ALS Amyotrophic Lateral Sclerosis: FDG-PET as Marker of Cerebral Involvement

Prof. Dr. Philip Van Damme, MD, PhD Neuromuscular Reference Center, Neurology Department, University Hospitals Leuven Vesalius Research Center, VIB, Leuven Leuven Institute of Neurodegenerative Disorders (LIND) KU Leuven, BelgiumMedicalResearch.com Interview with:
Prof. Dr. Philip Van Damme, MD, PhD
Neuromuscular Reference Center, Neurology Department, University Hospitals Leuven
Vesalius Research Center, VIB, Leuven
Leuven Institute of Neurodegenerative Disorders (LIND)
KU Leuven, Belgium

MedicalResearch.com: What are the main findings of the study?

Prof: Van Damme: Earlier FDG-PET studies carried out in the 80’ties already pointed out that patients with ALS had decrease glucose uptake in the brain that is more extended than the motor cortex, at least at the group level. Of course, this imaging technique has been improved since then.

We prospectively assessed the diagnostic and prognostic value of FDG-PET in patients that were referred to us because a diagnosis of ALS was suspected.

The most important finding of our study probably is that FDG-PET shows perirolandic and variable frontotemporal hypometabolism in most patients with ALS at the first presentation in our clinic. It suggests that FDG-PET is a very sensitive marker of cerebral involvement in ALS, which has a high sensitivity at the single patient level.

In addition our study revealed that the co-occurrence of extensive prefrontal or anterior temporal hypometabolism was present in about 10% of patients and had a negative effect on survival after disease onset.

MedicalResearch.com: Were any of the findings unexpected?

Prof: Van Damme:  Given the earlier studies with FDG-PET in ALS, we expected to find hypometabolism at the patient group level. However, the sensitivity of the abnormalities seen at the single patient level was quite unexpected.

Also, to find extensive regions of hypometabolism in the prefrontal and/or anterior temporal lobes in patients with ALS were you wouldn’t expect the co-occurrence of frontomporal dementia at first sight in about 10% of patients was remarkable. The detection of frontotemporal involvement becomes more and more important because it has consequences for the prognosis and management of the patients. FDG-PET may become an important ancillary test to look for frontotemporal involvement in patients with ALS, even if no cognitive or behavioral problems are reported by the patient and his or her family.
MedicalResearch.com: What should clinicians and patients take away from your report?

Prof: Van Damme: There is an unmet need for an imaging biomarker of disease in ALS, both from the diagnostic as well as from the prognostic point of view. FDG-PET may play its role herein, but further studies are needed to confirm this.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Prof: Van Damme:  Our results suggest that FDG-PET has diagnostic and prognostic value at the single patient level in ALS, but several questions remain unanswered. How specific is the finding of perirolandic and frontotemporal hypometabolism in ALS? It seems to be a very sensitive marker in patients with ALS, but we don’t know its specificity or its discriminative value for ALS mimic syndromes.

MedicalResearch.com: How good is the correlation between FDG-PET findings and neuropsychological scores?

Prof: Van Damme:  How early in the disease course do these changes appear? In our study we scanned the patients when they first presented at our center, but we don’t know if these changes are already present in earlier disease stages or even in the presymptomatic stage.

Citation:

Value of 18Fluorodeoxyglucose–Positron-Emission Tomography in Amyotrophic Lateral Sclerosis: A Prospective Study

Van Laere K, Vanhee A, Verschueren J, et al. Value of 18Fluorodeoxyglucose–Positron-Emission Tomography in Amyotrophic Lateral Sclerosis: A Prospective Study. JAMA Neurol. 2014;():. doi:10.1001/jamaneurol.2014.62.