Intravascular ultrasonographic findings in May-Thurner syndrome (iliac vein compression syndrome).

The objective of this series was to describe the findings in 2 types of iliac vein compression syndrome on intravascular ultrasonography. We conducted a retrospective review of the intravascular ultrasonographic findings in 2 patients with iliac vein compression syndrome due to 2 different types of venous spur and correlated those findings with the contrast-enhanced venographic findings. Intravascular ultrasonography allowed differentiation of the 2 different types of iliac vein compression syndrome in analogy to the venographic classification. Both cases had compression of the left common iliac vein between the right common iliac artery and the vertebral bodies. In addition, hyperechogenic eccentric wall thickening, the presence of multiple vascular channels separated by hyperechogenic structures, and the presence of sequelae of deep venous thrombosis such as synechiae and organized thrombus can be seen on intravascular ultrasonography. The ability to perform exact measurements of the venous dimensions is an added benefit of intravascular ultrasonography. Intravascular ultrasonography can assist in the diagnosis and classification of iliac vein compression syndrome, allows assessment of its complications, and can be potentially helpful for planning endovascular treatment.     

Can sensitization to aeroallergens disappear over time in children with allergic disease?

Background: Remittance of aeroallergen sensitization has been shown in population‐based studies, but there is a common perception that sensitization to aeroallergens rarely if ever disappears in children with allergic disease. Methods: We retrospectively reviewed all specific IgE tests carried out in children aged 0–18 years at our hospital laboratory over a 14‐year period. Of 3115 children sensitized to one or more aeroallergens, 244 (7.8%) were retested after a mean (SD) period of 45 (28) months at their physician’s discretion. Results: Disappearance of sensitization to individual aeroallergens did occur, with remittance rates ranging from 3.1% for house dust mite to 17.5% for cat. However, complete remittance of aeroallergen sensitization was found in only one subject. In up to 35% of cases, remittance of sensitization was offset by the appearance of one or more new aeroallergen sensitizations. Remittance was only observed in children sensitized to multiple allergens (with a median of 3 aeroallergen sensitizations), and their median degree of sensitization was low (median 2.1 kU/L). Conclusion: Aeroallergen sensitization can disappear in children with allergic disease, but only in polysensitized individuals. Complete remittance of sensitization to aeroallergens is rare in symptomatic children.     

XTC MRI: sensitivity improvement through parameter optimization.

Xenon polarization Transfer Contrast (XTC) MRI pulse sequences permit the gas exchange of hyperpolarized xenon-129 in the lung to be measured quantitatively. However, the pulse sequence parameter values employed in previously published work were determined empirically without considering the now-known gas exchange rates and the underlying lung physiology. By using a theoretical model for the consumption of magnetization during data acquisition, the noise intensity in the computed gas-phase depolarization maps was minimized as a function of the gas-phase depolarization rate. With such optimization the theoretical model predicted an up to threefold improvement in precision. Experiments in rabbits demonstrated that for typical imaging parameter values the optimized XTC pulse sequence yielded a median noise intensity of only about 3% in the depolarization maps. Consequently, the reliable detection of variations in the average alveolar wall thickness of as little as 300 nm can be expected. This improvement in the precision of the XTC MRI technique should lead to a substantial increase in its sensitivity for detecting pathological changes in lung function.     

Perfusion of the kidney using extraslice spin tagging (EST) magnetic resonance imaging.

This study was undertaken to determine whether extraslice spin tagging (EST) perfusion-weighted magnetic resonance imaging is suitable for screening persons for renal perfusion deficits. Six normal and seven patient volunteers with suspected decreased renal perfusion due to renal vascular disease were imaged. X-ray angiograms were also obtained on all patients. The normalized EST signal intensity showed a linear correlation with respect to the percent stenosis measured from the X-ray angiograms. This demonstrates the potential utility of using EST for the evaluation of kidney perfusion, which was done without the need for exogenous MR contrast agents. EST is fast and less expensive than contrast-based methods. These features make EST a candidate for routine screening of patients for renal vascular disease and for the assessment of angiographically equivocal renal artery stenoses. J. Magn. Reson. Imaging 1999;10:886-891.     

The prevalence and causes of chronic diarrhea in patients with celiac sprue treated with a gluten-free diet

BACKGROUND & AIMS: The majority of patients with celiac sprue experience diarrhea before diagnosis. There have been no studies of the prevalence or causes of chronic diarrhea in these patients after treatment with a gluten-free diet. METHODS: Seventy-eight patients with celiac sprue (59 women and 19 men) treated with a gluten-free diet for at least 12 months were surveyed about their bowel habits. Those with chronic diarrhea, defined as passage of loose stools three or more times per week for 6 months, underwent an extensive diagnostic evaluation to determine its cause. RESULTS: Sixty-two of the 78 patients (79%) experienced diarrhea before treatment, and 13 (17%) had chronic diarrhea (of lesser severity) after treatment. The causes of diarrhea in 11 patients consenting to this study were microscopic colitis, steatorrhea secondary to exocrine pancreatic insufficiency, dietary lactose or fructose malabsorption, anal sphincter dysfunction causing fecal incontinence, and the irritable bowel syndrome. Only 1 patient had antigliadin antibodies detected in serum or small intestinal villous atrophy. CONCLUSIONS: After treatment of celiac sprue with a gluten-free diet, chronic diarrhea persists in a substantial percentage of patients. Although ongoing gluten ingestion is one possible cause, other causes may be more frequent. Therefore, diagnostic investigation of diarrhea in celiac sprue after treatment seems warranted. (Gastroenterology 1997 Jun;112(6):1830-8)