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A D Vellet

Publications and source records attributed to A D Vellet.

At least 37 records · Page 2Linked to original sources
PubMed1993

Producing picture-perfect posters.

Scientific posters form an integral part of many radiology meetings. They provide the opportunity for interested parties to read the material at an individualized pace, to study the images in detail, and to return to the exhibit numerous times. Although the content of the poster is undoubtedly its most important component, the visual presentation of the material can enhance or detract from the clarity of the message. With the wide availability of sophisticated computer programs for desktop publishing (DTP), one can now create the poster on a computer monitor with full control of the form as well as the content. This process will result in a professional-appearing poster, yet still allow the author the opportunity to make innumerable revisions, as the poster is visualized in detail on the computer monitor before printing. Furthermore, this process is less expensive than the traditional method of typesetting individual sections separately and mounting them on cardboard for display. The purpose of this article is to present our approach to poster production using commercially available DTP computer programs.

Computer Graphics↗
PubMed1993

Three-dimensional sonographic reconstruction: techniques and diagnostic applications.

In this review, we summarize the techniques of obtaining and reconstructing three-dimensional (3D) sonograms in a number of anatomic areas, catalog the clinical efforts at 3D sonography so far, and introduce more recent work in this area that takes advantage of the unique features of sonography. Although it is an active area of 3D imaging research, cardiac 3D imaging is not discussed because it has unique requirements stemming from the heart's anatomic inaccessibility and motion. Image analysis and display also are not covered, as no clear consensus has been reached about the usefulness of the large number of available methods.

Female↗
PubMed1993

Sonography of ocular choroidal melanomas.

Ocular choroidal melanomas lend themselves particularly well to evaluation by sonography. This essay illustrates the different appearances of ocular melanoma as depicted with sonographic imaging, including conventional gray-scale sonography and duplex Doppler, color flow Doppler, and three-dimensional display.

Choroid↗
PubMed1993

Lesions of cartilage and bone around the knee.

A variety of bone and cartilage abnormalities can be demonstrated on magnetic resonance imaging (MRI), which can play an important role in the diagnosis and management of these abnormalities. Ischemic bone lesions, including medullary bone infarction, primary osteonecrosis, and the osteochondroses, can be precisely evaluated as to their anatomic locations and relationship to overlying cartilage. Osteochondritis dissecans may also be diagnosed and staged. Presence of subchondral fractures and bone contusions, which are frequently associated with ligament and meniscal injuries, can also be diagnosed and followed; these conditions may play a role in the evolution of osteoarthritis. The changes of osteoarthritis, including cartilage abnormalities, cyst formation, and loose bodies, can be evaluated; this evaluation may be important in the assessment of therapies. Stress fractures often have characteristic appearances, and MR may be used in making this diagnosis, especially when symptoms and other imaging are unclear. Diffuse marrow disorders including hemoglobinopathies and neoplasia are also well demonstrated.

Bone Diseases↗
PubMed1993

Magnetic resonance imaging of a giant nonfunctioning retroperitoneal paraganglioma.

The authors describe the magnetic resonance imaging (MRI), computed tomographic, ultrasonographic and angiographic appearance of a giant nonfunctioning retroperitoneal paraganglioma. To their knowledge, the MRI appearance of a nonfunctioning paraganglioma has not been previously described. The MRI characteristics of the nonfunctioning tumour were similar to those of a functioning paraganglioma and included hyperintensity in T2-weighted images and intense enhancement after intravenous administration of contrast agent.

Adolescent↗
PubMed1993

The role of colour flow Doppler ultrasonography in the investigation of disease in the eye and orbit.

Colour flow Doppler ultrasonography is a relatively new technique in which colour-encoded representations of flowing blood are imposed over a conventional grey-scale ultrasound image. This allows interrogation of a relatively large volume of tissue to determine the presence and direction of blood flow. The waveform tracings are then evaluated by means of conventional Doppler imaging. We demonstrate examples of normal vascular structures in the orbit and describe the application of this technique in the investigation of vascular disease, such as carotid-cavernous fistula and ischemic disease. The technique can also be used to evaluate ocular membranes and masses. Colour flow Doppler imaging promises to be an important advance in ophthalmic ultrasonography.

Blood Flow Velocity↗
PubMed1993

Excimer-laser-assisted angioplasty in chronic femoropopliteal occlusion: the significance of an intimal flap in predicting reocclusion.

Angioplasty assisted by excimer laser was performed on 27 chronic femoropopliteal occlusions, ranging from 2 to 30 cm in length, in 26 patients. Twenty-one (78%) of the procedures were successful initially. Of these, 12 (57% [44% of the total]) remained patent at follow-up 3 months later. In seven of the nine cases of reocclusion observed after 3 months (78%) a large intimal flap resulting from the angioplasty-induced dissection could be identified in the postprocedure angiogram. The authors stress the possible importance of such an intimal flap in limiting the success of laser-assisted angioplasty of long femoropopliteal occlusions.

Adult↗
PubMed1993

Dynamic abdominal computed tomography: "top-down" compared with "bottom-up" imaging.

Dynamic contrast-enhanced computed tomography (CT) of the liver is usually performed from the top down, and there is usually less opacification of the top slices than the more inferior slices. The authors reasoned that reversing the direction of scanning would allow more time for the parenchyma at the top of the liver to become enhanced and would result in better opacification of the parenchyma and the hepatic veins. To test this hypothesis they assigned 32 patients to either a "top-down" or a "bottom-up" group; each patient then underwent unenhanced and contrast-enhanced CT. The method of intravenous administration of contrast agent was identical in the two groups and consisted of rapid injection of 135 mL of iohexol by a power injector; scanning was initiated 30 seconds after the injection was started. Attenuation measurements were obtained at specified areas in the liver and in the hepatic and portal veins. The degree of enhancement was calculated at each site and was compared between groups. The upper portion of the liver showed significantly greater enhancement in the bottom-up sequence than in the top-down sequence (123% and 22% respectively; p < 0.01); the entire liver showed excellent enhancement in the bottom-up sequence. In addition, the hepatic veins showed significantly greater conspicuity in the bottom-up sequence (p < 0.01). The authors conclude that the dynamic bottom-up method yields excellent hepatic enhancement and vascular opacification and is therefore superior to the standard top-down method.

Adult↗
PubMed1993

Leaking Baker's cyst detected by magnetic resonance imaging.

Popliteal or Baker's cysts, often found incidentally during examination of the knee, are common. The authors report the magnetic resonance imaging (MRI) manifestations of a leaking Baker's cyst that initially presented as thrombophlebitis in a patient who had undergone reconstruction of the anterior cruciate ligament 4 months before; no cyst was present at the time of the surgery. Marked inflammatory changes apparent in the surrounding muscle and subcutaneous tissues were best appreciated in T2-weighted and fat-suppressed inversion recovery images. Although the results of ultrasonography suggested the diagnosis, they were not conclusive; MRI was a useful noninvasive adjunct in making the definitive diagnosis.

Adult↗
PubMed1993

Intravenous administration of gadolinium in the evaluation of rheumatoid arthritis of the shoulder.

The authors sought to determine the utility of intravenously administered gadolinium chelates in magnetic resonance imaging (MRI) of patients with rheumatoid arthritis of the shoulder. One shoulder was examined for each of 12 patients--6 men and 6 women, ranging in age from 48 to 71 (average 63) years--with well-established disease. The patients had had the disease for 1 to 25 (average 13) years. Static MRI was performed before and after infusion of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) (0.1 mmol/kg body weight); T1-weighted or proton-density images (repetition time [TR] 600 to 1000 ms, echo time [TE] 15 to 30 ms) were obtained. Images obtained after enhancement were particularly useful in the differentiation of pannus from fluid and also allowed improved delineation of tears of the supraspinatus tendon. In addition, contrast-enhanced dynamic gradient-echo spoiled GRASS sequences (TR 50 ms, TE 11 ms, flip angle 70 degrees) were obtained for all patients; for these sequences the same slice was imaged repeatedly at 20-second intervals. The rate of increase of signal intensity in abnormal synovium varied from 0.64 to 5.83 (average 2.30, standard deviation [SD] 1.67) units/second; the enhancement factor ranged from 1.55 to 4.64 (average 2.63, SD 0.98). The authors conclude that for imaging the shoulder enhancement with Gd-DTPA allows improved distinction between synovial thickening and joint effusion and may improve assessment of the rotator cuff. The wide range in the rate of signal increase and total enhancement during dynamic imaging probably reflected heterogeneity in the study population.

Acromioclavicular Joint↗
PubMed1993

Soft tissue sarcomas: a plea for proper management.

Although soft tissue sarcomas are relatively uncommon, they often occur in young patients and if properly treated are often curable. Unfortunately, inappropriate approaches to biopsy before adequate staging may compromise a successful outcome. The roles of diagnostic imaging (particularly magnetic resonance imaging) in adequate preoperative evaluation and staging and the fundamental principles of surgical management are discussed.

Adolescent↗
PubMed1993

Sonolucent peripancreatic masses: differential diagnosis and related imaging.

The most common cause of a sonolucent mass in the epigastrium is a pancreatic pseudocyst; however, several other conditions can simulate a pseudocyst on ultrasonography (US) scans. This pictorial essay illustrates the spectrum of conditions that may present in this fashion and demonstrates the use of other imaging modalities, such as colour-flow and pulsed Doppler US, computed tomography, magnetic resonance imaging and angiography, in their evaluation.

Abscess↗
PubMed1993

Tears of the medial collateral ligament: magnetic resonance imaging findings and associated injuries.

For 23 patients with a surgically proven tear of the medial collateral ligament the findings from magnetic resonance imaging (MRI) of the knee were evaluated retrospectively. MRI revealed the tear in all cases, although when the injury was severe, distinguishing high-grade partial tears from complete tears was difficult. Physical examination had indicated a tear in 22 (96%) of the cases. A high prevalence of associated cruciate and meniscal injuries was seen (in 23 [100%] and 12 [52%] of the cases respectively). Tears of the fibular collateral ligament occurred in 13 (57%) of the patients and at least one bony infraction in 22 (96%); most of the infractions were in the lateral compartment. Infractions of the lateral femoral condyle were frequently geographic (in 14 [70%] of the 20 cases) or impacted (in 5 [25%]). The spectrum of injuries associated with tears of the medial collateral ligament was consistent with the findings of previous studies focusing on cruciate and meniscal abnormalities; the minor variations were likely due to the severity of valgus stress in this sample.

Adolescent↗
PubMed1992

Sciatic neuropathy associated with persistent sciatic artery.

Persistent sciatic artery is a congenital vascular anomaly of the arterial supply to the lower extremity. Thrombosis, distal embolization, aneurysmal dilatation, and rupture of this vessel with compression of the sciatic nerve have been recorded. Although rare in occurrence, complications of persistent sciatic artery should be included in the differential diagnosis of sciatic neuropathy. We present a case of an acute sciatic neuropathy secondary to pseudoaneurysm formation of a persistent sciatic artery. We demonstrate the diagnostic usefulness of magnetic resonance imaging.

Adult↗