Stuart C. Morrison

MR imaging of pediatric cerebral abnormalities

Surgicalne hundred sixteen magnetic resonance (MR) imaging studies from 105 pediatric patients with a variety of cerebral abnormalities were reviewed to determine the diagnostic efficacy of MR in the pediatric population. All subjects tolerated the MR procedure well, although sedation was necessary for younger children. Compared with CT, MR proved to be advantageous in detection and characterization of the pathology in 23 of 105 patients, especially when the abnormality was located along the base of the brain and midline, or when it involved primarily the white matter. Intracranial calcification was the one abnormality not detected with MR although dense calcifications could be seen as areas of low signal intensity. Some characteristics of various pathological entities were compared in an attempt to differentiate among abnormalities in the same anatomical location: craniopharyngioma from optic chiasm and hypothalamic glioma, cystic glioma from arachnoid cyst, and chronic subdural hematoma from subdural hygroma. The lack of ionizing radiation in MR is of particular interest in pediatric neuroradiology since radiation is of special concern in the young age group.

Neonates with hypoplastic left heart syndrome have ultrasound evidence of abnormal superior mesenteric artery perfusion before and after modified Norwood procedure.

Objective: To a) describe superior mesenteric artery resistive index, as an estimate of perfusion, before and after modified Norwood; and b) assess incidence of diastolic flow reversal in the superior mesenteric artery before and after modified Norwood. Design: Prospective observational trial. Setting: Children’s hospital pediatric intensive care unit. Patients: Ten newborns with hypoplastic left heart syndrome. Interventions: Ultrasound documentation of superior mesenteric artery diastolic flow direction and measurement of superior mesenteric artery resistive index 24–48 hrs before and 24–48 hrs after modified Norwood. Measurements and Main Results: Seven males and three females were enrolled. There was no change between the superior mesenteric artery resistive index pre- vs. postoperatively—0.99 (95% confidence interval, 0.85, 1.12) vs. 1.07 (95% confidence interval, 1.0, 1.15) (p = .13). Incidence of retrograde diastolic blood flow in the superior mesenteric artery was not different pre- vs. postoperatively (70% vs. 50%, p = .41). No patients developed necrotizing enterocolitis and all survived to hospital discharge. Conclusions: Ultrasound measurements in neonates with hypoplastic left heart syndrome suggest that superior mesenteric artery perfusion, as measured by resistive index, is impaired. Superior mesenteric artery diastolic flow reversal is common before and immediately after modified Norwood.

Azygos continuation of the inferior vena cava: demonstration by NMR imaging.

Azygos continuation of the inferior vena cava was diagnosed by magnetic resonance (MR) imaging in a patient with a right tracheobronchial angle mass. The characteristic findings included a dilated azygos vein and absence of the hepatic segment of the inferior vena cava. Advantages of MR imaging in evaluation of anomalies of the cava are discussed.

MR imaging of the skull base

Fifty-four patients with abnormalities primarily involving the base of the skull were evaluated by magnetic resonance (MR) imaging. The results were compared with information obtained by other radiologic studies, primarily X-ray CT. On MR imaging, better anatomic definition of soft tissues in the deep compartments of the nasopharynx was achieved through the high level of tissue contrast discrimination and lack of bone artifacts. The parapharyngeal fat plane, separating pterygoid from pharyngeal musculatures, was consistently demonstrated. However, the inability of MR to image compact bone proved to be a major drawback where bony detail was required. In general, MR imaging demonstrated 100% sensitivity to abnormalities involving the posterior compartment (clivus and craniovertebral junction) and was least valuable in the evaluation of the anterior compartment (orbits, cribiform plate, and sinuses).

CT appearance of renal infarct.

A case is presented in which a histologically proven focal infarct of the kidney appeared as a low density mass lesion on computed tomography (CT). In patients with appropriate history, infarction should be included in the differential diagnosis of an area of low CT attenuation within the kidney.

Adult with an interstitial deletion of chromosome 10 [del(10)(q25.1q25.3)]: Overlap with Coffin-Lowry Syndrome

We recently evaluated a mentally retarded 48 year old man found to have a cytogenetic deletion of chromosome 10 [46,XY,del(10) (q25. 1q25.3)]. Of interest, he shares many clinical findings with those described in Coffin-Lowry syndrome (CLS). These include severe mental retardation, short stature and a coarse facial appearance with widely spaced eyes, and patulous lips. He also had an extra transverse hypothenar crease, a finding that is seen in CLS. Furthermore, he has characteristic radiographic hand findings described in 95% of patients with CLS. The CLS gene, located at Xp22. 2, has recently been identified, and mutations in the Rsk-2 gene have been identified in several CLS patients. Rsk2 is part of a gene family implicated in cell cycle regulation through the mitogen-activated protein (MAP) kinase cascade. None of the currently recognized components of this pathway maps to the region deleted in our patient, nor are we able to identify any likely candidate genes in the deleted region, although several G protein coupled receptors have been cloned from the region. This patients findings have some overlap with those seen in CLS, suggesting that a gene involved in MAP kinase signaling may be present in the deleted region of chromosome 10q25.1-25.3. Patients with a phenotype consistent with CLS, but lacking a family history suggestive of an X-linked disorder, should be evaluated with chromosome analysis paying particular attention to the region 10q25.

Primary sclerosing cholangitis: CT findings.

Computed tomographic (CT) findings in six cases of primary sclerosing cholangitis (PSC) are described. Computed tomographic findings correlate with cholangiographic findings and show ductal dilatations and distortions in the porta hepatis and in the liver parenchyma. The CT features are round, oval, or irregular, sometimes branching, focal dilatations of the biliary tree. When subtle, irregular dilatations of the intrahepatic biliary tree are observed, the presumptive diagnosis of sclerosing cholangitis can be made from CT. Confirmation of this diagnosis with cholangiography is essential in all patients. Recognition of this entity by a noninvasive method will avoid long delays in diagnosis and will expedite the use of the more definitive procedures such as endoscopic retrograde cholangiopancreatography, percutaneous transhepatic cholangiography, or liver biopsy.

The accuracy of chest radiographs in the detection of congenital heart disease and in the diagnosis of specific congenital cardiac lesions

BackgroundCongenital heart disease (CHD) is a significant cause of morbidity and mortality in pediatric patients. Traditional teaching holds that specific types of CHD can be diagnosed on the chest radiograph (CXR) through pattern recognition.ObjectiveTo determine the accuracy of radiologists in detecting CHD on the CXR.Materials and methodsThis study was a blinded retrospective review of chest radiographs from 281 patients (<12 years) by five pediatric radiologists from three institutions. Thirteen groups were evaluated that included 12 categories of CHD and a control group of patients without heart disease. Radiographs were assessed for heart size, heart and mediastinal shape and vascularity. Clinical information, angiography, echocardiograms and surgery were used as the gold standard for definitive diagnosis.ResultsThe average accuracy of the five readers in distinguishing normal from CHD patients was 78% (range of 72% to 82%). The overall measure of accuracy in distinguishing specific congenital cardiac lesions among 13 groups of patients was 71% (range of 63% to 79%).ConclusionCXR alone is not diagnostic of specific cardiac lesions, with a low accuracy of only 71%. We believe that less emphasis should be placed on the use of radiographs alone in diagnosing specific congenital cardiac lesions.

Clinical and locus heterogeneity in brachydactyly type C

Brachydactyly type C is characterized by shortness of the second and fifth middle phalanges and the first metacarpal. It is inherited as an autosomal dominant trait, and is noted for its widely variable clinical phenotype both within and between families. In most families involvement is limited to the hands. However, in some families additional skeletal and non-skeletal findings have been reported. We report on 12 affected members from a 5 generation kindred that segregates a brachydactyly type C phenotype. All affected individuals had shortness principally affecting the second and fifth phalanges and first metacarpal. However, the metacarpal-phalangeal profile indicated that other digital elements were short as well. In addition, one affected individual had a bilateral Madelung deformity, but none had foot involvement. No other non-skeletal findings cosegregated with brachydactyly in this family. Recently, a gene for brachydactyly type C has been localized to 12q24. This was done by studying a large kindred first reported by Haws [1963], which manifests both hand and foot anomalies. Here we present linkage data which excludes the 12q24 locus in our kindred, indicating locus heterogeneity as one explanation for the interfamilial variability described in brachydactyly type C.

Intramedullary osteosclerosis. A report of the clinicopathologic features of five cases.

The clinicopathologic features of five patients with intramedullary osteosclerosis are presented. The patients, ranging in age from 8 to 52 years (mean 31 years), all presented with pain referred to the lower extremity. The sclerotic lesions involved the entire lower extremity in 1 patient, mid-tibial shaft in 2, distal tibia in 1, and distal fibula in 1 patient. The histopathologic features of intramedullary osteosclerosis overlap with those of melorheostosis. The differential diagnosis also includes a spectrum of entities, each characterized by osteosclerosis and each of which is compared and contrasted to the cases presented.