الفهرس 
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Abstract
Obstetric haemorrhage is one of the leading causes of maternal death in developing countries, and abnormal placentation (accreta, increta, and percreta) has surpassed uterine atony as the most common reason for peripartum hysterectomy. However, these placental abnormalities are rarely detected before delivery.
PAS is associated with some of the most dreaded complications like exsanguinating hemorrhage, especially when efforts are made to manually separate an adherent placenta which was previously undiagnosed leading to hypovolemic shock, metabolic acidosis, complications of multiple blood transfusions, need for critical care, multiorgan dysfunction, acute renal failure and mortality. Most of these complications can be prevented if PAS is diagnosed in the antenatal period.
When compared to color Doppler, 3DPD allows observation of small vessels with relatively low velocity blood flow, and it also detects blood flow in vessels smaller than 1 millimeter in diameter. The intensity and relative proportion of 3D pixels in a collected volume can be used to quantify the power Doppler signal. Specific ultrasound software applications are utilized for such quantification. VOCAL (Virtual Organ Computer-aided Analysis) is one of them, and it generates three vascular indices: vascularization index (VI), flow index (FI), and a combination of the two, vascularization-flow index (VFI).
This study is a prospective cross sectional single-institute study carried out on 86 patients and conducted at the Department of Obstetrics and Gynecology, Minia maternity University Hospital, and Feto-Maternal Unit, Department of Obstetrics and Gynecology,, Egypt, from July 2021 to July 2022 All the patients included were examined using 2D gray scale US and 3D power Doppler.
- The enrolled patients were routinely followed up afterward and planned for surgery according to protocols.
- The patients who decided to withdraw, excluded.
- Taking a history, including maternal age, parity, and previous uterine scar. The gestational age was determined by the first day of the last menstrual period or by ultrasonography for individuals whose dates were unknown.
Ultrasound examination:
• Grey-scale trans-abdominal ultrasound: Used to assess both (A) fetal biometry, fetal well-being, congenital anomalies, amniotic fluid, placental site and grading, and any abnormalities. (B) 1- Any vascular lacunae (irregular vascular gaps) within the placenta giving it a ”Swiss cheese” look, absence of typical hypoechoic retroplacental zone, blood vessels or placental tissue bridging the uterine-placental boundary, myometrial-bladder interface, or crossing uterine serosa.
• 3D power Doppler showed the following: intraplacental hypervascularity, tortuous vascularity with ‘chaotic branching, basal view revealing vessels involving the serosa – bladder interface and measuring the vascular indices
• Surgical and histopathological diagnosis were obtained in all cases included in this study. Statistical analysis was done by which Ultrasound variables was compared with the histopathological diagnoses for all the patients.
• The parameters considered in analysis were 2D gray scale US and 3D power doppler finding and vascular indices (VI , FI and VFI) in diagnosis of PAS disorders for which cut off values predicting PAS and non PAS disorders were obtained.
Our results showed that 2D gray scale US finding as placental lacunae and serosa bladder interface hypervascularity, 3D power doppler criteria finding and vascular indices (VI , FI and VFI), may discriminate between PAS and non PAS disorders as their values were higher in PAS disorders than non PAS disorders.
Our results showed that 3D power doppler criteria (vascular bridging) had higher sensitivity and specificity (90.91% and 84.2%) respectively in diagnosis of MAP than 2D us criteria (Retroplacental Myometrial thickness ,Placenta lacunae, bladder-serosa interface hypervascularity ) which had sensitivity and specificity (78.18% and 83.87%),(87.9% and 83.87%),(83.3% and 87.1%) respectively .
In our study by comparing the AUCs of 2D US in diagnosis of MAP was 0.888 , VI was 0.890, FI was 0.745 , VFI was 0.917 , , the best variable to predict PAS disorders is VFI followed by VI then 2D US and lastly FI . This study showed that the use of three-dimensional sonography and power Doppler angiography can complement the conventional two-dimensional ultrasound in diagnosis and prediction of PAS disorders.