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C W Heron

Publications and source records attributed to C W Heron.

At least 19 recordsLinked to original sources
PubMed2001

Contrast-enhanced magnetic resonance angiography of the iliac arteries: optimization by injection simulation.

Protocols for contrast-enhanced magnetic resonance angiography (CE-MRA) of the iliac arteries were optimized by computer simulations based on an impulse response function (IRF) of contrast agent (CA) concentration as a function of time obtained for 20 patients. Protocols with sequential, centric, and elliptical k-space coverage, different repetition rates (5 and 10 ms), and CA doses (0.1, 0.2, and 0.3 mmol/kg b.w.) were compared in terms of signal-to-noise ratio (SNR), distortion of vessel profiles, and sensitivity to timing errors. IRF-based simulations successfully characterized CA recirculation. Slow-rate CA infusions were found to achieve relatively high enhancement. In terms of SNR, there is no advantage in increasing the repetition rate. Distortion of vessel profiles is more likely in elliptic and centric k-space coverage. Protocols based on sequential k-space coverage and relatively long CA infusions proved to be particularly suited to large-FOV iliac examinations as they are relatively insensitive to timing errors.

Adult↗
PubMed1996

A painful shoulder.

A case is outlined of a patient presenting with a painful shoulder. Metastatic malignant melanoma was diagnosed. The sites of origin of melanotic lesions as well as metastatic sites are described. Both gross and radiological appearances of such lesion are not uniform, varying from osteolytic to osteoblastic forms. Treatment is for the most part ineffective. The outcome is rapid and invariably fatal.

Aged↗
PubMed1995

MRI appearances of the asymptomatic patellar tendon on gradient echo imaging.

Thickening of the patellar tendon and foci of increased signal intensity have been described as characteristic features of "jumper's knee" (chronic patellar tendinitis) on magnetic resonance imaging (MRI). It was our impression that such appearances may be seen in the patellar tendons of patients without symptoms referable to the anterior part of the knee when using gradient echo images. The appearances of the asymptomatic patellar tendon on three-dimensional gradient echo sequences were studied by retrospectively reviewing the images of 60 patients, none of whom had symptoms related to the anterior part of the knee. The anteroposterior width of the patellar tendon was measured at three levels (superior, middle and inferior) on the central sagittal image of a gradient echo sequence. The relative signal intensities at the same levels were recorded. In 97% of subjects the superior part of the tendon was wider than the midpoint, and in 97% the inferior part was wider than the midpoint. The range of widths was wide, and there was no significant difference between sexes. Focal increased signal intensity in the superior part was shown in 75%, and in the inferior part in 43%. The asymptomatic patellar tendon shows uniform thickness throughout most of its length, but there are focal expansions at the proximal and distal ends. It usually demonstrates low signal on MRI, but may contain foci of increased signal intensity at either or both ends when imaged on gradient-echo sequences.

Adolescent↗
PubMed1993

Bowel preparation before intravenous urography: is it necessary?

Whether or not bowel preparation should be used before intravenous urography (IVU) remains a controversial issue. Despite strongly held views on both sides there is little scientific evidence to support either viewpoint. We have conducted a prospective randomized study designed to test the hypothesis that adequate bowel preparation before IVU facilitates better quality studies requiring fewer films and consequently less time and a lower radiation exposure. Data on 188 patients were analysed; 90 patients received bowel preparation and 98 received no bowel preparation. There was no difference between the groups in terms of the number of films taken, the duration of the procedure, the visibility of the renal tracts or the overall quality of the studies. The prepared group did have significantly less faecal residue than the unprepared group. However, the renal tract visibility was no greater, as the combination of gas and haustral folds seen after bowel preparation obscured fine detail of the urinary tract as effectively as faecal residue. The hypothesis that adequate bowel preparation before IVU facilitates better quality studies must therefore be rejected.

Cathartics↗
PubMed1993

Review article: MRI of the knee.

The inherent vulnerability of the knee to injury and degenerative change means that there is a major requirement for an imaging technique capable of assessing such damage accurately, rapidly and non-invasively. Over a relatively short time magnetic resonance imaging (MRI) has emerged as the technique of choice in the assessment of internal derangement of the knee. The present review describes the wide application of MRI to the knee and considers the position of MRI in relation to other diagnostic methods.

Cartilage, Articular↗
PubMed1992

Three-dimensional gradient-echo MR imaging of the knee: comparison with arthroscopy in 100 patients.

To compare the findings on magnetic resonance (MR) images of the knee obtained with a three-dimensional gradient-echo (GRE) sequence with findings at arthroscopy, the menisci, cruciate ligaments, and hyaline cartilage were assessed in 100 patients. At MR imaging (performed by means of fast imaging with steady-state precession) and arthroscopy, the menisci (n = 200) and areas of hyaline cartilage (n = 500) were assigned grades of zero (normal) to three (greatest abnormality). The cruciate ligaments were considered intact, partially torn, or completely torn. The sensitivity of MR imaging in diagnosis of meniscal tears seen at arthroscopy was 97% and the specificity, 94%. For complete tears of the anterior cruciate ligament, the sensitivity was 92% and specificity, 96%. In the posterior cruciate ligament, both the sensitivity and specificity were 100%. Good correlation existed between findings at MR imaging and those at arthroscopy in assessment of focal thinning and full-thickness loss of hyaline cartilage, but arthroscopy enabled superior visualization of minor fissuring. Three-dimensional GRE MR imaging enables accurate assessment of the articular cartilage of the knee. The evaluation of meniscal tears and the cruciate ligaments has a high negative predictive value.

Adolescent↗
PubMed1991

Spiking of the tubercles of the intercondylar eminence of the tibial plateau in osteoarthritis.

"Spiking", "sharpening" or "peaking" of the tubercles of the intercondylar eminence of the tibial plateau has been described as an early sign of osteoarthritis of the knee joint, but there are no reports confirming this association. The radiographs of 55 patients with established osteoarthritis of the knee joint and 36 controls were reviewed. Measurements were made of the angulation of the tips of the medial and lateral tubercles, and the ratio of the tubercle height to the width of the tibial plateau was calculated. There was a significant difference in both these parameters between the two groups, confirming that lengthening and sharpening of the angles of the tubercles are features of osteoarthritis of the knee joint.

Adult↗
PubMed1990

CT scanning as an adjunct to screening for medullary carcinoma of the thyroid.

CT scanning of the thyroid following oral administration of potassium iodate was performed on two sisters in whom raised calcitonin levels had been found at a pentagastrin stimulation test undertaken to screen for medullary carcinoma of the thyroid. Three histologically proven, clinically occult C-cell carcinomas measuring 2 mm or less were detected by CT scanning. This technique may be useful prior to surgery in patients in whom medullary carcinoma of the thyroid is suspected but not proven.

Adolescent↗
PubMed1989

Bladder cancer: staging with CT and MR imaging.

Magnetic resonance (MR) imaging and computed tomography (CT) were compared in 30 patients with histologically proved bladder cancer. MR imaging was accurate in depicting the presence or absence of extravesical spread in 22 patients (accuracy, 73%; sensitivity, 82%; specificity, 62%), and CT was accurate in 24 patients (accuracy, 80%; sensitivity, 94%; specificity, 62%). The MR examinations of two patients were of undiagnostic quality and therefore considered to be technical failures. Each technique resulted in five false-positive and one false-negative examination for the diagnosis of extravesical tumor spread. In 28 patients the integrity of the bladder wall was assessed with MR imaging. In 22 patients the bladder wall was disrupted, and 18 of these patients had deep muscle invasion. In six patients the bladder wall was intact, and none of these patients had evidence of deep muscle invasion at pathologic examination. In this study MR imaging was slightly inferior to CT in the delineation of invasive tumors beyond the bladder wall. However, if one excludes from analysis the two patients with undiagnostic studies, there is no significant difference in accuracy between the two techniques.

Adult↗
PubMed1989

Magnetic resonance imaging in recurrent carcinoma of the cervix.

Twenty patients with suspected recurrent cervical carcinoma were evaluated with computed tomography (CT) and high-field magnetic resonance imaging (MRI). Histological verification of the imaging findings were available in all cases. Computed tomography and MRI were equally effective in making the diagnosis of disease recurrence. The extent of vaginal recurrence and involvement of pelvic floor muscles was better shown on MRI than on CT.

Carcinoma, Squamous Cell↗
PubMed1988

The value of CT in the diagnosis of recurrent carcinoma of the cervix.

The results of computed tomography (CT) and other imaging techniques performed on 70 patients who were investigated for suspected recurrent carcinoma of the cervix are reported. Recurrent disease was present in 39 patients. In 29, there was local recurrence with or without distant metastases and there was distant recurrence only in 10. Computed tomography correctly assessed the presence of local recurrent disease in 85% of patients. Six equivocal, two false positive and two false negative CT examinations in the assessment of local recurrence were due either to difficulty in differentiating recurrent disease from changes following radiotherapy, or to the failure of CT to detect small areas of local recurrent disease. Ultrasound and lymphangiography each detected recurrence in one patient which was missed by CT, but this was the most reliable technique for the detection of both local and distant recurrent disease.

Adenocarcinoma↗
PubMed1988

Anomalous systemic venous drainage occurring in association with the hypogenetic lung syndrome.

A case in which anomalous systemic venous drainage occurred in association with the hypogenetic lung syndrome (scimitar syndrome) is described. The chest radiograph appearances of the anomalous systemic vein mimicked an anomalous pulmonary or scimitar vein. Angiography demonstrated that the patient also had a small anomalous pulmonary vein draining and a systemic artery supplying, the right lung. As the right lung was hypoplastic, all three features of the hypogenetic lung syndrome were present, in addition to partial anomalous systemic venous drainage.

Abnormalities, Multiple↗
PubMed1988

Hodgkin disease: CT of the thymus.

The computed tomography (CT) scans in two groups of patients with Hodgkin disease were reviewed to determine the frequency of thymic enlargement. In 50 CT scans from 50 patients with evidence of thoracic disease on CT scans who were examined for primary staging, the thymus was enlarged in 15 of 50 (30%). Fifty CT scans were obtained from 44 patients at the time of 50 separate episodes of known or suspected relapse. Relapse occurred in the mediastinum in 12 episodes, lung parenchyma in five, and both sites in one. Thymic enlargement thought to be due to involvement by disease was present in seven of 18 (38%). Mediastinal disease was associated with thymic enlargement in all but one patient in whom a thymic cyst developed after radiation therapy. Differentiation of thymic enlargement from enlarged superior mediastinal lymph nodes was easily made in all but two patients. Thymic enlargement in the absence of lymph node enlargement may indicate a different disease, since isolated Hodgkin disease of the thymus is uncommon. Primary thymic tumor should be considered initially, whereas after treatment, rebound hyperplasia of the thymus may be the cause of enlargement.

Adolescent↗
PubMed1988

The appearance of the inferior thyroid veins on computed tomography.

Computed tomography (CT) scans of the mediastinum in 80 patients were reviewed retrospectively to determine the nature of small opacities which are identified on contiguous cuts. These structures varied in number from one to five. The pattern of enhancement, appearance on contiguous CT sections and position in the mediastinum led us to believe that these represent inferior thyroid veins. To our knowledge their appearance on CT has not been reported previously.

Adult↗