A preliminary clinical study of automatic registration ultrasound-CT/MR fusion imaging based on liver vessel trees / 中华超声影像学杂志

Objective To explore the feasibility and convenience of automatic registration ultrasound-CT/MR fusion imaging based on hepatic vessel trees. Methods The PercuNav fusion imaging system of Philips Epiq 7 was used to perform ultrasound-CT/MR fusion imaging on 22 patients with focal liver lesions detected by contrast-enhanced CT or MR.Both automatic registration ultrasound-CT/MR fusion imaging based on hepatic vessel trees and the conventional ultrasound-CT/MR fusion imaging based on internal anatomic landmarks were employed for alignment in these patients.The results including the success rate of registration,duration time of initial registration,error of initial registration,number of times of fine-tuning, duration time of fine-tuning and the overall duration time of registration were compared between these two methods.Results The success rates of registration,duration time of initial registration,errors of initial registration,numbers of times of fine-tuning,duration time of fine-tuning and the overall duration time of registration for automatic registration ultrasound-CT/MR fusion imaging based on hepatic vessel trees and the conventional ultrasound-CT/MR fusion imaging based on internal anatomic landmarks were 72.73% and 95.45%,16.5 s (10~30 s) and 13 s (8~24 s),3 mm (1~14 mm) and 14 mm (2~43 mm),0 time (0 to 2 times) and 1 time (0~3 times),0 s(0~46 s) and 30 s (0~88 s),and 20 s (12~61 s) and 42 s (9~102 s),successively and respectively. There was no statistically significant difference in the success rates between these two methods ( P >0.05).The duration time of initial registration of conventional method was less than that of automatic registration method( P <0.05).The error of initial registration,number of times of fine-tuning,duration time of fine-tuning and the overall duration time of registration of automatic registration method were superior to those of conventional method ( P < 0.05).Conclusions Automatic registration ultrasound-CT/MR fusion imaging based on hepatic vessel trees is feasible. It is also more convenient than conventional ultrasound-CT/MR fusion imaging based on internal anatomic landmarks.

Optimal slice thickness for cone-beam CT with on-board imager

Purpose: To find the optimal slice thickness (Δτ) setting for patient registration with kilovoltage cone-beam CT (kVCBCT) on the Varian On Board Imager (OBI) system by investigating the relationship of slice thickness to automatic registration accuracy and contrast-to-noise ratio. Materials and method: Automatic registration was performed on kVCBCT studies of the head and pelvis of a RANDO anthropomorphic phantom. Images were reconstructed with 1.0 ≤ Δτ (mm) ≤ 5.0 at 1.0 mm increments. The phantoms were offset by a known amount, and the suggested shifts were compared to the known shifts by calculating the residual error. A uniform cylindrical phantom with cylindrical inserts of various known CT numbers was scanned with kVCBCT at 1.0 ≤ Δτ (mm) ≤ 5.0 at increments of 0.5 mm. The contrast-to-noise ratios for the inserts were measured at each Δτ. Results: For the planning CT slice thickness used in this study, there was no significant difference in residual error below a threshold equal to the planning CT slice thickness. For Δτ > 3.0 mm, residual error increased for both the head and pelvis phantom studies. The contrast-to-noise ratio is proportional to slice thickness until Δτ = 2.5 mm. Beyond this point, the contrast-to-noise ratio was not affected by Δτ. Conclusion: Automatic registration accuracy is greatest when 1.0 ≤ Δτ (mm) ≤ 3.0 is used. Contrast-to-noise ratio is optimal for the 2.5 ≤ Δτ (mm) ≤ 5.0 range. Therefore 2.5 ≤ Δτ (mm) ≤ 3.0 is recommended for kVCBCT patient registration where the planning CT is 3.0 mm

Registration of Cadaver's Sectioned Images to Patient's Head MRIs / 대한의료정보학회지

OBJECTIVE: Cadaver's sectioned images with high resolution and real color could be used as the source of realistic three-dimensional images. If the sectioned images are registered to a patient's MRIs, three-dimensional images with high resolution and real color that fit the patient, can be produced; the three-dimensional images enable realistic virtual surgery for the patient. The objective of this study was to verify the registration of a cadaver's sectioned images to a patient's head MRIs. METHODS: The sectioned images of the heads of cadaver were associated with segmented images selected at 3 mm intervals. The patient had his head MR scanned at 3 mm intervals; the MRIs were segmented. Software to register the cadaver's sectioned images to the patient's MRIs was developed. On this software, the corresponding dots were identified on both the sectioned images and the MRIs either manually or automatically using segmented images. RESULTS: The registered sectioned images corresponded to the patient's MRIs. Both manual and automatic registrations were satisfied. CONCLUSION: Further study is needed for registering sectioned images to actual patients.