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Posts Tagged ‘Magnetic Resonance Imaging’

The effects of delineation of adrenal lesions with 3D GRE and MP GRE in phase and out phase MRI techniques are corresponding to that gained with the reference standard 2D GRE method. Varied thresholds must be picked for diverse assessment techniques.

 

The medical research study was conducted by Miguel Ramalho, Rafael O. P. de Campos, Vasco Heredia, Brian M. Dale, Penampai Tannaphai, Rafael M. Azevedo and Richard C. Semelka from Department of Radiology, University of North Carolina at Chapel Hill, NC; Siemens Healthcare, Cary, NC.

The research objective was to utilize previously depicted quantitative research techniques to equate the performance of three dimensional gradient recalled echo, and  magnetization prepared gradient recalled echo  (MP-GRE) in phase and out of phase order with standard two dimensional gradient recalled echo, in delineating adrenal lesions.

The research model had about 44 successively enrolled patients (men and women) with 50 adrenal lesions that passed through standard abdominal magnetic resonance imaging, which encompassed in phase and out of phase two dimensional GRE, three dimensional GRE, MP-GRE etc.

Independent sample student t test was utilized for to compute and equate subsequent, for all three methods: adrenal signal intensity index and adrenal-to-liver, adrenal-to-muscle, and adrenal-to-spleen signal intensity ratios. The region under receiver operating characteristic (ROC) curve for each assessment method was established, and equations of independent ROC curves were executed for all the sequences.

About the results, signal intensity ratios of adenomas and nonadenomas, and mean adrenal signal intensity index varied considerably for all the sequences. For MP-GRE and 3D GRE, modified adrenal-to-spleen ratio and adrenal signal intensity index had larger area under the safety response curve; the deviation was not statistically significant; varied thresholds for all the methods were suggested for to discern nonadenoma from adenoma.

Conclusion: the outcomes of characterization of adrenal lesions with 3D GRE and MP GRE in phase and out phase MRI techniques are comparable to that acquired with the reference standard 2D GRE method. Varied thresholds must be picked in relation to in phase and out of phase methods utilized, and for diverse assessment techniques.

Multiparametric MRI protocol that encompasses diffusion weighted imaging facilitates for detection of local recurrence of tumor after high dose rate brachytherapy.

 

 

The medical research was conducted by Tsutomu Tamada, Teruki Sone, Yoshimasa Jo, Junichi Hiratsuka, Atsushi Higaki, Hiroki Higashi and Katsuyoshi Ito from Department of Radiology, Department of Urology, Department of Radiation Oncology (Kawasaki Medical School, Kurashiki City, Okayama, Japan).

The medical research objective was to retroactively assess the significance of prostate MRI for to discover locally recurrent prostate cancer, after high dose rate brachytherapy/internal radiotherapy.

About 16 subjects that had biochemical failure after high dose rate brachytherapy were made to pass through prostate MRI, inclusive of T2 weighted, dynamic contrast enhanced and diffusion weighted imaging, through 1.5T MRI system prior sample biopsy. Two radiologists, in agreement evaluated the existence of tumor on each arrangement -  from eight prostate regions, on grounds of biopsy/examination of tissue – two were from transition and other six were from peripheral zones.

About the results, tissue examination/biopsy disclosed locally recurrent prostate cancer in about 22 cases, of 128 regions; for T2 weighted imaging, the precision, specificity and sensitivity of each method in recognition of recurrent tumor was: 87%, 99% and 27%, respectively. The same for dynamic contrast enhanced MRI was: 90%, 98%, and 50%; for diffusion weighted imaging, it was – 91%, 95% and 68%, in the order.

The sensitivity of T2 weighted imaging in recognition of recurrent tumor was considerably lower than that of diffusion weighted imaging; except for inconsiderably reduced specificity, multiparametric MRI attained highest sensitivity.

Conclusion: multiparametric MRI procedure which comprises diffusion weighted imaging facilitates for a sensitive method, for to discover local recurrence of tumor after high dose rate brachytherapy.

The CNR and contrast enhancement ratio for hepatocellular carcinoma were not mutually related with histologic grades; contrast enhancement ratio was significantly lower in keratin 19–positive groups.

 

 

The medical research was conducted by Jin-Young Choi, Myeong-Jin Kim, Young Nyun Park, Jeong Min Lee, Sun Kook Yoo, Sun Young Rha and Jae Yeon Seok from Department of Radiology, Research Institute of Radiological Science, Yonsei University Health System; Department of Pathology, Department of Medical Engineering, Department of Internal Medicine, Yonsei Cancer Center, Cancer Metastasis Research Center (Yonsei University College of Medicine); Department of Radiology, Institute of Radiation Medicine, Seoul National University Hospital, Seoul; Department of Pathology, Ajou University College of Medicine, Suwon, Republic of Korea.

The medical research objective was to evaluate if gadoxetate disodium intensified hepatobiliary phase magnetic resonance imaging could identify out the histological factors, of hepatocellular carcinoma/liver cancer in patients.

About 51 patients were retroactively assessed, of 53 hepatocellular carcinoma cases histopathologically affirmed by surgery; all the subjects were passed through gadoxetate disodium intensified magnetic resonance imaging, prior surgical removal/resection.

Kruskal wallis test was utilized for to equate deviations in contrast enhancement ratio of the lesions, with deviations in contrast-to-noise-ratio (CNR) among histologic grades of hepatocellular carcinoma. Spearman’s non-parametric method was put in use to establish relationship between cell density ratio, contrast enhancement, contrast to noise ratio, and incontrovertibility for anti-hepatocyte antibody, keratin 19, and keratin 7.

About the results, of 53 cases of hepatocellular carcinoma, 50 demonstrated low signal intensity on hepatobiliary phase images, pertain to liver and biliary ducts, but 3 showed hyperintensity on the same in contrast with neighboring hepatic parenchyma/liver tissue. Even though well discerned HCCs inclined to demonstrate higher contrast enhancement, no statistical significance could be established amongst histological grade and contrast enhancement ratio of the tumors; there was even no considerable deviation amongst histologic grade and contrast-to-noise-ratio (CNR); the contrast enhancement ratios (tumors) were considerably higher in keratin 19 negative group, than in keratin 19 positive group. There was no significant relation between subsequent: cell density ratio, contrast enhancement ratio, and positivity for anti-hepatocyte antibody and keratin 7.

Conclusion: for hepatocellular carcinoma – the CNR and contrast enhancement ratio were not mutually related with histologic grades; contrast enhancement ratio was substantially lower in keratin 19–positive HCCs.

MRI scan is practicable for differentiation of necrotizing infectious fasciitis from nonnecrotizing infectious fasciitis.

 

The medical research study was conducted by Yeo Ju Kim, MD, Kyoung-Tae Kim, MD, Ju Won Lee, MD, Youn Jeong Kim, MD, Sun-Won Park, MD, Myung Kwan Lim, MD and Chang Hae Suh, MD from Departments of Radiology (Inha University Hospital, Incheon and Seoul National University Boramae Medical Center, Seoul, South Korea)

The study is available in online journal of Radiological Society of North America, and the research objective was to evaluate effectiveness of MRI findings for discrimination of necrotizing infectious fasciitis (NIF) from nonnecrotizing infectious fasciitis (non-NIF).

Approved by IRB (Institutional Review Board), the study was conducted on about 35 patients, presented with 23 non-NIF and 7 NIF cases. Through T2-weighted MR imaging, subsequent findings were evaluated by, of: deep fascial hyperintensity, thickening of abnormal signal density/deep fascia, its pattern in muscle along with degree of deep fascia and compartment involvement. On contrast material enhanced T1 weighted MRI – enhancement patterns of abnormal deep fascia and muscle were evaluated by, along with for presence of subcutaneous abscess.

About the results, on fat-suppressed T2-weighted images – patients with necrotizing infectious fasciitis had greater frequency of thick abnormal signal intensity and low signal intensity in deep fascia, with involvement of more than two compartments in an extremity.

Conclusion: Magnetic Resonance Imaging is practicable for discrimination necrotizing infectious fasciitis from that of nonnecrotizing infectious fasciitis.

The deviations in scanning capacity – MRI/CT may transform clinical management aspects, of patients demonstrated with stroke symptoms.

 

The medical research was conducted by Max P. Rosen, MD, MPH and associates, of Department of Radiology, and the study results are available in the Journal of the American College of Radiology.

The research objective was to understand about some of deciding factors of prescribing for diagnostic imaging, one of big and emerging constituent of healthcare overhead costs.

Researchers examined the effects of differential capacity of the imaging progress of patients with acute non hemorrhagic stroke.

The medical research team utilized data of patients from year 2001-2005, at US medical school and two-campus Canadian medical school that were discharged with diagnoses of acute non hemorrhagic stroke.

Their medical billing data coupled with clinical information systems were analyzed for identification of imaging studies, coexisting medical conditions (comorbidities), and patient disposition for varied reasons.

About 2677 patients, from US and Canadian hospital were included for the study, with patients analogous in age and dispersion of comorbid conditions.

MRI scan rate at the US hospital (95.75 scans per 100 patients) was double than either of the Canadian medical schools (41.39 scans per 100 patients).

The length of hospital stay and death rate were considerably shorter and lower at US medical school, in comparison to the Canadian medical school.

Multivariate regression analysis showed that only patient age/site were important forecasters of MRI usage, controlling for patient gender, comorbidities, and application of anticoagulants for prevention, or to hold back blood clotting.

The scanning usage differed at medical schools with differential access to scanning technologies. Usage frequency of MRI scanning was less in hospitals with inadequate access to the imaging modality.

Conclusion: Health system factors and patients are vital when translating the mechanisms for this disparity, its significance, and the possible relationship of imaging usage with patient outcomes.

 

MRI scanning enhances health outcomes for Medicare beneficiaries with implanted pacemakers, when the pacemakers are utilized agreeing with FDA approved labeling for use in an MRI environment, adjudicates – Centers for Medicare & Medicaid Services (U.S. Department of Health & Human Services),

CMS suggested that the usage of MRI is sensible and essential under Social Security Act §1862.

 

The following information is available from news center of American College of Radiology.

It anticipated for the change of language in section 220.2.C.1 of the Medicare National Coverage Determinations Manual, to get rid of the reason for Medicare coverage of MRI in beneficiary with imbedded pacemakers, when it is used in accordance to FDA approved labeling for use in an MRI environment.

Other contraindications, for the procedure that may be present in any given beneficiary would persist, in patients with pacemakers.

American College of Radiology (ACR) and North American Society for Cardiovascular Imaging (NASCI) commented on it saying that their societies harmonize with it, if clinically suggested under the advocated course of action of the manufacturing business that MRI is done only by individuals, at site with know-how and hands-on expertise on radiology and cardiology practice. They even remarked on the monitoring and precautionary measure, authenticated in the operating instructions of FDA approved device, to be bound to.

They contradicted Coverage with Evidence Development (CED). It was remarked that patients with FDA approved devices should have similar admittance to medically essential MRIs, as patients with no implanted medical devices.

NASCI & ACR even requested for the contraindication in section 220.2.C.1 to be substituted with the accompanying statement:

“The MRI examination is not covered when the following patient-specific contraindications are present: It is not covered for patients with pacemakers that have not been approved by the FDA for use in the MRI environment.”

Courtesy:
1)    http://www.acr.org/PR/NASCI-ACR-Comments.aspx
2)    http://www.acr.org/HomePageCategories/News/ACRNewsCenter/CMS-Concludes-MRI-Improves-Health-Outcomes-for-Patients-With-Pacemakers.aspx

The federal agency in the Department of Health and Human Services (Food and Drug Administration, US) approved and regulated the imaging agent (Gadovist: Gadolinium based contrast agent, which is a silvery-white ductile ferromagnetic trivalent metallic element) for to be utilized in patients that go through Magnetic Resonance Imaging (MRI scans) of the central nervous system.

Contrast agents/media are generally utilized on diagnostic medical imaging for to draw attention to/highlight specific regions and parts of the body, for to make the care providers see it easily, to work on. These contrast agents have wide applications in MRI scans, CT scans, X-Ray examinations, to name a few.

FDA approved/regulated this health product (Gadovist – contrast agent) on March 14, 2011, where the contrast agent has been proved well for enhanced imaging of the central nervous system, for to recognize and visualize out lesions/wounds that disturb the cells, to detach the brain from the blood stream, leading to grave medical conditions. Gadovist MRI scans were found viable for to identify out and envisage blood circulation/supply of the central nervous system, as it has been found to have improved the revelation of lesions in the nervous system, when equated to Magnetic Resonance Imaging scans without the utilization of contrast agents/media.

This (Gadovist: gadolinium-based contrast agent) is the 6th contrast agent/GBCA that has been approved/regulated by US Food and Drug Administration, for to be utilized in MRI scanning of the central nervous system, as the usage has been advised/recommended for children (above 2 years old) and adults. Gadovist is more saturated (high concentration) in comparison to other Gadolinium based contrast agents, as is generally required to be administered half the volume, and about 657 patients were put through clinical trials to establish out the efficaciousness and safety of Gadovist for to be used in MRI scans.

Gadovist and all other Gadolinium based contrast agents (GBCAs) come boxed with caution about the danger associated with that of Nephrogenic Systemic Fibrosis (NSF), which is a grave, yet rare medical condition related with the utilization of GBCAs in patients with kidney disorders. Nephrogenic Systemic Fibrosis is characterized by induced pain and hardening of the skin, where it can even cause fibrosis of internal organs through development of excess fibrous connective tissues, and there is no treatment available, as yet, for NSF.

Gadovist, which has been approved by US Food and Drug Administration – offers less risk of NSF, as unlike other GBCAs, it is not counseled in patients with advance/severe kidney failures or injuries, or other vital kidney dysfunctions.

People/patients that received Gadovist on study accounted for nausea and headache, as most ordinary undesirable reaction with the administration of the agent, along with other associated adverse events (mild-severe) like that of hypersensitivity reactions – respiratory, cardiovascular, skin etc.

Medical Researchers at the University of California are up with the usage of an advance technology of MRI (Magnetic Resonance Imaging) for to analyze carefully the human brain, for generation of proton density images, as they say – this new tech-gadget has the capability for to produce out images more rapidly than expected before.

The new MRI technology guarantees for brain scan 30 times faster than other advance MRIs available in the market., as when the research team generated few images at the onset through it, things were very swift and instant for them, as they got to obtain images/results concurrently, like never before.

The upsurge in the technology (in alliance with University of Minnesota) is supported on with the mix of radio frequencies (multiple pulses) for to image varied parts of the brain, in a concurrent manner, where the signals are alienated by manifold receivers that gauge out the location and time, and produce out more rapid scan results.

The team was able to scan the brain instantly, facilitated on Echoplane imaging, with a fraction of seconds, before, but now with the rise in the new MRI technology, they are capable for to do the same in about 100-300 milliseconds. Researchers believe, with the increase in speed, the induced MRI would have far-reaching impact on all research studies pertain to human brain anatomy, for to map the communication network of the brain, as supported on the new MRI technology, they were quite able to decipher out the brain communication network far better and precisely, than otherwise.

After comprehending the generic nerve pathway of the brain through support from new technology MRI, the research team now hopes that they would be able to uncover hints to various disorders/syndromes, viz. Alzheimer’s disease, Autism (of abnormal absorption with the self) etc.

A study published by the Journal of the American College of Cardiology suggests that Brain Magnetic Resonance Imaging (MRI) along with Transfemoral Aortic-valve Implantation (TAVI) detects emboli, an abnormal particle, probably an air bubble or part of a clot circulating in the blood, that usually goes undetected.

For patients with high surgical risk, a TAVI device have to be approved by the FDA, but still, some surgeons are using this method instead of surgery, in low-risk patients.The CoreValve and Edwards Sapien TAVI devices are widely used in Europe.

The study was conducted by Dr Alexander Ghanem and colleagues of University of Bonn, Germany. They found that when compared to conventional MRI, the incidence of clinically silent cerebral embolic lesions on MRI images after TAVI was high, but the incidence of persistent neurological impairment was low.

30 patients undergoing TAVI approach for the implantation of a CoreValve aortic-valve prosthesis were evaluated by Ghanem and his colleagues for the study. Out of them, 22 were evaluated with cerebral diffusion-weighted-MRI scans thrice – before, directly after and three months after – evaluating with TAVI.

It was found that there were three patients with neurological impairment following the TAVI, and only one with a permanent neurological impairment. Around 75 lesions were found in 16 patients, where scans were taken immediately after TAVI. 59 out of the 75 lesions were in the supratentorial region of the brain, which contains cerebrum and rest were in the infratentorial region, the part of the brain containing cerebellum. In 16 patients, MRI taken after three months of TAVI showed an infarcted tissue in the area of a lesion that had appeared in the scan right after TAVI.

According to the study, emboli appears on scans of those patients who already had cerebral events and cerebrovascular disease, and the patients with the emboli had a tendency of having worse renal function.

Ghanem said,

The study raises awareness of potential cerebral embolism, which most often stays clinically silent. This end point is a sensitive surrogate parameter for future neuroprotective approaches.