Scintigraphic evaluation of myocardial uptake of thallium 201 and technetium 99m pyrophosphate utilizing a rat model of chronic doxorubicin cardiotoxicity

To evaluate the usefulness of myocardial scintigraphy as a monitoring tool for chronic doxorubicin (DXR) cardiotoxicity, a rat model was used to investigate the relationship between the myocardial uptake of thallium 201 (Tl) or rechnetium 99m pyrophosphate (^99mTc-PPi) and histological changes of the heart. Although there was no significant difference in myocardial Tl uptake between control and DXR-treated rats at an early phase after Tl injection, late-phase Tl uptake was significantly higher in the DXR-treated rats than in the control rats, indicating a slow wash-out of Tl from the myocardium. The wash-out rate calculated from scintigraphic examination of DXR-treated rats was significantly decreased with increasing degree of cardiomyopathy. Since the Tl wash-out rate was sharply decreased even in animals with minimal histological changes, it may be a possible monitoring tool for the early detection of chronic DXR cardiotoxicity. On the other hand, myocardial^99mTc-PPi images could be obtained only in rats with severe myocardial changes and hence would not useful for early detection.     

NASOGALLBLADDER DRAINAGE FOR MIRIZZI’S SYNDROME

The authors experienced a case of Mirizzi’s syndrome successfully treated with endoscopic nasogallbladder drainage (ENGBD). The patient was a 63‐year‐old man. He was admitted with abdominal pain and jaundice. Laboratory data indicated leukocytosis and elevation of serum bilirubin level. Abdominal ultrasound showed marked swelling of gallbladder and debris in the gallbladder, therefore, the authors strongly suspected Mirizzi’s syndrome. He had past history of acute myocardial infarction and treated with anticoagulation therapy. Then, the authors couldn’t perform surgical removal or percutaneous transhepatic drainage, and tried endoscopic transpapillary drainage. Endoscopic retrograde cholangiopancreatography revealed smooth stricture in the superior portion of common bile duct and occlusion of the cystic duct, and ENGBD was then performed. After ENGBD, his complaints, laboratory data, swelling of gallbladder and stricture of common bile duct were all remarkably improved.     

The current role of preoperative and intraoperative autologous blood donation in pediatric open-heart surgery

Objective: We assessed the current role of preoperative and intraoperative autologous blood donation in pediatric open-heart surgery. Methods: Group 1 consisted of 51 patients between 5 and 10 years old who underwent preoperative autologous blood donation. Group 2 consisted of 50 age-matched patients without preoperative donation as controls. Intraoperative donation was conducted in both groups prior to cardiopulmonary bypass. We evaluated perioperative blood cell count, blood loss, and the need for homologous blood products. Results: No serious complications occurred in preoperative or intraoperative donation. Total preoperative donation storage was 17.5±3.4 mL/kg. Intraoperative donation was 21.7 ±6.1 mL/kg in Group 1 and 12.8±4.0 mL/kg in Group 2 (p<0.001). On admission, serum hemoglobin was lower in Group 1 (12.2±1.0 g/dL versus 13.6±1.6 g/dL, p<0.001) but returned postoperatively to the preoperative value. It hovered at a depressed level in Group 2 (12.2±1.4 versus 10.2±1.1 g/dL, p<0.001). The homologous blood requirement was significantly less in Group 1 than in Group 2 (0% versus 10%, p<0.05). Postoperative platelet counts showed similar curves, and blood loss was not statistically significantly different between groups. Conclusion: Preoperative and intraoperative donations are safe and continue to contribute uniquely to blood conservation, providing important options in comprehensive blood conservation programs in current pediatric open-heart surgery.     

N10 potential as an antidromic motor evoked potential in a median nerve short-latency somatosensory evoked potential study.

When stimulating the mixed nerve to record evoked potential, both sensory and motor fibers are activated before entering the spinal cord. The N10 potential has been described as an antidromic motor evoked potential based on results obtained by recording at the anterior midneck. In the present study, we examined the changes in latencies of Erb's potential, N10, and N13 by stimulating the median nerve distally at the wrist and proximally at the elbow. The conduction velocity of N10 calculated by the difference between N10 latencies at the two stimulation points was consistent with motor conduction velocity, although N13 conduction velocity estimated by the same method reflected a sensory conduction velocity. A positive relation was also observed between the indirect latency from the stimulation point to the anterior root as calculated using the equation (F - M - 1) / 2 (ms) and the direct latency to the negative peak of the N10 potential. Our data support the notion that N10 represents antidromic motor potential originating in the spinal entry zone of the anterior root.     

Dynamic gadolinium-enhanced echo-planar MR imaging of the liver: Effect of pulse sequence and dose on enhancement

To develop guidelines for clinical magnetic resonance imaging of the liver, the authors undertook an animal study to investigate the effect of dose and pulse sequence on liver signal intensity in gadopentetate dimeglumine—enhanced echo-planar imaging. Serial imaging of the liver was performed in anesthetized rats after intravenous administration of five different doses (0.01, 0.05, 0.1, 0.2, and 0.5 mmol/kg) of contrast agent, with six different pulse sequences. The results show that gadopentetate dimeglumine—enhanced echo-planar images obtained during the perfusion phase can yield either positive (due to increased T1 relaxation rates) or negative (due to susceptibility-induced increased T2 relaxation rates) liver enhancement depending on choice of pulse sequence and dose. At the current clinically recommended dose of 0.1 mmol/kg, maximal liver signal enhancement was seen with a T1-weighted inversion-recovery sequence, while maximal liver signal diminution was seen with a T2*-weighted gradient-echo sequence. The authors conclude that gadopentetate dimeglumine—enhanced echo-planar imaging can provide T1, T2, and T2* contrast that may be exploited for both lesion detection and lesion characterization.