Renal imaging

Technetium-99m mertiatide (A/-[Ai-[A/-[(benzoylthio)acetyl]glycyl]glycine) is a renal imaging agent. It is excreted by the kidneys via active tubular secretion and glomerular filtration. The kit vial is reconstituted by using 740—3700 MBq (20—100 mCi) of Tc pertechnetate and boiling for 10 minutes. 

Radiopharmaceuticals are the preferred agents for the assessment of function, as opposed to structure. Renal imaging agents are classic examples in that sense, since they allow the monitoring of the imaging of glomerular filtration and tubular secretion functions of the kidneys. Currently there are two agents available one is Tc-DTPA of unknown structure, and the other one is the... 

Figure 54 Renal images obtained using 99raTc-DTPA showing a normal right kidney and impaired function of the left kidney. The 4 "Tc activity can be seen to accumulate in the bladder at the bottom centre with increasing elapsed time from (a) to (c). (Courtesy of the Nuclear Medicine Department, Queen Elizabeth Hospital, Birmingham, UK)...

The structure of [TcO(EDTA)] is illustrated in Fig. 2 and shows the Tc(V) to be seven-coordinate106. Stable, highly water soluble ions such as this are fairly readily eliminated by the kidneys and this structure may be relevant to the renal imaging agents employing EDTA and DTP A. 

Fig. 4 Novel [99mTc(CO)3]+ based complexes for renal imaging...

Ronnhedh C, Jacquenod M, Mather LE (1996) Urineless estimation of the glomerular filtration rate and renal plasma flow in the rat. J Pharm Tox Methods 36 123-129 Sapirstein LG, Vidt DC, Mandell MJ, Hanusek G (1955) Volumes of distribution and clearances of intravenously injected creatinine in the dog. Am J Physiol 181 330-336 Sarkar SK, Holland GA, Lenkinski R et al. (1988) Renal imaging studies at 1.5 and 9.4 T effects of diuretics. Magn Reson. Med 7 117-124... 

Renal imaging agents which exhibit mixed behaviour may be useful in the study of kidney... 

ERPF can also be measured using the radioisotopes I-orthoiodo-hippurate or Tc-mercaptoacetyltriglycine. One important advantage of this method is its ability to measure ERPF in total or for each kidney independently, as well as its ability to produce renal images. Russell and Dubovsky, using a single-injection technique, compared clearance methods with and without urine collection and showed similar results with each method. 

Mindell HJ, Fairbank IT. Renal imaging techniques. In Greenberg A, ed. Primer on Kidney Diseases, 2nd ed. San Diego, Acadenfic Press, 1998 47-53. 

Figure 3. Renal imaging criteria of analgesic nephropathy as observed in CT scan without contrast material, including a decreased renal size, bumpy contours, and papillary calcifications.

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