Magnetic resonance angiography. II. Applications

The objective of this paper is to describe clinical applications of magnetic resonance angiography. The data used were obtained from recent articles on vascular and flow magnetic resonance imaging retrieved from Index Medicus 1988–91. Other contributions were from the 29th Annual Meeting of the American Society of Neuroradiology held in Washington DC in June 1991 and the 10th Annual Conference of the Society of Magnetic Resonance in Medicine in August 1991. The data are presented in such a way as to give the reader unfamiliar with magnetic resonance a basic insight into some of the new imaging techniques. Magnetic resonance imaging is advancing at a rapid rate. Magnetic resonance angiography is already finding many areas of clinical use with concomitant reduction in conventional angiographic and duplex Doppler ultrasound procedures.     

Magnetic resonance angiography. I. Basic principles

The objective of this paper is to describe the basic physical principles important in magnetic resonance angiography (MRA). The data used were obtained from recent articles on MRA retrieved from Index Medicus 1985–92 and direct experience working with prototype MRA sequences. The information is presented in a manner suitable for those unfamiliar with the principles of MRA and magnetic resonance imaging (MRI). Magnetic resonance angiography is an important method that can be used to obtain angiograms without the injection of intravascular contrast medium. It is already proving to be of clinical use in the assessment of vascular disease.     

Anomalous communication of external carotid and vertebral arteries with associated intracranial parenchymal arteriovenous malformation: Magnetic resonance angiography and angiographic findings

A case of anomalous communication of the external carotid and vertebral arteries via a pro‐atlantal intersegmental artery (PIA) with an associated intracranial parenchymal arteriovenous malformation (AVM) is presented. The course of the PIA is displayed by both conventional catheter angiography and by MR angiography (MRA). To our knowledge, neither an associated intracranial parenchymal AVM nor depiction of this congenital anomaly on MRA has been previously described. We also briefly review the embryology and anatomy of this anomaly.     

Magnetic resonance findings in knee dislocation: Pictorial essay

Magnetic resonance images depicting the range of soft‐tissue and bony injuries associated with knee dislocation are presented. Those injuries that are less well described or more difficult to diagnose are emphasized.     

Coronary artery anomalies diagnosed by magnetic resonance angiography

Coronary artery anomalies are uncommon entities that may be associated with sudden death. Because of its 2‐D projection imaging nature, conventional X‐ray coronary angiography may not accurately delineate the origins and course of aberrant coronary arteries with respect to the great vessels. Non‐invasive, cross‐sectional imaging techniques such as coronary CT angiography and magnetic resonance angiography are increasingly used in clinical practice to diagnose coronary artery anomalies. Although this study reviews coronary artery anatomy and selected anomalies as seen with true fast imaging with steady‐state precession magnetic resonance angiography, the information provided is equally applicable to electrocardiogram‐gated coronary CT angiography.     

Double-chambered right ventricle: Magnetic resonance imaging findings

Primary double-chambered right ventricle is an uncommon congenital anomaly that presents with right ventricular outflow tract obstruction in childhood or adolescence. A search of the literature revealed only a few documented case reports with MRI findings. We present a case with mixed lesions, and with anomalous muscle bundles located both in the middle portion of the right ventricular sinus and at the subinfundibular level.     

Non-traumatic spinal extradural haematoma: Magnetic resonance findings

Non-traumatic extradural spinal haematoma is an uncommon condition that is usually associated with a poor outcome. It may present acutely with signs and symptoms of major neurological dysfunction secondary to cord compression, or subacutely over a number of days or weeks with fluctuating symptoms. The exact aetiology of this condition is incompletely understood, but it is believed that the blood is venous in origin, as distinct from the arterial origin of intracranial extradural haematomas. Causes of non-traumatic extradural spinal haematoma include anticoagulation, vasculitis such as systemic lupus erythematosus (SLE), and spinal arteriovenous malformations. Conditions that may mimic an acute spinal haematoma include extradural abscess and extradural metastatic infiltration. It is important to make a diagnosis of extradural compression because surgery may offer the best hope in restoring neurological function in these patients. Imaging modalities used for the investigation of extradural haematomas include myelography, CT myelography (CTM) and MRI with or without gadolinium enhancement. The MR appearances of acute extradural abscess and extradural tumour can mimic an extradural haematoma. In subacute haematoma, owing to the magnetic properties of blood degradation products, MR is more specific in diagnosing and ageing of the haematoma.     

Bilateral optic pathway glioma with intracranial calcification: Magnetic resonance imaging and magnetic resonance spectroscopy findings

Optic nerve glioma is the most common primary neoplasm of the optic nerve in childhood. It can extend intracranially along the optic pathway (optic pathway glioma). The lesion tends to present with decreased visual acuity in the affected eye, but can cause additional symptoms when it is large. Local involvement within the orbit can be characterized using CT, but MRI is superior in showing the intracranial extent of the lesion. Intracranial calcification in optic pathway glioma is rare. We present a rare case of optic pathway glioma with calcification in the intracranial component. Also, we describe MR spectroscopy (MRS) findings in this case.     

Multislice computed tomography angiography of the abdominal arteries: Comparison between computed tomography angiography and digital subtraction angiography findings in 52 cases

Since the introduction of multislice CT scanners, CT angiography (CTA) has become a powerful tool for imaging the vascular system. We compare conventional angiography to CTA in the diagnosis of morphological changes in the abdominal aorta and its branches. A retrospective analysis of 52 patients who underwent both multislice CT angiography (MSCTA) and digital subtraction angiography before surgical treatment is presented. All CT examinations were performed after administration of 100 mL contrast medium with a collimation of 4 × 1 mm and a pitch of 7. A standardized evaluation of the axial, multiplanar and 3D reconstructions was performed by two experienced radiologists. Stenoses were classified as high‐grade and low‐grade, and aneurysms, occlusions and arteriosclerosis were evaluated. The CTA findings were compared with conventional angiography. All aneurysms, occlusions, stenoses and calcifications were diagnosed correctly by CTA in axial and multiplanar projections (sensitivity 1.0; specificity 1.0). The degree of stenosis was overestimated in three cases when using axial projections. Three‐dimensional volume‐rendered CTA showed a sensitivity of 0.91 for aneurysms, 0.82 for stenoses, 0.75 for occlusions and 0.77 for calcifications. The specificity was 1.0 in all cases. Multislice CT angiography seems to be similar to conventional digital subtraction angiography for abdominal vessels if multiplanar projections are used.     

Role of magnetic resonance imaging in the early diagnosis of Takayasu arteritis

Takayasu arteritis is a non‐specific inflammatory process of unknown aetiology affecting the aorta and its major branches. It may lead to stenosis or occlusion. We have examined eight patients with clinically diagnosed Takayasu arteritis using contrast‐enhanced MRI and also 3‐D MR angiography. All patients were female and their ages varied between 22 and 48 years. We were able to show subtle arteritic changes and stenotic lesions in branch vessels in the early phase of the disease by using this imaging modality. Thus, we can state that contrast‐enhanced MRI with 3‐D MR angiography can be used for the initial diagnosis of Takayasu arteritis. It provides a means to evaluate the vascular tree non‐invasively and may replace conventinal angiography.     

Direct communication between the right pulmonary artery and the left atrium: Magnetic resonance findings

A case of direct communication between the right pulmonary artery and the left atrium is presented with the imaging findings that confirmed the diagnosis including magnetic resonance imaging.     

Magnetic resonance imaging of cerebrotendinous xanthomatosis

Cerebrotendinous xanthomatosis is a rare familial sterol storage disease with accumulation of cholestanol and cholesterol particularly in xanthomas, bile and brain. Magnetic resonance imaging is a useful modality for imaging the affected tissues. It contributes to the evaluation and management of the disease.     

Tandem lesions of the carotid circulation: Combined extracranial endarterectomy and intracranial transluminal angioplasty

A case series is presented demonstrating a unique approach to the treatment of tandem atherosclerotic lesions of the internal carotid artery. Between 1994 and 1999 eight patients with tandem lesions of the internal carotid artery were treated by combined carotid endarterectomy for the proximal lesion and intraoperative angioplasty of the distal intracranial lesion via the carotid arteriotomy. The success and complication rates were evaluated. A 100% technical success rate was achieved with one post procedural complication by ipsilateral stroke within 24 h. The advantages of this technique include the treatment of tandem lesions by the one procedure, improved transluminal access to the intracranial lesion and the ability to reduce the risk of embolism by flow control during balloon inflation.     

Isolated intrapetrous carotid canal atraumatic internal carotid artery dissection: MRI and digital subtraction angiography findings

A case of spontaneous internal carotid artery (ICA) dissection confined to the intrapetrous carotid canal that was confirmed by angiography and magnetic resonance imaging is presented. Isolated dissection involving the intrapetrous ICA is rare; however, whenever arterial dissection is a consideration, specific review of imaging in this region is warranted.     

Three‐dimensional gadolinium‐enhanced magnetic resonance angiography of pulmonary arteriovenous malformation

Pulmonary arteriovenous malformations (AVMs) are rare vascular malformations of the lung. Although most patients are asymptomatic, AVMs can bleed and result in haemoptysis and haemothorax. We describes a case of pulmonary AVMs in a patient with Osler–Weber–Rendu syndrome with 3‐D contrast‐enhanced MR angiography. Magnetic resonance angiography provided accurately and non‐invasively the number and size of the feeding arteries and draining veins.     

Idiopathic hypereosinophilic syndrome: Magnetic resonance imaging findings in endomyocardial fibrosis

Significant eosinophilia and even eosinophilic tissue infiltration has been associated with a variety of clinical disorders including allergic and immunodeficiency states, drug reaction, infection, parasitic infestation and malignancy. Eosinophilia without an underlying aetiology and with multi‐organ dysfunction has been designated idiopathic hypereosinophilic syndrome. We report a case of endomyocardial fibrosis with MRI findings.     

Cardiac metastasis from carcinoid tumour: Magnetic resonance imaging findings

A case of myocardial metastasis from a gastrointestinal carcinoid is presented. The colon was the primary site. The patient did not manifest symptoms of carcinoid syndrome and had no echocardiographic or MRI evidence of carcinoid valvular heart disease.     

Magnetic resonance imaging of the wrist in early rheumatoid arthritis: A pictorial essay

This pictorial essay describes the changes seen in the wrist in early rheumatoid arthritis (RA) on MRI. Magnetic resonance imaging can demonstrate bone erosions, bone marrow signal changes, synovitis and tenosynovitis in early rheumatoid arthritis. Magnetic resonance imaging of the wrist can identify erosions in RA earlier than plain radiographs and can detect more erosions. Common sites include the capitate, lunate and scaphoid. Bone marrow signal changes occur frequently and are most common in the capitate, lunate and triquetrum. Synovial thickening and enhancement are clearly demonstrated with MRI and are most commonly seen in the radiocarpal joint (RCJ). Tenosynovitis can be seen in the wrist in more than half of patients presenting with RA. This most commonly involves the extensor carpi ulnaris tendon and is seen as sheath fluid, thickening and enhancement.     

垂体转移瘤的临床与MR表现

目的：探讨垂体转移瘤的临床和MR表现。方法：收集垂体转移瘤20例,对其MR表现和临床资料进行回顾分析。结果：原发肿瘤包括乳腺癌5例,肺癌14例,结肠癌1例。主要临床表现有尿崩症（10例）、垂体前叶功能减退（2例）、头痛（4例）和视力下降（5例）等鞍区占位症状。转移灶位于垂体柄和（或）垂体后叶,呈浸润性生长,T1WI呈等、略低或等低不均匀信号,T2WI呈等、略高或等高混杂信号。结论：垂体转移瘤的临床和MR表现有一定特征,正确认识这些特征对临床诊断和治疗具有重要意义。     

Magnetic resonance imaging findings in fatal primary cerebral infection due to Chaetomium strumarium

This report describes MRI findings of a rare case of biopsy-proven fatal cerebral infection with Chaetomium strumarium in a 28-year-old man with a history of i.v. drug abuse. Magnetic resonance imaging revealed rapidly progressing lesions with irregular peripheral enhancement, possible central haemorrhage and significant mass effect. Only six cases of cerebral infection with Chaetomium have been reported in the English literature. This is the first report in the radiology literature describing the imaging findings. The previously reported cases of cerebral infection by the Chaetomium species are also reviewed.