Basic study of susceptibility-weighted imaging at 1.5T

With the aim of sequence optimization in susceptibility-weighted imaging (SWI), 2 image acquisition parameters (slice thickness and matrix size) and 2 image processing conditions (number of slices per minimum intensity projection (MIP) and Sliding Window) were investigated using a 1.5-T magnetic resonance imaging (MRI) system. The subjects were 12 healthy volunteers and the target region for scanning was the whole brain. Informed consent was obtained from all subjects. First, susceptibility-weighted images were acquired with various slice thicknesses from 1mm to 5mm and various matrix sizes from 256 x 256 to 512 x 512, and the images were assessed in terms of the contrast-to-noise ratio (CNR) and were also visually evaluated by three radiologists. Then, the number of slices per MIP and the usefulness of the Sliding Window were investigated. In the study of the optimal slice thickness and matrix size, the results of visual evaluation suggested that a slice thickness of 3mm and a matrix size of 448 x 448 are optimal, while the results of evaluation based on CNR were not significant. As regards the image processing conditions, the results suggested that the number of slices per MIP should be set to a minimum value of 2 and that the use of Sliding Window is effective. The present study provides useful reference data for optimizing SWI sequences.     

Noninvasive evaluation of pulmonary capillary wedge pressure in patients with acute myocardial infarction by deceleration time of pulmonary venous flow velocity in diastole.

OBJECTIVES: This study investigates the correlation between deceleration time of diastolic pulmonary venous flow (PV-DT) and of early filling mitral flow (LV-DT), and pulmonary capillary wedge pressure (PCWP) in patients with acute myocardial infarction (AMI). BACKGROUND: An earlier study suggests that Doppler-derived LV-DT provides an accurate means of estimating PCWP in postinfarction patients with left ventricular systolic dysfunction. Furthermore, recent studies have suggested that PCWP correlates better with PV-DT than with LV-DT. However, the value of PV-DT and LV-DT for assessment of PCWP in patients with AMI has not been evaluated. METHODS: In 141 consecutive patients with AMI, we measured PV-DT and LV-DT by Doppler echocardiography, and compared these variables with PCWP measured using a Swan-Ganz catheter. RESULTS: There was a weak negative correlation between the LV-DT and PCWP (r = -0.54). Although the sensitivity of < or =130 ms in LV-DT in predicting > or =18 mm Hg in PCWP was high (86%), its specificity was low (59%). On the other hand, a very close negative correlation was found between PV-DT and PCWP (r = -0.89). The sensitivity and specificity of < or =160 ms in PV-DT in predicting > or =18 mm Hg in PCWP were 97% and 96%, respectively. CONCLUSIONS: In patients with AMI, Doppler-derived PV-DT showed a stronger correlation with PCWP than LV-DT.     

Learning Curve of Emergency Physicians Using Emergency Bedside Sonography for Symptomatic First‐Trimester Pregnancy

Objective. The purpose of this study was to prospectively assess the learning curve of emergency physician training in emergency bedside sonography (EBS) for first‐trimester pregnancy complications. Methods. This was a prospective study at an urban academic emergency department from August 1999 through July 2006. Patients with first‐trimester vaginal bleeding or pain underwent EBS followed by pelvic sonography (PS) by the Department of Radiology. Results of EBS were compared with those of PS using a predesigned standardized data sheet. Results. A total of 670 patients underwent EBS for first‐trimester pregnancy complications by 1 of 25 physicians who would go on to perform at least 25 examinations. The sensitivity and specificity of EBS for an intrauterine pregnancy increased from 80% (95% confidence interval [CI], 71%–87%) and 86% (95% CI, 76%–93%), respectively, for a physician's first 10 examinations to 100% (95% CI, 73%–100%) and 100% (95% CI, 63%–100%) for those performed after 40 examinations. Likewise, the sensitivity and specificity for an adnexal mass or ectopic pregnancy changed from 43% (95% CI, 28%–64%) and 94% (95% CI, 89%–97%) to 75% (95% CI, 22%–99%) and 89% (95% CI, 65%–98%), whereas the sensitivity and specificity for a molar pregnancy changed from 71% (95% CI, 30%–95%) and 98% (95% CI, 94%–99%) to 100% (95% CI, 20%–100%) and 100% (95% CI, 81%–100%). Although detection of an intrauterine or a molar pregnancy improved with training, even with experience including 40 examinations, the sensitivity of EBS for an adnexal mass or ectopic pregnancy was less than 90%. Conclusions. There is an appreciable learning curve among physicians learning to perform EBS for first‐trimester pregnancy complications that persists past 40 examinations.     

Japanese encephalitis in the Kurume region of Japan: CT and MRI findings

Summary Neurological, computed tomography (CT) and magnetic resonance imaging (MRI) findings were recorded from 13 patients with Japanese encephalitis (JE) in the Kurume region diagnosed by serological criteria. The patients averaged 63 years of age, and 5 were older than 70 years. The serological data mostly indicated a primary response. Hemiplegia and tetraplegia were common, together with extrapyramidal signs. A few cases had a stroke-like onset and cerebral haemorrhage during the course of JE. CT and MRI in 7 cases revealed abnormalities in the thalamus and basal ganglia including the putamen. The CT and MRI findings from the acute stage to the convalescent stage were considered to be characteristic of JE.     

A case of pulmonary leiomyoma

We report a case of pulmonary parenchymal leiomyoma. The patient was a 35- year-old female with a tumor in anterobasal segment of the left lung. Enucleation was performed. The tumor was ball type and 2 cm in diameter, showing smooth and reddish brown cut surface. Microscopic and electron microscopic histology proved it to be leiomyoma.     

Normal female urethra and paraurethral structure--evaluation with MR imaging

The appearance of the normal female urethra on magnetic resonance (MR) images was studied in 40 patients by means of a 1.5 Tesla unit. Morphologic characteristics and anatomic details of the urethra and pubourethral ligament were demonstrated in each patient. MR imaging depicted an outer muscle layer of low signal intensity. Medial to the outer muscle layer, the submucosa was seen as a high-signal-intensity ring, followed by an inner low-signal-intensity ring. In the mid-urethra, a central high-signal-intensity spot was seen in 38% of cases, a finding that may be related to urine and mucus within the mucosal cells. The zonal anatomy of the female urethra was obscure in the over 60 years of age. MR imaging is an excellent tool for demonstrating female urethral anatomy.     

Case of primary aorto-jejunal fistula caused by gram-positive cocci

A 46 year-old man was transferred to our department with a pulsating abdominal mass and back pain. On arrival he suddenly developed hematemesis. CT suggested the presence of an infrarenal aortic aneurysm and the jejunum was filled with contrast medium. An emergency operation was done. We found an aorto-jejunal fistula at the branching point of the renal artery. We directly sutured the aortic wall laceration and the jejunum wall in two layers. Then we resected infrarenal pseudoaneurysm as completely as possible, with replacement by a Dacron Y-shaped prosthesis. Culture of the aortic wall showed gram-positive cocci, but the species could not be identified. Gram stain of the aortic wall also showed infection by gram-positive cocci. The patient is alive and well 3 months after surgery.