Benha Medical Journal

REVIEW ARTICLE
Year
: 2016  |  Volume : 33  |  Issue : 1  |  Page : 10--13

Role of MRI diffusion in the diagnosis of uterine cervical carcinoma


Eman Samy, Hamada Khater, Medhat M Refaat 
 Department of Radiology, Benha University, Benha City, El Kalyobya, Egypt

Correspondence Address:
Eman Samy
Assistant Lecturer at Radiology Department, Atlam Street, El Haras El Watany, Benha, El Kalyobya
Egypt

Abstract

Diffusion-weighted imaging is a potentially useful adjunct to conventional MRI in the evaluation of gynecologic tumors, thus improving the overall diagnostic accuracy, tumor staging, prediction of response to therapy, and treatment follow-up.



How to cite this article:
Samy E, Khater H, Refaat MM. Role of MRI diffusion in the diagnosis of uterine cervical carcinoma.Benha Med J 2016;33:10-13


How to cite this URL:
Samy E, Khater H, Refaat MM. Role of MRI diffusion in the diagnosis of uterine cervical carcinoma. Benha Med J [serial online] 2016 [cited 2019 Dec 13 ];33:10-13
Available from: http://www.bmfj.eg.net/text.asp?2016/33/1/10/194381


Full Text



 Introduction



Cervical cancer is the third most common malignancy in women worldwide. The frequency varies considerably between developed and developing countries, with cervical cancer being the second most common cancer in developing countries [1].

Conventional MRI has an established role in gynecologic imaging. However, increasing clinical demand for improved lesion characterization and disease mapping to optimize patient management has resulted in the incorporation of newer sequences, such as diffusion-weighted imaging (DWI) [2].

DWI is a potentially useful adjunct to conventional MRI in the evaluation of gynecologic tumors, thus improving the overall diagnostic accuracy, tumor staging, prediction of response to therapy, and treatment follow-up [3].

In cervical carcinoma, in the vast majority of cases the diagnosis is known before the patient arrives in the MRI suite. The critical clinical question we are asked to address is the stage of the disease, particularly when the tumor involves the parametrium. The clinician can assess the degree of vaginal involvement. Treatment options depend on our morphologic assessment of the cervical cancer, with the critical management decisions based on the size of the mass and the presence of parametrial (stage 2B) disease. We must carefully assess the stromal ring of the cervix, and our ability to include or exclude parametrial involvement will determine whether the patient will undergo a hysterectomy or chemotherapy–radiation therapy as the first line of therapy [4].

The value of DWI lies on the localization of pelvic lymphadenopathy. Certainly, we know that lymph node size is a poor predictor of metastatic disease, and a modality that could help discriminate between malignant and nonmalignant lymph nodes would be very beneficial in staging. As stated by Sumi et al., DWI shows promise in differentiating lymphoma from carcinoma [5].

High-quality diffusion-weighted MRI of the entire pelvis can now be performed as part of a gynecologic examination without greatly increasing total imaging time. Diffusion-weighted MRI provides important new information noninvasively. This unique modality is helpful in the initial staging of known malignancies, differentiating benign from malignant lesions, assessing treatment response, and determining the presence of disease recurrence [6]. To ensure accuracy, it is important to be aware of the potential pitfalls of diffusion-weighted MRI and to review findings in conjunction with findings obtained with anatomic sequences. Increasing familiarity with apparent diffusion coefficient (ADC) calculation and manipulation software, including the ability to fuse anatomic and diffusion data, will allow radiologists to gain confidence and thus to provide new information to physicians who are caring for women with known or suspected gynecologic malignancies [7].

Application of MRI diffusion-weighted imaging on cervical cancer

Staging

European Society of Urogenital Radiology and American College of Radiology guidelines [8] call for MRI for staging clinical stage IB1 tumors and beyond, and smaller tumors if trachelectomy is planned. On T1-weighted images, cervical carcinomas are usually isointense to normal cervix and may not be visible. On T2-weighted images, cervical cancer appears as a mass of intermediate signal intensity disrupting the low-signal-intensity cervical stroma. The sagittal plane allows evaluation of tumor extension into the lower uterine segment, vagina, and the anterior and posterior fat planes. The oblique axial T2-weighted image perpendicular to the long axis of the cervix is important for assessing parametrial invasion [9]. Preservation of the low-signal-intensity fibrous cervical stroma, no matter how thin, virtually excludes parametrial invasion.

On dynamic contrast-enhanced MRI, small tumors are homogeneously enhancing, and enhancement occurs earlier than that in the normal cervical stroma, thus facilitating tumor detection. Large tumors are frequently necrotic but are often surrounded by an enhancing rim that facilitates tumor delineation [10]. Although the addition of contrast-enhanced sequences may improve reader confidence in tumor detection, the use of contrast enhancement has not been found to improve overall staging accuracy compared with T2-weighted imaging alone [11]. Several studies have shown that the mean ADC value of cervical carcinoma is significantly lower than that of normal cervical tissue [12]. In cervical cancer staging, DWI findings may be clinically relevant in the following two scenarios: isointense tumors, such as diffusely infiltrative adenocarcinomas in young women, and early cervical cancer for exact delineation of tumor margins if fertility-preserving surgery is planned [13]. Those authors evaluated 20 patients with confirmed cervical intraepithelial neoplasia and 18 with stage Ib1 cervical tumors and found that tumoral ADC values were lower than the values in nontumoral areas.

Response evaluation

DWI findings have been considered as a biomarker of cervical tumor treatment response. An increase in ADC was described after 2 weeks of therapy before size changes occurred and was indicative of response. This technique has the potential for allowing early monitoring of the response to chemoradiotherapy.

Tumor recurrence

There is no consensus as regards routine imaging follow-up after radical hysterectomy. Imaging is undertaken only if indicated by clinical symptoms. Changes after radiotherapy and surgery can result in areas of fibrosis or cystic change that can be difficult to differentiate from recurrence [14]. During the early post-treatment period (after the first cycle of chemotherapy), the specificity of PET/CT may be reduced because of the frequently indistinguishable morphologic features and intense radiotracer uptake in both inflammatory tissue and the tumor. DWI can be helpful for this indication ([Figure 1]). High ADC values are more likely to represent areas of edema or inflammation, and low ADC values are suggestive of the presence of active tumor cells.{Figure 1}

Retained mucus in the cervix may exhibit the T2 shine-through effect. Moreover, after cone biopsy, the area biopsied exhibits restricted diffusion due to blood products. Finally, both the desmoplastic reaction due to radiotherapeutic changes and residual tumor have low ADC values. The desmoplastic reaction, however, does not have high signal intensity on b1000 images.

Cystic lesions of the cervix: differentiation of benign from malignant cystic lesions

Adenoma malignum is a rare form of mucinous adenocarcinoma of the cervix with a specific clinical presentation. Presenting symptoms include a watery vaginal discharge and association with Peutz–Jeghers syndrome, or mucinous tumor of the ovary. At MRI, adenoma malignum appears as a hyperintense cervical lesion on T2-weighted images and is characterized by multiple grape-like cystic clusters extending from the endocervical glands to the deep cervical stroma [15]. An enhancing component is typically present. On DWI, the solid component is easily detected as an area of high signal intensity on the high-b-value image with corresponding restriction on the ADC map ([Figure 2]). The imaging findings guide deep cervical biopsy because adenoma malignum cannot be diagnosed during a routine Pap test [16]. The main benign differential diagnosis of adenoma malignum is tunnel clusters, which are a specific subtype of nabothian cyst characterized by complex multicystic dilatation of the endocervical glands [17] ([Figure 3]). The typical MRI finding is multiple cystic lesions in the fibrous cervical stroma that have regular borders. The cysts have intermediate or slightly high signal intensity on T1-weighted images and have prominent high signal intensity on T2-weighted images. The cysts may have high signal intensity on DWI owing to the mucinous content (T2 shine-through). However, the lack of restriction on the ADC map enables differentiation of tunnel clusters from adenoma malignum.{Figure 2}{Figure 3}

Diagnostic clues: A multicystic lesion that invades the deep cervical stroma and contains solid components may suggest a malignancy. In contrast, benign lesions do not usually deeply invade the cervical stroma, are small, have well-defined margins, and do not contain solid components. On DWI, tunnel clusters do not have restricted diffusion, whereas adenoma malignum shows areas of restriction with decreased ADC.

Tunnel clusters may have high signal intensity on high-b-values owing to mucinous content. Evaluation of the ADC map may help in the diagnosis.

Application of MRI diffusion-weighted imaging on endometrial versus endocervical adenocarcinoma

Differentiating cervical from endometrial carcinoma is important because patient care differs for the two diseases. An accurate diagnosis of cervical versus endometrial carcinoma may not be possible with routine histopathologic analysis. MRI may help in this differentiation by depicting the bulk of the lesion in the cervix or endometrium. However, DWI itself cannot be used to differentiate the two tumors on the basis of ADC quantification.

The peritoneal cavity is a common location of metastatic spread of gynecologic malignancies, especially in patients with ovarian cancer.

Detection

The use of quantitative and qualitative DWI has been evaluated in the detection of peritoneal carcinomatosis. The remarkable difference in contrast between peritoneal lesions and surrounding organs on DWI enables detection of peritoneal dissemination. Mesenteric implants, bowel serosal implants, and metastatic lesions involving the peritoneal reflections around the liver, pancreas, and pelvis (surface of the uterus and bladder) are usually better seen on DWI [18]. Fujii and colleagues reported a sensitivity and specificity of 90 and 95.5%, respectively, for implant detection. It is important to recognize, however, that cardiac motion and susceptibility artifact from air can markedly degrade image quality at air-tissue interfaces and therefore obscure small peritoneal implants, especially on the bowel surface. Moreover, DWI provides little anatomic information. Therefore, it is necessary to interpret DWI in conjunction with conventional MRI.

The combined interpretation of DWI with conventional MRI increases the rate of detection of peritoneal deposits, particularly in the more challenging locations [19].

Mucinous implants may exhibit a T2 shine-through effect and high ADC value. The diffuse high signal intensity of the normal intestinal wall on high-b-value DWI may be misinterpreted as malignant infiltration.

 Conclusion



Functional imaging with DWI is becoming increasingly important in the evaluation of gynecologic cancer. DWI is of interest for tumor detection, characterization, and response to treatment. Its robust implementation necessitates optimized acquisition and experience in image interpretation. Correlation of DWI and conventional anatomic MRI sequences is critical to maximizing its value. Interpretation of DWI in isolation can lead to false-positive findings.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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