Keypoints
-
MRI of endometrial and cervical cancer facilitates patient stratification into treatment groups.
-
MRI acquisition and interpretation errors can lead to diagnostic and staging mistakes.
-
In endometrial and cervical cancer, DWI, and DCE improve staging accuracy and tumor delineation.
-
For both endometrial and cervical cancer, assessing lymph node involvement plays an important role. Compared to CT and MRI, 18fluorine-18 fluorodeoxyglucose PET-CT (18F-FDG PET-CT) is more accurate for the detection of nodal metastasis larger than 10 mm.
Introduction
Endometrial cancer
Cervical cancer
Role of MRI in endometrial and cervical cancers
Detecting and staging endometrial cancer
TNM | FIGO | Description |
---|---|---|
Tx | Primary tumor cannot be assessed | |
T0 | No evidence of primary tumor | |
T1 | Ia | Tumor confined to the corpus uteria |
T1a | IAa | Tumor limited to the endometrium or invading less than half of the myometrium |
T1b | IB | Tumor invades one half or more of the myometrium |
T2 | II | Tumor invades cervical stroma, but does not extend beyond the uterus |
T3 | III | Local and/or regional spread |
T3a | IIIa | Tumor invades the serosa of the corpus uteri or adnexa (direct extension or metastasis) |
T3b | IIIb | Vaginal or parametrial involvement (direct extension or metastasis) |
N1, N2 | IIIC | Metastasis to pelvic or paraaortic lymph nodesb |
N1 | IIIC1 | Metastasis to pelvic lymph nodes |
N2 | IIIC2 | Metastasis to paraaortic lymph nodes with/without metastasis to pelvic lymph nodes |
T4c | IVA | Tumor invades bladder/bowel mucosa |
M1 | IVB | Distant metastasis (excluding metastasis to vagina, pelvic serosa, or adnexa) (including metastasis to inguinal lymph nodes, intra-abdominal lymph nodes other than paraaortic or pelvic nodes) |
Detecting and staging cervical cancer
TNM | FIGO | Description |
---|---|---|
Tx | Primary tumor cannot be assessed | |
T0 | No evidence of primary tumor | |
Tis | Preinvasive carcinoma | |
T1 | I | The carcinoma is strictly confined to the cervix (extension to the uterine corpus should be disregarded) |
T1a | IA | Invasive carcinoma that can be diagnosed only by microscopy, with maximum depth of invasion < 5 mma |
T1a1 | IA1 | Measured stromal invasion depth of < 3 mm |
T1a2 | IA2 | Measured stromal invasion depth ≥ 3 mm and < 5 mm |
T1b | IB | Invasive carcinoma with measured deepest invasion of ≥ 5 mm (greater than Stage IA), lesion limited to the cervix uterib |
T1b1 | IB1 | Invasive carcinoma with measured deepest stromal invasion of ≥ 5 mm, and greatest dimension of < 2 cm |
T1b2 | IB2 | Invasive carcinoma with greatest dimension of ≥ 2 cm and < 4 cm |
- | IB3d | Invasive carcinoma with greatest dimension of > 4 cm |
T2 | II | The carcinoma invades beyond the uterus, but has not extended into the lower third of the vagina or to the pelvic wall |
T2a | IIA | Involvement limited to the upper two-thirds of the vagina without parametrial invasion |
T2a1 | IIA1 | Invasive carcinoma with greatest dimension of < 4 cm |
T2a2 | IIA2 | Invasive carcinoma with greatest dimension of ≥ 4 cm |
T2b | IIB | With parametrial involvement but not up to the pelvic wall |
T3 | III | The carcinoma involves the lower third of the vagina and/or extends to the pelvic wall and/or causes hydronephrosis or nonfunctioning kidney and/or involves pelvic and/or para-aortic lymph nodesc |
T3a | IIIA | The carcinoma involves the lower third of the vagina, with no extension to the pelvic wall |
T3b | IIIB | Extension to the pelvic wall and/or hydronephrosis or nonfunctioning kidney (unless known to be due to another cause) |
Nd | IIICd | Involvement of pelvic and/or para-aortic lymph nodes, irrespective of tumor size and extent (with r and p notations)c |
IIIC1d | Pelvic lymph node metastasis only | |
IIIC2d | Para-aortic lymph nodes metastasis | |
T4 | IV | The carcinoma has extended beyond the true pelvis or has involved (biopsy proven) the mucosa of the bladder or rectum (the presence of bullous edema is not sufficient to classify a case as Stage IV) |
IVA | Spread to adjacent pelvic organs | |
M1 | IVB | Spread to distant organs |
Microinvasive cervical cancer (FIGO IA)
Invasive cervical carcinoma (FIGO stages IB1, IB2, and IIA1)
Locally advanced CC (FIGO stages IB3, IIA2, IIB, III, and IVA)
FIGO stage IVB/distant metastasis
MRI technique for endometrial and cervical cancers
Sequence | Axial T1 | Sagittal T2 | Sagittal DWI | Coronal T2 | Axial T2$ | Axial DWI | Axial DCE | Sagittal DCE | Axial T2 | Coronal T2 |
---|---|---|---|---|---|---|---|---|---|---|
Sequence | TSE | TSE | EPI | TSE | TSE | EPI | FS 3D GRE T1% | 3D FS GRE T1 | SS-FSE& | SS-FSE& |
TE (ms) | 8 | 100 | 90 | 100 | 100 | 81 | 2.3 | 2.3 | 70 | 70 |
TR (ms) | 550 | 4000 | 4000 | 4000 | 4000 | 6000 | 4.5 | 3.6 | 1000 | 1000 |
Echo train length | 4 | 17 | EPI | 17 | 17 | EPI | – | – | 55 | 55 |
Flip angle (degrees) | 90 | 90 | 90 | 90 | 90 | 90 | 10 | 10 | 90 | 90 |
FOV (mm) | 320 | 200 | 320 | 200 | 200 | 200 | 300 | 300 | 350 | 320 |
Slice Thickness (mm) | 5 | 3 | 3 | 3 | 3 | 3 | 1.75 | 1.4 | 5 | 5 |
Gap (mm) | 0.5 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | – | – | 0.5 | 0.5 |
NEX | 1 | 2 | 2 | 2 | 2 | 1/2/8/12 | 1 | 2 | 1 | 1 |
Matrix size | 0.8 × 1 | 0.6 × 0.7 | 3 × 3 | 0.6 × 0.7 | 0.6 × 0.7 | 2.6 × 3 | 1.9 × 1.9 | 1.5 × 1.8 | 1.4 × 1.6 | 1.4 × 1.6 |
b values (s/mm2) | 0, 800 | 0, 500, 800, 1000 |
Artifacts | Pitfall | Pearl |
---|---|---|
Motion artifacts Peristalsis (bladder, bowel) | Limit visualization of the anatomical detail of the uterus | • Adequate patient preparation • Use antiperistalsis agents |
Sequence-specific artifacts while using rapid parallel imaging techniques such as ASSET (GE units) and SENSE (Phillips units), mSENSE (Siemens units) | May make image interpretation difficult | • Increase FOV |
Metal artifacts - Hip prosthesis - Surgical clips | Limit visualization of the anatomical detail of the uterus and pelvic structures Makes staging more difficult | • Use MARS sequences |
Patient preparation
T2-weighted imaging
Functional imaging
Functional imaging in disease prognosis and treatment response monitoring
Functional imaging in follow-up and detection of recurrent disease
MRI pitfalls in endometrial cancer
Staging pitfalls
Detection and myometrial invasion (stage IA/IB)
Staging (FIGO) | Pitfall | Pearl |
---|---|---|
1. STAGE IA/IB: detection and myometrial invasion • Small or isointense tumors • Poor visualization of endometrium and/or poor tumor-to-myometrium interface: - Presence of leiomyomas/adenomyosis - Thin myometrium: postmenopause, cornual regions, or secondary to a compressive large endometrial mass | No detection Underestimation or overestimation of myometrial invasion depth | - DCE and DWI improve detection of small and isointense tumors - DWI improves tumor detection and delineation - In DCE imaging, the presence of a contiguous band of subendometrial enhancement excludes myometrial invasion |
2. STAGE II: cervical invasion Tumor protruding or distending cervical os | Misdiagnosis of cervical invasion | - Cervical stroma disruption is necessary for diagnosis of cervical stromal invasion - DWI and DCE improve tumor delineation |
3. STAGE IIIA • Coexistent ovarian and endometrial tumor | Misinterpreting stage IIIA as synchronous cancer and vice versa | - Synchronous ovarian and endometrial cancer • Uterus: early-stage endometrial cancer with minimal or no myometrial invasion • Ovary: unilateral large mass in the background of endometriosis or borderline tumor - Ovarian metastasis (IIIA) • Uterus: deep myometrial invasion and/or tubal invasion • Ovary: smaller mass, bilateral ovarian involvement |
4. STAGE IV Tumor invades bladder/bowel mucosa | The presence of bladder mucosal edema (bullous edema) is not indicative of mucosal invasion | - Change the direction of phase and frequency - A preserved fat plane between the tumor and bladder or rectum excludes stage IVA - DWI (DWI+T2WI) and DCE help in tumor delineation |
Cervical invasion (stage II)
Adnexal or ovarian metastases (stage IIIA)
Vaginal metastasis (stage IIIB)
Bladder and bowel mucosa involvement (stage IVA)
Distant metastases (stage IVB)
Recurrence of endometrial cancer
Mimickers of endometrial cancer on MRI
Benign mimickers
Malignant mimickers
MRI pitfalls in cervical cancer
Staging pitfalls
Early tumors (stages IA–IB1)
Staging (FIGO) | Pitfall | Pearl |
---|---|---|
1. STAGE IA, IB1 (< 2 cm) • Very small (< 1 cm) tumors • Isointense tumors in young women | No detection | • DWI and DCE improve detection and delineation of small tumors |
2. STAGE IB3 • Cervical edema and/or inflammation secondary to a recent biopsy or to cervical/vaginal compression by a large tumor (> 4 cm)a | Overstaging IB3 as stage IIA in large and exophytic tumors Overstaging as FIGO IIB tumor (parametrial invasion) | • Use vaginal gel to distend vaginal walls • DWI and DCE improve the accuracy of T2WI for the evaluation of parametrial invasion Ancillary findings for parametrial invasion: • Irregular interface between tumor and parametrium • Asymmetric tumoral bulge • Vascular encasement |
3. Stage IIB • Diffuse T2 signal inhomogeneity of the cervical rim due to complete tumoral invasion, without an evident parametrial mass | Understaging IIB as IB2–IB3 tumors | • Full-thickness cervical stromal replacement by cancerous tissue may be the only feature associated with parametrial invasion • The cervical rim must be thick (> 3 mm) and homogeneous on T2WI to exclude parametrial invasion |
4. STAGE III • IIIB • IIIC | Misinterpreting a benign hydronephrosis as malignant ureteral infiltration Misinterpreting benign adenopathies as malignant lymphatic spread Misinterpreting malignant adenopathies as other pelvic masses (ovaries …) | • Review clinical data and symptoms, and use other techniques (i.e., ultrasound, CT urography, or large-FOV MRI). • Review clinical data and symptoms and perform node aspiration or biopsy whenever possible • Knowledge of pelvic fascia, peritoneal-extraperitoneal spaces, and other pelvic structures is critical |
5. STAGE IV Same as in endometrial cancer (see Table 5) |