However, it was never the position of any of us working with SPECT in children or adolescents that it's perfusion information should be considered "diagnostic" per se. Unfortunately, as much as we are building a very strong data base supporting the utility of SPECT in "evaluating" various psychiatric conditions, the current state of the art is such that it is useless to waste efforts purporting it to be "diagnostic" in a stand alone way. Thus, the APA's conclusion that "evidence does not support the use of brain imaging for clinical diagnosis or treatment of psychiatric disorders" isn't particularly earth-shattering. In fact, even with such well established neurological conditions such as stroke, pre-surgical seizure localization and dementia for which SPECT is approved by the American Academy of Neurology and in addition to stroke, pre-surgical seizure localization and dementia, for traumatic brain injury by the Society of Nuclear Medicine (1999), American College of Radiology and Medicare, its approval is limited to the ¨evaluation¨ of these conditions, not the "diagnosis". Diagnoses are always formulated by physicians taking into account all other clinically relevant information. In addition, most 3rd party carriers approve it only for the "evaluation" of these disorders, not the diagnosis, and they always require clinical correlation. Therefore, the statement of APA Council on Children, Adolescents and Their Families regarding "diagnosis" does not differ from our position which is consistent with both the ACR and SNM positions. When SPECT's database becomes strong enough for it to be approved for the "evaluation" of psychiatric disorders, similar to its neurological status, it will surely require clinical correlation. In fact, our extensive experience indicates that many complicated neuropsychiatric cases involve neurologic co-morbidities and it is here, at the current time, where SPECT has its greatest utility. Over 80% of patients we see in our brain imaging clinic for refractory "psychiatric" problems are found to have a complicating neurological condition, most commonly occult traumatic brain injury. With the remaining 20%, SPECT often proves to be useful for patients carrying multiple conflicting psychiatric diagnoses. Furthermore, with this population of complicated patients, we find a very high percentage of comorbid neurological conditions. We do not recommend SPECT for routine use in otherwise uncomplicated psychiatric patients. As psychiatrists, neurologists, developmental pediatricians and other neurobehavioural physicians working with neuropsychiatric patients well know, a large proportion of "treatment-refractory" psychiatric patients have undiagnosed neurologic conditions. SPECT provides valuable data which can help to sort out these various overlapping neurobiological processes.

A few illustrative examples would include: 1) an adolescent who was diagnosed as schizophrenic because of "hallucinations" regarding spiritual experiences or conversations with God or the devil, but was not responding to multiple antipsychotics, proved based on a SPECT scan to have a right (non-dominant) temporal lobe seizure disorder, 2) the case of a child misdiagnosed with Intermittent Explosive Disorder, unresponsive to treatment, in whom SPECT identified an occult seizure disorder who, when treated with anticonvulsants, was essentially "cured", 3) the case of an adolescent diagnosed with Bipolar Disorder, again refractory to treatment, in whom SPECT identified the presence of thinned cortex and markedly enlarged ventricles, prompting an MRI which, together with clinical data, resulted in a diagnosis of Schizophrenia, 4) although not indicated for the evaluation of suspected tumors, SPECT has identified various brain tumors in many so-called refractory "psychiatric" cases, and 5) a child diagnosed with ADHD, refractory to treatment, in whom SPECT demonstrated severe traumatic injury to her frontal lobes as result of occult physical abuse going on in the home. Therefore, a physician legitimately might consider ordering a SPECT scan in a refractory or complicated "psychiatric cases" to rule out occult, comorbid neurological abnormalities.

Furthermore, the APA committee overstates the relative risk of radiation exposure related to SPECT scans. The whole body radiation exposure in one scan is approximately 0.26 rems and, in the 2 scan protocol typically used in neuropsychiatric patients, it is 0.52 rems. The position of the committee is a typical one found among American physicians. Physicians, particularly pediatricians, like most Americans, are "nuclear-phobic". Whenever the term appears, many physicians overreact inappropriately. When MRI first became available, it was referred to as NMR or, Nuclear Magnetic Resonance imaging. Few clinicians wanted to use it. When they changed the name to Magnetic Resonance Imaging, it became much more widely accepted. Similarly, with CT or CAT scans- the names sound benign and conjure up images of people's pets. However, the fact is that clinicians, including many Pediatricians, order over 500,000 head CT's in America each year on children. Average whole body radiation exposure: 6.0 rems, over 20 times that of a brain SPECT. While they are reluctant to utilize brain SPECT in their evaluation of children, at the same time, they order thousands of studies utilizing radiation doses that are orders of magnitude greater- (abdominal CT scans= 2.5 rems, fluoroscopy, such as upper GI studies and barium enemas range between 2.0 and 4.0 rems.

Clearly, "nuclear-phobia" is alive and well in the pediatric and psychiatric communities. We strongly recommend that you consider the words of the out-going president of the Society of Nuclear Medicine, Michael D Devous, Sr., Ph.D., (2002):

" …clarify that in fact SPECT and PET procedures have no more risk than MRI-based procedures.... Indeed, there are no data that have ever demonstrated any harm to humans by radiation exposure at diagnostic imaging levels. In fact, current data support the presence of radiation hormesis: that low levels of radiation exposure induce beneficial effects of cellular repair and immune system enhancement....... Therefore it should be concluded that neither SPECT nor PET brain imaging procedures are associated with any particular risk over activities of daily living and certainly should not be considered to be any more risky than MRI or any of its associated functional imaging derivatives."

Moreover, numerous errors of fact were evident in the report of the Council on Children, Adolescents, and Their Families. For example, SPECT perfusion studies do not provide direct data on glucose utilization. Rather, SPECT perfusion provides data on regional brain perfusion which is tightly correlated with regional brain activity. The Council described the resolution of SPECT as being inferior to PET; however, newer generation SPECT cameras, such as the NeuroQuad four-headed camera, provides a intrinsic spatial resolution of 2.4 mm, which is superior to the typical resolution of PET (4.0 mm).

The Council indicates that the lack of normative databases is a limiting factor of the utility of SPECT scans. We agree with this statement. A normative database for statistical parametric analysis was incorporated into the Segami Corporation SPECT software over the past five years. This rigorously defined population of normals was developed by one of the authors, Dr. Ismael Mena. Statistical parametric analysis and population comparison is now a standard part of a SPECT scan interpretation among the authors.

SPECT's utility in helping to differentiate between ADHD and childhood Bipolar Disorder has been recognized in clinical practice. When you consider that the mortality rate of this condition approaches 20% and higher, one can certainly justify the risk/benefit ratio as promulgated in the position paper of the American Academy of Pediatrics, Committee on Environmental Health, Risk of Ionizing Radiation Exposure to Children: A Subject Review, (Pediatrics, 101:717-719, 1998) on the use of isotopes in children.

As much as we agree that SPECT is not "diagnostic" for any medical condition, and we do not advocate SPECT for the routine evaluation of uncomplicated psychiatric cases, we strongly object that it can play no role at all in the evaluation of the more complicated childhood neuropsychiatric cases. We are concerned that your position as advocated, will inappropriately discourage the parents of many children and adolescents from obtaining brain SPECT imaging when it would be indicated, which ultimately may prove more harmful than helpful to thousands of children.

We strongly recommend that the APA reconsider its inaccurate, uninformed position regarding the appropriate use of SPECT in the evaluation of complicated pediatric neuropsychiatric cases.

Sincerely,
S. Gregory Hipskind MD PhD
Chief Medical Officer, Brain Matters, Inc.
Nuclear Neurology License 1057-0
E-mail: sghipskind@brainmattersinc.com

Theodore A. Henderson, M.D., Ph.D
Associate Medical Director and Director of Neurobehavioral Research
Child, Adolescent, and General Psychiatrist
Brain Matters, Inc.
E-mail: thenderson@brainmattersinc.com

Ismael Mena, M.D.
Professor Emeritus of Radiological Sciences
UCLA School of Medicine
Doctor Honoris Causa
University of Auvergne, France.
E-mail: imenamd@aol.com