Portal dose images. I: Quantitative treatment plan verification.

The comparison of a predicted portal dose image, calculated during treatment planning, with the measured image obtained during treatment is proposed as an approach to verify the correct implementation of a patient treatment plan. The comparison inherently verifies both the geometric alignment and the dose delivered. Feasibility studies were conducted with 60Co irradiation of a modular plastic phantom, an anthropomorphic phantom and a patient with lung cancer.

Cortical asymmetries in frontal lobes of rhesus monkeys (Macaca mulatta).

Cortical sulci were digitized and their lengths determined with 3-dimensional computer technology on 335 endocranial casts from rhesus monkeys with known maternal genealogies, ages at death, and sex. Non-metric data were also collected from 403 endocasts. Frontal lobes were directionally asymmetrical with lengths of the left central, right rectus (principal), and right lateral orbital sulci significantly longer.

Three-dimensional magnetic resonance imaging.

Three-dimensional surface reconstruction images of the heart and great vessels can be produced from contiguous sequences of ECG-triggered MR scans in patients with congenital heart disease. The methods allow separation of the epi- and endocardial surfaces and definition of the enclosed blood volumes on a slice-by-slice basis. Surface reconstruction images have value in communicating the results of MR examinations to clinicians in cases where cardiac morphology is unusually complex; in depicting intracardiac defects, size, and location; and in aiding the study of pulmonary venous drainage.

Endocranial features of Australopithecus africanus revealed by 2- and 3-D computed tomography.

The earliest hominid from South Africa, Australopithecus africanus, is known from only six specimens in which accurate assessment of endocranial capacity and cranial venous outflow pattern can be obtained. This places a severe limit on a number of hypotheses concerning early hominid evolution, particularly those involving brain-body size relationships and adaptations of the circulatory system to evolving upright posture. Advances in high-resolution two- and three-dimensional computed tomography (CT) now allow the inclusion of another important specimen to this list, MLD 37/38 from Makapansgat.

Heritability of brain size and surface features in rhesus macaques (Macaca mulatta).

The extent of heritability for overall brain size and regional cortical surface features such as sulcus lengths is important for demonstrating a genetic component to the observed phenotypic differences among individuals and for evaluating the potential for evolutionary change in response to selection. Although the genetics of brain size has been extensively considered, the detailed morphology of the cortical surface has not previously been subjected to genetic analysis. We estimated the heritability of brain size and cortical sulcus lengths using 438 endocranial casts taken from skeletons of rhesus macaques (Macaca mulatta) from the Cayo Santiago population.

Three-dimensional surface reconstructions using a general purpose image processing system.

A general purpose two-dimensional (2-D) image processing software system was used to produce high quality three-dimensional (3-D) surface reconstructions from serial sections such as CT scan slices. Depth-encoded 3-D surface images, gradient-shaded 3-D surface images, and weighted sums of these two images were computed. Images that simulate transmission radiographs ("volumetric" views) were created from the same slice data.

Volumetric 3-D imaging of computerized tomography scans.

Contiguous transaxial high resolution CT scans of more than 100 patients with craniofacial deformities and orthopedic disorders were obtained. The CT scan examinations were used diagnostically in determining the need for surgery and for planning therapy. The serial section data was reconstructed in a three-dimensional form with surface and transparent volumetric computer graphics processing techniques.

Heritability and association of cortical petalias in rhesus macaques (Macaca mulatta).

Frontal and occipital petalias, the anterior or posterior protrusions of a cerebral lobe on one side or the other, are among the most striking anatomical asymmetries in human brains. Our previous studies of rhesus macaques revealed a relatively high frequency of right frontal petalias, whereas occipital petalias were seen less often and were equally common on right and left sides. In the present study, we test the hypothesis that variation in frontal and occipital lobular morphology is, in part, genetically based, and that frontal and occipital petalias are associated with one another.

Craniosynostosis: image quality, confidence, and correctness in diagnosis.

The authors used the diagnosis of craniosynostosis to compare subjective evaluation of image quality with objective diagnostic utility. They studied in detail the responses of one observer, who read plain radiographs, computed tomographic (CT) scans, and three-dimensional reconstructions of CT scans (obtained with three different methods) for 82 patients with this diagnosis. The observer rated image quality and certainty in diagnosis made from each image.

Craniosynostosis: diagnostic value of three-dimensional CT reconstruction.

Three-dimensional computed tomography (CT) has an important role in determining the presence and extent of congenital and acquired craniofacial deformities. The authors compared the sensitivity and specificity of three-dimensional CT in the detection and characterization of craniosynostosis with that of planar CT and skull radiography. Eighty-two patients with isolated and syndromal synostoses were imaged with CT and three-dimensional CT, and 42 with skull radiography.

Endocranial suture closure in rhesus macaques (Macaca mulatta).

Endocasts from skulls of 330 rhesus monkeys (Macaca mulatta) of known age are scored for closure of nine bilateral and three unilateral sutures or segments of sutures. A variety of tests reveals a strong relationship between age and stages of suture closure, although increasingly broad confidence intervals prevent sutures from being very useful for precisely aging older macaques. The order in which endosutures begin to close, as well as that in which closure is finally achieved, is determined for macaques, and these sequences compared to those for endosutures of humans (Todd and Lyon, 1924).

Facial musculoskeletal asymmetry in hemifacial microsomia.

Computer-assisted medical imaging--transaxial computed tomography (CT) scans and three-dimensional surface reconstructions--was used to study the muscles of mastication and their osseous origins and insertions in 24 patients with untreated unilateral hemifacial microsomia (HFM). The relationship between the volume of a muscle of mastication and the shape and size of its origin and insertion in such patients varies widely. Comparison of mean volumes of specific muscles documents a statistically significant decrease among patients who have moderate to marked mandibular dysmorphology as compared with those with minimally dysmorphic mandibles.

Tetralogy of Fallot: MR findings.

Surgical treatment of patients with tetralogy of Fallot requires accurate definition of all anatomic structures, particularly the central pulmonary arteries. Magnetic resonance (MR) images of 22 patients with tetralogy of Fallot were studied to assess their usefulness in providing information regarding the spectrum of anatomic abnormalities in this condition. MR findings were compared with information obtained at catheterization (in 16 patients) and at surgery (in nine patients), both of which were performed within 3 months of MR imaging.

Three-dimensional magnetic resonance imaging of the heart.

Three-dimensional surface images of the human heart may be produced from magnetic resonance imaging. These examinations are used in the evaluation of congenital heart disease for preoperative planning and postoperative evaluation. Computer graphics software has been adapted to produce three-dimensional images of the beating heart from contiguous two-dimensional serial EKG-triggered magnetic resonance image data sets.

Three-dimensional surface imaging from CT scans for the study of craniofacial dysmorphology.

Computer-assisted medical imaging technologies provide new tools for the study of congenital craniofacial deformities. Three-dimensional surface reconstructions have been developed to simplify the interpretation and improve the utility of CT scans of the head. While 3-D reconstructions initially were applied to assist clinical management of craniofacial deformities, these images now are finding utility in the study of unique anomalies, the definition of group characteristics for dysmorphic heads, the differentiation of similar phenotypes, and the documentation of the effects of cranial surgery on craniofacial growth.

Three-dimensional surface reconstruction software system for IBM personal computers.

Surface and volumetric three-dimensional imaging methods have found application in fields as diverse as diagnostic medical imaging and paleontological research. The acquisition, modeling, classification, and computer graphics rendering of discrete image volumes will be introduced. Applications in diagnosis (craniofacial, orthopedic, cardiovascular, and others) as well as reconstruction methods for generic serial sections will be described.

Imaging workstations for computer-aided primatology: promises and pitfalls.

In this paper, the application of biomedical imaging workstations to primatology will be explained and evaluated. The technological basis, computer hardware and software aspects, and the various uses of several types of workstations will all be discussed. The types of workstations include: (1) Simple - these display-only workstations, which function as electronic light boxes, have applications as terminals to picture archiving and communication (PAC) systems.

Preoperative three-dimensional reconstruction of the heart and great vessels in patients with congenital heart disease. Technique and initial results.

Magnetic resonance images have been obtained preoperatively in six patients with congenital heart disease. Contiguous sequences of electrocardiogram-triggered spin-echo images have been reconstructed in three-dimensional form to define the size and anatomic relationships to the great vessels and internal cardiac structures. Findings of magnetic resonance imaging were corroborated by angiographic and sector-scan echocardiographic studies and at operation.

Three-dimensional magnetic resonance imaging of congenital heart disease.

Three-dimensional surface reconstruction images of the heart and great vessels have been produced from contiguous sequences of EKG-triggered MRI scans in more than 35 patients with congenital heart disease and 5 normal subjects. The scan data was semiautomatically processed to separate the epi- and endocardial surfaces and to define the outlines of the enclosed blood volumes on a slice by slice basis. Surface reconstruction images aid communication with clinicians, establish the size and location of intracardiac defects, and image the pulmonary venous drainage.

Three-dimensional measurement accuracy of skull surface landmarks.

Craniometric measurements from a three-dimensional (3-D) digitizing system were compared with those from sliding and spreading calipers. The 3-D system consisted of a 3-Space Digitizer, Macintosh Plus computer, and Unigraphics CAD/CAM system. Twenty-nine standard measurements were made and repeated on two normal and three deformed skulls.