Biomedical subjects

Margaret H Pui

Publications and source records attributed to Margaret H Pui.

7 recordsLinked to original sources

PubMed2005

Diffusion-weighted magnetic resonance imaging of spinal infection and malignancy.

BACKGROUND AND PURPOSE: Pyogenic and tuberculous spondylitis can mimic malignancy. The purpose of this study was to deter mine the efficacy of diffusion-weighted magnetic resonance imaging in differentiating spinal infection and malignancy. METHODS: Fifty-one consecutive patients with suspected spinal infection or malignancy were enrolled in the study. Apparent diffusion coefficients (ADCs) of paraspinal soft tissue mass and normal and abnormal vertebral bone marrow were determined on the diffusion-weighted magnetic resonance images of the spine. The mean ADCs of normal and abnormal vertebral bodies in patients with confirmed infection or malignancy were compared using nonparametric tests. RESULTS: ADCs of 69 tuberculous, 9 pyogenic, and 50 malignant vertebral marrow lesions were significantly higher than ADCs of normal marrow. ADCs of malignant bone marrow and 5 paraspinal soft tissue lesions were significantly lower than tuberculosis and pyogenic infection. There was no significant difference between the ADCs of 44 adult and 25 pediatric tuberculous bone lesions or between tuberculosis and pyogenic infection. Using the cutoff ADC of 1.02x10(-3)mm2/s for bone marrow, the sensitivity, specificity, and accuracy were 60.26%, 66.00%, and 62.50%, respectively, for distinguishing infection from malignancy. The sensitivity, specificity, and accuracy increased to 94.12%, 82.35%, and 90.20%, respectively, when the ADCs of associated soft tissue lesions were higher than 1.17x10(-3)mm2/s. CONCLUSIONS: Diffusion-weighted magnetic resonance imaging has limited usefulness for differentiating spinal infection and malignancy.

Adolescent↗

PubMed2004

Imaging diagnosis of congenital uterine malformation.

Congenital anomaly of the female reproductive system is associated with higher rate of infertility, spontaneous abortion, intrauterine growth retardation, premature birth and postpartum bleed. Because of the variable clinical pictures of obstruction of menstrual flow in adolescence to hypomenorrhea, vaginal discharge, dyspareunia, and fertility problems in adult life, early and accurate diagnosis is difficult. Complete uterine and vaginal septum can be easily confused with uterus didelphys. Management of these two müllerian duct anomalies is different. With improved treatment methods for complete relief of symptoms and prevention of further sequelae, comprehensive evaluation is important to identify the underlying problem and formulate appropriate therapeutic plan. The embryology, classification, and clinical presentation of uterine malformation, advantages and limitations of diagnostic methods including hysterosalpingogram, ultrasound, magnetic resonance imaging, laparoscopy, and hysteroscopy are discussed. The imaging features of different types of uterine anomalies are illustrated.

Adult↗

PubMedDate not supplied

Diffusion and magnetization transfer MRI of brain infarct, infection, and tumor in children.

The purpose of this study was to determine the efficacy of diffusion-weighted imaging (DWI) and magnetization transfer imaging (MTI) in the differential diagnosis of brain infarct, infection, hamartoma, and tumor in 106 children. The apparent diffusion coefficients (ADCs) and magnetization transfer ratios (MTRs) of the lesions were compared using nonparametric tests. There was an inverse relationship between ADC and MTR in subacute/chronic infarct, infection, hamartoma, arachnoid cyst, and tumor relative to normal brain parenchyma. Both ADC and MTR were reduced in acute infarct. DWI and MTI had a complementary role in the differential diagnosis of acute infarct from infection with lower MTR, from hamartoma with higher ADC, and from low-grade gliomas and benign tumors that had higher ADCs and lower MTRs. ADCs increased and MTRs decreased with the duration of infarct and lower tumor grade.

Adolescent↗

PubMedDate not supplied

Fatty tissue breast lesions.

Hamartoma, lipoma and fat necrosis are benign fatty tissue lesions that may present as breast lumps. The mammographic appearance may be distinctive allowing imaging diagnosis without biopsy. The characteristic feature of hamartoma is that of a compressible mass containing radiolucent fat interchanged with dense fibrous connective tissue surrounded by a thin radioopaque pseudocapsule. Lipomas are radiolucent with well-defined thin smooth capsule. Twenty-seven percent of fat necrosis appears as discrete round or oval radiolucent oil cyst with thin capsule and egg-shell calcification.

Adult↗

PubMedDate not supplied

Gadolinium-enhanced MR angiography of spinal arteriovenous malformation.

Patients with spinal arteriovenous malformation (AVM) have progressive or fluctuating neurological dysfunction because of hemorrhage, venous hypertension, vascular steal phenomenon, or mass effect from venous varicosity. Spinal AVM is classified into four types based on angiographic and operative findings. Conventional diagnostic methods include magnetic resonance imaging (MRI), supine myelogram, and angiogram. MRI can localize the vascular nidus in the cord, but it may sometimes be normal. Spinal angiogram is the definitive diagnostic modality. It is technically demanding and time consuming, requiring catheterization of all spinal vascular pedicles. MR angiography is fast and multiplanar, and it may shorten the duration of catheter angiography by demonstrating the level of feeders. Images of MRI, magnetic resonance angiography (MRA), and catheter angiogram are presented to illustrate the correlation and diagnosis of spinal AVM.

Adolescent↗

PubMedDate not supplied

MRI of gynecological neoplasm.

MRI is multiplanar, has large field of view, superior contrast resolution and no known adverse effect on the reproductive potential of ovaries. It is useful for characterizing solid, cystic or necrotic tissue, blood and fat. Contrast-enhanced MRI is also a comprehensive examination of the entire pelvis including lymph nodes, peritoneum, pelvic sidewalls, bone and muscles. It provides information about areas difficult to assess surgically, can refine staging classification, assists in planning surgery or radiotherapy and may be more cost-effective by limiting use of surgery. This is a pictorial essay of MRI assessment of female pelvic neoplasm.

Contrast Media↗

PubMedDate not supplied

Cerebral MR venography.

This paper illustrates the technique and clinical use of cerebral MR venography (MRV). Dural sinus thrombosis is detected by both two-dimensional time-of-flight (TOF) and three-dimensional phase-contrast (PC) techniques. Venous angiomas are demonstrated by the three-dimensional PC method. The arterial feeders, nidus and draining veins of cerebral arteriovenous malformation (AVM) can be visualized on contrast-enhanced TOF three-dimensional MR angiogram. The high-flow draining veins of cerebral and dural AVMs, vein of Galen malformation and carotid cavernous fistula are better seen on contrast-enhanced three-dimensional gradient-echo MRV.

Carotid-Cavernous Sinus Fistula↗