N-Isopropyl-<i>p</i>-¹²³I-Amphetamine Single Photon Emission Computer Tomography in Motor Neuron Disease

Abstract

N-Isopropyl-p-¹²³I-amphetamine (¹²³I-IMP) single photon emission computer tomography studies were performed on 17 patients suffering from amyotrophic lateral sclerosis (ALS). All patients displayed varying degrees of impaired fixation of ¹²³I-IMP in the whole brain. These findings were not related to the clinical variants of ALS and the age of the patients. A correlation between the severity of the disease and the degree of impaired fixation could be observed. In addition, patients suffering from ALS for longer periods showed more pronounced impairment of ¹²³I-IMP fixation.

Amyotrophic lateral sclerosis

“…Later, its relation to Pick's disease was clinically and neuropathologically described [24] and became textbook knowledge [25]. However, this knowledge was partially forgotten and further explored clinically only after half a century [26][27][28][29] and is now widely accepted. It is interesting to note that the frontal deficits do not seem to progress as fast as the motor deficits in most ALS patients [30]; therefore it seems likely that frontal deficits do not have a major impact on end-of-life decisions.…”

Amyotrophic Lateral Sclerosis

“…Early and longitudinal studies with PET in ALS using 18 F-fl uorodeoxyglucose as a surrogate for cerebral metabolism (regional cerebral metabolic rate for glucose -rCMRGIc) confi rmed widespread and progressive reductions in those ALS patients with clinical UMN signs (Dalakas et al 1987 ). This was linked to neuropsychological defi cits of a frontal lobe nature in ALS patients, Sawada et al ( 1988 ) 17 ALS (1 FU after 9 months); 15 disease controls Widespread uptake reduction, correlated with disease severity and duration Ludolph et al ( 1989 ) 1 ALS (16-month FU) Extension of uptake reduction from PMC to frontal lobes over scan interval Waragai et al ( 1997 ) 99m Tc-HMPAO 4 ALS-dementia Reduced frontal lobe uptake ( postmortem details included) Neary et al ( 1990 ) 14 ALS; 14 HC 8/14 prominently reduced frontal lobe uptake (3 with dementia, 1 with aphasia) Waldemar et al ( 1992 ) 18 ALS; 8 disease controls Categorisation into four groups by reduced uptake:…”

“…Early SPECT in ALS used the tracer N-isopropyl-p- This revealed widespread cortical reductions, pronounced in those with longer disease duration (Ludolph et al 1989 ) (Fig. 29.1 ).…”

Cognitive impairment, frontotemporal dementia, and the motor neuron diseases

“…ALSci language characteristics include word‐finding difficulty, lexical disorganization, and reliance on stereotypical sentences. Anterior‐based language functions (eg, fluency, syntax, and grammar) are compromised 12, 13…”

“…In addition to the precentral gyrus atrophy that is well recognized in ALS, neuroimaging in ALSci demonstrates a more widespread frontal and temporal cortical atrophy, with variable involvement of the precentral and postcentral gyrus, the anterior cingulate gyrus, corpus callosum, and brainstem tegmentum. Functional neuroimaging techniques, including single‐positron emission tomography studies with either 123 I‐ N ‐isopropyl‐ p ‐iodoamphetamine12, 15 or 99m Tc‐ d , l ‐hexamethylproplene–amine oxime (HM‐PAO),16, 17 and positron emission tomography, are sensitive to reduced frontal and temporal cortical blood flow in ALSci 18. Reductions in the N ‐acetylaspartase to creatine ratio of anterior cingulate gyrus neurons with the use of proton magnetic resonance spectroscopy has been shown to be a sensitive marker of ALSci 6…”