Maxilla–nasion–mandible (MNM) angle: an indicator to assess fetal facial profile in first-trimester of pregnancy

Qu, Su-hui; Wang, Mujun; Xu, Wenzhe; Zhang, Guangying; Zhang, Chengqi

doi:10.1186/s40064-016-2944-4

Cited by 3 publications

(4 citation statements)

References 18 publications

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“…In the present study, the mean MNM angle was 7.8 (± 2.1)°, which had some variations from the reports by the other two studies in Chinese populations (Ji et al and Liu et al reported 1.84–6.50° and 11.00°±2.58, respectively) [ 19 , 22 ]. We also found a positive correlation between MNM angle and CRL, which was consistent with the studies by Ji et al and Bakker et al, [ 9 , 19 ] but different from the result from Liu et al [ 22 ]. Our study found an increased MNM angle in fetuses with cleft lip and palate, micrognathia, and open spina bifida, similar to a previous study [ 9 ].…”

Section: Discussioncontrasting

confidence: 85%

Ultrasound measurements of fetal facial profile markers and their associations with congenital malformations during early pregnancy

Liao,

Wang,

Shang

et al. 2023

BMC Pregnancy Childbirth

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Background Fetal facial profile could be measured during the early pregnancy. Its abnormalities might be associated with certain congenital malformations. We aimed to study the associations between fetal facial profile measurements with crown-rump length and congenital malformations (cleft lip and palate, micrognathia, and open spina bifida) during early pregnancy. Methods We performed a prospective cross-sectional study between June 2019 and April 2022. Pregnant women at a gestational age between 11–13+ 6 weeks were enrolled. Two sonographers performed fetal facial profile measurements independently. The associations between these measurements with crown-rump length and congenital malformations were evaluated. Results There were 406 and 25 fetuses without or with congenital malformations, respectively. Two sonographers showed satisfactory inter- and intra-observer agreements and reproducibility. The maxillary gap was only observed in 7.6% of normal fetuses, whereas all cleft lip and palate fetuses had a maxillary gap ≥ 0.8 mm. The crown-rump length was negatively correlated with frontomaxillary facial angle, inferior facial angle, and profile line distance but positively correlated with maxilla-nasion-mandible angle, facial maxillary angle, frontal space distance, and palatine maxillary diameter. These measurements showed various significant changes with different congenital malformations. Conclusions Measurements of fetal facial profile in early pregnancy were feasible with satisfactory reproducibility. These measurements correlated with crown-rump length and showed significant differences with certain fetal congenital malformations.

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Section: Discussioncontrasting

confidence: 85%

Ultrasound measurements of fetal facial profile markers and their associations with congenital malformations during early pregnancy

Liao,

Wang,

Shang

et al. 2023

BMC Pregnancy Childbirth

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“…Considerable effort has been devoted to transforming such abnormal facial features into objective ultrasonographic facial markers. There are essentially three main categories of quantitative fetal facial marker: (1) length and ratio, including prenasal thickness, nasal bone length, prenasal‐thickness‐to‐nasal‐bone‐length ratio and prefrontal space ratio 3 , 4 ; (2) angles, including frontomaxillary facial angle, maxilla‐nasion‐mandible angle, frontonasal facial angle and mandibulomaxillary facial angle 5 , 6 , 7 , 8 ; and (3) facial profile line 4 . Some of these markers, such as prenasal‐thickness‐to‐nasal‐bone‐length ratio, frontomaxillary facial angle, prefrontal space ratio and facial profile line have been assessed individually for the prediction of trisomy 21 in the first trimester 3 , 4 , 5 , whilst the others have only been utilized in the second and third trimesters.…”

Section: Introductionmentioning

confidence: 99%

Application of an individualized nomogram in first‐trimester screening for trisomy 21

Sun

Zhang

Dong

et al. 2021

Ultrasound in Obstet & Gyne

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Objectives To develop and validate a nomogram based on fetal nuchal translucency thickness (NT) and ultrasonographic facial markers for screening for trisomy 21 in the first trimester of pregnancy. Methods This was a retrospective case–control study using stored two‐dimensional midsagittal fetal profile images captured at 11 + 0 to 13 + 6 weeks' gestation in singleton pregnancies. We included images from 302 trisomy‐21 pregnancies and 322 euploid pregnancies. Cases were divided into a training set (200 euploid + 200 with trisomy 21) and a validation set (122 euploid + 102 with trisomy 21) at a ratio of approximately 2:1. For each, the maternal age, gestational age, fetal NT and karyotype were noted, and 12 ultrasonographic fetal facial markers were measured. The least absolute shrinkage and selection operator (LASSO) method and multivariable analysis were used to select automatically the discriminative markers. Logistic regression was used to develop a LASSO model, based on the selected markers, to screen for trisomy 21 in the first trimester of pregnancy. Furthermore, 60 of the 624 images were selected randomly as a retest set to evaluate the model's robustness. The predictive performance of screening for trisomy 21 of a model based on fetal NT and maternal age and of the LASSO model was assessed using the area under the receiver‐operating‐characteristics curve (AUC). A nomogram was developed as an individualized tool to predict patient‐specific probability for trisomy 21, which is a more visual presentation of the LASSO model. The performance of the nomogram was assessed using the C‐index and calibration curve. Results Into the LASSO model were incorporated eight markers, including fetal NT, prenasal‐thickness‐to‐nasal‐bone‐length ratio, facial profile line, frontomaxillary facial angle, frontonasal facial angle, mandibulomaxillary facial angle, maxilla‐nasion‐mandible angle and d2 (distance between the anterior edge of the prefrontal skin and the mandibulomaxillary line) (all P < 0.05). The AUCs of the LASSO model for screening for trisomy 21 were 0.983 (95% CI, 0.971–0.994) in the training set and 0.979 (95% CI, 0.966–0.993) in the validation set, and these were higher than the AUCs of all eight individual ultrasonographic markers included in the model. The AUC of the LASSO model in the retest set was 0.997 (95% CI, 0.990–1.000), indicating good robustness of the LASSO model. The AUC of the LASSO model was significantly higher than that of the model based on fetal NT and maternal age in both training and validation sets (P < 0.001 for both). The nomogram of the LASSO model showed good discrimination of trisomy 21, with C‐indices of 0.983 in the training set and 0.981 in the validation set. Conclusions We present an individualized nomogram which incorporates fetal NT and a series of ultrasonographic facial profile markers selected by the LASSO method and multivariable analysis. This nomogram can potentially be utilized as a convenient and effective tool in screening for trisomy 21 in the first trimest...

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“…MNM has been successfully used in early and late pregnancies to evaluate facial abnormalities. It was shown to be a good indicator of retrognathia (often associated with trisomy 18), but a poor marker of trisomy 21 3,21,22 . In our study, we identified the MMN angle as a possible marker of trisomy 13.…”

Section: Discussionmentioning

confidence: 55%

“…A similar angle to the MMN angle is the maxilla‐nasion‐mandible (MNM) angle, 3,21,22 as it uses the same landmarks. The MNM angle has its vertex at the cross of two lines originating from the nasion to the anterior borders of the mandible and maxilla, respectively.…”

Section: Discussionmentioning

confidence: 99%

Assessment of the maxilla‐mandible‐nasion angle in normal and aneuploid foetuses in the first trimester of pregnancy

Tekesin¹,

Graupner²

2020

J of Clinical Ultrasound

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PurposeThis retrospective study aims to determine whether the maxilla‐mandible‐nasion (MMN) angle can be reliably measured in the first trimester, to describe normal ranges, and to determine if significant changes occur in foetuses with aneuploidies.MethodsThe MMN angle was measured in stored 2D‐ultrasound images of 200 normal fetal profiles between 11+0 and 13+6 weeks of gestation. Each image was analyzed by two observers at two independent time points. Bland‐Altmann analysis was performed to evaluate the reliability of the measurements. Additionally, the MMN angle was measured on sonograms from 140 aneuploid foetuses.ResultsThe mean MMN angle in normal foetuses from 11 to 14 weeks of gestation was 15.4°. Reliability of the measurement was high when repeatedly measured by the same observer (ICC = 0.92 and 0.82) and between two observers (ICC = 0.77 and 0.63). Average MMN values in foetuses with trisomy 21, 13, and Turner syndrome were significantly higher than those measured in normal foetuses. The highest differences were observed in foetuses with trisomy 13. Among those, 62% had an MMN angle above the 95th percentile and 92% above the normal mean.ConclusionThe MMN angle can be reliably measured in early pregnancy and is abnormal in about 60% of foetuses with trisomy 13.

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Maxilla–nasion–mandible (MNM) angle: an indicator to assess fetal facial profile in first-trimester of pregnancy

Cited by 3 publications

References 18 publications

Ultrasound measurements of fetal facial profile markers and their associations with congenital malformations during early pregnancy

Ultrasound measurements of fetal facial profile markers and their associations with congenital malformations during early pregnancy

Application of an individualized nomogram in first‐trimester screening for trisomy 21

Assessment of the maxilla‐mandible‐nasion angle in normal and aneuploid foetuses in the first trimester of pregnancy

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