Clinical Imaging xxx (2014) xxx–xxx

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Plicae palmatae: an anatomical uterine cervix variation to be considered on magnetic resonance images☆ Fatma Uysal a,⁎, Sibel Cevizci b, Mustafa Reşorlu a, Meryem Gencer c, Ahmet Uysal c a b c

Çanakkale Onsekiz Mart University, Department of Radiology, Çanakkale, Turkey Çanakkale Onsekiz Mart University, Department of Public Health, Çanakkale, Turkey Çanakkale Onsekiz Mart University, Department of Obstetrics and Gynecology, Çanakkale, Turkey

a r t i c l e

i n f o

Article history: Received 27 June 2014 Received in revised form 7 August 2014 Accepted 19 August 2014 Available online xxxx Keywords: Plicae palmatae Anatomical cervical variation MRI Uterus Endocervical folds

a b s t r a c t Objective: The aim of this study was to research the frequency and distribution of plicae palmatae in women in different age groups. Methods: Data of 409 female patients’ magnetic resonance images were evaluated. Results: We found a frequency of plicae palmatae variations in the study population of 44.5%. It was statistically most frequent in the fourth decade. The presence of plicae palmatae variations in the period after menopause was significantly lower than that during the reproductive period. Conclusions: Identification of plicae palmatae may be misdiagnosed as uterine septum and more awareness of this situation is required to prevent unnecessary surgery.

© 2014 Elsevier Inc. All rights reserved.

1. Introduction Magnetic resonance imaging (MRI) reveals the uterine structures in detail because of high soft-tissue contrast resolution. The zonal anatomy of the uterine cervix on T2-weighted magnetic resonance (MR) images appears as shiny signal intensity visible in the central part of the cervical epithelium with mucin in the cervical canal. While the inner cervical stroma has low intensity representing fibrous stroma, loose connective tissue of the outer cervical stroma shows slightly increased signal intensity [1]. Plicae palmatae is a normal endocervical fold, thought to be a remnant of the Mullerian ductal fold. Within the cervical canal, it is formed by a slight ridge along the center line and many small folds in the lateral sections [2]. Axial T2-weighted MR images show the plicae palmatae as a low signal intensity in longitudinal ridges on the midline of the front and/or rear wall of the cervical canal. Takahata et al. described this anatomy for the first time in a case study as a low-intensity linear structure located on the midline of the endocervix on T2-weighted images, demonstrated macroscopically on a pathologic specimen after uterine resection [3]. The clinical importance of this sign is that it may be mistaken for an anomalous uterine septum. To our knowledge, there are limited data on plicae palmatae in the English-language literature.

The aim of this study was to research the variations in plicae palmatae on MRI between different age groups and whether the frequency changes before and after menopause. 2. Materials and methods 2.1. Study population We retrospectively reviewed lower abdominal MR images from our archives, taken for a variety of reasons, from 409 women. Seventy-five cases with a history of hysterectomy were excluded from the study and 33 cases were excluded because of inappropriate examination quality (movement or artifacts due to prosthetic hip) or cervical evaluation not possible because of cervical malignancy, with cancer extending to the endometrium of the cervical canal. Two additional cases were excluded from the study because the cervix was not observed: one case had uterine agenesis and one case had vaginal atresia. The final study population included 299 patients. Ethical approval was received from Canakkale Onsekiz Mart University ethical committee prior to the study. 2.2. Imaging technique

☆ Conflict of interest: We declare that we have no conflict of interest. ⁎ Corresponding author. Çanakkale Onsekiz Mart University, Department of Radiology, Çanakkale, Turkey. Tel.: +90-5052874231. E-mail address: [email protected] (F. Uysal).

MR examinations were performed on a 1.5-T magnet unit (Signa HDx, GE Healthcare Medical Systems) with a phased-array body coil. The parameters for T2-weighted images were as follows: repetition time, 4000 ms; echo time, 100 ms; slice thickness, 4 mm; inter-slice

http://dx.doi.org/10.1016/j.clinimag.2014.08.003 0899-7071/© 2014 Elsevier Inc. All rights reserved.

Please cite this article as: Uysal F, et al, Plicae palmatae: an anatomical uterine cervix variation to be considered on magnetic resonance images, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.08.003

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F. Uysal et al. / Clinical Imaging xxx (2014) xxx–xxx

number (0.05/15=0.003) with a type 1 error significance level or Pb .003. According to the Bonferroni correction, the significant difference between the age groups was due to the influence of the 30–39 years group (Pb.003) (Table 1). The patients were also divided into two separate groups depending on predicted menopause and the frequency of observed plicae palmatae was again investigated using the chi-square analysis. In the ≤45 years group (n= 125), the average age was 33.2±9.1 years (range, 12–45 years) while the average age in the N45 years group (n=174) was 60.7±9.8 (range, 46–87 years). Plicae palmatae were identified in 58.4% (n= 73) of women ≤ 45 years and in 34.5% (n= 60) of women N 45 years. Chi-square analysis of the two groups revealed a statistically significant difference between the groups (Pb.001) (Table 2).

Table 1 Distribution of plicae palmatae according to age group Variable

Total patients

Plicae palmatae frequency

Age groups

(n)

n (%)

Pa

Pb

b30 30–39 40–49 50–59 60–69 70 and up

41 42 67 61 50 38

24 (58.5) 30 (71.4) 27 (40.3) 19 (31.1) 20 (40.0) 13 (34.2)

b.001

b.003

a b

Chi-square test. Post hoc test with Bonferroni correction.

gap, 0.5 mm; matrix, 256–384; and field of view, 240–360 mm. The axial and coronal T2-weighted images were evaluated by consensus by two radiologists. A low-intensity midline lineament or ridge along the center of the cervical canal of the plicae palmatae variation was identified and the frequency according to age group was determined. The radiology specialist was experienced for 6 years about gynecological radiology as well as women’s imaging.

4. Discussion We found that, on axial and coronal T2-weighted MR images, the presence of plicae palmatae variations in the uterine cervix was most frequently found in the 30–40 years age group, significantly more frequently than in the other groups. The frequency of plicae palmatae variations was also significantly reduced in the postmenopausal period compared with the premenopausal period. To our knowledge, to date, there are only two studies in the literature researching the frequency of plicae palmatae. The first frequency study on plicae palmate was completed in 2007 by Jack et al. who discovered a frequency of pseudoseptum, as they defined plicae palmatae, of 20–30% in the female population in their study. However, this study did not evaluate the age frequency of plicae palmatae [4]. The first and only frequency study on plicae palmate and the related age distribution was completed in 2009 by Takahata et al. [5]. The researchers evaluated T2-weighted MR images taken for a variety of reasons on 460 healthy women between the ages of 21 and 60 years. They reported a variation frequency of 42% in all women in their study. Our study included women between 12 and 87 years and found a frequency of plicae palmatae of 44.5%, slightly higher than in the other two studies (Table 3). Takahata et al. [3] used axial plane scans while El Jack et al. [4] used axial and coronal plane scans. In our study, some cases were axial plane, linked to the angle of the cervix, and in cases of doubt, coronal plane images were evaluated to confirm the presence or absence of plicae palmatae (Fig. 1). Jack et al. studied American women [4], Takahata et al. studied Japanese women [5], and we studied Turkish women. The possibility of plicae palmatae frequency differences due to ethnic or geographic reasons should be kept in mind. Takahata et al. determined that the variation frequency in the sixth decade (24.8%) was significantly lower than that for previous decades

2.3. Statistical analyses Statistical analyses were performed using SPSS software version 19.0 (SPSS Inc., Chicago, IL, USA). The frequency and percentage values of variations according to the age groups were presented using crosstabulations and the chi-square test was used to compare these proportions in different age groups. A P value of less than .05 was considered statistically significant. Bonferroni correction was used for multiple comparisons as a post hoc test. 3. Results The average age of the 299 patients in the study group was 49.2± 16.6 years (range, 12–87 years). In the current study population, 5 Mullerian anomaly cases (3 arcuate uteri, 1 uterus subseptus, and 1 uterine agenesis excluded), 1 vaginal agenesis case excluded, and 1 nuck canal cyst case were observed. Plicae palmatae with distinct low signal intensity on T2-weighted images were identified in 44.5% (133/299) of the patients. The 299 women in the study were divided into six age groups: b30 years; 30–40 years; 40–50 years; 50–60 years; 60–70 years; and N70 years. The frequency of observed plicae palmatae according to age group was investigated using the chi-square analysis. We found a statistically significant difference between the age groups (Pb.001). For pairwise comparison between the age groups, statistical significance was accepted as the lower group divided by the comparison Table 2 Incidence of plicae palmatae in the predicted premenopausal and postmenopausal periods Variable

Mean age

Total patients

Plicae palmatae frequency

Age groups

Year

(n)

n (%)

Pa

≤45 N45 12–87

33.2±9.1 (min, 12; max, 45) 60.7±9.8 (min, 46; max, 87) 49.2±16.6 (min, 12; max, 87)

125 174 299

73 (58.4) 60 (34.5) 133 (44.5)

b.001

a

Chi-square test.

Table 3 Comparison with previous studies according to decades

Takahata et al. [5] Present study

Second (11–20)

Third (21–30)

Fourth (31–40)

Fifth (41–50)

Sixth (51–60)

Seventh (61–70)

Eighth (71–87)

Overall

9/12 (75%)

31/59 (52.5%) 15/29 (51.7%)

47/99 (47.5%) 30/40 (71.4%)

67/126 (53.2%) 27/67 (40.3%)

37/149 (24.8%) 19/61 (31.1%)

20/50 (40%)

13/38 (34.2%)

182/433 (42.0%) 133/299 (44.5%)

Please cite this article as: Uysal F, et al, Plicae palmatae: an anatomical uterine cervix variation to be considered on magnetic resonance images, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.08.003

F. Uysal et al. / Clinical Imaging xxx (2014) xxx–xxx

Fig. 1. A 22-year-old woman without any gynecological complaints. Axial T2-weighted image demonstrates large elevation of distinct low signal intensity in the midline of the endocervix (arrows).

and proposed that this was due to uterine atrophy in women in this age group, recommending that more detailed studies were needed [5]. In contrast to previous studies, the groups in our study were investigated in more detail and statistically evaluated. The source of the difference between the age groups was evaluated using the Bonferroni correction and the variation frequency in women in the fourth decade (71.4%) was significantly higher than that in the other decades (chisquare test, Pb .001; post hoc testing with Bonferroni correction, Pb.003). The significance in this age group coincides with intense fertility and a mature cervix is a consideration as a cause of the increased frequency of plicae palmatae. To investigate the effect of uterine atrophy on the frequency of plicae palmatae, as proposed by Takahata et al. [5], the cohort was divided into two groups: N 45 years (n=174) and ≤45 years (n=125) based on the average age of menopause in the Turkish population [6]. The frequency of plicae palmatae in the ≤ 45 years group (58.4%) was significantly higher than the frequency in the N45 years group (34.5%, Pb.001). This result confirms the theory of Takahata et al. [5] and carries it a step further. Menopause and subsequent uterine atrophy may reduce the observed frequency of this variation. A limitation of the study by Takahata et al. [5] was the use of cases from three separate centers and therefore different images evaluated in different sequences. Our study was based at a single center and standardized using the same MRI sequences for all patients. Plicae palmatae is a normal endocervical folds, but it may not be remnant of the Mullerian ductal fusion. MR findings of plicae palmatae on uterus didelphys had been reported. In our series, there were 5

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Mullerian anomaly cases (3 arcuate uteri, 1 uterus subseptus, and 1 uterine agenesis excluded from study) [7]. The frequency of plicae palmatae in our patient population, especially the significant frequency in reproductive-age women, implies a point that requires caution. Mullerian anomalies are important when evaluating infertile patients in the reproductive period and the diagnosis and treatment of these anomalies involves invasive procedures such as hysteroscopy. For a radiologist, distinguishing plicae palmatae from a uterine septum is very important, and if the interpreter does not know these structures, confusion may occur [5]. When carefully examining axial images of the cervix, following the septum to the proximal section of the uterus could prevent confusion. If the structure is plicae palmatae, it will end in the lower segment of the cervical mucosa and will not be visible in the proximal section [8]. Distinguishing between plicae palmatae and uterine septum is important to avoid unnecessary hysteroscopy. A limitation of this study is that premenopausal and postmenopausal women were not proven by hormonal matching. Topics that require further investigation in prospective studies include whether the frequency of plicae palmatae is affected by the number of births and, most importantly, at what frequency they are observed in infertile patients. In conclusion, plicae palmatae are frequently seen on axial T2weighted images of the uterine cervical canal, especially in reproductive-age women, and the frequency decreases in the postmenopausal period. The identification of this variation in MR images is important to prevent confusion with uterine septum anomaly and to prevent unnecessary surgical intervention. Ethical standards The authors confirm that this studied complied with the current laws of the country in which it was performed. References [1] Scoutt LM, McCauley TR, Flynn SD, Luthringer DJ, McCarthy SM. Zonal anatomy of the cervix: correlation of MR imaging and histologic examination of hysterectomy specimens. Radiology 1993;186:159–62. [2] Kistner RW. Gynecology: Principles and Practice. 3rd edit. Chicago: Year Book Medical Publishers; 1980. [3] Takahata A, Koyama T, Yamada K, Nishimura T, Fujii S, Togashi K. Plicae palmatae of the cervical canal visualized on MRI. Br J Radiol 2008;81:e4–6. [4] El Jack AK, Siegelman ES. “Pseudoseptum” of the uterine cervix on MRI. J Magn Reson Imaging 2007;26:963–5. http://dx.doi.org/10.1002/jmri.21116. [5] Takahata A, Koyama T, Kido A, Kataoka M, Umeoka S, Nishizawa S, et al. The frequency of the plicae palmatae in the uterine cervix on MR imaging. Abdom Imaging 2009;34: 277–9. http://dx.doi.org/10.1007/s00261-008-9384-8. [6] Yangin HB, Kukulu K, Sözer GA. The perception of menopause among Turkish women. J Women Aging 2010;22:290–305. http://dx.doi.org/10.1080/08952841.2010. 518880. [7] Takahata A, Koyama T. Plicae palmatae of the cervical canals in uterus didelphys: MR imaging. Abdom Imaging 2012;37:912–3. [8] Scarsbrook AF, Moore NR. MRI appearances of mullerian duct abnormalities. Clin Radiol 2003;58:747–54.

Please cite this article as: Uysal F, et al, Plicae palmatae: an anatomical uterine cervix variation to be considered on magnetic resonance images, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.08.003

Plicae palmatae: an anatomical uterine cervix variation to be considered on magnetic resonance images.

The aim of this study was to research the frequency and distribution of plicae palmatae in women in different age groups...
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