Yoshiyuki Nomura

MR assessment of normal brain development in neonates and infants : Comparative study of T1- and diffusion-weighted images

PURPOSE This study was designed to compare the sensitivity of T1- and diffusion-weighted images for the assessment of brain maturation in human brains. METHODS T1- and diffusion-weighted images were obtained in 32 children without neurological abnormalities or growth retardation. The ages at which signal intensity changes of white matter on T1-weighted images and diffusional anisotropy appeared were compared. RESULTS In the optic radiation, diffusional anisotropy was observed in neonates < 1 month old, whereas signal intensity became high after 1 month old. In the frontal lobe, diffusional anisotropy began to appear after 1 month of age, but signal intensity became high after 6 months of age. These visual findings were confirmed statistically by quantitative analysis using signal intensity ratios and anisotropic ratios. Similar findings were observed in the external capsule and the genu of the corpus callosum. CONCLUSION In conclusion, diffusional anisotropy is a sensitive indicator of brain maturation in neonates and infants and precedes signal intensity change on T1-weighted images.

Relief of Mesenteric Ischemia by Z-Stent Placement into the Superior Mesenteric Artery Compressed by the False Lumen of an Aortic Dissection

In a 58-year-old man acute aortic dissection compromised the origin of the superior mesenteric artery (SMA), resulting in mesenteric ischemia. After failed balloon angioplasty a Gianturco Z-stent was placed. The stenosis improved immediately, followed by resolution of the clinical signs of mesenteric ischemia. SMA flow was well preserved 1 year after stenting.

Treatment of chronic type B aortic dissection with endovascular stent-graft placement

A 74-year-old man with chronic aortic dissection was treated with an endovascular stent graft, fabricated from expanded polytetrafluoroethylene and a Z-stent. It was placed in the true lumen to close an entry tear. Closure was obtained immediately and thrombosis of the false lumen at the descending thoracic aorta was observed on computed tomography (CT) obtained 1 week later. No procedure-related complications developed. The patient is doing well with no adverse events including aortic rupture or aortic branch ischemia.

Three-dimensional coronary magnetic resonance angiography with injection of extracellular contrast medium.

RATIONALE AND OBJECTIVES To evaluate serial changes of the signal intensity and the contrast-to-noise ratios of the coronary arteries on three-dimensional (3D) coronary magnetic resonance angiography (MRA) after an injection of extracellular contrast medium, and to demonstrate the feasibility of this method for the diagnosis of coronary artery abnormalities. METHODS Five healthy volunteers and two patients with Kawasaki disease and an anomalous coronary artery were studied. Coronary MRAs of the left anterior descending artery and the right coronary artery were obtained using a fat-suppressed 3D MRA sequence before and 0 to 5, 10 to 15, 20 to 25, and 30 to 35 minutes after administration of Gd-DTPA-BMA. RESULTS Administration of the contrast agent provided a significant increase in the signal intensity and contrast-to-noise ratio. Aneurysm of the left anterior descending artery in Kawasaki disease and the proximal course of the anomalous right coronary artery, which were not well depicted on precontrast 3D MRA, were clearly demonstrated after contrast injection. CONCLUSIONS The current study demonstrated that the use of an extracellular gadolinium contrast agent can significantly improve the clinical usefulness of 3D coronary MRA.

Magnetic resonance imaging of synovial proliferation in temporomandibular disorders with pain.

Objective: The objective of this study was to assess the clinical significance of synovial proliferation in patients with painful temporomandibular disorders based on magnetic resonance imaging findings. Methods: The current study was conducted in 100 joints of 100 patients with unilateral painful temporomandibular disorders. One hundred joints on the contralateral side of patients with unilateral disease were used as nonpain group. Areas in the articular space that showed a low signal intensity on T1-weighted imaging, a high signal intensity on T2-weighted imaging, and high signal intensity on gadolinium-enhanced fat-suppressed T1-weighted imaging were judged to be regions of synovial proliferation. Results: Synovial proliferation alone was observed in 8.0% of the pain group, but in none of the nonpain group. Synovial proliferation + effusion was observed in 33.0% of the pain group and in 7.0% of the nonpain group. Effusion alone was observed in 7.0% of the pain group and in 3.0% of the nonpain group. The mean visual analog scale value of pain was in the order of synovial proliferation alone > synovial proliferation + effusion > effusion alone. The incidence rates of anterior displacement of the disk were 100% for synovial proliferation alone, 93.9% for synovial proliferation + effusion, 57.1% for effusion alone, and 57.7% for “without synovial proliferation/effusion.” Conclusions: Strong correlations were observed between synovial proliferation, pain, and disk displacement. It is considered that evaluating effusion alone provides only limited information on the disease state in painful temporomandibular disorders. Thus, it is essential to include enhanced T1-weighted imaging as a means to judge the disease state as well as to assess disease progression.

Radiofrequency ablation for the treatment of hemorrhagic vaginal cancer.

Editor: Radiofrequency (RF) ablation has attracted a great deal of interest as a method for the treatment of various malignancies (1–3). In this report, we present a case of hemorrhagic vaginal cancer that was successfully treated by RF ablation. A 74-year-old woman visited our hospital with vaginal bleeding and severe anemia in April 2002. She had vaginal prolapse and a prominent hemorrhagic vaginal tumor with a maximum diameter of 15 cm. The vaginal tumor had invaded the urinary bladder and caused vesicovaginal fistula (Figure, part a). The vaginal tumor was proven by biopsy to be vaginal cancer of clinical stage IVA. The patient was judged to not be a candidate for surgical intervention because of her poor general condition. Although systemic chemotherapy and transarterial embolization of the internal iliac arteries were performed, the tumor became larger and tumor bleeding continued. Then, vaginal RF ablation was performed with epidural anesthesia five times during a 4-month period. The urinary bladder was continuously irrigated with cold saline solution via a three-channel urinary catheter to protect the bladder wall. A straight 17-gauge cooled-tip RF electrode (Radionics, Burlington, MA) was placed at three to six different sites during each RF session under computed tomographic fluoroscopic or ultrasound guidance. The first two RF procedures were performed in the supine position, but skin burns developed in the femoral region at the time of the second RF ablation session. The next three RF sessions were performed in the lithotomy position. To separate the vaginal tumor from the femoral skin, surgical gloves stuffed with gauze were placed between the tumor and the skin. Tumor bleeding ceased and the maximum tumor size was reduced from 15 cm to 4 cm after the fifth RF session (Figure, part b). The skin burns resolved with symptomatic treatment. The vesicovaginal fistula had become apparent as a result of shrinkage of the vaginal tumor, but the patient did not develop any complications such as uriDOI: 10.1097/01.RVI.0000188777.69563.AA