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.

Termination of the vertebral veins: Evaluation by multidetector row computed tomography.

The purpose of this study was to evaluate the topographic anatomy of the vertebral vein (VV) in the lower neck and thoracic inlet using CT scans. Enhanced CT scans using 32-MDCT were obtained for 199 consecutive patients. Reconstructed images with 1-mm section thickness/intervals were evaluated by two radiologists examining the drainage point, number, and route of VVs using frame forwarding and the rewind function on the DICOM viewer. The VV was classified into four types as follows: Type A (80.6%), a VV that descended ventral to the subclavian artery (SA) and drained into the upper portion of the brachiocephalic vein (BCV); Type B (5.8%), a VV that descended dorsal to the SA and drained into the upper portion or the lower portion of the BCV; Type C (8.3%), a doubled VVs that crossed both sides of the SA and drained into the upper portion of the BCV and formed a common trunk; Type D (5.3%), a VV ventral to the SA that drained into the upper portion of the BCV and another VV dorsal to the SA drained into the upper portion or the lower portion of the BCV. Some variations were observed in regard to the drainage point, number, and route of the VVs. Classification of the VV may be useful for interpreting chest CT scans and in better understanding the embryologic development of the vertebral vein.

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.

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.

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.

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.

[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.

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.

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.

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.