Cardiac MR imaging assessment following tetralogy of fallot repair.

Survivors of tetralogy of Fallot (TOF) repair constitute a large and growing population of patients. Although postsurgical outcome is generally favorable, as these patients move into adulthood, late morbidity is becoming more prevalent and the notion that TOF has been "definitively repaired" is increasingly being challenged. Recent evidence suggests that adverse long-term postsurgical outcome is related to chronic pulmonary regurgitation, right ventricular dilatation, and deteriorating ventricular function. Cardiac magnetic resonance (MR) imaging has been established as an accurate technique for quantifying ventricular size, ejection fraction, and valvular regurgitation. Cardiac MR imaging does not expose the patient to ionizing radiation and is therefore ideal for serial postsurgical follow-up. Familiarity with the anatomic basis of TOF, the surgical approaches to repair, and postrepair sequelae is essential for performing and interpreting cardiac MR imaging examinations. For example, awareness of the complications and sequelae that can occur will assist in determining when to intervene to preserve ventricular function and will improve long-term outcome. Technical facility is necessary to tailor the examination to the individual patient (eg, familiarity with non-breath-hold modifications that allow evaluation of young and less compliant patients). The radiologist can play an essential role in the treatment of patients with repaired TOF by providing noninvasive anatomic and physiologic cardiac MR imaging data. Further technologic advances in cardiac MR imaging are likely to bring about new applications, better normative data, and more examinations that are operator independent.

Fabry disease: renal sonographic and magnetic resonance imaging findings in affected males and carrier females with the classic and cardiac variant phenotypes.

OBJECTIVE: To describe the renal ultrasonography (US) and magnetic resonance imaging (MRI) findings in affected males and female carriers with the classic and cardiac variant phenotypes of Fabry disease (alpha-galactosidase A [alpha-Gal A] deficiency). METHODS: The renal US and MRI features of 76 classically affected males (aged 7-53 years), 40 female carriers from classically affected families (aged 18-66 years), and 6 males with the cardiac variant phenotype (aged 17-59 years) were reviewed by 3 blinded board-certified radiologists. The images were evaluated for the presence of cortical cysts, parapelvic cysts, renal atrophy, decreased cortical thickness, increased echogenicity (US only), and decreased corticomedullary differentiation (MRI only). The consensus findings were analyzed with respect to the patients' sex, age, Fabry genotype and phenotype, and renal function. RESULTS: MRI was more sensitive than US in detecting radiographic abnormalities. In the 76 classically affected males, the most common US abnormalities were cysts (36.9%; cortical cysts = 22.4%, parapelvic cysts = 14.5%), increased echogenicity (17.1%), and decreased cortical thickness (11.9%), whereas the most common MRI abnormalities were cysts (47.3%; cortical cysts = 28.9%, parapelvic cysts = 18.4%), loss of corticomedullary differentiation (43.4%), and decreased cortical thickness (7.9%). Among the 40 female carriers, common US abnormalities included cysts (20%; cortical cysts = 10%, parapelvic cysts = 10%) and increased echogenicity (7.5%), whereas MRI findings included decreased corticomedullary differentiation (40%) and cysts (37.5%; cortical cysts = 20%; parapelvic cysts = 17.5%). Renal US and MRI were normal in 5 classically affected males aged 12 years or younger and 2 female carriers aged 20 years or younger. Among the 6 male cardiac variants, abnormal US findings included cysts (66.3%; cortical cysts = 50%, parapelvic cysts = 16.3%) and increased echogenicity (33.3%), whereas MRI detected decreased corticomedullary differentiation in all (100%) and cysts in 83% (cortical cysts = 66.7%; parapelvic cysts = 16.3%). Serum creatinine levels were elevated (>1.2 mg/dL) in 40.8% and 15% of the classically affected males and female carriers with US and/or MRI abnormalities compared with 14.8% and 0%, respectively, who had elevated serum creatinine levels but no detectable radiographic abnormalities. There was no association of alpha-Gal A genotype with type or frequency of abnormalities in classically affected patients. CONCLUSIONS: Among classically affected males and female carriers, renal US and/or MRI abnormalities were detected in 64.5% and 60%, respectively. The occurrence and number of abnormalities increased with age in affected males and female carriers. Cysts, particularly parapelvic cysts, were more common and appeared earlier than in the general population. No renal abnormalities were detected in classically affected males or female carriers <12 years or <20 years of age, respectively. Five of the 6 males with the later-onset milder cardiac variant phenotype had loss of corticomedullary differentiation on MRI. Renal imaging abnormalities were more frequent in older patients with elevated serum creatinine levels, regardless of alpha-Gal A genotype or Fabry phenotype.

The infant skull: a vault of information.

The art of interpreting skull radiographs is slowly being lost as trainees in radiology see fewer plain radiographs and depend more heavily on computed tomography and magnetic resonance imaging. Nevertheless, skull radiographs still provide significant information that is helpful in finding pathologic conditions and appreciating their extents. Abnormalities in the skull may be reflected as variations in the density, size, and shape of the skull, as well as skull defects. Skeletal dysplasias may manifest as a generalized decrease in calvarial density (hypophosphatasia, osteogenesis imperfecta), a generalized increase in calvarial density (osteopetrosis), or a focal increase in density (frontometaphyseal dysplasia). Diffusely decreased or increased calvarial density is usually associated with a process that affects the entire skeleton. Therefore, correct differentiation among these dysplasias depends on other concurrent features. Decreased size of the cranial vault at birth generally implies an underlying insult to the brain, including fetal alcohol syndrome and the so-called TORCH infections (toxoplasmosis, rubella, cytomegalovirus infection, herpes simplex). Macrocephaly may result from skeletal dysplasia or an increase in the intracranial volume (eg, due to underlying anomalies of the brain such as hydrocephalus).

Growth restriction in children with type B Niemann-Pick disease.

OBJECTIVES: To compare growth of children with type B Niemann-Pick disease (NPD) with disease variables including genotype, organomegaly, bone age, and serum insulin-like growth factor-1 (IGF-1). STUDY DESIGN: A cross-sectional analysis of growth was performed in 23 children and adolescents with enzymatically and genotypically confirmed NPD. Liver and spleen volumes were measured by quantitative computed tomography and skeletal age by a wrist radiograph. RESULTS: The mean Z scores for height and weight were -1.24 (29th percentile) and -0.75 (34th percentile). The mean liver and spleen volumes were 2.06 and 13.46 times normal for weight, respectively. Skeletal age was delayed by an average of 2.5 years, and serum IGF-1 level was at or below the 2nd percentile in 8 of 12 patients. Short stature and low weight were significantly correlated with large organ volumes, delayed bone age, and low IGF-1 levels. In contrast to patients with other mutations, individuals homozygous for the DeltaR608 mutation had normal height and weight, markedly less hepatosplenomegaly and bone age delay, and normal IGF-1 levels. CONCLUSIONS: Abnormal linear growth and delayed skeletal maturation are common in children and adolescents with type B NPD; however, homozygosity for DeltaR608 is associated with normal growth.

Changes in upper extremity position cause migration of peripherally inserted central catheters in neonates.

OBJECTIVE: The migration of peripherally inserted central catheters (PICCs) from the superior or inferior vena cava into the right atrium can pose a significant risk of lethal pericardial effusion and tamponade secondary to myocardial perforation. Arm movement has been reported to cause displacement of the catheter tip toward the heart and lead to ventricular tachycardia in adults. The objective of this study was to investigate whether adduction or abduction at the shoulder and flexion or extension at the elbow affect the position of PICCs placed via upper limb veins. We also hypothesized that arm movements can be used to reposition malpositioned catheters. METHODS: A total of 280 radiographs of 60 neonates with PICCs inserted via upper limb veins from July 2000 through June 2001 were reviewed. Differences in catheter tip position as a result of abduction versus adduction at the shoulder, flexion versus extension at the elbow, and combination changes in arm posture were determined by measurements in paired radiographs. Correction of malpositioned catheters was attempted in 10 patients by using arm movements without any alterations at the site of insertion. RESULTS: Arm movements were associated with significant displacement of catheters. Catheters that were placed via the basilic or axillary vein migrated toward the heart with adduction of the arm, whereas those that were placed via the cephalic vein moved away from the heart with adduction. Flexion of the elbow displaced catheters that were placed in the basilic or cephalic vein below the elbow toward the heart but did not have any effect on catheters that were placed via the axillary vein. For catheters that were placed in the basilic vein, simultaneous shoulder adduction and elbow flexion caused the greatest movement toward the heart (15.11 +/- 1.22 mm). We were able to reposition correctly inappropriately placed catheters in 9 of 10 patients by using arm movements. CONCLUSIONS: Arm movements significantly affect the position of the tip of the PICCs. Prevention of catheter migration into the right atrium requires radiographic determination of vein of insertion and monitoring of catheter tip position with upper extremity in position of maximum inward movement of catheter for that vein. Arm movements can be used to correct the malpositioned catheters.

Infantile leukemia presenting with cholestasis secondary to massive pancreatic infiltration.

We present a 10-week-old infant who presented with cholestasis. Biliary obstruction secondary to massive pancreatic infiltration was demonstrated by ultrasound. A diagnosis of acute lymphoid leukemia was confirmed. Enlargement of the pancreas is unusual both in this age group and in leukemia. Infantile leukemia, although rare and usually not associated with gastrointestinal presentations, should be considered as a cause of pancreatic enlargement and neonatal cholestasis.

MR cholangiography in the evaluation of neonatal cholestasis: initial results.

PURPOSE: To retrospectively analyze prospective magnetic resonance (MR) cholangiographic interpretations of findings and compare them with clinical outcome and to determine the accuracy of MR cholangiography in depicting extrahepatic biliary atresia and helping to distinguish it from other causes of neonatal jaundice. MATERIALS AND METHODS: Twenty-six infants (15 male, 11 female; median age, 2 months) underwent MR cholangiography with a 1.5-T MR imaging unit. Original interpretations were compared with clinical outcome. Statistical analysis was performed to determine the accuracy of MR cholangiography in depicting extrahepatic biliary atresia. Equivocal cases and any cases lost to follow-up were excluded. RESULTS: Findings in six of 26 infants were interpreted as normal, and none of five patients (one lost to follow-up) had biliary atresia or other surgical lesions; two were abnormal but not suggestive of biliary atresia (one false-negative finding); 12 were consistent with biliary atresia (three false-positive findings); four demonstrated a choledochal cyst; and two were equivocal. MR cholangiography accuracy was 82% (19 of 23); sensitivity, 90% (nine of 10); and specificity, 77% (10 of 13) for the detection of extrahepatic biliary atresia, with a positive predictive value of 75% (nine of 12) and a negative predictive value of 91% (10 of 11). CONCLUSION: Results of this study found that MR cholangiography is 82% accurate, 90% sensitive, and 77% specific for depicting extrahepatic biliary atresia. Contrary to previous reports, false-positive and false-negative findings occur at MR cholangiography.

Pediatric ribs: a spectrum of abnormalities.

The manifestations of many congenital and acquired conditions can be seen in the ribs of children. Normal variants are usually clinically insignificant; they are occasionally palpated at clinical examination or detected incidentally at chest radiography. Signs of abnormality can appear in the ribs as variations in number, size, mineralization, and shape. These changes can be focal or generalized. Abnormalities detected in the ribs may be the initial indication of previously unsuspected systemic disease. The ribs can yield important diagnostic clues in the work-up of patients with congenital bone dysplasias, acquired metabolic diseases, iatrogenic conditions, trauma (especially child abuse), infection, and neoplasms. Routine evaluation of the ribs on every chest radiograph is important so that valuable diagnostic data will not be overlooked. The diagnostic information obtained from evaluation of the ribs can help tailor the radiologic and laboratory studies that may be necessary to complete a patient's diagnostic work-up.