Placenta accreta is the abnormal adherence of placenta to myometrium due to defect in decidua basalis. This type of placenta could not remove manually after delivery and lead to severe hemorrhage that may result in emergency cesarean hysterectomy. Prenatal diagnosis of placenta accreta is important because it reduces the fetal and maternal morbidity and mortality as appropriate pre-operative and per operative procedures are possible. Grey scale ultrasonography along with color Doppler imaging proves to be the non invasive, real time, readily available modality with high sensitivity and high positive predictive value

Afza, Shaista

Masroor, Imrana

Shafqat, Gulnaz

eCommons@AKU

with the cesarean section rate, has increased tenfoldin the past fifty years, with frequency of approximatelyone per thousand deliveries.4,5Placenta accreta is the abnormal adherence of placenta to myometrium due to defect in decidua basalis. This typeof placenta could not remove manually after delivery and lead to severe hemorrhage that may result in emergencycesarean hysterectomy. Prenatal diagnosis of placenta accreta is important because it reduces the fetal and maternalmorbidity and mortality as appropriate pre-operative and per operative procedures are possible. Grey scaleultrasonography along with color Doppler imaging proves to be the non invasive, real time, readily available modalitywith high sensitivity and high positive predictive value.Ke yw ords : Placenta accrete, Cesarean hysterectomy, Placenta previaABSTRACTCASE REPORTULTRASONOGRAPHIC DIAGNOSIS OF PLACENTA ACCRETAPJR October - December 2010; 20(4): 165-167165PJR October - December 2010; 20(4)PAK ISTAN JOURNAL  OF RADIOLOGYShaista Afzal, Imrana Masroor, Gulnaz ShafqatCorre s ponde nce  : Dr. Shaista AfzalDepartment of Radiology,Aga Khan University Hospital,Stadium Road, P.O. Box 3500, Karachi 74800Pakistan. Tel. No: 34930051 - Ext. 2020Email: shaista.afzal@aku.eduIntroductionPlacenta accreta is a placental disorder in which thereis direct contact between the placenta and themyometrium. Three variants of condition are recognizedbased on pathologic invasion of myometrium bychorionic villi. In most common form (70-80%) placentais directly attached to the myometrium and is termedas placenta accreta. In approximately 17% of casesplacenta extends deep into myometrium and is knownas placenta increta. In remaining 5-7% of casesplacenta extends through the entire wall of the uterusand termed percreta.Risk factors for placental invasion are prior uterineinstrumentation or surgery that would have disruptedthe endometrial layer1,2 and increasing maternal age.4Uterine scarring from previous cesarean sectionincreases the prevalence of placenta previa from0.26% with an unscarred uterus to 0.65% after onecesarean section and to as much as 10% after fourcesarean sections.2The frequency of placenta accreta in the presence ofplacenta previa increases from 24% after one cesareansection to 67% after four or more cesarean sections.3The incidence of placenta accreta, which is correlatedDepartment of Radiology, Aga Khan University Hospital, Karachi, Pakistan.Cas e  Re portThis is a case report of 31 years old non booked 36weeks pregnant patient came through emergency withepisode of heavy of vaginal bleeding. She had twoprevious cesarean sections because of feto pelvicdisproportion. Her previous two ultrasounds was doneoutside our center showed, type four placenta previa.Ultrasound at our center performed with 3.5 MHz lineararray transducer (Aloka Prosound 4000) at 36 weeksof gestation showed, single viable fetus of 35+ weeksof gestation with adequate liquor. Placenta was lowlying completely covering internal os. On detailed scanof placenta non visualization of the retroplacentalecholucent clear zone was noted with reducemyometrial thickness less than 1mm between theplacenta and the bladder wall. Color Doppler imagingconfirmed the diagnosis by showing the parallel runningvessels at the outer margin of urinary bladder wall withlow resistance placental flow. Placenta was labeledas type four previa with placenta increta.Emergency cesarean section was performed becauseof profuse vaginal bleeding. On surgery it was found166PJR October - December 2010; 20(4)PAK ISTAN JOURNAL  OF RADIOLOGYthat placenta was inseparable from the myometriumand lie beneath the bladder wall. Cesarean sectionended up on cesarean hysterectomy because ofhemorrhage. Postoperatively mother was transfused4 pints of packed cell in special care where she stayedfor two days. Rest of the postoperative period wasuneventful and was discharged on 7th postoperativeday from the hospital with healthy baby.Histopathology report showed, chorionic villi traversingthe myometrium without intervening deciduas basilisconfirming the diagnosis of placenta increta.diagnosis since placenta accreta encounteredunexpectedly can lead to excessive blood loss,Sheehan syndrome, renal failure and other multiplecomplications. Cesarean hysterectomy is the end resultbecause of excessive haemorrhage.7,8Thus placenta accreta and especially placenta percretahave been reported to result in mortality rate of 7%.7Prenatal diagnosis is essential for appropriatecounseling and surgical planning to be performed.Literature search revealed that diagnosis of placentaaccrete is possible by ascertaining certain ultrasono-grphic feature on grey scale as well as on colourDoppler imaging. Sonographic features suggestingplacenta accrete are placental lacunae which has thehighest sensitivity of 93%.8,10Lacunae appear as rounded or tubular structures withinthe placenta usually but not always show turbulentflow within them.Other associated  features includes thinning ofhypoechoic retroplacental myometrium less than 1mm,thinning or disruption of the hyperechoic uterine serosawith bladder interface and loss of clear space that isdeciduas basalis between the myometrium and theplacenta.10,11On colour Doppler imaging placental and arcuatevessels are visualized in the suspicious area ofmyometrium. Easily recognizable low pulsatile andlow resistance flow in the intervillous space can reflecta connection between the myometrial arteries andplacental tissues.8,9In our case on grey scale imaging type four placentaprevia with thining of hypoechoic retroplacentalmyometrium less than 1mm and loss of clear spacebetween the myometrium and the placenta was noted.Colour Doppler was applied which showed lowresistance placental flow in suspicious area on Dopplerimaging.The sensitivity and specificity of ultrasound in thediagnosis of Placenta Accreta is 86% and 71%respectively.8Magnetic Resonance Imaging can also noninvasivelydetect placenta accreta. MRI features for placentaaccreta are focal thinning of the myometrium andinterruption of the junctional zone. On T2-weightedMR images, the mass is hyperintense or may beheterogeneous.9,10 But definitely this modality cannotbe used for screening purpose and reserved for thosepatients in whom placentas which are difficult toevaluate with ultrasound.Figure  A: Type 4 previa with loss of myometrial zone between theplacenta and the posterior wall of the bladder.Figure  A: On doppler imaging low resistance placental flow isidentified beneath the bladder wallDis cus s ionPlacenta accrete is a placental abnormality that mayresult in substantial intrapartum morbidity andmortality.6 There is a need for reliable antenatal167PJR October - December 2010; 20(4)PAK ISTAN JOURNAL  OF RADIOLOGYConclus ionCorrect management of patients with placenta previawith additional placenta accrete increta or percreta ispossible only with accurate antenatal diagnosis whichis also a prerequisite for reduction of possible morbidityof both mother and child.9.10.11.De Mendonca LK. Sonographic diagnosis ofPlacenta Accreta Presentation of Six Cases JUltrasound Med 1988; 7: 211-5.Twickler DM, Lucas MJ, Balis AB, Santos-RamosR, Master L, Malone S, Roger B. Color flow mappingfor myometrial invasion in women with a priorcesarean delivery J Matern Fetal Med 2000; 9 :330-5.Wong H S,Cheung Y K, Zuccollo J,Tait J,PringleKC. Evaluation of Sonographic Diagonostic Criteriafor Placenta Accreta. J Clin Ultrasound 2008;36:551-9.Re fe re nce s1.2.3.4.5.6.7.8.Middleton DW, Kurtz B A, Hertzberg B S. Placenta,Umbilical cord, and Cervix. In; Alfred B Kurtz,William D Middelton, Barbra S Hertzberg edt.Ultrasound The Requisite Mosby 2004 486-510.Levine D, Hulka CA, Ludmir J, LIW, Edelmen RO.Placenta accreta: evaluation with color DopplerUS, power Doppler US, and MR imaging. Radiology1997; 205: 773-6.Clark SL, Koonings PP, Phelan JP. PlacentaPrevia/accrete and prior cesarean section Obstet.Gynaecol 1985; 66: 89-92.Miller DA, Chollet JA, Gordwin TM. Clinical riskfactor for placenta previa – Placenta Accreta. AmJ Obstet Gynaecol 1997; 177: 210-4.Placenta Accreta ACOG Committee Opinion No266 American College of Obstetricians andGynaecologists. Int J Gynaecol Obstet 2002; 77:77-8.Kayern G, Davy C, Goffiner F, Thomas C, ClermetD, Carbrol D. Conservative versus extirpativemanagement in cases of Placenta accreta. ObstetGynecol 2004; 104: 531-6.Antenatal diagnosis of Placenta Accreta: a reviewUltrasound Obstet Gynaecol 2005; 26: 89-96.Comstock CH, Love JJ, Bronsten RA, VettarainoI , Huang R,  Lorenz R. Sonographic detection ofPlacenta Accreta in the second and third trimesterof pregnancy Am J Obstet Gynaecol 2004; 19 0:1135-40.

ULTRASONOGRAPHIC DIAGNOSIS OF PLACENTA ACCRETA

http://www.pakjr.com/ojs/index.php/PJR/article/download/398/423

ULTRASONOGRAPHIC DIAGNOSIS OF PLACENTA ACCRETA

Abstract

Similar works

Full text

Available Versions

eCommons@AKU