Computer aided diagnosis (CAD) is one of the potential technologies in today's medical world that assist doctors to interpret and evaluate medical images in a short time. CAD offers support to medical professionals to make decisions on possible diseases. Various systems and approaches are implemented to serve this technology, and many hospitals have deployed the system for diagnosis of diseases. The detection of the proportion of disease would aid in determining if more in-depth tests are required for confirmation of the condition, hence avoiding risky biopsies. This survey focuses on such methodologies implemented by authors of several works to detect lung infections by analyzing tissue patterns and inflammations in lungs and classifying the same. Along with this, work related to the patient database system is also reviewed and a comparison is made between the works.
