A preliminary study of blood-oxygen-level-dependent MRI in patients with chronic kidney disease.

BACKGROUND: Blood-oxygen-level-dependent (BOLD) magnetic resonance imaging (MRI) can provide regional measurements of oxygen content using deoxyhemoglobin paramagnetic characteristics. The apparent relaxation rate or R2*(=1/T2*) can be determined from the slope of log (intensity) versus echo time and is directly proportional to the tissue content of deoxyhemoglobin. Thus, as the level of deoxyhemoglobin increases, T2* will decrease, leading to an increase in R2*. Chronic kidney disease (CKD) can affect oxygenation levels in renal parenchyma, which influences the clinical course of the disease. The goal of this study was to detect and assess renal oxygenation levels in CKD using BOLD MRI. METHODS: Fifteen healthy subjects and 11 patients with CKD underwent a renal scan using multigradient-recalled-echo sequence with eight echoes. R2* (1/s) of the renal cortex and medulla was measured on BOLD images. Of the 11 patients, nine had biopsy-proven chronic glomerulonephritis, and two had a similar diagnosis based on clinical symptoms and investigations. RESULTS: Mean medullary R2* (MR2*) and cortex R2* (CR2*) levels were significantly higher in patients (22 kidneys, MR2*=24.79±4.84 s(-1), CR2*=18.97±2.72 s(-1)) than in controls (30 kidneys, MR2*=19.98±1.19 s(-1), CR2*=16.03±1.23 s(-1)) (P<.01), and MR2* was increased more than CR2*. Medullary to cortical R2* ratios (MCR2*) of patients were significantly increased when compared with those of controls (P<.01). In the patient group, estimated glomerular filtration rate levels were greater than or equal to 60 ml/min/1.73 m(2) in six patients (12 kidneys), whose MR2* and CR2* were also significantly higher than those of controls (P<.01). Serum creatinine levels were normal in seven patients (14 kidneys), whose MR2*, CR2* and MCR2* were also higher than those of controls (P<.01). CONCLUSIONS: BOLD MRI can be used to evaluate changes in renal oxygenation in CKD, suggesting that it has the potential to be an excellent noninvasive tool for the evaluation of renal function.

Evaluation of cirrhotic liver with perfusion-weighted magnetic resonance imaging: a preliminary experimental study in animal models with half-liver cirrhosis / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the role of perfusion-weighted magnetic resonance imaging (MRI) in evaluation of cirrhotic liver.</p><p><b>METHODS</b>With a 4F catheter, 1% diluted carbon tetrachloride (1 ml/kg) was selectively injected into right or left hepatic artery of 12 dogs fortnightly. The half liver into which carbon tetrachloride was injected was called as study side (SS), while the other half liver without carbon tetrachloride injection was called as study control side (SCS). Conventional and perfusion-weighted MRI were performed in every 4 weeks. Via a 4F catheter, 5ml gadolinium diethylentriamine pentaaceti acid (Gd-DTPA) dilution was injected into superior mesenteric artery at the 5th scan. The signal intensity-time curves of SS, SCS, and portal vein were completed in MR workstation. The maximal relative signal increase (MRSI), peak time (tp), and slope of the curves were measured.</p><p><b>RESULTS</b>On conventional MR images, no abnormalities of externality and signal intensity were observed in both SS and SCS of liver at each stage. The mean tp, MRSI, and slope of intensity-time curves in normal liver were 10.56 seconds, 1.01, and 10.23 arbitrary unit (au)/s, respectively. Three parameters of curves didn't show obvious change in SCS of liver at every stage. Abnormal perfusion curves occurred in SS of liver at the 12th week after the 1st injection. The abnormality of perfusion curve in SS was more and more serious as the times of injection increased. The mean tp, MRSI, and slope intensity-time curves in SS of liver were 19.45 seconds, 0.43, and 3.60 au/s respectively at the 24th week.</p><p><b>CONCLUSION</b>Perfusion-weighted imaging can potentially provide information about portal perfusion of hepatic parenchyma, and to some degree, reflect the severity of cirrhosis.</p>

Assessment of acute mesenteric ischemia with multi-slice spiral CT / 中国医学科学院学报

<p><b>OBJECTIVE</b>To explore the clinical value of multi-slice spiral CT (MSCT) in diagnosis of acute mesenteric ischemia.</p><p><b>METHODS</b>MSCT, including plain scan, the arterial phase scan, and the portal vein phase scan, was performed in 18 patients who were suspected of acute intestinal ischemia. The mesenteric arteries and portal veins were imaged with techniques including volume-rendered technique, multi-planar reconstruction, and maximum intensity projection-thin. All of them were also examined with digital subtractive angiography (DSA). The diagnostic results of MSCT were compared with those of DSA, and the abnormal MSCT findings were analyzed.</p><p><b>RESULTS</b>Bowel wall thickening, mesenteric edema, and ascites were most commonly seen in venous thromboses, while luminal dilatation and air-fluid levels were commonly seen in arterial embolization. Except that pneumatosis was only seen in transmural infarction, all the abnormal CT findings were found in different patterns and different degrees of ischemia.</p><p><b>CONCLUSIONS</b>The integrated MSCT examination is a valuable tool in diagnosis of acute intestinal ischemia. It can accurately diagnose acute intestinal ischemia and is also useful to assess the degrees of ischemia.</p>

Injuries of anterior glenoid labrum:evaluation with MR arthrography / 中华放射学杂志

Objective To determine the diagnostic value of shoulder MR arthrography in revealing the injuries of anterior glenoid labrum,and to compare MR arthrography with arm in neutral position with MR arthrography with arm in abduction and external rotation(ABER)position.Methods MR arthrography of the shoulder,including additional oblique axial sequences with the patient in the ABER position,was performed in 44 patients.The injuries of anterior glenoid labrum of these patients were retrospectively evaluated.The result was compared with that of arthroscopy.Results For displaying the abnormalities of anterior glenoid labrum,the sensitivity,specificity,and accuracy of axial MR images with arm in neutral position were 79.3%(23/29),100%(15/15),and 86.4%(38/44),respectively.While the results of ABER position oblique axial images were 93.1%(27/29),100%(15/15),and 95.5%(42/44), respectively.The difference of sensitivity between axial and ABER-position scans was statistically significant (P