Acute Abdominal Pain: Is There a Potential Role for MRI in the Setting of the Emergency Department in a Patient with Renal Calculi?
Emory University School of Medicine, Department of Radiology, Atlanta, Georgia 30322, USA. Journal of Magnetic Resonance Imaging
(Impact Factor: 3.21).
11/2010; 32(5):1012-23. DOI: 10.1002/jmri.22337
Acute flank pain is a frequent clinical presentation encountered in emergency departments, and a work-up for obstructive urolithiasis in this setting is a common indication for computed tomography (CT). However, imaging alternatives to CT for the evaluation of renal colic are warranted in some clinical situations, such as younger patients, pregnancy, patients that have undergone multiple prior CT exams and also patients with vague clinical presentations. MRI, although relatively insensitive for the direct detection of urinary calculi, has the ability to detect the secondary effects of obstructive urolithiasis. Using rapid, single shot T2-weighted sequences without and with fat saturation provides an abdominopelvic MR examination that can detect the sequelae of clinically active stone disease, in addition to alternate inflammatory processes that may mimic the symptoms of renal colic. In addition, MR nephro-urography (MRNU) has the ability to provide quantitative analysis of renal function that has the potential to direct clinical management in the setting of obstructing calculi. This review describes the potential utility and limitations of MRI in the emergency setting for diagnosing causes of flank pain and renal colic, particularly in patients with unusual presentations or when an alternative to CT may be warranted.
Figures in this publication
Available from: Mickaël Ohana
- "The inability of T2-W MRU to fully visualize complete nondilated ureters is cited as a major negative point in many papers    . Finally, T2w-MRU has been shown to be a rapid and non-invasive imaging technique which is useful and reliable to reveal hydronephrosis and perirenal high-intensity signals in acute urinary obstruction    . "
[Show abstract] [Hide abstract]
ABSTRACT: Objective: The goal of this prospective study was to compare the efficiency of two types of MRU after diuretic administration to identify the non-dilated ureter. Methods: MR pelvic examinations were performed in 126 patients after receiving furosemide. Each patient underwent in addition to their protocol for context, two types of MRU: 2D T2-weighted FSE (T2w-MRU) and 3D Gd T1-weighted GE (CE-MRU). Four segments were checked for each ureter. For the first part of the analysis, readers evaluated the whole image quality using a four points subjective scale and for the second part, they were asked to score separately each ureteral segment as present or absent. Results: 1008 ureteral segments were checked. For the image quality, readers did not find any significant difference (3.8 ± 0.5 vs 3.6 ± 0.7, p value: 0.13) between MRU methods. The interobserver agreement was excellent with a K correlation coefficient as high as 0.89 for T2w-MRU and 0.92 for CE-MRU, respectively. For the detection of the segments and considering the 9 rotations for the T2W MRU, there were no statistically significant differences between the two groups. Conclusion: T2-weighted MRU with multiple orientations and diuretic is sufficient to identify the non-dilated ureter. It offers information on ureteral peristaltism. It can be suggested that this sequence is able to detect an initial obstruction before hydronephrosis occurs.
12/2014; 1(1). DOI:10.1016/j.ejro.2014.08.001
Available from: ajronline.org
[Show abstract] [Hide abstract]
ABSTRACT: The purpose of this study was to focus attention on the technique factors commonly used in survey CT scans (e.g., scout, topogram, or pilot scans) to measure the radiation exposure from typical survey CT scans, to compare their exposure to that of typical chest radiographs, and to explore methods for radiation exposure reduction.
The default survey CT scans on 21 CT scanners, representing three different vendors and 11 different models, were investigated. Exposure measurements were obtained with an ion chamber at isocenter and adjusted to be consistent with standard chest radiographic exposure measurement methods (single posterior-anterior projection). These entrance exposures were compared with those of typical chest radiographs, for which the mean for average-sized adults is 16 mR (4.1 x 10(-6) C/kg).
The entrance exposures of the default survey CT scans ranged from 3.2 to 74.7 mR (0.8 to 19.3 x 10(-6) C/kg), which is equivalent to approximately 0.2 to 4.7 chest radiographs. By changing the default scan parameters from 120 kVp to 80 kVp and the tube position from 0 degrees (tube above table) to 180 degrees (tube below table), the entrance exposure for the survey CT scan was reduced to less than that of one chest radiograph for all CT scanners.
For institutions at which the interpreting radiologists do not rely heavily on the appearance of the survey CT image, we recommend adjusting the technique parameters (kilovoltage and X-ray tube position) to decrease radiation exposure, especially for vulnerable patient populations such as children and young women.
American Journal of Roentgenology 09/2005; 185(2):509-15. DOI:10.2214/ajr.185.2.01850509 · 2.73 Impact Factor
Available from: 22.214.171.124
[Show abstract] [Hide abstract]
ABSTRACT: OBJECTIVE: In this article, we review the standard of care for imaging of nephrolithiasis as well as new technology and radiation concerns from the perspective of the urologic surgeon. CONCLUSION: Nephrolithiasis is a common cause of morbidity with a lifetime prevalence of 5-10% worldwide. Increasingly, diagnostic evaluation and planning for medical or surgical intervention have become reliant on imaging.
American Journal of Roentgenology 06/2011; 196(6):1274-8. DOI:10.2214/AJR.11.6434 · 2.73 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.