Magnetic Resonance Image and Blood Manganese Concentration as Indices for Manganese Content in the Brain of Rats

Abstract

Neurological disorders similar to parkinsonian syndrome and signal hyperintensity in brain on T1-weighted magnetic resonance (MR) images have been reported in patients receiving long-term total parenteral nutrition (TPN). These symptoms have been associated with manganese (Mn) depositions in brain. Although alterations of signal intensity on T1-weighted MR images in brain and of Mn concentration in blood are theoretically considered good indices for estimating Mn deposition in brain, precise correlations between these parameters have not been demonstrated as yet. Male Sprague-Dawley rats received TPN with 10-fold the clinical dose of the trace element preparation (TE-5) for 7 d. At 0, 2, 4, 6, and 8 wk post-TPN, the cortex, striatum, midbrain, and cerebellum were evaluated by MR images, and Mn concentration in blood and Mn content in these brain sites were measured by atomic absorption spectrometry. Immediately after TPN termination, signal hyperintensity in brain sites and elevated Mn content in blood and brain sites were observed. These values recovered at 4 wk post-TPN. A positive correlation was observed between either the signal intensity in certain brain sites or Mn content in blood and the relevant brain sites. Our observations suggest that the Mn concentration in blood and signal intensity in the brain sites on T1-weighted MR images are reliable indices for monitoring Mn contents in brain.

Identification of mineral deposits in the brain on radiological images: a systematic review

“…Of the 46 included papers, 40 studied iron [1-3, 5, 7, 15-50], 3 studied calcium [28,36,51], 1 studied copper [36] and 6 studied manganese [36,[52][53][54][55][56] deposition (see Table in the Electronic Supplementary Material).…”

“…We only found one study that confirmed histologically the MRI appearance of copper in four human brains as hyperintense on T1W and hypointense on T2W images [36]. Manganese was imaged at 4.7 T [53-56] and 1.5 T [52] in rodents and at 0.5 T and 1.5 T [33] in humans. In all cases the manganese was reported as hyperintense on T1W images.…”

“…Calcium was imaged in brain tumours [28] and in the brains of patients with hepatic cirrhosis [36] and MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) [51]. Manganese was generally imaged in the context of manganese toxicity after excessive dietary intake [53][54][55] or parenteral nutrition [52], although its presence was detected in a study of four deceased patients with hepatic cirrhosis along with other minerals [36] and in rodents with transient focal ischaemia [56]. Copper deposition was reported only in patients with hepatic cirrhosis [36].…”

Evaluation of indexes of in vivo manganese status and the optimal intravenous dose for adult patients undergoing home parenteral nutrition

“…In an in vitro study using manganese and trace element (iron, copper, zinc, and iodine) solutions diluted with physiologic saline or rat brain homogenate, Chaki et al (12) observed concentration-dependent signal hyperintensity only for the solutions that contained manganese; no effect was observed for solution without manganese. The same team also reported that certain brain sites in rats that received TPN showed a strong positive correlation between whole-blood manganese concentrations and the signal intensity on T 1 -weighted images (13). Thus, the general consensus is that during parenteral nutrition, T 1 shortening is due to manganese accumulation.…”

Atomic spectrometry update. Clinical and biological materials, foods and beverages

“…Two research groups reported studies on the determination of Mn in blood or tissues of rats and mice following administration of Mn compounds. Chaki et al 168 used AAS to determine Mn concentrations in blood and brain tissue of rats receiving total parenteral nutrition (TPN) with an elevated trace element content. The authors also used magnetic resonance imaging to examine signal hyperintensity in the brain.…”