**2. Materials and Methods**

We enrolled 81 consecutive women diagnosed with cervical cancer by clinical examination and referred to the European Institute of Oncology from November 2012 to January 2021. All patients underwent diagnostic evaluation, including a cervical biopsy or a pathological review of the original slides if the initial diagnosis was made at a different institution. All tumors were staged according to the FIGO (2018) criteria using vaginal and rectal examinations, standard chest and abdominal computed tomography (CT), TVUS or TRUS, and MRI. Twenty-five patients were excluded either because they received nonsurgical treatments [12] or their FIGO stage was above IB2 [13]. Data from 56 patients were analyzed in the study. We included only the patients that underwent both VGS and MRI, whose surgical specimen was available within 30 days from the imaging evaluation, and that had early FIGO stages (≤IB2).

The results of MRI and VGS were compared with the pathology report. If the MRI scan was performed outside the European Institute of Oncology, an internal gynecological oncology radiologist reviewed the images.

All patients underwent both TVUS and VGS. The scans were performed by two experienced ultrasound examiners with 25 and 15 years of experience in ultrasound for gynecologic oncology (D.F. and A.M.V.U.), respectively. The examiners were blinded to the MRI results.

All women were examined in the lithotomy position with an empty bladder using high-end ultrasound equipment, with the frequency of the vaginal probes varying between 5.0 and 9.0 MHz. Ultrasonographic images were acquired according to a standardized time gray-scale examination technique.

The VGS procedure consists of four steps: (1) a 5.3 Fr sonohysterography catheter is inserted into the vagina by an assistant; then, (2) the probe is inserted by the operator; (3) the assistant closes the vaginal channel by narrowing the major labia; (4) approximately 60 cc of room temperature saline solution is instilled while the ultrasound is performed.

The following parameters were evaluated by VGS and TVUS: tumor presence, maximum diameter of the tumor, parametrial and fornix infiltration, vaginal involvement, stromal invasion, anterior and posterior septum involvement, and blood flow of the lesion. The blood flow was assessed by a color Doppler score based on the intensity of the color signal with the following value ranges: (1) no flow, (2) minimal flow, (3) moderate flow, and (4) high vascular flow.

A dedicated pathologist, highly experienced in gynecologic cancers, assessed the specimens and described the size and extent of the tumor, histology type, grading, stromal invasion, minimum free thickness, and maximum deep infiltration.

Approval was obtained from the ethics committee of the European Institute of Oncology (UID 2731), and all patients signed an informed consent form.
