Liver Scintigrams Research Articles

ニューラルネットワークによる肝シンチグラムの解析

Colloid liver scintigraphy has been performed widely for diagnosis of diffuse parenchymal liver disease. Pattern of these disease such as chronic hepatitis or liver cirrhosis is evaluated by size and distortion of the liver, distribution of tracer in the liver, size and activities of tracer in the spleen, visualization of the bone marrow and so on. It is not difficult to read a scintigram which shows typical pattern of normal, chronic hepatitis and liver cirrhosis, but in some cases it is difficult to read normal or chronic hepatitis and chronic hapatitis or liver cirrhosis in visual diagnosis. So we tried to use a neural network to make differential diagnosis accurately.First, five features in colloid liver scintigrams were evaluated visualy. Thses features were left lobe/right lobe length splenomegaly, visualization of the bone marrow, liver deformity, and distribution of tracer in the liver.Analysis of liver scintigrams was carried out by the neural network using these features. True positive ratio in the neural network was as follows. Normal: 92% (23/25) ; Chronic hepatitis: 71% (27/38) ; Liver cirrhosis: 93% (39/42) . The relationship of diffuse parenchymal liver disease and these features also was found by analysis of the inner structure in the neural network. Thus one conclude that the neural network is useful on colloid liver scintigraphy because diffrential diagnosis can be done with 85% in overall true positive ratio, and the method is simple and useful clinically.

Reversible interframe compression of medical images: a comparison of decorrelation methods

The authors investigate whether data representing medical image sequences can be compressed more efficiently by taking into account the temporal correlation between the sequence frames. The standard of comparison is intraframe HINT, the best-known reversible decorrelation method for 2-D images. In interframe decorrelation, a distinction is made between extrapolation- and interpolation-based methods, and methods based on local motion estimation, block motion estimation, and unregistered decorrelation. These distinctions give six classes of interframe decorrelation methods, all of which are described. The methods are evaluated by applying them to sequences of coronary X-ray angiograms, ventricle angiograms, and liver scintigrams, as well as to a (nonmedical) videoconferencing image sequence. For the medical image sequences: (1) interpolation-based methods are superior to extrapolation-based methods; (2) estimation of interframe motion is not advantageous for image compression; (3) interframe compression yields entropies comparable to intraframe HINT at higher computational costs; and (4) two methods, unregistered extrapolation and interpolation, are nonetheless possibly interesting alternatives to intraframe HINT.

Evaluation of digital image enhancement techniques for liver scintigrams

Digital image enhancement techniques were employed in an effort to improve the resolution of Anger camera liver images. The premise employed was that methods which improve lesion detectability in liver phantoms should also do so in actual liver scintigrams. The types of image processing evaluated were: contrast enhancement, finite and infinite impulse response, modulation transfer function correction, homomorphic and median filtering. Observers were used to evaluate each method for its ability to improve lesion detectability using a five category rating system. The localization receiver operating characteristic (LROC) curve was used as the primary rank ordering method. A point system and analysis of variance were used as corroborative methods, incorporating measures of accuracy and consistency of the observers' answers.

Sensitivity, Specificity, and Predictive Accuracy as Measures of Efficacy of Diagnostic Tests

ABSTRACT The proliferation of new tests based on sophisticated technology has given impetus to critical evaluation of the role of clinical decision making. In this presentation selected aspects of ...

Detection and display of defects in medical scintigraphic images

To achieve the evaluation of the lesion detectability of a program implemented by us on a minicomputer system to indicate possible defects on liver scans, we simulated a set of geometrical phantoms with different patterns of cold lesions to obtain LROC curves in different cases. Then, to check its clinical value, the program was applied to 44 liver scintigrams of patients among which 7 occurred to be pathological. These liver scintigrams had been evaluated by 6 clinicians so that a comparison between the program and the clinicians could be performedd on the basis of the corresponding LROC curves. Moreover, once an abnormality had been detected by the program, the abnormality was processed in order to perform a psychovisual evaluation of the image more easily: an adapted local 2-level display of the possible defect was superimposed on the scan to enhance it and to facilitate diagnosis.

Extensive Metastases in Peutz-Jeghers Syndrome

A 27-year-old woman with Peutz-Jeghers syndrome since age 11 years was hospitalized with a sudden onset of weakness of the right extremity, an expressive aphasia, and a three-month history of back pain. Liver and whole-body scintigrams demonstrated multiple metastatic disease; the brain scintigraphic study was compatible with infarction of the left hemisphere. Postmoretem examination two weeks after these studies showed extensive metastases in bone, liver, brain, lung, and left ovary. The source of the metastases was a malignant change from Peutz-Jeghers polyps.

Correlations between Geometrical Parameters Measured on Liver Scintigrams and Clinical Observations

Various geometrical data, resulting from anterior scans, of both normal and pathological livers were classified and analyzed statistically from two points of view: Firstly, a static study resulting from observations on pooled scans. This study showed that the frequency distributions of some geometrical parameters in the liver are essentially normal in character. It equally demonstrated that the dimensions of the parameters depend on the degree of the pathology of the liver. Secondly, a study which was carried out on repeated scans recorded on the same patient. It showed that the relative variations of some geometrical parameters of the liver are a function of its degree of pathology, whatever the types of abnormalities considered. The definition of a variable is suggested, the knowledge of which can help to establish the diagnosis.

Liver scintigraphy in the follow-up of a patient on cytotoxic therapy

A 63-year-old male patient with a small cell bronchial carcinoma on cytotoxic therapy was followed up with the use of liver scintigraphy. In the various scintigrams the remission as well as the late reappearance of the liver metastasis was demonstrated. The abnormalities in the liver scintigrams correlated with the biochemical changes throughout the course.

Positive Liver Scan in Clonorchiasis

To the Editor.— It is well recognized that there are multiple causes of positive radiocolloid liver scintigrams. To this list of causes, I add another— clonorchiasis. Report of a Case.— A 22-year-old man was admitted on Aug 21, 1974, with a chief complaint of sudden onset of right upperquadrant abdominal pain of four days' duration. The pain was sharp and persistent in nature. About one month prior to admission, he had eaten raw freshwater fish called grass carp ( Ctenopharyngodon idellus ). He had eaten uncooked sea fish in the past. The patient was well-developed and moderately nourished, with no evidence of jaundice. Tenderness over the right upperquadrant of the abdomen was noted. Laboratory values included the following: hemoglobin, 14.7 gm/100 ml; hematocrit, 44%; red blood cells, 5.9 m/cu mm, white blood cells, 22,250/cu mm, with 84% eosinophils. Liver function test results were normal except for an increase of alkaline phosphatase (170

Combined pancreas and liver scanning using a double isotope technique.

Abstract Experience has been gained in using the dual radioisotope method routinely to scan the pancreas in over 200 patients. Results are presented for the first 129 patients for both the pancreas scans and the gamma-camera scintigrams taken at the same time. These show that a normal pancreas scan virtually excludes disease of that organ. Three lesions were missed in a total of 38 patients. Abnormal scans showed a variety of presentations with no uptake or reduced uptake being a more common appearance. Space-occupying lesions may be defined, but the poor statistics of the method makes diagnosis difficult. In this selected series abnormal scans were nearly always associated with pancreatic disease or disease elsewhere. Sixty-two scans showed an abnormal appearance. Liver scintigrams were carried out on a gamma-camera before the pancreas examination. Of 52 normal scintigrams 46 were proved to be normal (87 per cent) while six space-occupying lesions were missed. Twenty out of 24 patients (83 per cent) had ...