Volume 11 Issue 1 (February) - Australasian Society for Ultrasound ...

REVIEWS
Scanning the journals
Antenatal diagnosis of placenta previa accreta in patients
with previous caesarean scar
Paparaj R P et al. J Obstet Gynaecol Res 2007; 33: 431–37.
This Malaysian team studied 21 patients with previous caesarean
scar, partial or total placenta praevia diagnosed after
28 weeks gestation. Gray scale B-mode transabdominal
sonography and colour Doppler transvaginal scans were
done on each patient. Criteria suggestive of placenta praevia
accreta on gray scale were:
n Loss of retroplacental hypoechoic zone;
n Multiple lakes representing dilated vessels extending
from the placenta through the myometrium;
n Thinning or disruption of the uterine serosa-bladder wall
interface; and
n Focal elevation of tissue with placental echogenicity
beyond uterine serosa.
n Color and power Doppler criteria included:
n Dilated vascular channels with diffuse lacunar flow;
n Abnormal vessels linking placenta to bladder; and
n Dilated subplacental vascular channels with pulsatile
venous flows over the cervix.
At least one of these features was found in seven
patients (33%) with a mean gestational age of 29 weeks at
diagnosing.
Hypervascularity linking placenta to bladder in color
Doppler was the most reliable sign (7/7) with the presence of
multiple lakes seen with grayscale being less reliable (6/7).
They found that the transabdominal approach was
superior to the transvaginal.
This is an important study highlighting the importance of
ultrasonographic diagnosis of this maternal life-threatening
condition.
Prenatal ultrasound diagnosis of vasa praevia and analysis
of risk factors
Baulies S, et al. Prenat Diag 2007; 27: 595–99.
And another article on a potentially lethal condition, this
time of the fetus. All cases of vasa praevia were diagnosed
during the second trimester scan and so they had no prenatal
deaths related to this condition. They also emphasise the
importance of checking placental cord insertion at the fetal
morphology scan, as marginal or velamentous insertions are
risk factors for vasa praevia.
Paradoxical movement of abdominal contents – a real-time
sonographic finding indicating a congenital diaphragmatic
hernia
Sista AK and Filly RA. J Ultrasound Med 2007;
26: 1617–19.
The authors describe paradoxical movement of the intra
abdominal contents in congenital diaphragmatic hernia. The
video clips available at www.jultrasoundmed.org illustrate
the movement of intra-abdominal contents during fetal
breathing, especially on inspiration.
Real time observation and recording in this difficult
diagnostic area might be invaluable in arriving at a correct
diagnosis.
Prevention of spontaneous preterm birth: the role of sonographic
cervical length in identifying patients who may
benefit from progesterone treatment
Romero R, et al. Ultrasound Obstet Gynaecol 2007;
30: 675–86.
This editorial is an exhaustive review of the topic. It merits
reading because it reinforces the fact that measuring cervical
length is a valuable part of the mid trimester ultrasound
examination. Preterm birth is still an enigma. We can help
provide information as to the likely risk for preterm delivery
in primigravidae when we check cervical lengths at the fetal
morphology scan. It is reassuring that ASUM guideline D2
includes sonographic evaluation of the cervix at the fetal
morphology scan.
A Review of findings in fetal cardiac section drawings part
1: the four-chamber view
Jeanty P, et al. J Ultrasound Med 2007; 26: 1601–10.
It is not often that we see an article in an ultrasound journal
with no sonographic images. But this presentation had as
its goal a review of some common and some rare fetal heart
anomalies using drawings to illustrate the main features.
Fetal cardiac scanning is difficult and any help the
general sonographer can get is welcome. This is the first of
a three-part series and is well worth reading carefully. If you
come across an unusual finding on the four-chamber view it
could help with the differential diagnosis before referral to
the paediatric cardiologist.
Are metastases really hypovascular in the arterial phase?
Murphy-Lavalee J, et al. J Ultrasound Med 2007;
26: 1545–56.
The question is a good one. Received wisdom from contrastenhanced
CT and MR work would seem to suggest that liver
metastases are hypovascular. This work from Toronto using
contrast-enhanced ultrasonography (CEUS) shows that most
hepatic metastases show arterial hypervascularity and rapid
complete wash-out. The technique might be helpful in
differentiating mestastases from primary liver tumours. And
in the future CEUS might have a place in management of
patients after drug therapy.
Comparing differential tissue harmonic imaging with tissue
harmonic and fundamental gray scale imaging of the liver
Chiou SY, et al. J Ultrasound Med 2007; 26: 1557–63.
While I did not understand the physics (especially the
inclusion of the Khokhlov – Zabolotskaya – Kuznetsov
equation) it appears that differential tissue harmonic
imaging (DTHI) and tissue harmonic imaging do better than
fundamental sonography for liver scanning. In particular, the
lateral resolution of DTHI was superior and better penetration
was achieved. This argues well for improvements in image
quality and may be especially useful in obese patients.
The Gleaner
ASUM Ultrasound Bulletin 2008 February 11 (1)
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