Torsion of the upper lobe of the lung after surgery: findings on pulmonary angiography.
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Adult↗
Biomedical subjects
P L Munk
Publications and source records attributed to P L Munk.
Sonography of the eye.
Real-time sonography of the eye is a technique that is rapidly performed and readily available in most sonography departments. It is less expensive than CT and MR imaging and, if necessary, may be performed at the patient's bedside. This essay demonstrates a few of the large number of clinical entities that may be successfully examined with this technique.
Eye↗
The future of vascular surgery in Canada.
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Canada↗
Computed tomography of the knee.
Although magnetic resonance imaging (MRI) has become the imaging technique of choice in Canada and elsewhere in the evaluation of knee disorders, magnetic resonance units are frequently unavailable, or access to them is greatly restricted. The authors have found that computed tomography (CT) can sometimes be successfully substituted for MRI as a noninvasive method for imaging a wide variety of knee disorders. This article reviews the CT appearance of normal knee anatomy and illustrates a wide variety of pathological conditions that can be successfully evaluated.
Humans↗
Imaging techniques of the shoulder: present perspectives.
Through its ability to evaluate the individual components of the rotator cuff, the labral-capsular complex, the subacromial and subdeltoid spaces, and the glenoid, humerus, clavicle, and acromion, MRI provides a means of comprehensively evaluating the shoulder. Further advances in the use of intra-articular MRI contrast agents will undoubtedly enhance the role of MRI in the evaluation of subtle labralcapsular pathology. Although they are experimental, kinematic studies of the shoulder may provide valuable insight into the pathogenesis of disorders such as impingement syndrome. The ability of MRI to provide detailed pathologic information about individual components of the shoulder, particularly the rotator cuff, presents a challenge to shoulder surgeons. Patient symptomatology should be correlated with MRI findings and the clinical significance attached to different pathologies reevaluated. Through rigorous confirmation of MRI findings, dedicated therapeutic algorithms can be established based on detailed clinicopathologic data. Present and future surgical and nonsurgical management of the shoulder will undoubtedly be shaped by MRI.
Athletic Injuries↗
Recent advances in magnetic resonance imaging of musculoskeletal tumours.
Magnetic resonance imaging (MRI) has become the method of choice, where available, for the evaluation of musculoskeletal neoplasms. Recently, there has been interest and development in a number of areas in this field: (a) gradient-echo (fast-scan) sequences, which may often be substituted for more time-consuming T2-weighted sequences, are useful as localizing sequences and play an important role in intravenous contrast-enhanced scanning; (b) magnetic resonance contrast agents (e.g., gadolinium) improve delineation of tumours on static imaging and may help in estimating tumour aggressiveness with dynamic imaging; (c) STIR (short inversion time inversion recovery) increases lesion conspicuity; (d) spectroscopy, still an investigational area, may help in evaluating tumour response to chemotherapy and radiotherapy.
Bone Neoplasms↗
Magnetic resonance imaging of the shoulder: rationale and current applications.
Because it can demonstrate a wide range of tissue contrast with excellent resolution, magnetic resonance (MR) imaging has revolutionized imaging in many areas of the musculoskeletal system and has generated excitement among those interested in the painful shoulder. Shoulder impingement syndrome and glenohumeral instability constitute the two major categories of shoulder derangements. Correct diagnosis requires the use of appropriate pulse sequences and imaging planes, proper patient positioning, and a satisfactory surface coil. In addition the imager must have a thorough understanding of shoulder anatomy and pathology. We present a summary of the current status of MR imaging of the shoulder including technical, anatomic, and pathologic considerations and a review of the pertinent literature.
Humans↗
Epiphora: treatment by means of dacryocystoplasty with balloon dilation of the nasolacrimal drainage apparatus.
A new interventional radiologic procedure was developed for treatment of epiphora. A small-bore, soft-tipped guide wire was introduced through the superior canaliculus and guided under fluoroscopic control through the nasolacrimal drainage system for retrieval through the nasal aperture. A small-bore angioplasty catheter was then introduced in a retrograde direction into the nasolacrimal drainage apparatus and dilated under fluoroscopic control. The procedure was attempted in 18 eyes of 17 patients with moderate to severe epiphora and was technically completed in 16; 13 of these cases demonstrated improvement, with 11 patients showing complete resolution of symptoms. In the three patients whose epiphora did not improve, no worsening of symptoms occurred. These results are preliminary; follow-up ranged from 7 weeks to 6 months. The authors believe that this technique may hold promise in the treatment of epiphora and may obviate the use of more invasive procedures.
Catheterization↗
Pseudopermeative skeletal lesions.
Permeative bone lesions are well known to radiologists and usually invoke a differential diagnosis that includes aggressive lesions such as round cell malignancies and infection. In contrast to permeative lesions, which demonstrate multiple small holes at the endosteal surface of the cortex secondary to a medullary process, we describe a series of 19 patients (seven with aggressive osteoporosis, eight with prior radiation therapy and four with hemangiomas) who demonstrated multiple tiny lucencies in the cortex which were superimposed on the medullary space and mimicked a permeative pattern radiographically. We termed this a pseudopermeative pattern. Recognition of a pseudopermeative pattern may allow a less sinister differential diagnosis to be considered and may avert unnecessary biopsy in many instances.
Adult↗
Coloboma: evaluation with real-time sonography.
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Adult↗
Magnetic resonance imaging of the knee: current status, new directions.
A number of techniques for magnetic resonance imaging of the knee are reviewed. Spin-echo imaging sequences are at present the most widely used and are capable of demonstrating a wide range of pathology including cruciate and collateral ligament tears, meniscal abnormalities, and synovial disease. Fast scan imaging provides effective T2-weighting without the time penalty of T2-weighted spin-echo imaging. These fast scan techniques have also permitted the development of novel sequences including radial techniques and three-dimensional Fourier transform/volume acquisition (which may potentially become the imaging technique of choice in the knee). Inversion recovery may play an important role in evaluating cartilage disorders in the future. The strengths of each technique are discussed together with possible clinical applications.
Humans↗
Coronoid process hyperplasia: CT studies.
Coronoid process hyperplasia is a disorder that causes restricted jaw movement due to enlargement of the coronoid process of the mandible, which impinges on the zygomatic arch with mouth opening. The cause is unclear. Computed tomographic (CT) findings in three patients with this disorder (two bilateral, one unilateral)--including a 3-year-old boy who may be the youngest patient with this disorder ever reported--include an enlarged coronoid process, with sclerosis and erosion of the zygomatic arch. CT is an effective and rapid method for establishing the diagnosis.
Adult↗
Retrorenal colon: implications for percutaneous diskectomy.
It has been recommended that computed tomography (CT) with the patient prone be performed in every patient undergoing percutaneous diskectomy; this would enable detection of a retrorenal location of the colon, which could interfere with the percutaneous procedure. In this evaluation of 346 prone CT studies, only one patient (0.29%) was found to have retrorenal or retropsoas bowel that would have been perforated at diskectomy. Because of this extremely low prevalence, the performance of prone CT in every patient undergoing percutaneous lumbar diskectomy is not believed to be necessary.
Adolescent↗
Hypertrophy of C-1 anterior arch: useful sign to distinguish os odontoideum from acute dens fracture.
Dens fractures are often difficult to detect radiographically because of overlapping structures. The lateral radiographs were examined of all patients at the authors' institution who demonstrated an abnormal odontoid process or an abnormal anterior arch of C-1. Six patients were found: Four had os odontoideum, one had rheumatoid arthritis, and one had a congenital defect in the posterior arch of C-1. All had hypertrophy of the C-1 anterior arch on the lateral view. The width of the anterior arch of C-1 and the cortical thickness of the anterior arch in these six patients were measured and compared with the findings in a control group of 20 patients; the measurements from the six patients were found to be significantly greater. Hypertrophy of the anterior arch of C-1 is a useful sign of a chronic pathologic condition at the atlantoaxial articulation, and in the setting of acute trauma it may be an important clue that prevents unnecessary invasive treatment for a mistaken diagnosis of fractured dens.
Acute Disease↗
Dacryocystography: comparison of water-soluble and oil-based contrast agents.
Dacryocystography has been widely used in the assessment of the nasolacrimal duct system, particularly in patients with epiphora. Our study was undertaken to evaluate image quality and level of patient discomfort during examinations with water-soluble contrast agents (iohexol [Omnipaque 240], iopamidol [Isovue 200 and 300], and 52.7% diatrizoate meglumine and 26.9% iodipamide meglumine [Sinografin]) compared with the iodized oil-based contrast agent Lipiodol. Fifty-five dacryocystograms were obtained from 41 consecutive patients. The procedure was performed first with a water-soluble contrast agent, then repeated with Lipiodol. A distention technique was used with conventional radiography. Patients were asked to evaluate their level of discomfort (none, mild, moderate, severe). The images were evaluated separately by two radiologists, blinded to which water-soluble agent was employed, and the images were graded on a five-point scale. Images obtained with Lipiodol were significantly better than those with other agents (P less than .02), and image quality deteriorated as iodine concentration decreased. Use of Isovue 300 and Sinografin produced significantly more patient discomfort (P less than .03) than the use of other agents. The authors conclude that, in most instances, Lipiodol is the contrast agent of choice with regard to both highest level of patient comfort and greatest conventional radiographic image quality among the agents compared.
Contrast Media↗
Glenoid labrum: preliminary work with use of radial-sequence MR imaging.
The authors describe a magnetic resonance imaging method for examination of the glenoid labrum of the shoulder joint that utilizes a radial fast-imaging sequence. Seven shoulders were examined: a total of five in three healthy asymptomatic volunteers, one in a symptomatic patient not suspected of having a lesion of the glenoid labrum, and one in a patient with recurrent shoulder dislocation and surgical proof of an extensive tear of the labrum. The preliminary results suggest that this technique may advantageously demonstrate pathologic changes in the glenoid labrum and may contribute to the evaluation of the unstable and painful shoulder.
Adult↗
Immature bone infarcts: findings on plain radiographs and MR scans.
We studied the plain film findings in eight patients with immature bone-marrow infarction and correlated the findings with those of MR imaging in four of the cases. Seven patients had underlying systemic disease, including sickle cell disease (two), systemic lupus erythematosus (two), acute lymphocytic leukemia (one), non-Hodgkin lymphoma (one), and renal transplantation (one). In one patient, the bone infarct was idiopathic. Plain films in three of the eight cases were misinterpreted as showing aggressive lesions (i.e., malignancy or infection), and these patients underwent a biopsy that proved the diagnosis of bone infarction. In the other five cases, the diagnoses were established by clinical follow-up. The plain film findings in all eight cases consisted of subtle, mottled, ill-defined radiolucencies in the diametaphyseal region. Four of the patients had mild sclerosis. MR imaging in all four cases in which it was performed showed a central area with high or intermediate signal with a serpentine, thin, low-signal border. The lesions shown by MR imaging corresponded to the areas of abnormality on the plain films and had an appearance similar to that of previously reported bone infarcts. Our experience suggests that in patients with nonspecific subtle radiographic bone changes and an underlying systemic disease, MR imaging is helpful in establishing the diagnosis of bone marrow infarction.
Adolescent↗
MR imaging of aneurysmal bone cysts.
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Adolescent↗