Dural arteriovenous fistulas involving the superior sagittal and parasagittal sinuses: clinical presentation, imaging characteristics and treatment strategies

BACKGROUND AND PURPOSE

Dural arteriovenous fistulas (DAVFs) involving the superior sagittal (SSS) and parasagittal sinuses are often inappropriately classified. We explore the clinical presentations, imaging characteristics and endovascular treatment strategies these two DAVF subtypes.

MATERIALS AND METHODS

Clinical and imaging data of 19 patients with SSS or parasagittal sinus DAVFs who underwent endovascular treatment in our institution from 2017 and 2022 were retrospectively analyzed. The angiographic findings, endovascular treatment strategies and angiographic outcomes were evaluated and recorded.

RESULTS

Among these 19 patients, 14 had a parasagittal DAVF, 4 had a SSS DAVF, one patient had both a parasagittal and SSS DAVF. Only one (1/19, 5.26%) patient presented with intracranial haemorrhage (ICH); For the parasagittal DAVF group, most of the shunts were located along the middle third of the SSS (12/15, 80%), on the dura in proximity with the junctional zone between the bridging vein and SSS (15/15, 100%), with ipsilateral cortical venous reflux (CVR) (15/15, 100%). For the SSS DAVF group, all 5 patients had shunting zone along the middle third of the SSS, on the sinus or parasinus wall, with bilateral CVR. Trans-arterial embolization, via the middle meningeal artery (MMA) as the primary route of access, was the primary treatment approach in 95% of cases (19/20). Reflux of embolization material into the SSS was observed in one case (1/5, 20%) of SSS DAVF in which balloon sinus protection was not used during embolization.

CONCLUSIONS

Our study found that parasagittal DAVFs have shunting point(s) centred on the junctional zone of the bridging vein and the SSS with ipsilateral CVR, while SSS DAVFs have shunting point(s) centred on the sinus or parasinus wall with bilateral CVR. Trans-arterial embolization via the MMA(s) can be used as the primary treatment strategy in most cases. Balloon sinus protection during embolization is not necessary in cases of parasagittal DAVF with occluded or stenosed connection with the SSS but its use should be considered in cases of SSS DAVF with patent sinus.

ABBREVIATIONS

DAVF, Dural arteriovenous fistula; SSS, Superior sagittal sinus; CVR, Cortical venous reflux; MMA, middle meningeal artery; ICH, Intracranial haemorrhage; STA, Superficial temporal artery; OA, Occipital artery. CFD, Computational fluid dynamics.

Petrobasal Vein: A Previously Unrecognized Vein Directly Connecting the Superior Petrosal Sinus with the Emissary Vein of the Foramen Ovale

BACKGROUND AND PURPOSE

The superior petrosal sinus terminates anteriorly at the cavernous sinus and posteriorly at the transverse sinus. Venous variations directly connecting the superior petrosal sinus and the emissary veins of the foramen ovale are not well-recognized. We present a connecting vein, provisionally named the petrobasal vein.

MATERIALS AND METHODS

Biplane cerebral angiography of the bilateral internal carotid arteries and the vertebral artery acquired in 267 patients was retrospectively reviewed by 2 neuroradiologists with special interest in the existence and course of the petrobasal vein.

RESULTS

The petrobasal vein was observed to lie anterior-posteriorly on the superior surface of the petrosal bone and connected to the midportion of the superior petrosal sinus and the emissary veins of the foramen ovale in 41 patients (15%) and sides (7.9%); it drained into the pterygoid plexus. The petrobasal vein was observed on VAG in 21 patients, on ICAG alone in 8 patients (9 sides), on both VAG and ICAG in 12 patients, and on ICAG in 1 patient. In the patients in whom the petrobasal vein was visualized on the ICAs, the superficial middle cerebral vein drained into a combination of the pterygoid plexus via the emissary veins of the foramen ovale and the superior petrosal sinus.

CONCLUSIONS

The petrobasal vein, an unknown vein directly connecting the superior petrosal sinus and the emissary veins of the foramen ovale and draining into the pterygoid plexus, can occasionally be identified on cerebral angiography as a variant drainage route from the cerebellum and brainstem veins and/or from the superficial middle cerebral vein. The petrobasal vein is thought to be a remnant of the primitive tentorial sinus.

Artery of the Superior Orbital Fissure: An Undescribed Branch from the Pterygopalatine Segment of the Maxillary Artery to the Orbital Apex Connecting with the Anteromedial Branch of the Inferolateral Trunk

BACKGROUND AND PURPOSE

Some branches of the internal maxillary artery have anastomoses with the inferolateral trunk that are important as intracranial-extracranial collateral pathways and as dangerous anastomoses for transarterial embolization of these branches. We present here an undescribed branch potentially anastomosing with the anteromedial branch of the inferolateral trunk, which is provisionally named the artery of the superior orbital fissure, defined as an arterial branch from the pterygopalatine segment of the maxillary artery to the orbital apex at the superior orbital fissure.

MATERIALS AND METHODS

Two neuroradiologists reviewed 3D and MPR images of the external and/or common carotid artery with particular interest paid to the artery of the superior orbital fissure in 54 patients who underwent 3D angiography with a field of view covering the pterygopalatine fossa and the cavernous sinus. The underlying diseases in these patients were 17 parasellar hypervascular lesions (including 13 cavernous sinus dural arteriovenous fistulas and 4 meningiomas), 18 internal carotid artery stenoses/occlusions, and 19 other diseases.

RESULTS

The artery of the superior orbital fissure was identified in 20 of 54 patients; it arose at the pterygopalatine segment of the maxillary artery, either singly or from a common trunk with the artery of the foramen rotundum, and ran upward to reach the superior orbital fissure. It anastomosed with the anteromedial branch of the inferolateral trunk at the superior orbital fissure with blood flow toward the cavernous sinus (n = 14) and/or the ophthalmic artery (n = 2). It was more prominent in parasellar hypervascular lesions and internal carotid artery stenoses/occlusions than in other diseases.

CONCLUSIONS

The artery of the superior orbital fissure, a remnant of the anastomotic artery, was often identified, especially in patients with parasellar hypervascular lesions.

Angioarchitecture of transverse-sigmoid sinus dural arteriovenous fistulas: evaluation of shunted pouches by multiplanar reformatted images of rotational angiography

BACKGROUND AND PURPOSE

Recognition of shunted pouches dural arteriovenous fistula allows us to treat the disease effectively by selective embolization of the pouches at first. However, the shunted pouches in transverse-sigmoid sinus dural arteriovenous fistulas have not been well-documented. Our aim was to evaluate the angioarchitecture of transverse-sigmoid sinus dural arteriovenous fistulas, including the frequency and location of shunted pouches and their feeding arteries. MATERIALS AND METHODS Twenty-five consecutive cases of TSS-DAVFs that underwent rotational angiography and transvenous embolization between 2008 and 2011 were reviewed. Multiplanar reformatted images of rotational angiography and selective angiography were reviewed with a particular focus on the shunted pouches.

RESULTS

All 25 cases showed SPs, with numbers ranging from 1 to 4 pouches (mean, 2.35). The SPs were located at the transverse-sigmoid junction in 16, close to the vein of Labbé in 9, at the dorsal-to-sigmoid sinus in 9, inferior to the sigmoid sinus in 6, at the sigmoid-jugular junction in 5, and inferior to the transverse sinus or the sinus confluence in 14. The SP at the sigmoid sinus was frequently fed by the jugular branch of the ascending pharyngeal artery and the stylomastoid artery. The SP at the transverse-sigmoid junction and the vein of Labbé was fed by the petrosal/petrosquamous and posterior branches of the middle meningeal artery and the transosseous branches of the occipital artery. The SP inferior to the transverse sinus and the sinus confluence was fed by the transosseous branches of the occipital artery and the posterior meningeal artery. All cases were successfully treated by transvenous embolization with sinus packing (n = 13) or selective embolization of the SP (n = 12).

CONCLUSIONS

The presence of SP is a common angioarchitecture of TSS-DAVFs. Identification of the SPs would be useful for their treatment.

Superior petrosal sinus: hemodynamic features in normal and cavernous sinus dural arteriovenous fistulas

BACKGROUND AND PURPOSE

Normal hemodynamic features of the superior petrosal sinus and their relationships to the SPS drainage from cavernous sinus dural arteriovenous fistulas are not well known. We investigated normal hemodynamic features of the SPS on cerebral angiography as well as the frequency and types of the SPS drainage from CSDAVFs.

MATERIALS AND METHODS

We evaluated 119 patients who underwent cerebral angiography by focusing on visualization and hemodynamic status of the SPS. We also reviewed selective angiography in 25 consecutive patients with CSDAVFs; we were especially interested in the presence of drainage routes through the SPS from CSDAVFs.

RESULTS

In 119 patients (238 sides), the SPS was segmentally (anterior segment, 37 sides; posterior segment, 82 sides) or totally (116 sides) demonstrated. It was demonstrated on carotid angiography in 11 sides (4.6%), receiving blood from the basal vein of Rosenthal or sphenopetrosal sinus, and on vertebral angiography in 235 sides (98.7%), receiving blood from the petrosal vein. No SPSs were demonstrated with venous drainage from the cavernous sinus. SPS drainage was found in 7 of 25 patients (28%) with CSDAVFs. CSDAVFs drained through the anterior segment of SPS into the petrosal vein without draining to the posterior segment in 3 of 7 patients (12%).

CONCLUSIONS

The SPS normally works as the drainage route receiving blood from the anterior cerebellar and brain stem venous systems. The variation of hemodynamic features would be related to the relatively lower frequency and 2 different types of SPS drainage from CSDAVFs.

Turn-back embolization technique for effective transvenous embolization of dural arteriovenous fistulas

For effective transvenous embolization of DAVFs, it is important to place coils at the shunting venous pouch in the initial step of the procedure. When it was difficult to navigate a microcatheter to the shunting venous pouch due to the anatomic relationship of approach routes with targeted pouches, we navigated the microcatheters by a "turn-back technique" within the involved sinuses into the target pouches. Complete occlusion or regression of the DAVF was obtained in all cases.

Venous structures at the craniocervical junction: anatomical variations evaluated by multidetector row CT

The aim of this study was to evaluate the anatomy of and normal variations in the craniocervical junction veins. We retrospectively reviewed 50 patients who underwent contrast-enhanced CT with a multidetector scanner. Axial and reconstructed images were evaluated by two neuroradiologists with special attention being paid to the existence and size of veins and their relationships with other venous branches around the craniocervical junction. The venous structures contributing to craniocervical junction venous drainage, including the inferior petrosal sinus (IPS), transverse-sigmoid sinus, jugular vein, condylar vein, marginal sinus and suboccipital cavernous sinus were well depicted in all cases. The occipital sinus (OS) was identified in 18 cases, including 4 cases of prominent-type OS. The IPS showed variations in drainage to the jugular vein through the jugular foramen or intraosseous course of occipital bone via the petroclival fissure. In all cases, the anterior condylar veins connected the anterior condylar confluence to the marginal sinus; however, a number of cases with asymmetry and agenesis in the posterior and lateral condylar veins were seen. The posterior condylar vein connected the suboccipital cavernous sinus to the sigmoid sinus or anterior condylar confluence. The posterior condylar canal in the occipital bone showed some differences, which were accompanied by variations in the posterior condylar veins. In conclusion, there are some anatomical variations in the venous structures of the craniocervical junction; knowledge of these differences is important for the diagnosis and treatment of skull base diseases. Contrast-enhanced CT using a multidetector scanner is useful for evaluating venous structures in the craniocervical junction.

Dural arteriovenous fistula involving the posterior condylar canal

Although dural arteriovenous fistulas (DAVFs) occur in any structure that is covered by the dura mater, DAVFs at the posterior condylar canal have not been reported. We present a DAVF that involves the posterior condylar canal and drains into the posterior condylar vein and the occipital sinus, which was treated by selective transvenous embolization. Knowledge of venous anatomy of the craniocervical junction and careful assessment of the location of the arteriovenous fistula can contribute to successful treatment.

Selective transvenous embolization of dural arteriovenous fistulas involving the hypoglossal canal

SUMMARY

The hypoglossal canal contains a venous plexus that connects the inferior petrous sinus, condylar vein, jugular vein and paravertebral plexus. The venous plexus is one of the venous drainage routes of the posterior skull base. Only a few cases of dural arteriovenous fistulas (AVFs) involving the hypoglossal canal have been reported. We describe three cases (a 62-year-old female, a 52-year-old male, and an 83-year-old male) of dural AVFs involving the hypoglossal canal. Symptoms were pulse-synchronous bruit in two cases and proptosis/chemosis in one. All dural AVFs were mainly fed by the ipsilateral ascending pharyngeal artery. Two of three dural AVFs involving the hypoglossal canal mainly drained through the anterior condylar confluence into the inferior petrosal sinus retrogradely with antegrade drainage through the lateral condylar vein. The other one drained through the lateral and posterior condylar veins into the suboccipital cavernous sinus. All dural AVFs were completely occluded by selective transvenous embolization without any complications, and the symptoms disappeared within one week in all cases. Dural AVFs involving the hypoglossal canal can be successfully treated by selective transvenous embolization with critical evaluation of venous anatomy in each case.

Inferior mesenteric veno-caval shunt: imaging features and interventional treatment

AIM

To describe the imaging features of inferior mesenteric vein (IMV)-inferior vena cava (IVC) shunts, and to describe a treatment strategy for portosystemic encephalopathy, which can be caused by them.

MATERIALS AND METHODS

Between 2000 and 2004, we treated seven patients who had symptomatic IMV-IVC shunts. The results of imaging investigations, which included contrast-enhanced computed tomography (CT), angiography, and CT during arterial portography, were reviewed retrospectively. We also present our results in the four patients who were treated by retrograde transcaval obliteration (RTCO).

RESULTS

The IMV-IVC shunts had a tortuous or cirsoid appearance ranging in size from 7.2-14.6 mm. The shunts were located at a level near to the first branch of the inferior mesenteric artery. The four patients were successfully treated by RTCO and their clinical symptoms improved.

CONCLUSION

IMV-IVC shunts show a tortuous or cirsoid appearance, connecting at or near the first branch of the inferior mesenteric artery. For symptomatic IMV-IVC shunts, RTCO is recommended as the first choice treatment.

Para-cavernous sinus venous structures: anatomic variations and pathologic conditions evaluated on fat-suppressed 3D fast gradient-echo MR images

BACKGROUND

The cavernous sinus communicates with several para-cavernous sinus venous structures, receiving blood flow from the superficial middle cerebral vein (SMCV), the sphenoparietal sinus (SPS), and the superior ophthalmic vein, and draining into the superior and inferior petrosal sinuses and pterygoid and basilar plexuses. Anatomic variations of these veins have been previously reported; however, some details, such as the relationship between the SPS and the SMCV, are incompletely characterized. The anatomic variations of para-cavernous sinus veins, especially drainage patterns of the SMCV, were evaluated on MR imaging.

MATERIALS AND METHODS

Thirty-seven patients, including those without any lesions affecting the cavernous sinus or para-cavernous veins and patients with carotid cavernous fistulas, were examined by using fat-suppressed contrast-enhanced 3D fast gradient-echo MR imaging. Two neuroradiologists evaluated the images on a viewer, regarding the normal anatomy and the pathologic findings of the para-cavernous sinus veins.

RESULTS

The fat-suppressed 3D fast gradient-echo MR images clearly depicted the para-cavernous sinus venous structures in all patients. SMCVs had 4 variations in the drainage patterns. The most frequent pattern was drainage into the SPS (39%), and other types were draining into cavernous sinus, pterygoid plexus, and tentorial sinus. The SPS had 3 variations. The most frequent pattern was drainage into cavernous sinus (72%), and others were the hypoplastic type or those draining into pterygoid plexus.

CONCLUSION

The fat-suppressed 3D fast gradient-echo MR image is useful for evaluating the venous structures in the skull base. Knowledge of the variations is important for diagnosis and endovascular treatment of the cavernous sinus lesions.

Basal cell adenoma of the parotid gland: MR imaging findings with pathologic correlation

BACKGROUND AND PURPOSE

Basal cell adenomas (BCAs) are rare tumors of the parotid gland. Only a few case reports describing MR imaging features of BCA have been published. The aim of this study was to describe and characterize the MR findings of BCAs of the parotid gland.

MATERIALS AND METHODS

We retrospectively reviewed MR images of BCA with pathologic correlation in 8 cases (2 men and 6 women; age range, 52-82 years) collected between January 1992 and August 2004 from our pathologic data base. All MR images were retrospectively evaluated with respect to the marginal morphology, signal intensity (SI), and enhancement behavior by 2 experienced radiologists.

RESULTS

On pathologic examination, 5 tumors were solid type, 2 were trabecular type, and 1 was membranous type. All of the tumors were well circumscribed with smooth contours. Cystic changes were seen in 4 cases. On T1-weighted images (T1WI), 7 tumors showed homogeneously low SI equal to muscle and one showed heterogeneously low SI. On T2-weighted images (T2WI), all of them showed slightly lower SI than that of surrounding parotid tissue. On gadolinium-enhanced T1WI, 6 tumors demonstrated moderate enhancement and one demonstrated strong enhancement (membranous type). Dynamic studies were performed in 4 cases. All showed rapid and prolonged enhancement.

CONCLUSION

MR imaging findings of BCA were well-defined and smooth marginal morphologies, relatively low SI on both T11W and T2WI, and rapid and prolonged enhancement on dynamic study. Although BCAs are rare, they should be suspected when a tumor shows all of the characteristics noted here.

Warthin's tumor of parotid gland on Tc-99m pertechnetate scintigraphy with lemon juice stimulation: Tc-99m uptake, size, and pathologic correlation

The aim of this study was to evaluate the usefulness of technetium-99m (Tc-99m) pertechnetate scintigraphy with lemon juice stimulation in the diagnosis of Warthin's tumor and its correlation with Tc-99m uptake, tumor size, and histologic subtype. Tc-99m pertechnetate scintigraphy before and after lemon juice stimulation and pathologic specimens of 34 Warthin's tumors and 47 non-Warthin's lesions were retrospectively evaluated. Tc-99m uptake of Warthin's tumors before and after stimulation was visually graded as follows: absent; indeterminate; low grade; definite; and strong. Tumor size was defined as maximum diameter of the tumor measured from the surgical specimen. Warthin's tumors were classified into three histologic subtypes according to the ratio of epithelial and lymphoid stromal components: predominant epithelial; intermediate; and low-grade epithelial types. Eighteen of 34 (53%) Warthin's tumors and one benign lymphoepithelial cyst showed higher uptake than that of the normal parotid gland on Tc-99m scintigraphy before lemon juice stimulation. Thirty-two of the 34 (94%) Warthin's tumors, one benign lymphoepithelial cyst, one pleomorphic adenoma, and one oncocytoma revealed higher uptake than that of the normal parotid gland on Tc-99m scintigraphy after lemon juice stimulation. The mean size was 37 mm in strong uptake Warthin's tumors, 24 mm in definite uptake tumors, 19 mm in low-grade uptake tumors, and 12 mm in low-grade uptake tumors excluding those tumors with large cystic component. There was a significant correlation between tumor size and degree of Tc-99m uptake after lemon juice stimulation. However, there was no correlation between histologic subtype and Tc-99m uptake, and histologic subtype and tumor size in Warthin's tumors. Our study concludes that Tc-99m pertechnetate scintigraphy with lemon juice stimulation is useful for the detection and diagnosis of Warthin's tumor. The degree of uptake in Warthin's tumor on Tc-99m scintigraphy with lemon juice stimulation depends mainly on tumor size and the presence of large cystic component in it.

Root of the small-bowel mesentery: correlative anatomy and CT features of pathologic conditions

The root of the small-bowel mesentery (SBM) is an important peritoneal fold that is contiguous to other peritoneal ligaments and mesocolons. Several pathologic conditions can occur in the SBM itself, and diseases that spread through the connections from adjacent organs frequently involve it. The root of the SBM is contiguous to the hepatoduodenal ligament around the superior mesenteric vein (SMV) and contiguous to the right side of the transverse mesocolon around the gastrocolic trunk. The inferior mesenteric vein, which is a landmark of the descending mesocolon, runs along the left side of the root of the SBM. Malignant neoplasms can spread to the SBM by means of direct extension, extension along the neural plexus, extension along neighboring ligaments, or extension along lymphatic vessels. Inflammatory conditions such as pancreatitis and perforation of a jejunal diverticulum can also spread to the SBM. Anomalies that can occur in the SBM include rotation anomalies and internal hernia. Vascular lesions of the SBM include thrombosis of the superior mesenteric artery (SMA), acute SMV thrombosis, SMA dissection, arterioportal fistula, and portal venous gas. Other pathologic conditions that can occur in the SBM are edema or congestion, mesenteric tear, mesenteric panniculitis, and tumors or tumorlike lesions.

Ocular symptoms associated with a dural arteriovenous fistula involving the hypoglossal canal: selective transvenous coil embolization. Case report

The hypoglossal canals are an unusual location for dural arteriovenous fistulas (AVFs) to appear. One previous report of dural AVFs involving the hypoglossal canal has been published. In the present paper, the authors describe a dural AVF within the hypoglossal canal, which presented with ocular symptoms and was successfully treated by selective transvenous embolization. Magnetic resonance imaging and contralateral carotid arteriography were useful for determination of the exact location of the fistulous pouch, which was later packed with coils. Selective transvenous coil embolization with careful assessment of the location and pattern of the venous drainage of the dural AVF is a safe and effective treatment.

The local spread of lower bile duct cancer: evaluation by thin-section helical CT

This study illustrates the local spread of lower bile duct cancer with thin-section helical CT in correlation with the surgical and pathological findings. Pathologically, 16 patients had pancreatic invasion, 4 had small bowel mesentery invasion, 7 had extrapancreatic nerve plexus invasion, and 3 patients had vascular invasion. On thin-section helical CT, pancreatic invasion was correlated to the clarity or non-clarity of the bile duct mass-pancreas border and the presence of an intrapancreatic mass. Cases with small bowel mesentery and extrapancreatic nerve plexus invasion showed mass or stranding around the superior mesenteric artery and/or inferior pancreatoduodenal artery. Vascular invasion was seen as tumor contiguity to these vessels.

[Significance of CT findings and catecholamine determination in peripheral blood of asymptomatic pheochromocytoma and paraganglioma]

The purpose of this study was to assess the CT findings and significance of hormone determination in the peripheral blood of asymptomatic patients with pheochromocytoma and paraganglioma. CT findings in 29 patients with surgically proven pheochromocytoma(n = 19) and paraganglioma(n = 10) were reviewed. Nine patients(31%) were symptomatic and 20 (69%) were asymptomatic. Tumor size ranged from 39 mm to 114 mm(mean: 60 mm) in symptomatic patients and 11 mm to 100 mm(mean: 50 mm) in asymptomatic ones. Of the 9 symptomatic patients and 18 asymptomatic patients, a homogeneous solid pattern was seen in 4 and 4, mixed pattern in 2 and 6, and massive necrotic pattern in 3 and 8 patients, respectively, on CT scans. The CT attenuation values in symptomatic cases ranged from 30 HU to 50 HU(mean: 41 HU) on precontrast CT scans and 60 HU to 111 HU(mean: 77 HU) on postcontrast CT scans, while those in asymptomatic cases ranged from 15 HU to 48 HU(mean: 33 HU) on precontrast CT scans and 66 HU to 133 HU(mean: 95 HU) on postcontrast CT scans. There were no statistically significant differences in tumor size, homogeneity, or CT attenuation values between symptomatic and asymptomatic patients. All symptomatic patients and 17(89%) of 19 asymptomatic cases showed elevated levels of catecholamine (epinephrine) or norepinephrine in the peripheral blood. Our study showed that the CT findings in asymptomatic patients were similar to those in symptomatic patients, and 89% of asymptomatic patients showed elevation of catecholamine in the peripheral blood. Determination of catecholamine level in the peripheral blood is recommended for preoperative diagnosis in patients suspected of having asymptomatic pheochromocytoma or paraganglioma on CT scans.

Congenital extrahepatic portocaval shunt associated with hepatic hyperplastic nodules in a patient with Dubin-Johnson syndrome

We report a rare case of congenital extrahepatic portocaval shunt diagnosed during evaluation of hyperplastic nodules in the liver. Diagnostic imagings showed hypoplasia of the intrahepatic portal venous system and splanchnic portal venous return to the inferior vena cava through aberrant vessels. Altered hepatic blood flow dynamics due to this shunt may have been implicated in the etiology of the hepatic hyperplastic nodules.

Three-dimensional reconstructed images after rotational angiography in the evaluation of intracranial aneurysms: surgical correlation

OBJECTIVE

To evaluate the diagnostic accuracy of three-dimensional reconstructed images from rotational digital subtraction angiography in the surgical treatment of intracranial aneurysms.

METHODS

Twenty-two patients with 34 intracranial aneurysms underwent biplane angiography (40 degrees per s, 4.5 degrees per image, 8.8 frames per s). Three-dimensional (3-D) reconstructed images were obtained at a separate Advantage 3.1 workstation (General Electric, Milwaukee, WI) after the rotational images were transferred. The available visualization techniques included maximum intensity projection, shaded surface display, and virtual endoluminal view. All images were evaluated in correlation with intrasurgical visual data recorded on digital videotapes.

RESULTS

3-D reconstructed images correlated well with surgical findings. The shape of the aneurysms, their neck size, and their relationships to the parent vessels and other branches were depicted clearly, especially compared with images obtained by two-dimensional conventional digital subtraction angiography and magnetic resonance angiography.

CONCLUSION

3-D digital subtraction angiography enables the surgeon to understand the 3-D structure of lesions and is very useful in planning the surgical treatment of cerebral aneurysms.

CT assessment of the inferior peripancreatic veins: clinical significance

OBJECTIVE

The purpose of this study was to evaluate and clarify the clinical significance of CT scans of the inferior peripancreatic veins.

MATERIALS AND METHODS

Forty-three patients with suspected pancreatic disease underwent three-phase helical CT (collimation, 5 mm; reconstruction, 2.5 mm; scan delay, 30, 60, and 150 sec). The frequency of visualization on CT of the anterior and posterior inferior pancreaticoduodenal veins, inferior pancreaticoduodenal vein, and first jejunal trunk was assessed and correlated with angiographic and pathologic findings.

RESULTS

The frequency of visualization of normal inferior peripancreatic veins in patients (n = 22) with a normal portomesenteric vein was 36% for the anteroinferior pancreaticoduodenal vein, 36% for the posteroinferior pancreaticoduodenal vein, 59% for the inferior pancreaticoduodenal vein, and 100% for the first jejunal trunk. The smaller inferior peripancreatic veins were frequently not visualized when normal. In patients (n = 13) with pancreatic carcinoma involving the portosuperior mesenteric vein, all of the inferior peripancreatic veins were dilated and easily recognizable. When the tumor did not involve the portosuperior mesenteric vein but did involve the anteroinferior pancreaticoduodenal, posteroinferior pancreaticoduodenal, and inferior pancreaticoduodenal veins (n = 8), some of the other peripancreatic veins (first jejunal trunk, anterior and posterior superior pancreaticoduodenal veins, and gastrocolic trunk) were dilated. Dilatation indicated tumor extension to the third portion of the duodenum. In patients (n = 7) with involvement of the inferior pancreaticoduodenal vein, the first jejunal trunk, or both without the involvement of the portosuperior mesenteric vein, dilatation of the other peripancreatic veins (anteroinferior pancreaticoduodenal vein, posteroinferior pancreaticoduodenal vein, anterosuperior pancreaticoduodenal vein, posterosuperior pancreaticoduodenal vein, and gastrocolic trunk) indicated tumor invasion of only the second portion of the extrapancreatic nerve plexus (n = 4) and tumor invasion of both the second portion of the extrapancreatic nerve and the mesenteric root (n = 3).

CONCLUSION

Dilatation of peripancreatic veins with nonvisualization of inferior peripancreatic veins suggests tumor invasion of peripancreatic tissue.

Treatment of mandibular arteriovenous malformation by transvenous embolization: A case report

BACKGROUND

Arteriovenous malformations (AVMs) of the mandible are relatively rare and potentially life-threatening lesions. Treatment is usually difficult. This study presents a case with high-flow AVM of the mandible in which most of the AVM were occluded by transvenous coil embolization.

METHODS

Transvenous embolization using several size 57 microcoils and 3 Gianturco coils was performed through a right femoral vein access. The small residual AVM was occluded by superselective transarterial injection of cyanoacrylate.

RESULTS

Angiography after embolization showed almost complete obliteration of AVM. Panoramic radiograph 2 years after treatment confirmed reossification. There was no recurrence of the symptoms in a follow-up evaluation 2 years later.

CONCLUSION

Transvenous coil embolization may be a safer and more effective method in the treatment of mandibular AVM.

Septic thrombosis of the portal vein due to peripancreatic ligamental abscess

Septic thrombus formation of both the main portal vein and its intrahepatic branches were observed on CT in a patient with peripancreatic abscess. The septic thrombosis of portal vein (STPV) extended from the level of porta hepatis into the intrahepatic branches, but the portal vein and superior mesenteric vein at the level of pancreatic head were preserved with no evidence of thrombosis angiographically. The gas-containing abscess near the head of the pancreas extended toward the hepatic hilum and surrounded the portal vein and its branches on CT. It was concluded that these thrombi of portal vein branches at porta hepatis and intrahepatic branches were caused by extensions of peripancreatic abscess via the hepatoduodenal ligament and ligamentum teres. Computed tomography was useful in depicting the ligamentous spread of peripancreatic abscess resulting in STPV.

[Balloon-occluded retrograde transvenous obliteration (B-RTO) for gastric varices: therapeutic results and problems]

PURPOSE

To evaluate the usefulness of balloon-occluded retrograde transvenous obliteration (B-RTO) in the treatment of gastric varices.

MATERIALS AND METHODS

Twenty-one patients with ruptured or high-risk gastric varices underwent B-RTO. A 5-7F balloon catheter was advanced into the gastrorenal shunt and/or gastrophrenic shunt from the femoral vein. Five percent ethanolamine oleate iopamidol (EOI) was injected via the balloon catheter or a microcatheter that was advanced through the balloon catheter. EOI was withdrawn via the catheter after stagnation for 30-60 minutes. Contrast enhanced CT findings, endoscopic findings, and liver and renal function tests were evaluated before and after B-RTO.

RESULTS

Nineteen patients (90%) were successfully treated with B-RTO. In 17 of them, CT within two weeks after B-RTO showed complete thrombosis of the gastric varices, and the varices had disappeared or markedly regressed on endoscopy after 1-3 months. In the other two patients, in whom CT showed partial thrombosis of the varices, the varices regressed minimally. Liver and renal function tests did not show significant changes in 17 of 19 patients (89%). Transient worsening of liver function was seen in one patient in whom a small amount of EOI moved into the splenic vein during balloon occlusion. Acute renal failure occurred in the other patient with the use of 50 ml of EOI.

CONCLUSION

B-RTO is an effective therapy for gastric varices. However, careful attention should be paid to the amount of EOI and hemodynamic change caused by shunt occlusion.

[Evaluation of 99mTc-DTPA-HSA abdominal imaging of protein-losing gastroenteropathy]

Abdominal images were obtained after the intravenous injection of 99mTc-HSA-D in 8 patients with protein-losing gastroenteropathy (PLG). Six neck images and 7 abdominal images were obtained in 11 patients with ischemic heart disease as a control study. We evaluated all the images with respect to visualization, initial appearance time, and movement of abnormal radioactivity. In 7 of 8 patients with PLG, abnormal radioactivity in the intestine appeared from 10 min to 4 hours after injection, and moved 6 hours after injection. In 6 of 7 abdominal images of control cases, slight activity was observed in the alimentary tract 6 hours or 24 hours after injection. The thyroid was not visualized in any of the 6 cases. In conclusion, if radioactivity in the alimentary tract was first observed 6 hours or later after injection, the diagnosis of PLG may be difficult by this method alone. It still may be necessary to perform the alpha 1-antitrypsin test for the correct diagnosis of PLG.

Effects of portal-systemic shunt embolization on the basal ganglia: MRI

We report MRI in a patient with portal-systemic encephalopathy, in which the high signal in the basal ganglia on T1-weighted images showed marked resolution after successful embolization of the intrahepatic portal-systemic venous shunt.

[In vivo evaluation of the new antithrombogenic reservoir-catheter coated with polymer blend copolymer]

We evaluated the antithrombogenicity of 4F-catheters coated with the new antithrombogenic material fluorine-acryl- styrene-urethane-silicone (FASUS) graft-block copolymer by dissecting microscopic and scanning electron microscopic observations. These catheters were temporarily used for the infusa-A-port, which was prepared for the treatment of four patients with bladder cancer. Two heparin-coated catheters were also evaluated. All FASUS-coated catheters contained thrombi consisting of red thrombi and/or fibrin thrombi. Massive red thrombus was seen at the site of curvature of the catheters, 1 cm distal to the tip of the catheter. However, the portion 20 cm distal to the tip of the catheter had no red thrombus, but contained minimal fibrin thrombus or plasma protein. The heparin-coated catheters showed the same findings as the FASUS catheters. The FASUS-coated catheters were not superior in antithrombogenicity to the heparin-coated catheters. It was concluded that the FASUS-coated catheters used in this study seemed to have problems in regard to their preshaped curvature and the material used in catheter. These aspects need to be improved.

[Standardization of use of 4-F size catheter for selective transcatheter angiography and intervention of abdomen]

To evaluate the safety and efficacy of a new 4 French (F) catheter/sheath system with large lumina for selective abdominal arteriography and intervention, the usefulness of the 4F sheath (4F group, 88 patients) was compared with that of a 5.5F sheath and a 7F sheath (5.5F group, 7F group, 156 patients). The compression time of the arterial puncture site and the ambulation time in the 4F group were significantly shorter than those in the 5.5F and 7F groups. The hemorrhagic complication rate in the 4F group (15%) was less than those in the 5.5F group (23%) and 7F group (27%). The severity of hemorrhagic complications in the 4F group (hematoma 2.3%, woozing 14%, and rhexis 0%) was significantly less than in the 5F group (3%, 21%, 0%) and 7F group (11%, 19%, 2.4%). The controlability of the 4F catheter as compared with a 5F catheter was estimated in 35 patients by questionnaire. The torque transmissibility and the endurability of the kink of the 4F catheter were poor in comparison with the 5F catheter. However, with respect to the ability to follow over a guidewire, the 4F catheter showed great advantage over the 5F catheter. It is concluded that the 4F catheter/sheath system is feasible for general use in selective abdominal arteriography and interventions.

[An afterloading procedure using 137Cs needle for tongue carcinoma]

We have developed an afterloading procedure using Cs needle for tongue carcinoma. Seven patients with T1-2NO squamous cell carcinoma of the oral tongue were treated by this method at the Oita Medical University between 1988 and 1994. This method reduced the radiotherapist's radiation exposure and resulted in good local control in the primary site. We have found no other report of a case treated in this way. We emphasize that cesium therapy using an afterloading procedure is very useful in treating tongue carcinoma.

[Clinical significance of lymphadenopathy in the upper abdomen; ultrasound demonstration]

Little attention has been paid to the ultrasound differentiation of benign abdominal lymphadenopathy from the malignant type. We reviewed 133 ultrasound examinations of 116 patients with lymphadenopathy seen over the upper abdomen and high retroperitoneum to clarify the differences in ultrasound findings of enlarged lymph nodes caused by benign and malignant abdominal diseases. The location, number, internal texture, size, length/thickness ratio of the lymph nodes, and relation with hepatitis virus infection were evaluated. Among 75 patients with benign diseases, 63 patients showed liver dysfunction and 42/65 (65%) showed positive hepatitis C virus antibody (HCV-Ab). Enlarged lymph nodes were seen over the common hepatic artery or hepatoduodenal ligament in 84%. Most patients had fewer than 4 enlarged nodes, and 46 patients had a single enlarged node. The length/thickness ratio of nodules was more than 2.5 in 63%. In 41 patients with malignant diseases, enlarged lymph nodes tended to be more widespread in location, larger in number, and smaller in length/thickness ratio than those of benign diseases. Lymphadenopathy over the common hepatic artery or hepatoduodenal ligament may suggest the presence of chronic active hepatitis, especially relating to HCV infection, even though hepatic sonotexture is normal on ultrasound examination.

MRI of cervical masses of thymic origin

OBJECTIVE

Thymic diseases can arise from remnants of thymic tissues along the path of fetal descent and may simulate thyroid tumors or lymphadenopathy.

MATERIALS AND METHODS

We present two patients with a cervical mass arising from the cervical thymus that was caused by incomplete descent of the thymus into the mediastinum.

RESULTS

In one patient a cervical mass was surgically confirmed to be a cervical thymoma, which simulated a thyroid cancer on CT and 201Tl-scintigraphy. In another patient, cervical thymic hyperplasia arising from an incompletely descended thymus was surgically confirmed. The isointensity between the cervical mass and an enlarged mediastinal thymus was recognized on MRI.

CONCLUSION

If a cervical mass is located in the region of the lower pole of the thyroid or if there is a connection or the same intensity between the cervical mass and the mediastinal thymus on MRI, a diagnosis of a cervical mass of thymic origin should be considered.

[Unsuspected painless subacute thyroiditis detected by radiogallium scintigraphy]

Two cases of painless subacute thyroiditis were presented in whom fever, fatigue and arthralgia except for thyroidal pain and swelling were complained. Until a intense uptake of the thyroid was found on radiogallium scintigraphy, the examinations of the thyroid had not been done. Laboratory data showed increased erythrocyte sedimentation rate, C-reactive protein and serum alkaline phosphatase, and mild leukocytosis. Skeletal, hepatic and biliary diseases were denied. In patients who have fever, increased erythrocyte sedimentation rate and serum alkaline phosphatase elevation without apparent sources, thyroid function should be evaluated because subacute thyroiditis can be associated with elevation of the serum alkaline phosphatase.