3D CT delivers thoracoscopic surgery guidance
The use of CT advanced visualization software enables the safe and effective placement of fiber-coated microcoils used to guide video-assisted thoracoscopic surgical (VATS) excision of small peripheral lung nodules, according to a study published in this month’s issue of Radiology.
Small, growing lung nodules raise the possibility of early lung cancer; however, CT imaging alone can not differentiate these nodules as malignant or benign. Excision biopsy, using VATS, removes the nodule at one setting and is appealing to both physicians and patients, according to the authors of a prospective study conducted in the departments of radiology, pathology and respiratory medicine at Vancouver General Hospital in Vancouver, B.C.
“The purpose of the current study was to prospectively assess a CT-guided microcoil localization technique in 69 patients with 75 small peripheral lung nodules, with successful VATS resection as the primary outcome,” the authors wrote.
Using previous CT scans for guidance, localizing CT scanning (performed on a Siemens Healthcare 16-slice Sensation CT system) was performed to identify the suspicious nodule, plan the access route, guide the sterile skin preparation, and to place local anesthetic in the overlying chest wall. Microcoil (Vortx-18, Diamond Shape; Boston Scientific) localizations was performed or supervised by an interventional radiologist.
The researchers noted that the mean duration for CT-guided placement of the microcoil was 33 minutes.
Once the coil was placed, a postprocedural larger-volume CT scan was obtained to assess the final position of the microcoil relative to the nodule and the pleural space and to assess for the presence of postprocedural hemorrhage, as indicated by new airspace consolidation and pneumothorax, according to the authors
The CT images were then reformatted into a 3D volume rendered image that showed the relationship between the microcoil and the ribs to assist in port placement for the VATS resection.
The patient was then transferred for the VATS procedure, which occurred within 1 to 6 hours of the final CT scan. The surgeon used the 3D volume rendered CT image as a guide for their excision, which was confirmed with fluoroscopy at the time of surgery.
“With use of this technique, a modification of CT-guided fine-needle aspiration biopsy, 100 percent of the nodules were localized in the current study,” the authors reported. “Complete VATS resection of these nodules was successful in 97 percent of cases; this represents a substantial increase in the rate of successful VATS excision compared with the reported success rate of 54 percent for non-guided VATS.”
Of equal importance, the team found that intraoperative management can be based on the frozen-section histopathologic diagnosis of the excised nodule, because the marking and excision technique did not interfere with the final histopathologic diagnosis.
“Although the lesion was directly punctured in 59 (79 percent) cases, the localization technique did not impede the histopathologic processing or interpretation of specimens, and no local cancer recurrences were documented,” the authors noted. “The use of this technique may help to address the diagnostic dilemma of increasing numbers of small peripheral lung nodules that are detected incidentally or found at serial chest CT to be growing.”
Small, growing lung nodules raise the possibility of early lung cancer; however, CT imaging alone can not differentiate these nodules as malignant or benign. Excision biopsy, using VATS, removes the nodule at one setting and is appealing to both physicians and patients, according to the authors of a prospective study conducted in the departments of radiology, pathology and respiratory medicine at Vancouver General Hospital in Vancouver, B.C.
“The purpose of the current study was to prospectively assess a CT-guided microcoil localization technique in 69 patients with 75 small peripheral lung nodules, with successful VATS resection as the primary outcome,” the authors wrote.
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| Coronal volume-rendered surface-shaded display CT image shows a microcoil positioned through a 10-mm-diameter solid nodule (straight arrow) in the left lower lobe of the lung. This depiction of the relationship between the proximal end of the microcoil (curved arrow) and the overlying ribs assisted the surgeons in placing a port for VATS excision. Image and caption courtesy of the Radiological Society of North America. |
The researchers noted that the mean duration for CT-guided placement of the microcoil was 33 minutes.
Once the coil was placed, a postprocedural larger-volume CT scan was obtained to assess the final position of the microcoil relative to the nodule and the pleural space and to assess for the presence of postprocedural hemorrhage, as indicated by new airspace consolidation and pneumothorax, according to the authors
The CT images were then reformatted into a 3D volume rendered image that showed the relationship between the microcoil and the ribs to assist in port placement for the VATS resection.
The patient was then transferred for the VATS procedure, which occurred within 1 to 6 hours of the final CT scan. The surgeon used the 3D volume rendered CT image as a guide for their excision, which was confirmed with fluoroscopy at the time of surgery.
“With use of this technique, a modification of CT-guided fine-needle aspiration biopsy, 100 percent of the nodules were localized in the current study,” the authors reported. “Complete VATS resection of these nodules was successful in 97 percent of cases; this represents a substantial increase in the rate of successful VATS excision compared with the reported success rate of 54 percent for non-guided VATS.”
Of equal importance, the team found that intraoperative management can be based on the frozen-section histopathologic diagnosis of the excised nodule, because the marking and excision technique did not interfere with the final histopathologic diagnosis.
“Although the lesion was directly punctured in 59 (79 percent) cases, the localization technique did not impede the histopathologic processing or interpretation of specimens, and no local cancer recurrences were documented,” the authors noted. “The use of this technique may help to address the diagnostic dilemma of increasing numbers of small peripheral lung nodules that are detected incidentally or found at serial chest CT to be growing.”