Cynthia K. Rigsby

R2* imaging of transfusional iron burden at 3T and comparison with 1.5T

To determine normative R2* values in the liver and heart at 3T, and establish the relationship between R2* at 3T and 1.5T over a range of tissue iron concentrations.

Correction of Extrahepatic Portal Vein Thrombosis by the Mesenteric to Left Portal Vein Bypass

Objective:The goal of this study was to determine the effectiveness of mesenteric vein to left portal vein bypass operation (MLPVB) in correcting extrahepatic portal vein thrombosis (EHPVT) in children. The treatment of idiopathic EHPVT has been primarily palliative, whereas MLPVB restores hepatic portal flow in patients with EHPVT. Methods:Thirty-four children with symptomatic EHPVT underwent surgery with intent to perform MLPVB and were followed for up to 7 years. MLPVB was successful in 31 patients (91%), all of whom maintain patent vein grafts and have symptomatic relief of EHPVT in follow-up. All patients had complete relief from gastrointestinal bleeding. Patients with hypersplenism had significant increases in platelet and leukocyte counts and reduction in spleen size. Superior mesenteric vein flow increased from 119 ± 66 mL/min before bypass to 447 ± 225 mL/min (P < 0.0001) after surgery. Postoperative blood flow in the bypass graft expressed as a fraction of calculated ideal portal flow for size correlated inversely with age (P < 0.001). Left-portal vein diameter increased from 2.6 ± 1.6 mm to 7.3 ± 2.4 mm 2 years after surgery (P < 0.002). Liver volume increased from 703 ± 349 cm3 to 799 ± 351 cm3 1 week after surgery (P < 0.001). Prothrombin time improved to normal in all patients 1 year after surgery. Conclusions:MLPVB provides excellent relief of symptoms in children with idiopathic EHPVT and results in liver growth and normalization of coagulation parameters. This surgery is corrective and should be done at as early an age as possible.

Outcomes and risk factors for failure of radiologic treatment of biliary strictures in pediatric liver transplantation recipients

Posttransplantation biliary strictures occur in 5–34% of the pediatric liver transplant patients and are conventionally managed by interventional radiological techniques. The aim of this manuscript is to assess the outcomes of patients with biliary strictures treated by percutaneous dilatation at our institution. Included in the study were 35 children with posttransplant biliary strictures that were treated with percutaneous dilatation and stenting. Initial dilation and biliary stent placement was accomplished in all patients without complications requiring surgical intervention. Recurrent strictures developed in 23 (66%) of 35 patients. The recurrence rate was 45% for anastomotic strictures, 90% for intrahepatic strictures, and 100% for those with both an anastomotic and intrahepatic component. Seven patients required revision of the choledochojejunostomy, 5 of them with a successful outcome and 2 requiring retransplant. Five patients were treated with retransplantation without surgical revision. Patients with an intrahepatic or a “combined” stricture were less likely to have a successful outcome after radiologic treatment. In conclusion, the radiological treatment of biliary strictures with balloon dilation and stenting can be performed successfully with minimal complications avoiding the need for surgical correction in many cases. Liver Transpl 12:821–826, 2006.

Intramural Coronary Length Correlates With Symptoms in Patients With Anomalous Aortic Origin of the Coronary Artery

BACKGROUND Anomalous aortic origin of a coronary artery (AAOCA) from the opposite sinus of Valsalva is a rare congenital anomaly with the potential for myocardial ischemia and sudden death. This review evaluated our series of AAOCA patients, who underwent coronary artery unroofing, to test our hypothesis that the intramural length of the anomalous coronary artery correlates with symptoms. METHODS A retrospective analysis of symptoms, preoperative imaging (computed tomography and magnetic resonance imaging), intraoperative assessment, perioperative course, and follow-up were reviewed. RESULTS From 2005 to 2010, 27 patients (70% male) underwent surgical AAOCA repair. Mean age was 14.3±12 (range, 6 to 52) years. In 25 patients with right AAOCA, 14 had chest pain and 4 had syncope. Both patients with left AAOCA had chest pain. AAOCA unroofing was done in 25 and side-to-side anastomosis in 2. The intramural coronary artery length measured intraoperatively correlated with preoperative symptoms (symptoms=10±3.58 mm, no symptoms=5.2±1.5 mm, p<.002), as did preoperative imaging measurements (symptoms=7.8±2.8 mm, no symptoms=5.3±0.8 mm, p<.001). Preoperative imaging strongly predicted the intraoperative measurement (r=0.81, p=0.00001). There were no deaths, significant morbidity, or recurrence of symptoms. CONCLUSIONS Coronary unroofing for AAOCA is a safe method of enlarging the coronary orifice and eliminating the intramural course. Symptomatic patients had a longer intramural course than asymptomatic patients, as assessed by preoperative imaging and intraoperative measurements. These results may have important clinical implications in determining indications for operation.

Safety and Efficacy of Pressure-Limited Power Injection of Iodinated Contrast Medium Through Central Lines in Children

OBJECTIVE The purpose of this study was to evaluate the safety and efficacy of pressure-limited power injection of contrast medium through central lines for pediatric body CT examinations. SUBJECTS AND METHODS All patients with a central line who were referred for body CT examinations requiring an i.v. contrast agent were prospectively evaluated. The power injector was pressure limited to 25 psi (172 kPa). A standard dose of 2 mL/kg of iodinated contrast medium was power-injected through the central line. Two pediatric radiologists scored all examinations on a scale of 1 (poor) to 5 (superior) for adequacy of contrast enhancement. Regression and receiver operating characteristic analyses were performed. RESULTS The subjects were 63 patients 0.3-22 years old. Nineteen of these patients had tunneled lines, 18 had ports, and 26 had peripherally inserted central catheters. There were no complications related to power injection. Regression analysis showed a significant association between patient weight and contrast enhancement adequacy score (p < 0.001), higher patient weights yielding lower contrast enhancement adequacy scores. Receiver operating characteristic analysis showed a weight cutoff of 30 kg as a reasonable predictor of adequacy of contrast enhancement. For patients weighing 30 kg or more, the average contrast enhancement score was 2.4 (suboptimal to adequate). For patients weighing less than 30 kg, the average contrast enhancement score was 3.4 (adequate to good). CONCLUSION Pressure-limited power injection through central lines in children is safe. The contrast enhancement obtained with 25 psi (172 kPa) pressure-limited injection is acceptable only for patients who weigh less than 30 kg.

Tracheal reconstruction in children with unilateral lung agenesis or severe hypoplasia.

BACKGROUND Infants with congenital tracheal stenosis may also have unilateral lung agenesis or severe lung hypoplasia. The purpose of this review is to evaluate our results with these patients and compare their presentations and outcomes to those of tracheal stenosis patients with two lungs. METHODS Our database was queried for patients undergoing tracheal stenosis repair since 1982. Patients were divided into two groups based on pulmonary anatomy of single lung (SL = unilateral lung agenesis or severe hypoplasia) or two lungs (BL = bilateral lungs) and analyzed to compare presentation and outcomes. RESULTS From 1982 to 2008, 71 patients had tracheal stenosis repair. Bilateral lungs were present in 60 patients; 9 patients had an absent (4) or severely hypoplastic (5) right lung, and 2 patients had an absent left lung (SL = 11). Age at repair was similar between groups; median age 0.42 years in the SL group (mean 0.80 +/- 1.0 years) versus 0.37 years in the BL group (mean 0.91 +/- 2.1 years, p = not significant [ns]). In the SL group 8 of 11 (73%) were intubated preoperatively versus 15 of 60 (25%) in the BL group (p = 0.004). In the SL group 4 of 11 (36%) patients had pulmonary artery sling versus 20 of 60 (33%) of BL patients (p = ns). In the SL group 2 of 11 (18%) versus 14 of 60 (23%) in the BL group had intracardiac anomalies requiring simultaneous repair (p = ns). Procedures included pericardial tracheoplasty (2 vs 26), tracheal autograft (4 vs 16), slide tracheoplasty (3 vs 8), and tracheal resection (2 vs 10). Overall mortality (operative and late) was 2 of 11 (18%) SL versus 10 of 60 (17%) BL (p = ns). Median postoperative length of stay was 43 days SL (mean 48.6 +/- 40) versus 30 days BL (mean 52.2 +/- 65) (p = ns). The incidence of postoperative tracheostomy (SL group) was 0 of 3 for slide tracheoplasty and 5 of 8 for the other techniques (p = 0.12). CONCLUSIONS Despite the increased severity of pathology and increased critical presentation of tracheal stenosis patients with unilateral lung agenesis or severe hypoplasia, outcome measures of mortality and length of stay were similar to patients with two lungs. The incidence of associated pulmonary artery sling (1 of 3) and intracardiac anomalies (1 of 4) was similar. Unilateral lung agenesis or severe hypoplasia should not preclude operative repair of tracheal stenosis. Slide tracheoplasty is our current procedure of choice for these infants.

Novel therapeutic approaches in the treatment of children with hepatoblastoma.

Hepatoblastoma is the most common liver tumor diagnosed in children. Children with persistently unresectable disease, metastatic disease at presentation, recurrent disease, or slowly declining alpha-fetoprotein levels are at high risk for recurrence, exhibit an extremely poor prognosis, and are in desperate need of novel therapeutic agents and strategies. Four high-risk patients were treated. One patient with a local recurrence was treated with irinotecan followed by orthotopic liver transplant. Three patients were treated with tandem high-dose chemotherapy (HDT) with autologous stem cell rescue (two with primary metastatic disease and one with recurrent disease). All three of the patients treated with HDT had relapse (two of them subsequently received irinotecan); the remaining patient underwent surgical resection of a solitary recurrent pulmonary metastasis. Irinotecan demonstrated significant antitumor effects in all three treated patients and was well tolerated. None of the three patients treated with HDT remained disease-free, although the patient who underwent surgical resection of a solitary recurrent pulmonary metastasis remains disease-free 6 years from diagnosis. Further exploration of the use of irinotecan is warranted in high-risk patients with hepatoblastoma.

Is the frontal radiograph alone sufficient to evaluate for pneumonia in children

BackgroundIn our cost- and radiation-conscious environment, the feasibility of performing only a frontal radiograph for the diagnosis of pneumonia in children needs to be reassessed.ObjectiveTo determine the diagnostic efficacy of the frontal radiograph alone in comparison to the frontal and lateral combined radiographs for the radiographic diagnosis of pneumonia in children.Materials and methodsThree radiologists retrospectively and independently reviewed the frontal radiographs alone and separately reviewed the frontal and lateral radiographs of 1,268 children referred from the emergency room for chest radiographs. A majority interpretation of at least two radiologists for the frontal views alone was compared with majority interpretation of the frontal and lateral combined views for the radiographic diagnosis of pneumonia. “Pneumonia” was defined as a focus of streaky or confluent lung opacity.ResultsFor the radiographic diagnosis of pneumonia, the sensitivity and specificity of the frontal view alone were 85% and 98%, respectively. For the confluent lobar type of pneumonia, the sensitivity and specificity increased to 100%.ConclusionWhen the frontal view alone yields a diagnosis of confluent lobar pneumonia, this is highly reliable. However, nonlobar types of infiltrates will be underdiagnosed in 15% of patients using the frontal view alone. The clinical impact of these radiographically underdiagnosed pneumonias needs to be assessed prior to implementing the practice of using only frontal radiographs for diagnosing pneumonia.

Advanced flow MRI: emerging techniques and applications.

Magnetic resonance imaging (MRI) techniques provide non-invasive and non-ionising methods for the highly accurate anatomical depiction of the heart and vessels throughout the cardiac cycle. In addition, the intrinsic sensitivity of MRI to motion offers the unique ability to acquire spatially registered blood flow simultaneously with the morphological data, within a single measurement. In clinical routine, flow MRI is typically accomplished using methods that resolve two spatial dimensions in individual planes and encode the time-resolved velocity in one principal direction, typically oriented perpendicular to the two-dimensional (2D) section. This review describes recently developed advanced MRI flow techniques, which allow for more comprehensive evaluation of blood flow characteristics, such as real-time flow imaging, 2D multiple-venc phase contrast MRI, four-dimensional (4D) flow MRI, quantification of complex haemodynamic properties, and highly accelerated flow imaging. Emerging techniques and novel applications are explored. In addition, applications of these new techniques for the improved evaluation of cardiovascular (aorta, pulmonary arteries, congenital heart disease, atrial fibrillation, coronary arteries) as well as cerebrovascular disease (intra-cranial arteries and veins) are presented.

Primary Resection of Kommerell Diverticulum and Left Subclavian Artery Transfer

BACKGROUND A Kommerell diverticulum (KD) is an aneurysmal remnant of the dorsal fourth aortic arch. This can be an independent cause of tracheoesophageal compression. We previously reported resection of the KD with left subclavian artery transfer to the left carotid artery for recurrent symptoms in patients with a right aortic arch, left ligamentum, and retroesophageal left subclavian artery after prior ligamentum division. In 2001 we began resecting the KD and transferring the left subclavian artery to the left carotid artery in selected patients as a primary operation. METHODS From 2001 to 2011, 20 patients have had primary excision of a Kommerell diverticulum. Diagnosis was with computed tomographic scan (n = 14) or magnetic resonance imaging (n = 6) and bronchoscopy. Sixteen patients had a right aortic arch and 4 had a double aortic arch (right arch dominant). All patients were approached through a left thoracotomy. Fifteen patients had simultaneous division and reimplantation of the left subclavian artery into the left carotid artery. RESULTS Mean age at operation was 9.1 ± 6.5 years (range 1.5 to 29.1 years). Symptoms included cough, wheezing, stridor, dysphagia, and dyspnea on exertion. Selection criteria included KD greater than 1.5 times the size of the left subclavian artery and posterior pulsatile compression of the trachea on bronchoscopy. There were no complications related to subclavian artery transfer. No patient required a blood transfusion. No patient had a recurrent laryngeal nerve injury or chylothorax. The mean hospital stay was 4.3 ± 2.5 days. All patients had resolution of their preoperative airway and esophageal symptoms. CONCLUSIONS In selected patients with a vascular ring we now recommend resection of the associated Kommerell diverticulum and transfer of the retroesophageal left subclavian artery to the left carotid artery as a primary procedure. This strategy requires comprehensive and precise preoperative imaging with either computed tomography or magnetic resonance imaging.