Final answer:
The diagnosis of idiopathic granulomatous mastitis is primarily through mammography and ultrasound, followed by fine-needle aspiration and biopsy for definitive confirmation.
Step-by-step explanation:
The diagnosis of idiopathic granulomatous mastitis typically involves b) Mammography and ultrasound, but more definitive diagnosis generally requires the use of c) Fine-needle aspiration (FNA) and biopsy. These techniques help to identify the granulomatous inflammation characteristic of this condition without an underlying infection or other evident etiology. While clinical examination can provide important clues, it's usually not sufficient to establish a diagnosis. Blood culture is less relevant in this context as idiopathic granulomatous mastitis is not caused by a systemic infection. Therefore, for a comprehensive assessment and diagnosis, a combination of imaging techniques and tissue sampling is necessary.