Yiu-Wah Li

Solitary vertebral collapse: distinction between benign and malignant causes using MR patterns.

Differentiation of benign from malignant causes of vertebral compression fracture can be difficult at a single location. We studied 37 patients with solitary vertebral collapse (SVC) in the spine using magnetic resonance imaging (MRI). Sixteen of them were found to have a benign cause of SVC, while the remaining 21 were found to have malignancy. The following four MRI characteristics were investigated: ill‐ or well‐defined margin of the intravertebral lesion (P < 0.005); pedicle involvement (P < 0.05); MR enhancement pattern (P < 0.005); and paravertebral soft tissue lesion (PSL) (P < 0.025). It was found that cases of malignant SVC tended to have an ill‐defined margin, abnormal signal involvement of the pedicle, a marked and heterogenous MR enhancement pattern, and irregular nodular‐type PSL. Pedicle change with expansile lesion totally excluded a benign cause. By using these criteria, we were able to differentiate benign or malignant causes of SVC accurately.J. Magn. Reson. Imaging 1999;9:635–642.

Dysphagia in Patients with Nasopharyngeal Cancer After Radiation Therapy: A Videofluoroscopic Swallowing Study

This study evaluated swallowing status and the factors influencing swallowing in patients with nasopharyngeal carcinoma (NPC) after radiation therapy. During the period from July 1995 to June 1999, this cross-sectional study used videofluoroscopic swallowing study (VFSS) to evaluate 184 NPC patients who had completed radiation therapy [113 cases had completed radiation therapy ≤12 months prior to evaluation (acute group) and 71 cases had completed radiation therapy >12 months prior to evaluation (chronic group)]. The numbers of patients with tumors in each of the four stages were as follows: 24 in stage I, 45 in stage II, 41 in stage III, and 74 in stage IV. Swallowing abnormalities of the acute and chronic groups were correlated with multiple variables, including gender, age, the stage of the tumor, use of either neoadjuvant chemotherapy or radiosensitizer, and radiation modality. The analytical results indicated that the chronic group had a significantly higher proportion of swallowing abnormalities. Radiation modality, chemotherapy, and tumor staging were not significantly associated with swallowing dysfunction. Trend analysis revealed a progressive deterioration of most parameters of swallowing function in this group of patients. These findings indicate that swallowing function continues to deteriorate over time, even many years after radiation therapy in patients with NPC. Our results indicate that the time elapsed since radiation therapy correlates with the severity of dysphagia in NPC patients.

Usefulness of Electron Beam Computed Tomography in Children With Heterotaxy Syndrome

Children with heterotaxy syndrome frequently have complex cardiac and noncardiac malformations requiring detailed diagnostic evaluation for management planning. Direct delineation of these structures by electron beam computed tomography (EBCT) is validated as a means of diagnosis. From July 1995 to March 1997, 32 patients (16 girls, 16 boys) with clinically impressed heterotaxy syndrome were enrolled in this study. After evaluation by echocardiography, EBCT studies were performed. Interpretation of cardiac anomalies was performed by sequential analysis based on these cross-sectional images. The diagnoses were subsequently confirmed by angiocardiography and surgical findings. Twenty-eight patients had bilateral trifurcated bronchi, and most of these (24 of 28) did not have a spleen. Four patients had bilateral bifurcated bronchi, 2 patients had polysplenia, and the other 2 patients had a lobulated single spleen. We found that laterality could be identified by EBCT in all patients. Comparison of diagnostic yield between echocardiography, catheterization, and EBCT showed that EBCT is superior to echocardiography and catheterization in demonstration of pulmonary venous anatomy and presence of a very small rudimentary ventricle. In addition, associated visceral, bronchopulmonary, mediastinal, and intracardiac anomalies could all be clearly delineated by EBCT at the same time. Thus, EBCT is a promising complementary modality for an overall understanding of heterotaxy syndrome.

Spinal fractures and pseudoarthrosis complicating ankylosing spondylitis: MRI manifestation and clinical significance.

Purpose To analyze magnetic resonance (MR) patterns of fractures and pseudoarthrosis of the ankylosing spondylitic spine, and related changes in the dura and adjacent soft tissue. Materials and Methods Sixteen patients with radiographically evident fractures or pseudoarthrosis of the spine were included. Each underwent MR studies. Ten patients among them underwent surgical operations. Results Both transdiscal (n = 12) and transvertebral (n = 4) fractures were identified. The levels were located from T9 to L3. Five of 16 patients had pseudoarthrosis. The fractures or pseudoarthrosis had two patterns: low signal on T1-and high signal on T2-weighted images, and low signal on both T1-and T2-weighted images. Disruption of anterior longitudinal ligament (ALL) was identified in 14 patients. Seven patients had vertebral translation, all had disruption of the ALL. Dural adhesions were noted in five patients and manifested as linear epidural enhancements with triangular blunt edges. Conclusion MR patterns of ankylosing spondylitis are important in evaluating complications of fractures or pseudoarthrosis, as well as changes in dura, soft tissue, and ligaments.

DIAGNOSING THE COMBINATION OF RENAL DYSGENESIS, GARTNER'S DUCT CYST AND IPSILATERAL MULLERIAN DUCT OBSTRUCTION

PURPOSE We describe the differential points in the diagnosis of the combination of renal dysgenesis, Gartners duct cyst and ipsilateral müllerian duct obstruction. Various imaging studies and urological procedures were performed. We report our experience in detecting these anomalies in 10 girls and review the literature. MATERIALS AND METHODS Ten girls, 7 to 13 years old, with this combination of anomalies were identified in the last 10 years. Imaging studies as well as urological procedures were selectively performed, especially at puberty following menarche. Patients received long-term followup with ultrasound. RESULTS Cystic dilation of Gartners duct protruded into the bladder and presented as a ureterocele in 5 patients and posterior to the bladder in 5. Surgical removal of a partial portion of a Gartners duct cyst was performed in 5 patients for alleviation of urinary symptoms. Unilateral müllerian duct obstruction was demonstrated in all 10 patients. Excision of the vaginal septum was performed in 6 patients for relief of genital obstruction. CONCLUSIONS When cystic dilatation of the pelvis, especially a ureterocele-like cyst without ureteral dilatation, is found in girls with ipsilateral renal dysgenesis, the possibility of a Gartners duct cyst should be considered. For early detection and treatment of unilateral obstruction of duplicated müllerian ducts pelvic sonography should be performed at puberty, especially just after menarche, in girls with renal dysgenesis and ipsilateral Gartners duct cyst.

Three-dimensional reconstruction of abnormal ventriculoarterial relationship by electron beam CT

PURPOSE Assessment of the relationships of the ventricles and great vessels is critical in evaluating cardiac anomalies before surgery. We investigated the usefulness of 3D CT in their demonstration. METHOD From July 1995 through June 1996, 20 patients with abnormal ventriculoarterial relationships were analyzed by electron beam CT. A 3D gradient shading surface rendering was done on a workstation. We focused on the morphologies of the atria, ventricles, and great vessels and particularly their spatial relationships on the 3D images. RESULTS There were two cases of isolated ventricular inversion, three of anatomically corrected malposition, seven of congenitally corrected transposition, and eight of complete transposition. Anatomic presentations of 3D surface images in all were superior to cineangiography and echocardiography presentations and were consistent with intraoperative findings. CONCLUSION 3D CT images provide useful information that is not available by sectional or projective imaging. Independent segmental analysis of the anomalies by this method provides a complement for surgeons to understand the spatial relationships of the vessels and chambers of the heart, which may be of value in preoperative planning.

Usefulness of three-dimensional electron beam computed tomography for evaluating tracheobronchial anomalies in children with congenital heart disease☆

This study was undertaken to delineate tracheobronchial anomalies associated with congenital heart disease. From June 1995 to December 2000, 1,245 children with congenital heart disease underwent cardiac electron beam computed tomography with 3-dimensional reconstruction on an independent workstation. Tracheobronchial anomalies are strongly associated with congenital heart disease and accompanying tracheal stenosis is not uncommon. With 3-dimensional reconstruction, electron beam computed tomography provided excellent anatomic definition of the central tracheobronchial abnormalities.

Mesenteric lipoblastoma: case report.

Abstract. We present a rare case of mesenteric lipoblastoma in a 16-month-old girl. The US, CT and MRI features of this unusual tumour are described and correlated with the pathology findings. MRI more clearly suggested the presence of fat components in the tumour. In addition, multiplanar MR images demonstrated the anatomical extent better, which was essential for successful complete tumour excision.

The evaluation of false negative mammography from malignant and benign breast lesions

Preoperative mammograms from 395 breast cancers and 132 benign breast lesions were enrolled for this study. The false-negative (FN) rate for breast cancers from preoperative reading was 9.6% with 38 breast cancers missed on mammograms. The statistically significant differences occurred between true-positive (TP) and FN cancers for younger age (P<.025), smaller lesion size (P<.001), denser breast (P<.05), deep retroglandular location (P<.001). None of the FN cancers exhibited calcifications. The FN rate for mammography for benign breast lesions from preoperative reading was 18.9% with 25 lesions misdiagnosed. The statistically significant difference between benign TP and FN lesions occurred for central and subareolar location (P<.025). Exploration of possible factors and imaging features in FN mammograms can help reduce the FN rate for mammography.

Mature cystic teratoma of the pancreas in a child

A cystic pancreatic tumour is rare in a child and a mature cystic teratoma of the pancreas is even rarer. This is the first demonstration of the CT appearance of such a tumour in a child. We present a 2-year-old boy who presented with a palpable abdominal mass. Abdominal CT revealed a huge cystic mass in the upper abdomen. Pathology disclosed a mature cystic teratoma originating from the pancreas.