Magnetic Resonance Imaging Angiogram Research Articles

Acute‐Onset Oculomotor Paresis Attributed to Isolated P1 Occlusion Successfully Treated by Mechanical Thrombectomy

Objective Case report of acute‐onset oculomotor paresis attributed to thrombotic occlusion of the perforator‐bearing P1 segment of the posterior cerebral artery with preserved perfusion of the basilar tip and P2 segment in the presence of a posterior communicating artery successfully treated by mechanical thrombectomy. Conclusions Short‐segment thromboembolic P1 occlusion can present as acute‐onset oculomotor paresis, so acute diplopia is an appropriate indication for performing a computed tomography or magnetic resonance imaging angiogram as mechanical thrombectomy appears to be an effective therapeutic option.

Takayasu's Arteritis: A Case Report.

aortitis syndrome; arteritis; case reports; pulseless disease; young female arteritis.

Fluorescently-tagged magnetic protein nanoparticles for high-resolution optical and ultra-high field magnetic resonance dual-modal cerebral angiography.

Extremely small paramagnetic iron oxide nanoparticles (FeMNPs) (<5 nm) can enhance positive magnetic resonance imaging (MRI) contrast by shortening the longitudinal relaxation time of water (T1), but these nanoparticles experience rapid renal clearance. Here, magnetic protein nanoparticles (MPNPs) are synthesized from protein-conjugated citric acid coated FeMNPs (c-FeMNPs) without loss of the T1 MRI properties and tagged with fluorescent dye (f-MPNPs) for optical cerebrovascular imaging. The c-FeMNPs shows average size 3.8 ± 0.7 nm with T1 relaxivity (r1) of 1.86 mM-1 s-1 and transverse/longitudinal relaxivity ratio (r2/r1) of 2.53 at 11.7 T. The f-MPNPs show a higher r1 value of 2.18 mM-1 s-1 and r2/r1 ratio of 2.88 at 11.7 T, which generates excellent positive MRI contrast. In vivo cerebral angiography with f-MPNPs enables detailed microvascular contrast enhancement for differentiation of major blood vessels of murine brain, which corresponds well with whole brain three-dimensional time-of-flight MRI angiograms (17 min imaging time with 60 ms repetition time and 40 μm isotropic voxels). The real-time fluorescence angiography enables unambiguous detection of brain capillaries with diameter < 40 μm. Biodistribution examination revealed that f-MPNPs were safely cleared by the organs like the liver, spleen, and kidneys within a day after injection. Blood biochemical assays demonstrated no risk of iron overload in both rats and mice. With hybrid neuroimaging technologies (e.g., MRI-optical) on the rise, f-MPNPs built on this platform can generate exciting neuroscience applications.

Anatomical description of the umbilical arteries and impact of their ligation on pelvic and perineal vascular supply after cystectomy in women.

In radical cystectomy, the surgeon generally ligates the umbilical artery at its origin. This artery may give rise to several arteries that supply the sexual organs. Our aim was to evaluate pelvic and perineal devascularisation in women after total cystectomy. We carried out a prospective anatomical and radiological study. We performed bilateral pelvic dissections of fresh adult female cadavers to identify the dividing branches of the umbilical artery. In parallel, we examined and compared the pre- and postoperative imaging investigations [magnetic resonance imaging (MRI) angiography] in patients undergoing cystectomy for benign disease to quantify the loss of pelvic vascularisation on the postoperative images by identifying the occluded arteries. The anatomical study together with the radiological study visualised 35 umbilical arteries (n = 70) with their branching patterns and collateral arteries. The uterine artery originated from the umbilical artery in more than 75% of cases (n = 54) of the internal pudendal artery in 34% (n = 24) and the vaginal artery in 43% (n = 30). The postoperative MRI angiograms showed pelvic devascularisation in four patients. Devascularisation was dependent on the level of surgical ligation. In the four patients with loss of pelvic vascular supply, the umbilical artery had been ligated at its origin. The umbilical artery gives rise to various branches that supply the pelvis and perineum. If the surgeon ligates the umbilical artery at its origin during total cystectomy, there is a significant risk of pelvic and perineal devascularisation.

Automatic labeling of cerebral arteries in magnetic resonance angiography.

In order to introduce 4D flow magnetic resonance imaging (MRI) as a standard clinical instrument for studying the cerebrovascular system, new and faster postprocessing tools are necessary. The objective of this study was to construct and evaluate a method for automatic identification of individual cerebral arteries in a 4D flow MRI angiogram. Forty-six elderly individuals were investigated with 4D flow MRI. Fourteen main cerebral arteries were manually labeled and used to create a probabilistic atlas. An automatic atlas-based artery identification method (AAIM) was developed based on vascular-branch extraction and the atlas was used for identification. The method was evaluated by comparing automatic with manual identification in 4D flow MRI angiograms from 67 additional elderly individuals. Overall accuracy was 93%, and internal carotid artery and middle cerebral artery labeling was 100% accurate. Smaller and more distal arteries had lower accuracy; for posterior communicating arteries and vertebral arteries, accuracy was 70 and 89%, respectively. The AAIM enabled fast and fully automatic labeling of the main cerebral arteries. AAIM functionality provides the basis for creating an automatic and powerful method to analyze arterial cerebral blood flow in clinical routine.

A Patient With Internal Carotid Artery Dissection

The purpose of this case report is to raise physical therapist awareness of Horner syndrome as a "red flag" for immediate medical referral. A 45-year-old man sought physical therapy for examination and treatment of neck pain and headache symptoms 5 days after experiencing a whiplash-type injury while waterskiing. His complaints were similar to a prior condition diagnosed as occipital neuralgia that had successfully responded to education, cervical and thoracic joint mobilization, and exercise provided by a physical therapist. The initial examination findings also were similar to those of the previous episode. However, signs consistent with Horner syndrome were noted on the second visit. This finding raised immediate concern on the part of the treating clinician and resulted in prompt physician referral, medical diagnosis, and intervention. A magnetic resonance imaging angiogram revealed an internal carotid artery dissection. A successful outcome was achieved over the course of 6 months through medical intervention, which consisted of anticoagulant therapy and modification of activity levels. In this case, the patient's sudden onset of signs of Horner syndrome was indicative of a medical emergency-internal carotid artery dissection.

Allograft morphology and function in heart transplant recipients surviving more than 15 years by magnetic resonance imaging and dual-source computed tomography

Cardiac allograft vasculopathy and late graft failure are the main limiting factors of long-term success of heart transplantation, and little is known about graft function in the long-term survivors. The aim of this study was to assess the ventricular function and the allograft vasculopathy in long-term survivors (>15 years) with the cardiac magnetic resonance imaging (MRI) and dual-source computed tomography (DSCT) coronary angiogram. In our database, 34 cardiac recipients have more than 15 years of follow-up and were evaluated for this study; 22 (65%) of them were enrolled. Mean age at transplant was 46 ± 13.5 years, mean donor age was 28.5 ± 10.1 years, and mean graft ischemic time was 189 ± 58 min. Mean follow-up was 18.5 ± 2.4 years (range 15-22). All patients underwent cardiac MRI and DSCT. Mean left ventricular (LV) volumes indexed to the body surface area (BSA) were within normal range: the end-diastolic volume/BSA was 61 ± 16 ml m(-2), end-systolic volume/BSA was 22 ± 15 ml m(-2), stroke volume/BSA was 38 ± 6 ml m(-2), LV mass/BSA: 72 ± 18 g m(-2), and mean ejection fraction (EF) was 0.59 ± 0.08. Two patients (9%) showed a global cardiac hypokinesia and two other patients (9%) showed akinesia of one segment. At DSCT, 41% of patients had a strictly normal coronary angiogram, 41% had wall thickening and 18% presented a least one >60% stenosis. Cardiac MRI and DSCT coronary angiogram revealed a normal graft function and morphology after more than 15 years of transplantation. However, a certain number of patients have significant cardiac allograft vasculopathy and another consistent group has initial disease. These patients deserve further follow-up and tailoring of the immunosuppressive regimen.

Digital Ischemia After Carpal Tunnel Injection: A Case Report

Payne JM, Brault JS. Digital ischemia after carpal tunnel injection: a case report. A 51-year-old woman described paresthesias in her right thumb, index, and middle fingers consistent with carpal tunnel syndrome. Using a sterile technique, a 25-G, 1¼-in needle was introduced ulnar to the palmaris longus tendon, and a mixture of 1.5mL of 40mg/mL of triamcinolone acetonide and 1.5mL of 1% lidocaine was injected. After the injection, the patient's hand exhibited signs of ischemia including coolness and discoloration. Rewarming of the hand with paraffin was performed immediately, and normative color returned. At follow-up visits, the patient described burning in the hand, and blotchiness of the digits was noted. A magnetic resonance imaging angiogram of the right wrist showed a single deep palmar arch. Electromyography and nerve conduction study weeks after the injection showed bilateral median neuropathies, moderately severe on the right and mild on the left. She underwent an open carpal tunnel release 6 weeks postinjection. The patient did well and returned to her job without restrictions. The exact etiology of the hand ischemia is unclear but may be related to vasospasm as has been described in the spine-injection literature. Regardless of the etiology, this case shows an uncommon adverse event in a commonly performed procedure and raises questions for further review.

Cardiac cycle–dependent left atrial dynamics: Implications for catheter ablation of atrial fibrillation

Left atrial (LA) volume determines prognosis and response to therapy for atrial fibrillation. Integration of electroanatomic maps with three-dimensional images rendered from computed tomography and magnetic resonance imaging (MRI) is used to facilitate atrial fibrillation ablation. The purpose of this study was to measure LA volume changes and regional motion during the cardiac cycle that might affect the accuracy of image integration and to determine their relationship to standard LA volume measurements. MRI was performed in 30 patients with paroxysmal atrial fibrillation. LA time-volume curves were generated and used to divide LA ejection fraction into pumping ejection fraction and conduit ejection fraction and to determine maximum LA volume (LA(max)) and preatrial contraction volume. LA volume was measured using an MRI angiogram and traditional geometric models from echocardiography (area-length model and ellipsoid model). In-plane displacement of the pulmonary veins, anterior left atrium, mitral annulus, and LA appendage was measured. LA(max) was 107 +/- 36 mL and occurred at 42% +/- 5% of the R-R interval. Preatrial contraction volume was 86 +/- 34 mL and occurred at 81% +/- 4% of the R-R interval. LA ejection fraction was 45% +/- 10%, and pumping ejection fraction was 31% +/- 10%. LA volume measurements made from MRI angiogram, area-length model, and ellipsoid model underestimated LA(max) by 21 +/- 25 mL, 16 +/- 26 mL, and 35 +/- 22 mL, respectively. Anterior LA, mitral annulus, and LA appendage were significantly displaced during the cardiac cycle (8.8 +/- 2.0 mm, 13.2 +/- 3.8 mm, and 10.2 +/- 3.4 mm, respectively); the pulmonary veins were not displaced. LA volume changes significantly during the cardiac cycle, and substantial regional variation in LA motion exists. Standard measurements of LA volume significantly underestimate LA(max) compared to the gold standard measure of three-dimensional volumetrics.

Bundle branch reentry ventricular tachycardia in arrhythmogenic right ventricular dysplasia

A 42-year-old male had history of recurrent palpitation and was documented to have wide QRS tachycardia. Magnetic resonance imaging angiogram showed evidence of arrhythmogenic right ventricular dysplasia and severe right ventricular dysfunction. Electrophysiology study showed evidence of bundle branch reentry ventricular tachycardia. It was successfully treated by radiofrequency ablation of right bundle branch. This is probably the first case of bundle branch reentry as a mechanism for ventricular tachycardia in a case of arrhythmogenic right ventricular dysplasia.

Functional anatomy of the prostate: Implications for treatment planning

To summarize the functional anatomy relevant to prostate cancer treatment planning. Coronal, axial, and sagittal T2 magnetic resonance imaging (MRI) and MRI angiography were fused by mutual information and registered with computed tomography (CT) scan data sets to improve definition of zonal anatomy of the prostate and critical adjacent structures. The three major prostate zones (inner, outer, and anterior fibromuscular) are visible by T2 MRI imaging. The bladder, bladder neck, and internal (preprostatic) sphincter are a continuous muscular structure and clear definition of the preprostatic sphincter is difficult by MRI. Transition zone hypertrophy may efface the bladder neck and internal sphincter. The external "lower" sphincter is clearly visible by T2 MRI with wide variations in length. The critical erectile structures are the internal pudendal artery (defined by MRI angiogram or T2 MRI), corpus cavernosum, and neurovascular bundle. The neurovascular bundle is visible along the posterior lateral surface of the prostate on CT and MRI, but its terminal branches (cavernosal nerves) are not visible and must be defined by their relationship to the urethra within the genitourinary diaphragm. Visualization of the ejaculatory ducts within the prostate is possible on sagittal MRI. The anatomy of the prostate-rectum interface is clarified by MRI, as is the potentially important distinction of rectal muscle and rectal mucosa. Improved understanding of functional anatomy and imaging of the prostate and critical adjacent structures will improve prostate radiation therapy by improvement of dose and toxicity correlation, limitation of dose to critical structures, and potential improvement in post therapy quality of life.

Congenital absence or hypoplasia of the carotid artery: Radioclinical issues

Purpose Congenital anomaly of the carotid artery is a rare abnormality. It is usually discovered incidentally by color Doppler carotid sonography, angiography, computed tomography (CT), or magnetic resonance imaging (MRI) of the head and neck taken for some other reason. Most patients are not symptomatic because of sufficient cerebral circulation supplied to the defective area by the communicating arteries of the circle of Willis, intercavernous anastomosis, communicating arteries from external carotid artery, and by persistent embryologic arteries to the carotid artery territory. However, sometimes, this anatomic variation may eventually lead to some clinical signs and symptoms in particular circumstances in the head and neck of which surgeons are unaware. A retrospective study was designed to emphasize the characteristic radiologic and clinical picture in patients with the congenital absence (agenesis and aplasia) or hypoplasia of the carotid artery, to delineate the associated abnormalities and existing collateral vessels, and to find out its incidence. Material and methods Five thousand one hundred cerebral MRI and/or catheter angiograms performed between February 1988 and March 2002 were reviewed for carotid artery abnormality. Results Seven patients with congenital absence or hypoplasia (4 of these patients were presented with hypoplasia of internal carotid artery [ICA], 3 with absence of ICA) of ICA were identified (0.13%). The radiologic and clinical study of 5 patients with unilateral (3 of these patients were presented with hypoplasia and 2 with absence of ICA) and 2 patients with bilateral (1 was presented with absence of ICA, whereas the other was hypoplasia) congenital abnormality with absence or hypoplasia of ICA demonstrate that those patients are usually asymptomatic and they are diagnosed incidentally. Conclusion It has been concluded that the combined use of magnetic resonance angiography and CT scanning of the skull base may disclose small but patent ICA. Collateral vessels seem to be usual in such cases, but they may be prominent in cases of acquired vascular occlusion, or increased hemodynamic pressure in dysplastic changes in collateral arteries are known causes of aneurysms. The main vascular supply for the brain in patients with congenitally small (hypoplasia) or absent (agenesis or aplasia) ICA is the vertebrobasilar system in bilateral cases. However, contralateral carotid vessel is the dominant arterial supply for unilateral cases, which has to be borne in mind in surgical interventions to the involved side.

Titanium Aneurysm Clips: Part III Clinical Application in 16 Patients with Subarachnoid Hemorrhage

This report describes the first clinical use of newly developed titanium clips in the treatment of 16 patients with subarachnoid hemorrhage. There were no immediate or delayed complications related to the titanium clips. Thirteen patients had good outcomes, and one patient had moderate disabilities (mean follow-up, 5.4 mo). Two patients with Hunt and Hess Grade IV hemorrhages died postoperatively. The average cross-sectional areas of clip artifact on postoperative magnetic resonance imaging studies was 0.96, 1.36, and 1.05 cm2 on T1-, T2-, and intermediate-weighted images, respectively. In comparison, a matched control group with cobalt alloy clips had average cross-sectional areas of 3.13, 3.70, and 2.81 cm2 on T1-, T2-, and intermediate-weighted images, respectively. The average artifact volumes on gradient echo magnetic resonance images for titanium and cobalt alloy clips were 1.8 and 10.1 cm3, respectively. In addition, the gap on magnetic resonance imaging angiograms from clip artifacts was 0.9 cm with titanium and 2.6 cm with cobalt alloy clips. In conclusion, titanium aneurysm clips seem to be safe and effective and seem to reduce clip artifacts on magnetic resonance imaging threefold, compared with commercially available cobalt alloy clips. Because of this important advantage over conventional clips, titanium clips should be considered for routine use in aneurysm surgery.

Titanium Aneurysm Clips: Part III-Clinical Application in 16 Patients with Subarachnoid Hemorrhage

THIS REPORT DESCRIBES the first clinical use of newly developed titanium clips in the treatment of 16 patients with subarachnoid hemorrhage. There were no immediate or delayed complications related to the titanium clips. Thirteen patients had good outcomes, and one patient had moderate disabilities (mean follow-up, 5.4 mo). Two patients with Hunt and Hess Grade IV hemorrhages died postoperatively. The average cross-sectional areas of clip artifact on postoperative magnetic resonance imaging studies was 0.96, 1.36, and 1.05 cm2 on T1-, T2-, and intermediate-weighted images, respectively. In comparison, a matched control group with cobalt alloy clips had average cross-sectional areas of 3.13, 3.70, and 2.81 cm2 on T1-, T2-, and intermediate-weighted images, respectively. The average artifact volumes on gradient echo magnetic resonance images for titanium and cobalt alloy clips were 1.8 and 10.1 cm3, respectively. In addition, the gap on magnetic resonance imaging angiograms from clip artifacts was 0.9 cm with titanium and 2.6 cm with cobalt alloy clips. In conclusion, titanium aneurysm clips seem to be safe and effective and seem to reduce clip artifacts on magnetic resonance imaging threefold, compared with commercially available cobalt alloy clips. Because of this important advantage over conventional clips, titanium clips should be considered for routine use in aneurysm surgery.

Evaluation of complex congenital ventricular anomalies with magnetic resonance imaging

Complex ventricular anomalies are frequently associated with abnormalities of thoracic and abdominal situs, arterioventricular connection, and venous connection. The definition of all components of these anomalies is difficult to accomplish with imaging techniques. This study compared the effectiveness of electrocardiographic (ECG) gated spin-echo magnetic resonance imaging (MRI) with cardiac angiography for the evaluation of all components of central cardiovascular anatomy in patients with the clinical diagnosis of single or common ventricle or complete atrioventricular (AV) septal (canal) defect. MRI studies and angiograms of 29 patients were evaluated independently. A sequential approach was used to define cardiac anatomy assessing nine anatomic features in each patient. MRI provided 261 observations and angiography provided 209 observations. In the mutual 209 observations, only 17 discrepancies were found. Comparison of MRI and angiography in individual cases showed that MRI was as effective as angiography in the depiction of ventricular anomalies, including determination of morphology and evaluation of the size of the ventricles, the orientation of the ventricular septum relative to the AV valves, as well as the origins and spatial relationships of the great arteries. MRI was more informative for the determination of thoracic and abdominal situs and systemic and pulmonary venoatrial connections, but was not as effective for the evaluation of semilunar valves. Thus MRI provides complete evaluation of central cardiovascular anatomy and is effective in the anatomic assessment of most components of complex ventricular anomalies.

The diagnosis of thyrotoxicosis.

<h3></h3> Atrial fibrillation (AF) is the major arrhythmia seen in humans after 60 years of age. The role of identifying the foci inducing this arrhythmia is crucial because ablation techniques have gained importance in returning to sinus rhythm. Cardiovascular magnetic resonance imaging (MRI) has an important role in identifying theses foci. MRI studies were done using a Philips machine with a 1.5 Tesla magnet. The heart was evaluated with the following pulse sequence cardiac gated T-1 weighted coronal and cine G.R.E. horizontal long axis. This was followed by a gadolinium enhanced MRI angiogram. Emphasis was given to the junction of the right atrium and pulmonary veins, as well as the superior vena cava, inferior vena cava and left atrium. Measurements were done in patients (P) with intermittent chronic AF and normals. The data were analyzed statistically. We found statistically significant changes (p &lt; .05) in the left superior pulmonary vein diameter in patients with intermittent and chronic AF and in right superior pulmonary vein diameter between intermittent AF and controls. Statistically significant changes (p &lt; .05) were also seen in the inferior vena cava between controls and chronic AF and in the left superior pulmonary vein between controls and chronic AF. No changes were seen in the left atrium between chronic and intermittent AF. This shows the importance of MRI imaging in identifying the possible foci (dilatation of structures) of AF. This identification will reduce the average time required to convert AF to normal sinus rhythm.