CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese application JP 2020-090860, filed on May 25, 2020, the contents of which is hereby incorporated by reference into this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lesion detection technique in a medical image diagnosis apparatus, and more particularly, to reduction of erroneous detection.

2. Description of the Related Art

In recent medical examination of breast cancer, in addition to mammography in related art, medical examination performed by an ultrasonic diagnosis apparatus is being performed in combination. Since it is necessary to interpret a large amount of ultrasonic images in ultrasonic examination and a burden on a medical worker is large, development of a computer-aided detection (CADe) performed by a computer is expected.

Since the breast ultrasonic image exhibits various appearances depending on an age of a subject, experience of an examiner, types of imaging apparatus, and the like in addition to types of lesions, detection difficulty is high among medical images. In particular, since a region showing a lesion is also present in normal tissue, erroneous detection tends to occur in many cases. In order to prevent a decrease in medical examination efficiency of an examiner, it is important to reduce erroneous detection of a machine when CADe is applied to a breast ultrasonic image.

As a general technique for reducing the erroneous detection in object detection, JP-A-2018-1901321 discloses a technique for specifying erroneous detection by using a difference between a foreground and a background and a variation amount of an aspect ratio of a detection rectangle. Further, as a technique for reducing the erroneous detection of a lesion in a breast ultrasonic image, JP-A-2015-154918 discloses a technique for detecting a lesion candidate region, grasping an anatomical structure in a breast, and determining whether there is a value of performing medical diagnosis on a detection result based on a relationship between the lesion candidate region and the anatomical structure.

In the method of reducing the erroneous detection based on the background difference described in JP-A-2018-190132, a region other than the foreground in the image is used as a background region. However, since a mammary gland is present only in a specific region in the breast ultrasonic image, it is difficult to determine the erroneous detection based on a difference between a region of a lesion of the detected mammary gland and the other region, and it is difficult to appropriately reduce the erroneous detection. In addition, the breast ultrasonic image is complicated and unclear, and it is considered that the analysis of an anatomical structure as disclosed in JP-A-2015-154918 requires a high processing cost, and thus real-time computer-aided detection is difficult.

SUMMARY OF THE INVENTION

The invention determines a normal tissue region corresponding to a detected lesion candidate region in an analysis target image in consideration of structural features of lesion tissue and normal tissue around the lesion tissue, and evaluates validity of the lesion candidate region by using information of the determined normal tissue region.

That is, a medical image processing apparatus of the invention includes: a detection unit configured to detect a lesion candidate region; and a validity evaluation unit configured to evaluate validity of the lesion candidate region by using a normal tissue region corresponding to the detected lesion candidate region.

For example, the medical image processing apparatus of the invention includes an image processing unit configured to process a medical image acquired by a medical image imaging apparatus. The image processing unit includes a detection unit configured to detect a lesion candidate region from the medical image, and a validity evaluation unit configured to evaluate validity of a detection result of the detection unit. The validity evaluation unit includes a normal tissue extraction unit configured to extract a normal tissue region from the medical image by using position information of the lesion candidate region detected by the detection unit, and a feature extraction unit configured to calculate a variation feature amount indicating a difference between features of the lesion candidate region and the normal tissue region, and evaluates validity of the detection result by using the variation feature amount calculated by the feature extraction unit.

A medical imaging apparatus according to the invention includes: an imaging unit configured to acquire a medical image; and an image processing unit configured to analyze the medical image acquired by the imaging unit. The image processing unit has a configuration of the medical image processing apparatus described above. The medical imaging apparatus is, for example, an ultrasonic imaging apparatus.

According to the invention, it is possible to reduce erroneous detection in a lesion detection in a medical image and to improve medical examination efficiency of an operator.

