Extended experience in the use of laparoscopic ultrasound to detect pelvic nodal metastasis in patients with cervical carcinoma

Terahertz imaging of metastatic lymph nodes using spectroscopic integration technique

Terahertz (THz) imaging was used to differentiate the metastatic states of frozen lymph nodes (LNs) by using spectroscopic integration technique (SIT). The metastatic states were classified into three groups: healthy LNs, completely metastatic LNs, and partially metastatic LNs, which were obtained from three mice without infection and six mice infected with murine melanoma cells for 30 days and 15 days, respectively. Under histological examination, the healthy LNs and completely metastatic LNs were found to have a homogeneous cellular structure but the partially metastatic LNs had interfaces of the melanoma and healthy tissue. THz signals between the experimental groups were not distinguished at room temperature due to high attenuation by water in the tissues. However, a signal gap between the healthy and completely metastatic LNs was detected at freezing temperature. The signal gap could be enhanced by using SIT that is a signal processing method dichotomizing the signal difference between the healthy cells and melanoma cells with their normalized spectral integration. This technique clearly imaged the interfaces in the partially metastatic LNs, which could not be achieved by existing methods using a peak point or spectral value. The image resolution was high enough to recognize a metastatic area of about 0.7 mm size in the partially metastatic LNs. Therefore, this pilot study demonstrated that THz imaging of the frozen specimen using SIT can be used to diagnose the metastatic state of LNs for clinical application.

Segmentation of Uterus Using Laparoscopic Ultrasound by an Image-Based Active Contour Approach for Guiding Gynecological Diagnosis and Surgery

In laparoscopic gynecologic surgery, ultrasound has been typically implemented to diagnose urological and gynecological conditions. We applied laparoscopic ultrasonography (using Esaote 7.5~10MHz laparoscopic transducer) on the retrospective analyses of 42 women subjects during laparoscopic extirpation and excision of gynecological tumors in our hospital from August 2011 to August 2013. The objective of our research is to develop robust segmentation technique for isolation and identification of the uterus from the ultrasound images, so as to assess, locate and guide in removing the lesions during laparoscopic operations. Our method enables segmentation of the uterus by the active contour algorithm. We evaluated 42 in-vivo laparoscopic images acquired from the 42 patients (age 39.1 ± 7.2 years old) and selected images pertaining to 4 cases of congenital uterine malformations and 2 cases of pelvic adhesions masses. These cases (n = 6) were used for our uterus segmentation experiments. Based on them, the active contour method was compared with the manual segmentation method by a medical expert using linear regression and the Bland-Altman analysis (used to measure the correlation and the agreement). Then, the Dice and Jaccard indices are computed for measuring the similarity of uterus segmented between computational and manual methods. Good correlation was achieved whereby 84%-92% results fall within the 95% confidence interval in the Student t-test) and we demonstrate that the proposed segmentation method of uterus using laparoscopic images is effective.

A novel ultrasound based approach for lesion segmentation and its applications in gynecological laparoscopic surgery

Laparoscopic ultrasound (LUS) has been widely utilized as a surgical aide in general, urological, and gynecological applications. Our study summarizes the clinical applications of laparoscopic ultrasonography in laparoscopic gynecologic surgery. Retrospective analyses were performed on 42 women subjects using laparoscopic surgery during laparoscopic extirpation and excision of gynecological tumors in our hospital from August 2011 to August 2013. Specifically, the Esaote 7.5 × 10 MHz laparoscopic transducer was used to detect small residual lesions, as well as to assess, locate and guide in removing the lesions during laparoscopic operations. The findings of LUS were compared with those of preoperative trans-vaginal ultrasound, postoperative, and pathohistological examinations. In addition, a novel method for lesion segmentation was proposed in order to facilitate the laparoscopic gynecologic surgery. In our experiment, laparoscopic operation was performed using a higher frequency and more close to pelvic organs via laparoscopic access. LUS facilitates the ability of gynaecologists to find small residual lesions under laparoscopic visualization and their accurate diagnosis. LUS also helps to locate residual lesions precisely and provides guidance for the removal of residual tumor and eliminate its recurrence effectively. Our experiment provides a safer and more valuable assistance for clinical applications in laparoscopic gynecological surgery that are superior to trans-abdominal ultrasound and trans-vaginal ultrasound.

Discrimination of metastatic from hyperplastic pelvic lymph nodes in patients with cervical cancer by diffusion-weighted magnetic resonance imaging

PURPOSE

To evaluate the diagnostic value of diffusion-weighted MR imaging for differentiating metastatic and hyperplastic pelvic lymph nodes in patients with cervical carcinoma.

MATERIALS AND METHODS

In this prospective study, 61 untreated patients were scanned with both morphological MR and diffusion-weighted imaging (DWI). Bilateral pelvic lymphadenectomy was then performed in all patients. Of the 1118 total dissected and histopathologically evaluated pelvic lymph nodes, 153 enlarged nodes with short-axis diameter larger than 5 mm were included for further study. The mean ADC values of all enlarged lymph nodes and the relative ADC values between tumors and nodes were also measured and, respectively, compared between the metastatic and hyperplastic node groups.

RESULTS

The mean ADC value of metastatic [(1.046 ± 0.198) × 10⁻³ mm²/s] nodes was significantly lower than that of hyperplastic [(1.289 ± 0.194) × 10⁻³ mm²/s] nodes (P < 0. 001). The relative ADC values between tumor and nodes were significantly lower in malignant [(0.19 ± 0.17) × 10⁻³ mm²/s] than hyperplastic [(0.4 ± 0.21) × 10⁻³ mm²/s] nodes (P < 0. 001). When a mean ADC value of 1.15 × 10⁻³ mm²/s was used as a threshold value for differentiating metastatic from hyperplastic nodes, the best results were obtained with a sensitivity of 83.3%, specificity of 74.7%, and accuracy of 78.4%.

CONCLUSION

DWI is useful in differentiating metastatic and hyperplastic pelvic lymph nodes in patients with cervical carcinoma.

The technique of laparoscopic pelvic ultrasonography for metastatic lymph node

Many reports have provided evidence to support the effective use of diagnostic laparoscopy and laparoscopic ultrasonography (LUS) to determine if patients with upper abdominal malignant diseases are operable so that unnecessary laparotomy can be avoided. LUS is less frequently applied to patients with pelvic malignancies and this is probably related to the technical difficulties. We have developed the LUS technique in examining the pelvic nodes for metastasis systematically and have applied it to 241 cervical cancer patients. The procedure is safe and not associated with any major morbidity. The mean duration of pelvic node assessment by LUS is 14 minutes and the procedure can be satisfactorily completed in 98% of patients. The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of LUS in detecting pelvic nodal metastasis were 81.2%, 55.6%, 88.4%, 57.7%, and 87.5%, respectively, in patients scheduled for radical hysterectomy. In this report, we describe the LUS technique in detail and demonstrate important landmarks that provide useful orientation during an LUS examination. The technical limitations and pitfalls are also discussed.

Clinical use of laparoscopic ultrasonography in detecting nodal metastasis in advanced-stage cervical carcinoma

OBJECTIVE

To assess the clinical use of a laparoscopic ultrasound scan (LUS) to identify pelvic and para-aortic node metastasis in patients with advanced-stage cervical cancer.

METHODS

After examination under general anesthesia and cystoscopy, LUS was used to examine the pelvic nodes of patients with advanced-stage cervical cancer. Abnormal nodes were excised before definitive treatment to confirm the nodal status. Patients without abnormal para-aortic nodes on preoperative computer tomography/magnetic resonance imaging in the past 3 years were surgically staged via laparoscopic extraperitoneal aortic node sampling, and the findings were correlated with LUS findings. The predictive values of abnormal pelvic nodes on LUS for pelvic and aortic node metastasis were determined.

RESULTS

A total of 119 advanced-stage cervical cancer patients underwent LUS of pelvic nodes. Abnormal pelvic nodes were found in 62 (52.1%) patients, and metastasis was confirmed by histology in 38 (31.9%) patients. Three patients had micro-metastasis in para-aortic nodes, and all of these patients had abnormal pelvic lymph nodes on LUS.

CONCLUSION

Abnormal pelvic nodes are commonly found on LUS in patients with advanced-stage cervical cancer, and selective excision biopsy is needed to confirm pelvic node metastasis. Surgical staging of aortic nodes might be considered for patients with abnormal pelvic nodes on LUS.

Prediction of lymph node metastases in vulvar cancer: a review

The aim of this study was to review the literature on currently available non- and minimally-invasive diagnostic methods and analysis of primary tumor characteristics for prediction of inguinofemoral lymph node metastases in patients with primary squamous cell carcinoma of the vulva. We used the English language literature in PubMed and reference lists from selected articles. Search terms included vulvar carcinoma, prognosis, lymph node metastases, ultrasound, computer tomography, magnetic resonance imaging, positron emission tomography, and sentinel lymph node. No study type restrictions were imposed. Currently no noninvasive imaging techniques exist that are able to predict lymph node metastases with a high enough negative predictive value. A depth of invasion < or =1 mm is the only histopathologic parameter that can exclude patients for complete inguinofemoral lymphadenectomy. No other clinicopathologic parameter allows exclusion of lymph node metastases with a high enough negative predictive value. The minimally invasive sentinel node procedure is a promising technique for selecting patients for complete lymphadenectomy, but its safety has not been proven yet.