptoms such as the blood in the urine do not appear until the disease has developed. It usually affects men over 50 and often men with a family history of the disease. Black men are disproportionately impacted by the disease and prostate cancer deaths now exceed those from breast cancer.

One of the principal means of prostate cancer diagnosis is a multi-parametric MRI (mpMRI) scan. However, the 40-minute scan costs £350–450 (R7000-9000).

This new study tested multiparametric ultrasound (mpUSS) to image the prostate. Elastography examines tissue hardness, doppler and contrast-enhancement with microbubbles measures blood flow. As cancers are denser and have greater blood supply, they show up more clearly.
While mpUSS is more widely available than mpMRI, no large-scale studies have been done thus far to validate its effectiveness as a test to detect prostate cancer cases.

For the trial the team recruited 370 men at risk of prostate cancer. They were identified following initial tests such as a prostate-specific antigen (PSA) test and/or an abnormal digital rectal examination.

The men underwent both mpUSS and mpMRI scans at separate visits. This was then followed by biopsies for 257 patients who had a positive mpUSS or mpMRI test result. Cancer was detected in 133 men, with 83 men diagnosed with clinically significant cancer.

Individually, mpUSS detected 66 cases of clinically significant cancer compared to mpMRI which detected 77 cases.

Although mpUSS detected 4.3% fewer clinically-important prostate cancers compared to mpMRI, this method would lead to 11.1% more patients being biopsied as a result of false positives from the mpUSS.

The researchers believe that mpUSS could be an alternative to mpMRI as a first test for patients at risk of prostate cancer, particularly where mpMRI cannot be carried out. As both imaging tests missed clinically-important cancers detected by the other, using both would increase the detection of clinically-important prostate cancers overall.

Source: Imperial College London

Categories : NeurologyTags :

Significant White Matter Changes in Autism Revealed by MRI

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Significant alterations in the brain’s white matter in adolescents with autism spectrum disorder (ASD). Credit: RSNA and researcher, Clara Weber

Using specialised MRI, researchers found significant changes in the microstructure of the brain’s white matter, especially in the corpus callosum in adolescents and young adults with autism spectrum disorder (ASD) compared to controls. This research will be presented next week at the annual meeting of the Radiological Society of North America (RSNA).

“One in 68 children in the U.S. is affected by ASD, but high variety in symptom manifestation and severity make it hard to recognise the condition early and monitor treatment response,” explained Clara Weber, postgraduate research fellow at Yale University School of Medicine. “We aim to find neuroimaging biomarkers that can potentially facilitate diagnosis and therapy planning.”

Researchers reviewed diffusion tensor imaging (DTI) brain scans from a large dataset of patients between the age of six months and 50 years. DTI is an MRI technique that measures connectivity in the brain by detecting how water moves along its white matter tracts. Water molecules diffuse differently through the brain, depending on the integrity, architecture and presence of barriers in tissue.

“If you think of gray matter as the computer, white matter is like the cables,” Weber said. “DTI helps us assess how connected and intact those cables are.”

For the study, clinical and DTI data from 583 patients from four existing studies of distinct patient populations were analysed: infants (median age 7 months), toddlers (median age 32 months), adolescents, and young adults.

“One of the strengths of our study is that we looked at a wide range of age groups, not just school-aged children,” Weber said.

To assess the influences of age and ASD diagnosis on white matter microstructure, the research team created fractional anisotropy, mean diffusivity and radial diffusivity maps using data from the four studies.

Fractional anisotropy is the extent water diffusion is restricted to just one direction. A value of zero means that diffusion is unrestricted in all directions, while one means that diffusion is unidirectional. Mean diffusivity is the overall mobility of water molecules, indicating how densely cells are packed together. Radial diffusivity is the extent water diffuses perpendicular to a white matter tract.

“When white matter integrity is disrupted, we see more water diffusing perpendicularly, which translates to a higher radial diffusivity,” Weber said.

The key finding of the analysis was reduced fractional anisotropy within the anterior/middle tracts of the corpus callosum in adolescent and young adult ASD patients compared to individuals in the control group. The corpus callosum is a thick bundle of nerve fibers that connects and allows the two sides of the brain to communicate. Corresponding increases in ASD-related mean diffusivity and radial diffusivity were found in young adults.

“In adolescents, we saw a significant influence of autism,” Weber said. “In adults, the effect was even more pronounced. Our results support the idea of impaired brain connectivity in autism, especially in tracts that connect both hemispheres.”

Compared to controls, no reduction in fractional anisotropy was seen in the same tracts in toddlers and infants with ASD.

The researchers hope the findings can help improve early diagnosis of ASD and provide potential objective biomarkers to monitor treatment response.

“We need to find more objective biomarkers for the disorder that can be applied in clinical practice,” Weber said.

Source: EurekAlert!

Categories : CancerTags :

MRI Clear Cell Likelihood Score Matches Renal Carcinoma Growth

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According to a new study, the MRI-derived standardised non-invasive clear cell likelihood score (ccLS) is correlated with the growth rate of small renal masses (cT1a, <4 cm) and could help guide personalised management.

The study was published in the American Roentgen Ray Society’s American Journal of Roentgenology. Extracted from clinical reports, “the ccLS scores the likelihood that the small renal mass represents clear cell renal cell carcinoma, from 1 (very unlikely) to 5 (very likely),” explained corresponding author Ivan Pedrosa from the University of Texas Southwestern Medical Center at Dallas. “Small renal masses with lower ccLS may be considered for active surveillance, whereas small renal masses with higher ccLS may warrant earlier intervention.”

The team’s retrospective study included consecutive small renal masses assigned a ccLS on clinical MRI exams performed from June 2016 to November 2019. Tumour size measurements were obtained from available prior and follow-up cross-sectional imaging examinations, up to June 2020.

Among 389 small renal masses in 339 patients (198 men, 141 women; median age, 65 years) on active surveillance that were assigned a ccLS on clinical MRI examinations, those with ccLS4-5 grew significantly faster (9% diameter, 29% volume yearly) than those with ccLS1-2 (5% diameter, p<.001; 16% volume, p<.001) or ccLS3 (4% diameter, p<.001; 15% volume, p<.001).

With a lack of validated imaging markers to characterise biologic aggressiveness of small renal masses hindering medical decision making, “growth is associated with ccLS in small renal masses,” the authors reiterated, “with higher ccLS correlating with faster growth.”

Source: EurekAlert!

Categories : Cardiovascular DiseaseTags :

Earlier, Improved MRI Detects ‘Broken-heart’ Syndrome

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A new study from Karolinska Institutet in Sweden suggests that early magnetic resonance imaging (MRI) of the heart can greatly increase the rate of diagnosis of broken-heart syndrome, which can happen when there is no obvious cause in the coronary artery. 

Myocardial infarction is typically caused by a blockage of the coronary artery by a blood clot. However, in up to 10% of all myocardial infarctions, no obvious cause in the coronary artery is found, and so the working diagnosis MINOCA (myocardial infarction with non-obstructive coronary arteries) is given, which can subsequently lead to one of several diagnoses.

Most of these patients are women, many of whom are diagnosed with takotsubo cardiomyopathy (broken-heart syndrome), characterised by reduced heart function that is likely stress-related, presenting the same symptoms as a standard heart attack.

“Around 80 to 90% of broken-heart sufferers are women, and the disease is associated with mental stress,” said principal investigator Per Tornvall, senior physician and professor at the Department of Clinical Science and Education, Stockholm South General Hospital, Karolinska Institutet. “There also seems to be a link to hypersensitivity towards stress caused by low estrogen levels. Unfortunately, research on the investigation and treatment of myocardial infarction is often done on men, while female heart disease is less studied.”

In a prior study with 150 patients, cardiovascular magnetic resonance (CMR) is often done when examining patients with MINOCA. CMR conducted approximately 10 days after onset can result in a diagnosis in under half the patients, normally takotsubo or myocarditis (inflammation of the heart muscle), Now, the same researchers have tested a new, more sensitive CMR technique two to four days after onset on a comparable group of 148 patients. They found that 77% of the patients could be diagnosed: 35% of takotsubo and 17% of myocardial inflammation, compared with 19 and 7%, respectively, in the first study.

“We don’t know how much effect the improved CMR technique has, but the results suggest that with early examination more patients can get a correct diagnosis and therefore the right treatment,” says Professor Tornvall. “The next step is for us to develop the CMR examination with pharmacological stress of the heart. This will enable us to study the smallest of the blood vessels and hopefully find a cause for the 23% who received no diagnosis.”

Source: Medical Xpress

Journal information: Peder Sörensson et al. Early Comprehensive Cardiovascular Magnetic Resonance Imaging in Patients With Myocardial Infarction With Nonobstructive Coronary Arteries, JACC: Cardiovascular Imaging (2021). DOI: 10.1016/j.jcmg.2021.02.021