Ultrasound Obstet Gynecol 2016; 47: 276–278Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/uog.15810

Editorial

Pro forma for ultrasound reporting insuspected abnormally invasive placenta(AIP): an international consensus

Z. ALFIREVIC*, A.-W. TANG*,S. L. COLLINS†, S. C. ROBSON‡ andJ. PALACIOS-JARAQUEMADA§, on behalf ofthe Ad-hoc International AIP Expert Group*Department of Women’s and Children’s Health, University ofLiverpool, Liverpool, UK; †John Radcliffe Hospital, Oxford, UK;‡University of Newcastle, Newcastle, UK; §University of BuenosAires, Buenos Aires, Argentina*Correspondence. (e-mail: zarko@liv.ac.uk)

Accurate antenatal diagnosis of an abnormally invasiveplacenta (AIP), allowing multidisciplinary management atthe time of delivery, has been shown to improve maternaland fetal outcomes1–3. AIP can be predicted as early asin the first trimester, by identifying cases of suspectedCesarean scar pregnancy (CSP), as there is evidence thatCSP in the first trimester and AIP in the second andthird trimesters may represent different stages of a similarpathology4. Grayscale ultrasonography, with or withoutcolor Doppler and performed both transabdominallyand transvaginally, has been used widely for antenatalscreening and diagnosis of AIP. Many signs have beensuggested, with reports varying as to their sensitivity andspecificity5. Most of these ‘signs’ are poorly defined and,consequently, it is difficult to assess which are the mostrobust. To address this, the European Working Groupon AIP (EW-AIP) have produced a consensus proposalto standardize the ultrasound descriptions used to defineeach sign, published in this issue of the Journal6.

We assembled an international group of expertsin the field with the specific aim of reaching anagreement regarding a standardized means of reportingultrasound assessment of suspected AIP. If adopted bysonographers, clinicians and researchers worldwide, sucha pro forma may facilitate better communication, andbetter evaluation of our diagnostic performance, in casesof suspected AIP.

The group of international experts comprised ane-mail discussion group (n = 50) led by Jose PalaciosJaraquemada, members of the EW-AIP (n = 19) andmembers of the ISUOG (International Society ofUltrasound in Obstetrics and Gynecology) ClinicalStandards Committee (n = 7). Each expert was asked toparticipate in a survey which involved completion of anonline questionnaire to indicate what they believed shouldbe included in the pro forma for reporting ultrasoundassessment of suspected AIP.

The online questionnaire, created using Survey Mon-key, included risk factors known to be associated withAIP and all commonly reported ultrasound signs anddefinitions related to the diagnosis of AIP5–11. Ultra-sound signs were divided into three subgroups accordingto modality: grayscale ultrasound, color Doppler andthree-dimensional (3D) power Doppler. Each ultrasoundsign in each subgroup had between one and six associateddefinitions reported in the published literature.

To each selected demographic characteristic andultrasound sign we assigned three options: (i) definitelyinclude in report; (ii) include optionally in report and(iii) do not include in report. The definitions for eachultrasound sign were also assigned three options: (i)include; (ii) do not include and (iii) unsure. Participantswere also asked whether clinical interpretation andrelevance of the ultrasound findings should be includedin the report. Options for preferred method of reportingclinical interpretation included: (i) give probability ofclinically significant AIP, (ii) state whether manualremoval of placenta should be attempted, and (iii) givefree text description to provide guidance to the local team.There was the opportunity to provide free text commentsfor each section. A reminder to complete the questionnairewas sent out after 2 weeks, and we allowed 4 weeks for aresponse.

All demographic characteristics and ultrasound signsfor which >50% respondents selected ‘definitely includein report’ were incorporated into the standardized report,while those for which >50% respondents selected ‘donot include in report’ were excluded. For each ultrasoundsign, the definitions for which >50% of respondentsselected either ‘include’ or ‘unsure’ were kept for furtherevaluation. A second questionnaire was created for suchitems requiring further evaluation, in which respondentscould specify first and second choice for definition ofthe ultrasound sign, and included additional suggestionsfrom the free text comments, such as assessment forsuspected parametrial involvement. For confirmation,we distributed a third and final round of the survey,with three domains, addressing: demographic and riskfactors, ultrasound signs and clinical interpretation. Atthis round, consensus was sought from all participantsthat the ultrasound signs previously agreed on should bedefined using the standardized descriptors proposed bythe EW-AIP6.

There were 42 respondents in the first round of thesurvey (response rate, 55%). For all of the demographiccharacteristics, placental location and grayscale ultra-sound parameters, and for all but one color Dopplerparameter, >50% of respondents chose ‘definitelyinclude in report’. Only seven respondents thoughtthat 3D power Doppler volumes should definitely beincluded and thus this criterion was excluded. All

Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd. EDITORIAL

Ad hoc international AIP expert group 277

but one respondent agreed that clinical interpretationshould be included in the standardized report. Thepreferred option for reporting clinical relevance wasas probability of clinically significant AIP. There werealso suggestions to include reporting of assessment ofparametrial involvement and the extent of AIP (‘focal’ or‘diffuse’), which were included as options in subsequentrounds.

In the second round, 28 (37% of the original group)responded. All demographic characteristics suggestedadditionally in this round were selected by a clearmajority as to be definitely included in the report. Inthe third and final round (response rate, 42% of theoriginal group (n = 32)), agreement was obtained fromall respondents regarding the description of ultrasoundsigns, and the majority (87%) preferred categorizationof clinical relevance for significance of AIP into high,intermediate or low risk.

We propose that, when performing an ultrasound scanfor suspected AIP, this set of ultrasound signs shouldalways be reported. (See ultrasound report on next page,also supplied in pdf format online.) Using these standard-ized descriptors and this reporting pro forma should facil-itate a systematic approach to the assessment of this rarecondition. This should allow better comparison betweendiagnostic centers and enable prospective multicenterevaluation of the diagnostic performance of each sign, orcombination of signs, for prediction of AIP, thus reducingthe risk of serious perinatal complications and maternalmorbidity.

We propose that, at present, 3D color Doppler shouldnot be included in the standardized reporting of suspectedAIP. However, centers with experience in this ultrasoundmodality should continue to evaluate it and report itoptionally. This pro forma can also be further adaptedfor local use to include other findings, such as locationof cord insertion and placenta, to assist in planning theoperative technique for management of AIP.

The consensus to include clinical interpretation of ultra-sound findings was somewhat unexpected. The panel feltthat such interpretation is important in order to allow bet-ter planning of the intrapartum management within a mul-tidisciplinary team. The current proposal is to have threedifferent levels of suspected risk. It is anticipated that casesof low risk will receive standard care. How best to incor-porate the other two levels of risk into clinical pathways

will depend on local circumstances, maternal view onfuture fertility and surgical and critical-care expertise.

Members of the Ad-hoc International AIP ExpertGroup

The Ad-hoc International AIP Expert Group comprised:Zarko Alfirevic, Michael A. Belfort, Amar Bhide,Thorsten Braun, Pavel Calda, Giuseppe Cali, GihadChalouhi, Kinga Chalubinski, Frederic Chantraine,Min Min Chou, Sally Collins, Ekaterini Domali, AnaEspinosa, Tullio Ghi, Markus Gonser, Jorge Hamer,Irene Hoesli, Andrew D. Hull, Eric Jauniaux, Boon H.Lim, Phillip Lim, Shigeki Matsubara, Felipe Moretti,Donal O’Brien, Per Olofsson, Jose Palacios-Jaraquemada,Pedro Pinto, Steve Robson, Loı̈c Sentilhes, Jin-ChungShih, Alexandros Sotiriadis, Vedran Stefanovic, MinnaTikkanen, Ilan Timor-Tritsch, Boris Tutschek, Heleenvan Beekhuizen, Oliver Vasilj, Constantin von Kaisenbergand Katharina von Weizsaecker.

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A sample pro forma is shown on next page

An electronic version of the pro forma isprovided in the online version of this article.

Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd. Ultrasound Obstet Gynecol 2016; 47: 276–278.

278 Alfirevic et al.

Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd. Ultrasound Obstet Gynecol 2016; 47: 276–278.