A preliminary study of neuroSPECT evaluation of patients with post-traumatic smell impairment

Abstract

BackgroundMost olfactory testings are subjective and since they depend upon the patients' response, they are prone to false positive results. The aim of this study was to use quantitative brain perfusion SPECT in order to detect possible areas of brain activation in response to odorant stimulation in patients with post-traumatic impaired smell in comparison to a group of normal subjects.MethodsFourteen patients with post-traumatic impaired smell and ten healthy controls were entered in this prospective study. All subjects underwent brain SPECT after intravenous injection of 740-MBq 99mTc-ECD and 48 hours later, the same procedure was repeated following olfactory stimulus (vanilla powder).ResultsIn most of seven regions of interest (Orbital Frontal Cortex, Inferior Frontal Pole, Superior Frontal Pole, Posterior Superior Frontal Lobe, Parasagittal Area, Occipital Pole, and Cerebellar area) the post-stimulation quantitative values show increased cortical perfusion being more pronounced in normal volunteers than the anosmic patients (except cerebellar areas and the right occipital pole). Maximal activation was observed in orbitofrontal regions (right+ 25.45% and left +25.47%).ConclusionBrain SPECT is a valuable imaging technique in the assessment of post-traumatic anosmia and could be competitive as an alternative to other imaging techniques, especially when functional MRI is unavailable or unsuitable. However, this procedure may benefit from complementary MRI or CT anatomical imaging.

Brain perfusion imaging with voxel-based analysis in secondary progressive multiple sclerosis patients with a moderate to severe stage of disease: a boon for the workforce

“…Lower metabolic activity of the cerebral region secondary to neuronal loss (due to the demyelination process) might decrease CBF. Neuronal loss may originate from hypoperfusion, iron deposition, demyelination, or Wallerian degeneration [ 33 ]. Neuronal metabolic dysfunction secondary to inflammation with consequent mitochondrial dysfunction may decrease the demand for blood supply and eventually brain perfusion [ 29 ].…”

“…Neuronal metabolic dysfunction secondary to inflammation with consequent mitochondrial dysfunction may decrease the demand for blood supply and eventually brain perfusion [ 29 ]. Axonal transection in the demyelination lesion of the white matter could result in anterograde and retrograde degeneration of axons that are associated with neuronal dysfunction and will consequently decrease GM perfusion [ 33 ]. An abnormal cerebral vasculature is another possible mechanism of the GM hypoperfusion [ 29 ].…”

“…Furthermore, inflammatory vascular edema may interfere with vascular blood flow following focal tissue swelling; whereas acute and chronic venous obliterations may develop as a result of exudation of inflammatory cells and intravascular fibrin deposition [ 34 ]. In addition, obliterative vasculitis might cause chronic ischemia resulting from modulation of the vascular tone and the CBF [ 33 , 35 ]. An increase in the calcium concentration of extracts, neuronal and glial cells shown in MS lesions may be associated with an increase in the tone of blood vessels.…”

Dysosmies et dysgueusies post-traumatiques : aspects médicolégaux

“…Elle n'est pas de pratique courante, tout comme l'électro-encéphalo-graphie olfactive [11], la photon emission computed tomography (SPECT) ou l'IRM fonctionnelle cérébrale [12]. Ces deux dernières techniques d'imagerie cérébrale couplées à une appréciation de l'activité olfactive semblent prometteuses [13,14]. Le pronostic des dysosmies est fonction de l'étiologie ; l'apparition secondaire d'une cacosmie ou d'une parosmie est de pronostic favorable.…”

Olfaction and traumatic head injury - Is it possible to discriminate between malingering and patients with smell disorders based on nowadays knowledge?

“…Some authors sustain the fact that SPECT may be more efficient than FMRI; for example, the orbitofrontal cortex is better visualized by SPECT than FMRI. Thereby, signal distortions could appear due to its location near the skull base 54 . Other techniques that may be useful are: positron emission tomography (PET) [55][56][57] and magnetic source imaging (MSI) based on magneto-encephalography 58,59 .…”