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Case 1.10
Published in Monica Fawzy, Plastic Surgery Vivas for the FRCS(Plast), 2023
Tell me – How does an MRI work?Magnetic resonance imaging employs powerful magnets to produce a strong magnetic field and force protons in the body to align with that field.Sensors detect the energy released by the protons after they are temporarily stimulated by a radiofrequency current that is pulsed through the patient.Intravenous contrast agents, such as gadolinium increase the speed at which protons realign with the magnetic field, with a brighter image produced by faster proton realignment.
Subthalamic nucleus stimulation in patients with intractable epilepsy: the Cleveland experience
Published in Hans O Lüders, Deep Brain Stimulation and Epilepsy, 2020
Silvia Neme, Erwin B Montgomery, Ali Rezai, Kathy Wilson, Hans O Lüders
A magnetic resonance imaging (MRI) scan of the brain was not used post-operatively because the safety of an MRI with implanted stimulators has not been established by the US Food and Drug Administration (FDA). Written informed consent was obtained from all patients.
Traumatic Brain Injury and Neurocognitive Disorders
Published in Gail S. Anderson, Biological Influences on Criminal Behavior, 2019
Magnetic resonance imaging (MRI) is an advanced medical diagnostic technique that uses a very powerful magnet, radiofrequency waves, and computer imaging techniques to provide an image of the body’s internal organs or structures. It can be used to image the brain, as well as any other structure. In the news, we frequently hear of sports figures awaiting results of the MRI of a recent injury to determine when and if they can return to their profession.
Intrarectal Foley catheter-assisted high-intensity focused ultrasound ablation for benign uterine diseases beyond the treatment region
Published in International Journal of Hyperthermia, 2023
Wei Liu, Tae-Hee Kim, Lihui Huang, Xing Chen, Chunping Feng, Ling Liu, Li Zhang, Wen Zhang, Kun Zhou, Xiuni Gan
All patients underwent pre- and post-treatment contrast-enhanced magnetic resonance imaging (MRI) within 2 days. Based on the images, three dimensions of the lesion were measured before (A1, B1, and C1) and after (A2, B2, and C2) the procedure. The non-enhancing area on contrast-enhanced T1-weighted images (T1WIs) after treatment reflected the non-perfused volume (NPV). The lesion volume and NPV were calculated using the following formula: V = 0.5233 × A × B × C. The NPV ratio (NPVR [%]), which was the percentage of hysteromyoma or adenomyotic volume being ablated and a marker of subsequent treatment success, was calculated using the following formula: (A2 × B2 × C2)/(A1 × B1 × C1) × 100. The number of lesions, lesion location, blood supply, T2-weighted image (T2WI) signal, and distance between the lesion and abdominal skin were recorded on preoperative MRI. The lesion’s blood supply was classified as rich, moderate, or poor based on the enhancement on T1WIs [11]. Myometrium enhancement was used as a reference standard; values higher than the reference value indicated rich supply, those similar to the reference value indicated moderate supply, and those lower than the reference value indicated poor supply (Figure 3). Signal intensity on T2WI was classified as low (equal to skeletal muscle signal), isointense (signal strength between that of skeletal muscle and myometrium), high (equal to myometrium signal), or mixed (existence of two or three signal types) [5].
Treatment of Sciatica and Lumbar Radiculopathy with an Intervertebral Foramen Opening Protocol: Pilot Study in a Hospital Emergency and In-patient Setting
Published in Physiotherapy Theory and Practice, 2023
Michael Shacklock, Marinko Rade, Siniša Poznic, Anita Marčinko, Michael Fredericson, Heikki Kröger, Markku Kankaanpää, Olavi Airaksinen
To ensure that pathologies did not have sufficient time to change, magnetic resonance imaging (MRI) was completed within 3 days of admission. This formed part of the cluster of tests for diagnosis (i.e. electrophysiological impairment, positive SLR, and leg pain ratings). The radiologist used MRI to detect disc herniation and radiculopathy by applying the Michigan State University classification of disc herniation size and position (Mysliwiec, Cholewicki, Winkelpleck, and Eis, 2010). Disc herniations were classified with lines between facets, canals and foramen for: 1) size: small, moderate, and large; and 2) location: midline, parameter or lateral. Briefly, this classification was validated prospectively in 200 patients over 5 years. The results from a previous series of 100 patients who were investigated with MRI and underwent microdiscectomy for back pain and radiculopathy were used to classify disc herniation and evaluated for reliability, indications for surgery and health outcomes (Oswestry). Those variables were then tested prospectively for validity in the next series of 100 patients. Between the two series, disc herniation classification reliability was 98% and surgery rates and the postoperative outcomes were not statistically different (Mysliwiec, Cholewicki, Winkelpleck, and Eis, 2010). The nerve roots in all patients were tested electro-physiologically and classified as normal or with a deficit in the sensory or motor divisions. For inclusion and exclusion criteria (Table 1).
Management of breast cancer diagnosed during pregnancy: global perspectives
Published in Expert Review of Anticancer Therapy, 2022
Jyoti Bajpai, Rima Pathak, T.S. Shylasree, Hope S. Rugo
Delayed diagnosis is common and to reduce such delays, clinical and self-breast examination should be a part of antepartum care especially in LMIC as this simple approach has shown a significant reduction in breast cancer mortality in a large Indian study [13]. Furthermore, creating awareness among obstetric care takers that to investigate a breast lump during pregnancy, ultrasound carries no risk and bilateral two view mammogram carries a negligible risk of radiation exposure to fetus.The actual radiation dose of< 3 mGy with a corresponding dose to the uterus and the fetus is <0.03 μGy [4,10,11].The threshold for negative radiation effects on the fetus is ~100 mGy, and at doses between 50 and 100 mGy there is uncertain risk involved [10,14].Maternal and fetal radiation exposure and dose are influenced by gestational age, anatomic site, modality, and technique. The imaging investigations are recommended only in advanced stages (rather than all stages) wherein they influence the treatment decisions as in nonpregnant breast cancer patients. Magnetic resonance imaging (MRI) with gadolinium-based contrast agents during BCP is insufficiently explored and therefore, not recommended [15–19]. MRI without contrast can be considered for primary breast in imaging a staging workup. Chest x-ray, ultrasound of the abdomen and pelvis and a non-contrast skeletal MRI are recommended staging investigations [10,20]. Histopathology is the gold standard to confirm the diagnosis with documentation of receptor status as in nonpregnant BC for therapeutic and prognostic relevance.