Virtual navigator automatic registration technology in abdominal application.

Automatic Registration between Real-Time Ultrasonography and Pre-Procedural Magnetic Resonance Images: A Prospective Comparison between Two Registration Methods by Liver Surface and Vessel and by Liver Surface Only

Objective To compare three-dimensional contrast-enhanced ultrasound (3DCEUS) fusion imaging and computed tomography (CT) fusion imaging in evaluating ablation margin (AM) after radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC). Methods The 3DCEUS images of 60 patients before and after RFA were collected. The AM was evaluated by the self-developed 3DCEUS fusion imaging technique. The consistency of AM evaluation was compared between 3DCEUS and CT fusion imaging. The risk factors of local tumor progression (LTP) including AM were analyzed. Results The registration success rate of 3DCEUS fusion imaging was 96.7% (58/60). Thirty-one cases were in the AM<5 mm group, and 27 cases were in the AM≥5 mm group. The consistency of AM evaluation between 3DCEUS and CT fusion imaging was good (Kappa coefficient=0.895, P<0.001). During a follow-up period ranging 4.2 to 18 months, LTP was identified in 5 tumors (8.6%, 5/58). The incidence of LTP with the AM<5 mm was higher than that with the AM≥5 mm(P=0.033). Conclusions 3DCEUS fusion imaging is feasible for AM evaluation immediately after RFA with high consistency with CT fusion imaging. AM<5 mm evaluated on 3DCEUS fusion immediately after RFA is a risk factor for LTP. Key words: Contrast-enhanced ultrasound, three-dimensional; Carcinoma, hepatocellular; Fusion imaging; Radiofrequency ablation

Fusion imaging is an emerging technique that combines real-time ultrasound examination with images acquired previously using other modalities, such as computed tomography (CT), magnetic resonance imaging and positron emission tomography. The primary aim of this study was to evaluate the feasibility of fusion imaging in patients with suspicion of ovarian or peritoneal cancer. Secondary aims were: to compare the agreement of findings on fusion imaging, CT alone and ultrasound imaging alone with laparoscopic findings, in the assessment of extent of intra-abdominal disease; and to evaluate the time required for the fusion imaging technique. Patients with clinical and/or radiographic suspicion of advanced ovarian or peritoneal cancer who were candidates for surgery were enrolled prospectively between December 2019 and September 2020. All patients underwent a CT scan and ultrasound and fusion imaging to evaluate the presence or absence of the following abdominal-cancer features according to the laparoscopy-based scoring model (predictive index value (PIV)): supracolic omental disease, visceral carcinomatosis on the liver, lesser omental carcinomatosis and/or visceral carcinomatosis on the lesser curvature of the stomach and/or spleen, involvement of the paracolic gutter(s) and/or anterior abdominal wall, involvement of the diaphragm and visceral carcinomatosis on the small and/or large bowel (regardless of rectosigmoid involvement). The feasibility of the fusion examination in these patients was evaluated. Agreement of each imaging method (ultrasound, CT and fusion imaging) with laparoscopy (considered as reference standard) was calculated using Cohen's kappa coefficient. Fifty-two patients were enrolled into the study. Fusion imaging was feasible in 51 (98%) of these patients (in one patient, it was not possible for technical reasons). Two patients were excluded because laparoscopy was not performed, leaving 49 women in the final analysis. Kappa values for CT, ultrasound and fusion imaging, using laparoscopy as the reference standard, in assessing the PIV parameters were, respectively: 0.781, 0.845 and 0.896 for the great omentum; 0.329, 0.608 and 0.847 for the liver surface; 0.472, 0.549 and 0.756 for the lesser omentum and/or stomach and/or spleen; 0.385, 0.588 and 0.795 for the paracolic gutter(s) and/or anterior abdominal wall; 0.385, 0.497 and 0.657 for the diaphragm; and 0.336, 0.410 and 0.469 for the bowel. The median time needed to perform the fusion examination was 20 (range, 10-40) min. Fusion of CT images and real-time ultrasound imaging is feasible in patients with suspicion of ovarian or peritoneal cancer and improves the agreement with surgical findings when compared with ultrasound or CT scan alone. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

The registration of a three-dimensional (3D) ultrasound (US) image with a computed tomography (CT) or magnetic resonance image is beneficial in various clinical applications such as diagnosis and image-guided intervention of the liver. However, conventional methods usually require a time-consuming and inconvenient manual process for pre-alignment, and the success of this process strongly depends on the proper selection of initial transformation parameters. In this paper, we present an automatic feature-based affine registration procedure of 3D intra-operative US and pre-operative CT images of the liver. In the registration procedure, we first segment vessel lumens and the liver surface from a 3D B-mode US image. We then automatically estimate an initial registration transformation by using the proposed edge matching algorithm. The algorithm finds the most likely correspondences between the vessel centerlines of both images in a non-iterative manner based on a modified Viterbi algorithm. Finally, the registration is iteratively refined on the basis of the global affine transformation by jointly using the vessel and liver surface information. The proposed registration algorithm is validated on synthesized datasets and 20 clinical datasets, through both qualitative and quantitative evaluations. Experimental results show that automatic registration can be successfully achieved between 3D B-mode US and CT images even with a large initial misalignment.

To assess the effect of ultrasound (US) fusion imaging on the clinical diagnostic and therapeutic strategies of focal liver lesions, which are difficult to detect or diagnose by conventional US. From November 2019 to June 2022, 71 patients with invisible or undiagnosed focal liver lesions who underwent fusion imaging combining US with CT or MR were included in this retrospective study. The reasons for US fusion imaging were as follows: (1) lesions that were undetectable or inconspicuous on B-mode US; (2) post-ablation lesions that could not be assessed accurately by B-mode US; (3) to evaluate whether the lesions detected by B-mode US that were consistent with those presented on MRI/CT images. Of the 71 cases, 43 cases were single lesions, and 28 cases were multiple lesions. Among the 46 cases which were invisible on conventional US, the display rate of lesions using US-CT/MRI fusion imaging was 30.8%, and that combined with CEUS was 76.9%. US-guided biopsy was performed in 30 patients after the detection and localization determined by fusion imaging, with a positive rate of 73.3%. Six patients with recurrence after ablation therapy were all detected and located accurately after fusion imaging, and 4 of them successfully underwent ablation therapy again. Fusion imaging contributes to the understanding of the anatomical relationship between lesion location and blood vessels. Additionally, fusion imaging can improve the diagnostic confidence, be helpful to guide interventional operations, and hence be conducive to clinical therapeutic strategies.

Ovarian cancer

Clinical utility of real-time ultrasound-multimodality fusion guidance for percutaneous biopsy of focal liver lesions

This study was performed to prospectively investigate the impact of image fusion in resolving discrepant findings between fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) or X-ray computed tomography (CT) in patients with gynaecological cancers. Discrepant findings were defined as lesions where the difference between the FDG-PET and MRI/CT images was assigned a value of at least 2 on a 5-point probability scale. The FDG-PET and MRI/CT images were taken within 1 month of each other. Image fusion between FDG-PET and CT was performed by automatic registration between the two images. During an 18-month period, 34 malignant lesions and seven benign lesions from 32 patients who had undergone either surgical excision or a CT-guided histopathological investigation were included for analysis. Among these cases, image fusion was most frequently required to determine the nature and/or the extent of abdominal and pelvic lesions (28/41, 68%), especially as regards peritoneal seeding (8/41, 20%). Image fusion was most useful in providing better localisation for biopsy (16/41, 39%) and in discriminating between lesions with pathological versus physiological FDG uptake (12/41, 29%). Image fusion changed the original diagnosis based on MRI/CT alone in 9/41 lesions (22%), and the original diagnosis based on FDG-PET alone in 5/41 lesions (12%). It led to alteration of treatment planning (surgery or radiotherapy) in seven of the 32 patients (22%). In patients with gynaecological cancers, the technique of image fusion is helpful in discriminating the nature of FDG-avid lesions, in effectively localising lesions for CT-guided biopsy and in providing better surgical or radiotherapy planning.

LB0009 EULAR recommendations for the use of imaging in large vessel vasculitis in clinical practice: 2023 update

In conventional thyroid diagnostics, the topographical correlation between thyroid nodules (TN) depicted on ultrasound (US) in axial or sagittal orientation and coronally displayed scintigraphy images can be challenging. Sensor-navigated I-124-PET/US fusion imaging has been introduced as a problem-solving tool for ambiguous cases. The purpose of this study was to investigate the results of multiple unexperienced medical students (MS) versus multiple nuclear medicine physicians (MD) regarding the overvalue of I-124-PET/US in comparison to conventional diagnostics (CD) for the functional assessment of TN. Methods: Out of clinical routine, cases with ambiguous findings on CD were selected for I-124-PET/US fusion imaging. Sixty-eight digital patient case files (PCF) of 34 patients (CDonly and CD+PET/US PCF) comprising 66 TN were provided to be retrospectively evaluated by 70 MD and 70 MS, respectively. A total of 2174 ratings (32.9 per TN) were carried out: 555 ratings (8.4 per TN) for CDonly and 532 ratings (8.1 per TN) for CD+PET/US by each MD and MS. Results: Functional assessment revealed 8.5%/11.7% (n.s.) (16.4%/25.8% (p = 0.0002)), 41.8%/28.5% (p < 0.0001) (23.9%/17.9% (p = 0.0193)), 36.0%/30.5% (n.s.) (57.3%/53.9% (n.s.)), and 13.7%/29.4% (p < 0.0001) (2.4%/2.4% (n.s.)) hyperfunctioning, indifferent, hypofunctioning, and not rateable TNs for CDonly (CD+PET/US) and MD/MS, respectively. The respective rating confidence was indicated as absolute certain, quite certain, equivocal, uncertain, and not rateable in 11.7/3.4% (p < 0.0001) (44.9%/38.9% (p = 0.0541), 51.9%/26.7% (p < 0.0001) (46.2%/41.5% (n.s.)), 21.6%/29.0% (p = 0.0051) (6.2%/14.8% (p < 0.0001)), 1.1%/11.5% (p < 0.0001) (0.2%/2.3% (p = 0.0032)), and 13.7%/29.4% (p < 0.0001) (2.4%/2.4% (n.s.)) by MD/MS, respectively. There was a significant difference in the diversity of the observers’ functional assessment of TN (MD 0.84 vs. MS 1.02, p = 0.0006) and the respective confidence in functional assessment (MD 0.93 vs. MS 1.16, p < 0.0001) between MD and MS on CDonly, whereas CD+PET/US revealed weaker differences for both groups (MD 0.48 vs. MS 0.47, p = 0.57; and MD 0.66 vs. MS 0.83, p = 0.0437). With the additional application of I-124-PET/US, the rating diversity of both MD and MS markedly tends towards more consistency (p < 0.0001 in each case). Conclusion: The additional application of sensor-navigated I-124-PET/US fusion imaging significantly influenced the functional assessment of TN positively, especially for unexperienced observers.

To investigate the value of I-124 positron emission tomography (PET) / ultrasound (US) fusion imaging in comparison to conventional diagnostics (CD) of Thyroid nodules (TN) by multiple observers. Digital patient case files (PCF) of patients that received CD and I-124-PET/US in clinical routine were prepared containing cine-loops of the examinations. All physicians with nuclear medicine specialty from Germany, Austria, and Switzerland were invited to participate. 106 acquired observers completed 7.2 ± 1.8 (median: 8, range: 4-14) randomly assigned PCF (CD only or CD+PET/US). They assessed the TN function, stated their confidence in functional assessment, and suggested a treatment course for each TN. 68 PCF of 34 patients comprising 66 TN ≥ 1 cm (= 1.94 TN/patient) were created. A total of 748 (11.2/TN), and 751 ratings (11.4/TN) were recorded for CD only, and CD+PET/US, respectively. The functional assessment revealed more hyper- or hypofunctioning (524 vs. 320, p < 0.0001) and less indifferent or not rateable (209 vs. 428, p < 0.0001) TN in CD+PET/US vs. CD only. The observers' confidence infunctional assessment was superior in CD+PET/US (p < 0.0001). Furthermore, the ratings were carried out more homogeneous in CD+PET/US (p < 0.0001). Fewer suggestion of follow up (p < 0.0001), and more (p < 0.0001) suggestion of invasive treatments (fine-needle aspiration & surgery) was observed in CD+PET/US. Radioiodine therapy was more often (p = 0.0036), and thyroid medication less often (p = 0.0167) advised in CD+PET/US. Functional assessment of equivocal TN shows frequent failures in CD, underestimating the incidence of hyper- and hypofunctioning lesions. Confidence in functional assessment significantly increases with additional PET/US. This influences the proposed treatment course.

X-ray computed tomography (CT) imaging plays an essential role in disease diagnosis due to its noninvasive, painless mode and superior penetration depth. However, the resolution of the soft tissue ...

To apply a meta-analysis to compare the utility of computed tomography (CT), ultrasonography (US), and magnetic resonance (MR) imaging in staging endometrial cancer. Data were obtained from a MEDLINE literature search and from manual reviews of article bibliographies. Articles were selected that included results in patients with proved endometrial cancer and imaging-histopathologic correlation and that presented data that allowed calculation of contingency tables. Data for the imaging evaluation of myometrial and cervical invasion were abstracted independently by two authors. Data on year of publication, International Federation of Gynecology and Obstetrics (FIGO) stage distribution, and methodologic quality were also collected. A subgroup analysis was performed to compare contrast medium-enhanced MR imaging with nonenhanced MR imaging, US, and CT. Six studies met the inclusion criteria for CT; 16, for US; and 25, for MR imaging. Summary receiver operating characteristic analysis showed no significant differences in the overall performance of CT, US, and MR imaging. In the assessment of myometrial invasion, however, contrast-enhanced MR imaging performed significantly better than did nonenhanced MR imaging or US (P < .002) and demonstrated a trend toward better results, as compared with CT. The lack of data on the assessment of cervical invasion at CT or US prevented meta-analytic comparison with data obtained at MR imaging. Results were not influenced by year of publication, FIGO stage distribution, or methodologic quality. Although US, CT, or MR imaging can be used in the pretreatment evaluation of endometrial cancer, contrast-enhanced MR imaging offers "one-stop" examination with the highest efficacy.

Objective To investigate the value of computed tomography (CT)-magnetic resonance imaging (MRI) image fusion in target volume delineation of postoperative precise radiotherapy for gliomas. Methods Thirty-six patients newly diagnosed with gliomas were enrolled and received postoperative intensity-modulated radiotherapy. Landmark (L) combined with manual fusion (M) and maximization of mutual information (MI) was used for image fusion. Target volume and organs at risk were delineated based on CT images and fused images, respectively. Comparison of the volume was made by pairwise t test. The distance from a landmark on CT image to the corresponding one on MRI image was calculated. The volume method and geometric center method were used to calculate the degree of volume overlap and changes in central positions after image fusion. Results The L+ M+ MI method achieved a high registration accuracy in image fusion, with a registration error less than 2 mm. In patients with grade Ⅲ-IV gliomas, the CT images yielded significantly smaller gross tumor volume (GTV) and clinical target volume (CTV) than the MRI images (74.62±46.91 vs. 105.99±58.86 cm3,P=0.042; 304.03±130.05 vs. 387.94±150.12 cm3,P=0.040). After image fusion, the smallest change in central position occurred in the chiasma (1.32±1.42 mm), and the largest change occurred in CTV (7.99±11.06 mm), followed by GTV and the brain stem. Conclusions CT-MRI image fusion helps to reduce the uncertainty of target volume delineation in patients with gliomas, especially in those with edema and residual tumor after surgery. Key words: Tomography, X-ray computed; Magnetic resonance imaging; Image fusion; Brain neoplasms/radiotherapy

What is the role of preoperative imaging for cochlear implants in adults with postlingual deafness?