Effect of breed as a risk factor for humeral condylar fracture in skeletally immature dogs.

OBJECTIVES: To investigate the effect of breed as a risk factor associated with humeral condylar fracture in skeletally immature dogs in the UK. MATERIALS AND METHODS: Retrospective study of dogs under 12 months of age that were presented with humeral condylar fracture to three specialist referral centres between 2015 and 2018. Data retrieved from medical records included breed, age, gender, neuter status, affected limb, fracture configuration and aetiology of the fracture. Breed population percentages were compared with those recorded by the UK Kennel Club. RESULTS: Of the 115 dogs with 118 fractures, French bulldogs (41%) and English springer spaniels (15%) were overrepresented: humeral condylar fractures were more commonly diagnosed in French bulldogs (odds ratio = 5.86) and English springer spaniels (odds ratio = 5.66) compared with mixed-breed dogs. Lateral condylar fractures occurred in 70% of cases, with medial condylar fractures and Y/T fractures accounting for 9% and 21%, respectively. Median age at the time of fracture was 4 months (range 2 to 10 months). CLINICAL SIGNIFICANCE: French bulldogs and English springer spaniels were identified as being at potentially increased risk of humeral condylar fracture in skeletally immature dogs.

MR imaging of papillary tumor of the pineal region.

We report the imaging features of 4 cases of patients with papillary tumor of the pineal region, a tumor newly recognized in the 2007 World Health Organization "Classification of Tumors of the Nervous System." In each case, the tumor was intrinsically hyperintense on T1-weighted images with a characteristic location in the posterior commissure or pineal region. The pathologic hallmarks of the tumor are discussed, including a possible explanation for the MR imaging characteristics in our cases.

Cerebral venous thrombosis: combined intrathrombus rtPA and intravenous heparin.

BACKGROUND AND PURPOSE: We chose to evaluate the safety and efficacy of combined intrathrombus rtPA and intravenous heparin in cerebral venous thrombosis (CVT). METHODS: We treated 12 patients with symptoms of 1 to 40 days' duration (eg, headache, somnolence, focal deficits, seizures, and nausea and vomiting). Pretreatment MRI disclosed subtle hemorrhagic venous infarction in 4 patients, obvious hemorrhagic infarction in 2, small parenchymal hemorrhage from recent pallidotomy in 1, and no focal lesion in 5. Magnetic resonance venography and contrast venography identified thrombi in the superior sagittal sinus (SSS) in 3 patients; transverse/sigmoid sinus (TS/SS) in 2; SSS and both TS/SS in 1; SSS and 1 TS/SS in 5; and SSS, 1 TS/SS, and straight sinus in 1 patient. A loading dose of rtPA was instilled throughout the clot at 1 mg/cm, followed by continuous intrathrombus infusion at 1 to 2 mg/h. Intravenous heparin was infused concomitantly. RESULTS: Flow was restored completely in 6 patients and partially in 3, with a mean rtPA dose of 46 mg (range, 23 to 128 mg) at a mean time of 29 hours (range, 13 to 77 hours). Symptoms improved in these 9 patients concomitantly with flow restoration. Flow could not be restored in 3 patients. In 1 of them, treatment was stopped when little progress had been made, and fibrinogen level dropped to 118 mg/dL. In the other 2 patients, hemorrhagic worsening occurred, and treatment was abbreviated after initial rtPA dosing. In 1 of these, the hematoma was evacuated. CONCLUSIONS: Our experience with intrathrombus rtPA in conjunction with intravenous heparin in patients with CVT is encouraging. This therapy should probably be regarded as unsafe in patients with obvious hemorrhage. Time to restore flow may be faster than with urokinase (an average of 71 hours has been reported for 29 documented patients). Further evaluation of rtPA with heparin in CVT is warranted.

Imaging of carotid artery disease. Conventional angiography.

Conventional angiography has lost its preeminence as a screening tool for extracranial carotid artery disease. Similarly, conventional angiography may be at the crossroads for its use as a presurgical planning study for carotid endarterectomy. This article discusses angiographic techniques and atherosclerotic carotid artery disease involving the carotid bifurcation. Special emphasis is placed in discussing the role of angiography in the recent large prospective trials evaluating endarterectomy for carotid artery disease.

Comparison of centralized versus "site-based" measurement of angiographic stenosis for eligibility in the asymptomatic carotid atherosclerosis study.

RATIONALE AND OBJECTIVES: The authors determine the reliability of centralized versus noncentralized (site-based) measurement of angiographic stenosis of patients enrolled into the multicenter, prospective, Asymptomatic Carotid Atherosclerosis Study by angiographic studies. METHODS: Percent agreements and correlations of 244 masked and prospectively interpreted angiograms were calculated for comparison of centralized and noncentralized readers measuring the percent carotid stenosis from the same angiographic studies. Univariate summary statistics for differences in percent stenoses were calculated for these readings. RESULTS: Agreement between readings were 88.5% and 91.8% with kappa statistics of 0.77 and 0.73 for > or = 60% and > or = 80% stenosis, respectively, for comparison of 33 centers to the designated central reader. Comparison between the designated central reader and a second central reader derived percent agreements of 85.0% and 86.5% with kappa statistics of 0.69 and 0.41 for > or = 60% and > or = 80% stenoses, respectively, for arteries selected from the original group. Hence, agreement was slightly better between the enrolling centers and the designated central reader than between the two central readers. CONCLUSIONS: Both centralized and noncentralized (site-based) methods of angiographic measurement of stenosis are equally reliable for large, prospective, masked, multicenter trials when quality control measures are instituted to ensure uniform application of eligibility criteria.

Posttraumatic epistaxis from injury to the pterygovaginal artery.

Facial and skull base trauma can cause clinically significant epistaxis. Optimal evaluation and treatment require knowledge of the pertinent vascular and skull base anatomy. We describe a patient with extensive skull base injury and epistaxis in whom CT revealed a fracture through the roof of the nasopharynx and arteriography showed injury to the pterygovaginal (pharyngeal) artery. The fracture was successfully treated with transarterial particulate embolization.

Preliminary results of intracranial angioplasty for vascular stenosis caused by atherosclerosis and vasculitis.

PURPOSE: To evaluate the results of balloon angioplasty of 17 stenoses resulting from intracranial atherosclerosis and vasculitis. METHODS: Seventeen skull-base and intracranial lesions were dilated with a microballoon angioplasty catheter. RESULTS: Initially, 16 of the 17 stenoses showed improvement at angiography. Moderate residual stenosis was found in 2 of 12 atherosclerotic lesions, both in the distal vertebral artery. Angioplasty in 1 of 12 atherosclerotic lesions caused worsening of the stenotic site, also in the distal V4 region of the vertebral artery. All but one of the patients improved clinically. However, all five lesions caused by acute vasculitis progressed to occlusion after initial improvement. CONCLUSION: Intracranial percutaneous transluminal angioplasty is a viable nonsurgical option for the treatment of atherosclerotic vascular insufficiency, but it may not be as successful in treating lesions caused by vasculitis in the acute phase.

Trigeminal-cavernous fistula: Saltzman anatomy revisited.

We report a case of a carotid-cavernous fistula through a persistent trigeminal artery with endovascular treatment, and discuss the Saltzman classification of persistent trigeminal artery anatomy and its importance in treatment of this lesion.

Unusual pattern of a deep developmental venous anomaly on CT and MR studies.

OBJECTIVE: This article focuses on an unusual cross-sectional imaging pattern of a deep developmental venous anomaly (DVA). Since these anomalies are nonpathologic, they must not be interpreted as a disease that requires further costly workup and potentially injurious procedures (cerebral angiography). MATERIALS AND METHODS: Two women aged 19 (Case 1) and 30 (Case 2) years sought medical evaluation for severe headaches. Both patients underwent CT, MRI, and conventional cerebral angiography. Case 1 also underwent MR venography. RESULTS: The diagnosis of an unusual DVA in Case 1 was confirmed only after conventional catheter angiography and a follow-up MR venogram. In Case 2 the diagnosis was inferred based upon the CT, MRI, and conventional angiography results and the marked similarity to Case 1. The presumptive diagnosis in Case 2 would not have been made with confidence without the prior experience of managing Case 1. CONCLUSION: DVAs (venous angiomas) are extreme variations in the pattern of intracranial venous drainage. These two case reports highlight an unusual pattern of this benign entity. Individuals interpreting cross-sectional imaging studies should be cognizant of this pattern.

The safety and effectiveness of brain arteriovenous malformation embolization using acrylic and particles: the experiences of a single institution.

The purpose of this article is to report on the safety and effectiveness of brain arteriovenous malformation (AVM) embolization for two series of patients, of which one was treated with particulate embolization and the other with acrylic embolization. Sixty-five consecutive patients from embolization logs and patient records from 1988 to 1993 were reviewed. AVMs were routinely treated with particulate embolization early in the review (1988-1991), and after a transition period, the technique was changed to acrylic embolization for the remainder of the study period (1992-1993). All patients were treated with the ultimate goal of complete AVM obliteration. AVMs were embolized and resected, if possible, and if unresectable, they were reduced in size with embolization and radiated. The course of treatment for each patient was reviewed. The effectiveness at the end of treatment was analyzed for the ability to resect the AVM and, if unresectable, the ability to reduce the AVM to radiation size. Additionally, the safety of each embolization technique was evaluated in the context of comprehensive care, in terms of the safety of the procedure itself, the surgical resection after embolization, and the outcome at the end of comprehensive treatment. This article outlines the safety and effectiveness of acrylic and particulate embolization at a single institution. The ability to surgically resect an AVM after embolization and to reduce nidus size with acrylic was at least comparable with that with particulate embolization. Comprehensive complication rates were lower after acrylic embolization and were heavily influenced by a decreased number of surgical complications in the acrylic series. These data support the need to conduct a randomized prospective clinical trial to compare the relative safety and effectiveness of the two methods of embolization.

Intrathrombus administration of tissue plasminogen activator in acute cerebrovascular occlusion.

Intraarterial thrombolysis for acute cerebrovascular occlusion has achieved recanalization at a 50-90% rate. Clinical outcome has been unpredictable. The authors sought to test the hypothesis that intrathrombus administration of recombinant tissue plasminogen activator (rt-PA) would improve recanalization rate and to assess the possibility that clinical outcome would be predicted by the extent of collateral flow. Seven patients with acute cerebrovascular occlusion (less than six hours in 6, twenty-four hours in 1) were treated with intrathrombus rt-PA at 1 mg/minute. Examinations were scored on a five-point motor scale. Collateral flow was assessed angiographically. Vessels recanalized in 5 patients, 3 of whom had good outcomes. Vessels failed to recanalize in 2 patients, 1 of whom had good outcome. Good collateral flow was evident in all 4 patients with good outcome and in none of those with poor outcome. Intrathrombus administration of rt-PA is technically feasible. Favorable clinical outcome is more likely in the presence of good collateral flow. In the absence of good collateral flow, ultra-early intervention may be necessary.

Efficacy of endovascular treatment of meningiomas: evaluation with matched samples.

PURPOSE: To evaluate the clinical efficacy, cost-effectiveness, and safety of presurgical devascularization of meningiomas. METHODS: Matched samples of embolized and nonembolized groups of meningiomas were compared. The study variables for clinical efficacy were estimated blood loss, number of transfusions, surgical resection time, and length of hospitalization. The cost-effectiveness was evaluated by adjusting all hospital costs to 1991 dollar amounts, and adding additional embolization costs and fees to the hospital cost totals for the embolized group. A qualitative comparison of complications was made. RESULTS: All dependent variables evaluating the clinical efficacy of the procedure (estimate blood loss, 533 cc versus 836 cc; number of transfusions, 0.39 units versus 1.56 units; surgical resection time, 305.8 minutes versus 337.5 minutes; and length of hospitalization, 10.6 days versus 15.0 days) displayed trends of higher means in the nonembolized group; however, only the estimated blood loss and number of transfusions variables were significant. The cost-effectiveness of the procedure was not statistically significant. The mean cost was $29,605 for the embolized group and $38,449 for the nonembolized group. There were three major and nine minor complications in the nonembolized group and zero major and six minor complications in the embolized group. There were four additional minor complications caused by the embolization procedure. CONCLUSION: Endovascular devascularization of meningiomas is beneficial for large meningiomas because it diminishes the necessity of intraoperative transfusions and decreases blood loss. The additional day of hospitalization, emolization costs, and costs of complications do not conversely increase treatment costs. There were no major complications or adverse long-term effects caused by the embolization procedure.

Neurologic complications of cerebral angiography.

PURPOSE: To examine the incidence of neurologic complications associated with modern cerebral angiography and to assess patient characteristics associated with an increased risk of complications. METHODS: One thousand consecutive cerebral angiographic procedures were evaluated prospectively. Examinations were performed using transfemoral catheterization and film-screen methods. For purposes of this trial, a neurologic complication was defined as any new focal neurologic deficit or change in mental status occurring during the angiogram or within the following 24 hours. Patients were evaluated during and at the completion of angiography. Follow-up evaluations were performed on the day of and the day after angiography. RESULTS: There were a total of 10 neurologic complications within 24 hours of angiography, 5 of which were persistent. Onset of 5 of the deficits occurred during angiography, the other 5 (3 persistent) were delayed. All complications occurred in patients being evaluated for stroke/transient ischemic attack or (in one case) asymptomatic bruit. A higher average age, longer average procedure time, and greater volume of radiographic contrast was noted in these patients than in the study population. CONCLUSION: Cerebral angiography was associated with a 1% overall incidence of neurologic deficit and a 0.5% incidence of persistent deficit. All complications occurred in patients presenting with a history of stroke/transient ischemic accident or carotid bruit, which may reflect the difficulty of performing angiography in this population at risk for atherosclerotic changes.

Materials and embolic agents for endovascular treatment.

The refinement in the intravascular techniques has revolved upon the development of new material and a better understanding of neurophysiology. Access has become less of a limitation, and more emphasis is now placed on getting the job done: closing a fistula, obliterating a malformation, or filling an aneurysm. Embolic materials available have greatly changed according to the indication at hand. The focus now is on the specific uses for the agent instead of toxicity or dose-response trials.

Evaluation of shared-view acquisition using repeated echoes (SHARE): a dual-echo fast spin-echo MR technique.

PURPOSE: To compare the clinical efficacy of a dual-echo fast spin-echo imaging technique, SHARE (share-view acquisition using repeated echoes), with conventional long-repetition-time spin-echo imaging. METHODS: Conventional spin-echo and SHARE fast spin-echo MR images of the brain were acquired in 50 randomized patients and interpreted separately in conjunction with the T1-weighted images. All images were reviewed independently by two neuroradiologists who were blinded to the clinical history and previous interpretations. RESULTS: The diagnoses rendered for the spin-echo and SHARE images were concordant in 48 of the 50 subjects (96%) by the first reader and in all 50 cases (100%) by the second reader. SHARE images were acquired in one-fourth of the imaging time yet image contrast, quality, and sensitivity to long T2 lesions were comparable. The SHARE technique was less sensitive to hemorrhagic residua. CONCLUSIONS: SHARE is a viable time-saving alternative to the conventional long-repetition-time pulse sequence. Although SHARE images are not as sensitive to magnetic susceptibility effects, the time saved using this technique could be used to perform a gradient-echo sequence when indicated.

High-dose gadoteridol in MR imaging of intracranial neoplasms.

Twelve patients with a high suspicion of brain metastases by previous clinical or radiologic examinations were studied in a phase III investigation with magnetic resonance (MR) imaging at 1.5 T after a bolus intravenous injection of 0.1 mmol/kg gadoteridol followed at 30 minutes by a second bolus injection of 0.2 mmol/kg gadoteridol. All lesions were best demonstrated (showed greatest enhancement) at the 0.3-mmol/kg (cumulative) dose, with image analysis confirming signal intensity enhancement in the majority of cases after the second gadoteridol injection. More lesions were detected with the 0.3-mmol/kg dose than with the 0.1-mmol/kg dose, and more lesions were detected with the 0.1-mmol/kg dose than on precontrast images. In this limited clinical trial, high-dose gadoteridol injection (0.3-mmol/kg cumulative dose) provided improved lesion detection on MR images specifically in intracranial metastatic disease.

Cerebral infarction: assessment of patterns using ultra-fast MR contrast imaging.

We describe a rapid MR imaging technique, applying functional analysis to images obtained during the tissue transit of injected contrast material into the cerebral circulation, which has potential for assessment of the altered hemodynamics in cerebral ischemia. This technique utilized turbo-FLASH imaging maximizing the T1 relaxivity properties of gadopentetate dimeglumine with positive contrast enhancement.

Cerebral hemodynamics and cerebral blood volume: MR assessment using gadolinium contrast agents and T1-weighted Turbo-FLASH imaging.

PURPOSE: To assess the degree and regional pattern of first-pass brain enhancement using dynamic MR imaging. MATERIALS AND METHODS: Ultrafast MR imaging (1.06-second acquisition time per image) was performed in 19 healthy subjects following a bolus IV injection of a gadolinium contrast agent; 36 patients with suspected pathology were studied using the same protocol. RESULTS: Calculated percent blood volumes were 4.9% for right cortical gray matter, 4.8% for left cortical gray matter, and 2.6% for white matter. Subtraction images were obtained that depicted the first pass "blood pool" pattern of enhancement (gray and white matter) which was significant. CONCLUSION: Preliminary evidence suggests utility for cerebral "blood pool" imaging, especially if reduced image acquisition times can be achieved.