Prospective Randomized Trial for Image-Guided Biopsy Using Cone-Beam CT Navigation Compared with Conventional CT

Abstract

Purpose: To compare cone-beam computed tomography (CT) navigation vs conventional CT image guidance during biopsies.

Materials and methods: Patients scheduled for image-guided biopsies were prospectively and randomly assigned to conventional CT guidance vs cone-beam CT navigation. Radiation dose, accuracy of final needle position, rate of histopathologic diagnosis, and number of needle repositions to reach the target (defined as pullback to adjust position) were compared.

Results: A total of 58 patients (mean age, 57 y; 62.1% men) were randomized: 29 patients underwent 33 biopsies with CT guidance and 29 patients with 33 lesions underwent biopsy with cone-beam CT navigation. The average body mass index (BMI) was similar between groups, at 28.8 kg/m(2) ± 6.55 (P = .18). There was no difference between groups in terms of patient and lesion characteristics (eg, size, depth). The average lesion size was 29.1 ± 12.7mm for CT group vs 32.1mm ±16.8mm for cone-beam CT group (P < 0.59). Location of lesions was equally divided between the 2 groups, 20 lung lesions, 18 renal lesions and 20 other abdominal lesions. Mean number of needle repositions in the cone-beam CT group was 0.3 ± 0.5, compared with 1.9 ± 2.3 with conventional CT (P < .001). The average skin entry dose was 29% lower with cone-beam CT than with conventional CT (P < .04 accounting for BMI). The average estimated effective dose for the planning scan from phantom data was 49% lower with cone-beam CT vs conventional CT (P = .018). Accuracy, defined as the difference between planned and final needle positions, was 4.9 mm ± 4.1 for the cone-beam CT group, compared with 12.2 mm ± 8.1 for conventional CT (P < .001). Histopathologic diagnosis rates were similar between groups, at 90.9% for conventional CT and 93.9% for cone-beam CT (P = .67).

Conclusions: Cone-beam CT navigation for biopsies improved targeting accuracy with fewer needle repositions, lower skin entry dose, and lower effective dose for planning scan, and a comparable histopathologic diagnosis rate.

Figure 1:

1a is a picture of the anthropomorphic phantom with the cavities. 1b is a close up with the OSLDs inside the cavities.

Figure 1:

1a is a picture of the anthropomorphic phantom with the cavities. 1b is a close up with the OSLDs inside the cavities.

Figure 2:

59 year old female with history of spindle cell carcinoma and a newly enlarged retroperitoneal peri-aortic lymph node. 2a: axial image of the procedural CBCT demonstrating the planned needle path on an axial image displayed as the green and magenta line. 2b: Real-time fluoroscopy image with overlaid CBCT and the planned target are shown. The operator aligns the needle with the planned target seen as the green dot inside the magenta circle (blue arrow). 2c and d: CBCT images in the entry point view and progress view respectively obtained once the operator deemed that the target is reached. Yellow arrow points to the needle seen as a white dot on image C and white line on image D. A blue arrow highlights the planned path seen as white circle with green dot on image C and a magenta dotted line on image D. Both the needle and planned trajectory are superimposed in both images meaning that the needle was advanced along the desired trajectory to reach the specific target point. The deviation between the needle tip and the planned target was calculated based on the x, y, z coordinates of each.

Figure 2:

59 year old female with history of spindle cell carcinoma and a newly enlarged retroperitoneal peri-aortic lymph node. 2a: axial image of the procedural CBCT demonstrating the planned needle path on an axial image displayed as the green and magenta line. 2b: Real-time fluoroscopy image with overlaid CBCT and the planned target are shown. The operator aligns the needle with the planned target seen as the green dot inside the magenta circle (blue arrow). 2c and d: CBCT images in the entry point view and progress view respectively obtained once the operator deemed that the target is reached. Yellow arrow points to the needle seen as a white dot on image C and white line on image D. A blue arrow highlights the planned path seen as white circle with green dot on image C and a magenta dotted line on image D. Both the needle and planned trajectory are superimposed in both images meaning that the needle was advanced along the desired trajectory to reach the specific target point. The deviation between the needle tip and the planned target was calculated based on the x, y, z coordinates of each.

Figure 2:

59 year old female with history of spindle cell carcinoma and a newly enlarged retroperitoneal peri-aortic lymph node. 2a: axial image of the procedural CBCT demonstrating the planned needle path on an axial image displayed as the green and magenta line. 2b: Real-time fluoroscopy image with overlaid CBCT and the planned target are shown. The operator aligns the needle with the planned target seen as the green dot inside the magenta circle (blue arrow). 2c and d: CBCT images in the entry point view and progress view respectively obtained once the operator deemed that the target is reached. Yellow arrow points to the needle seen as a white dot on image C and white line on image D. A blue arrow highlights the planned path seen as white circle with green dot on image C and a magenta dotted line on image D. Both the needle and planned trajectory are superimposed in both images meaning that the needle was advanced along the desired trajectory to reach the specific target point. The deviation between the needle tip and the planned target was calculated based on the x, y, z coordinates of each.

Figure 2:

59 year old female with history of spindle cell carcinoma and a newly enlarged retroperitoneal peri-aortic lymph node. 2a: axial image of the procedural CBCT demonstrating the planned needle path on an axial image displayed as the green and magenta line. 2b: Real-time fluoroscopy image with overlaid CBCT and the planned target are shown. The operator aligns the needle with the planned target seen as the green dot inside the magenta circle (blue arrow). 2c and d: CBCT images in the entry point view and progress view respectively obtained once the operator deemed that the target is reached. Yellow arrow points to the needle seen as a white dot on image C and white line on image D. A blue arrow highlights the planned path seen as white circle with green dot on image C and a magenta dotted line on image D. Both the needle and planned trajectory are superimposed in both images meaning that the needle was advanced along the desired trajectory to reach the specific target point. The deviation between the needle tip and the planned target was calculated based on the x, y, z coordinates of each.

Figure 3:

The box plots depict the average skin entry dose recorded by the patient’s OSLDs. The median is thicker straight line and the average is thinner line with a star. The doses are provided in their initial mGy value. The P-value for the group comparison, based on a test of the log values mGy taking BMI into account, is statistically significant.

Figure 4

Figure 4 displays the CT beam on the left and the CBCT beam on the right. The CBCT has a single x-ray source that delivers a wide beam with a single rotation while the CT has several x-ray sources (only one depicted) that radiate a narrow area requiring multiple rotations while the table/patient are moving to radiate an entire area.