1. Field of the Invention
The present invention relates to a system and method of managing a medical image. More particularly, the present invention relates to a system and method of managing a medical image, in which the medical image after converting density can be rapidly displayed on a display surface of a client terminal.
2. Description Related to the Prior Art
A medical image managing system is widely used in a hospital or other medical facilities, for managing medical images in a form of electronic data, the medical images being formed by a modality unit such as a CR apparatus (computed radiography apparatus), DR apparatus (digital radiography apparatus), CT apparatus (computed tomography apparatus) or the like. The medical image managing system includes an image server and a client terminal. The image server stores the medical images formed by the modality unit. The client terminal is manipulated by a doctor or physician. The image server and the client terminal are connected to an internal network disposed in a hospital. The client terminal communicates with the image server through the internal network, so that the medical image filed in the image server is read out and displayed on a monitor.
In a medical facility, the use of a portable terminal apparatus as the client terminal in the medical image managing system has been increased, such as a PDA (personal digital assistant), smart phone (high performance mobile telephone), tablet and the like. The portable terminal apparatus is connected to a wireless LAN (wireless local area network) in the internal network, or to a telephone line of the mobile telephone, so that viewing of the medical image is possible in various places.
For diagnosis of the medical image, density conversion is performed to convert density of the medical image to enhance its high or low density portions for the purpose of facilitating the diagnosis according to a body part of the medical image or a modality of the modality unit. The medical image is stored in the image server in a format of a multi-level gradation image (high resolution image) with gradation of 9-16 bits per one pixel, or lossless JPEG image without degradation, The density conversion of the medical image is to determine a center value of the gradation and a width of the gradation about the center value for the medical image of the multi-level gradation, for converting the gradation of the medical image. The density conversion is generally referred to as window level conversion.
For example, the medical image managing system of JP-A 2012-100899 includes the image server and the client terminal. The image server processes the medical image in the density conversion. The client terminal causes a monitor to display a density-converted medical image after the density conversion in the image server. In the medical image managing system, it is possible for the client terminal readily to display the density-converted medical image on the monitor after readout from the image server.
The medical image managing system of JP-A 2000-293528 includes the image server and the client terminal. The image server transmits the medical image to the client terminal. The client terminal processes the medical image in the density conversion after reception from the image server, and causes a monitor to display the density-converted medical image. In the medical image managing system, the density conversion is performed in the client terminal. Should initial conversion of density be insufficient, the density conversion is performed again, so that processing time for the density conversion may be long. However, transmission of the medical image from the image server after the density conversion is unnecessary. So the total of the processing time can be shortened.
In general, it is necessary rapidly to display the density-converted medical image at the client terminal in the medical image managing system for medical diagnosis. However, displaying may be slower according to a condition of using the medical image managing system. For example, in the medical image managing system of JP-A 2012-100899, time for transmitting the medical image from the image server to the client terminal is longer assuming that a communication speed between the image server and the client terminal is low. Displaying the density-converted medical image at the client terminal becomes slow. Communication time of the medical image is changed because the communication speed changes according to a place of the communication in case the portable terminal apparatus is connected to the image server by the wireless LAN or the telephone line of the mobile telephone. Also, the communication time changes with dependency to a data size.
In the medical image managing system in JP-A 2000-293528, rapidity in displaying the density-converted medical image may be varied according to a structure of the system based on performance of the client terminal in use, a type of the software and the like. For example, should the portable terminal apparatus be an old type, displaying requires time because of a low level of the communication speed or a processing time of data. In case the portable terminal apparatus of a new type is used, displaying can be rapid owing to high performance.
Rapidity of displaying the density-converted medical image is influenced by a construction, a communication condition or the like of the medical image managing system. In relation to a first structure for density conversion in the image server and a second structure for density conversion in the client terminal, which of the first and second structures can display the density-converted medical image reliably earlier than the remainder cannot be determined. It is difficult to determine which of the two should be selected for the density conversion in an effective manner.