In vivo real-time microangiography of the liver in mice using synchrotron radiation

BACKGROUND/AIMS: The aim of this study was to visualize hepatic microvessels (less than 100 microm in diameter) in vivo, which could not be visualized by conventional X-ray angiography, by using synchrotron radiation (ultra-bright and monochromatic X-ray). METHODS: Five female Balb/c nu/nu mice were used. To investigate the hepatic microvessels under nearly physiologic conditions, we performed in vivo aortography under anesthesia with 370 mgI/ml nonionic iodine contrast medium using monochromatic 17-keV X-rays generated by a synchrotron. Images were captured with a pixel matrix size of 1024 x 1024 at a rate of 30 pictures/s. The field of view was 7 mm x 7 mm and thus the pixel size was approximately 7 microm. Captured images were evaluated both qualitatively and quantitatively. RESULTS: Small hepatic arterial and portal venous branches of the liver were visualized separately during one sequential aortogram. The minimum diameter of the vessels observed was approximately 20 microm, and the vessels which ran parallel to the hepatic artery were observed and it seemed to be intrahepatic peribiliary arterial plexus. CONCLUSIONS: Our new experimental model would be useful for visualization of changes in the hepatic microcirculation under nearly physiologic conditions.     

Early stage gastric MALT lymphoma with high-grade component cured by Helicobacter pylori eradication

A 68-year-old woman was diagnosed with gastric lymphoma of the mucosa-associated lymphoid tissue (MALT) type with a high-grade component. Surgical treatment was recommended because of the presence of the high-grade component, but she refused surgery. As an alternative, she received Helicobacter pylori eradication treatment, which successfully induced regression of the lymphoma. She shows no sign of recurrence endoscopically and histologically, as of 29 months after the eradication treatment. Moreover, the B-cell monoclonality and Helicobacter pylori infection demonstrated at diagnosis has disappeared. This is one of the rare cases of gastric lymphoma of the MALT type with a high-grade component cured by Helicobacter pylori eradication alone. Received: October 7, 1999 / Accepted: May 26, 2000     

Surgical experience with right atrial-aortic fistula and penetration of the superior vena cava by a protruding Accufix atrial J-shaped retention wire.

A 57-year-old woman who had a dual chamber pacemaker implanted in June 1990 for sick sinus syndrome had developed heart failure since 1993. Although fluoroscopy revealed that the proximal J-shaped retention wire of the lead had fractured and had protruded through the outer insulation in 1994, and also that the distal J-shaped retention wire of the lead had protruded through the outer insulation in 1997, a transthoracic echocardiographic examination diagnosed tricuspid valve regurgitation, suggesting that the right atrial-aortic fistula might have been overlooked. In an attempt to avoid migration of the J-shaped retention wire from the lead and to repair the tricuspid regurgitation, it was decided that an operation be performed; however, intraoperative transesophageal echocardiography showed a right atrial-aortic fistula. Intraoperative inspection also revealed that the right atrial-aortic fistula and penetration of the superior vena cava had been caused by the Accufix atrial J-shaped retention wire. Under total cardiopulmonary bypass and induced cardiac arrest, a right atriotomy was performed and the atrial and ventricular leads were removed from the tips. The atrial orifice of the fistula and the aortic orifice were closed. Finally, a new dual-chamber pacing system with bipolar epicardial pacing leads was implanted. Postoperative inspection revealed that the proximal retention wire had fractured, the tip of the retention wire had protruded through the outer insulation, and the distal J-shaped outer insulation was damaged.     

Impact of MRI-based postimplant dosimetric assessment in prostate brachytherapy using contrast-enhanced T1-weighted images

PurposeTo compare contrast-enhanced T1-weighted (CE-T1WI) magnetic resonance imaging (MRI) with computed tomography (CT) for postimplant dosimetry and seed recognition in prostate brachytherapy.Methods and MaterialsA total of 245 patients who received ¹²⁵I prostate brachytherapy with or without external beam radiotherapy were enrolled. For postimplant analysis, CT and MRI scans were obtained at 1 month after seed implantation. For MRI-based dosimetry, T2-weighted images were fused with the CE-T1WI; the prostate was delineated on the T2-weighted images, and the seed detection was performed manually on the CE-T1WI. In CT-based dosimetry, the seed detection was essentially performed automatically. The dosimetric results obtained by MRI-based and CT-based dosimetry were compared.ResultsThe mean prostate D₉₀ (the minimum dose received by 90% of the prostate volume) estimated by MRI-based and CT-based dosimetry were 113% and 115%, respectively, with no significant difference. The mean prostate V₁₀₀ (the percent volume of the postimplant prostate receiving 100% of the prescribed dose) estimated by MRI-based and CT-based dosimetry were 95.2% and 95.8%, respectively, again with no significant difference. The mean prostate V₁₅₀ (the percent volume of the postimplant prostate receiving 150% of the prescribed dose) estimated by MRI-based and CT-based dosimetry were 52.8% and 57.0%, respectively (p < 0.01). In all of the 35 patients (14%) in whom the MRI-based V₁₅₀ were at least 10% lower than the CT-based results, the seed detection by CT-based dosimetry was overestimated in highly seed-clustered areas or in the areas close to calcifications because of reconstruction artifacts in CT images.ConclusionsMRI-based dosimetry using CE-T1WI appears to be acceptable. Our results suggest that MRI-based dosimetry is a practical method for estimation of the higher dose distribution, especially if seeds are clustered together or when they are close to calcifications.     

Fatal tumoral hemorrhage after stereotactic radiosurgery for metastatic brain tumors: report of three cases and review of literature

Acute tumor hemorrhage occurring during stereotactic radiosurgery (SRS) for a metastatic lesion, or in the immediate post-treatment period, is believed to be extremely rare. The potential risk of hemorrhage related to SRS procedures in patients with metastatic brain tumors is not yet clearly understood. This case report describes three patients suffering acute fatal tumor hemorrhage during or immediately after SRS. One patient died within 2 weeks of treatment and the other patients were severely disabled as a result of the hemorrhage. The incidence of this complication was estimated as 0.52% per patient, 0.33% per intervention and 0.08% per lesion by reviewing our research database. Metastases from renal cell carcinoma, evidence of pre-radiosurgical peritumoral oozing of blood, anti-coagulant and anti-platelet therapy were likely to be associated with tumor hemorrhage. Although this life-threatening complication is uncommon, extra caution should be exercised when treating patients with factors that could predispose to tumoral hemorrhage.     

A case report on a patient with inflammatory pseudotumor of the bladder

A 43-year-old man was referred to our hospital with a bladder tumor, which was incidentally found by abdominal ultrasonography in a health examination. Cystoscopy and magnetic resonance imaging showed a 3 cm submucosal bladder tumor localized at the top of the bladder. We performed transurethral resection of bladder tumor. Histopathological features was inflammatory tumor of urinary bladder. No local recurrence was seen 6 months after surgery.     

Successful gemcitabine-nedaplatin therapy in a hemodialysis patient with ureteral carcinoma after bilateral nephroureterectomy

A 79-year-old male, who received hemodialysis due to bilateral nephroureterectomy and cysto-prostateurethrectomy. Five months later, an enlarged lymph node was found in the left of inguinal area. Abdominal computed tomography revealed a low density mass from the para-aortic lymph node to the left of inguinal area, suggesting lymph node metastasis of ureteral carcinoma. After 3 cycles of gemcitabinenedaplatin therapy, the size of lymph node metastasis decreased. This is a report of successful treatment of ureteral carcinoma with hemodialysis.     

Torsion of the Gallbladder Diagnosed by Magnetic Resonance Cholangiopancreatography

Torsion of the gallbladder is a rare entity that is difficult to diagnose preoperatively, the principal differential diagnosis being cholecystitis. The condition occurs most often in the elderly. Although its etiology is unknown, the presence of a redundant mesentery is a prerequisite for torsion. Computed tomography, ultrasound, and magnetic resonance cholangiopancreatography can provide important diagnostic clues. Torsion of the gallbladder occurs when it twists axially, with subsequent occlusion of bile or blood flow. Therefore, prompt surgical treatment is necessary in order to prevent necrosis and perforation. In the present study, we report a case of torsion of the gallbladder diagnosed by magnetic resonance cholangiopancreatography. This condition was successfully treated by laparoscopic cholecystectomy.