Toru Matsumoto

Image processing for computer‐aided diagnosis of lung cancer by CT (LSCT)

This paper reports a special-purpose CT for early detection of lung cancer and presents the basic idea. The parallel use of the following two systems is investigated as the diagnosis-support image display method needed in such a system, and a satisfactory result is obtained. n n n n(1) nThe maximum intensity projection (MIP) is applied as a means to realize the two-dimensional projection display from the three-dimensional information composed of 40 slices of lung tissue while retaining the information concerning the pathological shadows. When the simple MIP is applied, there is a large disturbance due to unnecessary organ signals. Consequently, a method is developed in which unnecessary information is deleted by thresholding; n n(2) nThe automatic recognition of candidates for the pathological shadows is applied to each slice. Only the CT image containing a shadow candidate is displayed on CRT, which helps to reduce greatly the number of cross sections to be displayed. In the automatic recognition of the pathological shadow, the quoit filter recently developed by the authors is employed.

Quoit filter-a new filter based on mathematical morphology to extract the isolated shadow, and its application to automatic detection of lung cancer in X-ray CT

We propose a new algorithm named Quoit filter (Q-filter) to extract the isolated but low amplitude shadow located in the background which has extremely high amplitude fluctuation. Q-filter is a kind of mathematical morphology and its formulation is quite simple. This simplicity brings about a unique merit that output from this filter is analytically expressive for the case of analytical input shapes like ball, cone, or rotation of cosine function, which have characteristics of rotation symmetry and monotonic decreasing from the origin. This Q-filter is composed of two sequential operations named Q Trans. and Q Inv. Trans., Q Trans. corresponds to extracting feature parameters like a matched filter from the input image having a nonideal isolated shadow, and Q Inv. Trans. corresponds to restoring isolated images using extracted feature parameters. This filter is applied to detecting the cancer candidate shadow automatically in the CT cross sections of lung areas, aiming to reduce drastically the number of cross sections to be diagnosed by the doctor.

Automatic detection of lung cancers in chest CT images by variable N-Quoit filter

We report the image processing technique for computer-aided diagnosis of the lung cancer screening system by CT (LSCT). LSCT is a mobile-type CT scanner for the mass screening of lung cancer. In this LSCT system, one essential problem is the increase of image information to be diagnosed by a doctor to about 30 slices per patient from 1 X-ray film. To solve this difficult problem, we are trying to reduce the image information drastically to be displayed for the doctor by image processing techniques. We propose a new method named variable new-Quoit filter for the automatic recognition of the pathological shadow candidates. Our computer aided diagnosis (CAD) system can satisfactorily reduce the number of CT cross sections by this method, containing the abnormal shadow candidates.

Automatic Detection of Lung Cancers in Chest CT Images by the Variable N-Quoit Filter

The authors have developed the quoit filter, which is a kind of mathematical morphological filter, for automatic extraction of candidate pathological areas of lung cancer. The method has problems, however, in processing speed or extraction accuracy. To overcome these problems, this paper proposes variable quoit filtering, in which the filter size is adjusted flexibly according to the pathological shadow, and distance transformation with gray-level weight is applied as preprocessing before the main filtering procedure. First, the performance of the method is analyzed using a model, and the effectiveness of the proposed method is shown. Then, trial applications to images of 82 actual cases (including 21 cancer areas) show that all of the cancer areas were correctly extracted. Compared to the conventional algorithm, the processing time is reduced to less than 1/20.

A dynamic study of rectally absorbed ammonia in liver cirrhosis using [13N] ammonia and a positron camera

Abstract[13N] Ammonia produced by the cyclotron was instilled intrarectally in patients with cirrhosis and other liver diseases to study the turnover of rectally absorbed [13N] ammonia. A positron camera connected to an on-line computer system was used for the measurement of sequential changes of13N activity in blood and for coincidence positron imaging of the liver and heart.13N activity over the head was also recorded. Chromatographic analysis of13N-labeled substances in blood was carried out using a Dowex 50Wx8 column at varying times after the administration. In the control, [13N] ammonia was absorbed quickly and visualized the liver, whereas in patients with cirrhosis, the lungs and heart were first visualized, and13N activity over the head was also higher. It was suggested that a large proportion of absorbed [13N] ammonia bypassed hepatocytes and reached peripheral tissues in cirrhosis. The heart/liver ratio of13N and13N over the head were correlated with various indices of portal hypertension. The relative proportion of nonammonia13N metabolites in blood was lower at 5 and 15 min after administration in cirrhosis, suggesting a reduced capacity of the liver to remove and metabolize ammonia.

Network based CAD system for lung cancer screening by X-ray CT

This paper presents a network based CAD system for lung cancer screening by LSCT based on our proposed system. The system is server client style, and running on PC (Personal Computer). The system consists of two parts, automatic processing part and image based diagnosis part. The two parts are connected with network. The data of CT images are processed by automatic processing part in server, and have data transferring with client. The client of image based diagnosis part is constructed for radiologists. Radiologists operate the client to make screening works, and give final clinical records.

A Retrospective Study on the Diagnostic Performance of Mammography

With the aim of evaluating diagnostic performance and inter-observer variation of mammography, mammograms (MMGs) in 50 cases from the previous study were analyzed retrospectively. Without knowledge of either data from inspection and palpation diagnosis or clinical data, a study of MMGs reading by 10 physicians and 7 radiology technicians was carried out. The results showed that participating physicians and technicians, on the whole, were equally capable of detecting a mass and of differentiating breast cancer from normal cases and benign cases. In addition, variations in these capabilities among the physicians and technicians were nearly identical. Given the fact that the technicians engaged in the present study were specialists in mammography, these results suggest that technicians in general have the potential of reaching the same level of diagnostic performance as that of physicians if they are given suitable education and training, and that it is possible to establish a MMG reading system in which radiology technicians perform the MMG reading in the mass screening of breast cancer. Under these circumstances, the present results also suggest that it is urgently necessary to establish a mammographic technique for mass screening that is acceptable to the majority of MMG readers at other institutions.

Quantitative measurement of uptake of radiolabeled monoclonal antibody by means of planar data

Data obtained from planar images were used to measure the uptake of monoclonal antibody in organs and tumors. Background counts included in the region of interest were eliminated, and the attenuation of the photons emitted by the radionuclide through the intervening tissues was compensated for. The background counts and the intensity of the attenuation were determined from the results of phantom studies and numerical integration with a personal computer. The quantitative uptake of111In labeled anti-melanoma Monoclonal Antibody (ZME-018) in a melanoma lesion, the liver, and the bone marrow of a patient was measured by the planar method which we developed.

[Prospective study to assess the clinical efficacy of bone scintigraphy--some analyses of clinical data].

The value of preoperative bone scans in patients with primary breast and prostate cancer was evaluated prospectively. Of 414 patients with breast cancer, clinical stage I is 14, II is 219, IIIA is 59, IIIB is 39 and IV is 14. Of 88 patients with prostate cancer, clinical stage I is 14, II is 15, III is 18 and IV is 41. 11 percent of patients with breast cancer and 54 percent of patients with prostate cancer had bone metastases. Clavicle, ribs, thoracic spine, lumbar spine and pelvis metastasized most frequently. The incidences of bone metastases were 18.4% with Scirrhous carcinoma, 15.4% with Medullary tubular carcinoma and 3.8% with Papillotubular carcinoma. The methodology and results of ROC analysis were described in our other papers. Some results of data analysis were described in this paper.

Prospective study to assess the clinical efficacy of bone scintigraphy. - ROC analysis.

The value of preoperative bone scans in patients with primaly breast and prostate cancer was evaluated prospectively. The methodology and some clinical results were described previously. The clinical efficacy of the bone scan was assessed by using ROC analysis and we obtained the following results. 1) Preoperative bone scan of carcinomas of the breast is effective for patients with clinical stage IIIA, IIIB and IV. It is not so effective for patients with clinical stage I and II, but there is no denying the importance of it, because it provides a base-line scan for comparison to subsequent scans obtained in the postoperative period. 2) Preoperative bone scan of prostate carcinomas is effective, especially for clavicle, the ribs and the cervical spine, when compared with bone X-ray. 3) Bone scan is effective means for patients who were diagnosed uncertainly to have bone metastasis.