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Solution to Picture of the week #6, and this week’s image. October 23, 2007

Posted by tomography in Megaureter, Nuclear Medicine, Picture of the week.
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megaurether.jpg Last week’s image was taken during a dynamic renal scan, and the image obtained was a so called renogram. During this technique metastable 99-Technetium labeled mercapto-acetyl-triglicine (MAG-3) is administered intravenously to the patient, and (s)he is placed under a gamma camera. The tracer, MAG-3, travels through the bloodstream, and (if the renal perfusion is adequate) it is excreted by the kidneys. As the traces travels, it emits gamma rays, that are recorded by the gamma camera. On average, data is collected for ten seconds for an image, during which, individual gamma photons are allowed to “stain” the diagnostic picture. Generally, the longer the tracer “stays” in one place (due to an obstruction for example), the more gamma photons will contribute to the stain for the given location. So if the configuration of the kidney-ureter-bladder system is physiological, it will have more staining in the pelvis of the kidney, and the bladder, but the ureter will not show, given that the speed of each bolus is normal, which is about 15-20 mm/second.

The correct answer was, indeed, megaureter as all of you correctly suggested. You may read a very detailed review on the subject via this link, or you may wait until I post my next topic titled “How to detect a megaureter?”

And now, here is this week’s image. Good luck, and see you back here next time!