Clinical application of a CT-guided lung biopsy system: core needle biopsy at the IVR center

Prior reports of CT-guided lung biopsy of the small lung nodules of less than 2 cm have been unsatisfactory. In January 1998, we began a preliminary study of CT-guided lung biopsy in our conventional CT room. With the basic results achieved, we constructed a novel CT-guided lung biopsy system. Together with Hitachi Corporation we have developed CT, the Radix Prima, exclusive for interventional procedures especially for CT-guided lung biopsy. As reconstruction delay time of the procedures has been shortened from 1.0 sec. to 0.6 sec., real time CT fluoroscopy monitoring is possible on the Cathode Ray Tube (CRT) monitor in the CT room, very closed to the patient. Multiple confirmations of the tip of the biopsy needle have been possible with this specially equipped CT. A semi-automatic-type needle have been selected for reliable biopsy, because the old fully-automatic-type needle was very heavy and easily misfired. Multiple punctures have been also used, because single punctures have a greater risk of obtaining inadequate specimens. In our clinical study at our IVR center, the subjects comprised 41 patients (26 males, 15 females, ranging in age from 34 to 79, mean 64 years old). The mean nodule diameter was 1.9 cm, the mean distance from skin surface to lesion was 5.5 cm, and the mean number of punctures was 3.0. The biopsy results included 23 malignancies. In 13 patients the results were benign tumors or specific inflammation. In 4 patients the results were nonspecific inflammation. In only 1 patient was the specimen inadequate. There was no false negative. The correct rate of benign/malignant diagnoses was 98%. A complication of pneumothorax was observed in 22 patients, but all were improved by conservative treatment. Pulmonary hemorrhage was observed in 21 patients, 7 of whom also had hemoptysis. Each of these patients also responded to conservative treatment from specialist medical staff at the IVR center. The 98%accuracy of our results indicates that multiple punctures using a semi-automatic-type biopsy needle and multiple confirmations of the needle tip on our method of real time CT fluoroscopy are extremely important for CT-guided lung biopsy of small lung nodules of less than 2 cm.