Heather N. Burbank

Syndromes of the First and Second Branchial Arches, Part 2: Syndromes

SUMMARY: A variety of congenital syndromes affecting the face occur due to defects involving the first and second BAs. Radiographic evaluation of craniofacial deformities is necessary to define aberrant anatomy, plan surgical procedures, and evaluate the effects of craniofacial growth and surgical reconstructions. High-resolution CT has proved vital in determining the nature and extent of these syndromes. The radiologic evaluation of syndromes of the first and second BA should begin first by studying a series of isolated defects (cleft lip with or without CP, micrognathia, and EAC atresia) that compose the major features of these syndromes and allow a more specific diagnosis. After discussion of these defects and the associated embryology, we discuss PRS, HFM, ACS, TCS, Stickler syndrome, and VCFS.

Linear Longitudinal Decline in Fractional Anisotropy in Patients with Amyotrophic Lateral Sclerosis

Background and Purpose:As potential therapies aimed at halting or slowing the decline in upper motor neuron function in patients with amyotrophic lateral sclerosis (ALS) or primary lateral sclerosis (PLS) are developed, a quantitative method for monitoring response will be necessary. Measurement of fractional anisotropy (FA) using diffusion tensor imaging (DTI) over time should parallel functional decline from upper motor neuron degeneration in these patients.Patients and Methods:Two patients with definite ALS were imaged at 3.0 T and FA values were obtained in the corticospinal tract every 3 months for 1 year. The FA values were compared to normal age-matched controls.Results:Both patients showed linear decreases in FA values over time with R2 values ranging from 0.93 to 0.99. The decline became statistically significant over the course of the study. Qualitative decreases in anisotropy were also evident on FA maps.Conclusion:If these trends can be validated in greater numbers of patients, DTI may serve as an objective quantitative biomarker for disease progression in patients with upper motor neuron disease.ZusammenfassungHintergrund und Ziel:Da potentielle Therapien entwickelt werden, welche auch auf die Beendigung oder Verlangsamung der Funktionsminderung der oberen Motoneuronen bei Patienten mit amyotrophischer Lateralsklerose (ALS) oder primärer Lateralsklerose (PLS) abzielen, ist eine quantitative Methode zur Reaktionskontrolle erforderlich. Die Messung der fraktionalen Anisotropie (FA) mittels Diffusions-Tensor-Bildgebung (DTI) im Zeitablauf bei diesen Patienten sollte dem funktionalen Rückgang der Degeneration der oberen Motoneuronen entsprechen.Patienten und Methodik:Zwei Patienten mit nachgewiesener ALS wurden einer Bildgebung mit 3,0 T unterzogen, und 1 Jahr lang wurden alle 3 Monate die FA-Werte im Tractus corticospinalis gemessen. Die FA-Werte wurden mit gesunden, altersentsprechenden Kontrollpersonen verglichen.Ergebnisse:Mit R2-Werten im Bereich von 0,93–0,99 wiesen beide Patienten im Zeitablauf eine lineare Abnahme der FA-Werte auf. Im Verlauf der Studie wurde die Abnahme statistisch signifikant. In den FA-Maps zeigten sich zudem qualitative Rückgänge der Anisotropie.Schlussfolgerung:Wenn sich diese Tendenzen bei einer größeren Anzahl von Patienten nachweisen lassen, kann die DTI bei Patienten mit oberer Motoneuronerkrankung als objektiver quantitativer Biomarker für den Krankheitsfortschritt dienen.

Diffusion tensor imaging and tractography of Rasmussen encephalitis

A 5-year-old girl presented with intractable seizures and nonfocal hemispheric slowing on EEG. Blood, urine, and CSF laboratory values were all normal. MR imaging of the brain demonstrated diffuse volume loss of the entire left hemisphere. Clinical and imaging findings were consistent with the diagnosis of Rasmussen encephalitis. Diffusion tensor imaging demonstrated increased ADC values and decreased fractional anisotropy (FA) of the affected (left) hemisphere. Tractography data showed decreased numbers of lines drawn in the affected hemisphere, with fewer lines drawn at higher FA thresholds, relative to the contralateral hemisphere, or to normal age-matched controls. Diffusion tensor imaging offers an adjunct MR imaging modality in diagnosis and monitoring of this rare condition.

The misinterpretation rates of radiology residents on emergent neuroradiology magnetic resonance (MR) angiogram studies: correlation with level of residency training

The purpose of this study was to determine the discrepancy rates of radiology residents interpreting emergent neck and Circle of Willis magnetic resonance angiography (MRA) studies and to detect any adverse clinical outcomes. Three hundred seventeen MRA studies given preliminary reading by radiology residents were retrospectively reviewed over a 2-year period. Discrepancies were classified as either false negatives (failure to diagnose abnormalities) or false positives (misinterpreting normal scans as abnormal). The overall discrepancy rate was 12.1% for Circle of Willis MRA and 7.9% for neck MRA. Fourth-year residents had the lowest discrepancy rates (7.7%), but this was not statistically significant. The most common misses were stenosis greater than 70% (n = 9) and aneurysm (n = 12). No adverse clinical outcome was detected mainly due to rapid turnaround time for final reporting.

Quality of extracranial carotid evaluation with 256-section CT

BACKGROUND AND PURPOSE: To date, no systematic evaluation of image quality has been performed on the 256-section multidetector CT scanner for extracranial carotid evaluations. We evaluated image quality, patient dose, and examination time and compared these parameters with a 64-section multidetector CT. MATERIALS AND METHODS: We reviewed extracranial CTA scans obtained on a 256-detector CT scanner in 50 consecutive patients. Image quality was analyzed for artifacts and vessel contrast opacification from the aortic arch to the skull base, dose to patient, and scan time. Results were compared with a control group of 50 patients imaged on a 64-section CT scanner. A Fisher exact test was used to analyze both groups with respect to vessel contrast opacification and presence of artifacts, and a Student t test was used to assess differences in patient dose between the 2 groups. RESULTS: Quantitative and qualitative evaluations revealed >95% acceptable vessel opacification at all levels measured on the 256-section scanner. Scan time was improved (4 seconds on 256-channel). There were fewer artifacts related to metallic streak on the 256-channel CTA study, and DLP was lower on the 256-channel CTA (113.9 versus 159.8 mGy). CONCLUSIONS: The 256-channel CTA imaging protocol for carotid arteries yielded similar vessel contrast opacification compared with the 64-channel CTA but with fewer metallic artifacts, a modest decrease in scan time, similar image quality, and a statistically significant reduction in radiation dose of 10%.

Improvements in Lumbar Spine MRI at 3 T Using Parallel Transmission

OBJECTIVE Parallel transmission MRI at 3 T improves image quality by reducing dielectric effects with radiofrequency shimming. The purpose of this study was to determine whether parallel transmission MRI improves signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in lumbar spine MRI at 3 T. MATERIALS AND METHODS Ten healthy volunteers underwent T1-weighted MRI and nine healthy volunteers underwent T2-weighted MRI of the lumbar spine. Sagittal and axial T1- and T2-weighted images were acquired using parallel transmission MRI and conventional MRI. The percentage improvements in SNR and CNR were calculated, and statistical significance was determined using a two-tailed Student t test with p < 0.05 for significance. RESULTS The CNR and SNR showed statistically significant improvements at all levels of the lumbar spine except SNR at T11 on axial T2-weighted imaging. For sagittal T1-weighted imaging, the average improvement with parallel transmission MRI was 53% in CNR and 19% in SNR. For axial T1-weighted imaging, the average improvement was 48% in CNR and 23% in SNR. For sagittal T2-weighted imaging, the average CNR improvement was 38% and the average SNR improvement, 20%. For axial T2-weighted scans, the average percentage improvement in CNR was greater than 100% and the average SNR improvement was 18% with parallel transmission MRI. CONCLUSION The parallel transmission sequence improves image quality of lumbar spine MRI at 3 T, which is quantitatively supported by statistically significant improvements in SNR and CNR.

Obstructive sleep apnea in familial partial lipodystrophy type 2 with atypical skin findings and vascular disease

IntroductionA number of metabolic conditions have been associated with Obstructive Sleep Apnea Syndrome (OSAS). Familial partial lipodystrophy type 2 (FPLD2), one of the few rare genetic disorders affecting total body fat redistribution, is one of those conditions.Case reportIn this case report the authors detail OSAS associated with FPLD2 with atypical dermatological and systemic manifestations.