Upper airway volume segmentation analysis using cine MRI findings in children with tracheostomy tubes.

OBJECTIVE: The purpose of this study is to evaluate the airway dynamics of the upper airway as depicted on cine MRI in children with tracheotomy tubes during two states of airflow through the upper airway. MATERIALS AND METHODS: Sagittal fast gradient echo cine MR images of the supra-glottic airway were obtained with a 1.5T MRI scanner on seven children with tracheotomy tubes. Two sets of images were obtained with either the tubes capped or uncapped. The findings of the cine MRI were retrospectively reviewed. Volume segmentation of the cine images to compare the airway volume change over time (mean volume, standard deviation, normalized range, and coefficient of variance) was performed for the capped and uncapped tubes in both the nasopharynx and hypopharynx (Signed Rank Test). RESULTS: Graphical representation of the airway volume over time demonstrates a qualitative increased fluctuation in patients with the tracheotomy tube capped as compared to uncapped in both the nasopharyngeal and hypopharyngeal regions of interest. In the nasopharynx, the mean airway volume (capped 2.72 mL, uncapped 2.09 mL, p = 0.0313), the airway volume standard deviation (capped 0.42 mL, uncapped 0.20 mL, p = 0.0156), and the airway volume range (capped 2.10 mL, uncapped 1.09 mL, p = 0.0156) were significantly larger in the capped group of patients. In the hypopharynx, the airway volume standard deviation (capped 1.54 mL, uncapped 0.67 mL, p = 0.0156), and the airway volume range (capped 6.44 mL, uncapped 2.93 mL, p = 0.0156) were significantly larger in the capped tubes. The coefficient of variance (capped 0.37, uncapped 0.26, p = 0.0469) and the normalized range (capped 1.52, uncapped 1.09, p = 0.0313) were significantly larger in the capped tubes. CONCLUSION: There is a statistically significant change in airway dynamics in children with tracheotomy tubes when breathing via the airway as compared to breathing via the tracheotomy tube.

Comparison of lingual tonsil size as depicted on MR imaging between children with obstructive sleep apnea despite previous tonsillectomy and adenoidectomy and normal controls.

BACKGROUND: Cine MRI has become a useful tool in the evaluation of patients with persistent obstructive sleep apnea (OSA) despite previous surgical intervention and in patients with underlying conditions that render them susceptible to multilevel airway obstruction. Findings on cine MRI studies have also increased our understanding of the mechanisms and anatomic causes of OSA in children. OBJECTIVE: To compare lingual tonsil size between children with OSA and a group of normal controls. In addition, a subanalysis was made of the group of children with OSA comparing lingual tonsils between children with and without underlying Down syndrome. MATERIALS AND METHODS: Children with persistent OSA despite previous palatine tonsillectomy and adenoidectomy and controls without OSA underwent MR imaging with sagittal fast spin echo inversion-recovery images, and lingual tonsils were categorized as nonperceptible at imaging or present and measurable. When present, lingual tonsils were measured in the maximum anterior-posterior diameter. If lingual tonsils were greater than 10 mm in diameter and abutting both the posterior border of the tongue and the posterior pharyngeal wall, they were considered markedly enlarged. RESULTS: There were statistically significant differences between the OSA and control groups for the presence vs. nonvisualization of lingual tonsils (OSA 33% vs. control 0%, P=0.0001) and mean diameter of the lingual tonsils (OSA 9.50 mm vs. control 0.0 mm, P=0.00001). Within the OSA group, there were statistically significant differences between children with and without Down syndrome for the three lingual tonsil width categories (P=0.0070) and occurrence of markedly enlarged lingual tonsils (with Down syndrome 35% vs. without Down syndrome 3%, P=0.0035). CONCLUSIONS: Enlargement of the lingual tonsils is relatively common in children with persistent obstructive sleep apnea after palatine tonsillectomy and adenoidectomy. This is particularly true in patients with Down syndrome.

Three-dimensional rotational angiography of neurovascular lesions in pediatric patients.

OBJECTIVE: In this pictorial essay, we review the 3D rotational angiography (RA) studies of six pediatric patients; in these cases, the information obtained with 3D RA was uniquely beneficial in diagnosis and treatment planning. CONCLUSION: Three-dimensional RA is an excellent tool for the evaluation of a number of intracranial lesions in pediatric patients: There is less total radiation exposure from a single rotational run than from CT or a conventional angiography examination that involves more than one view and the study is quick, with data acquisition requiring less than 8 sec and fully rendered 3D reconstructions generated within 180 sec.

Skimboarder's toe: findings on high-field MRI.

OBJECTIVE: Our purpose is to report hyperdorsiflexion injuries of the metatarsophalangeal joints associated with the sport of skimboarding and to describe the MRI appearance of these injuries. CONCLUSION: Skimboarding can be associated with hyperdorsiflexion injuries of the metatarsophalangeal joint. MRI shows that such injuries are associated with hyperdorsiflexion of the extensor hallucis longus or extensor digitorum longus tendon, causing tear of the extensor expansion. Unlike turf toe, in which the plantar plate is involved, skimboarder's toe involves structures dorsal to the metatarsophalangeal joint.

Placement of peripherally inserted central catheters without fluoroscopy in children: initial catheter tip position.

PURPOSE: To determine how often placement of peripherally inserted central catheters (PICCs) without imaging guidance results in an initially correct central venous catheter tip location. MATERIALS AND METHODS: This study was approved by the hospital's institutional review board, which waived the requirement for informed consent. In a children's hospital, 843 PICCs were placed in 698 patients (age range, 0 days to 26 years; mean, 6.9 years) during a 14-month study period. All PICCs were placed by a specialized team of PICC nurses and interventional radiology technologists in an angiography suite with the supervision of pediatric interventional radiologists. All catheters were threaded blindly to a previously estimated length by either a PICC nurse or a pediatric interventional radiologist, according to National Association of Vascular Access Networks guidelines, and the initial PICC tip location was then determined by means of spot fluoroscopy. PICC tips were regarded as central if they resided anywhere within the superior vena cava (SVC). All catheters were then manipulated with intermittent fluoroscopic guidance to achieve a final central position in the distal third of the SVC. A chi2 test was used to compare initial and final PICC tip locations according to patient age, catheter size, accessed vein, and need for radiologist assistance. A t test was used to compare procedure time with and without radiologist assistance. RESULTS: Analysis included 843 consecutively placed pediatric PICCs, of which 723 (85.8%) had a noncentral initial PICC tip position and required additional manipulation. After catheter repositioning performed with intermittent fluoroscopic guidance, a final central PICC tip location was achieved in 760 PICCs (90.2%). CONCLUSION: Pediatric PICC placement without fluoroscopic guidance required catheter manipulation of initial PICC tip position in 723 cases (85.8%). PICC placement with fluoroscopic guidance is highly successful, and the authors believe it is best performed in an angiography suite.

Frequency and imaging appearance of hepatic angiomyolipomas in pediatric and adult patients with tuberous sclerosis.

OBJECTIVE: This study evaluates the frequency and imaging appearance of hepatic angiomyolipomas in pediatric and adult patients with tuberous sclerosis. CONCLUSION: Multiple hepatic angiomyolipomas are often found in patients with tuberous sclerosis, particularly in those with bilateral diffuse renal angiomyolipomas.

In-plane bismuth breast shields for pediatric CT: effects on radiation dose and image quality using experimental and clinical data.

OBJECTIVE: The purpose of our study was to evaluate the amount of radiation dose reduction and its effect on image quality when using an in-plane bismuth breast shield for multidetector CT (MDCT) of the chest and abdomen in female pediatric patients. SUBJECTS AND METHODS: Fifty consecutive MDCT examinations (chest, 29; abdomen, 21) of female pediatric patients (mean age, 9 years; range, 2 months-18 years) were performed with a 2-ply (1.7 g of bismuth per square centimeter) bismuth shield (three sizes to accommodate patients of varying sizes) overlying the patient's breasts. MDCT images were evaluated for a perceptible difference in image quality in the lungs at the anatomic level under the shield as compared with nonshielded lung and whether the images were of diagnostic quality. In addition, 2-mm regions of interest were placed in the peripheral anterior and posterior portions of each lung in shielded and nonshielded areas, and noise (standard deviation in Hounsfield units) was measured in the regions. Differences among the regions in noise were compared for shielded versus nonshielded areas (paired t test). To measure differences in actual dose, we also evaluated the breast shield with an infant anthropomorphic phantom using thermoluminescent detectors in the breast tissue. The phantom was imaged with and without the breast shield using identical MDCT parameters. RESULTS: All MDCT scans of patients were of diagnostic quality with no perceptible difference in image quality in shielded versus nonshielded lung. We found no statistically significant difference in noise between the shielded and nonshielded lung regions of interest (shielded: mean noise, 17.3 H; nonshielded: mean noise, 18.8 H; p = 0.5180). Phantom measurements revealed a 29% reduction in radiation dose to the breast when a medium-dose MDCT protocol was used. CONCLUSION: Bismuth in-plane breast shielding for pediatric MDCT decreased radiation dose to the breast without qualitative or quantitative changes in image quality.

Is administration of enteric contrast material safe before abdominal CT in children who require sedation? Experience with chloral hydrate and pentobarbital.

OBJECTIVE: It has been common practice to administer enteric contrast material in preparation for abdominal CT in children who require sedation to be examined. At some institutions, the practice of administering an anesthetic or enteric contrast material before sedation is being challenged because it violates the "nothing by mouth" status that is otherwise strictly enforced before sedation. Our purpose was to review our safety record in administering enteric contrast material for CT before sedation. MATERIALS AND METHODS: Radiology reports, medical records, and department incident reports were reviewed for the past 5 years from all patients who required sedation for abdominal CT. Patient age and sex, type of sedation, and complications (defined as vomiting with aspiration) related to enteric contrast material before the sedation were recorded. For routine oral contrast material, diluted Hypaque (meglumine diatrizoate) was administered in an age-based amount 1-2 hr before scanning. For sedation, depending on the patient's age, either oral chloral hydrate (70-100 mg/kg) or IV pentobarbital (3 mg/kg with repeated doses of up to 7 mg/kg) was used. RESULTS: Three hundred sixty-seven patients who received oral contrast material before sedation for abdominal CT were identified (200 boys, 167 girls; age range, 1 month-19 years; mean age, 2.9 years). Chloral hydrate was used in 30 patients and IV pentobarbital in 337 patients. No complications related to the administration of oral contrast material before sedation were identified. CONCLUSION: The practice of administering oral contrast material in children before sedation for abdominal CT appears to be safe when using the sedation drugs and protocols in place at our institution. Further study of the safety of this practice should be undertaken.

Imaging findings in pediatric patients with persistent airway symptoms after surgery for double aortic arch.

OBJECTIVE: The purpose of this study was to review the imaging findings of children referred for cross-sectional imaging to evaluate persistent airway symptoms after surgical therapy for double aortic arch. CONCLUSION: Airway narrowing is clearly shown on cross-sectional imaging in patients with persistent airway symptoms after surgical therapy for double aortic arch. Two patterns of airway compression are typically seen: narrowing of the trachea at the level of the postsurgical arch and narrowing of the left main bronchus as a result of compression from a midline descending aorta. Both patterns may be seen in patients regardless of whether the left or the right arch has been ligated.

Aberrant subclavian arteries: cross-sectional imaging findings in infants and children referred for evaluation of extrinsic airway compression.

OBJECTIVE: The purpose of our study was to describe patterns of airway compression identified on cross-sectional imaging in infants and children with either right aortic arch and aberrant left subclavian artery or left aortic arch with aberrant right subclavian artery. MATERIALS AND METHODS: Data from MR imaging and CT performed to evaluate pediatric patients for extrinsic airway compression were reviewed for cases that revealed an aberrant right or left subclavian artery. Clinical, endoscopic, and imaging findings in identified cases were reviewed. Recurrent patterns of extrinsic compression were reviewed among cases. RESULTS: Twelve patients with right aortic arch with aberrant left subclavian artery and nine patients with left aortic arch and aberrant right subclavian artery were identified. All 12 with right aortic arch with aberrant left subclavian artery had airway compression shown, with multiple sites or diffuse compression in six. Of these 12 patients, nine had compression at the level of the arch and aberrant subclavian artery (10 had Kommerell's diverticulum), and nine had compression of the distal airway in association with a midline descending aorta. Five of the nine patients with left aortic arch and aberrant right subclavian artery had airway compression shown, all at the level of the arch and aberrant subclavian artery. None of these compressions was associated with either Kommerell's diverticulum or midline descending aorta. CONCLUSION: Both right and left aberrant subclavian arteries can be associated with symptomatic airway compression, but the patterns of compression are different. The airway compression in right aortic arch with aberrant left subclavian artery is often associated with either Kommerell's diverticulum or midline descending aorta, whereas compression associated with left aortic arch and aberrant right subclavian artery is not.