Ismael Mena

Ismael Mena, MD, (d. 15 February 2015) specialized in Nuclear Medicine. He was a Professor Emeritus of the UCLA School of Medicine; Doctor Honoris Causa of the Auvergne University, France; and received honor distinctions from the Association of Latin American Societies of Biology and Nuclear Medicine (ALASBIMN) in 2002 (Santiago, Chile) and 2005 (Montevideo, Uruguay). He was particularly interested in using the latest nuclear medicine imaging to measure functional brain flow in patients with brain degenerative diseases.

He is one of the authors of the 2011 case definition, International Consensus Criteria.

Notable Studies

• 1997, NeuroSPECT Findings in Children with Chronic Fatigue Syndrome

  Abstract - "Background: NeuroSPECT studies have described specific abnormalities in cerebral perfusion in adults with criteria for Chronic Fatigue Syndrome. This reports findings in 13 children with criteria for Chronic Fatigue Syndrome. Objective: NeuroSPECT findings in 13 CFS/CFIDS children. Methods: Thirteen children meeting CDC criteria for CFS/CFIDS, were evaluated using NeuroSPECT imaging utilizing Xenon 133 and Tc-99m-HMPAO(l). Results: In 13 children, hypopcrfusion was observed at 42 ± 10 ml/min/100g, p < 0.0001 in the left temporal lobe and at 45 ± 11, p < .001 in right temporal lobe. Statistically significant hypoperfusion was also observed in both parietal lobes and at 50 and 53 ml/ min/lOOg, p < 0.05 in the frontal lobe of the right hemisphere. Quantitated HMPAO demonstrated bilateral orbitofrontal and anterior temporal hypoperfusion. There was also hypoperfusion in the dorsal aspects of both frontal lobes and both parietooccipital lobes. Conclusion: NeuroSPECT is presented as a quantifiable, reproducible tool that can allow us to document a cohort of children defined as CFS/CFIDS."

• 1995, The Assessment of Vascular Abnormalities in Late Life Chronic Fatigue Syndrome by Brain SPECT: Comparison with Late Life Major Depressive Disorder

  Abstract - "We report on brain SPECT analysis of regional cerebral blood flow (rCBF) in late life chronic fatigue syndrome (CFS) patients and compare their results with patients with late life depression and elderly normal controls 45 years and older. We attempted to distinguish CFS from normals and patients with depression and applied the findings to understand the pathophysiology of the illness. We studied 33 patients with CFS (55 ± 10 years), 26 patients with late life depression (62 ± 8 years), and 19 normal controls (66 ± 8 years); 43 other normal controls had only ¹³³Xe rCBF measurements (66 ± 8 years). We evaluated rCBF quantitatively with ¹³³Xe images and qualitatively with high resolution imaging using 99mTc-HMPAO. We found that rCBF in CFS measured by ¹³³Xe varied between 35 and 41 ml/min/l00g in both hemispheres, p < 0.0001 and 0.05; similar findings were observed in depression. In CFS 99mTc-HMPAO imagain demonstrated right orbitofrontal and marked right dorsofrontal hypoperfusion at 58% to 66% of the maximal activity in the brain, p , 0.001. In late life depression, hypoperfusion was primarily limited to the right orbitofrontal lobe, 42% and 57%, p , 0.001. In depression, the abnormalities were most striking in the left temporal lobe and particularly in the left anterior frontal lobes. CFS patients with major depressive disorder by DMS-III-R criteria did not differ in regional cerebral hypoperfusion from those without major depression. The pathophysiology of the illness may involve the dysregulation of a neural network which includes circuits between the hippocampus (located in the anterior temporal lobe) and the dorsolateral prefrontal cortex."

Learn More

• 2015, Obituary

cerebral 1. of or relating to the brain or the intellect 2. of, relating to, affecting, or being the cerebrum.

Chronic Fatigue and Immune Dysfunction Syndrome (CFIDS) - Chronic Fatigue and Immune Dysfunction Syndrome is another term for Chronic Fatigue Syndrome, but one which emphasizes the immunological aspects of the disease. Popular in the 1990s, this term has apparently fallen into disuse.

Centers for Disease Control and Prevention (CDC) - The Centers for Disease Control and Prevention is a U.S. government agency dedicated to epidemiology and public health. It operates under the auspices of the Department of Health and Human Services.

limbic cortex Part of the brain (within the cerebral cortex) involved in emotion, memory and behavior. Part of the limbic system.

regional cerebral blood flow (rCBF) - The amount of blood flow to a specific area of the brain in a particular period of time.

regional cerebral blood flow (rCBF) - The amount of blood flow to a specific area of the brain in a particular period of time.

myalgic encephalomyelitis (M.E.) - A disease often marked by neurological symptoms, but fatigue is sometimes a symptom as well. Some diagnostic criteria distinguish it from chronic fatigue syndrome, while other diagnostic criteria consider it to be a synonym for chronic fatigue syndrome. A defining characteristic of ME is post-exertional malaise (PEM), or post-exertional neuroimmune exhaustion (PENE), which is a notable exacerbation of symptoms brought on by small exertions. PEM can last for days or weeks. Symptoms can include cognitive impairments, muscle pain (myalgia), trouble remaining upright (orthostatic intolerance), sleep abnormalities, and gastro-intestinal impairments, among others. An estimated 25% of those suffering from ME are housebound or bedbound. The World Health Organization (WHO) classifies ME as a neurological disease.