Hi, a granuloma results from immune cells fighting an infection, or from some other immune system reaction. So it doesn't typically raise the same alarm bells about a possible cancer that a nodule might.
By itself, there's not much reason to be worried: "Granulomas in people without symptoms almost never require treatment or even follow-up imaging tests."
The metal wire shouldn't have caused any false image: "Patients were scanned wearing several different types of bras. No bra, including those with metal, caused artifacts that influenced the diagnostic accuracy of the images."
If the sequins weren't metal, that probably shouldn't matter either.
But a bra can reduce the amount of radiation received, which was the main point of that study.
As a general rule, a scan alone cannot absolutely rule out any cancer. The radiologist would consider all the relevant factors and make the judgment*.
The only way to be 100% sure would be a biopsy, which at this point would be more risk than that's worth -- unless there are risk factors like other cancer, smoking history, breathing in chemicals and so on. Plus any symptoms, and the reason that the CT was done in the first place. You might get a followup scan (in 3-12 months) to see if things change.
* Granulomas can apparently have a distinctive pattern of calcification, if yours have that, the judgment is much more certain. 'Calcification' means that calcium gets deposited there, as part of an immune reaction. That shows up easily on a scan just like bone does.
"But a bra can reduce the amount of radiation received, which was the main point of that study."
That study was done in mammograms, not in lung CTs.
Pulmonary nodules can either be noncalcified or calcified, the former which are nonspecific and the latter which are compatible with calcified granulomas. Calcified granulomas are typically benign and usually represent sequela of old healed granulomatous disease (e.g., inactive tuberculosis, histoplasmosis, sarcoidosis, etc.). While noncalcified nodules are usually followed with CT to demonstrate at least 2-year stability and thus benignity, calcified granulomas do not warrant follow-up.