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Biomedical subjects

D C Howlett

Publications and source records attributed to D C Howlett.

At least 19 recordsLinked to original sources
PubMed2002

The role of imaging in the evaluation of parotid disease.

In this review the imaging features of a range of parotid lesions are presented and the roles of ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI) in the assessment of parotid disease are discussed.

Adenolymphoma↗
PubMed2000

Calcified epidermoid cyst in the testis: an unusual finding on ultrasound.

Epidermoid cysts of the testis are uncommon, benign testicular tumours. They are often seen on ultrasound as rounded, hypoechoic lesions due to high keratin contents. Calcification within epidermoid cysts is rare. We report a case of prominent calcifications within an epidermoid cyst. If a possible epidermoid cyst is identified with ultrasound, testis-sparing surgery should be considered.

Calcinosis↗
PubMed2000

Pictorial review. Ultrasound of the testis.

Ultrasound examination is the primary imaging investigation used in initial evaluation of the symptomatic testis. In this review the ultrasound appearances of a range of testicular lesions are demonstrated. Particular attention is given to the subject of testicular microlithiasis and its link with germ-cell neoplasia, and also to the sonographic features of epidermoid cysts that may allow testis-sparing surgery.

Adolescent↗
PubMed1999

MRI of the brain in HIV-positive patients: what is the value of routine intravenous contrast medium?

Our purpose was to assess the value of routine administration of intravenous gadolinium-DTPA (Gd-DTPA) for cranial MR in a series of human immunodeficiency virus (HIV)-positive patients. Two radiologists retrospectively reviewed 150 consecutive examinations of 104 patients. All patients underwent unenhanced and contrast-enhanced images. Each radiologist independently assessed first the unenhanced images alone and then the pre- and postinjection images together. Then both reviewed the complete study and produced a consensus report. The history, investigations and management were collated separately and were unknown to the radiologists. Contrast-enhanced T1-weighted images showed new focal abnormalities, not seen on the T2-weighted or unenhanced images in 15 (14 %) patients, but almost always in the context of abnormal unenhanced images. In only 2 patients (2 %) did contrast medium reveal abnormalities when the unenhanced study had been considered normal. In only 1 of these (1 %) was the new finding, cytomegalovirus diffuse ependymal enhancement, of clinical importance, although the diagnosis of encephalitis was made on routine examination of cerebrospinal-fluid. The other revealed a toxoplasma lesion in a patient known to have resolving disease. Meningeal disease not suspected on the unenhanced images was shown in 2 patients (2 %). In these case the unenhanced images were abnormal in other respects. Intravenous Gd-DTPA was helpful to the radiologist in making a radiological diagnosis in 11 patients (11 %), usually by improving characterisation of a lesion seen on the unenhanced images. The contribution of intravenous Gd-DTPA in this series does not warrant recommending its use in every case.

AIDS Dementia Complex↗
PubMed1999

Ultrasound-guided cutting-needle biopsy of the parotid gland.

We describe the technique of ultrasound-guided 18 gauge (1.2 mm) needle biopsy in 16 patients with parotid gland lesions. This provides material suitable for histological analysis and can be performed quickly and safely under local anaesthesia. Thirteen of the patients had non-diagnostic blind fine-needle aspiration cytology (FNAC) with a 21 gauge (0.8 mm) needle prior to biopsy. Initial ultrasound was found to be superior to clinical examination in 31 per cent of cases. The ultrasound-guided technique provided a diagnostic specimen in 100 per cent of patients and was helpful where FNAC had been inconclusive. There was a diagnostic accuracy of 100 per cent in the patients who underwent subsequent surgery. This method should be considered when FNAC is non-diagnostic and surgical treatment is being considered. It is particularly useful in patients with diffuse enlargement of the gland and does provide a core of material for accurate assessment of tissue architecture. In this series, nine patients avoided unnecessary surgery.

Adolescent↗
PubMed1998

Multiple lower limb non-ossifying fibromas in siblings with neurofibromatosis.

Non-ossifying fibromas are common benign lesions of tubular long bones. There is recognized association of these bony lesions with neurofibromatosis type 1 although the presence of non-ossifying fibromas in familial members with the condition has not previously been reported. We report two siblings with neurofibromatosis and radiological evidence of multiple lower limb non-ossifying fibromas. Both patients presented with pain in the knees and a pathological fracture was observed in one case. Patients with multiple non-ossifying fibromas should be examined carefully for other evidence of neurofibromatosis.

Adolescent↗
PubMed1998

Funny turns.

Explore the source record for details and available documents.

Cerebrospinal Fluid Rhinorrhea↗
PubMed1998

Imaging the thoracic manifestations of AIDS.

Pulmonary complications occur in over half of patients with AIDS at some point in their illness. A chest X-ray is a valuable first-line investigation. The plain film and computed tomographic features of these complications are described and several examples illustrated. The role of computed tomography, including high resolution scanning techniques in further investigation and management, is discussed.

AIDS-Related Opportunistic Infections↗
PubMed1997

In vivo proton magnetic resonance spectroscopy in polymyositis and dermatomyositis: a preliminary study.

The aim of the study is to determine whether biochemical abnormalities, such as lipid, creatine and choline metabolites, are observed in the more distal muscles of polymyositis (PM) and dermatomyositis (DM) patients. 12 patients suffering from chronic active PM/DM and 9 controls underwent a combined proton magnetic resonance (MR) imaging and proton MR spectroscopy study of the calf muscle. From a combination of T1-weighted MR images and corresponding fat suppressed images, fat infiltration into the muscle of both PM and DM patients was consistently observed. Muscular atrophy with a variable distribution was also noted in all patients. The biochemical profile of the localised proton MR spectra of soleus muscle showed reduction of both 'choline' to lipid and 'creatine' to lipid ratios in chronic PM and DM patients when compared with controls.

Adipose Tissue↗
PubMed1997

Cyclosporine-related reversible posterior leukoencephalopathy: MRI.

Three patients aged 48, 11 and 40 years, two of whom were recent recipients of renal transplants and one of a bone marrow transplant, developed seizures, with cortical blindness in two cases. All were immunosuppressed with cyclosporine and were hypertensive at the onset of symptoms. MRI showed predominantly posterior signal changes in all three cases. The abnormalities were more conspicuous on fast FLAIR images than on conventional T2-weighted spin-echo images.

Adult↗
PubMed1997

Imaging and pathological features of primary malignant rhabdoid tumours of the brain and spine.

In this article two cases of primary malignant extrarenal rhabdoid tumour are described. In the affected children the brain and the spinal cord were the primary sites of origin of the tumour. The imaging findings are presented and the pathology discussed. Although the imaging features are non-specific, rhabdoid tumour should be included in the differential diagnosis of childhood intracranial and spinal neoplasms.

Acquired Immunodeficiency Syndrome↗