A Palaeozoic shark with osteichthyan-like branchial arches.

The evolution of serially arranged, jointed endoskeletal supports internal to the gills--the visceral branchial arches--represents one of the key events in early jawed vertebrate (gnathostome) history, because it provided the morphological basis for the subsequent evolution of jaws. However, until now little was known about visceral arches in early gnathostomes, and theories about gill arch evolution were driven by information gleaned mostly from both modern cartilaginous (chondrichthyan) and bony (osteichthyan) fishes. New fossil discoveries can profoundly affect our understanding of evolutionary history, by revealing hitherto unseen combinations of primitive and derived characters. Here we describe a 325 million year (Myr)-old Palaeozoic shark-like fossil that represents, to our knowledge, the earliest identified chondrichthyan in which the complete gill skeleton is three-dimensionally preserved in its natural position. Its visceral arch arrangement is remarkably osteichthyan-like, suggesting that this may represent the common ancestral condition for crown gnathostomes. Our findings thus reinterpret the polarity of some arch features of the crown jawed vertebrates and invert the classic hypothesis, in which modern sharks retain the ancestral condition. This study underscores the importance of early chondrichthyans in resolving the evolutionary history of jawed vertebrates.

Histological evaluation of cardiac remodelling in equine athletes.

Approximately 1-2 per 100,000 young athletes die from sudden cardiac death (SCD) and extreme exercise may be associated with myocardial scar and arrhythmias. Racehorses have a high prevalence of atrial fibrillation (AF) and SCD but the presence of myocardial scar and inflammation has not been evaluated. Cardiac tissues from the left (LAA) and right (RAA) atrial appendages, left ventricular anterior (LVAPM) and posterior (LVPPM) papillary muscles, and right side of the interventricular septum (IVS-R) were harvested from racehorses with sudden cardiac death (SCD, n = 16) or other fatal injuries (OFI, n = 17), constituting the athletic group (ATH, n = 33), and compared to sedentary horses (SED, n = 10). Horses in the ATH group had myocyte hypertrophy at all sites; increased fibrosis at all sites other than the LAA; increased fibroblast infiltration but a reduction in the overall extracellular matrix (ECM) volume in the RAA, LVAPM, and IVS-R compared to SED horses. In this horse model, athletic conditioning was associated with myocyte hypertrophy and a reduction in ECM. There was an excess of fibrocyte infiltration and focal fibrosis that was not present in non-athletic horses, raising the possibility of an exercise-induced pro-fibrotic substrate.

A large multicenter outcome study of female genital plastic surgery.

INTRODUCTION: Female Genital Plastic Surgery, a relatively new entry in the field of Cosmetic and Plastic Surgery, has promised sexual enhancement and functional and cosmetic improvement for women. Are the vulvovaginal aesthetic procedures of Labiaplasty, Vaginoplasty/Perineoplasty ("Vaginal Rejuvenation") and Clitoral Hood Reduction effective, and do they deliver on that promise? For what reason do women seek these procedures? What complications are evident, and what effects are noted regarding sexual function for women and their partners? Who should be performing these procedures, what training should they have, and what are the ethical considerations? AIM: This study was designed to produce objective, utilizable outcome data regarding FGPS. MAIN OUTCOME MEASURES: 1) Reasons for considering surgery from both patient's and physician's perspective; 2) Pre-operative sexual functioning per procedure; 3) Overall patient satisfaction per procedure; 4) Effect of procedure on patient's sexual enjoyment, per procedure; 5) Patient's perception of effect on her partner's sexual enjoyment, per procedure; 6) Complications. METHODS: This cross-sectional study, including 258 women and encompassing 341 separate procedures, comes from a group of twelve gynecologists, gynecologic urologists and plastic surgeons from ten centers in eight states nationwide. 104 labiaplasties, 24 clitoral hood reductions, 49 combined labiaplasty/clitoral hood reductions, 47 vaginoplasties and/or perineoplasties, and 34 combined labiaplasty and/or reduction of the clitoral hood plus vaginoplasty/perineoplasty procedures were studied retrospectively, analyzing both patient's and physician's perception of surgical rationale, pre-operative sexual function and several outcome criteria. RESULTS: Combining the three groups, 91.6% of patients were satisfied with the results of their surgery after a 6-42 month follow-up. Significant subjective enhancement in sexual functioning for both women and their sexual partners was noted (p = 0.0078), especially in patients undergoing vaginal tightening/perineal support procedures. Complications were acceptable and not of major consequence. CONCLUSIONS: While emphasizing that these female genital plastic procedures are not performed to correct "abnormalities," as there is a wide range of normality in the external and internal female genitalia, both parous and nulliparous, many women chose to modify their vulvas and vaginas. From the results of this large study pooling data from a diverse group of experienced genital plastic surgeons, outcome in both general and sexual satisfaction appear excellent.

Anatomy and evolution of the first Coleoidea in the Carboniferous.

Coleoidea (squids and octopuses) comprise all crown group cephalopods except the Nautilida. Coleoids are characterized by internal shell (endocochleate), ink sac and arm hooks, while nautilids lack an ink sac, arm hooks, suckers, and have an external conch (ectocochleate). Differentiating between straight conical conchs (orthocones) of Palaeozoic Coleoidea and other ectocochleates is only possible when rostrum (shell covering the chambered phragmocone) and body chamber are preserved. Here, we provide information on how this internalization might have evolved. We re-examined one of the oldest coleoids, Gordoniconus beargulchensis from the Early Carboniferous of the Bear Gulch Fossil-Lagerstätte (Montana) by synchrotron, various lights and Reflectance Transformation Imaging (RTI). This revealed previously unappreciated anatomical details, on which we base evolutionary scenarios of how the internalization and other evolutionary steps in early coleoid evolution proceeded. We suggest that conch internalization happened rather suddenly including early growth stages while the ink sac evolved slightly later.

Depression of systolic and diastolic myocardial reserve during atrial pacing tachycardia in patients with dilated cardiomyopathy.

Previous reports have shown that increases in heart rate may result in enhanced left ventricular (LV) systolic and diastolic performance. To assess whether this phenomenon occurs in the presence of depressed LV function, the effects of pacing on LV pressure and volume were compared in seven patients with dilated cardiomyopathy (LV ejection fraction 0.19 +/- 0.11) and six patients with no or minimal coronary artery disease (LV ejection fraction 0.69 +/- 0.11). Patients with normal LV function demonstrated significant increases in LV peak-positive dP/dt, LV end-systolic pressure-volume ratio, LV peak filling rate, and a progressive leftward and downward shift of their pressure-volume diagrams, compatible with increased contractility and distensibility in response to pacing tachycardia. There was no change in LV peak-negative dP/dt or tau. Patients with dilated cardiomyopathy, in contrast, demonstrated no increase in either LV peak-positive dP/dt or the end-systolic pressure-volume ratio, and absence of a progressive leftward shift of their pressure-volume diagrams. Moreover, cardiomyopathy patients demonstrated no increase in LV peak-negative dP/dt or LV peak filling rate and a blunted downward shift of the diastolic limb of their pressure-volume diagrams. Tau, as determined from a derivative method, became abbreviated although never reaching control values. We conclude that patients with dilated cardiomyopathy may demonstrate little or no significant enhancement in systolic and diastolic function during atrial pacing tachycardia, suggesting a depression of both inotropic and lusitropic reserve.

Time course of left ventricular dilation after myocardial infarction: influence of infarct-related artery and success of coronary thrombolysis.

Dilation of the left ventricle after myocardial infarction is common, occurs rapidly (within 2 weeks of infarction) and may be self-limited. To evaluate the time course of postinfarction left ventricular dilation and to assess the impact of successful coronary thrombolysis, serial radionuclide left ventricular volume analyses were performed in 36 patients undergoing attempted thrombolysis for acute transmural myocardial infarction. All patients underwent cardiac catheterization, coronary angiography and attempted thrombolysis within 7 h of the onset of symptoms. The site of coronary occlusion was the left anterior descending coronary artery in 17 patients, the right coronary artery in 18 and, in 1 patient, occluded bypass grafts to the right and left circumflex coronary arteries. Attempted reperfusion using a thrombolytic agent was successful in 22 individuals, occurring 5 +/- 1 h after the onset of symptoms. Gated radionuclide ventriculography was performed early (mean time 1 day after admission, n = 36), subacutely (mean time 11 days postinfarction, n = 36) and late after infarction (mean time 10.5 months, n = 25), and a geometric technique was used to measure serial left ventricular end-diastolic volume. Left ventricular end-diastolic volume for the entire group increased significantly (p less than 0.01) from 153 +/- 30 ml at baseline to 172 +/- 45 ml (at 11 days) to 220 +/- 63 ml (at 10.5 months). Twenty of 36 patients showed greater than 20% increase in left ventricular end-diastolic volume (dilation) with time. This appeared early in seven patients, occurred remote from infarction in seven others and showed a progressive pattern in six.(ABSTRACT TRUNCATED AT 250 WORDS)

Diastolic function in patients with aortic stenosis: influence of left ventricular load reduction.

Pressure overload hypertrophy of the left ventricle due to aortic stenosis is associated with abnormalities of left ventricular isovolumic relaxation and early diastolic filling. The relative contribution of the hemodynamic load on the left ventricle to the impairment of diastolic function observed in this disorder remains poorly understood. To study this relation, the vasodilator nitroprusside was administered to eight patients with aortic stenosis and normal systolic function. The effect of a short-term reduction in left ventricular preload and afterload on left ventricular isovolumic relaxation and early diastolic filling was assessed by analysis of simultaneous micromanometer left ventricular pressure and radionuclide angiographic volume measurements. At baseline, left ventricular systolic and end-diastolic pressures were markedly elevated, and associated with prolongation of the time constant of left ventricular relaxation and depression of the left ventricular peak filling rate. Infusion of nitroprusside resulted in reduction of left ventricular systolic (204 +/- 31 to 176 +/- 31 mm Hg, p less than 0.05) and end-diastolic (31 +/- 8 to 18 +/- 6 mm Hg, p less than 0.05) pressures, with no associated improvement in time constant of left ventricular pressure decay (T) (68 +/- 25 to 80 +/- 37 ms, p = NS), T 1/2 (34 +/- 8 to 34 +/- 14 ms, p = NS), left ventricular peak filling rate (2.3 +/- 0.5 to 2.3 +/- 0.8 end-diastolic volume/s, p = NS) or time to left ventricular peak filling rate (150 +/- 50 to 144 +/- 37 ms, p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Intracoronary thallium-201 scintigraphy after thrombolytic therapy for acute myocardial infarction compared with 10 and 100 day intravenous thallium-201 scintigraphy.

Thallium-201 imaging has been utilized to estimate myocardial salvage after thrombolytic therapy for acute myocardial infarction. However, results from recent animal studies have suggested that as a result of reactive hyperemia and delayed necrosis, thallium-201 imaging may overestimate myocardial salvage. To determine whether early overestimation of salvage occurs in humans, intracoronary thallium-201 scans 1 hour after thrombolytic therapy were compared with intravenous thallium-201 scans obtained approximately 10 and 100 days after myocardial infarction in 29 patients. In 10 patients with angiographic evidence of coronary reperfusion, immediate improvement in thallium defects and no interim clinical events, there was no change in imaging in the follow-up studies. Of nine patients with coronary reperfusion but no initial improvement of perfusion defects, none showed worsening of defects in the follow-up images. Six of these patients demonstrated subsequent improvement at either 10 or 100 days after infarction. Seven of 10 patients with neither early evidence of reperfusion nor improvement in perfusion defects had improvement of infarct-related perfusion defects, and none showed worsening. In conclusion, serial scanning at 10 and 100 days after infarction in patients with no subsequent clinical events showed no worsening of the perfusion image compared with images obtained in acute studies. Therefore, there is no evidence that thallium-201 imaging performed early in patients with acute myocardial infarction overestimates improvement.

Left ventricular pressure-volume diagrams and end-systolic pressure-volume relations in human beings.

Assessment of left ventricular pressure-volume relations serially in response to altered loading conditions and heart rate has been difficult to achieve with contrast ventriculography. Accordingly, to study changing pressure-volume relations during altered loading and heart rate, left ventricular pressure and radionuclide absolute volume curves (obtained using a counts-based method with attenuation factor corrections) were recorded in 20 patients. Ventricular pressure and radionuclide volume curves were digitized and synchronized to end-diastole, and pressure-volume plots were subsequently constructed from 32 pressure-volume coordinates throughout the cardiac cycle. In all patients, the correlation between radionuclide absolute volumes and angiographic ventricular volumes was r = 0.92. In 10 patients in whom both radionuclide and angiographic pressure-volume diagrams were constructed, the agreement between the two methods was excellent. With this method, end-systolic pressure-volume relations were examined during altered left ventricular loading conditions, pacing-induced incremental increases in heart rate and pacing-induced ischemia. Using pharmacologically induced changes in left ventricular loading conditions, the slope and volume intercept of the end-systolic pressure-volume line could be calculated as a means of assessing basal contractility. During pacing-induced tachycardia, the slope and volume intercept of the end-systolic pressure-volume line could be calculated to quantify the Treppe effect and assess negative inotropic changes secondary to ischemia. This study supports the validity of using serial recordings of left ventricular pressure and radionuclide volumes to assess left ventricular pressure-volume relations, and indicates that this approach may be useful in the analysis of end-systolic pressure-volume relations in patients.

Balloon dilation of mitral stenosis in adult patients: postmortem and percutaneous mitral valvuloplasty studies.

Preliminary reports have documented the utility of percutaneous balloon valvuloplasty of the mitral valve in adult patients with mitral stenosis, but the mechanism of successful valve dilation and the effect of mitral valvuloplasty on cardiac performance have not been studied in detail. Accordingly, mitral valvuloplasty was performed in five postmortem specimens and in 18 adult patients with rheumatic mitral stenosis, using either one (25 mm) or two (18 and 20 mm) dilation balloons. Postmortem balloon dilation resulted in increased valve orifice area in all five postmortem specimens, secondary to separation of fused commissures and fracture of nodular calcium within the mitral leaflets. In no case did balloon dilation result in tearing of valve leaflets, disruption of the mitral ring or liberation of potentially embolic debris. Percutaneous mitral valvuloplasty in 18 patients with severe mitral stenosis (including 9 with a heavily calcified valve) resulted in an increase in cardiac output (4.3 +/- 1.1 to 5.1 +/- 1.5 liters/min, p less than 0.01) and mitral valve area (0.9 +/- 0.2 to 1.6 +/- 0.4 cm2, p less than 0.0001), and a decrease in mean mitral pressure gradient (15 +/- 5 to 9 +/- 4 mm Hg, p less than 0.0001), pulmonary capillary wedge pressure (23 +/- 7 to 18 +/- 7 mm Hg, p less than 0.0001) and mean pulmonary artery pressure (36 +/- 12 to 33 +/- 12 mm Hg, p less than 0.01). Left ventriculography before and after valvuloplasty in 14 of the 18 patients showed a mild (less than or equal to 1+) increase in mitral regurgitation in five patients and no change in the remainder.(ABSTRACT TRUNCATED AT 250 WORDS)

Misplacement of central venous pressure catheters and unilateral pulmonary edema.

Two instances of misplacement of a central venous pressure monitoring catheter into a pulmonary artery are presented. In one case, reported in detail, unilateral pulmonary edema developed during administration of 0.5N saline for the treatment of diabetic acidosis via the misplaced catheter, and it reverted following repositioning of the catheter in the superior vena caca. Experiments were carried out in dogs to explore possible causes of this phenomenon. The results of these experiments suggest that the release of vasoactive substances, stimulation of neural reflexes, or both are the pathophysiological mechanisms responsible for the development of the pulmonary edema.

Syn-vivo bioerosion of Nautilus by endo- and epilithic foraminiferans (New Caledonia and Vanuatu).

A variety of syn-vivo bioerosion traces produced by foraminiferans is recorded in shells of Nautilus sampled near New Caledonia and Vanuatu. These are two types of attachment scars of epilithic foraminiferans and two forms of previously undescribed microborings, a spiral-shaped and a dendritic one, both most likely being the work of endolithic 'naked' foraminiferans. Scanning electron microscopy of epoxy-resin casts of the latter revealed that these traces occur in clusters of up to many dozen individuals and potentially are substrate-specific. The foraminiferan traces are the sole signs of bioerosion in the studied Nautilus conchs, and neither traces of phototrophic nor other chemotrophic microendoliths were found. While the complete absence of photoautotrophic endoliths would be in good accordance with the life habit of Nautilus, which resides in aphotic deep marine environments and seeks shallower waters in the photic zone for feeding only during night-time, the absence of any microbial bioerosion may also be explained by an effective defence provided by the nautilid periostracum. Following this line of reasoning, the recorded foraminiferan bioerosion traces in turn would identify their trace makers as being specialized in their ability to penetrate the periostracum barrier and to bioerode the shell of modern Nautilus.

Cerebral perfusion imaging with iodine 123-labeled amines.

Two amines, N-isopropyl p-iodoamphetamine and N,N,N'-trimethyl-N'-[2-hydroxyl-3-methyl-5-iodobenzyl]-1,3-prop anediamine, have been labeled with iodine 123. The brain uptake of these radioactive tracers is proportional to cerebral blood flow. These tracers are retained in the brain for a sufficiently long time so that imaging can be performed with standard, readily available instrumentation. Transaxial tomography with amines is useful in acute cerebral infarction, in which the x-ray computed tomographic scan may be normal for several days after onset of symptoms while the uptake of radioisotope-labeled amines will be altered immediately after the onset of the stroke. It is also useful in examining patients with cerebral vascular disease and in the preoperative examination of patients with partial epilepsy.

Blinded clinical evaluation of positron emission tomography for diagnosis of probable Alzheimer's disease.

We evaluated the sensitivity and specificity of positron emission tomography for diagnosis of probable Alzheimer's disease under conditions similar to those encountered in the routine clinical practice of nuclear medicine. We obtained tomographic images of regional cerebral blood flow from three groups of subjects: (1) 13 subjects, ages 69 to 84, who had probable Alzheimer's disease diagnosed by validated clinical criteria; (2) 15 subjects, ages 57 to 77, who had Parkinson's disease without dementia; and (3) 11 subjects, ages 65 to 83, who were normal. Three blinded reviewers, who had not previously seen the images, categorized them as normal, bilateral temporoparietal flow defects typical of Alzheimer's disease, or other abnormality. Consensus interpretation demonstrated sensitivity of 0.38 (5/13) and specificity of 0.88 (23/26) for identifying patients with probable Alzheimer's disease. Thus, the criterion of bilateral temporoparietal reduction in cerebral blood flow used in this study did not have sufficient sensitivity to be of clinical value. While other criteria may be developed to improve diagnostic accuracy, clinical utility can be established only by testing for validity in patients with a full spectrum of complicating neurologic and psychiatric conditions for whom diagnosis is uncertain and who are then followed longitudinally to determine clinical outcome or pathologic findings.

Scintigraphy of hepatic hemangiomas: the value of Tc-99m-labeled red blood cells: concise communication.

Fourteen patients with hepatic hemangiomas were evaluated by Tc-99m colloid scintigraphy and Tc-99m RBC angiography, including flow studies and early and delayed static studies. On colloid scintigraphy, the liver appeared enlarged, with single or multiple focal defects. During the flow and early static Tc-99m RBC studies, the lesions showed poor perfusion and were filled only partially or not at all. Delayed Tc-99m RBC studies demonstrated the whole extent of the lesion and all the lesions when multiple hemangiomas were present. A flow study showing decreased perfusion and a late blood-pool study showing increased local blood volume appear characteristic of hemangiomas. Liver biopsy should not be attempted in such cases.

Consensus development for producing diagnostic procedure guidelines: SPECT brain perfusion imaging with exametazime.

UNLABELLED: A method for developing diagnostic practice guidelines is presented in which a team of experts used a semiquantitative scoring system to reach consensus on a standard procedure for SPECT cerebral perfusion imaging. METHODS: An expert panel generated a list of elements that they thought were important for the optimal performance of cerebral perfusion imaging as the first phase of a modified Delphi panel technique. Panel members then scored each statement to indicate the importance of that statement for the performance of cerebral perfusion imaging. The scores were recorded for each statement and the average score, s.d. and variance for each statement were determined for each successive panel round. A total of three panel rounds were conducted. The change in average s.d. between scoring rounds was analyzed for significance using both parametric and nonparametric tests. RESULTS: The average s.d. decreased by 35% from 2.1 to 1.32 between the first and final panel round. This change in average s.d., which indicated enhanced consensus, was significant at p < 0.0001. Following consensus, all statements were grouped into four categories based on average score: critical elements, important elements, less important elements and elements of uncertain importance. This grouping formed the basis for a guideline summary narrative. Results were generated in 3 mo, at low cost and with clear documentation of rationale. CONCLUSION: Through simple adaptations of this methodology, expert panels that develop practice guidelines can replace informal discussion with systematic scoring methods to rate the quality of evidence, generalizability to practice conditions, appropriate indications and strength of recommendations.

Effects of a reduction in crystal thickness on Anger-camera performance.

The performances of two commerical gamma cameras, with crystals 1.3 and 0.6 cm thick, are compared. Phantom studies simulating clinical conditions showed no significant difference in performance at 140 keV. At 68 keV, the thinner crystal gave marginal improvements in camera performance with phantoms simulating clinical conditions. Frequent use with very low-energy emitters, such as Tl-201, would be needed to justify the expense required to refit the 1.3 cm camera with a 0.6 cm crystal.

Radon update: facts concerning environmental radon: levels, mitigation strategies, dosimetry, effects and guidelines. SNM Committee on Radiobiological Effects of Ionizing Radiation.

The risk from environmental radon levels is not higher now than in the past, when residential exposures were not considered to be a significant health hazard. The majority of the radon dose is not from radon itself, but from short-lived alpha-emitting radon daughters, most notably 218Po(T1/2 3 min) and 214Po (T1/2 0.164 msec) along with beta particles from 214Bi (T1/2 19.7 min). Radon gas can penetrate homes from many sources and in various fashions. Measuring radon in homes is simple and relatively inexpensive and may be accomplished in a variety of ways. Although it is not possible to radon-proof a house, it is possible to reduce the level. In high radon areas, if the average level is higher than 4-8 pCi/liter (NCRP recommended level is 8 pCi/liter; EPA recommended level is 4 pCi/liter), appropriate action is advised. The shape of the dose response curves for miners exposed to alpha-emitting particles in the workplace is consistent with current biologic knowledge. It is linear in the low dose range and saturates in the high dose range. No detectable increase in lung cancer frequency is seen in the lowest exposed miners (those with exposures < 120 WLM, the relevant dose interval for most homes). Evidence for a health effect from radon exposure is based on data from animal studies and epidemiologic studies of mines. Extensive radiobiologic data predict a linear dose-response curve in the low dose region due to poor biological repair mechanisms for the high density of ionizing events that alpha particles create. However, no compelling evidence for increased cancer risks has yet been demonstrated from "acceptable" levels (< 4-8 pCi/liter).

Comparison of differences in the hemodynamic response to passive postural stress in healthy subjects greater than 70 years and less than 30 years of age.

To test the hypothesis that age-related increases in arterial pressure alter the cardiovascular response to physiologic stress, 9 healthy elderly volunteers (74 +/- 2 years) and 7 young subjects (27 +/- 3 years) were subjected to a standard 60 degrees upright tilt. Cardiac volumes were measured with patients in the supine position and 5 minutes after they assumed an upright posture using radionuclide ventriculography, while heart rate, blood pressure and forearm cutaneous flow were recorded continuously and simultaneously. Only the expected age-related increase in mean arterial pressure (young subjects, 79 +/- 1 mm Hg; elderly subjects, 99 +/- 3 mm Hg; p less than 0.001) distinguished the 2 groups at baseline. However, during upright tilt, elderly subjects had significant decreases in stroke volume (supine [108 +/- 9 ml] vs upright [78 +/- 9 ml]; p less than 0.01) and cardiac index (supine [3.4 +/- 0.2 liters/min/m2] vs upright [2.8 +/- 0.2 liters/min/m2]; p less than 0.05) because of an inability to reduce end-systolic volume (supine, 44 +/- 6 ml; upright, 51 +/- 7 ml); however, mean arterial pressure was maintained through an increase in peripheral resistance. In contrast, the young relied solely on cardiac adaptations to postural stress by decreasing end-systolic volume (supine, 62 +/- 5 ml; upright, 39 +/- 5 ml; p less than 0.01) and increasing heart rate (57 +/- 2 min-1 to 71 +/- 3 min-1, p less than 0.01), whereby cardiac output and mean arterial pressure were maintained during tilt.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical brain imaging with isopropyl-iodoamphetamine and SPECT.

In recent years, fierce competition has developed between the new high technology specialties of ultrasound, nuclear medicine, computerized transmission tomography, and most recently, nuclear magnetic resonance. Conventional brain scintigraphy, once the most common nuclear medicine procedure, has fallen victim to this rivalry despite the fact that routine scintigraphy remains a good diagnostic test. The agony of this defeat initially caused self-doubt among nuclear medicine physicians, but out of this gloom has emerged a number of radionuclide tests which have the potential to revolutionize how clinical neurology/psychiatry is practiced.