Brigitte Stöver

Low-dose spiral CT: applicability to paediatric chest imaging.

Background. Spiral CT of the chest is an imaging technique with unequivocal indications and proven higher sensitivity and specificity than conventional chest X-rays. However, particularly in children, attempts should be made to reduce radiation exposure to a minimum. Objective. To evaluate whether a low-dose technique in spiral CT scanning results in adequate diagnostic information. Materials and methods. In a prospective study, 27 children (range 3 weeks to 14 years, mean 7 years) underwent a low-dose CT examination of the chest for various indications. The tube energy was 12.5 mAs (n = 5), 25 mAs (n = 17), 50 mAs (n = 3), or 75 mAs (n = 2) per slice. Two radiologists evaluated, in consensus, the CT scans with respect to their diagnostic value and comparison was made with 20 standard-dose chest CT examinations of adults (175 mAs per slice, mean age 56 years) with respect to technical image quality (noise and artefacts). In a second part of the study, dose measurements were carried out by means of exposing thermoluminescent dosimeters attached to a water/air phantom simulating a childs chest. Results. All low-dose CT scans were of diagnostic image quality and no additional studies were necessary. The average image noise was significantly higher than in standard-dose CT examinations (SD 39.5 compared with 12.5 for unenhanced soft tissue, P < 0.01), but did not hinder accurate diagnosis. Artefacts were exclusively due to patient motion. Radiation exposure per slice was approx. 4 mGy at 25 mAs and 34 mGy at 250 mAs, regardless of slice thickness. Conclusions. For all indications in paediatric CT scanning of the chest, low-dose technique provides adequate image quality without loss of diagnostic information. The radiation exposure is approximately 5–20 % of a standard-dose CT.

Brachydactyly type C caused by a homozygous missense mutation in the prodomain of CDMP1

Brachydactyly type C (BDC) is characterized by shortening of the middle phalanges of the index, middle, and little finger with hyperphalangy, usually of the index and middle finger. Heterozygous mutations of the cartilage derived morphogenetic protein‐1 (CDMP1) resulting in a loss of function have been reported in BDC. We here describe a large kindred with a semi‐dominant form of BDC and pronounced ulnar deviation of the second and third digits. In this family a novel homozygous missense mutation was identified (517A > G) changing methionine to valine at amino acid position 173. The mutation is located within a highly conserved seven amino acid region of the prodomain of CDMP1. Hand radiographs of heterozygous mutation carriers showed mild shortening of the metacarpals IV and V; a finding confirmed by the analysis of their metacarpophalangeal profiles (MCPPs). The mutation described here points toward an important function of the prodomain for the folding, secretion, and availability of biologically active CDMP1.

3-D ULTRASOUND QUANTIFICATION OF NEONATAL CEREBRAL VENTRICLES IN DIFFERENT HEAD POSITIONS

We determined the influence of head position on lateral ventricular cerebral volume in low-birth-weight infants by three-dimensional (3-D) ultrasound (US). Thirty-nine neonates were examined prospectively in a controlled and blinded study. We used a freehand 3-D US system to acquire data sets after head positioning for 3 h on left and right side in random order. The borders of the lateral ventricles were marked in stored cross-sections. Volumes were calculated as mean of duplicate measurements. Median volume of lateral cerebral ventricles was 1.03 (quartiles 0.78-1.36) mL. Median left ventricular volume was slightly larger than right one (p = 0.13). Down-side lateral ventricles showed smaller volumes than up-side positioned ventricles (p < 0.01). Freehand 3-D US allows quantification of small volumes as neonatal lateral cerebral ventricles. Head position influences the lateral cerebral ventricle volume in low-birth-weight infants.

Colour-coded duplex sonography in the diagnostic assessment of vascular complications after kidney transplantation in children

Background. Vascular complications are a major cause of dysfunction or transplant loss in children. Arterial or venous occlusion, transplant renal artery stenosis (TRAS) and some arteriovenous (AV) fistula require rapid detection and prompt intervention. The present study was performed to determine the accuracy of colour Doppler sonography (CDS) in the early and late phase after renal transplantation and to correlate the results with angiographic and intraoperative findings. Objective. CDS is the preferred imaging modality with a high diagnostic accuracy for follow-up of renal transplantation in children. The indication for angiography should be established on the basis of the CDS diagnosis. Materials and methods. In 87 children (mean age 10.9 years, range 2–17), 423 CDS examinations were performed after renal transplantation. Angiography was performed in 17 cases; surgery was necessary in 16 patients. Results. CDS correctly identified 8/8 arterial or venous occlusions and 7/7 TRAS. The only false positive diagnosis of TRAS was due to misinterpretation of an iliac artery stenosis. Six AV fistulae were diagnosed by CDS. The overall positive predictive value of CDS was 94 % in this study. Conclusion. CDS is a noninvasive, non-radiation producing imaging modality with a high diagnostic accuracy. It is the method of choice in the assessment of vascular complications after renal transplantation in children.

Colonic pneumatosis intestinalis in preterm infants: different to necrotising enterocolitis with a more benign course?

Abstract Necrotising enterocolitis (NEC) is the predominant immaturity-associated disease of the bowel in the preterm neonate and leads to substantial mortality and long-term morbidity. Diagnostic features of NEC include, apart from the clinical presentation, laboratory and radiological parameters. Pneumatosis intestinalis (PI) on abdominal radiographs is regarded as a criterion of definitive proof for this disease entity. The objective of this presentation is to link the topographic pattern of PI to the clinical course in cases of suspected NEC. We report two cases of radiological appearance of colonic PI indicative of NEC without associated laboratory and/or macroscopic evidence of the disease, and with minor clinical symptoms only. Data from animal studies indicate that decreased blood supply to the small bowel is associated with more extensive bowel damage as compared to impaired colonic perfusion. Therefore the topographical distribution of PI might be a more specific sign as the general presence or absence of PI. Conclusion The topographical pattern of pneumatosis intestinalis may be predictive of the clinical course of inflammatory bowel disease in preterm infants.

Haemangiomatosis in children : value of MRI during therapy

MRI findings of 18 examinations of six children with haemangiomatosis and one with extended arteriovenous malformation are reported. Structures involved were the liver, liver and lung, periorbital area and the thigh. Response to interferon therapy, in particular, was assessed. With MRI the disease can be characterized and the extent of the lesions and size of the haemangiomas measured. Coronal views provide excellent demonstration of the involved structures in liver and lung haemangiomatosis. Two children showed response to interferon therapy with a reduction in lesion size and subsequently in number. Signal intensity decreased slightly on T2-weighted images. During treatment, however, no definitive fibrotic zones were seen. Following complete regression, signal intensity of the liver parenchyma was homogeneous in both weightings, that is, no fibrotic areas were visible 18 months after the beginning of treatment. Two children showed no response and one child died from congestive cardiac failure. The periorbital haemangioma was reduced in size and the lesion in the thigh might be classified as an arteriovenous malformation. In children MRI can replace CT as it is a reliable imaging modality for diagnosing haemangiomatosis and monitoring therapy.

Value of RARE-MRI sequences in the diagnosis of lymphangiomatosis in children

Three patients suffering from extensive cavernous lymphangiomatosis are presented here. They were examined by MRI using RARE-MR hydrography (rapid acquisition with relaxation enhancement) as well as conventional spin-echo sequences. RARE sequences, which depict each fluid-filled lymphatic space, can be used for screening. RARE-sequences help to shorten investigation time, particularly in cases involving the skeleton. The imaging strategy can be changed according to the results of this sequence. It may be performed prior to spin-echo sequences and facilitates follow-up investigations. RARE sequences distinguish between lymphangiomatosis and hemangiomatosis, or a combination of the two.

Asymmetric evolution of pulmonary interstitial emphysema in a preterm newborn infant

In preterm newborn infants, intermittent mandatory ventilation may cause pulmonary interstitial emphysema (PIE). This may even occur under nasal continuous positive airway pressure (CPAP). However, with nasal CPAP, baroand volutrauma are assumed to affect both lungs equally. We report on a preterm infant on nasal CPAP who developed bilateral PIE that aggravated on the left side while showing spontaneous resolution on the right side.

CT-Untersuchungen beim Kind: Technik und Indikationen

ZusammenfassungDie Technik der Spiral-CT hat für die Diagnostik von Thorax und Abdomen beim Kind erhebliche Vorteile. Kurze Scanzeiten erlauben Untersuchungen in einer Atemphase ebenso wie solche eines Organs bei ruhig atmendem Kind, ohne daß eine Sedierung erforderlich ist. Zudem sind insbesondere Thoraxuntersuchungen und in begrenzterem Umfang auch solche des Abdomens mit reduziertem Röhrenstrom durchführbar. Dies führt zu einer Reduktion der Strahlenexposition bis zu einem Drittel der Dosis, ohne daß diagnostisch wichtige Informationen verlorengehen. Die low-dose-Technik ist in der Diagnostik der parenchymatösen Erkrankungen der Lunge, bei Raumforderungen des Mediastinums und Malformationen der großen Atemwege einsetzbar. Im Bereich des Abdomens muß aus Gründen der Strahlenexposition die Indikation zum Einsatz der Methode im Vergleich zur MRT im Einzelfall geprüft werden. Die korrekte technische Durchführung der Spirale, ausreichende Dosierung des Kontrastmittels und korrekte Handhabung des Scan-Delay sowie Rekonstruktionen aus dem gesamten Datensatz führen zu einem erheblichen Informationsgewinn durch den Einsatz der Methode.SummaryTechnical advantages of spiral technology are of great usefulness in diagnostic imaging of thorax and abdomen in children. The rapid imaging time allows the examination of an entire organ while scanning with breath holding or while the child is quietly breathing, resulting in a decreased need for sedation. In addition especially examinations of the chest an to some extend CT-investigations of the abdomen are performed with reduced radiation dose achieved by reducing the tube loading. Radiation dose reduction of 70% is possible without loss of relevant diagnostic information. Spiral low-dose CT in pediatric chest imaging is useful in evaluating parenchymal lung diseases, mediastinal masses and central airway malformations. Whether abdominal helical CT can be replaced by MRI has to be decided in each individual case. When an exact protocol is used, sufficient contrast material given, scan-delay optimized and postprocessing reconstructions are performed, usefull additional diagnostic informations are obtained by the method.

Neonate with spinal hypoplasia on T12 and a localized vertebral malformation on L4.

We report a case of a neonate with sectional narrowing of the spinal cord on the level of T12 to L2 and a deformed vertebral body on a different level, L4. In previously described cases of sectional spinal dysgenesis, the vertebral and spinal cord malformations are usually found on the same level. Our case may represent a new variant of spinal dysgenesis. (J Child Neurol 2001;16:619-621).