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Yung-Liang Wan

Publications and source records attributed to Yung-Liang Wan.

At least 37 records · Page 2Linked to original sources
PubMed2004

Eight cases of severe acute respiratory syndrome presenting as round pneumonia.

OBJECTIVE: The purpose of this study was to describe the radiographic findings and evolution of round pneumonia found in eight patients with confirmed severe acute respiratory syndrome (SARS). CONCLUSION: SARS may present as round pneumonia on chest radiographs initially or during the treatment course. It may remain unchanged for up to 9 days before evolution to ill-defined air-space opacities. Radiologists and physicians should consider the possibility of "SARS pneumonia" when spherical air-space opacities are noted on chest radiographs of febrile patients.

Adolescent↗
PubMed2004

Ultrasonography-guided core-needle biopsy of parotid gland masses.

BACKGROUND AND PURPOSE: An accurate diagnosis of a parotid gland mass is essential for adequate management. We determined the clinical efficacy of USCNB in diagnosing parotid gland masses by using cutting needles of different bores. METHODS: We reviewed records for 40 benign and 13 malignant parotid lesions. USCNB was performed by using 14-20-gauge needles (mean, 16.6 gauge) with one to five (mean, 2.43) passes and a 15-mm throw or specimen notch. Final diagnoses were established on the basis of surgicopathologic results in 31 cases, and on the basis of histopathologic analysis of biopsy specimens, clinical data, and/or imaging studies in 22, with a follow-up of 12.2-77.5 months (mean, 33.6 months). RESULTS: Compared with surgicopathology, USCNB had a sensitivity of 83%, a specificity of 100%, and an accuracy of 97% in providing specific tissue diagnoses and in differentiating malignant from benign masses. Its positive and negative predictive values were 100% and 96%, respectively, in diagnosing malignancy. One patient (2%) had a local hematoma without sequela after surgical removal of a Warthin tumor. Core biopsy results were completely concordant with surgical findings in 30 (97%) of 31 cases. CONCLUSION: USCNB is a safe and efficient diagnostic procedure with an accuracy of 97% in the pathologic diagnosis of parotid masses. It can be performed in an outpatient clinic and enables specific tissue diagnosis to obviate intraoperative frozen biopsy and unnecessary surgery. An 18-gauge needle is sufficient for accurate and specific tissue diagnosis of parotid masses.

Adolescent↗
PubMed2003

Functional MRI of amblyopia before and after levodopa.

Functional magnetic resonance imaging (fMRI) was applied to five older amblyopes with monocular amblyopia before and after levodopa treatment. During the experiment, images were acquired in two runs with visual stimulation delivered through the sound and the amblyopic eyes, respectively. The experiment was performed on each of the subjects, before and after their oral administration of levodopa/carbidopa (0.5/0.12 mg/kg) three times per day for 7 weeks. Our study demonstrated that there was no effect on the spatial extent of the visual cortical activation during the sound eye stimulation (P=0.17), but some improvement during the amblyopic eye stimulation (P=0.06). The volume ratio between the amblyopic and sound eye stimulation significantly increased after the treatment (P<0.05). This finding supports the previous studies of levodopa effect on amblyopia at the visual cortical level, and suggests that fMRI can be a useful tool in assessing changes of visual cortical activity after the treatment

Adolescent↗
PubMed2003

Correlation of dynamic contrast enhancement MRI parameters with microvessel density and VEGF for assessment of angiogenesis in breast cancer.

PURPOSE: To investigate the association between parameters obtained from dynamic contrast enhanced MRI (DCE-MRI) of breast cancer using different analysis approaches, as well as their correlation with angiogenesis biomarkers (vascular endothelial growth factor and vessel density). MATERIALS AND METHODS: DCE-MRI results were obtained from 105 patients with breast cancer (108 lesions). Three analysis methods were applied: 1) whole tumor analysis, 2) regional hot-spot analysis, and 3) intratumor pixel-by-pixel analysis. Early enhancement intensities and fitted pharmacokinetic parameters were studied. Paraffin blocks of 71 surgically resected specimens were analyzed by immunohistochemical staining to measure microvessel counts (with CD31) and vascular endothelial growth factor (VEGF) expression levels. RESULTS: MRI parameters obtained from the three analysis methods showed significant correlations (P < 0.0001), but a substantial dispersion from the linear regression line was noted (r = 0.72-0.97). The entire region of interest (ROI) vs. pixel population analyses had a significantly higher association compared to the entire ROI vs. hot-spot analyses. Cancer specimens with high VEGF expression had significantly higher CD31 microvessel densities than did specimens with low VEGF levels (P < 0.005). No significant association was found between MRI parameters obtained from the three analysis strategies and IHC based measurements of angiogenesis. CONCLUSION: A consistent analysis strategy was important in the DCE-MRI study. In this series, none of these strategies yielded results for MRI based quantitation of tumor vascularity that were associated with IHC based measurements. Therefore, different analyses could not account for the lack of association.

Breast↗
PubMed2002

Small bowel intussusception in symptomatic pediatric patients: experiences with 19 surgically proven cases.

Nineteen cases of surgically proven symptomatic pediatric small bowel intussusceptions (SBI) were retrospectively reviewed. Clinical presentations included vomiting (89.5%), abdominal pain and/or irritable crying (89.5%), fever (52.6%), bloody stools (26.3%), palpable abdominal masses (15.8%), hematemesis (10.5%), jaundice (5.3%), and seizures (5.3%). The duration between symptom onset and hospitalization ranged between 20 and 336 hours (average 75.8 hours). Two patients with suspected appendicitis and small bowel obstruction were operated on promptly. Sonograms revealed target lesions (average diameter 2.9 cm) suggestive of intussusception in 13 out of 17 patients, with 10 lesions located in the paraumbilical or left abdominal regions. Barium enemas in 12 of these 13 patients demonstrated no colonic lesions. Diagnosis and surgery were delayed in 16 patients (average delay = 32 hours). The remaining 1 patient with positive sonographic findings underwent early surgery after computed tomographic (CT) confirmation of SBI. Surgery revealed ileoileal intussusceptions in 11 patients, jejunojejunal in 4, jejunoileal in 3, and duodenojejunal in 1. Eight patients had lead points. Bowel complications (ischemia, necrosis, or perforation) occurred in 8 patients. The duration between symptom onset and surgery in patients with bowel complications was significantly longer than for patients without complications (p = 0.0026). In conclusion, delayed diagnosis and surgical treatment in symptomatic pediatric patients with SBI were common, leading to a high rate (42%) of bowel complications. Sonographic demonstration of a 2-3 cm target lesion, especially if paraumbilical or left abdominal, is suggestive of SBI and may obviate the need for a barium enema; however, CT is helpful for confirming SBI. In symptomatic SBI, once diagnosed, early surgical referral is strongly recommended.

Adolescent↗
PubMed2002

Functional anatomy of syntactic and semantic processing in language comprehension.

A functional magnetic resonance imaging (fMRI) study was conducted to map syntactic and semantic processes onto the brain. Chinese-English bilingual subjects performed two experimental tasks: a syntactic plausibility judgment task in which they decided whether a viewed verb phrase was syntactically legal, and a semantic plausibility judgment task in which they decided whether a viewed phrase was semantically acceptable. A font size judgment task was used as baseline. It is found that a large-scale distributed neural network covering the left mid-inferior frontal and mid-superior temporal cortices was responsible for the processing of Chinese phrases. The right homologue areas of these left cortical sites were also active, although the brain activity was obviously left-lateralized. Unlike previous research with monolingual English speakers that showed that distinct brain regions mediate syntactic and semantic processing of English, the cortical sites contributing to syntactic analysis of Chinese phrases coincided with the cortical sites relevant to semantic analysis. Stronger brain activity, however, was seen in the left middle frontal cortex for syntactic processing (relative to semantic processing), whereas for semantic processing stronger cortical activations were shown in the left inferior prefrontal cortex and the left mid-superior temporal gyri. The overall pattern of results indicates that syntactic processing is less independent in reading Chinese. This is attributable to the linguistic nature of the Chinese language that semantics and syntax are not always clearly demarcated. Equally interesting, we discovered that when our bilingual subjects performed syntactic and semantic acceptability judgments of English phrases, they applied the cerebral systems underlying Chinese reading to the processing of English.

Adult↗
PubMed2002

Formation of independently revascularized bowel segments using the rectus abdominis muscle flap: a rat model for jejunal prefabrication.

Reconstruction of the pharyngoesophagus with free jejunal transfer is a major challenge when recipient neck vessels are absent because of previous surgery or irradiation. In such instances, jejunal transfer using a muscle flap as a "vascular carrier" may be a problem-solving alternative. Pretransfer vascularization of the jejunum is achieved by wrapping the muscle flap around the small bowel segment. After a short staging period, the mesenteric pedicle is divided and the bowel segment is transferred up to the neck based on its new blood supply. The objectives of this study were to develop an animal model for prefabricating independently revascularized jejunal segments using the rectus abdominis muscle flap and to determine the minimal time required for independent bowel survival. Twenty-four mature (500-g to 700-g) rats were divided into six experimental groups of four animals each. In each animal, a 1.5-cm segment of proximal jejunum was isolated on two jejunal arteries and wrapped with a superior pedicled rectus abdominis muscle flap. To determine the time of neovascular takeover, the mesenteric pedicles were ligated on postoperative day 2 (group I), day 3 (group II), day 4 (group III), day 5 (group IV), day 6 (group V), and day 7 (group VI). At the time of pedicle ligation, the composite flap was transposed to a new subcutaneous position. Viability of bowel was assessed according to gross appearance and histologic examination 48 hours after transfer. Complete survival of revascularized jejunum in 11 of 12 animals was obtained after pedicle ligation on postoperative day 5 and beyond (p < 0.0001, Fisher's exact test). These bowel segments demonstrated luminal patency, intact pink mucosa, mucus production, and visible peristalsis. Histologic examination showed healthy intestinal epithelium and tissue integration along the serosa-muscle interphase. In contrast, pedicle ligation on day 4 and earlier resulted in varying degrees of bowel necrosis characterized by flattening or ulceration of mucosa (day 4), mucosal sloughing and necrosis of mural musculature (day 3), and complete loss of bowel architecture with lumen obliteration (day 2). These findings suggest that jejunal segments may be independently revascularized with the rectus abdominis muscle flap in the rat model. Complete survival and gross normal bowel function may be obtained without mesenteric perfusion after a minimal time of 5 days.

Abdominal Muscles↗
PubMed2002

Helical computed tomography of the abdomen: evaluation of image quality using 1.0, 1.3, and 1.5 pitches.

BACKGROUND: The purpose of this study was to investigate whether trained radiologists can distinguish minor differences among computed tomography (CT) images of extended helical pitches of 1.0 to 1.5. METHODS: Between September 2000 and February 2001, 72 patients were randomized into 1 of 3 equal groups: helical pitches of 1.0, 1.3, and 1.5. The imaging parameters of all patients were kept constant. Twelve of the 72 patients were excluded because of various pathological conditions. In a total, 60 examinations were enrolled in the evaluation study. Three radiologists blinded to the image parameters were asked to independently evaluate 9 normal structures and overall images of 60 studies using a scale from 1 (worst) to 5 (best). RESULTS: There were no statistically significant differences in evaluation of image quality among helical pitches 1.0, 1.3, and 1.5 of abdominal CT when assessing 9 normal structures and overall images independently (p > 0.05). CONCLUSIONS: Abdominal CT performed with helical pitches of 1.0, 1.3, and 1.5 were equivalent in this study. With the use of a helical pitch greater than 1, clinicians can benefit from increased scan coverage in less time and with less radiation than can be achieved with standard helical pitch-1.0 protocols.

Adult↗
PubMedDate not supplied

Sonographic evaluation of mammographically detected microcalcifications without a mass prior to stereotactic core needle biopsy.

PURPOSE: The purpose of this prospective study was to evaluate the clinical usefulness of sonographically re-evaluating areas of microcalcification found mammographically before undertaking stereotactic core needle biopsy (SCNB). METHODS: Patients with nonpalpable breast lesions appearing as microcalcifications on mammograms and who had been referred to us for SCNB were re-evaluated sonographically before the procedure. None of the breast lesions had been associated with a density on the mammograms, and the initial sonographic evaluations had been negative. Using the mammograms for correlation, we meticulously re-evaluated the areas of microcalcifications sonographically using a high-frequency linear-array transducer. The sonographic and histopathologic results were then reviewed and correlated. The sonographic findings and visibility of the mammographically detected microcalcifications were analyzed by the 2-tailed Fisher's exact test and the chi-square test. RESULTS: Sixty-six patients, who had 68 cases of microcalcifications, were enrolled. Thirteen of the 66 patients underwent surgery, and 9 of the 13 were found to have breast carcinoma. In the sonographic re-evaluation before SCNB in these 9 patients, an associated soft tissue mass was demonstrated in 5 patients but not in the other 4. Sonographic re-evaluation also revealed abnormalities in 24 of 68 cases (35.3%), in contrast to the negative findings on the initial sonography. Using the chi-square test to identify a trend, we found that the percentage of cases that were sonographically visible was highest for clustered benign microcalcifications and lowest for segmental benign microcalcifications (p < 0.0001). CONCLUSIONS: In breast lesions that appear as microcalcifications without an associated mass on mammograms, pre-SCNB sonographic re-evaluation with a high-frequency transducer can depict microcalcifications, particularly the clustered ones, and can detect small associated masses. Although the absence of a sonographically detectable mass in areas of mammographically detected microcalcifications does not guarantee the absence of cancer, the presence of an associated mass on sonography should warrant close follow-up in the case of negative results to avoid a delay in the diagnosis of breast carcinoma.

Adult↗
PubMedDate not supplied

Symptomatic mesentery Castleman disease mimicking a pancreatic tumor.

Castleman disease (CD) is an uncommon lymphoproliferative disorder of unknown etiology. It can be localized or multicentric. There are two major histological variants. The hyaline-vascular type predominates in the thorax and the mesenteric disease is usually of the plasma cell type. Hyaline-vascular CD of the mesentery is very rare. We report such a neoplasm of mesenteric root in a 38-year-old woman who presented with abdominal discomfort. Dynamic magnetic resonance imaging (MRI) of CD has rarely been reported previously. The imaging findings of CD on computed tomograms, MR images and angiograms were described.

Adult↗
PubMedDate not supplied

Imaging findings of retroperitoneal lymphangiomyomatosis in a patient with lymphoma.

A 31-year-old female with lymphoma was incidentally found to have a left retroperitoneal lymphangiomyomatosis (LAM). The tumor was proved by pathology and immunohistochemical study of the tissue specimen obtained by ultrasound-guided core needle biopsy. The characteristic sonographic, computed tomographic, magnetic resonance imaging, and positron emission tomographic (PET) features of this unusual lesion were described. It was managed conservatively and remained stable on 2-year follow-up study. LAM should be considered in the differential diagnoses in cases of a retroperitoneal solid mass with cystic components.

Adult↗
PubMedDate not supplied

Diagnosis and staging of gallbladder carcinoma. Evaluation with dynamic MR imaging.

The purpose of this study is to determine the ability of dynamic magnetic resonance imaging (MRI) in the diagnosis and staging of gallbladder cancer (GBC). Images of dynamic MRI of hepatobiliary system combined with MR cholangiography (MRC) of 18 patients with pathologically proved gallbladder cancer were correlated with pathological and operative findings. Focal or diffuse wall thickening was present in 10 patients. In five patients, the tumor appeared as a fungating or intramural mass. A tumor replacing the gallbladder was found in two patients and a small cancer in cystic duct in one patient. The tumor featured early and irregular enhancement, which persisted throughout the dynamic study. Metastatic nodes were found by surgicopathology in 13 patients and were depicted by the dynamic MRI in 11 patients. Local invasion to liver was found by surgery in 12 patients and correctly detected by MRI in 11 patients. MRI detected duodenum invasion in three out of six patients and none of the three cases with omental metastasis. In conclusion, dynamic MRI is useful and reliable in staging of advanced gallbladder cancer. MRI combined with MRC is sensitive in detection of obstructive jaundice, liver invasion as well as liver and lymph nodes metastasis. It is more difficult to delineate the invasion to duodenum and omental metastasis by MRI.

Aged↗
PubMedDate not supplied

Clinically occult isolated right iliac mycotic aneurysm with duodenal involvement in a diabetic elderly man: multislice CT diagnosis.

A diabetic old man presented with vague abdominal discomfort and intermittent tarry stools for 2 days and gastric ulcers with bleeding was diagnosed after endoscopy. Multislice computed tomography (MSCT) clearly depicted an isolated right iliac mycotic aneurysm with retroperitoneal extension and duodenal involvement. Timely operation and effective antibiotic treatment resulted in complete recovery. To our knowledge, this is the first report of an isolated mycotic iliac artery aneurysm (IAA) complicated with an aneurysmo-duodenal fistula induced by Klebsiella pneumoniae.

Abdominal Pain↗
PubMedDate not supplied

Imaging features of atypical thoracic Castleman disease.

The imaging features of 16 cases of pathologically proven atypical thoracic Castleman disease (CD) were retrospectively reviewed. Thirteen out of 16 tumors originated from atypical locations, including eight from the pleura and one each from the axilla, supraclavicular fossa, intercostal space, pericardium, and lung. Six out of 16 tumors revealed atypical enhancement, including poor CT enhancement in three tumors, target-like CT enhancement in two tumors, and concentric MR enhancement pattern in one tumor. These atypical enhancement patterns were histopathologically corresponded to various degrees of degeneration, necrosis, and fibrosis.

Adult↗
PubMedDate not supplied

Sudden cardiac arrest during computed tomography examination: clinical findings and "dense abdominal veins" on computed tomography.

We report imaging findings in five patients who had sudden cardiac arrest during contrast-enhanced computed tomography (CT). We observed strikingly dense abdominal veins, variable degrees of arterial enhancement, and poor abdominal visceral enhancement. Comparison with a control group of 30 patients revealed a statistically significant increase in mean enhancement of the abdominal veins (including the inferior vena cava, bilateral renal veins, and major tributaries of the hepatic vein) (Kruskal-Wallis test, P< 0.05). These patients lacked any clear cause of cardiac arrest, and the arrest may have been related to an adverse reaction to contrast medium. Despite resuscitation, two patients died and three convalesced. In summary, sudden cardiac arrest is characterized by "dense abdominal veins" on CT in the absence of the cardiac pump function. This effect was presumably the result of forced reflux and stagnation of contrast medium in the abdominal veins without any dilution with the circulating blood, leading to a markedly dense appearance of these venous structures.

Abdomen↗