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Biomedical subjects

D J Roebuck

Publications and source records attributed to D J Roebuck.

At least 37 records · Page 2Linked to original sources
PubMed1999

Risk and benefit in paediatric radiology.

An investigation requiring the use of ionising radiation can be justified by showing that its benefits are likely to exceed its risks. The risks can be estimated from the effective dose by using the system recommended by the International Commission on Radiological Protection. The benefits of investigations in paediatric radiology are currently unquantified. We can assume that some tests have potential benefits so large that further evaluation is unnecessary. Others have a maximum potential benefit so low that they can be discarded. For most investigations, however, research into the magnitude of benefit to the patient is required in order to establish that it is greater than the magnitude of the radiation risk.

Child↗
PubMed1999

Imaging following allograft reconstruction in children with malignant bone tumours.

PURPOSE: To determine the nature of the imaging findings following reconstructive surgery using massive allografts in children with malignant bone tumours. MATERIALS AND METHODS: A retrospective review of the imaging studies and medical charts of 25 consecutive children who received an allograft as part of the management of a malignant bone tumour. RESULTS: Uncomplicated allografts were sclerotic relative to native bone on radiographs and showed a typical 'tramline' appearance on bone scintigraphy. On MR, the medullary canal of the allograft showed low signal, similar to or greater than skeletal muscle, but less than subcutaneous fat, on 91 % of T1-weighted images. On short-tau inversion recovery images, the medullary canal was inhomogeneous and hyperintense to subcutaneous fat in 70 % and hyperintense to muscle in the remainder. Complications occurred in 68 % of patients and included allograft fractures (36 %), recurrent tumour (20 %), infection (8 %), and non-union or delayed union (8 %). The radiographic findings alone permitted accurate diagnosis of most serious complications. Infection and rejection were difficult to distinguish with any technique. All complications were suspected on clinical and/or radiological grounds before being shown by MR or scintigraphy. CONCLUSIONS: Allografts, whether normal or complicated, have characteristic imaging findings, except that infection and bone resorption related to rejection and revascularisation are difficult to distinguish. Routine MR and bone scintigraphy appear to contribute little to the management of these patients.

Adolescent↗
PubMed1999

Potential utility of MRI in the evaluation of children at risk of renal scarring.

BACKGROUND: Gadolinium-enhanced MRI has recently been employed in the diagnosis of acute pyelonephritis. Its potential utility in the diagnosis of renal scars in children is unknown. Objective. To evaluate the potential utility of MRI using fat-saturated T1-weighted (T1-W) and post-gadolinium, short-tau inversion-recovery (STIR) sequences in detecting renal scarring by comparison with technetium dimercaptosuccinic acid ((99 m)Tc-DMSA) renal scintigraphy in children at risk of renal scarring. MATERIALS AND METHODS: A group of 24 children with spina bifida and neurogenic bladder or anorectal anomaly was studied. No patient had a history of acute pyelonephritis. Documented urinary tract infection (UTI) was present in 10 children (42 %). The remaining 14 (58 %) children had a history of asymptomatic bacteriuria. None had clinical signs or symptoms of acute UTI at the time of the study. (99 m)Tc-DMSA and MRI were performed to detect renal scarring. (99 m)Tc-DMSA scans were supplemented with pinhole imaging. MRI of the kidneys employed a fat-saturated T1-W sequence and a post-gadolinium STIR sequence employing a short echo time. RESULTS: Of the kidneys studied, 33 % (n = 16) had evidence of a renal parenchymal defect suggestive of scarring on (99 m)Tc-DMSA. The concordance in the detection of a scarred kidney by post-gadolinium STIR sequence and (99 m)Tc-DMSA is 94 %; that by fat-saturated T1-W sequence and (99 m)Tc-DMSA is 82 %; that by both sequences (positive result on either sequence) and (99 m)Tc-DMSA is 100 %. Using (99 m)Tc-DMSA as the gold standard, MRI had a sensitivity of 100 % and a specificity of 78 % in the diagnosis of a scarred kidney. The concordance in the detection of a scarred zone by post-gadolinium STIR sequence and (99 m)Tc-DMSA is 68 %; that by fat-saturated T1-W sequence and DMSA is 44 %; that by both sequences (positive result on either sequence) and (99 m)Tc-DMSA is 84 %. MRI had a sensitivity of 84 % and a specificity of 86 % in the diagnosis of a scarred zone, using (99 m)Tc-DMSA as the gold standard. CONCLUSION: The detection rate for renal scarring on MRI using the fat-saturated T1-W and post-gadolinium STIR sequences is comparable to planar (99 m)Tc-DMSA. MRI is of potential utility in the evaluation of children at risk of renal scarring.

Anal Canal↗
PubMed1999

Breast metastasis in osteosarcoma.

A young girl with a history of chondroblastic osteosarcoma of the tibia developed a pulmonary metastasis which was treated by metastasectomy, chemotherapy and lung irradiation. There years later, at the age of 15, she developed a breast mass which was excised and which proved to be a poorly differentiated sarcoma. This was almost certainly a metastasis rather than a radiation-induced second primary tumour, in view of the short interval since radiotherapy. The ultrasonographic features of this lesion are presented here and the differential diagnosis is discussed in this context.

Bone Neoplasms↗
PubMed1999

How sensitive is ultrasound in the detection of renal scars?

The English language medical literature was reviewed to determine the strength of the published evidence for the assertion that dimercaptosuccinic acid scintigraphy (DMSA) is superior to ultrasound (US) in the detection of established renal scarring in children. The MEDLINE database was used to identify papers published between 1985 and 1997 that claimed to be concerned with the detection of scars, and contained sufficient information to permit calculation of the sensitivity of US relative to DMSA. Only 10 studies were identified. The sensitivity of US for scarring, using DMSA as a gold standard, ranged from 37% to 100%, and its specificity from 65% to 99%. These wide ranges mean that evaluation of the role of US in the detection of scarring remains controversial. All papers contained methodological flaws. Allowing for these, the sensitivity of US appears to be acceptable. Further research that avoids these methodological problems is required.

Child↗
PubMed1998

Burton skeletal dysplasia: the second case report.

We describe a 2-year-old girl with clinical and radiological findings of Burton skeletal dysplasia. This rare disorder shows some similarities to Kniest dysplasia. Short stature, joint stiffness, microstomia, and pursed lips are characteristic clinical findings. Platyspondyly with cervical kyphosis, but no coronal clefts, and bowing of the long bones are distinctive radiographic findings.

Bone and Bones↗
PubMed1998

Hepatobiliary rhabdomyosarcoma in children: diagnostic radiology.

Rhabdomyosarcoma (RMS) occurs infrequently in the liver and biliary tree. Although the radiological diagnosis may be simple when the tumour involves the extrahepatic bile ducts, no specific imaging features are known for hepatic RMS. We present four cases and discuss the role of diagnostic radiology in the management of this tumour.

Biliary Tract Neoplasms↗
PubMed1998

The role of ultrasound and oesophagography in the management of acute suppurative thyroiditis in children associated with congenital pyriform fossa sinus.

The thyroid is remarkably resistant to infection. Hence, when an infection does occur, the presence of a pyriform fossa sinus must be considered, particularly if it is recurrent and left sided. The aim of this paper is to alert radiologists to the existence, clinical presentation, and ultrasonographic and oesophagographic appearances of a pyriform fossa sinus. We present the role of ultrasound and oesophagography in five children with pyriform fossa sinus associated with suppurative thyroiditis. In four children the abnormality was on the left and on the right in one.

Abscess↗
PubMed1998

Cryptococcosis in HIV negative patients: findings on chest radiography.

BACKGROUND: The findings at chest radiography in HIV negative patients with cryptococcosis are said to differ from those in HIV positive patients. No large series of HIV negative patients has been reported. METHODS: A review of the medical charts and radiographs of 44 consecutive HIV negative patients with proven cryptococcosis was undertaken. RESULTS: Air space consolidation involving one or more lobes was found in 15 patients (34%), one or more pulmonary masses in 13 patients (30%), and interstitial opacities in three patients (7%). No other radiographic finding was detected in more than one patient. Twelve of 23 patients (52%) with cryptococcal meningitis had abnormal chest radiographs, and 10 of 16 patients (62%) who presented with respiratory symptoms had air space consolidation. CONCLUSIONS: HIV negative patients tend to have different radiographic findings from those reported in patients with AIDS. Cryptococcal meningitis in this group is usually associated with pulmonary mass(es) or a normal chest radiograph, whereas a respiratory presentation is usually associated with air space consolidation.

Adolescent↗
PubMed1998

A technique for enhancing union of allograft to host bone.

The aim of limb-salvage surgery in malignant bone tumours in children is to restore function and eradicate local disease with as little morbidity as possible. Allografts are associated with a high rate of complications, particularly malunion at the allograft-host junction. We describe a simple technique which enhances union of allograft to host bone taking advantage of the discrepancy in size between the adult allograft and the child's bone. This involves lifting a flap of periosteum before resection from the host bone, which is then telescoped into the allograft medullary canal, which may require internal burring or splitting, for a distance of 1.5 to 2 cm and covering the bone junction with the periosteal flap. This is more stable than conventional end-to-end opposition. For each centimetre of telescoping the surface area available for bony union is increased more than three times. The periosteal flap also augments union. Additional surface fixation with a plate and screws is not necessary. We have used this technique in nine children, in eight of whom there was complete union at a mean of 16 weeks. Delayed union, associated with generalised limb osteoporosis, occurred in one. Early mobilisation, with weight-bearing by three weeks, was possible. There was only one fracture of the allograft.

Bone Neoplasms↗
PubMed1998

Cat-scratch disease with an extraaxial mass.

CT and MR imaging of the brain and gallium-67 scintigraphy showed an enhancing, gallium-avid mass in the left middle cranial fossa of a 10-year-old girl. Craniotomy revealed an inflammatory mass related to the left trigeminal nerve. The lesion contained rodlike bacteria, and serologic tests were positive for cat-scratch disease. Neurologic involvement in cat-scratch disease is uncommon, and the presence of organisms in neural tissue has not been reported.

Bartonella henselae↗