Magnetic Resonance Imaging (MRI)
MRI creates images from the magnetic resonance created in hydrogen atoms when they are polarized and an electromagnetic pulse is used to knock them off axis. This section includes MR analysis software, MRI scanners, gadolinium contrast agents and related magnetic resonance imaging accessories.
Chest CT images in a 34-year-old man with fever for 4 days. Positive result of reverse-transcription polymerase chain reaction assay for severe acute respiratory syndrome coronavirus 2 using a swab sample was obtained on February 8, 2020. Dates of examination are shown on images. A, Chest CT scan with magnification of lesions in coronal and sagittal planes shows a nodule with reversed halo sign in left lower lobe (box) at the early stage of the pneumonia. B, Chest CT scans in different axial planes and coronal reconstruction show bilateral multifocal ground-glass opacities. The nodular opacity resolved.
1H-MR spectra of 3 consecutive patients with COVID-19. Upper row: Axial FLAIR images at the corona radiata level show representative MRS voxels (black squares) from sampled periventricular regions. Lower row: Corresponding spectrum (black) and LCModel fit (red) from each patient acquired at TE = 30 ms (upper row) and TE = 288 ms (lower row). A, A patient with COVID-19-associated multifocal necrotizing leukoencephalopathy shows diffuse patchy WM lesions with markedly increased Cho and decreased NAA, as well as elevated Lac. B, A patient with COVID-19 after recent PEA cardiac arrest with subtle FLAIR hyperintense white matter changes also shows elevated Cho/Cr and decreased NAA/Cr ratios. However, these derangements are less severe than in the patient in A. There is no clear elevation of Lac. C, A patient with COVID-19 without encephalopathy or recent severe hypoxia has normal Cho/Cr, with mildly decreased NAA/Cr and no lactate elevation. Cho, Choline; NAA, N-Acetyl-Aspartate; mI, Myo-Inositol; Lac, Lactate; Glx, Glutamate + Glutamine. Image courtesy of AJNR
Chest X-ray from a patient included in the study. Posteroanterior view, of a 79-year-old man with history of a previous pacemaker, with abandoned right atrial and right ventricular pacing leads on the right side at time of new cardiac resynchronization therapy defibrillator implant on the left side. Arrows indicate a nodular opacity in the right midlung concerning for mass. Find more images of patients in this study in Radiology: Cardiothoracic Imaging.
This illustration show the complexity of the data obtained from one single patient with moderate/severe traumatic brain injury. Different imaging approaches and techniques have their own unique sensitivity in assessing different aspects of neuroanatomy and neuropathology. What can be seen on images also changes with time since injury. Data from comprehensive clinical and functional assessments using a range of other tools is also important for evaluating patient outcome. Through data harmonization and large-scale analyses of data combined across multiple research sites, the ENIGMA Brain Injury will develop and test methods and procedures for making sense of the complexity in this data. Images courtesy of Olsen et al., Brain Imaging and Behavior, 2020
(A) The fMRI hyperscanning environment. The clinician (1) and patient (2) were positioned in two different 3T MRI scanners. An audio-video link enabled online communication between the two scanners (3), and video images were used to extract frame-by-frame facial expression metrics. During simultaneous acquisition of blood oxygen level–dependent (BOLD)–fMRI data, the clinician used a button box (4) to apply electroacupuncture (EA) treatment (real/sham, double-blind) to the patient (5) to alleviate evoked pressure pain to the leg (6; Hokanson cuff inflation). Pain and affect related to the treatment were rated after each trial. (B) Study overview. After an initial behavioral visit, each individual participated in a Clinical-Interaction (hyperscan preceded by a clinical intake) and No-Interaction condition (hyperscan without a preceding intake), in a counterbalanced order, with two different partners. (C) Experimental protocol. Each hyperscan was composed of 12 repeated trials (four verum EA, four sham EA, and four no treatment) in a pseudo-randomized order. After a resting period (far left), both participants were shown a visual cue to indicate whether the next pain stimulus would be treated (green frame) or not treated (red frame) by the clinician. These cues prompted clinicians prepare to either apply or not apply treatment while evoking corresponding anticipation for the patient. Following the anticipation cue, moderately painful pressure pain was applied to the patient’s left leg, while the clinician applied or did not apply treatment, respectively. After another resting period, participants rated pain (patients), vicarious pain (clinicians), and affect (both) using a visual analog scale (VAS).
Lesion was originally reported as indeterminate enhancing mass, and outside report recommended biopsy. Classic features of benign hemangioma are shown. Error was attributed to faulty reasoning. A, Axial MR image obtained 5 minutes after contrast agent administration shows peripheral nodular discontinuous enhancement. B, Axial MR image obtained 10 minutes after contrast agent administration shows centripetal progression of enhancement (arrow). C, Axial fast imaging employing steady-state acquisition (FIESTA) MR image shows lesion is homogeneously hyperintense compared with liver parenchyma. Image courtesy of American Roentgen Ray Society (ARRS), American Journal of Roentgenology (AJR)
56-Year-Old Woman With Benign Hemangioma: Lesion was originally reported as indeterminate enhancing mass, and outside report recommended biopsy. Classic features of benign hemangioma are shown. Error was attributed to faulty reasoning. A, Axial MR image obtained 5 minutes after contrast agent administration shows peripheral nodular discontinuous enhancement. B, Axial MR image obtained 10 minutes after contrast agent administration shows centripetal progression of enhancement (arrow). C, Axial fast imaging employing steady-state acquisition (FIESTA) MR image shows lesion is homogeneously hyperintense compared with liver parenchyma.