Magnetic Resonance Urography (MRU)

Magnetic resonance urography (MRU) is similar to computerized tomography (CT) scans except that MRUs require no ionizing radiation; this makes MRU an attractive option for use in the urinogenital tract and for both pediatric and pregnant patients (Leyendecker & Gianini, 2009)  As with all MR imaging techniques, the image is taken by putting the patient in a powerful magnetic field.  Because the strength of the field varies quickly with distance (a high “gradient”), the atoms in the body respond differently according to the distance and direction from the magnets.  This process can create an image of virtually the entire urinary tract in one test (O’Donoghue, McSweeney, & Jhaveri, 2010).  The key limitation of MRU for urinary imaging is that it is less reliable at detecting calcifications (i.e., kidney stones), and air; plus, it is less frequently used and therefore expertise in interpreting the images generated is less common (O’Donoghue et al., 2010).  In addition, it takes time and very specialized expertise to properly interpret the images, making it challenging to find personnel to execute the MRU (Khrichenko & Darge, 2010).

Typically, the MRU involves injecting an appropriate contrast agent to more clearly identify specific types of tissues such as blood vessels or tumors. Also, an MRU is often preceded by a low-dose of a mild diuretic to force the kidneys and bladder to be distended, which provides better view of those organs. Most commonly, the contrast agent is some type of chelate of gadolinium, although a patient experiencing renal shutdown cannot tolerate that contrast agent. A variety of scanning techniques differentiate among different types of tissues (water-bearing; fat-bearing; air/tissue boundaries;

MRUs can experience some side effects. First, any patient with a pacemaker or other implants are usually ineligible for MR imaging of any type because of the interaction of the implant with the extremely strong magnetic fields.  Some people also experience an itching or twitching of the nerves that derives from the rapid on/off cycling of the magnetic field.  Also, the equipment itself is extremely noisy so it is important that everyone around have some type of ear protection.  The urgent need to void the bladder due to the diuretic used to distend the urinary system  may disrupt the scan, so some labs catheterize the patients before doing the test (Khrichenko & Darge, 2010). Because the magnetic fields are so intense and so tightly constrained, the equipment tends to be claustrophobic for patients.  Babies and very young children may be sedated to keep them still during their scan (Leyendecker & Gianini, 2009).

Thesis Writing Process

  • Thinking and brainstorming
  • Preparing a proposal
  • Doing a research
  • Writing a thesis paper
  • Proofreading the document
  • Revising the thesis

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