Al-Azhar Assiut Medical Journal

ORIGINAL ARTICLE
Year
: 2019  |  Volume : 17  |  Issue : 1  |  Page : 103--107

Evaluating the role of MRI with diffusion-weighted images in diagnosis of uterine focal lesions


Hoda A.E Abd Elsamie1, Mahmoud I El-Rasheedy2, Mohammed A.A Mohammed2,  
1 Department of Radiodiagnosis, Al Azhar University, Assiut, Egypt
2 Department of Obstetrics and Gynecology, Faculty of Medicine, Al Azhar University, Assiut, Egypt

Correspondence Address:
Mahmoud I El-Rasheedy
Obstetrics and Gynecology Department, Faculty of Medicine, Al Azhar University, Assiut, 85811
Egypt

Abstract

Objective The aim of this study is to highlight the role of MRI with diffusion-weighted (DW) images in diagnosis of uterine focal lesions, especially in differentiation between benign and malignant masses, and initial staging of known malignancies. Patients and methods A total of 34 patients with uterine focal lesion were included in the study. The patients’ age ranged from 25 to 87 years old, with mean age of 49.6 years. All the patients were referred from the Obstetrics and Gynecology Department to Radiodiagnosis Department at Al Azhar Assiut University Hospital during the period from November 2017 to October 2018. Results In this study, DW MRI could correctly diagnose 33 of 34 lesions. It correctly diagnosed 22 of 22 benign lesions (facilitate diffusion) and 11 of 12 malignant lesions. Overall, 11 malignant lesion showed restricted diffusion, and only one malignant lesion showed facilitated diffusion. Conclusion This study suggests that, in addition to conventional MRI features, DW imaging provided an additional tool for distinguishing uterine benign focal lesions from malignant lesions.



How to cite this article:
Abd Elsamie HA, El-Rasheedy MI, Mohammed MA. Evaluating the role of MRI with diffusion-weighted images in diagnosis of uterine focal lesions.Al-Azhar Assiut Med J 2019;17:103-107


How to cite this URL:
Abd Elsamie HA, El-Rasheedy MI, Mohammed MA. Evaluating the role of MRI with diffusion-weighted images in diagnosis of uterine focal lesions. Al-Azhar Assiut Med J [serial online] 2019 [cited 2020 Jul 5 ];17:103-107
Available from: http://www.azmj.eg.net/text.asp?2019/17/1/103/266739


Full Text



 Introduction



Uterine masses as part of female pelvic masses have a broad differential diagnosis, including benign and malignant neoplasms and non-neoplastic diseases. Many pelvic masses are a diagnostic challenge, given the proximity to a variety of pelvic structures and the overlap of specific imaging features among different diagnoses [1],[2].

Ultrasound (US) is often the first-line imaging modality for the evaluation of uterine masses in female pelvis; however, US may be limited by poor acoustic windows and poor depth of penetration, preventing characterization of some masses. Computed tomography is limited in the pelvis by a lack of soft-tissue contrast, which becomes problematic when, for example, trying to differentiate decompressed bowel from adnexal structures. MRI, on the contrary, provides excellent contrast resolution, resulting in accurate tissue characterization and improved anatomic delineation [1],[2].

Recent technical advances in diffusion-weighted imaging (DWI) greatly enhanced the clinical value of MRI of the body. DWI can provide excellent tissue contrast based on molecular diffusion and may be able to demonstrate malignant tumors. Quantitative measurement of the apparent diffusion coefficient (ADC) may be valuable in distinguishing between malignant and benign lesions [3].

Diffusion-weighted (DW)-MRI is a functional imaging technique whose contrast derives from the random motion of water molecules within tissues. Its use has been established as a useful functional imaging tool in neurologic applications for a number of years, but recent technical advances now allow its use in abdominal and pelvic applications [4].

The diffusion of water molecules is affected by the extent of tissue cellularity and the presence of intact cell membranes. As a result, tissues with low cellularity and defective cell membranes have relative increase in extracellular space allowing free water diffusion. On the contrary, in highly cellular tissues (as in viable tumors), water diffusion is restricted because of reduced extracellular space and by intact cell membranes, which act as barrier to water movement [3].

 Patients and methods



This prospective study was carried out in Department of Radiodiagnosis Al Azhar University Hospital, Assiut, during the period from November 2017 to October 2018. Ethics committee approvals in addition to informed written consent were obtained from all patients. A total of 34 patients with uterine focal lesions were included in the study. The patient’s age ranged from 25 to 87 years old, with mean age of 49.6 years. Inclusion criteria were patients who clinically or radiologically (US and computed tomography) had uterine focal lesion or patients suspected clinically to have uterine focal lesion such as patients with abnormal vaginal bleeding with abnormal thickened endometrium seen by US examination. Exclusion criteria included all patients with absolute contraindication to MRI (patients having cardiac pacemakers prosthetic heart valves, cochlear implants or any metallic implants), patients having history of claustrophobia, and patients who did not consent to be a part of the study.

All the patients were subjected to the following:Full history taking: age, parity, time of menopause, past history of gynecological troubles or operations, and positive family history of gynecological malignancy.Gynecological examination.US examination: all patients had undergone preliminary pelvic US by transabdominal and transvaginal ultrasound approaches using 3–4 and 7–8 MHz probes, respectively. Color Doppler was superimposed on masses to detect vascularity. The examination was performed on high-resolution US machine (Siemens Acuson ×300, Munich, Germany).MRI examination: MRI was performed on a 1.5-Tesla MRI unit (Philips Achieva). All the patients were imaged in the supine position using pelvic phased-array coil. Patients fasted for 3 h. Intravenous administration of an antispasmodic drug (10 mg of Visceralgine; Organon, Livron, France) was given immediately before MRI to reduce bowel peristalsis.

Examination protocol

Localizer images in axial, coronal, and sagittal planes were taken.Fast spin echo T1-weighted images (TR 497 ms, TE 12 ms, matrix 320×512, slice-thickness: 4–5 mm with an interslice gap of 1–2 mm, FOV 250 mm and a flip angle of 90) in axial and sagittal planes were taken.Fast spin echo T2-weighted images (TR 3.3 s, TE 90 ms, matrix 256×512, slice-thickness: 4–5 mm with an interslice gap of 1–2 mm, FOV 250 mm a flip angle of 90) in axial, coronal, and sagittal planes were taken.DW MRIs using a single-shot spin echo planar sequence with free breathing were acquired on axial plane using; the following parameters were used: TR 2.8 s, TE 72, matrix 512×512, and slice-thickness 4 mm, with an interslice gap of 1 mm and FOV 300 mm. The diffusion-sensitizing gradients were applied using a b factor of 0, 50, 500, and 1000 s/mm2 in each patient. ADC maps were automatically generated for all DWIs, and ADC values were measured at b value of 1000 s/mm2.

MRI analysis

MRI were analyzed for the following: size of the tumor (the greatest diameter), site (myometrium, endometrium, or cervix), signal intensity of the tumor on T1-weighted and T2-weighted and DWIs, the tumor margin, parametrial invasion, presence of ascites, presence of infiltrated pelvic or para-aortic lymph nodes, involvement of other pelvic organs, and presence of peritoneal and omentum deposit.

Pathological correlation

The DW MRI finding was correlated with histopathological assessment as a gold standard.

Statistical analysis

All statistical calculations were done using statistical package for the social sciences (SPSS, version 19). Data were statistically described in terms of range, mean, SD, frequencies (number of cases), and percentages when appropriate. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for conventional MRI and DWI were calculated separately for each parameter.

 Results



The 34 patients included in this study were classified according to their histopathological results of the lesions: benign group (22 lesions; 64.7%) and malignant group (12 lesions; 35.3%). The most common benign lesion was uterine leiomyoma (15/22) whereas the most common malignant lesion was endometrial carcinoma (7/12), followed by cervical carcinoma (5/12) ([Table 1]).{Table 1}

In this study, all benign uterine focal lesions (22 lesions) are diffusion negative (facilitated diffusion) ([Table 2]).{Table 2}

[Table 3] shows the findings of DWI and ADC map in all benign uterine lesions.{Table 3}

[Table 4] shows conventional MRI findings in the malignant uterine focal lesions (n=12).{Table 4}

In this study, 12 malignant uterine lesions were included; 11 of the malignant uterine lesions were diffusion positive (restricted diffusion), presenting with high signal intensity at DWI with high b value (b=1000) and with low signal intensity at ADC images, whereas only one malignant uterine focal lesion (endometrial carcinoma) was diffusion negative (facilitated diffusion), presenting with intermediate signal intensity at DWI with high b value (b=1000) and with high signal intensity at ADC images.

[Table 5] shows the findings of DWI and ADC map in the studied malignant uterine lesions (n=12).{Table 5}

In this study, conventional MRI could correctly diagnose 31 of 34 lesions. It correctly diagnosed 21 of 22 benign lesions and 10 of 12 malignant lesions, achieving 83.3% sensitivity, 95.4% specificity, 90.9% positive predictive value (PPV), 91.3% negative predictive value (NPV), and 91.17% accuracy.

In this study, DW MRI could correctly diagnose 33 of 34 lesions. It correctly diagnosed 22 of 22 benign lesions (facilitate diffusion) and 11 of 12 malignant lesions. Of the 12 malignant lesions, 11 showed restricted diffusion, and only one malignant lesion showed facilitated diffusion, achieving 91.6% sensitivity, 100% specificity, 100% PPV, 95.6% NPV and 97.05% accuracy.

 Discussion



This study included 34 patients with uterine focal lesions. Their ages ranged from 25 to 87 years, with mean age of 49.6 years. The studied 34 lesions were divided into benign and malignant lesions, with uterine leiomyomas being the most common benign uterine lesion (15/22 lesions) followed by endometrial polyp (3/22 lesions), and endometrial carcinoma was the commonest malignant lesion (7/12 lesions) followed by cervical carcinoma (5/12 lesions). This agrees with Kilickesmez et al. [5] who stated that according to their study leiomyoma is the most common benign lesion of the uterus, whereas endometrial carcinoma is the most common malignant lesion followed by cervical cancer.

In this study, all ordinary leiomyomas showed low signal intensity (SI) on DW and ADC images likely owing to the ‘T2 blackout effect’, whereas degenerated leiomyomas showed low SI on DWIs and high SI on ADC images, which means that all leiomyomas showed diffusion negative (facilitated diffusion).

This was in agreement with the results of Thomassin-Naggara et al. [6], who found that all leiomyomas, either ordinary (15 lesion) or degenerated (seven lesions), had DWI low signal intensity, and Namimoto et al. [7], who concluded that all studied ordinary leiomyomas (95) were diffusion negative with low SI on DWI.

In this study, all benign endometrial lesions (three polyps and two hyperplasia) were diffusion negative; four lesions showed low SI on DWIs at high b value (b=1000) and with high SI on ADC images, whereas one endometrial hyperplasia showed high SI on both DWIs and ADC images. Of the studied seven malignant endometrial cancers, six were diffusion positive, presenting with high SI on DWIs at high b values (b=1000) and with low SI on ADC images, whereas one endometrial cancer was diffusion negative, presenting with intermediate high SI on DWIs at high b value (b=1000) and with high SI on ADC images.

Our results were nearly in agreement with the results of a study performed by Wang et al. [8], who used b value of 1000 s/mm2 and found that endometrial carcinoma like normal endometrium displayed hyperintense signal on DWI, whereas all endometrial polyps displayed intermediate signal or a relatively lower signal compared with the spared myometrium.

This study showed 85.7% sensitivity and 100% specificity of DWI and ADC images in diagnosis of endometrial lesions. This agreed with Bharwani et al. [9] who stated that the addition of DWI to conventional MRI has increased the sensitivity and specificity to 86 and 100%, respectively, in the diagnosis of uterine endometrial lesions, and Kamiyama et al. [10] reported that the sensitivity and specificity of DWI in endometrial lesions were 100 and 81%, respectively. We had one false-negative lesion, which was diagnosed radiologically as benign endometrial hyperplasia, whereas histopathology results proved it to be a well-differentiated adenocarcinoma owing to its low cellularity. This was in coincidence with Whittaker et al. [4] who reported that some malignant tumors have low cellularity (e.g. well-differentiated adenocarcinoma) and hence more limited water restriction that can be not seen on DWI.In this study, all cervical malignancies are diffusion positive, presenting with high SI on DWIs at high b values (b=1000) and of low SI on ADC images, with sensitivity and specificity of 100%. This nearly matched with other studies such as Hoogendam et al. [11] who reported that in cervical tumors, the DWI and ADC images gave sensitivity and specificity of 90 and 94%, respectively, and Chen et al. [12] revealed high sensitivity and specificity of 96 and 100%, respectively.

 Conclusion



This study suggests that, in addition to conventional MRI features, DWI provided additional tool for distinguishing uterine benign focal lesions from malignant lesions. DW-MRI enables qualitative and quantitative assessment of tissue diffusivity. DWIs in conjunction with ADC images are effective in the differentiation between benign and malignant uterine focal lesions. Malignant lesions show restricted diffusion pattern with high SI on high b values images with low SI on ADC images. Benign lesions shows facilitate diffusion with low SI on DWI. In our study, the accuracy of DWI and ADC images in differentiation between benign and malignant uterine lesions reaches ∼97.05%, with 91.6% sensitivity, 100% specificity, 100% PPV, and 95.6% NPV.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Bazot M, Darai E, Nassar-Slaba J, Lafont C, Thomassin N. Value of magnetic resonance imaging for the diagnosis of female pelvis tumors: a review. J Comput Assist Tomogr 2008; 32:712–723.
2Sohaib SA, Mills TD, Sahdev A, Webb JA, Vantrappen PO, Jacobs IJ, Reznek RH. The role of magnetic resonance imaging and ultrasound in patients with adnexal masses. Clin Radiol 2005; 60:340–348.
3Pagani E, Bizzi A, Di Salle F, De Stefano N, Filippi M. Basic concepts of advanced MRI techniques. Neurol Sci 2008; 29:290–295.
4Whittaker C, Coady A, Culver L, Rustin G, Padwick M, Padhani AR. Diffusion weighted MR imaging of female pelvic tumors: a pictorial review. Radio Graphics 2009; 29:759–778.
5Kilickesmez O, Bayramoglu S, Inci E, Cimilli T, Kayhan A. Quantitative diffusion-weighted magnetic resonance imaging of normal and diseased uterine zones. Acta Radiol 2009; 50:340–347.
6Thomassin-Naggara I, Dechoux S, Bonneau C, Morel A, Rouzier R, Carette MF et al. How to differentiate benign from malignant myometrial tumours using MR imaging. Eur Radiol 2013; 23:2306–2314.
7Namimoto T, Yamashita Y, Awai K, Nakaura T, Yanaga Y, Hirai T et al. Combined use of T2-weighted and diffusion-weighted 3-T MR imaging for differentiating uterine sarcomas from benign leiomyomas. Eur Radiol 2009; 19:2756–2764.
8Wang J, Yu T, Bai R, Sun H, Zhao X, Li Y. The value of the apparent diffusion coefficient in differentiating stage IA endometrial carcinoma from normal endometrium and benign diseases of the endometrium: initial study at 3-T magnetic resonance scanner. J Comput Assist Tomogr 2010; 34:332–337.
9Bharwani N, Miquel ME, Sahdev A. Diffusion-weighted imaging in the assessment of tumour grade in endometrial cancer. Br J Radiol 2011; 84:997–1000.
10Kamiyama T, Fukukura Y, Takumi K, Mikami Y, Fujii S, Togashi K. Diffusion-weighted imaging of uterine endometrial cancer using the apparent diffusion coefficient value at 3.0 T MRI: differentiation endometrial cancer from normal endometrium and endometrial benign lesions. Proc Intl Soc Mag Reson Med 2010; 18:4761.
11Hoogendam J, Klerkx M, de Kort G. Differentiation between malignant and benign cervical tissue on the basis of the apparent diffusion coefficient is sensitive and independent of the b-value combination used for ADC calculation. Proc Intl Soc Mag Reson Med 2010; 17:87.
12Chen B, Hu M, Chen L, Hu D, Liao J. Staging of uterine cervical carcinoma: whole-body diffusion-weighted magnetic resonance imaging. Abdom Imaging 2011; 36:619–626.