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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

High resolution ultrasound assessment of the parotid gland.

A variety of neoplastic and non-neoplastic conditions may present with parotid swelling. It is rarely possible to predict the nature of a swelling on clinical grounds alone and accurate imaging is necessary for further assessment. The parotid glands are superficial structures and are readily amenable to high resolution ultrasound examination. Ultrasound is able to: differentiate possible benign from malignant neoplasms; demonstrate whether a palpable lesion arises within the parotid gland, or is periparotid in location; and identify those entities that may not need surgical intervention. In this article the sonographic features of a range of parotid pathologies are reviewed and examples illustrated and the role of ultrasound in parotid assessment is discussed.

Diagnosis, Differential↗

Adenomyoepithelioma of the breast: spectrum of disease with associated imaging and pathology.

OBJECTIVE: Our objective was to show the spectrum of biologic behavior associated with breast adenomyoepithelioma. This disease is a rare benign breast neoplasm characterized by proliferation of both epithelial and myoepithelial cellular elements. Malignant change of one or both cell types may occur and is thought to be associated with hematogenous, rather than lymphatic, metastasis. CONCLUSION: Three patients with benign and malignant adenomyoepithelioma were included in this study. The imaging and histopathologic findings in these three patients are illustrated, and the treatment of patients with this unusual tumor is discussed.

Aged↗

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↗

Ultrasound-guided biopsy in the evaluation of focal lesions and diffuse swelling of the parotid gland.

We describe the technique of ultrasound-guided core biopsy with a spring-loaded device in 54 patients who presented with palpable lesions of the parotid gland. Biopsy provided a sample suitable for histological analysis in all patients and was done quickly and safely under local anaesthesia. Initial diagnostic ultrasound confirmed the presence of focal palpable lesions and identified additional impalpable lesions in seven patients. Core biopsy was 100% accurate in differentiating benign from malignant disease. The diagnosis was accurate in 27 of the 28 patients who were subsequently operated on. Twenty-six patients avoided an unnecessary operation. The technique is also useful in patients with diffuse enlargement of the parotid gland and provides a core of tissue for accurate assessment of tissue architecture.

Adolescent↗

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↗

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↗

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↗

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↗

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↗

Funny turns.

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Cerebrospinal Fluid Rhinorrhea↗

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↗