Identification of diffuse and focal brain lesions by clinical magnetic resonance spectroscopy

Abstract

The purpose of this paper is to facilitate the comparison of magnetic resonance (MR) spectra acquired from unknown brain lesions with published spectra in order to help identify unknown lesions in clinical settings. The paper includes lists of references for published MR spectra of various brain diseases, including pyogenic abscesses, encephalitis (herpes simplex, Rasmussen's and subacute sclerosing panencephalitis), neurocysticercosis, tuberculoma, cysts (arachnoid, epidermoid and hydatid), acute disseminated encephalomyelitis (ADEM), adrenoleukodystrophy (ALD), Alexander disease, Canavan's disease, Krabbe disease (globoid cell leukodystrophy), Leigh's disease, megalencephalic leukoencephalopathy with cysts, metachromatic leukodystrophy (MLD), Pelizaeus-Merzbacher disease, Zellweger syndrome, HIV-associated lesions [cryptococcus, lymphoma, toxoplasmosis and progressive multifocal leukoencephalopathy (PML)], hydrocephalus and tuberous sclerosis. Each list includes information on the echo time(s) (TE) of the published spectra, whether a control spectrum is shown, whether the corresponding image and voxel position are shown and the patient ages if known. The references are listed in the approximate order of usefulness, based on spectral quality, number of spectra, range of echo times and whether the voxel positions are shown. Spectra of Zellweger syndrome, cryptococcal infection, toxoplasmosis and lymphoma are included, along with a spectrum showing propanediol (propylene glycol).

The in-depth evaluation of suspected mitochondrial disease

“…However, just as blood lactate levels have only a moderate sensitivity for mitochondrial disease, brain Lac peaks on MRS are also not highly sensitive. Two studies showed the sensitivity of Lac peaks in mitochondrial disease to be 18 % to 27% [34,35]. Lac peaks vary depending on whether a patient is undergoing an exacerbation of their disease [30], as well as whether their lesions are acute, subacute, or chronic [28].…”

“…Lac peaks vary depending on whether a patient is undergoing an exacerbation of their disease [30], as well as whether their lesions are acute, subacute, or chronic [28]. Detection of Lac signal may also depend on its concentration, as the threshold of detection by MRS is 0.5 mM to 1 mM [34,35]. Absence of a Lac peak similarly does not ruleout mitochondrial disease, as the specific tissues involved in mitochondrial disease vary, as does the location of brain involvement.…”

“…Absence of a Lac peak similarly does not ruleout mitochondrial disease, as the specific tissues involved in mitochondrial disease vary, as does the location of brain involvement. MRS specificity for mitochondrial disease is further limited by the possibility of other conditions giving rise to Lac peaks [35]. However, in the scenario of clinical and biochemical suspicion for mitochondrial disease, identification of a Lac peak would add weight to its possibility and potentially provide evidence to substantiate a more invasive diagnostic evaluation.…”

“…In some studies, the apparent decrease in the NAA/Cr signal was reversible [38,39]. As with elevated Lac, decreased NAA is not specific for mitochondrial, or even metabolic disease because other disorders may also present with NAA signal alterations [35,40]. However, additional clinical and biochemical evaluation may often segregate these disorders from primary mitochondrial disease.…”

Cerebral Lipid Accumulation Detected by MRS in a Child with Carnitine Palmitoyltransferase 2 Deficiency: A Case Report and Review of the Literature on Genetic Etiologies of Lipid Peaks on MRS

“…Mobile lipids, visible on MRS, can be seen in various acquired disorders, such as areas of necrosis within highgrade brain tumors (Kimura et al 2004;Delorme and Weber 2006), active lesions from demyelinating diseases such as multiple sclerosis (Wolinsky et al 1990;Near 2013), and infectious etiologies as in tuberculomas and toxoplasmosis (Kingsley et al 2006). Care should also be taken not to place the voxel too close to the skull, as this will capture the resonance from fat molecules in the diploe and scalp (Caruso et al 2004;Near 2013).…”