Dissection of the V4 segment of the vertebral artery: clinicoradiologic manifestations and endovascular treatment.

Intracranial vertebral artery (VA) dissection has three clinical presentations: ischemia, hemorrhage, and mass effect. Imaging findings of intracranial VA dissections vary according to clinical presentation. Irregular stenosis or occlusion of the VA is the most common finding in patients with posterior fossa infarction, whereas a dissecting aneurysm is the main feature in those with acute subarachnoid hemorrhage. A chronic, giant, dissecting aneurysm can cause mass effect on the brain stem or cranial nerves, as well as distal embolism. Magnetic resonance imaging is useful for detection of intramural hematomas and intimal flaps, both of which are diagnostic of VA dissection. Multidetector computed tomography angiography is increasingly used for diagnosis of VA dissection. Catheter angiography is still beneficial for evaluation of precise endoluminal morphology of the dissection before surgical or endovascular intervention. Endovascular treatment is now considered a major therapeutic option for patients with a ruptured dissecting aneurysm or a chronic dissecting aneurysm. Anticoagulation therapy is currently considered the initial treatment of choice in patients with posterior circulation ischemic symptoms. Endovascular treatment, such as stent-assisted angioplasty or coil occlusion at the dissection site, can be performed in selected patients with posterior fossa ischemic symptoms.

Symptomatic middle cerebral artery stenosis treated with intracranial angioplasty: experience in 32 patients.

PURPOSE: To retrospectively review the outcome after angioplasty in patients with symptomatic, high-grade middle cerebral artery (MCA) stenosis refractory to medical therapy. MATERIALS AND METHODS: Institutional review board approval to perform angioplasty procedures for MCA stenosis was obtained, and written informed consent was obtained from each patient or the patient's family. Institutional review board approval was also obtained for the retrospective review of patients' data. The institutional review board waived the need for informed consent for this retrospective analysis.Thirty-two consecutive patients (18 men, 14 women; median age, 55 years) with symptomatic MCA stenosis greater than 70% underwent angioplasty between June 1994 and July 2003. The indication for angioplasty was recurrent transient ischemic attack (TIA) refractory to antithrombotic therapy in 24 patients and acute ischemic stroke in eight. Patient records were retrospectively reviewed for angiographic findings, periprocedural complications, and follow-up data. RESULTS: Angioplasty reduced the degree of stenosis to less than 50% in 29 of 32 patients (91%). There were two major complications during angioplasty: acute occlusion of the treated MCA and vascular rupture that resulted in death. Thus, the risk of disabling stroke or death was 6% (two of 32 patients), and the mortality rate was 3% (one of 32 patients). The rate of periprocedural TIA was 19% (six of 32 patients). Five patients had asymptomatic intimal dissection. During the follow-up period, which ranged from 5 to 92 months (median, 20 months), TIA occurred in one patient in whom the results of angioplasty were suboptimal. The remaining 29 patients did not experience further ischemic events attributable to the treated MCA stenosis during the follow-up period. Asymptomatic restenosis occurred in one of five patients in whom data from follow-up angiography were available. CONCLUSION: MCA angioplasty resulted in a low recurrence rate of ischemic symptoms during long-term follow-up.

MR imaging of solitary fibrous tumors in the head and neck.

OBJECTIVE: Solitary fibrous tumor (SFT) is a very rare tumor. The purpose of this study is to determine the MR imaging features of SFT in the intracranial and extracranial head and neck regions. MATERIALS AND METHODS: We retrospectively reviewed six MR images and two CT images of six histologically proven cases of SFT that occurred in four men and two women, and their ages ranged from 46 to 59 years. These imaging findings were correlated with the microscopic findings of their surgical specimens. RESULTS: Six SFTs arose in the meninges (the petrous ridge and the pituitary fossa), the parotid gland, the parapharyngeal space, the buccal space and the maxillary sinus. On the MR images, SFTs in the intracranial and extracranial head and neck regions were mostly isointense to the muscle on the T1-weighted images, they were hyperintense on the T2-weighted images and they all had intense enhancement. On the T1- and T2-weighted images, hypointense lines were observed within in five SFTs. On the CT images, the SFTs were hypodense to the muscle on the unenhanced images and they were heterogeneously enhanced on the contrast-enhanced images. An exceptional case of pituitary SFT was hypointense on the T2-weighted images and it was hyperdense on the unenhanced CT images, which correlated with the increased collagenous component and the cellular compactness. CONCLUSION: The imaging features of SFT are nonspecific; however, SFT should be included in the differential diagnosis of masses involving the intracranial and extracranial head and neck regions.

Preoperative evaluation of venous systems with 3-dimensional contrast-enhanced magnetic resonance venography in brain tumors: comparison with time-of-flight magnetic resonance venography and digital subtraction angiography.

BACKGROUND: Recent developments in magnetic resonance (MR) technology now enable the use of MR venography, providing 3-dimensional (3D) images of intracranial venous structures. The purpose of this study was to assess the usefulness of 3D contrast-enhanced MR venography (CE MRV) in the evaluation of intracranial venous system for surgical planning of brain tumors. METHODS: Forty patients underwent 3D CE MRV, as well as 25 patients, 2-dimensional (2D) time-of-flight (TOF) MR venography in axial and sagittal planes; and 10 patients, digital subtraction angiography. We determined the number of visualized sinuses and cortical veins. Degree of visualization of the intracranial venous system on 3D CE MRV was compared with that of 2D TOF MR venography and digital subtraction angiography as a standard. We also assessed the value of 3D CE MRV in the investigation of sinus occlusion or localization of cortical draining veins preoperatively. RESULTS: Superficial cortical veins and the dural sinus were better visualized on 3D CE MRV than on 2D TOF MR venography. Both MR venographic techniques visualized superior sagittal sinus, lateral sinus, sigmoid sinus, straight sinus, and internal cerebral vein and provided more detailed information by showing obstructed sinuses in brain tumors. Only 3D CE MRV showed superficial cortical draining veins. However, it was difficult to accurately evaluate the presence of cortical collateral venous drainage. CONCLUSION: Although we do not yet advocate MR venography to replace conventional angiography as the imaging standard for brain tumors, 3D CE MRV can be regarded as a valuable diagnostic method just in evaluating the status of major sinuses and localization of the cortical draining veins.

Bilateral paramedian thalamic contrast enhancement on CT after Intra-arterial thrombolysis.

A 58-year-old woman presented with an acute embolic occlusion of the distal basilar artery. She underwent angioplasty and intra-arterial thrombolysis. Angiography performed after recanalization revealed a single perforating thalamic artery. A nonenhanced CT scan carried out immediately after the procedure revealed hyperdense lesions in the bilateral paramedian portions of the thalami, which disappeared on the 24-hour follow-up CT scan. Three months later, the patient improved to functional independence, but had some memory dysfunction and vertical gaze palsy. This case suggests that contrast enhancement or extravasation can occur in the thalamus after intra-arterial thrombolysis performed to recanalize a basilar artery occlusion.

CT in blunt liver trauma.

Nonsurgical treatment has become the standard of care in hemodynamically stable patients with blunt liver trauma. The use of helical computed tomography (CT) in the diagnosis and management of blunt liver trauma is mainly responsible for the notable shift during the past decade from routine surgical to nonsurgical management of blunt liver injuries. CT is the diagnostic modality of choice for the evaluation of blunt liver trauma in hemodynamically stable patients and can accurately help identify hepatic parenchymal injuries, help quantify the degree of hemoperitoneum, and reveal associated injuries in other abdominal organs, retroperitoneal structures, and the gastrointestinal tract. The CT features of blunt liver trauma include lacerations, subcapsular or parenchymal hematomas, active hemorrhage, juxtahepatic venous injuries, periportal low attenuation, and a flat inferior vena cava. It is important that radiologists be familiar with the liver injury grading system based on these CT features that was established by the American Association for the Surgery of Trauma. CT is also useful in the assessment of delayed complications in blunt liver trauma, including delayed hemorrhage, hepatic or perihepatic abscess, posttraumatic pseudoaneurysm and hemobilia, and biliary complications such as biloma and bile peritonitis. Follow-up CT is needed in patients with high-grade liver injuries to identify potential complications that require early intervention.

Assessment of cerebrocortical regions associated with sexual arousal in premenopausal and menopausal women by using BOLD-based functional MRI.

PURPOSE: The aim of this study was to compare the cerebral regions associated with sexual arousal between premenopausal and menopausal women by using functional magnetic resonance imaging (f MRI). MATERIALS AND METHODS: Ten premenopausal and 10 menopausal women underwent fMRI on a 1.5T MR scanner using the blood oxygen level dependent technique. To identify the activated brain regions associated with sexual response, brain activation was assessed during 1 minute of a nonerotic film, followed by 4 minutes of an erotic film. RESULTS: The overall activation ratios of the premenopausal women were greater than those of the menopausal women by approximately 8% on average. The limbic, temporal association areas, and parietal lobe showed greater enhancement of signal intensities in premenopausal women. However, signal enhancement in the genu of the corpus callosum and superior frontal gyrus was dominant in menopausal women. CONCLUSIONS: The activated brain center associated with visually evoked sexual arousal showed qualitative and quantitative differences between premenopausal and menopausal women.

Pelvic arterial hemorrhage in patients with pelvic fractures: detection with contrast-enhanced CT.

Arterial hemorrhage is one of the most serious problems associated with pelvic fractures, and it remains the leading cause of death attributable to pelvic fracture. At many trauma centers, contrast material-enhanced computed tomography (CT) is increasingly used for initial diagnosis in the evaluation of patients with pelvic fractures. Extravasation of contrast material in the pelvis at contrast-enhanced CT is an accurate indicator of ongoing arterial hemorrhage in patients with pelvic fractures. Detection of such extravasation on CT scans can lead to prompt performance of angiographic embolization, which can be lifesaving. Furthermore, the site of contrast material extravasation seen at CT corresponds well to the site of bleeding seen at angiography. This correspondence enables the interventional radiologist to selectively study the arteries most likely to be injured and therefore potentially reduce the patient's morbidity and mortality. Knowledge of the relevant pelvic anatomy, including the osseous, ligamentous, and especially axial vascular anatomy, is essential for understanding the relationship between a site of contrast material extravasation at CT and the specific injured artery visualized at angiography.

Contrast enhancement and contrast extravasation on computed tomography after intra-arterial thrombolysis in patients with acute ischemic stroke.

BACKGROUND AND PURPOSE: The goal of this study was to determine the CT findings and clinical consequences of contrast enhancement and contrast extravasation on CT scans obtained after intra-arterial thrombolytic therapy for treatment of acute ischemic stroke. METHODS: Sixty-two patients were treated with intra-arterial thrombolysis. All patients underwent nonenhanced CT scans immediately and 24 hours after thrombolytic therapy. Contrast enhancement was defined as a hyperdense lesion that disappeared on a 24-hour follow-up CT scan. Contrast extravasation was defined as a hyperdense lesion with maximum Hounsfield unit >90 that persisted on a follow-up CT scan. We evaluated the differences in the clinical and radiological data between 3 groups: contrast enhancement, contrast extravasation, and control groups. RESULTS: Contrast enhancement was found in 14 of 62 patients (22.6%); contrast extravasation was seen in 7 (11.3%). Compared with the control group, the contrast enhancement group had a lower recanalization grade (64.3% versus 34.1%, P=0.048) and a lower incidence of hemorrhagic transformation (14.3% versus 43.9%, P=0.047). The contrast extravasation group had a higher incidence of both hemorrhage (100% versus 43.9%, P=0.006) and symptomatic hemorrhage (100% versus 14.6%, P<0.001) than the control group. Poor outcomes were more frequent in the contrast extravasation group (100% versus 38.9%, P=0.003) than the control group. CONCLUSIONS: Contrast enhancement on CT scans obtained after intra-arterial thrombolysis is usually not associated with hemorrhagic complications. However, contrast extravasation is highly associated with parenchymatous hematoma and should be considered a negative prognostic sign.

Uterine cervical carcinoma after therapy: CT and MR imaging findings.

Cervical carcinoma is one of the most frequent causes of death in women. Computed tomography (CT) and magnetic resonance (MR) imaging are the primary modalities for follow-up of treated cervical carcinoma. A normal vaginal cuff after hysterectomy appears as a smooth, low-signal-intensity muscular wall on T2-weighted MR images. Early (2-3 months after treatment) and significant decreases in the signal intensity and volume of the tumor at MR imaging indicate a good response to radiation therapy. Sites of recurrence are the pelvis, lymph nodes, and distant sites. Pelvic recurrence appears as a heterogeneously enhancing mass at contrast material-enhanced CT and often appears as a heterogeneous, high-signal-intensity mass at T2-weighted MR imaging. Lymph node recurrence ranges from scattered, minimally enlarged nodes to large, conglomerate nodal masses. Determination of neoplastic infiltration of lymph nodes is based on size; most researchers consider nodes greater than 1 cm in short-axis diameter to be metastatic. Distant metastases are usually due to recurrent disease and occur in the abdomen, thorax, and bone. Knowledge of the normal therapeutic changes and the spectrum of recurrent tumor in patients with cervical carcinoma is important for accurate interpretation of follow-up CT and MR images.

Prognostication of recovery in patients with acute ischemic stroke through the use of brain SPECT with Technetium-99m--labeled metronidazole.

BACKGROUND AND PURPOSE: We hypothesized that technetium-99m-ethylene dicysteine-metronidazole (99mTc-EC-MN) localizes to brain tissue that is hypoxic but viable. This study prospectively evaluated the relationship between neurological outcome and uptake of 99mTc-EC-MN in peri-infarcted regions of the brain. METHODS: Eight patients with acute ischemic stroke in the territory of the left middle cerebral artery underwent 99mTc-EC-MN and 99mTc-ethyl cysteinate dimer (ECD) brain SPECTs on the same day during the subacute stage (10.3+/-2.5 days). The infarct volumes from 99mTc-ECD images (IV(ECD)), infarct volumes from diffusion-weighted MRI images (IV(DW)), and hypoxic volume (HV) from 99mTc-EC-MN images were calculated. The net infarct volume (NIV(ECD)) was defined as IV(ECD) minus HV. The National Institutes of Health Stroke Scale scores were measured on admission and days 1, 3, 7, and 30. RESULTS: IV(ECD) was greater than IV(DW). The lesion-to-normal count-density ratios of 99mTc-EC-MN ranged from 1.80 to 5.96. HV was 60.2+/-65.2 cm3, and the mean percent HV was 24.5+/-28.1% of IV(ECD). NIV(ECD) was 162.6+/-133.4 cm3 and was significantly smaller than IV(ECD). NIV(ECD) was significantly correlated with National Institutes of Health Stroke Scale score at 1 month and was a significant predictor of neurological deficit at 1 month. CONCLUSIONS: 99mTc-EC-MN brain SPECT can detect hypoxic tissue after acute ischemic stroke and, in combination with 99mTc-ECD brain SPECT, is useful in predicting neurological outcome in ischemic stroke patients.

Three-dimensional multi-detector row CT portal venography in the evaluation of portosystemic collateral vessels in liver cirrhosis.

Multi-detector row computed tomography (CT) offers distinct advantages over traditional spiral CT. Multi-detector row CT scanners are faster and allow thinner collimation than single-detector row spiral CT scanners. The use of multi-detector row CT combined with postprocessing of the imaging data with a variety of three-dimensional reformatting techniques (eg, maximum intensity projection, shaded surface display, volume rendering) allows creation of vascular maps whose quality equals or exceeds that of maps created at classic angiography for many applications. Three-dimensional multi-detector row CT portal venography can help determine the extent and location of portosystemic collateral vessels (eg, left gastric vein, short gastric vein, esophageal and paraesophageal varices, splenorenal and gastrorenal shunts, paraumbilical and abdominal wall veins) in patients with liver cirrhosis and is probably the optimal imaging technique in this setting.

Neovascular glaucoma associated with cilioretinal artery occlusion combined with perfused central retinal vein occlusion.

BACKGROUND: Cilioretinal artery occlusion rarely results in neovascular glaucoma, especially in cases of extensive cilioretinal infarction and combined retinal vascular occlusion. CASE: A 62-year-old man with diabetes mellitus and essential hypertension showed a visual acuity of counting fingers, retinal whitening temporal to the optic disc with mild dilation and tortuosity of the retinal veins, and retinal hemorrhages in four quadrants of his right eye. Fluorescein angiography demonstrated a delayed filling of the central retinal vein and cilioretinal artery. OBSERVATIONS: Two months later, neovascular glaucoma developed and retinal ablation was performed using an argon laser. Trabeculectomy was also performed due to the intractability of the glaucoma, and central artery occlusion was found. On magnetic resonance angiography, the right distal common carotid artery was irregularly narrowed and the right ophthalmic artery was almost entirely occluded. CONCLUSIONS: In cases of cilioretinal artery occlusion and perfused central retinal vein occlusion with multiple risk factors, close follow-up is advised.

Luteinized fat in Krukenberg tumor: MR findings.

To our knowledge, there is no description of the fat-containing Krukenberg tumor. We report on a case of Krukenberg tumor associated with luteinized fat, which showed hyperintensity on T1-weighted MR image. The diagnosis was surgically confirmed. Hyperintense portion of the Krukenberg tumor on T1-weighted image showed diminished signal intensity on fat-saturated, T1-weighted images. Krukenberg tumor should be considered in the differential diagnosis of ovarian masses when fat signal is seen.