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Approximately 1300 radiological exams are carried out during a weekday at Samsung Medical Center and of that 50% of those exams are softcopy read and archived in PACS. The presentation discusses the management of a centralized PACS for efficient softcopy operation.

Samsung Medical Center (SMC) is a brand new hospital of about 1,000 patient beds which has implemented a successful picture archiving and communications system (PACS) since November 1994. The goal of SMC PACS was to implement a large-scale filmless PACS in four phases. SMC chose the turn-key based implementation method regarding the time frame. The departments of orthopedic surgery, neurosurgery, neurology, emergency room and surgical intensive care unit were selected for the first phase of PACS implementation. SMC reduced the confusion and the discomfort of medical doctors during the transition period of film and PACS operation. This paper describes the process of the clinical implementation of SMC PACS; goal and scope, implementation strategy, system installation and training, and clinical operation and maintenance.

Summary: Purpose: To assess the magnetic resonance imaging (MRI), positron emission tomography (PET), pathology, and clinical findings of patients with the MRI feature of white-matter change (WMC) in the anterior temporal lobe. Methods: Fifty-six patients with pathologically proven mesial temporal sclerosis were included in this study. MRI and 18F-2-deoxyglucose-(FDG) PET images were obtained before surgery in all patients. The patients were divided into two groups according to the presence of WMC on their MRI. WMC consists of an indistinct gray-white matter demarcation and an increased signal intensity of the anterior temporal lobe on T2-weighted images. The two groups were then compared in terms of MRI, PET, pathology, and clinical features. Results: The MRI feature of WMC was observed in 18 (32%) of the 56 patients. PET images of those patients revealed more severe hypometabolism of the ipsilateral temporal lobes (p > 0.05). In terms of histologic findings, larger numbers of het-erotopic neurons were observed in the anterior temporal lobe white matter of these patients who also shared the following clinical features: earlier seizure onset, frequent history of febrile convulsions, and favorable surgical outcomes. Conclusions: The MRI feature of WMC is an additive sign for correct seizure lateralization and may be related to a favorable surgical outcome in patients with temporal lobe epilepsy.

As increasing number of medical facilities are introducing PACS, the needs to interconnect PAC systems are also increased. Although the primary goal of PACS is to enable distribution of radiologic images electronically within hospital and thus assist patient care more efficiently, inter-networking of multiple facility PAC systems can create additional application area and bring about clinical impact. By inter-networking multiple facility PACS, exams can be automatically routed to the remote radiologist when the local radiologist is not available such as during the off- duty hours and vacations. Physicians and radiologists can also benefit from the inter-networking of PACS by making telesconsultation of special cases with remote subspecialty radiologists which can lead to improved diagnostic accuracy and confidence. In this study, we attempted to develop an inter-networking system among the multi-facility PAC systems which can be used for image data transfer and telesconsultation by establishing the ISDN intranet and developing a Web based DICOM white board.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The purpose of this paper is to describe the transition of a 1,100 beds tertiary hospital from 50 percent softcopy operation to full PACS operation. For the past 2 years, radiologists and clinicians have been using PACS to provide softcopy services to the outpatient clinics and inpatient wards of orthopedics surgery, neurosurgery and neurology as well as emergency room, surgical intensive care unit, medical intensive unit, pediatrics intensive care unit and neonatal intensive care unit. The examinations requested by these departments account for about 50 percent of hospital's radiological exams. In September 1996, we began the second phase of PACS implementation and installed additional workstations in the remaining wards and clinics, interfaced to PACS additional imaging modalities, and increased the capacity of both the image server and optical juke boxes. As of January 1997, we are in the final phase of moving away from conventional film system to full PACS operation.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

All magnetic resonance images are blurred as a result of an inherent decay of spin-echo signals during data acquisition due to spatially-varying and object-dependent transverse relaxation. The extent of the blur depends on the transverse relaxation time (T2) of the object and the data acquisition time used. An iterative method that corrects for such object-dependent anisotropic blurs in hydrogen magnetic resonance images is described. The method involves mathematical generation of the components of the spin-echo signals that gives rise to blurs in the images — using initial estimates of the distribution of spin-density and transverse relaxation time — and subtracting those component from the distorted spin-echo signals. Images reconstructed from such corrected signals yield improved estimates of the T2-weighted spin-density distributions. The method was tested on mathematical phantoms.

Purpose: To evaluate the usefulness of functional MR imaging (fMRI) for the determination of languagedomi-nance and to assess differences in language lateralization according to activation task or activated area.Materials and Methods: Functional maps of the language area were obtained during word generation tasks (noun andverb) and a reading task in ten patients (9 right handed, 1 left handed) who had undergone the Wada test. MRexaminations were performed using a 1.5T scanner and the EPI BOLD technique. The SPM program was employed for thepostprocessing of images and the threshold for significance was set at p

Mediastinal interfaces on a chest radiograph result from contact between mediastinal structures and the adjacent lung, while mediastinal lines result from contact between the two lungs across the midline. A variation of mediastinal interface is mediastinal stripe, a narrow band produced by contact of both sides of a mediastinal structure with the lungs. Alterations in mediastinal interfaces and lines may be due to variations in normal anatomy, or may reflect the presence of a abnormalities within the mediastinum. Familiarity with the various normal mediastinal interfaces and lines, and the changes that occur with disease is important for the interpretation of the chest radiograph and in the diagnosis of mediastinal abnormalities. The purpose of this pictorial essay is to illustrate the most imortant normal and abnormal interfaces and lines and also to correlate radiography and CT findings.

A case of primary adenosquamous carcinoma of the liver is reported. A large cystic mass with irregrlar enhancing wall was seen in the left lobe of the liver ; multiple hepatic cysts and metastatic nodules were scattered in both lobes. Sonoguided needle biopsy was performed and onhistopathology, adenosquamous carcinoma was diagnosed. The radiologic and pathologic relationships of this unusual neoplasm are discussed.

Iterative data refinement (IDR) is a general procedure for estimating data that would have been collected by an ideal measuring device from data that were collected by an actual measuring device. We show that IDR is general enough to encompass such well-accepted image recovery methods as the Gerchberg-Saxton algorithm and the error reduction and hybrid input-output methods of Fienup. The generalizations provided by IDR give new insights into the nature of such algorithms and, in particular, allow us to introduce the notion of relaxation into them. Along similar lines, DR provides a common framework within which new algorithms can be developed for improved magnetic resonance imaging (MRI). We apply the approach of IDR to a specific problem in MRI, namely, to the correction of spatially dependent blurs due to transverse relaxation. The algorithm is designed to reconstruct 12-weighted spin density images with improved spatial resolution. The practical computational significance of using the IDR approach is illustrated by the reconstruction of mathematical phantoms. We find that overrelaxation of the algorithm can improve computational speed by up to a factor of five.

Iterative Data Refinement (abbreviated IDR) is a general procedure which encompasses many special procedures for image reconstruction and for related problems. It is a procedure for estimating data that would have been collected by an idealized measuring device from data that were collected by an actual measuring device. Such approaches have been applied successfully in areas of reconstruction in x-ray tomographic radiology. In fact, IDR is general enough to encompass standard approaches to data recovery, such as the Error-Reduction and the Hybrid Input-Output methods. Along similar lines, IDR provides a common framework within which new algorithms can be developed for improved magnetic resonance imaging (MRI). We have applied and implemented the approach of IDR to a specific problem in MRI, namely to the correction of spatially-dependent blurs due to short local transverse relaxation (T2) values. The algorithm is designed to reconstruct T2-weighted spin density images with improved spatial resolution. The practical computational significance of using the IDR approach will be illustrated by the reconstruction of mathematical phantoms. We have found that over-relaxation of the algorithm improves computational speed by up to a factor of five.