D. Dean Potter

3 Tesla MR imaging provides improved contrast in first-pass myocardial perfusion imaging over a range of gadolinium doses

PURPOSE To compare myocardial enhancement during first-pass myocardial perfusion imaging at 3.0 Tesla (T) and 1.5T. MATERIALS AND METHODS First-pass myocardial perfusion imaging was performed on twelve normal subjects at 3T and 1.5T using an interleaved notched saturation recovery gradient echo pulse sequence. Subjects received either 0.10 mmol/kg for both scans (group 1), 0.075 mmol/kg for both scans (group 2), or 0.075 mmol/kg for the 3T scan and 0.10 mmol/kg for the 1.5T scan (group 3). RESULTS Contrast enhancement was significantly greater at 3T than at 1.5T for the 12 subjects whether enhancement was normalized to baseline signal intensity (2.58 +/- 0.76 vs. 1.52 +/- 0.37, p < 0.0001) or to noise (57.6 +/- 19.7 vs. 14.7 +/- 7.8, p < 0001). For each of the three groups, contrast enhancement was significantly greater at 3T versus 1.5T (p < 0.0001, p < 0.001, p < 0.008 when normalized to baseline signal; p < 0.0001 for all groups when normalized to noise). CONCLUSION 3T improves contrast in first-pass myocardial perfusion imaging at either 0.10 mmol/kg or 0.075 mmol/kg.

The Role of Defective Mismatch Repair in Small Bowel Adenocarcinoma in Celiac Disease

Celiac disease is associated with an increased risk of small bowel adenocarcinoma. The aims of this study were to investigate the molecular basis, assess outcomes, and identify clinicopathologic characteristics of small bowel adenocarcinoma in celiac disease. Retrospective case control cohort study of all celiac disease patients treated at our institution for small bowel adenocarcinoma and matched control patients with sporadic small bowel adenocarcinoma from July 1960 to November 2002. Mismatch repair (MMR) status was accessed by testing tissue for microsatellite instability (MSI) and for hMLH1 and hMSH2 protein expression. Over a 40-year time period, 18 patients with small bowel adenocarcinoma and celiac disease were treated at the Mayo Clinic. One celiac disease patient was excluded. High-frequency MSI (MSI-H) was identified in 8 of 11 (73%) and 2 of 22 (9%) available small bowel adenocarcinoma specimens in the celiac disease and control groups, respectively. In the celiac disease group, MSI-H was associated with loss of hMLH1 and hMSH2 in 6 and 1 specimens, respectively. Loss of hMLH1 occurred in both control tumors. Stage was associated with celiac disease status (P = 0.018), and 78% of controls were stage III or IV compared with 47% of celiac disease patients. Overall, survival was better (P = 0.025) in the celiac disease group compared with stage-matched controls. Celiac disease patients with small bowel adenocarcinoma had a high incidence defective MMR (73%) compared with controls and had better survival compared with stage-matched controls. In addition, celiac disease patients presented more frequently with early-stage small bowel adenocarcinoma. The better survival and earlier presentation of small bowel adenocarcinoma in celiac disease appears to be biologically associated with defective MMR.

The natural history of familial adenomatous polyposis syndrome: A 24 year review of a single center experience in screening, diagnosis, and outcomes

PURPOSE Understanding the natural history of Familial Adenomatous Polyposis (FAP) will guide screening and aid clinical management. METHODS Patients with FAP, age ≤20years presenting between 1987 and 2011, were reviewed for presentation, diagnosis, extraintestinal manifestations, polyp burden, family history, histology, gene mutation, surgical intervention, and outcome. RESULTS One hundred sixty-three FAP patients were identified. Diagnosis was made by colonoscopy (69%) or genetic screening (25%) at mean age of 12.5years. Most children (58%) were asymptomatic and diagnosed via screening due to family history. Rectal bleeding was the most common (37%) symptom prompting evaluation. Colon polyps appeared by mean age of 13.4years with >50 polyps at the time of diagnosis in 60%. Cancer was found in 1 colonoscopy biopsy and 5 colectomy specimens. Family history of FAP was known in 85%. 53% had genetic testing, which confirmed APC mutation in 88%. Extraintestinal manifestations included congenital hypertrophy of the retinal pigment epithelium (11.3%), desmoids (10.6%), osteomas (6.7%), epidermal cysts (5.5%), extranumerary teeth (3.7%), papillary thyroid cancer (3.1%), and hepatoblastoma (2.5%). Six patients died secondary to FAP. CONCLUSIONS Clinical presentation and manifestations in pediatric FAP are variable. We suggest an individualized patient-oriented screening algorithm that allows for earlier screening and appropriate management.

Fifty-three–year experience with pediatric umbilical hernia repairs

PURPOSE The aim of this study was to evaluate the long-term surgical and patient-reported outcomes of pediatric umbilical hernia (UH) repairs. METHODS A retrospective review of all children (<18 years old) who underwent UH repair at Mayo Clinic-Rochester in the last half century was done. Follow-up was obtained by mailed survey. RESULTS From 1956 to 2009, 489 children (boys, 251; girls, 238) underwent a primary UH repair. The mean age was 3.9 years (range, 0.01-17.8 years). Complicated UHs that required emergent repair (n = 34, or 7%) included recurrent incarceration (22), enteric fistula (7), strangulation (4), and evisceration (1). Mean UH size was 1.3 cm (range, 0.2-7.0 cm), varying by operative indication (1.0 cm emergent vs 1.5 cm elective repairs, P = .008) and decade of repair (2.2 cm, 1950s-60s vs 1.3 cm, 1990s-2000s; P = .001). Postoperative morbidity (2%) consisted of superficial wound infection (7), hematoma (3), and seroma (1). With a 66% survey response rate and mean follow-up of 13.0 years (range, 0-53.8 years), 8 (2%) patients experienced a recurrence. Most patients reported satisfaction (90%) with the cosmetic appearance of their umbilicus and are pain free (96%). CONCLUSION Pediatric UH repairs have low morbidity and recurrence rates. Most patients are satisfied and pain free. Importantly, complicated UHs were more likely to be associated with smaller defects; therefore, parental counseling for signs of incarceration is recommended even in small defects.

Pediatric chronic ulcerative colitis: does infliximab increase post–ileal pouch anal anastomosis complications?

BACKGROUND Total proctocolectomy with ileal pouch anal anastomosis (IPAA) is a common surgical approach to chronic ulcerative colitis (CUC). Preoperative use of Infliximab (IFX) has raised concern of increased postoperative complications. We sought to compare outcomes of pediatric patients (≤ 18 years) who were treated with IFX before IPAA to those who did not. METHODS Patients (≤ 18 years of age) who underwent IPAA from 2003 to 2008 for CUC were included, and their records were retrospectively reviewed for preoperative medications, operative technique, and 1-year postoperative complications (leak, wound infection, small bowel obstruction, pouchitis). Subjects were divided into 2 groups--those who received IFX preoperatively and those who did not. RESULTS Eleven patients received IFX preoperatively, and 27 children did not. All complications following IPAA were more frequent in the IFX group compared to controls (55% vs 26%). Small bowel obstruction was significantly higher in the IFX group (55% vs 7%). Long-term complications occurred in 64% of the IFX group and 61% of the controls. CONCLUSION Children that were treated with IFX prior to IPAA suffered twice as many postoperative complications. Long-term outcomes are similar. Currently, we recommend colectomy with end ileostomy for patients that receive IFX within 8 weeks of colectomy for CUC.

Adenocarcinomas of the jejunum and ileum: a 25-year experience.

Adenocarcinomas of the jejunum and ileum are rare gastrointestinal malignancies. Because few large published experiences exist, we reviewed patients with jejunal and ileal adenocarcinoma treated at our institution over the last 25 years. Between January 1976 and December 2001, 77 patients had an operation for a jejunal or ileal adenocarcinoma. Records were retrospectively reviewed for patient, tumor, and treatment variables. Factors affecting disease recurrence and patient survival were investigated. Fifty-two of the adenocarcinomas (67%) occurred in the jejunum and 25 occured in the ileum (33%). Mean patient age was 63 ±14 years. Segmental bowel resection was performed in 50 patients (65%) with curative intent. Palliative operative procedures including resection or bypass were performed in 27 patients (35%). One (1%) patient had stage I, 18 (23%) stage II, 19 (25%) stage III, and 39 (51%) stage IV adenocarcinoma at diagnosis. Postoperatively, 12 patients had palliative and 18 adjuvant chemotherapy (n 5 30), radiation therapy (n = 1), or combination treatment (n = 7). Median patient survival was 19 months. Sixty-six percent of patients who had a curative operation had a tumor relapse. Tumor stage had a highly significant effect (P < 0.0001) on median survival (72 months for stage I and II, 30 months for stage III, and 9 months for stage IV disease). In multivariate analysis of patients having curative treatment, tumor recurrence (P < 0.0001), stage (P < 0.0002), and weight loss (P < 0.001) were significant negative prognostic indicators. Most patients with adenocarcinoma of the jejunum or ileum present with advanced disease. Tumor stage, disease recurrence, and weight loss predicted patient outcome following a curative operation. Early recognition of these tumors requires a high index of suspicion.

Biventricular Finite Element Modeling of the Acorn CorCap Cardiac Support Device on a Failing Heart

BACKGROUND The Acorn CorCap Cardiac Support Device (CSD; Acorn Cardiovascular Inc, St. Paul, MN) is a woven polyester jacket that is placed around the heart and designed to reverse the progressive remodeling associated with dilated cardiomyopathy. However, the effects of the Acorn CSD on myofiber stress and ventricular function remain unknown. We tested the hypothesis that the Acorn CSD reduces end-diastolic (ED) myofiber stress. METHODS A previously described weakly coupled biventricular finite element (FE) model and circulatory model based on magnetic resonance images of a dog with dilated cardiomyopathy was used. Virtual applications of the CSD alone (Acorn), CSD with rotated fabric fiber orientation (rotated), CSD with 5% prestretch (tight), and CSD wrapped only around the left ventricle (LV; LV-only) were performed, and the effect on myofiber stress at ED and pump function was calculated. RESULTS The Acorn CSD has a large effect on ED myofiber stress in the LV free wall, with reductions of 55%, 79%, 92%, and 40% in the Acorn, rotated, tight, and LV-only cases, respectively. However, there is a tradeoff in which the Acorn CSD reduces stroke volume at LV end-diastolic pressure of 8 mm Hg by 23%, 25%, 30%, and 7%, respectively, in the Acorn, rotated, tight, and LV-only cases. CONCLUSIONS The Acorn CSD significantly reduces ED myofiber stress. However, CSD wrapped only around the LV was the only case with minimal negative effect on pump function. Findings suggest that LV-only CSD and Acorn fabric orientation should be optimized to allow maximal myofiber stress reduction with minimal reduction in pump function.

Low-dose dobutamine cardiac magnetic resonance imaging with myocardial strain analysis predicts myocardial recoverability after coronary artery bypass grafting

OBJECTIVES Accurate prediction of recovery of dysfunctional myocardium would optimize risk/benefit analysis among patients with coronary artery disease and decreased ventricular function. Tissue-tagged magnetic resonance imaging permits quantitative assessment of changes in ventricular function and may improve the prediction of myocardial recovery after coronary artery bypass grafting. METHODS Thirteen patients underwent preoperative and postoperative stress magnetic resonance imaging with strain analysis at rest with 5 and 10 microg x kg(-1) x min(-1) dobutamine. Two-dimensional strain analysis was performed on a single midventricular short-axis image divided into 6 regions for each patient (n = 78). Regional minimum principal, circumferential, and radial strain values were calculated at each stress level. Regional changes in postoperative strain were correlated with changes in preoperative dobutamine stress by means of logistic regression. Receiver operating characteristic curves were created to determine the accuracy of preoperative dobutamine stress for the prediction of postoperative myocardial recoverability. RESULTS Minimum principal, circumferential, and radial strain values at 5 and 10 microg of dobutamine differed significantly from baseline strains (P < .05). Receiver operator characteristic curves found minimum principal strain to be 75% accurate for prediction of recoverability at both stress levels. Circumferential strain was 72% and 70% accurate at 5 and 10 microg, respectively, whereas radial strain was 77% and 64% accurate at 5 and 10 microg, respectively. CONCLUSIONS Dobutamine-stressed tissue-tagged magnetic resonance imaging with strain analysis is feasible to quantitatively predict myocardial recoverability after coronary artery bypass grafting. Further study is required to determine the optimal strain parameter for predicting myocardial recoverability after surgical revascularization.

A coupled biventricular finite element and lumped-parameter circulatory system model of heart failure

Numerical modelling of the cardiovascular system is becoming an important tool for assessing the influence of heart disease and treatment therapies. In the current study, we present an approach for modelling the interaction between the heart and the circulatory system. This was accomplished by creating animal-specific biventricular finite element (FE) models, which characterise the mechanical response of the heart, and by coupling them to a lumped-parameter model that represents the systemic and pulmonic circulatory system. In order to minimise computation time, the coupling was enforced in a weak (one-way) manner, where the ventricular pressure–volume relationships were generated by the FE models and then passed into the circulatory system model to ensure volume conservation and physiological pressure changes. The models were first validated by tuning the parameters, such that the output of the models matched experimentally measured pressures and volumes. Then the models were used to examine cardiac function and the myofibre stress in a healthy canine heart and a canine heart with dilated cardiomyopathy. The results showed good agreement with experimental measurements. The stress in the case of cardiomyopathy was found to increase significantly, while the pump function was decreased, compared to the healthy case. The total runtime of the simulations is lesser than that of many fully coupled models presented in the literature. This will allow for a much quicker evaluation of possible treatment strategies for combating the effects of heart failure, especially in optimisation schemes that require numerous FE simulations.

Treatment of Appendicitis in Neutropenic Children

BACKGROUND Appendicitis in the neutropenic patient places the clinician in a precarious position; balancing the timing and risks of surgery and the risk of an uncontrolled infectious source in the abdomen. METHODS Multi-center retrospective review from 2000 to 2010 of appendicitis occurring in patients with neutropenia secondary to chemotherapy. Patient demographics and surgical outcomes were tracked. RESULTS There were 11 patients, mean age of 11 y (3-17 y); six were male. Mean weight was 46.9 kg (18.1-72.6 kg). Mean body mass index was 20.9 kg/m(2) (16.8-27.3 kg/m(2)). There were five acute lymphocytic leukemias, four acute myeloblastic leukemias, one T-Cell lymphoma, and one Ewings sarcoma. Mean presenting white blood cell count was 1900 (0.2-4.4). Average absolute neutrophil count was 900 (0.00-2.6). Computed tomography scan was used in all patients. Appendectomy was performed within 24 h of presentation in all patients, three were perforated. Mean time to first feeding was 1 d (range, 0-5 d), goal feeds at 3 d (range, 1-6 d ). Mean length of stay from appendicitis was 4 d. CONCLUSION Early appendectomy for appendicitis in neutropenic patients appears to be tolerated well with a low risk of surgical complications.