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Biomedical subjects

W C Peh

Publications and source records attributed to W C Peh.

At least 19 recordsLinked to original sources
PubMed1998

Day case hematuria diagnostic service: use of ultrasonography and flexible cystoscopy.

OBJECTIVES: To assess the efficacy of a day case diagnostic service employing ultrasonography and flexible cystoscopy in the evaluation of patients presenting with painless gross hematuria. METHODS: From July 1994 to June 1997 a prospective study was conducted for 312 consecutive patients presenting with painless gross hematuria. They were evaluated in a day case diagnostic service setting, where ultrasonography and flexible cystoscopy were performed together with other laboratory investigations. Intravenous urography was subsequently performed for possible additional diagnostic information. RESULTS: Eighty-one urinary malignancies were detected in 78 patients; 51 were carcinoma of the bladder, and the next most common was renal cell carcinoma (n = 15). Definitive diagnoses were made in 68 patients and an abnormality was noted in 9 other patients after the day case workup. The day case diagnostic workup has led to highly selective use of computed tomography scans with high diagnostic yield; intravenous urography only added important diagnostic information, not available from the earlier workup, in 9 patients. CONCLUSIONS: Day case diagnostic service is a feasible arrangement. By combining ultrasonography and flexible cystoscopy, most carcinomas were diagnosed and abnormalities detected. Such a service enhances rapid completion of diagnostic workup, and operations for surgical conditions can be scheduled more promptly.

Adolescent↗
PubMed1998

Intra-abdominal follicular dendritic cell tumour: a rare tumour in need of recognition.

AIMS: Neoplasms of follicular dendritic cells are uncommon and the majority of them occur in lymph nodes. Rarely, they may occur inside the abdominal cavity. We describe two examples of intra-abdominal follicular dendritic cell (FDC) tumour. One involved the liver and the other involved the ampulla of Vater. Our aims are to complement the current understanding on this disease and to alert histopathologists and clinicians to this rare entity. MATERIALS AND RESULTS: The clinical and radiological findings of the two cases of intra-abdominal follicular dendritic cell tumours were reviewed. The resected specimens were examined macroscopically and microscopically. Immunohistochemical studies, ultrastructural examination and in situ hybridization for Epstein-Barr virus were also performed. Both tumours could not be accurately diagnosed before pathological examination of the resected specimens. The soft to slightly firm consistency of the tumours resembled that of fixed brain tissue, and was distinctly different from hepatocellular carcinoma or pancreatic carcinoma. The fascicular arrangement of syncytial plump to spindle cells in a background of mixed inflammatory cells was the initial clue to the diagnosis, which was confirmed by the immunoreactivity of the tumour cells to follicular dendritic cell markers (CD21 and CD35), and by the demonstration of focal intercellular desmosome-like junctions between the complex cytoplasmic processes of the tumour cells. The tumour cells in the liver tumour also showed presence of Epstein-Barr virus on in situ hybridization study. CONCLUSIONS: Awareness of the entity and the ability to recognize this tumour by histopathologists are emphasized because the tumour closely mimics a wide variety of other tumours and tumour-like lesions. Similar to the other reported FDC tumours of the liver, our case of hepatic follicular dendritic cell tumour is also positive for Epstein-Barr virus, suggesting that the virus may play a role in its pathogenesis.

Adult↗
PubMed1998

Magnetic resonance imaging of lumbar vertebral apophyseal ring fractures.

Posterior lumbar vertebral apophyseal ring fractures are described in three adolescents presenting with severe low back pain, spinal tenderness and lower limb neurological deficit. Magnetic resonance imaging showed severe L4/5 posterior disc protrusion in all three patients. The actual fracture fragment was visualized with difficulty on MRI alone. The diagnosis of apophyseal ring fracture was made by either radiography or CT. Computed tomography delineated the size, shape and site of the fracture fragment. Surgical confirmation was obtained in all cases. Posterior lumbar vertebral apophyseal ring fractures may be difficult to visualize on MR imaging. Careful review of radiographs, supplemented by targeted CT, is necessary for the correct diagnosis and management of this entity.

Adolescent↗
PubMed1998

Transient bone marrow oedema: a variant pattern of sacral insufficiency fractures.

A 71-year-old woman presenting with severe low back pain was found to have a large oval area of increased sacral uptake on Tc-99m MDP scan, with corresponding T1-hypointense and T2-hyperintense areas on magnetic resonance (MR) images, highly suggestive of malignancy. Open biopsies showed only callus formation. The patient responded clinically to conservative measures, with twice-repeated follow-up Tc-99m MDP and MR scans documenting resolution of transient bone marrow oedema. We suggest that this form of marrow oedema represents a variant pattern of sacral insufficiency fractures.

Aged↗
PubMed1998

High-resolution computed tomography of bronchiolitis obliterans syndrome after bone marrow transplantation.

High-resolution computed tomography (HRCT) has been described to be useful in assessing bronchiolitis obliterans (BO) syndrome in the transplanted lung. Currently, BO syndrome is diagnosed if lung function deterioration shows persistent or progressive irreversible airflow obstruction, with FEV1 of less than 80% of baseline values, without clinical evidence of infection. The aim of this study is to assess the value of HRCT in evaluating BO syndrome after allogenic bone marrow transplantation (BMT). Fourteen HRCT scans were performed in 6 women and 3 men with moderately severe irreversible airflow obstruction and a clinical diagnosis of BO syndrome after BMT. Two patients had normal HRCT scans. In the remaining 7 patients, 7 of 11 HRCT scans were abnormal, with non-specific findings of bronchial dilatation (1), consolidation (2), hypoattenuated areas (4) and vascular attenuation (4). In comparison with the consistency of positive HRCT findings of BO syndrome in transplanted lungs, HRCT surveillance for BO syndrome in post-BMT patients with clinically established disease is of limited value, unless other pulmonary complications such as opportunistic infections are to be excluded.

Adult↗
PubMed1998

The magic angle phenomenon in tendons: effect of varying the MR echo time.

Increased signal intensity on magnetic resonance (MR) imaging of tendons arising from the magic angle phenomenon is well recognized. This study aimed to evaluate the effect of varying the echo time (TE) upon tendon signal intensity, and to determine if a modified TE value produces acceptable T1 and proton density (PD) weighted images. Fresh bovine tendons were imaged in a 1.5 T MR scanner using spin echo (SE) T1 and PD weighted sequences and utilizing a number of different coils. For each set of sequences, the tendon was orientated at 55 degrees to the main magnetic field (B0) and imaged using constant TR and incremental TE values. Signal intensity was measured on images at each TR/TE value and compared with the signal intensities of tendons orientated at 0 degree to B0, obtained using minimum TE values. This experiment was repeated with a 1.0 T MR scanner and utilizing a spine coil. The Achilles tendon of a human volunteer was similarly imaged using a general purpose flex coil. For bovine and human tendons orientated at 55 degrees to B0, the signal intensities decreased exponentially with increasing TE. A critical TE value exceeding 37 ms, for each sequence, reduced the signal intensities to the levels obtained with the tendons orientated at 0 degree to B0, such that the magic angle phenomenon could be avoided. Although there was variability of the signal intensities with different coils, the critical TE value remained constant and the anatomical clarity was not degraded. The critical TE value was unaltered using two MR scanners of different field strengths.

Achilles Tendon↗
PubMed1998

Spontaneous rupture of renal tumours: the role of imaging in diagnosis and management.

This study aimed to evaluate whether patients presenting with spontaneous haemorrhage from renal tumours could be accurately diagnosed and initially managed conservatively, and evaluate the role of imaging in guiding the timing and type of subsequent operation. The clinical features, imaging findings and management of seven patients presenting with spontaneous rupture of renal tumour over a 5-year period were reviewed. The information from various imaging studies was evaluated in relation to the subsequent course of intervention. The tumours consisted of six angiomyolipomas and one renal cell carcinoma. In all cases, imaging studies were diagnostic, with computed tomography being the most useful single modality. Emergency surgery was required in one patient for evacuation of suspected infected haematoma and wedge excision of angiomyolipoma. Three elective nephrectomies were performed, while three other patients with ruptured angiomyolipoma were treated conservatively and remained well, without any intervention. In conclusion, patients presenting with spontaneous rupture of renal tumour can be managed conservatively initially. Imaging facilitates accurate pre-operative diagnosis, which was angiomyolipoma in all but one patient in this series. The subsequent intervention can be tailored according to the lesion type and the anticipated risk of re-haemorrhage.

Adult↗
PubMed1998

Lumbar spine magnetic resonance imaging: comparison between fast spin echo proton density and spin echo T1 axial scans.

Spin echo (SE) T1 axial scans are routinely obtained in magnetic resonance imaging of the lumbar spine in many centres. This study directly compared matched SE T1 and fast SE (FSE) proton density (PD) axial scans. Both SE T1 and FSE PD axial scans of the lumbar spine were obtained in 116 consecutive patients. The imaging parameters (field-of-view, slice thickness, interslice gap, number of excitations and matrix size) and scan levels were identical for each pair of sequences. At two selected levels, L4/5 and L5/S1, various structures were independently graded by two observers. In 232 lumbar levels analysed, the bone marrow, epidural fat, disc, extradural nerve root and facet joint were equally well seen on both sequences by both observers (combined mean grades of 2.93-2.99). The thecal sac was marginally better depicted on FSE PD than on SE T1 images, with mean grades of 2.96 and 2.88, respectively. The psoas muscle was adequately visualized for diagnostic purposes on both sequences (mean grades of 2.30-2.32). The cauda equina were better seen on FSE PD (mean grade 1.92) than on SE T1 (mean grade 1.00) images. In conclusion, FSE PD scans are comparable to and may potentially replace SE T1 axial MR scans of the lumbar spine.

Humans↗
PubMed1997

Vacuum phenomena in the sacroiliac joints and in association with sacral insufficiency fractures. Incidence and significance.

STUDY DESIGN: The computed tomography scans of two groups of patients of similar age and sex, with and without sacral insufficiency fractures, respectively, were assessed retrospectively. OBJECTIVES: To determine the incidence of sacroiliac joint vacuum phenomena in individuals with and without sacral insufficiency fractures and to evaluate a possible association between vacuum phenomena and sacral insufficiency fractures. SUMMARY OF BACKGROUND DATA: The occurrence of vacuum phenomena is well recognized in the vertebra, but not in the sacroiliac joint. Gas foci in sacral insufficiency fractures recently has been reported. It has been suggested that the presence of vacuum phenomena may aid in the diagnosis of these fractures. METHODS: The computed tomography scans of 28 female patients with sacral insufficiency fractures and of 60 age- and sex-matched control individuals were evaluated. RESULTS: In the group with sacral insufficiency fractures, vacuum phenomena were detected in 69.2% of patients and in 63.5% of sacroiliac joints, with sacroiliac joint-related osteophytes found in 19.2% of patients. Very similar incidences were demonstrated in the control group. There was no correlation between sacroiliac joint osteophytes and vacuum phenomena in either group. The vacuum phenomenon was detected within the sacral insufficiency fracture in only one patient, in whom the fracture communicated with the adjacent sacroiliac joint. CONCLUSION: Vacuum phenomena are frequently found in the sacroiliac joints of elderly women, and their presence is of no diagnostic significance when demonstrated in patients with sacral insufficiency fractures.

Aged↗
PubMed1997

Systemic lupus erythematosus patients with respiratory symptoms: the value of HRCT.

Ten Chinese patients with systemic lupus erythematosus (SLE) and with persistent respiratory symptoms were evaluated with high resolution computed tomography (HRCT), chest radiographs and lung function tests. Fourteen of 15 HRCT scans performed were abnormal. The predominant disease pattern, seen in 60% of patients, was one of chronic interstitial lung disease with honeycombing, architectural distortion, parenchymal bands, pleural irregularity, and a lower zone predominance. Three of 10 patients had histological evidence of either lung fibrosis or interstitial pneumonitis. Airways disease and pleural thickening were seen in 20% and 87% of scans, respectively. Pleural thickening and honeycombing were present in 53% and 20% of chest radiographs, respectively. All concurrent lung function tests were abnormal. Reduced diffusion capacity of carbon monoxide (DLCO/VA) was observed in 60% of lung function tests. There was no correlation between duration of disease and DLCO/VA. However, pathological reduction of DLCO/VA was seen in 71% of patients with honeycombing, and 88% of patients with ground glass opacity. Our study has documented a high incidence of HRCT features of chronic lung destruction and a lower zone predominance in SLE patients with persistent respiratory symptoms.

Adult↗
PubMed1997

Arteriovenous shunting in hepatocellular carcinoma: its prevalence and clinical significance.

Arteriovenous shunting has been reported in hepatocellular carcinoma (HCC) and is a recognized contraindication to treatment by transcatheter arterial chemoembolization. This study aims to determine the prevalence of arteriovenous shunting in patients presenting with HCC and the development of shunts in those with inoperable HCC being treated with repeated chemoembolization. In a group of 292 Chinese patients (251 men, 41 women; mean age 54.7 years) presenting with HCC, hepatic angiograms demonstrated arteriovenous shunting in 91 cases (31.2%); shunting into the portal vein was observed in 84 (28.8%) and shunting into the hepatic vein in seven (2.4%). The hepatic angiograms of a separate group of 171 Chinese patients (144 men, 27 women: mean age 55.4 years) undergoing chemoembolization for inoperable HCC were analysed. Arteriovenous shunting developed during treatment in 20 patients (11.7%). Of these 20 patients, one had shunting into the hepatic vein while 19 (11.1%) had arterioportal shunting. Arteriovenous shunting occurred through the tumour or portal vein tumour thrombus in 13 patients, and occurred at sites remote from the tumour in the other seven patients. Shunting disappeared on repeat angiograms in three patients. Various postulated mechanisms responsible for arteriovenous shunting in HCC are reviewed. The recognition of development of arteriovenous shunting during chemoembolization of HCC is important as it has a direct bearing on patient management and prognosis.

Adolescent↗
PubMed1997

Childhood intussusception: ultrasound-guided Hartmann's solution hydrostatic reduction or barium enema reduction?

A comparison was made of the efficacy of ultrasound guided Hartmann's solution hydrostatic reduction on 23 patients (US group) with the same number of consecutive patients in whom hydrostatic reduction was done by barium enema (BE group) under fluoroscopy for childhood intussusception. The US group was diagnosed by ultrasound scan and reduction was attempted under the guidance of ultrasonography with Hartmann's solution at 100 mm Hg pressure. Excluded were patients older than 12 years, patients in shock, patients with peritonitis, bowel perforation, and gross abdominal distension as well as recurrent intussusception of more than three episodes. There were three patients excluded in this group. The diagnosis of intussusception and complete reduction were confirmed by gastrografin enema. This US group had three recurrences (3 of 26, 11.5%), one lead point (1 of 23, 4.4%), and 19 successful reductions (19 of 26, 73%). Incidentally, there were also three patients excluded in this period of barium enema reduction. There was only one recurrence (1 of 24, 4.2%), one leadpoint (1 of 23, 4.4%), and 12 successful reductions (12 of 24, 50%) in these 23 BE patients. The success rates for the ileo-colic intussusceptions with Hartmann's solution reduction and barium enema reduction were 91% (19 of 21) and 55% (12 of 22), respectively (P = .00865). There was no complication in either group, and the accuracy of diagnosing a complete reduction was 100% in both forms of reduction. Hence, ultrasound-guided hydrostatic reduction for childhood ileocolic intussusception is preferred because it is safe, accurate, has a higher success rate, and can avoid radiation exposure risk.

Barium Sulfate↗
PubMed1997

Bamboo skewer perforation of the bowel: computed tomography appearances.

A 25-year-old Chinese woman presented with a painful left-lower-quadrant abdominal mass. Computed tomography (CT) demonstrated a dense forked foreign body within an extraluminal mass. A 2.5 cm bamboo skewer surrounded by inflamed omentum was found at laparotomy. Different CT densities of bamboo skewers were obtained when exposed to air, water and 2% Gastrografin in an in vitro experiment. Awareness of the possible variations in appearances of wooden foreign bodies in and around the bowel may aid their CT diagnoses.

Abdominal Muscles↗
PubMed1997

Ileoileocolic intussusception in children: diagnosis and significance.

The ileoileocolic type of childhood intussusception is difficult to diagnose pre-operatively and is associated with increased morbidity. This study describes the clinical and imaging features of 10 consecutive ileoileocolic intussusceptions diagnosed ultrasonically in 10 patients over a 36 month period. Ultrasound-guided hydrostatic reduction using Hartmann's solution was attempted in all 10 patients. Clinical and imaging features were compared with those of 28 ileocolic intussusceptions in 25 patients diagnosed and treated using the same methods during the same period. Most of the clinical and plain radiographic features of the patients with the ileoileocolic and ileocolic types of intussusception were similar. The two types of intussusception had the classical doughnut or pseudokidney, or both, signs on pre-reduction ultrasound scans. During the reduction process, when surrounded by fluid within the caecal lumen, the ileoileocolic type of intussusception had a typical complex appearance due to frond-like loops of intussuscepted small bowel. This finding was present in all cases. The hydrostatic reduction rate was only 10% (1/10) for ileoileocolic intussusception, compared with 92.9% (26/28) for the ileocolic type. All unsuccessfully-reduced cases underwent surgery, with surgical confirmation of the intussusception type in all cases. Only one patient was found to have a lead point, caused by a Meckel's diverticulum. In conclusion, the diagnosis of ileoileocolic intussusception can be made pre-operatively and these patients require surgical management.

Child↗