Figure 4. .

When performing an acquisition with a very low CTDI at 0.11 mGy, image noise, well seen outside of the chest, can mimic a miliary disease on thin axial slice (a) and MIP reformat (b), even though applying an iterative reconstruction algorithm. A follow-up CT with a CTDI at 0.29 mGy (b) reduces noise, allowing to exclude micronodules. These CT were performed in a context of recurrent pneumothorax in a young patient with endometriosis (not shown). CTDI, CT dose index; MIP, maximum intensity projection.