Publications by authors named "Margaret H Pui"

Background Neoadjuvant chemotherapy has made limb-salvage surgery possible for the patients with osteosarcoma. Diffusion-weighted magnetic resonance imaging (DWI) has been used to monitor chemotherapy response. Purpose To correlate the apparent diffusion coefficient (ADC) values with histopathology subtypes of osteosarcoma after neoadjuvant chemotherapy.

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Article Synopsis
  • The study aimed to compare two MRI techniques—dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI)—to effectively differentiate between stage T1 and T2 bladder urothelial carcinoma.
  • Fifty-nine patients with 92 tumors underwent MRI before surgery, with two uroradiologists interpreting the images independently, leading to categorization based on the presence of stalks or submucosal enhancement.
  • The combined interpretation of DWI and DCE-MRI increased diagnostic accuracy to 94.6%, highlighting that both imaging methods together provide better differentiation between the two cancer stages.
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To assess the diagnostic efficacy of diffusion-weighted MR imaging (DWI) for evaluating inflammatory activity in patients with Crohn's disease (CD). A total of 47 CD patients underwent MR enterography (MRE) and DWI using 3 b values of 50, 400, and 800 s/mm. Apparent diffusion coefficients (ADCs) of inflamed and normal bowel wall were calculated.

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OBJECTIVE. The purpose of this study was to determine an optimal multiparametric MRI protocol for characterizing tumors of low versus high grade and differentiating tumors as T1 versus T2 for preoperative staging of bladder urothelial carcinoma. SUBJECTS AND METHODS.

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Cryptococcus neoformans and Candida are common opportunistic pathogens of human. There is very limited literature on Cryptococcus neoformans cholangitis or Candida cholangitis in immunocompetent patient while mixed Cryptococcus neoformans and Candida cholangitis has not been reported in the literature ever before. We hereby report the imaging findings of a case of mixed Cryptococcus neoformans and Candida cholangitis in an immunocompetent boy.

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Purpose: To assess the feasibility of diffusion tensor imaging (DTI) of normal kidneys and the influence of hydration state.

Materials And Methods: Ten healthy volunteers underwent renal DTI after fasting for 12 hours and 4 hours, without fasting, and following water diuresis. Medullary and cortical apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values were measured and compared in the four different states of hydration.

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Objective: To investigate the relationship of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values with renal function on 3T diffusion tensor imaging (DTI) in chronic kidney disease.

Materials And Methods: Twenty healthy volunteers and 29 patients with CKD underwent DTI. The relationship among ADC, FA, and renal function was analyzed.

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Purpose: To investigate the efficacy of diffusion-weighted MRI (DWI) in differentiating recurrent tumor from chronic inflammation and fibrosis after cystectomy or transurethral resection of bladder cancer.

Methods: Eleven patients with suspected tumor recurrence underwent pelvic DWI and dynamic contrast-enhanced (DCE) MRI at 3 months to 7 years following bladder cancer resection. The diagnosis was histologically confirmed in all patients by transurethral or cystoscopic resection of 27 lesions within 2 weeks of MR examinations.

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Objective: The objective of this study was to assess the efficacy and clinical value of 64-slice computed tomography angiography (CTA) with image fusion for demonstrating the perigastric venous anatomy.

Methods: Twenty-six patients with gastric cancer underwent abdominal CTA examinations. Computed tomography angiography of stomach and perigastric veins and arteries were reconstructed and fused using volume-rendering technique.

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Objective: To evaluate the efficacy of discriminant function analysis of perirectal tumor infiltration with dynamic contrast-enhanced 64-detector row CT in rectal cancer.

Materials And Methods: Forty-nine patients with rectal cancer underwent dynamic contrast-enhanced CT. A total of 96 axial CT slices containing the tumors were evaluated.

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Objective: Pulmonary Kaposi's sarcoma (KS) occurs in more than 10% of patients with acquired immunodeficiency syndrome (AIDS) and has a high mortality rate. Prompt detection, diagnosis, and treatment reduce patient morbidity and mortality. The objective of this study was to determine the efficacy of 99mTc-hexakis-2-methoxy isobutyl isonitrile (99mTc-MIBI) imaging in detecting pulmonary AIDS-related KS.

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Background: Kapoksi's sarcoma (KS) is a common neoplasm complicating acquired immunodeficiency syndrome (AIDS). Skin, mucus membranes, lymph nodes, gastrointestinal tract and lungs may be involved. Kaposi's sarcoma has been demonstrated by scintigraphy, and a (99m)Tc-hexakis-2-methoxy isobutyl isonitrile (MIBI) scan can demonstrate lymphoma and tumors of the brain, nasopharynx, thyroid, parathyroid, lung, breast and kidney.

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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.

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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.

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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.

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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.

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Cerebral MR venography.

Clin Imaging

August 2004

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.

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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.

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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.

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