Search

Assessing variation in animal coloration is difficult, as animals differ in their visual system properties. This has led some to propose that human vision can never be used to evaluate coloration, yet many studies have a long history of relying on human vision. To reconcile these views, we compared the reflectance spectra of preserved avian plumage elements with two measures that are human biased: RGB values from digital photographs and the corresponding reflectance spectra from a field guide. We measured 73 plumage elements across 14 bird species. The field guide reflectance spectra were drastically different from that of the actual birds, particularly for blue elements. However, principal component analyses on all three data sets indicated remarkably similar data structure. We conclude that human vision can detect much of the variation in coloration in the visible range, providing fodder for subsequent studies in ecology, evolution, behavior, and visual ecology.

Aims: Chronic diseases impose a substantial healthcare burden. This study sought to evaluate the clinical and economic impact of new disease management (DM) programs, targeting four major chronic d...

Experience with 81 gas computed tomography (CT) cisternography procedures in 79 patients in searching for acoustic neuroma is reported. Twenty-one tumors, four exclusively intracanalicular, were demonstrated after standard contrast-enhanced CT was negative. Fifty-five examinations were negative; four were inconclusive. The high resolution scanner with digital localization and reconstruction zoom capability greatly improved image detail. In nine of the 12 normal patients examined with it, the intracanalicular bundle was demonstrated. Substitution of carbon dioxide for air greatly reduced the morbidity of acute post-spinal tap headache. The procedure takes 30--45 min and can be performed on an outpatient basis. It is recommended as the procedure of choice when standard CT is negative in subjects clinically suspected of having acoustic neuroma.

The normal gross and computed tomographic (CT) anatomy of the infrahyoid neck is reviewed. Special emphasis is given to the location of major lymph node chains. Key anatomical levels in the neck are identified, enabling the interpreter of CT scans to place any lesion accurately in space.

Anatomical relationships of temporal bone structures are demonstrated by thin section edge detection computed tomography. Many otic structures are best appreciated in axial view, but reorientation to anatomy as seen in this plane is needed for optimal diagnosis. A level by level review of key structure is presented toward this end. The limitations and advantages of computed tomography are discussed.

We report on the appearance of parathyroid, thyroid, and cervical thymic cysts on computed tomography (CT) scans. The differential diagnostic considerations include thyroglossal and branchial cleft cysts, cystic hygromas, primary and metastatic tumors, dermoids, teratomas, choristomas, tracheoesophageal and cervical bronchogenic cysts, as well as cystic neuromas, abscesses, and lipomas. Most cannot be differentiated using CT alone and require clinical observations, laboratory testing, and surgical and histologic findings for definitive diagnosis. Our experience with these rare lesions is reported, and the differential diagnoses are discussed.

Previously it has been very difficult or impossible for radiologists to delineate accurately the size and extent of glomus tympanicum tumors. By utilizing axial transverse and coronal computed tomography detailed enlargement techniques we have been able to accurately demonstrate four such lesions. We believe that this mode of investigation is now the method of choice for glomus tympanicum tumors.

A retrospective analysis of surgically proved cases of thyroglossal duct cysts was performed in an attempt to determine the characteristics of these lesions using computed tomography (CT). We evaluated 12 preoperative cases and two cases with postoperative complications. Ten patients with lesions that could be confused either clinically or radiographically with these cysts were also evaluated to develop a systemized radiologic differential diagnostic approach for the evaluation of anterior triangle neck lesions. CT enables the differentiation of thyroglossal duct cysts from other anterior triangle lesions based on location, CT values, and alterations in the adjacent soft tissues.

Lesions involving the petrous apex are rarely encountered in clinical practice. This directly affects the ability of the otolaryngologist to diagnose and effectively treat these lesions. Greater physician awareness and increased technologic capability are leading to more effective management of pathologic conditions involving this area of the temporal bone.

High-resolution CT scan is used to clearly identify the components of the innominate line. Fourteen patients with abnormal innominate lines are then examined and used to illustrate the three pathological processes affecting the innominate line, namely, destruction, hyperostosis and expansion.

Routine contrast-enhanced CT scans generally cannot exclude the presence of an acoustic neuroma of 1 cm. or less in size (1,2,3). CT — metrizamide cisternography, though excellent in defining a cisternal mass lesion, cannot be visualized intracanalicular unless the acoustic canal is grossly enlarged and therefore cannot exclude the presence of a lesion limited to canal or porus (2). Pantopaque cisternography has so far been the only neuroradiologie examination that can exclude an intracanalicular acoustic neuroma, although the study may be falsely positive in a small percentage of cases (4, 5, 6) and has a potential risk of producing adhesive arachnoiditis (7,8). The presence of pantopaque may also preclude the CT evaluation of the CP angle cistern at a future date.

During our design of a workstation for diagnostic radiology, and having studied other designs being produced either commercially or institutionally, it became evident that a number of questions existed regarding the number and physical arrangement of CT images which a radiologist likes to have during interpretation. We wished to answer the questions about number and physical arrangement, and at the same time, determine how much difference there was concerning these parameters among the subspecialty sections. We approached this problem by using different numbers and arrangements of CT scan images presented to the radiologist on film. This paper will discuss the findings of this study, and explain some of the reasons given by the radiologists for their answers. The implications for workstation designs will also be discussed.

• Computerized tomography has manifest usefulness in the roentgenologic identification of intracranial masses, and acoustic neuromas are no exception. Nonetheless, traditional roentgenographic examinations for the workup of acoustic neuromas should not yet be completely discarded in favor of this new modality. Computerized tomography scanning is an insensitive and unreliable technique for delineating the size and configuration of the internal acoustic canals. With current technology, it will not reliably show neuromas less than 1.5 cm in cross-sectional dimension. Technical artifacts may also contribute to false-negative and though rare to false-positive findings. The false-negative rate will be unacceptably high in the presence of small lesions if this technique is treated as a definitive examination rather than a screening one. Though uncommon, it may also be negative in the presence of relatively large lesions. ( Arch Otolaryngol 103:314-317, 1977)

The computed tomographic (CT) scans of 44 patients who presented with nonthyroid/parathyroid lesions involving the soft tissues of the neck were analyzed. Among these patients, there were 26 with nodal masses, 6 with vascular lesions, 5 with neural lesions, and 8 with disease involving the connective tissues. One patient had both connective-tissue and vascular disease.CT allowed accurate determination of the extent of disease, while certain CT features added specificity to the diagnosis. It is concluded that CT is the procedure of choice in examining patients with neck lesions.

Sonographic images of the vocal cords were obtained in 41 healthy human subjects using a phased array realtime ultrasound scanner. The thyroid cartilage provides the acoustic window for sonographic visualization of the vocal cords. The false vocal cords appear as hyperechoic structures, while the true vocal cords are seen as hypoechoic structures. The symmetry of movement of the vocal cords during respiration becomes apparent on examination in real time. Sonography may prove to be a potentially useful technique for the examination of the vocal cords.

Active caspase-6 (Csp6) and Tau cleaved by Csp6 (TauDeltaCsp6) are abundant in neuritic plaques (NPs), neuropil threads (NPTs), and neurofibrillary tangles (NFTs) in end-stage Alzheimer's disease (AD) (Guo H, Albrecht S, Bourdeau M, Petzke T, Bergeron C, LeBlanc AC: Active caspase-6 and caspase-6 cleaved Tau in neuropil threads, neuritic plaques and neurofibrillary tangles of Alzheimer's disease. Am J Pathol 2004, 165:523-531). The goal of this study was to determine whether active Csp6 is present in young and aged noncognitively impaired (NCI); aged mild cognitively impaired (MCI); and aged mild, moderate, severe, and very severe AD individuals. Csp6 activity was assessed with anti-p20Csp6 and TauDeltaCsp6 immunoreactivity. Active Csp6 is present in NFTs, NPTs, and NPs at all stages of AD. Active Csp6 is present in NFTs of all MCI cases and present in NPTs and NPs of some MCI cases. Active Csp6 is present in NFTs and NPTs of all NCI cases but is absent in younger cases. The level of TauDeltaCsp6-positive NFTs and NPTs correlates inversely with global cognitive scores in NCI individuals. Therefore, Csp6 activity can occur with aging in the absence of AD and is always associated with clinical and pathological features of confirmed AD cases. Given the ability of active Csp6 to increase amyloid-beta peptide production and cleave Tau and several synaptic proteins (LeBlanc AC, Liu H, Goodyer C, Bergeron C, Hammond J: Caspase-6 role in apoptosis of human neurons, amyloidogenesis and Alzheimer's disease. J Biol Chem 1999, 274:23426-23436; Petzke TL, Rousselet E, Goodyer C, LeBlanc AC: Substrates of caspase-6 in human primary neurons: a proteomic study. Program No. 80.9. 2005 Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience. Online), we suggest that active Csp6 could be an early instigator of neuronal dysfunction.