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.
A new technique developed by researchers at UC Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The team created a probe that generates two magnetic resonance signals that suppress each other until they reach the target, at which point they both increase contrast between the tumor and surrounding tissue. Image courtesy of Xiandoing Xue, UC Davis
Experimental Protocol and Representative MRI of Brains at Various Key Points in That Protocol. (A) Experimental timeline. (B) Representative T2WI (using an 11.7T MRI) of the brain of a postnatal day (PND) 11 pup, 1 day after inducing left HII and prior to hNSC transplantation. Note the beginning of an increasingly intense “water signal” (white) on the left (“HII lesion”). (C) Representative T2WI (using an 11.7T MRI) 3 days post-HII, shortly after implantation of SPIO pre-labeled hNSCs into the contralateral cerebral ventricle (“Lateral Vent”). Note the “HII lesion” on the left becoming hyperintense (white) and the black signal void of the SPIO-labeled hNSCs in the lateral ventricle (black arrow). Red arrows denote the needle track. In contrast to what occurs in the intact brain (Figure S4), in a brain subjected to left HII, the implanted SPIO-labeled hNSCs (black signal void) (black arrow) migrate from the right (“R”) to the left (“L”) hemisphere to enter the lesion. (D and E) Shown here (using a 4.7T MRI) are SPIO-labeled hNSCs (black signal void) (black arrow) at 1 month post-implantation into the contralateral ventricle (D) and, in the same representative animal, at 3 months post-implantation (E)–stably integrated and surrounding a much-reduced residual lesion, with no interval enlargement of the graft or ventricles.
Axial (A) and coronal (B) CT of the abdomen and pelvis with IV contrast in a 57-year-old man with a high clinical suspicion for bowel ischemia. There was generalized small bowel distension and segmental thickening (arrows), with adjacent mesenteric congestion (thin arrow in B), and a small volume of ascites (* in B). Findings are nonspecific but suggestive of early ischemia or infection. Image courtesy of RSNA
Figure 4 for the study. Images of a 65-year-old man (patient 6). (a) Cardiac MRI perfusion shows perfusion deficit of anterior/anterolateral wall attributed to left anterior descending artery/left circumflex artery (*). (b) CT coronary angiography. (c) Coronary angiography, left anterior oblique projection with caudal angulation. (d) Three-dimensional image fusion helped refine diagnosis: perfusion deficits (*) were most likely caused by narrow first diagonal branch and its first, stented side branch (arrowhead). Retrospectively, denoted lesion could also be found at CT coronary angiography and coronary angiography (arrowheads in b and c, respectively). CT FFR = CT-derived fractional flow reserve, LGE = late gadolinium enhancement. Image courtesy of RSNA, Radiology.
A, Image from noncontrast head CT demonstrates symmetric hypoattenuation within the bilateral medial thalami (arrows). B, Axial CT venogram demonstrates patency of the cerebral venous vasculature, including the internal cerebral veins (arrows). C, Coronal reformat of aCT angiogram demonstrates normal appearance of the basilar artery and proximal posterior cerebral arteries. Image courtesy of the Radiological Society of North America (RSNA)