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Biomedical subjects

D C Howlett

Publications and source records attributed to D C Howlett.

At least 55 records · Page 3Linked to original sources
PubMed1997

The role of CT and MR in imaging the complications of sickle cell disease.

Sickle cell disease is the most common inherited haemoglobinopathy described. Complications of sickle cell disease (SCD) are due to chronic haemolysis of fragile red cells or secondary to vascular occlusion by sickled red cells with subsequent tissue infarction. Traditionally plain film radiography has been the mainstay in the assessment of patients with SCD, but increasingly magnetic resonance (MR) imaging and computed tomography (CT) are being used. In this review the imaging features of a range of complications of SCD are demonstrated with particular emphasis on CT and MR.

Anemia, Sickle Cell↗
PubMed1997

Pictorial review: the imaging features of male breast disease.

Although breast carcinoma in men is rare, the presentation of a male patient with evidence of breast enlargement or of a palpable lump, is not uncommon. In such patients, radiological assessment may be requested to exclude malignant change. Mammography has been traditionally the dominant modality of investigation, although ultrasound, using high-frequency linear transducers, is playing an increasingly important role for both imaging and biopsy and the two techniques should be regarded as complementary. In this article the pathological conditions which may affect the male breast are reviewed and the imaging findings presented.

Adult↗
PubMed1997

Moyamoya disease.

Moyamoya disease is a rare cerebrovascular condition of uncertain aetiology commonly affecting young persons. The disease is mainly seen in Japanese patients. We report two cases of moyamoya disease in Caucasian women and review the postulated aetiological factors and associated conditions as well as the spectrum of invasive and non-invasive imaging modalities useful in the diagnosis and follow-up of the disease, with particular reference to the developing role of magnetic resonance imaging and angiography.

Adolescent↗
PubMed1997

The incidence of transient renal medullary hyperechogenicity in neonatal ultrasound examination.

A prospective ultrasound study of the urinary tracts of 85 neonates (64 term, 21 preterm) was performed to assess the incidence of transient renal medullary hyperechogenicity (RMH) in the first week of life. None of the neonates examined had evidence of renal dysfunction. Echogenic material was observed in the renal papillae/calyces, ureter, or bladder of 33 of the 64 term babies, but in the bladder of only one pre-term infant. The distribution of the echogenicity differs from that seen in medullary hyperechogenicity due to crystal deposition, suggesting that calyceal involvement is a common feature. Follow-up ultrasound scans at 10-14 days were possible in eight of the term neonates and demonstrated complete resolution of the RMH. The aetiology of transient neonatal RMH is unclear, although it may be related to protein cast deposition in the renal tubules. RMH may rarely be associated with transient renal dysfunction, but in healthy neonates should be recognized as a normal variant.

Female↗
PubMed1997

The ultrasound appearances of neonatal renal vein thrombosis.

Renal vein thrombosis (RVT) is the most frequently occurring vascular condition in the new-born kidney. The predisposing factors include dehydration, sepsis, birth asphyxia, maternal diabetes, polycythaemia and the presence of an indwelling umbilical venous catheter. (RVT) may present clinically with a flank mass, haematuria, hypertension or renal failure. Many imaging modalities have been employed, but ultrasound is the technique most commonly used in the evaluation of neonates with suspected RVT. Thrombosis commences in the small renal veins and subsequently propagates via larger interlobar veins to the main renal vein and inferior vena cava (IVC). The ultrasound appearances depend upon the stage at which the examination is performed and extent of the thrombus. Initially, the interlobular and interlobar thrombus appears as highly echogenic streaks. These streaks commence in a peripheral, focal segment of the involved kidney and only persist for a few days. In the first week the affected kidney swells and becomes echogenic with prominent echopoor medullary pyramids. Later, the swelling increases and the kidney becomes heterogenous with loss of corticomedullary differentiation. Grey scale ultrasound readily demonstrates thrombus within the renal vein and IVC. Adrenal haemorrhage is a recognized association and may be identified ultrasonically. Colour Doppler scanning provides additional information. In the early stages of RVT, colour Doppler may demonstrate absent intrarenal and renal venous flow. Ultimately, the kidney may recover, show focal scarring or become atrophic. Thus, ultrasound provides an accessible and reliable tool in the assessment of suspected neonatal RVT.

Humans↗
PubMed1996

The use of antibiotic prophylaxis in radiology departments for patients at high-risk of infective endocarditis.

Patients with a prosthetic heart valve, or a history of endocarditis are at particular risk of developing infective endocarditis during a bacteraemia which may follow many gastrointestinal and genito-urinary radiological procedures. The current British Society for Antimicrobial Chemotherapy guidelines (1992) do recommend antibiotic prophylaxis for these high-risk patients prior to instrumentation of the gastrointestinal or genito-urinary tracts. Routine antibiotic prophylaxis for patients with damaged native valves or heart murmurs is recommended prior to dental procedures only. A questionnaire enquiring about prescribing practice prior to several radiological investigations known to be associated with bacteraemia was sent to 192 radiology departments and 126 replied. Only 38 of the 126 respondents have a prescribing policy for antibiotic prophylaxis in high-risk groups. Fifty-eight departments employ antibiotic prophylaxis prior to one or more of the procedures named in the questionnaire, but only 30 of these have mechanisms for identifying at-risk patients. Forty-eight departments keep recommended antibiotics in the department.

Antibiotic Prophylaxis↗
PubMed1996

Ultrasound appearance of pseudomembranous colitis.

A case illustrating that ultrasound can be useful in the diagnosis of pseudomembranous colitis is reported. Diagnosis of pseudomembranous colitis is usually made from microbiological or histopathological investigations. The ultrasound appearance of grossly thickened bowel wall with luminal narrowing is non-specific, but in the correct clinical context should suggest the diagnosis of pseudomembranous colitis.

Enterocolitis, Pseudomembranous↗
PubMed1995

Computed tomography in the evaluation of cutaneous T-cell lymphoma.

The computed tomography (CT) scans performed in 28 patients with cutaneous T-cell lymphoma (CTCL) were reviewed. Fifteen patients had clinically advanced cutaneous mycosis fungoides, six patients Sézary syndrome and seven variant CTCL. Of the 40 scans available 12 were normal, 15 indeterminate and 13 abnormal. Indeterminate and abnormal nodes showed a predilection for inguinal and axillary sites with a relative sparing of deep nodal regions. Visceral involvement was infrequent. In six patients CT detected abnormalities not obvious clinically and upstaged the disease. CT should be performed as part of the initial staging and as a baseline for follow-up in patients with advanced mycosis fungoides, Sézary syndrome and variant CTCL.

Adult↗
PubMed1995

Symptomatic intracranial involvement by mycosis fungoides.

Involvement of the central and peripheral nervous system by mycosis fungoides is rare and usually occurs in the presence of widespread cutaneous and visceral disease. We describe a patient with mycosis fungoides, previously confined to the skin, who developed intracranial parenchymal disease with no evidence of systemic involvement.

Central Nervous System Diseases↗
PubMed1995

Case report: therapeutic transcatheter embolotherapy in the control of recurrent haemorrhage from lymphoma of the small bowel.

Lymphoma is one of the commonest primary malignancies of the small bowel. Gastrointestinal tract haemorrhage is a relatively infrequent presenting feature or complication. We describe the use of repeated transcatheter embolization as the primary treatment in the control of recurrent haemorrhage from the small bowel in a patient with B-cell lymphoma. Few cases of transcatheter embolotherapy have been described in such situations. This form of treatment is a therapeutic option in those unfit for transcatheter vasoconstrictor infusion or surgery.

Aged↗
PubMed1995

Case report: the role of arteriography in patients with isolated neurological deficit following a penetrating upper limb injury.

Two cases are described of patients who presented with isolated neurological deficit following penetrating injury to the upper limb. Arteriography demonstrated brachial artery false aneurysm formation in each case. There are accepted indications for emergency angiography following stab wounds including pulse deficit, vascular bruit, expanding haematoma and hypotension with no obvious cause. Indirect indicators of vascular damage include proximity of the injury to an artery with no physical signs or isolated neurological deficit. These indications do have a significant association with concurrent arterial injury and should be investigated by elective angiography if the patient is haemodynamically stable.

Adult↗