Douglas H. Jamieson

Does the transition zone reliably delineate aganglionic bowel in Hirschsprung's disease?

Background: Knowledge of the extent of aganglionic bowel is important for preoperative planning of trans-anal surgery in patients with Hirschsprung’s disease (HD). Objective: To evaluate the accuracy of the transition zone, as identified by contrast enema study, for identifying the extent of aganglionic bowel. Materials and methods: A total of 32 patients with preoperative contrast enema studies and pathologic identification of aganglionic extent were reviewed. Two pediatric radiologists independently reviewed the contrast enema studies. The radiographic transition zone was compared to the pathological extent of aganglionic bowel. Results: Radiologist agreement of the site of transition zone on contrast enema was 90.6%. The concordance between the radiographic transition zone and pathologic extent of aganglionic bowel was 62.5%. The subgroup of patients with long-segment HD revealed a concordance of only 25%. Conclusion: Contrast enema delineation of the transition zone in HD needs to be regarded with caution. This is especially true in long-segment disease, where knowledge of the extent of aganglionic bowel is most crucial to surgical planning.

Atelectasis on pediatric chest CT : comparison of sedation techniques

Background. A change in practice at our institution resulted in increased use of anesthesia for CT scan of the chest in children who required sedation. Objective. To determine whether there is a difference in the frequency or severity of pulmonary atelectasis on CT scan in children sedated by anesthesiologists compared with children sedated by radiologists using intravenous pentobarbital. Materials and methods. Retrospective blinded review of 60 CT scans of the chest performed in 41 children. Forty-one studies in children sedated by radiologists (median age 29 months) were compared with 19 studies in children sedated by anesthesiologists (median age 25 months). Results. Atelectasis sufficient to obscure pulmonary metastases was shown in 5 of 41 (12 %) radiology sedations and 13 of 19 (68 %) anesthesiology sedations (P < 0.01). Higher grades of atelectasis were recorded in children under anesthesia (P < 0.01). Conclusion. Atelectasis is more frequent and more severe in children undergoing general anesthesia compared with intravenous pentobarbital sedation. Consideration should be given to the use of forced inspiration in children anesthetized for CT scan of the chest.

Traumatic pseudoaneurysms of the liver and spleen in children: is routine screening warranted?

BACKGROUND Although blunt injury to the spleen and liver can lead to pseudoaneurysm formation, current surgical guidelines do not recommend follow-up imaging. Controversy exists regarding the clinical implications of these traumatic pseudoaneurysms as well as their management. METHODS Retrospective review of children treated nonoperatively for isolated blunt liver and spleen trauma between 1991 and 2008 was undertaken. Patient demographics, grade of injury, and follow-up Doppler ultrasound results were obtained. RESULTS Three hundred sixty-two children were identified. One hundred eighty-six of them had splenic injuries, and 10 (5.4%) developed pseudoaneurysms. They were associated with grade III (3/39 [8%]) and grade IV (7/41 [17%]) injuries. In 7 patients, the pseudoaneurysm thrombosed spontaneously. Angiographic embolization was required in 2 children, and one underwent emergency splenectomy for delayed hemorrhage. Of the 176 patients who had liver injuries, 3 (1.7%) developed pseudoaneurysms. All 3 were associated with grade IV injuries (3/11 [27%]). One child underwent early embolization, while 2 developed delayed hemorrhage requiring emergent treatment. CONCLUSIONS Pseudoaneurysm development after blunt abdominal trauma is associated with high-grade splenic and liver injuries. Routine screening of this group of patients before discharge from hospital may be warranted because of the potential risk of life-threatening hemorrhage.

Os odontoideum: a significant radiographic finding.

Os odontoideum can lead to instability of the atlantoaxial joint and places the spinal cord at significant risk for acute catastrophic events after minor trauma or chronic neurological change. We present two cases of os odontoideum in pediatric patients that were not appreciated at earlier remote imaging but were, in retrospect, detectable. One patient presented with an acute spinal cord injury. Incorporating assessment of dens integrity into the evaluation algorithm for all pediatric cervical spine studies should lead to early detection of os odontoideum lesions and allow referral to appropriate clinical spinal services for evaluation, surveillance and possible surgery to prevent future complications.

The use of CT in the development and implementation of a preoperative protocol to aid in pedicle screw placement during scoliosis surgery.

Scoliosis surgical constructs, using pedicle screws, provide increased fixed penetrable points for rod attachment. This allows improved curve correction and increases hardware stability. We have implemented a multidetector CT evaluation of the spine with post-process image manipulation to aid pedicle screw placement for deformity correction. Preoperative scanning was done with a Philips Brilliance 16 multislice CT scanner. The created image dataset provided valuable preoperative information regarding pedicle morphology, suitability for screw placement and preoperative screw planning. Projected intraoperatively, the images increased the surgeon’s confidence during screw placement, especially in large deformities with severe rotation. Improving pre- and intraoperative pedicle information is a valuable tool in operative management of children with spinal deformity.

A review of congenital lung malformations with a simplified classification system for clinical and research use

PurposeCongenital lung abnormalities are rare malformations increasingly detected early by prenatal ultrasound. Whether management of these frequently asymptomatic lesions should be surgical or conservative is an unresolved issue. The necessary prospective studies are limited by the absence of a widely accepted practical classification system. Our aim was to develop a simple, clinically relevant system for classifying and studying congenital lung abnormalities.Materials and methodsWe based our proposed grouping on a detailed analysis of clinical, radiological, and histological data from well-documented cases, plus an extensive review of the literature.ResultsThe existence of hybrid lesions and common histological findings suggested a unified embryological mechanism—possibly obstruction of developing airways with distal dysplasia. Malformations could be classified by their anatomical and pathological findings; however, a system based on the prenatal ultrasound plus initial chest X-ray findings had greater clinical relevance: Group 1—Congenital solid/cystic lung malformation, Group 2—Congenital hyperlucent lobe, Group 3—Congenital small lung.ConclusionsPathological classification is academically important but is unnecessarily complex for clinical and research use. Our simple radiological-based system allows unambiguous comparison between the results of different studies and also guides the choice of necessary investigations specific to each group.

Focal hepatic lesions in neonates.

Sir, I read with interest the case report “Intrahepatic hematoma: hepatic lesion in a newborn with high α-fetoprotein level” [1]. The presented lesion, its anatomic location, and imaging appearance are typical of the ten focal hepatic lesions related to umbilical venous catheter (UVC) misplacement we presented in Dublin at the ESPR meeting [2]. A focal liver lesion and raised α-fetoprotein level certainly do raise concern for hepatoblastoma in a young infant. In a premature neonate with a liver insult, awareness of the potential for a raised α-fetoprotein, as described, is important. However, I do not accept lightly the exclusion of UVC misplacement as a cause for the presented lesion. Did the authors review all previous abdominal plain films to confirm a UVC tip placed above the diaphragm and thus in the inferior vena cava? We have sonographically documented a clinically functioning line with its tip in the hepatic parenchyma and have angiographic evidence of a catheter in the hepatic parenchyma rapidly draining injected contrast into the hepatic vein after a brief parenchymal blush. None of our ten lesions was prospectively diagnosed, two patients were excessively imaged because of concern about neonatal hepatoblastoma, and one died from a hepatic compartment syndrome diagnosed when the hepatic collection of TPN ruptured into the peritoneum. This is an under-appreciated condition about which it is difficult to find information in the published literature, although cases are to be found in review articles [3, 4], and eight cases of TPN ascites from liver erosion by UVCs have been reported in this journal [5]. We are now wiser and will hopefully get our experience published in the near future. Currently, in our neonatal ICU the sonographic appearance of the liver lesion, as presented in the case report, would have had Doppler evaluation to ensure no flow. A review of abdominal plain films would have revealed a misplaced UVC or UVC tip projecting over the hepatic parenchyma. We would have performed only follow-up sonography to document the expected resolution, usually to a small calcific focus. We would have confidently avoided CT from thyroid to gonads, sedation for MR and multiple aspiration and biopsy procedures. I am in full agreement with the authors’ conclusion that hepatic hematoma, or a focal hepatic lesion related to UVC placement, should be in the differential diagnosis of all neonatal hepatic lesions. In our study period of 14 months, among the ten focal hepatic lesions we discovered, no hepatoblastoma, no hemangioendothelioma and no mesenchymal hamartoma were diagnosed. It was by far the most common focal hepatic lesion in our NICU.