Pyruvate: An in vivo marker of cestodal infestation of the human brain on proton MR spectroscopy

Abstract

Purpose: To study intracranial cestodal cysts using in vivo proton magnetic resonance spectroscopy ( 1 H MRS) in an effort to identify metabolite(s) that may help in recognizing the parasitic etiology and, perhaps, viability of such tapeworm cysts. Cestodal infestations of the human central nervous system (CNS)-cysticercosis and hydatidosis-are not rare. Identification of a scolex is considered diagnostic of cysticercosis on imaging. In its absence, however, the features are non-specific. Materials and Methods:Three patients with intracranial hydatid cysts and 13 patients with intracranial cysticercal cysts (four intraventricular, seven parenchymal, and two subarachnoid racemose cysts) were studied on a 1.5-T MR system. In vivo 1 H MRS was performed by multivoxel twodimensional hybrid chemical shift imaging technique (TE ϭ 135 msec). In vitro 1 H NMR and mass spectroscopy (matrix assisted laser desorption/ionization [MALDI]) were performed on excised cysticercal and hydatid cyst fluid. MALDI spectra for pyruvate and succinate were also obtained.Results: Alanine, pyruvate, and acetate were seen in all the three hydatid cysts. Lactate was seen in racemose cysticercal cysts. A large resonance at 2.4 ppm, confirmed as pyruvate at mass spectroscopy, was seen in 13 cestodal cysts. Pyruvate was not seen in one each of racemose, intraventricular, and parenchymal cysticercal cysts. Conclusion:Pyruvate is the predominant metabolite in cestodal cysts infesting the human CNS. It may be a marker of parasitic etiology and perhaps that of viability of such intracranial cysts.

Neurocysticercosis as Solitary Parenchymal Lesion Confirmed by Mitochondrial Deoxyribonucleic Acid Sequence Analysis-Case Report-

“…13,14) However, very few cases have been examined using these methods. 5,6,9,10,13,14) Here we present a case of neurocysticercosis identified by MR spectroscopy and confirmed as solitary parenchymal lesion caused by the Asian genotype of T. solium by mitochondrial DNA sequence analysis.…”

“…1,3) Recently, MR spectroscopy has been proposed as a useful method for the diagnosis of neurocysticercosis. 5,6,9,10) The combination of elevated lactate, alanine, succinate, and choline levels, and reduced NAA and creatine levels helped to characterize a cystic intraaxial lesion in the brain as neurocysticercosis. 9) Pyruvate is the predominant metabolite in cysticercosis cysts.…”

“…1,3) The larvae can cause cyst formation in any tissue, including the central nervous system (CNS). Cysticercosis in the CNS, or neurocysticercosis, is a very common disease in Central and South America, Asia, and Africa, [1][2][3][4][5][6][9][10][11][12][13][14] although a few cases have been reported in Japan. 7,8) Patients with neurocysticercosis often present with varied and non-specific symptoms including seizures and focal neurological deficits.…”

“…3) The clinical diagnosis of neurocysticercosis has been based on the patient history, radiographical findings, and pathological confirmation. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] Magnetic resonance (MR) imaging is also valuable for the diagnosis. However, T 1 -weighted MR imaging with gadolinium may show neurocysticercosis as a solitary parenchymal lesion, which cannot be differentiated from other solitary lesions including other types of parasites and tuberculosis.…”

“…Recently, MR spectroscopy has been reported to be useful for non-invasive diagnosis. 5,6,9,10) Mitochondrial deoxyribonucleic acid (DNA) sequence analysis of the specimens can also provide a definitive diagnosis. 13,14) However, very few cases have been examined using these methods.…”