Assessment of dural arteriovenous fistulas of the cavernous sinuses on 3D dynamic MR angiography.

BACKGROUND AND PURPOSE: Flow voids within the cavernous sinuses and/or certain venous drainage on spin-echo MR imaging and time-of-flight (TOF) flow enhancement on MR angiography (MRA) have indicated high-velocity shunt flow and have been used for screening patients with dural arteriovenous fistulas (DAVFs) of the cavernous sinuses. In this investigation, the capabilities of 3D dynamic MRA as a flow-independent approach and those of conventional MR imaging techniques were compared with selective angiography for the diagnosis of DAVFs of the cavernous sinuses. MATERIALS AND METHODS: This retrospective study involved 18 patients with angiographically proved DAVFs of the cavernous sinuses and 12 control subjects. Sixteen partially overlapping sequential MR images were acquired on contrast-enhanced 3D dynamic MRA between the petrosal bone and the orbital roof. Two experienced observers blinded to the clinical data and results of angiography independently graded 3D dynamic MRA, fast spin-echo T2-weighted imaging (FSE T2WI), and TOF MRA. RESULTS: The average area under the receiver operating characteristic curve values and interobserver kappa scores for the diagnosis of DAVFs on 3D dynamic MRA, FSE T2WI, and TOF MRA were 0.99, 0.89, and 0.95; and 0.92, 0.71, and 0.73, respectively. Those for the diagnosis of anterior, posterior, and retrograde cortical venous drainage on 3D dynamic MRA were 0.72, 0.95, and 0.81; and 0.56, 0.50, and 0.49, respectively. CONCLUSION: In this small series, screening 3D dynamic MRA directly demonstrates DAVFs of the cavernous sinuses and has improved diagnostic capability.

Arteriovenous malformations: ethanolamine oleate sclerotherapy.

Peripheral vascular malformations are now described according to some accepted guidelines, and the principle of proper treatment (nodus ablation) is becoming clear. An appropriate classification schema for vascular anomalies and definite indications for treatment are important to successful treatment overall. Non-invasive imaging (US, CT, and MRI) in association with clinical findings is critical in establishing the diagnosis, evaluating the extent of the malformation, and planning appropriate treatment. Direct nidus phlebography is useful not only in making a correct diagnosis but also in treating the lesion by sclerotherapy. When a patient suffers clinical complications, the nidus sclerotherapy becomes mandatory. If the vascular malformation remains bloodstream to a drainage vein during nidus opacification, flow control is necessary to achieve complete nidus ablation. A multidisciplinary approach is needed in the treatment of a high-flow lesion. A dedicated team approach is necessary for appropriate management in most cases.

Thoracic stent-graft.

The stent-graft is a device constructed from a stent and vascular graft and is inserted by means of an interventional procedure under imaging guidance. In 1986, Balko et al. reported the first stent-graft experiment, in which a Z stent covered with polyurethane was inserted into an animal aorta. In the early 1990s, Parodi et al. reported clinical introduction of the stent-graft for abdominal aortic aneurysm. In comparison to the abdominal aortic stent-graft, the thoracic stent-graft has several disadvantages, including difficulties associated with the aortic arch curvature and the relatively large caliber of the stent-graft, and the risk of central nervous system or spinal complication. However, the thoracic stent-graft is advantageous because of minimal procedural invasiveness in comparison to surgical graft replacement. In 1994, Dake et al. reported transluminal placement of an endovascular stent-graft for thoracic aortic aneurysm, and Kato et al. reported use of a stent-graft for aortic dissection and suggested that the stent-graft could be considered an alternative to surgical treatment.

Significance of distal fenestration in graft replacement for chronic aortic dissection.

It is recently controversial whether distal fenestration is necessary in graft replacement for chronic aortic dissection. Several groups started to try the exclusion of intimal entry by the insertion of a stent-graft as a treatment for chronic aortic dissection, while conventional surgical techniques consisted of graft replacement with distal anastomosis to both the true and false channels. It should be kept in mind that the resultant occlusion of the false lumen after obliteration of the false channel could promote spinal cord ischemia. We report a patient with delayed paraplegia after graft replacement without distal fenestration for chronic type B aortic dissection. It is possible that not all cases of chronic aortic dissection are good for stent-grafting.

Usefulness of magnetic resonance imaging for surgical management of extravasation of an antitumor agent: a case report.

We report a case of extravasation of an antitumor agent by preoperative magnetic resonance (MR) imaging. MR studies demonstrated a decreased signal intensity on T1- and T2-weighted images and a strong enhancement of contrast media in injured tissue, including subcutaneous adipose tissue and deep fascia, which was cicatrical macroscopically. The MR findings were in good agreement with the macroscopic findings. We believe that MR imaging is useful for estimating deep tissue damage due to extravasation of an antitumor agent.

Post-traumatic high flow priapism: demonstrable findings of penile enhanced computed tomography.

Post-traumatic high flow priapism is a rare disease. A review of English published reports revealed 63 cases. Enhanced computed tomography (CT) of the penis has not previously been used as a diagnostic method for post-traumatic high flow priapism. We present a case of post-traumatic high flow priapism diagnosed with enhanced CT of the penis. Additionally, diagnostic modalities for post-traumatic high flow priapism are discussed with review of published work.

High-flow arteriovenous malformation of the lower extremity: ethanolamine oleate sclerotherapy.

We report the case of a young man presenting with high-flow arteriovenous malformation (AVM), in whom percutaneous direct nidus puncture ethanolamine oleate (EO) sclerotherapy was useful in the management of the AVM. To our knowledge, this is the first report of percutaneous trans-nidus EO sclerotherapy for AVM in the extremities. Percutaneous trans-nidus sclerotherapy should be considered as an alternative choice for the management of symptomatic AVM.

Prenatal MRI in a fetus with a giant neck hemangioma: a case report.

We report a fetus with a giant neck hemangioma which was examined by MRI in utero. The initial diagnosis was made by ultrasonography. The sonolucent aspect of the mass, together with the presence of pulsating Doppler flow signals, was highly suggestive of a fetal hemangioma. In late pregnancy, fetal MRI revealed the location, size and characteristics of the neck tumor. Following prenatal corticosteroid treatment and premature delivery of the pregnancy due to fetal cardiac failure, the newborn received angiography and coil embolization of the tumor vessels. Despite vigorous treatments, the newborn died 12 h after birth. Evaluation of a fetal neck hemangioma by MRI is recommended late in pregnancy for precise information on the tumor and adjacent organs since the image is valuable for planning optimal perinatal treatment.

Use of fusion images of I-131 metaiodobenzylguanidine, SPECT, and magnetic resonance studies to identify a malignant pheochromocytoma.

Pheochromocytoma is a chromaffin tumor in which 10% are extra-adrenal and 10% are malignant. I-131 metaiodobenzylguanidine (MIBG) scintigraphy has an important role in the identification of these tumors and investigation of metastatic lesions. The authors describe a 36-year-old woman who underwent resection of a malignant left adrenal pheochromocytoma who was thought to have metastases in the liver and para-aortic lymph nodes. Fusion images of I-131 MIBG SPECT and magnetic resonance studies were obtained to properly identify the metastatic lesions. These fusion images helped greatly in subsequent surgery.

Microwave coagulation therapy: ex vivo comparison of MR imaging and histopathology.

We compared the findings of magnetic resonance (MR) images and pathological examination to determine whether or not MR images reflect pathological changes following microwave coagulation therapy (MCT) on liver tissue. We used microwave (generating frequency 2450 Mhz, wave length 12 cm, output 50 W, 60 second duration) to irradiate six canine livers under general anesthesia. After the animals were sacrificed, the livers were resected. The irradiated regions were cut with margins and divided into two pieces, one for MR study, and the other for pathological examination. The findings were compared. From the center to the marginal layer, the irradiated region presented 4/3 laminal patterns on T1/T2-weighted images: low/high, high/low, very high/high, and iso-low/high intensity. On gradient-echo imaging, the irradiated regions presented no decreasing signals using several echo time lengths. With hematoxylin and eosin stain, MR laminar patterns reflected the histopathological changes, as follows: a tissue loss area surrounding the inserted needle, low/high; decreased sinusoidal width with/without necrotic tissue, high/low; sinusoidal width dilation at the periphery, very high/high; and fatty degenerated tissue surrounding the irradiated area at the boundary of the normal hepatocytes, iso-low/high. The MR signal intensity, which reflected the histopathological changes, presented tissue characterization after MCT, and the macromolecular hydration effect influenced the high intensity on T1-weighted images.

Venous sac embolization of pulmonary arteriovenous malformation: preliminary experience using interlocking detachable coils.

PURPOSE: To evaluate the indication and advantages of venous sac embolization of pulmonary arteriovenous malformations (PAVMs) using interlocking detachable coils (IDCs). METHODS: We performed percutaneous embolization in 12 PAVMs in four patients using IDCs, initially placed in the venous sac or at the feeding artery to prevent systemic migration of additional coils. We placed the IDCs in the venous sac in PAVMs with the following vascular architecture: the draining vein was larger than the feeding arteries and both vessels were interposed with the venous sac or there were short feeding arteries. RESULTS: Complete occlusion was achieved in all 12 PAVMs without significant complications. We deployed IDCs in the venous sac in eight PAVMs and in the feeding artery in four. CONCLUSION: Venous sac embolization may be beneficial in PAVMs with large out-flow vessels or short feeding arteries. IDCs are suitable for this procedure.

Microwave coagulation therapy on hepatomas: CT and MR appearance after therapy.

Laparoscopic microwave coagulation (LMC) for hepatocellular carcinomas (HCCs) was performed on 26 HCCs in 17 patients. Contrast-enhanced CT (CECT) and MR images (T1-weighted imaging [T1WI], T2WI, gadolinium-diethylenetriamine pentaacetic acid [Gd-DTPA] T1WI) were obtained to determine changes over time. The irradiated center exhibited low to moderate intensity with surrounded high intensity (HI) on T2WI and Gd-DTPA T1WI. On T1WI, lesions showed four patterns of intensity: uniform HI (30.8%), arcuate HI (26.9%), mainly low with spot HI (30.8%), and isointensity to hypointensity (11.5%). Follow-up imaging at more than 170 days revealed isointensity to hypointensity on T1WI (96.2%) and reduced HI on T2-weighted imaging (T2WI) and Gd-DTPA T1WI. All lesions became less conspicuous and were reduced in volume. HCC shows time-related changes in signals and size after LMC. Identifying the irradiated lesion is necessary to estimate the adequacy of treatment by comparison with the pretherapeutic image.

Three-dimensional CT imaging of an isolated dissecting aneurysm of the superior mesenteric artery.

A case of an isolated dissecting aneurysm of the superior mesenteric artery is presented with findings of three-dimensional CT imaging. False lumen, intimal flap, entry, and re-entry are clearly identified on three-dimensional CT imaging.

High level cross of the esophagus with the descending aorta in scoliosis: CT study.

OBJECTIVE: The esophagus occasionally crosses the descending aorta at an unusually high level (3-5 cm inferior to the carina) in right-sided scoliosis. The purpose of this study was to analyze the mechanism of this finding. MATERIALS AND METHODS: We prospectively evaluated thoracic CT scans in 30 patients with right-sided scoliosis. We assessed the alterations in the positions of the esophagus and the descending aorta by the thoracic deformity. RESULTS: The descending aorta followed the scoliotic curve of the spine in 26 (87%) patients. The esophagus followed the scoliotic curve of the spine in 14 (47%) patients and did not in 16 (53%). The anteroposterior diameter of the thorax in the former group was significantly smaller than that in the latter (p < 0.01). High level cross of both structures was identified in 14 (47%) patients, and all of them belonged to the group in which the esophagus did not follow the scoliotic curve of the spine. CONCLUSION: The unusual high level cross of the esophagus with the descending aorta occasionally seen in scoliosis is due to a difference in the positional alterations of the two structures resulting from the scoliosis.

[Accelerated hyperfractionation in the treatment of malignant glioma].

A retrospective evaluation was performed to determine whether accelerated hyperfractionation (AHF) improves the survival rate of patients with malignant gliomas. One hundred and seven patients with malignant gliomas, including glioblastoma multiforme, who had received radical radiotherapy were evaluated. Of the patients, 36 were treated by conventional fractionation (CF), and 71 by AHF. The treatment results of the two regimens were compared with regard to survival rate after therapy. Treatment by AHF was conducted at 10-15 F/W (1.5 Gy/F); the mean total dose was 61 Gy over an average of 27 days. Treatment by CF was conducted at 5 F/week (1.8-2 Gy/F); the mean total dose was 59 Gy over 51 days. Multivariate analysis using Cox's proportional hazard model revealed that AHF significantly increased survival rate. Besides pointing to the selection of the AHF method as a treatment regimen, multivariate analysis showed the following factors to be indicators of favorable prognosis: a histopathological diagnosis other than glioblastoma multiforme, age below 40 years, and supratentorial location of the tumor.