02 Laboratory Testing and Imaging

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The American Psychiatric Publishing Textbook of Psychiatry, Fifth Edition. Edited by Hales RE, Yudofsky SC,

Gabbard GO. 2008 American Psychiatric Publishing, Inc. All rights reserved. www.appi.org1

Slide show includes

Topic Headings

Tables and Figures

Key Points

Laboratory Testing and ImagingStudies in PsychiatryH. Florence Kim, M.D., Paul E. Schulz, M.D.,

Elisabeth A. Wilde, Ph.D., Stuart C. Yudofsky, M.D.

The American Psychiatric Publishing

TEXTBOOK OF PSYCHIATRYFifth EditionEdited by Robert E. Hales, M.D., M.B.A., Stuart C. Yudofsky, M.D., Glen O. Gabbard, M.D.

2008 American Psychiatric Publishing, Inc. All rights reserved. www.appi.org

CHAPTER 2


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CHAPTER 2 Topic Headings

APPROACH TO SCREENING LABORATORY

AND DIAGNOSTIC TESTING OF PSYCHIATRIC

PATIENTSScreening Laboratory Testing

Screening Chest Radiographs

Screening Electrocardiograms

Screening Electroencephalograms

Screening Structural Neuroimaging Examinations

Overall Role of Screening Laboratory and

Diagnostic Testing

LABORATORY APPROACH TO SPECIFIC CLINICAL

SITUATIONS IN PSYCHIATRY

New-Onset PsychosisMood Disturbance: Depressive or Manic Symptoms

Anxiety

Altered Mental Status

Cognitive Decline

Dementias

Mild Cognitive Impairment

Substance Abuse

MEDICATION MONITORING AND MAINTENANCE

Mood StabilizersTricyclic Antidepressants

Neuroleptics

PHARMACOGENETICS AND PHARMACOGENOMICS

CEREBROSPINAL FLUID STUDIES

INVESTIGATIONAL BIOLOGICAL AND GENETICMARKERS

NEUROENDOCRINE TESTING

ELECTROPHYSIOLOGICAL TESTING

Standard Electroencephalogram

Polysomnography

Evoked Potentials

Quantitative EEG

NEUROIMAGING STUDIES IN PSYCHIATRY

Structural Neuroimaging Modalities

Computed Tomography

Magnetic Resonance Imaging

Comparison of CT and MRI

Clinical Use of CT and MRI in PsychiatryOther Structural Imaging Techniques

Magnetic Resonance Spectroscopy

Diffusion Tensor Imaging

Functional Neuroimaging Modalities

Single Photon Emission Computed Tomography

Positron Emission Tomography

Comparison of SPECT and PET

Clinical Use of PET and SPECT in Psychiatry

Cognitive Decline and Dementia

EpilepsyStroke

Traumatic Brain Injury

Neuroreceptor Imaging

Functional Magnetic Resonance Imaging

Magnetoencephalography

Neuroimaging of Psychiatric Disorders

CONCLUSION


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CHAPTER 2 Tables and Figures

Table 21. Selected medical conditions with psychiatric manifestations

Table 22. Useful screening labs in the workup of the neuropsychiatric patient

Table 23. Recommended diagnostic workup for a patient with new-onset psychosis

Table 24. Recommended diagnostic workup for a patient with new-onset depressive or manic symptoms

Table 25. Recommended diagnostic workup for a patient with new-onset anxiety symptoms

Table 26. Recommended diagnostic workup for a patient with altered mental status

Table 27. Recommended diagnostic workup for a patient with cognitive decline

Table 28. Substances of abuse

Table 29. Medication monitoring

Table 210. Psychiatric drug metabolism by specific P450 enzymes

Table 211. Drug metabolizer phenotype classification

Table 212. Selected investigational biological and genetic markers

Figure 21. Computed tomography (CT) tissue attenuation values and appearance.

Table 213. Tissue signal on T1 versus T2 weighting

Figure 22. MRI comparison axial cuts, bipolar disorder patient versus matched control.

Table 214. Comparison of computed tomography (CT) and magnetic resonance imaging (MRI)

Figure 23. Side-by-side comparison of structural imaging modalities: CT and MRI.

Table 215. Indications for computed tomography (CT), prior to or instead of magnetic resonance imaging (MRI)

(continued)


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CHAPTER 2 Tables and Figures (continued)

Figure 24. Diffusion tensor imaging (DTI).

Figure 25. Diffusion tensor imaging (DTI) in traumatic brain injury and bipolar disorder.

Table 216. Comparison of SPECT, PET, and fMRI

Figure 26. Side-by-side comparison of structural and functional neuroimaging: magnetic resonance imaging

(MRI) and positron emission tomography (PET).

Figure 27. Side-by-side comparison of single photon emission computed tomography (SPECT) versus

positron emission tomography (PET).

Figure 28. Structural magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging

of a healthy control subject and a patient with traumatic brain injury.

Figure 29. Structural magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging

of a patient with hypoxic brain injury.

Figure 210. Single photon emission computed tomography (SPECT), structural magnetic resonance

imaging (MRI), and magnetoencephalography (MEG) imaging of a patient with traumatic brain injury.

Figure 211. Neuroreceptor imaging.

Figure 212. Functional magnetic resonance imaging of working memory.

Figure 213. Functional magnetic resonance (fMRI) and transcranial magnetic stimulation (TMS) as a

neuroscience tool.

Table 217. Summary of neuroimaging findings in selected psychiatric disorders

Summary Key Points


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TABLE 21. Selected medical

conditions with psychiatricmanifestations

Table 21 lists some of the many

medical and neurological illnesses that

may present with prominent

neuropsychiatric symptoms. Clinical

laboratory assessment and diagnostic

testing can help determine which of themany potential causes is responsible

for a patients symptoms. Because a

number of these etiologies may have

potentially curative remediations,

accurate diagnosis is critical.

Source.Adapted from Ringholz 2001; Sadock and Sadock

2007; Wallach 2000.

(continued)


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TABLE 21. (continued)


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TABLE 22. Useful screening labs in the workup of the neuropsychiatric patient

Table 22 presents a list of screening laboratory tests that clinicians often use during the initial

evaluation of the patient with psychiatric complaints.

Source. Adapted from Alpay and Park 2000; Anfinson and Stoudemire 2000; Fadem and Simring 1998; Methodist Health Care System 2001;

Sadock and Sadock 2007; Wallach 2000.(continued)


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The American Psychiatric Publishing Textbook of Psychiatry, Fifth Edition. Edited by Hales RE, Yudofsky SC,Gabbard GO. 2008 American Psychiatric Publishing, Inc. All rights reserved. www.appi.org

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TABLE 23. Recommended diagnostic

workup for a patient with new-onset

psychosis

A careful evaluation is important for a patient with a

first episode of psychosis in order to rule out the

many possible medical and neurological causes of

psychosis. Table 23 summarizes some of the

recommended tests in the diagnostic approach to a

patient with new-onset psychosis.


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TABLE 24. Recommended diagnostic

workup for a patient with new-onsetdepressive or manic symptoms

Neuroimaging and electroencephalography are often helpful as well in understanding the etiology of

a patients mood symptoms. Multiple neurological and medical disorders have mood manifestations

that may often be the presenting complaint. The diagnostic approach to a patient with new-onset

depressive or manic symptoms is summarized in Table 24.


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TABLE 25. Recommended

diagnostic workup for a patient with

new-onset anxiety symptoms

Many different medical diseases can manifest anxiety, including angina and myocardial infarction,

mitral valve prolapse, substance intoxication and withdrawal, and metabolic and endocrine

disorders such as thyroid abnormalities, pheochromocytoma, and hypoglycemia. Neurological

disorders, such as many forms of dementia, can also present with anxiety. The diagnostic approach

to a patient with new-onset anxiety is summarized in Table 25.


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TABLE 26. Recommended

diagnostic workup for a patient with

altered mental status

Patients with a fluctuating mental status of acute

onset most likely will have one or more

underlying medical or neurological causes for

their impaired consciousness. This often

constitutes a medical emergency, and

comprehensive laboratory and diagnostictesting are indicated on an emergency basis, as

summarized in Table 26.


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TABLE 27. Recommended diagnostic workup for a

patient with cognitive decline

Table 27 lists the laboratory and diagnostic tests that

would be included in the workup of a patient with cognitive

impairment.


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TABLE 28. Substances of abuse

The length of time that a drug of abuse is detectable in the urine varies depending on the amount and

duration of substance consumed, kidney and liver function, and the specific drug itself. Table 28

reviews common drugs of abuse, toxic levels, and length of detection time.

Source. Adapted from Wallach 2000.


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TABLE 29. Medication monitoring

Although no clear consensus exists regarding appropriate clinical screening and monitoring regimens during

mood stabilizer treatment, a potential set of guidelines, which most authors appear to support, is listed in

Table 29. The table shows the psychotropic medications for which therapeutic drug monitoring may be

useful, as well as therapeutic and toxic drug levels and ancillary tests that are recommended to monitor for

the prevention of end-organ damage.

Source. Adapted from Wallach 2000; Hyman SE, Arana GW, Rosenbaum JF. Handbook of Psychiatric Drug Therapy, 3rd Edition. Boston, MA, Little, Brown & Co., 1991.

Used with permission.

0


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TABLE 210. Psychiatric drug metabolism by

specific P450 enzymes

Table 210 lists many of the psychiatric drugs that are

metabolized by selected CYP enzymes (substrates) as

well as those that may decrease enzyme activity

(inhibitors). CYP drug metabolism is highly variable

due to several factors, including genetic

polymorphisms, effects of concomitant medications(inhibition or induction of enzymes), physiological or

disease status, and environmental or exogenous

factors such as toxins and diet.

Source. Data adapted from Kirchheiner et al. 2001; Streetman 2000.


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TABLE 211. Drug metabolizer phenotype classification

Four general phenotypes have been used to describe the outcomes of CYP genetic polymorphisms

(Table 211): ultrarapid metabolizers, extensive metabolizers, intermediate metabolizers, and poor

metabolizers. Extensive metabolizers have the normal two copies of fully active CYP enzyme alleles for a

particular microsomal enzyme. Poor metabolizers do not have the active enzyme gene allele, resulting in

increased concentrations of medications due to reduced metabolism, and may have more adverse effects

at usual, recommended dosages. In contrast, ultrarapid metabolizers will have multiple copies of thefunctional enzyme allele, resulting in increased rate of drug metabolism, and may not reach therapeutic

concentrations at the recommended dosage.

Source. Adapted from Ingelman-Sundberg 1999; Mrazek 2006.


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TABLE 212. Selected investigational biological and genetic markers

There is considerable interest in isolating biological markers for psychiatric illnesses for the purposes

of improving the accuracy of diagnosis, predicting treatment response, identifying patients at risk, and

ultimately preventing the development of these disorders. Table 212 lists some of the biomarkers

being researched at this time.

(continued)


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FIGURE 21. Computed tomography (CT) tissue attenuation values and appearance.

CT scanning enlists a focused beam of X-rays that passes through the brain at many angles. The many

images evoked are then joined together to provide a cross-sectional view of the brain. The X-rays are

attenuated as they pass through tissue, which absorbs their energy. The degree of energy absorbed

varies, based on the radiodensity of the tissue. This differential X-ray attenuation is transformed into a

two-dimensional grayscale map of the brain by computers, with bone appearing most radiopaque, or

white, and air the least radiopaque, or black. Brain tissue, CSF, and water have varying degrees ofradiopacity (Figure 21).

Source. Adapted from J Levine lecture Structural Neuroimaging in Psychiatry, given as part of the Neuroimaging in Psychiatry lecture series,Department of

Psychiatry, Baylor College of Medicine, March 2006.


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TABLE 213. Tissue signal on T1 versus T2 weighting

In clinical practice, T2-weighted images can be very useful for visualizing lesions because they show

edema as an increase in signal intensity. T1-weighted images are useful for demonstrating structural

anatomy. Table 213 lists the characteristic appearance of tissue signals on T1- and T2-weighted MRI

images.

Source. Adapted from J Levine lecture Structural Neuroimaging in Psychiatry, given as part of the Neuroimaging in Psychiatry lecture series, Department of Psychiatry,

Baylor College of Medicine, March 2006.


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TABLE 214. Comparison of computed tomography (CT) and magnetic resonance

imaging (MRI)

MRI has many advantages over CT. First and foremost, it has superior visualization of brain tissue,

providing enhanced gray/white matter discrimination versus CT and allowing quantitative or volumetric

measurement of brain regions. Deep brain structures such as the cerebellum and brain stem are better

visualized with MRI. Furthermore, axial, coronal, and sagittal images may be acquired. MRI image

acquisition is complex, and depending on parameters, can produce T1-, T2-, or proton density

weighted images, spin-echo, and inversion-recovery images. Table 214 provides a summarycomparison of CT and MRI imaging modalities.


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FIGURE 23. Side-by-side comparison of structural imaging modalities: CT and MRI.

Figure 23 is a comparison of images available with CT versus MRI.

The sensitivity of head CT versus MRI of the brain in the same patient is demonstrated here in a patient

who presented with memory loss. Head CT scan at leftshows a large area of decreased densityconsistent with edema. It is difficult to ascertain whether there is an underlying mass or what its shapemight be. The image on the rightis from a brain MRI (T2 image) and also demonstrates an area ofincreased intensity of about the same shape as the CT abnormality. The patient was found to be HIVpositive, and a subsequent brain biopsy demonstrated that the mass was a B-cell lymphoma.

Source. Images courtesy of Paul E. Schulz, MD, Department of Neurology, Baylor College of Medicine, Houston, Texas.


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The American Psychiatric Publishing Textbook of Psychiatry, Fifth Edition. Edited by Hales RE, Yudofsky SC,Gabbard GO. 2008 American Psychiatric Publishing, Inc. All rights reserved. www.appi.org 36

TABLE 215.

Indications for

computed

tomography (CT),

prior to or instead of

magnetic resonance

imaging (MRI)

Although evidence is limited, structural neuroimaging appears to be indicated for the following clinical

situations for psychiatric patients: new or unexplained focal neurological signs, cognitive changes or

impairment, new-onset psychosis, or prior to the initiation of electroconvulsive therapy. A CT is

valuable when evaluating for suspected hemorrhage or skull fracture or when MRI is contraindicated

(e.g., metal implants) (Table 215).

Source. Adapted from J Levine lectureStructural Neuroimaging in Psychiatry,

given as part of the Neuroimaging in

Psychiatry lecture series, Department of

Psychiatry, Baylor College of Medicine,

March 2006.


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FIGURE 24. Diffusion tensor

imaging (DTI).

DTI, a fairly new imaging technique, is the

subject of intense research in psychiatric and

neurological disorders, including dementias and

cognitive disorders, schizophrenia, mood

disorders, substance use disorders, and brain

injury. Figures 24 and 25 illustrate the whitematter tracts that can be visualized with DTI in

various disorders.

A, Fractional anisotropy color map derived from DTI inthe sagittal plane. Redindicates white matter fibers

coursing in a right-left direction, blue indicates fibersrunning in a superior-inferior direction, and green reflectsfibers oriented in an anterior-posterior direction. B, Fibertracking using DTI of the total corpus callosum overlaidon aT1-weighted inversion recovery image from thesame brain.

Source. Images courtesy of Elisabeth A. Wilde, PhD, Department of Physical

Medicine and Rehabilitation, Baylor College of Medicine, Houston, Texas.


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FIGURE 25. Diffusion

tensor imaging (DTI) in

traumatic brain injury

and bipolar disorder.

Fiber tracking of the corpus callosum in A, a 16-year-old male patient who sustained severe traumatic brain injury andB, an uninjured young man of the same age. The arrowindicates the absence of fibers emanating from the posterior

body of the corpus callosum. Note also the reduced length and number of fibers emanating from other aspects of thecorpus callosum body, likely resulting from injury to the white matter in this area. The mean fractional anisotropy of the

fibers in this system was significantly reduced. In addition to quantitative measures of anisotropy, DTI can be used toexamine aberrant fiber patterns such as that demonstrated in a 55-year-old female bipolar patient (C) as compared withthe expected pattern demonstrated in a woman of comparable age without history of illness (D). Interestingly, thepatient had no significant abnormalities evident on conventional magnetic resonance imaging.

Source. Images courtesy of Elisabeth A. Wilde, PhD, Department of Physical Medicine and Rehabilitation, Baylor College of Medicine, Houston, Texas.


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TABLE 216.

Comparison of SPECT,

PET, and fMRI

SPECT is more widely available than other functional imaging modalities, less expensive, and

technically easier than PET imaging. Because PET tracers have much shorter half-lives than those of

SPECT tracers, they require an on-site cyclotron and radiopharmaceutical laboratory for compounding

immediately prior to each study. In comparison, SPECT tracers are stable for 46 hours after

preparation. Thus, although temporal and spatial resolution is generally superior with PET, it is used

less often for clinical reasons due to practical considerations of tracer acquisition, insurancereimbursement, and cost. Both imaging modalities provide only limited visualization of anatomic

structures; thus, they often require structural MRI to be superimposed on the functional scan.

Table 216 provides a comparison of SPECT, PET, and functional MRI modalities.


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TABLE 216. (enlarged)


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FIGURE 26. Side-by-side comparison of structural and functional neuroimaging:

magnetic resonance imaging (MRI) and positron emission tomography (PET).

Increasingly, structural and functional imaging are used together in the evaluation of neuropsychiatric

and neurological disorders. Figure 26 provides a comparison of structural versus functional

neuroimaging modalities.

Axial image of brain MRI (fluid attenuated inversion recovery images [FLAIR] sequence) and corresponding PETscan of a patient with Alzheimers disease. The MRI image on the leftshows prominent atrophic change in theposterior regions of the brain, consistent with striking reduction of metabolic activity in the posterior parietal lobeson PET imaging.

Source. Image courtesy of Ziad Nahas, MD, MSCR, Department of Psychiatry, Medical College of South Carolina, Charleston, South Carolina.


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FIGURE 27. Side-by-side comparison

of single photon

emission computed

tomography

(SPECT) versus

positron emission

tomography (PET).

Functional imaging techniques such as SPECT and PET are now being used in several clinical

situations, including the evaluation of dementia, presurgical evaluation of medically refractory

seizures, vascular disease to localize compromised vascular reserve, and brain injury. Figure 27

compares SPECT and PET images from patients with mild cognitive impairment.

SPECT(top row) and PET images from two patients with clinically similar degrees of mild cognitive impairment. ThePET scan demonstrates parietal changes, suggesting that this patient is at greater risk of developing Alzheimersdisease. The PET scan also demonstrates much better resolution than the SPECT scan.

Source. Images courtesy of Paul E. Schulz, MD, Department of Neurology, Baylor College of Medicine, Houston, Texas.


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FIGURE 28. Structural magnetic resonance

imaging (MRI) and positron emission

tomography (PET) imaging of a healthy

control subject and a patient with traumatic

brain injury.

Studies have found SPECT to be more sensitive than CT or MRI in the diagnosis of traumatic brain

injury. Structural neuroimaging modalities can detect serious head injuries but often do not detect mild

traumatic brain injuries. Patients with mild traumatic brain injuries often complain of persistent

neuropsychiatric symptoms despite having normal CT or MRI scans. Because of its increased

sensitivity, SPECT may show regional cerebral blood flow hypoperfusion not visible on CT or MRI.

Figures 28, 29, and 210 illustrate the uses of neuroimaging in brain-injured patients.

Coronal slices (MRI) and three-dimensional reconstruction ofthe cortical surface (pink) and hippocampi (yellow) of atypically developing adolescent male (left) and an adolescentmale with traumatic brain injury (right). Note the significantcortical and hippocampal atrophy in the patient as comparedwith the age-matched control. The top rightimage portraysPET findings overlaid on the MRI. PET reveals significant

bilateral metabolic defects in the patients mesial temporal

areas as indicated by the absence of warm colors. Redrepresents areas of the greatest metabolic activity, followedby orange, yellow, green, blue, and violet.

Source. Images courtesy of Erin Bigler, PhD, University of Utah, Salt Lake City, Utah.


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FIGURE 28. (enlarged)



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FIGURE 29. Structural magnetic resonance imaging (MRI) and positron emission

tomography (PET) imaging of a patient with traumatic brain injury.

Despite the absence of significant findings on structural imaging, PET reveals areas of significanthypometabolism in the left temporal area as indicated by the arrow. Redrepresents areas of the greatestmetabolic activity, followed by orange, yellow, green, blue, and violet. The center image is a fusion of the MRIand PET images.



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FIGURE 210. Single photon emission computed tomography (SPECT), structural

magnetic resonance imaging (MRI), and magnetoencephalography (MEG) imaging of a

patient with traumatic brain injury.

Findings from multiple

neuroimaging modalities in apatient with traumatic braininjury reveal structural andfunctional deficits in the inferiorfrontal and temporal regions,common sites of focal injury inhead trauma. Functional

imaging reveals even moreextensive defects in perfusion

(SPECT, left) and dipoleabnormality (MEG, right) thanthe areas of focal injuryevident on structural MRI(center). The fused image(bottom) displays the results ofthe SPECT and MEG overlaidon the MRI.

Source. Images courtesy of Erin Bigler, PhD,

University of Utah, Salt Lake City, Utah.


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FIGURE 211.

Neuroreceptor

imaging.

fMRI has many advantages compared with other functional imaging techniques in that it provides

superior spatial and temporal resolution, is minimally invasive, and does not involve exposure to

harmful ionizing radiation. It is being used extensively in research to understand the neurocircuitry

involved in various psychiatric disorders. Furthermore, the effects of psychotropic medications are

being studied via fMRI, with the hope of understanding the regional brain effects of acute and chronic

treatment with these medications. Figures 211, 212, and 213 illustrate research uses of fMRI.

Magnetic resonance imaging (top) and co-registered positron emission tomography images (bottom) acquiredfrom 40 to 100 minutes following injection of 14.9 mCi [11C]DASB in a 40-year-old healthy male volunteer.A, B: Sagittal plane close to the midline, showing accumulation of activity in the midbrain, thalamus, and

caudate. This picture also illustrates the low level of activity in the cerebellum. Activity concentration is also

seen in the cortical gray matter (cingulate cortex). C, D: Transaxial plane, illustrating activity concentration inthalamus and striatum. E, F: Transaxial plane at the level of the midbrain. The very high activity concentration isseen at the level of the dorsal raphe. The amygdala is also seen on this plane. G, H: Coronal plane at the levelof the anterior striatum, illustrating the ventrodorsal gradient of SERT in the striatum. This view also showsactivity concentration in cingulate and temporal cortices. I, J: Coronal plane at the level of the postcommissuralstriatum, illustrating activity concentrations in the caudate and putamen, in the thalamus, and in the amygdala.

Source. Images courtesy of Gordon Frankle, MD, Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania.


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FIGURE 211. (enlarged)

Source. Images courtesy of Gordon Frankle, MD, Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania.


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FIGURE 212. Functional magnetic resonance imaging of working memory.

Increased regional blood flow evident in prefrontal cortex while a subject is performing the Sternberg Task (leftimage). Corresponding images in Brainsight Frameless used for stereotactic targeting with transcranial magneticstimulation (right images).

Source. Images courtesy of Ziad Nahas, MD, MSCR, Department of Psychiatry, Medical College of South Carolina, Charleston, South Carolina.


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FIGURE 213. Functional magnetic resonance (fMRI) and transcranial magnetic

stimulation (TMS) as a neuroscience tool.

fMRI interleaved with TMS over left prefrontal

cortex in healthy volunteers illustrating bothlocal and transsynaptic functional connectivity

of corticalsubcortical networks.

Source. Images courtesy of Ziad Nahas, MD, MSCR, Department

of Psychiatry, Medical College of South Carolina, Charleston, South

Carolina.


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TABLE 217. Summary of neuroimaging findings in selected psychiatric disorders

Structural and functional neuroimaging of psychiatric disorders has exploded in recent decades, given

the many new and powerful imaging techniques that are now available. Table 217 summarizes the

structural and functional neuroimaging findings in selected psychiatric disorders that may be of

interest to the psychiatric clinician.

(continued)


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CHAPTER 2 Key Points

Laboratory testing of the psychiatric patient in the past has been utilized

mainly to uncover medical or neurological causes of psychiatric symptoms.

The consensus of studies evaluating the role and value of laboratory testing

is that patients who have psychiatric signs and symptoms but who do not

exhibit other physical complaints or symptoms will benefit from a small

screening battery that includes serum glucose concentration, BUN

concentration, creatinine clearance, and urinalysis. Female patients older

than 50 years will also benefit from a screening TSH test, regardless of the

presence or absence of mood symptoms.

More extensive laboratory screening may be necessary for psychiatric

patients who do have concomitant physical complaints or findings on

physical examination or for patients who are of higher risk, such as elderly

or institutionalized patients or those with low socioeconomic status, self-

neglect, alcohol or drug dependence, or cognitive impairment.

Newer laboratory testing methods such as pharmacogenetic testing andtesting for investigational genetic and biological markers have the potential

to transform and dramatically increase the importance of laboratory testing

in the workup of the psychiatric patient.(continued)


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The American Psychiatric Publishing Textbook of Psychiatry Fifth Edition Edited by Hales RE Yudofsky SCGabbard GO 2008 American Psychiatric Publishing Inc All rights reserved www appi org 54

Imaging may also be helpful when atypical features are present, such as an

older age at onset of psychiatric illness, or when cognitive impairment ispresent.

Neuroimaging does not yet play a diagnostic role for any of the primary

psychiatric disorders, but it is still an integral part of the clinical workup for

psychiatric patients to rule out underlying medical causes of psychiatric

symptoms.

Current neuroimaging methods provide both structural and functional dataabout the brain. Structural imaging techniques such as CT and MRI provide

a fixed image of the brain's anatomy and spatial distribution. Newer

functional neuroimaging techniques such as PET and SPECT provide

information about brain metabolism, blood flow, the presynaptic uptake of

transmitter precursors, neurotransmitter transporter activity, and postsynaptic

receptor activity.

Functional scans should always be interpreted in the context of the

underlying structural images.

CHAPTER 2 Key Points (continued)

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02 Laboratory Testing and Imaging