It is not possible to give precise answers to all your queries, because to be able to do that we need to see the actual CT Films and then take a decision. However, a few facts which can be of some use to you are:
Fine needle aspiration cytology (FNAC) does not always succeed and therefore it is mandatory that we see the films and only if we expect that the yield from the FNAC would be significant then one would like to do the FNAC. Usually in a peripheral lesion, the yield is satisfactory and the positivity rate is to the tune of 90-95%, that is, in over 90% of patients we succeed in hitting the lesion and taking out the cells from there which will give us some diagnosis. However, in about 5-10% of patients, either one is not able to hit the lesion because it is located very close to a vital structure or the cells aspirated out of the lesion do not give a firm diagnosis and then we have to proceed for surgery and an open biopsy can be taken.
For most FNAC, one day or overnight admission is required. Typically a patient is admitted in the morning, FNAC carried out and discharged the next day. However, there is a complication rate of 8-10% in which the needle when it goes through the lungs, produces some air leak and air may collect in the chest which may compress the lungs. Out of those 8-10% of patients where the air leak can compress the lung, 1 in 10 may require a chest tube placement so that lung expands once again and air is taken out. In other 9 out of those 10 patients, one need not do anything and just observe for a couple of days and usually the air gets resolved spontaneously and the leak closes off and lung expands.
The fine needle biopsy as the name suggests is performed using a fine needle which is inserted through the chest wall and then CT scans are performed which guide the needle to the proper place in to the lesion and suction is applied on the needle so that a few cells are sucked out from that lesion. These cells are then subjected to microscopic examination and different staining techniques are used to decide whether it is cancer or it is just infection or some other pathology. It is usually not at all a painful procedure and we do give local anaesthesia in the chest wall so that it is very comfortable. Majority of patients are up and about walking within couple of hours of the procedure and the over night admission is basically for observing for any complication that potentially may develop but that happens in less than 8-10% of cases.