Pulmonary arterial hypertension in children: diagnosis using ratio of main pulmonary artery to ascending aorta diameter as determined by multi-detector computed tomography.

BACKGROUND: The ratio of the transverse diameter of the main pulmonary artery (MPA) to ascending aorta as determined at multi-detector CT is a tool that can be used to assess the pulmonary arterial size in cases of pulmonary arterial hypertension in children. OBJECTIVE: To establish a ratio of MPA to ascending aorta diameter using multi-detector CT imaging suggestive of pulmonary arterial hypertension in children. We hypothesize that a defined ratio of MPA to ascending aorta is identifiable on multi-detector CT and that higher ratios can be used to reliably diagnose the presence of pulmonary arterial hypertension in children. MATERIALS AND METHODS: We calculated the multi-detector CT ratio of MPA to ascending aorta diameter in 44 children with documented pulmonary arterial hypertension by right heart catheterization and in 44 age- and gender-matched control children with no predisposing factors for pulmonary arterial hypertension. We compared this multi-detector-CT-determined ratio with the MPA pressure in the study group, as well as with the ratio of MPA to ascending aorta in the control group. A threshold ratio value was calculated to accurately identify children with pulmonary arterial hypertension. RESULTS: Children with documented primary pulmonary arterial hypertension have a significantly higher ratio of MPA to ascending aorta (1.46) than children without pulmonary arterial hypertension (1.11). A ratio of 1.3 carries a positive likelihood of 34 and a positive predictive value of 97% for the diagnosis of pulmonary arterial hypertension. CONCLUSION: The pulmonary arteries were larger in children with pulmonary arterial hypertension than in a control group of normal children. A CT-measured ratio of MPA to ascending aorta of 1.3 should raise the suspicion of pulmonary arterial hypertension in children.

Main Pulmonary Artery-to-Ascending Aorta Diameter Ratio in Healthy Children on MDCT.

OBJECTIVE: This study was performed to ascertain whether the adult ratio of 1:1 of the diameter of the main pulmonary artery (MPA) to the diameter of the ascending aorta (AA) (referred to hereafter as the MPA-to-AA ratio) on MDCT is applicable to children. MATERIALS AND METHODS: Our hypothesis, which is based on experiential observation, is that the MPA-to-AA ratio would be higher than 1 in healthy children. A retrospective analysis of vessel calibers in a population of children without pulmonary hypertension who had undergone MDCT was performed. RESULTS: The MPA-to-AA ratio was statistically significantly higher in children of all ages than in adults. We would, therefore, submit that the normal MPA-to-AA ratio in children on MDCT is greater than 1 and closer to 1.09. CONCLUSION: The demonstration of an MPA segment that is slightly larger than the AA in children undergoing MDCT should not suggest a diagnosis of pulmonary arterial hypertension.

Perianal disease in pediatric Crohn disease: a review of MRI findings.

Perianal complications of Crohn disease are a common occurrence in children and can result in significant morbidity when not accurately characterized prior to surgical intervention. MRI is an excellent imaging modality for the evaluation of perianal inflammatory bowel disease - allowing characterization and detailed description of perianal fistulas. MRI has many advantages over other imaging modalities for the pediatric patient. Radiologists will benefit from a sophisticated understanding of perianal anatomy, the classification of perianal fistulas, the advantages MRI offers in characterization of perianal fistulas as well as the common and incidental findings that are important in the MRI evaluation of perianal inflammatory bowel disease in children. Perianal fistulas are found at a high rate in pediatric referrals and are more commonly found in male patients.

Systematic review of current guidelines, and their evidence base, on risk of lactic acidosis after administration of contrast medium for patients receiving metformin.

PURPOSE: To systematically review evidence about the relationship between metformin administration and the use of iodinated contrast medium and risk of lactic acidosis (LA) and to assess the quality of five current guidelines for use of contrast medium in patients who are taking metformin. MATERIALS AND METHODS: A search strategy was developed by using search termsrelated to metformin, contrast media, and LA. Searches were conducted in MEDLINE (Ovid), all Evidence-based Medicine Reviews (Ovid), EMBASE, and Cochrane library databases and were augmented with searches for evidence-based guidelines on radiology and evidence-based medicine Web sites by using the Google Internet search engine. Guidelines were appraised by two independent reviewers by using the Appraisal of Guidelines Research and Evaluation Collaboration Instrument. Other studies were appraised by using structured appraisal checklists. RESULTS: Five guidelines were identified and five empirical studies met inclusion criteria. All guidelines had poor scores on some Appraisal of Guidelines for Research and Evaluation (AGREE) Collaboration criteria; poorer scores tended to occur in relation to objective assessment of rigor of guideline development, editorial independence, and applicability of the guideline to clinical practice. Lack of agreement was observed among guidelines about the need to stop taking metformin after contrast medium is administered, risk of LA in patients with normal renal function before contrast medium injection, recommended method of measuring renal function, and values used to define abnormal function. The evidence that was used as a basis for determining the guidelines for metformin administration, use of contrast medium, and risk of LA consisted of a limited number of observational studies, including case reports, summaries of case reports, and case series (National Health and Medical Research Council of Australia level IV-V evidence). More important, it was not apparent that a systematic search strategy had been used to identify the studies referenced by the guidelines nor that the referenced studies had been appraised. Individual guideline recommendations were not clearly connected to cited references. CONCLUSION: Substantial inconsistencies exist between the recommendations of the five international guidelines about contrast medium administration in patients who are taking metformin. These are, in part, caused by the low level of evidence underpinning guideline recommendations.

Echocardiography as a Screening Test for Myocardial Scarring in Children with Hypertrophic Cardiomyopathy.

Introduction. Hypertrophic cardiomyopathy (HCM) is burdened with morbidity and mortality including tachyarrhythmias and sudden cardiac death. These complications are attributed in part to the formation of proarrhythmic scars in the myocardium. The presence of extensive LGE is a risk factor for adverse outcomes in HCM. Late gadolinium enhancement (LGE) cardiac magnetic resonance imaging (cMRI) is the standard for the noninvasive evaluation of myocardial scars. However, echocardiography represents an attractive screening tool for myocardial scarring. The aim of this study was to compare the suitability of echocardiography to detect myocardial scars to the standard of cMRI-LGE. Methods. The cMRI studies and echocardiograms from 56 consecutive children with HCM were independently evaluated for the presence of cMRI-LGE and echocardiographic evidence of scarring by expert readers. Results. Echocardiography had a high sensitivity (93%) and negative predictive value (94%) in comparison to LGE. The false positive rate was high, leading to a low specificity (37%) and a low positive predictive value (35%). Conclusions. Given the poor specificity and positive predictive value, echocardiography is not a suitable screening test for the presence of myocardial scarring in children with HCM. However, children without echocardiographic evidence of myocardial scarring may not need to undergo cardiac magnetic resonance imaging to "rule in" LGE.

Wisdom from the front lines: clinicians' descriptions of treating agitation in the nursing home, a pilot study.

The management of behavior problems is one of the most difficult challenges a clinician must face when treating patients with dementia. This article presents a qualitative analysis of the responses of 7 nursing home physicians and 1 nurse practitioner to open-ended questions regarding their experiences in treating behavior problems in dementia with an emphasis on nonpharmalogical methods. This study serves to highlight both the issues encountered by those commonly asked to treat behavior problems in the nursing home, and the thoughtfulness and insight developed by some clinicians to address the problems. Several themes emerged from clinicians' responses. Some of the clinicians developed algorithms for treating behavior problems. Some of the clinicians were frustrated with the expectation that behavior problems would be effectively treated pharmacologically. The treatment of behavior problems was described as complex and requiring more time than is allocated by reimbursement systems. They also expressed the need for multiple systemic changes in order to improve treatment, and provided many examples of inadequate resources, including reimbursement, staff, activities, staff training, and management issues needed to improve treatment of behavior problems in nursing home residents. On the positive side, they reported a high level of satisfaction when treating behavior nonpharmacologically. The clinicians felt that with appropriate systemic change many behavior problems can be either prevented or treated effectively by nonpharmacological means.

Bacterial skin and soft tissue infections in older adults.

This article focuses on the clinical manifestations of the more common geriatric skin and soft tissue infections caused by direct invasion of the skin by bacteria. The approach will enable the clinician to create a differential diagnosis to choose the proper empiric therapy. Less common conditions will be mentioned in passing principally as part of a differential. Fungal and viral skin infections are covered in other articles in this edition.