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Results for “Image Processing, Computer-Assisted”

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PubMed1975

Time-dependent image quality using 99mTc-pyrophosphate.

Technetium-99m-labeled pyrophosphate has proved to be a useful skeletal-imaging agent. In this study, specific areas of the skeleton were imaged at times ranging from 1/2 to 6 1/2 hr after injection of 99mTc-pyrophosphate. Count ratios between abnormal and normal bone with respect to adjacent soft tissue were obtained for selected regions of interest on computer-stored scintillation camera images. The results show that image quality improves most rapidly from 1/2 to 2 hr, but further modest gain in quality does occur on views recorded between 2 and 6 hr. All lesions detected on the later images were also observed on the early ones and the ratios of uptake between abnormal and normal bone from computer-processed scintillation camera images did not change appreciably with time after the 1/2-hr images. Our results confirm the clinical impression that overall image quality is better on views obtained at least 3 hr after injection. Further delays in imaging beyond 3-4 hr after injection probably will not result in any appreciable gain in diagnostic accuracy.

Bone Neoplasms↗

PubMed1992

Enhanced color flow imaging of breast cancer vasculature: continuous wave Doppler and three-dimensional display.

Two methods of potentially improving the detection and assessment of breast cancer vasculature by color flow Doppler ultrasonography were studied. Use of continuous wave (CW) Doppler imaging was one method evaluated by a comparison of system sensitivity to small vessel flow by continuous wave and pulsed Doppler methods. The second technique demonstrated color flow image acquisition and three-dimensional (3D) display. Six breast cancer patients were examined with both a color flow pulsed system and a CW Doppler system employing a hand-held transmitter-receiver pair with crossed-beam patterns. The CW unit consistently revealed more regions of tumor flow and multidirectional flow. Good 3D displays were achieved on larger pulsatile vessels, from images obtained during systole and selected for minimal noise.

Adenocarcinoma↗

PubMedDate not supplied

Introduction to computer systems in diagnostic radiology.

Diagnostic radiology is immensely complex. It involves a consultation process, patient handling to produce images, and advanced technology. Computers have been applied extensively to these processes, and examples are given of some of these applications. Fully integrated computerized radiology systems have been an elusive goal. Integrity of patient data is probably the key to integration. Progress in the field continues.

Appointments and Schedules↗

PubMed1979

[Quantitative sacroiliac joint scintigraphy? (author's transl)].

Methodological aspects and clinical value of digital sacroiliac joint scintigraphy area are described. Preinformation of the observer affects the value of the uptake ratios significantly. A data processing is presented which reduces this effect. Nevertheless there is insufficient discrimination between normal persons and patients with acute inflammation. Routine bone scanning can therefore not be used to exclude "inflammatory changes".

Adult↗

PubMed1977

Scene segmentation techniques for the analysis of routine bone marrow smears from acute lymphoblastic leukemia patients.

Automated analysis of lymphoblast cell morphology is being evaluated as a basis for predicting the response to therapy of patients with acute lymphoblastic leukemia. A new technique of scene segmentation particularly applicable to the "cluttered" images of cells in routine bone marrow smears is described. Morphologic characteristics of lymphoblasts found in bone marrow smears made at time of diagnosis were measured by an automated, interactive image-processing system using the new scene segmentation technique. These characteristics, on a patient by patient basis, are being compared to remission length and survival data to develop and test new prognostic methods.

Autoanalysis↗

PubMed1975

[Postural scintimyelography of the cervical spine (author's transl)].

This study discusses the clinical validity of 101 postural scintimyelograms as a screening method for cervical myelopathy. The RIHSA or Ytterbium isotope-examination are not an extra burden to the patient if the radiopharmacon is introduced into the dural sac following Queckenstedt's test. If there is a normal rise and fall of CSF pressure after bilateral jugular compression and postural scintimyelography is judged normal as well, a cervical subarachnoid obstruction may be excluded. If both examinations yield pathological results an obstructive process in the cervical spinal canal is made certain; and in cases of spondylotic myelopathy a positive contrast myelogrpahy may thus be superfluous. If the results of these two examinations are contradictory then further neuroradiolocal studies are indicated.

Cerebrospinal Fluid↗

PubMed1992

[Documentation of digital dacryocystography using video technique].

Digital dacryocystography is considered the optimal radiodiagnostic method in obstructions of the lacrimal pathways. The examination is carried out by a computer-controlled X-ray unit with a C-arc attached to an image-intensifying TV system. In this way the advantages of this technique and of modern video recording are linked. The bilateral filling process of the contrast medium is recorded and the findings simultaneously recorded on videotape. Consequently, pictures of the dynamic flow are retrievable at any time. This provides good diagnostic documentation and an outstanding basis for any scientific analysis.

Diagnosis, Differential↗

PubMed1977

New approach to interpretation of technetium-99m pyrophosphate scintigraphy in detection of acute myocardial infarction: clinical assessment of diagnostic accuracy.

A modified classification for interpreting technetium-99m pyrophosphate scintigrams defines the 2+ diffuse pattern of tracer uptake as equlvocal rather than positive for acute myocardial infarction. Results of scintigraphy using this classification were compared with results of standard diagnostic tests for myocardial infarction in 235 patients admitted to a coronary care unit with acute chest pain. Of 81 patients with acute transmural infarction by standard clinical, electrocardiographic and serum enzyme criteria, 76 had a positive, 5 an equivocal and none a negative scintigram. Of 18 with acute nontransmural infarction by standard criteria, 7 had a positive, 9 an equivocal and 2 a negative scintigram. This it was uncommon for a patient with acute myocardial infarction, transmural or nontransmural, to have a definitely negative technetium-99m pyrophosphate study. Ten patients had equivocal evidence of infarction by standard criteria. Of the remaining 126 patients with no evidence of acute myocardial infarction by standard criteria, 87 had a negative, 35 an equivocal and 4 a definitely positive scintigram. Thus the definitely positive scintigraphic pattern was relatively highly specific for acute myocardial infarction. If the 2+ pattern had been considered positive, the specificity of the technique would have been greatly decreased. Computer processing strengthened observer certainty of the visual impression but changed the scintigraphic evaluation in only eight cases. Thus, use of an equivocal pattern renders technetium-99m pyrophosphate imaging both an extremely sensitive and specific method for detecting acute myocardial infarction.

Acute Disease↗

PubMed1978

Image processing in pathology.

The present study is an effort to ally biopsies to well defined groups of diseases by means of automatic analysis of liver cell nuclei. The results obtained should support the morphologic differential diagnosis of liver diseases. A total of 78 liver biopsies from patients with obstructive jaundice, chronic hepatitis, acute viral hepatitis or with alcoholic liver injury were investigated. Performing automatic analysis of the microscopic pictures 95% of the equatorial sectioned liver cell nuclei are correctly recognized.

Cell Nucleus↗

PubMed1976

Minicomputer enhancement of scintillation camera images using fast Fourier transform techniques.

Minicomputer methods were developed to enhance lesions in scintillation camera images. This study was directed towards improving the diagnostic quality of liver images. A PDP-12 digital computer was interfaced to a Pho/Gamma HP III scintillation camera and programmed to carry out two-dimensional frequency-domain analysis and processing as an on-line operation. A two-dimensional frequency spectrum is produced. An interactive program allows the operator to construct graphically a frequency-domain filter and apply it to the data matrix. The filter is optimized using the image of a known phantom and then applied unchanged to the clincial liver image. An inverse Fourier transform produces an enhances image in the spatial domain. Significant enhancement of both phantom and liver images has been obtained.

Diagnosis, Computer-Assisted↗

PubMed1975

Scintillation camera studies of isotope flow in arteriovenous malformations.

A significant proportion of arteriovenous malformations are still undetected on conventional brain scans. Dynamic scintillation camera studies have shown a pronounced and rapid isotope accumulation in these structures. By means of data processed flow studies, one can distinctly select the inflow phase etc., display TV pictures in optimal phase, and make quantitative comparisons. Thereby, one can obtain a very probable diagnosis, even when the AVM is small or has the characteristics of a fistula which is not seen on routine scans. As the method is simple and not time consuming, it is well suited for clinical screening.

Aged↗

PubMed1977

Experimental infarct sizing using computer processing and a three-dimensional model.

A method for noninvasive sizing of myocardial infarction, in which data from technetium-99m stannous pyrophosphate scintigrams and a three-dimensional model were used, was tested on experimental, acute anterior infarcts in dogs. The results indicate that the method does size experimental anterior infarcts accurately, but further testing will be necessary to assess the capabilities of the technique for sizing other types of infarcts.

Animals↗

PubMed1992

A discussion of two wavefront aberration correction procedures.

This review paper discusses the basic properties of two adaptive signal processing procedures for dealing with weak scattering in a phased array transducer system. A fundamental improvement in the lateral resolution of ultrasonic echo scanners will result if the weight vector of a large phased array transducer can be modified to account for distortion in the propagation medium. Lateral resolution in most tissue is limited to a few mm by wavefront-distortion-induced sound-speed variations. One important wavefront-distortion source is scattering from local speed variations within large and reasonably homogeneous tissue beds such as the liver. Scattering disperses some energy from the beam and perturbs the wavefront, thereby distorting the image and limiting the resolution to the scale of the distortion. Often, such scattering is weak, meaning that most of the energy in the beam is unscattered. The total field at the receiving transducer is the vector sum of the unscattered and scattered fields. In weak scattering the unscattered field is dominant and the resultant field can be treated as the unscattered field plus a perturbation. The net effect is primarily a distorted phasefront, while the amplitude or modulus of the wavefront remains reasonably intact. Refraction and strong scattering effect the wavefront more severely and are less responsive to these algorithms.

Algorithms↗

PubMed1977

An automated method of differential red blood cell classification with application to the diagnosis of anemia.

A method of automated red cell analysis suitable for the rapid classification of large numbers of red cells from individual blood specimens has been developed, and preliminarily tested on normal bloods and clinically proven cases of anemias and red cell disorders. According to this method digital image processing techniques provide several features relating to shape and internal central pallor configurations of red cells. These features are used with a fully automated decision logic to rapidly provide a quantitative "red cell differential" analysis, a report of the percentage subpopulations of recognized categories of red cells. For each subpopulation, measurements of mean cell area, mean cell hemoglobin content and mean cell hemoglobin density are provided. The nine types of red cell disorders studied with this method were: (a) iron deficiency anemia, (b) the anemia of chronic disease, (c) beta-thalassemia trait, (d) sickle cell anemia, (e) hemoglobin C disease, (f) intravascular hemolysis, (g) hereditary elliptocytosis, (h) hereditary spherocytosis, and (i) megaloblastic anemia due to folic acid deficiency. Preliminary indications are that the red cell differential is useful in distinguishing between these conditions.

Anemia↗

PubMedDate not supplied

Event-related potentials in a guessing task: the gleam in the eye effect.

Event-related potentials (ERPs) were recorded from a single subject performing a forced-choice guessing task. On each trial, ERPs were elicited by four, sequential, graphic images; 2 1/2 seconds after the last stimulus was delivered, the subject guessed which of the four images was experimentally (randomly) designated as the target. P200 had greater amplitude over the posterior scalp for stimuli which were guessed by the subject to be targets than for not-guessed stimuli. The amplitude of the P100, N100, and P300 components was unrelated to the subject's guess. A positive displacement evident in the waveforms from about 150-500 ms post-stimulus onset suggested that Slow Wave may have been partially responsible for the observed differences. These results suggest that ERPs may contain predictive information about a subject's subsequent responses in forced-choice guessing tasks. We termed this the "gleam in the eye" effect.

Arousal↗

PubMed1992

Our experience in the diagnosis of intraocular tumours by a B-scan computerized system and angiodynography (Doppler). Preliminary results.

The authors compare the ultrasound diagnostic results of intraocular tumours by A/B-scans (Sonomed B 3000, Sonocare, Sonovision STT-100) with images obtained using computerized B-scan (Sonocare, Sonovision STT-100, Acoustic Tissue Typing ATT) and angiodynopgraphy systems (Quantum Philips). The Sonovision uses a computerized ultrasound spectrum analysis to assess the probability that a given lesion is a certain tumour, rather than another. The ATT system provides diagnostic probability for type B and type E melanoma, for haemangioma and metastatic carcinoma. The Quantum ultrasound equipment was developed for studying the heart and the major blood vessels. It is a colour Doppler that simplifies the Doppler technique, allowing it to study small anatomical parts such as tumour-like lesions of the eye. The Doppler technique ascertains the presence and the velocity of blood flow in the tumours. In presenting the preliminary results with the new techniques the authors are aware that the ATT system is not designed for some of the lesions under study (melanomas after conservative radiotherapy).

Blood Flow Velocity↗

PubMed1992

[Electroencephalographic findings in dementia diseases].

Even if generally the EEG cannot yield specific pointers that are typical for a special pattern of dementia, it is nevertheless meaningful and helpful to perform routine EEG in demented patients. EEG is the functional additional examination that does not place any stress on the patient and is easy to perform at a low cost (1). As a functional diagram the EEG reflects the electrical processes taking place in the cerebral cortex, yielding an excellent image of the cerebral functional state. Assessment of the EEG is done in accordance with internationally standardised criteria. Particular attention is directed at a slowing-down of the background activity, the occurrence and extent of scattered theta and delta waves, their topographical distribution and the development of pathological EEG characteristics during recording (44). Update spectral analysis EEG procedures, i.g. the possibility to calculate power spectra for the individual EEG frequency bands and their topographic distribution, it may be possible in the near future to further improve differentiation between normal and pathological EEG findings. The functional dynamic aspect of the EEG is its particularly strong point in the differential diagnostic clarification of dementia patterns. By repeated EEG recordings, i.e. by close follow-up, and by relating the electrophysiological findings to the clinical pattern, reliable pointers are obtained for the extent of the activity of the process underlying the dementia pattern. EEG is predestined like no other method to enable early detection of rapid changes in cerebral function thanks to its easy operation and unlimited repeatability. The occurrence of parenrhythmic theta and delta waves in the EEG reflects in a special manner the acuity of an organic basic process. In this way EEG enables differentiation between acute and chronic processes of cerebral damage. Over and above this, correlation with the relevant clinical findings makes it possible to differentiate between reversible states of dementia and irreversible defect syndromes and hence also to point to the long-term outcome. Finally, the occurrence of certain patterns of findings or the identification of characteristic wave forms allows essential differential diagnostic pointers and definitions.

Aged↗

PubMed1977

Fully automatic computer-assisted pancreas imaging.

Good pancreas imaging is difficult to achieve even if a computer is applied. The special computer program proposed here was developed to optimize the results and to minimize the operator interaction with the data processing system.

Computers↗