Real-time ultrasound virtual navigation in 3D PET/CT volumes for superficial lymph-node evaluation: innovative fusion examination

OBJECTIVE

To evaluate the feasibility and clinical application of fusion imaging with virtual navigation, combining ¹⁸ F-fluorodeoxyglucose (¹⁸ F-FDG) positron emission tomography/computed tomography (PET/CT) with real-time ultrasound imaging, in assessing superficial lymph nodes in breast-cancer and gynecological-cancer patients.

METHODS

This was a pilot study of breast- and gynecological-cancer patients with abnormal uptake of ¹⁸ F-FDG by axillary or groin lymph nodes on PET/CT scan, examined at our institution between January 2017 and May 2019. Fusion imaging was performed, uploading preacquired PET/CT DICOM images onto the ultrasound machine and synchronizing them with real-time ultrasound scanning performed at the lymph-node site. In the first phase, we assessed the feasibility and reliability of fusion imaging in a series of 10 patients with suspicious lymph nodes on both PET/CT and ultrasound, and with full correspondence between both techniques in terms of size, shape and morphology of the lymph nodes (Group A). In the second phase, we included 20 patients with non-corresponding findings between PET/CT and ultrasound: 10 patients with lymph nodes that were suspicious or pathological on PET/CT scan but not suspicious on ultrasound assessment (Group B), and 10 patients with suspicious or pathological lymph nodes on both PET/CT and ultrasound but with no correspondence between the two techniques in terms of number of affected lymph nodes (Group C).

RESULTS

In the 30 selected patients, fusion imaging was assessed at 30 lymph-node sites (22 inguinal and eight axillary nodes). In the first phase (Group A), the fusion technique was shown to be feasible in all 10 lymph-node sites evaluated. In the second phase, fusion imaging was completed successfully in nine of 10 cases in Group B and in all 10 cases in Group C. In all groups, fusion imaging was able to identify the target lymph node, guiding the examiner to perform a core-needle aspiration biopsy or to inject radiotracer for selective surgical nodal excision, according to the radio-guided occult lesion localization technique.

CONCLUSION

Fusion imaging with virtual navigation, combining PET/CT and real-time ultrasound imaging, is technically feasible and able to detect target lymph nodes even when PET/CT and ultrasound findings are inconsistent. Fusion imaging can also be used to guide the performance of core-needle aspiration biopsy, avoiding further surgical diagnostic procedures, or the injection of radiotracer for selective surgical nodal excision, enabling more sparing, selective surgery. This innovative technique could open up multiple diagnostic and therapeutic opportunities in breast and gynecological oncology. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Imaging in gynecological disease (13): clinical and ultrasound characteristics of endometrioid ovarian cancer

OBJECTIVE

To describe the clinical and ultrasound characteristics of ovarian pure endometrioid carcinomas.

METHODS

This was a retrospective multicenter study of patients with a histological diagnosis of pure endometrioid carcinoma. We identified 161 patients from the International Ovarian Tumor Analysis (IOTA) database who had undergone preoperative ultrasound examination by an experienced ultrasound examiner between 1999 and 2016, and another 78 patients from the databases of the departments of gynecological oncology in the participating centers. All tumors were described using IOTA terminology. In addition, one author reviewed all available ultrasound images and described them using pattern recognition.

RESULTS

Median age of the 239 patients was 55 years (range, 19-88 years). On ultrasound examination, two (0.8%) endometrioid carcinomas were described as unilocular cysts, three (1.3%) as multilocular cysts, 37 (15.5%) as unilocular-solid cysts, 115 (48.1%) as multilocular-solid cysts and 82 (34.3%) as solid masses. Median largest tumor diameter was 102.5 mm (range, 20-300 mm) and median largest diameter of the largest solid component was 63 mm (range, 9-300 mm). Papillary projections were present in 70 (29.3%) masses. Most cancers (188 (78.7%)) were unilateral. In 49 (20.5%) cases, the cancer was judged by the pathologist to develop from endometriosis. These cancers, compared with those without evidence of tumor developing from endometriosis, more often manifested papillary projections on ultrasound (46.9% (23/49) vs 24.7% (47/190)), were less often bilateral (8.2% (4/49) vs 24.7% (47/190)) and less often associated with ascites (6.1% (3/49) vs 28.4% (54/190)) and fluid in the pouch of Douglas (24.5% (12/49) vs 48.9% (93/190)). Retrospective analysis of available ultrasound images using pattern recognition revealed that many tumors without evidence of tumor developing from endometriosis (36.3% (41/113)) had a large central solid component entrapped within locules, giving the tumor a cockade-like appearance.

CONCLUSIONS

Endometrioid cancers are usually large, unilateral, multilocular-solid or solid tumors. The ultrasound characteristics of endometrioid carcinomas developing from endometriosis differ from those without evidence of tumor developing from endometriosis, the former being more often unilateral cysts with papillary projections and no ascites. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Pharmacological control of the mevalonate pathway: effect on arterial smooth muscle cell proliferation

The mevalonate (MVA) pathway is involved in cell proliferation. We investigated drugs acting at different enzymatic steps on rat aorta smooth muscle cell (SMC) proliferation. Competitive inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (0.1-10 microM) dose-dependently decreased (up to 90%) SMC proliferation. This effect was prevented by 100 microM MVA, 10 microM all-trans farnesol (F-OH) and 5 microM all-trans geranylgeraniol (GG-OH), precursors of protein prenyl groups, but not by 2-cis GG-OH, precursor of dolichols, squalene and ubiquinone. The same inhibitory effect was obtained with 6-fluoromevalonate (1-50 microM), an inhibitor of MVA-pyrophosphate decarboxylase. Partial recovery of cell proliferation was possible by all-trans F-OH and all-trans GG-OH, but not MVA. Squalestatin 1 (1-25 microM), a potent squalene synthase inhibitor, blocked cholesterol synthesis and slightly inhibited (21% decrease) SMC proliferation only at the highest tested concentration. NB-598 (1-10 microM), a potent squalene epoxidase inhibitor, blocked cholesterol synthesis without affecting SMC proliferation. Finally, the benzodiazepine peptidomimetic BZA-5B (10-100 microM), a specific inhibitor of protein farnesyltransferase, time- and dose-dependently decreased SMC proliferation (up to 62%) after 9 days. This effect of BZA-5B was prevented by MVA and all-trans GG-OH, but not by all-trans F-OH. SMC proliferation was not affected by the closely related compound BZA-7B, which does not inhibit protein farnesyltransferase. Altogether, these findings focus the role of the MVA pathway in cell proliferation and call attention to the involvement of specific isoprenoid metabolites, probably through farnesylated and geranylgeranylated proteins, in the control of this cellular event.

Effects of 26-aminocholesterol, 27-hydroxycholesterol, and 25-hydroxycholesterol on proliferation and cholesterol homeostasis in arterial myocytes

The major relation existing between cell growth and cholesterol homeostasis prompted us to investigate the effect of 26-aminocholesterol (26-NH2), 27-hydroxycholesterol (27-OH), and 25-hydroxycholesterol (25-OH) on these cellular events. To test this relation, we incubated human and rat arterial myocytes with the sterols for 72 hours. All the tested compounds (0.5 to 7.5 mumol/L) inhibited rat and human myocyte proliferation and cholesterol biosynthesis in a dose-dependent manner. 26-NH2 was more potent than oxysterols in inhibiting human myocyte proliferation but equieffective in rat cells; 27-OH and 25-OH displayed similar activity in both cell lines. Inhibition of nuclear incorporation of thymidine in rat myocytes is consistent with decreased cell count. The antiproliferative effect of the tested sterols was reversible. The high inhibition (80%) of cholesterol biosynthesis necessary to induce a decrease in myocyte proliferation suggests a causal relation between the cholesterol synthetic pathway and these cellular processes. In addition, all the tested sterols were able to inhibit hydroxymethyl glutaryl-coenzyme A reductase activity in intact myocytes but not in cell-free extracts. The finding that 26-NH2 but not 27-OH or 25-OH does not suppress LDL receptor activity in either human or rat myocytes supports the achievement of selectivity over the coordinately regulated LDL receptor gene. The ability of 26-NH2 to interfere with myocyte proliferation and cholesterol synthesis without affecting the LDL receptor pathway confers at least in vitro a pharmacological interest on the compound in the process of atherogenesis.