Matthias Mühler

Studies on the time frame for ossification of the medial epiphysis of the clavicle as revealed by CT scans.

The authors retrospectively analyzed 629 CT images of patients aged between 15 and 30 years produced during multiple trauma diagnostics at the Unfallkrankenhaus Berlin. For the purposes of this study, the authors reliably determined the ossification status of the medial epiphysis of the clavicle in 556 cases, using the classification of stages by Schmeling et al. In both sexes, stage 2 was first noted at age 15. In male patients, the earliest occurrence of stage 3 was noted at age 17, in female patients at age 16. Stage 4 was first achieved by both sexes at age 21. Stage 5 was first noted in female patients at age 21 and in male patients at age 22, which is 4 or 5 years earlier than was observed by a comparable study using conventional radiographs. The partial-volume effect in computed tomography using the thick slice scanning mode was discussed as a possible explanation for this early visualization. The question of how slice thickness affects the age intervals between ossification stages identified by CT examinations should be examined in additional studies.

Unilateral borderline fetal ventriculomegaly as inherited anatomical variant depicted by fetal and maternal magnetic resonance imaging

Fetal borderline ventriculomegaly presents a challenge to all ultrasound examiners in terms of both differential diagnosis and counseling. In addition to ruling out other extracerebral abnormalities and offering karyotyping, magnetic resonance imaging (MRI) of the fetal brain is nowadays commonly performed as part of the diagnostic work-up1–6. In borderline ventriculomegaly MRI can provide information on associated structural anomalies, the presence of hemorrhage or leukomalacia and cortical abnormalities otherwise not detectable on ultrasound examination. We report on a case with fetal unilateral borderline ventriculomegaly in which the family history raised the suspicion of an inherited disorder without clinical significance as shown by parental MRI. The 36-year-old patient (gravida 2 para 1) was referred for a genetic sonogram at 22 weeks’ gestation. In addition to an echogenic intracardiac focus we found a 10.5mm unilateral borderline ventriculomegaly of the right side of the brain (Figure 1a). Intracranial and extracranial anatomy was otherwise normal. Following amniocentesis, chromosomal analysis revealed a normal karyotype (46,XY) and no signs of fetal infection. We suggested performing fetal MRI at 25 weeks’ gestation and on a later occasion if the ventriculomegaly persisted in the follow-up ultrasound scan. MRI was performed in the supine position with a body phased-array coil on a 1.5-T scanner (Siemens Sonata, Erlangen, Germany) using either T2-half Fourier acquisition single-shot turbo spin echo (HASTE) sequence (time to repeat (TR) 1260, time to echo (TE) 72, α 180◦, number of excitations (NEX) 1, slice thickness 3 mm and 4 mm, field of view (FOV) 300 × 300, matrix 256 × 256) in transverse, sagittal and coronal planes, and a T1-gradient echo sequence (TR 160, TE 6, α 70◦, NEX 1, slice thickness 4 mm, FOV 300 × 260, matrix 128 × 111) in the transverse plane. MRI confirmed the finding of unilateral borderline ventriculomegaly (Figure 1b) on the right side. In addition, there was mild asymmetry of the pallium in the parietooccipital region as well as mildly flattened gyration on the right side. The hypointense cortical layer could easily be distinguished from the white matter and appeared normal on the T2-HASTE images. No intermediate layer was detected, making a migratory disease very unlikely. When explaining these findings to the mother, she unexpectedly reported that similar ultrasound results with respect to unilateral ventricular enlargement had been encountered in her previous pregnancy. Nevertheless, her 5-year-old daughter had shown normal neurological development. Because the mother had conceived the first child with Figure 1 Imaging at 25 weeks’ gestation. (a) Ultrasound image showing mild unilateral ventriculomegaly on the right side. (b) Magnetic resonance image confirming the ultrasound findings and additionally showing a slight thinning of the pallium in the parieto-occipital region and a slightly asymmetrical gyration. The most external, hypointense layer of the pallium represents the normal cortical layer.

Endoleak After Endovascular Aneurysm Repair: Evaluation of a Single-Acquisition CTA Protocol Using a Prebolus

Purpose To investigate a single-acquisition computed tomographic angiography (CTA) protocol using a prebolus injection technique to visualize the stent-graft lumen and endoleak after endovascular aneurysm repair (EVAR). Methods Of 162 EVAR patients referred for CTA over a 2-year period, 18 (15 men; mean age 66.4 years) with an endoleak met the study inclusion criteria, which included constant endoleak size and scans using 3 different CT protocols at least once during follow-up: monophasic CTA (C1), biphasic CTA (C2.1 and C2.2), and single-acquisition CTA using a prebolus (PB). All CTA examinations were performed with the same overall volume of contrast medium (120 mL) and were started manually using a bolus-tracking technique. Attenuation was measured within the aortic lumen proximal to the stent prosthesis (Ao) and within the endoleak itself (EL). Results Mean attenuation ranged between 200 (C2.2) and 313 HU (C2.1) within Ao and between 172 (C2.2) and 235 HU (C2.1) within the endoleak. The attenuation differences between Ao (C1) and Ao (PB), as well as between Ao (C2.1) and Ao (PB), were not statistically significant, while the attenuations of Ao (C2.2) and Ao (PB) differed significantly (p<0.001), with higher attenuation in PB. Compared to EL (PB), none of the mean EL attenuation values (C1, C2.1, and C2.2) differed significantly. Conclusion This prebolus CTA protocol combines late-phase attenuation of a biphasic image acquisition protocol for endoleak visualization with high opacification of the stent lumen without exposing the patient to radiation twice.

P10.03: Magnetic resonance imaging as an alternative to amnioinfusion in suspected fetal renal agenesis

Primary renal agenesis is not a diagnostical challenge as oligohydramnios is almost always present at the time of the anomaly scan. In contrast secondary (or progressive) renal agenesis (e.g. in multicystic dysplastic kidney) is frequently missed as kidneys are present but smaller in size and they tend to vanish with advancing gestational age. We present a case of a 24-year-old woman, gravida 1 para 0, referred to our center at 24+3 weeks’ gestation for suspicion of IUGR and oligohydramnios. Ultrasound showed a small multicystic left kidney. The right kidney could not be visualized. In view of the challenging scan conditions and the fact that normal kidneys were documented on previous exams a fetal MRI was requested. This case stresses the possibility of MCDK and other forms of cystic renal dysplasia in fetuses with oligohydramnios – even if a normal urinary tract was visualized on earlier exams. From our experience MRI as an alternative to amnioninfusion was decisive in confirming the diagnosis.