This document summarizes recent work on content-based image retrieval (CBIR) techniques for medical images. It discusses several methods used for CBIR, including shape-based, texture-based, and feature selection methods. Recent CBIR works are surveyed that use approaches like support vector machines, nearest neighbor algorithms, and relevance feedback. While progress has been made, the document notes there are still research gaps around bridging the semantic gap between low-level image features and high-level concepts, and improving retrieval accuracy and efficiency.