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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
PubMed2001

Imaging of finger joints in a whole-body MR system using a simple and low-cost solenoidal coil.

This work considers the design and operation of a solenoid radiofrequency (RF) coil for magnetic resonance (MR) mini-imaging of finger joints using a whole-body system. The considerations were focused on the requirements of high sensitivity, easy patient access, and cost-effectiveness. The proposed design is a short, two-turn solenoidal coil that accomplishes high spatial uniformity over a 2-cm region of interest (ROI). The coil resembles an oversized ring, and easily fits fingers that are spread. An experimental demonstration of the proposed approach is given by imaging the proximal interphalangeal joint in healthy volunteers using a 2.5-cm field of view (FOV). Spin-echo and gradient-recalled-echo T1-weighted sequences, and a 3D spoiled-gradient-echo sequence were used.

Cost-Benefit Analysis↗
PubMed2001

Artifacts in musculoskeletal magnetic resonance imaging: identification and correction.

A large number of artifacts occur in magnetic resonance (MR) imaging of the musculoskeletal system. These artifacts may potentially affect the quality of MR images, and may also simulate pathologic conditions and produce pitfalls in interpretation. Motion artifacts may be periodic or random. Protocol-error artifacts include saturation, wraparound, radiofrequency (RF) interference, shading, and partial volume averaging artifacts. Truncation artifacts occur when the number of phase-encoding steps of high spatial frequencies is insufficient (or under-sampled) for faithful reproduction of the true anatomic detail of the original image. Chemical shift artifacts are due to the protons in fat being mismapped relative to water protons. Susceptibility artifacts occur at the interfaces of structures with different magnetic susceptibilities. Artifacts special to the musculoskeletal system include the magnic angle phenomenon and spurious signal induced at very short echo times, both of which affect anisotropic structures such as tendon, ligament, and cartilage. Recognition and, if possible, correction of these artifacts are an important aspect of practical musculoskeletal MR imaging.

Artifacts↗
PubMed2001

Effect of Sandostatin LAR on sleep apnoea in acromegaly: correlation with computerized tomographic cephalometry and hormonal activity.

OBJECTIVES: Sleep apnoea has been reported to occur in subjects with acromegaly. This study evaluates the relationship among biochemical activity, sleep apnoeic activity and upper airway anatomic profile in acromegaly, and the effect of Sandostatin LAR, a long-acting somatostatin analogue, on these parameters. PATIENTS: Fourteen subjects with acromegaly were recruited. MEASUREMENTS: Subjects were assessed at baseline and those with apnoea-hypopnoea index (AHI) > or = 5 were reassessed after 6 months of treatment with Sandostatin LAR 20-30 mg IMI 4-weekly. Biochemical activity was assessed with levels of GH and IGF-1. Sleep disordered breathing was assessed with overnight polysomnography. Upper airway anatomic profile was defined with computerized tomographic cephalometry. RESULTS: Of 14 subjects (age 42.0 +/- 8.1 years, mean +/- SD; 11 men) at baseline, there was a positive correlation between GH and tongue length (VT; P = 0.004), and between AHI and cephalometric indices: length of soft palate (PMU; P = 0.002); mandibular plane-hyoid bone distance (MPH; P = 0.017), maximum thickness of soft palate (Max-SP; P = 0.018) and VT (P = 0.027). Eight patients had sleep disordered breathing (AHI > or = 5) which was predominantly obstructive in nature (AHI = 29.4 +/- 22.6). After treatment, there were significant improvements in hormonal profile: GH, mU/l (before, 51.5 +/- 27.8; after, 8.0 +/- 7.4; P = 0.017) and IGF-1, nmol/l (before, 95.5 +/- 23.4; after, 35.0 +/- 12.4; P = 0.012); sleep-disordered breathing: AHI (before, 29.4 +/- 22.6; after, 13.4 +/- 11.12; P = 0.025), snoring episodes (before, 486 +/- 240; after, 165 +/- 170; P = 0.05); cephalometric indices, mm: MPH (before, 18.8 +/- 12.1; after, 14.8 +/- 8.4; P = 0.018), VT (before, 72.3 +/- 4.4; after, 69.7 +/- 4.3; P = 0.05). There was a positive correlation between the reduction in GH and AHI (r = 0.738, P = 0.037). CONCLUSIONS: The findings demonstrated that there was correlation between sleep apnoea severity and soft tissue overgrowth at the upper airway region in acromegaly. They also suggest that Sandostatin LAR improved obstructive sleep apnoea in acromegaly, and the effect might be partly mediated via a reduction in upper airway soft tissue, in particular that of the tongue, concomitant with a reduction in GH levels.

Acromegaly↗
PubMed2001

Giant cell tumour of the tendon sheath of the hand: a pictorial essay.

Giant cell tumour of the tendon sheath is a soft tissue mass found occasionally in the hand. Its diagnosis can be readily made preoperatively if the characteristic MRI features are appreciated. This pictorial essay demonstrates and describes the imaging findings correlated with histopathological findings in a group of patients with proven giant cell tumour of the tendon sheath.

Adult↗
PubMed2001

Multiple bilateral giant fibroadenomas associated with cyclosporine A therapy in a renal transplant recipient.

A 31-year-old woman developed a right breast mass following cyclosporine A therapy after a renal transplant. Several large breast masses continued to grow bilaterally. Mammography and ultrasonography showed features of giant fibroadenomas. The diagnosis was confirmed by biopsy of one of the masses. Awareness of the association between cyclosporine A therapy and fibroadenoma development in renal transplant recipients is highlighted.

Adult↗
PubMed2001

Growing wrist mass.

A 46 year old man presented with a growing mass over his wrist. Erosions of the triquetrum and hamate were present radiographically. Magnetic resonance imaging (MRI) showed a solid mass arising from the extensor carpi ulnaris tendon, which was T(1) hypointense and isointense, T(2) hypointense, and bloomed on gradient echo images. The preoperative diagnosis of giant cell tumour of the tendon sheath was confirmed on histopathological examination of the excised specimen. The clinical, pathological, and imaging features, with emphasis on MRI findings, of this condition are reviewed.

Diagnosis, Differential↗
PubMed2001

Percutaneous vertebroplasty: a new technique for treatment of painful compression fractures.

Vertebroplasty is an effective technique in which polymethyl methacrylate, a surgical cement, is injected into a vertebral body. This technique provides increased strength and pain relief in vertebrae weakened by osseous lesions as metastases, multiple myeloma, and aggressive hemangiomas, and from osteoporotic fractures. Infrequent serious complications are mainly related to polymethyl methacrylate leakage into the spinal canal and around vital soft tissue structures. Complications are decreased by careful fluoroscopic guidance and meticulous radiological technique. Indications should be dictated by a multidisciplinary team approach.

Back Pain↗
PubMed2001

Clinics in diagnostic imaging (60). Insufficiency fractures of the pelvis.

An 80-year-old woman presented with severe low back pain of gradual onset. Her walking ability was affected. Physical examination was essentially negative. Bone scintiscans showed a butterfly-shaped area of increased sacral uptake as well as focal pubic uptake. The diagnosis of sacral and parasymphyseal insufficiency fractures was confirmed by CT. The patient recovered well with conservative management. The clinical and imaging features, and management of insufficiency fractures of the pelvis are discussed.

Aged↗
PubMed2001

Tophaceous gout.

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Aged↗