Bilateral congenital cystic adenomatoid malformation.
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Biomedical subjects
Publications and source records attributed to Jui-Sheng Hsu.
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It is important to differentiate malignant from benign gastric ulcers (GUs) because the early detection of malignancy offers the best prognosis and is essential for planning optimal therapy. However, the differential diagnosis between a malignant and benign gastric ulcer is sometimes difficult, and remains a great challenge. Recent advances in multidetector row-computed tomography (MDCT) with three-dimensional imaging software and multiplanar reformatted (MPR) images provide a potentially powerful tool for noninvasive gastric evaluation. Virtual gastroscopy (VG) is helpful in the detection and evaluation of GU in the same way as gastroscopy. In comparison with gastroscopy, VG images can depict abnormal endoluminal lesions with a wider field of view and they have no blind point because retrospective reconstruction is available. MPR images allow the radiologist to choose the optimal imaging plane to accurately evaluate the change of the gastric wall around the gastric ulcer avoiding partial volume averaging effects. This report describes the clinical usefulness of MDCT in differentiating malignant from benign GUs by using VG and MPR images.
PURPOSE: To prospectively investigate the apparent diffusion coefficient (ADC) and choline levels measured at hydrogen 1 ((1)H) magnetic resonance (MR) spectroscopy, to monitor therapeutic responses of hepatocellular carcinoma (HCC) to transcatheter arterial chemoembolization (TACE). MATERIALS AND METHODS: Institutional review board approval was obtained, and all patients and control subjects provided informed consent. Histologically proved large HCCs (>3 cm in diameter) were evaluated in 20 patients (16 men and four women; mean age, 59 years; range, 34-80 years) before TACE and 2-3 days after TACE. A control group of eight adults (five men and three women; mean age, 43 years; range, 24-76 years) with normal livers was examined by using the same protocol. Hepatic choline levels were measured by means of an external phantom replacement method, quantifying the peak at 3.2 ppm at (1)H MR spectroscopy. ADCs were measured for all lesions. A Wilcoxon rank sum test was used to compare absolute choline concentrations and ADCs at baseline between HCCs and normal liver parenchyma. Changes in choline levels and ADCs in the tumors before and after TACE were analyzed by using the Wilcoxon signed rank test. RESULTS: The median preoperative choline level in patients with HCC (measured in 18 of the 20 patients) was 4.0 mmol/L (range, 0.0-17.2 mmol/L), which was significantly higher than that in patients with normal livers (n = 8) (median, 1.6 mmol/L; range, 0.0-2.1 mmol/L; P < .01). Among 18 patients with HCC, choline levels decreased significantly from before TACE to after TACE (P < .01). A significant increase in ADC from before TACE to after TACE in the 20 patients with HCC was also found (P < .01). CONCLUSION: Hepatic choline levels and ADCs may allow monitoring of therapeutic responses of HCC to TACE although larger, more definitive and quantitative studies with clinical end points are needed.
RATIONALE AND OBJECTIVES: For computerized analysis of chest images in the clinical environment, identification of frontal (posteroanterior/anteroposterior) and lateral chest radiographs is an important preprocessing step. In this study, we developed a method to distinguish frontal from lateral views of the chest radiographs based on an analysis of the projection profile. MATERIALS AND METHODS: Projection profile is obtained by projecting a chest image on to the mediolateral axis. Two indices, body symmetry index and background percentage index, are computed from the projection profile. The combination of body symmetry index and background percentage index is used to determine the view of chest radiographs. The method is evaluated on a sample of 2000 frontal and 1000 lateral chest images. RESULTS: The values of body symmetry index are found to be 1.18 +/- 0.23 and 3.07 +/- 1.42 for frontal and lateral chest images, respectively. The values of background percentage index are found to be 0.03 +/- 0.05 and 0.33 +/- 0.09 for frontal and lateral chest images, respectively. The discrimination is evaluated by linear discriminant analysis and receiver operating characteristic analysis. Area Az under the receiver operating characteristic curve with the combination of the two indices is 0.993. CONCLUSION: The method can be used as a preprocessing step for further analysis in chest radiographs.
Mature teratomas are common neoplasms in the anterior mediastinum. However, a primary carcinoid tumor occurring in a mature teratoma is extremely rare. To our knowledge, there are only 2 published articles in the literature to date reporting a mature cystic teratoma of the mediastinum containing a carcinoid. We herein report another case of primary carcinoid tumor arising from a mature cystic teratoma in the anterior mediastinum.
Abnormalities in chest images often present as abnormal opacity or abnormal asymmetry. We have developed a novel method for automated detection of abnormalities in chest radiographs by use of these features. Our method is based on an analysis of the projection profile obtained by projecting the pixels data of a frontal chest image on to the mediolateral axis. Two indices, lung opacity index and lung symmetry index, are computed from the projection profile. Lung opacity index and lung symmetry index are then combined to detect gross abnormalities in chest radiographs. The values of lung opacity index are found to be 0.38 +/- 0.05 and 0.37 +/- 0.06 for normal right and left lung, respectively. The values of lung symmetry index are found to be 0.018 +/- 0.014 for normal chest images. The discrimination for the combination of the two indices is evaluated by linear discriminant analysis and receiver operating characteristic (ROC) analysis. Area Az under the ROC curve with the combination of the two indices in the classification of normal and abnormal chest images is 0.963.
A 50-year-old man presented with a middle and posterior mediastinal mass on chest radiograph and computed tomography. Surgical exploration revealed a large dumbbell-shaped lipomatous lesion. Histologic examination confirmed this to be a fibrolipoma. This is the first reported case of fibrolipoma in the mediastinum but outside of the esophagus.
BACKGROUND: Intraspinal clear-cell meningioma (CCM) is a rare morphological variant of meningioma with only 16 documented cases. We report one case and review the literature regarding intraspinal CCM. CASE PRESENTATION: A 2-year-old boy and a 2-month-old male infant presented with knee pain and leg weakness. Magnetic resonance imaging revealed an intradural extramedullary neoplasm at T10-L1. The patient underwent radical resection of the tumor. Pathology and immunohistochemical study demonstrated a CCM. Unfortunately, the patient had a recurrence 5 years after the operation. CONCLUSION: Intraspinal CCMs are very uncommon tumors. They usually show aggressive behavior with local recurrence observed in slightly more than half of all patients. We recommend serial imaging studies every 3 to 6 months during the first several years, after which an annual imaging study should be performed for follow-up.
PURPOSE: To evaluate the potential of a new lipophilic paramagnetic complex [Gd(Bz-TTDA)]2- [(4s)-4-benzyl-3,6,10-tri(carboxymethyl)-3,6,10-triazadodecandioic acid]2- designed for use as a hepatobiliary MR contrast agent. MATERIALS AND METHODS: MR imaging studies for normal and hepatocellular carcinoma (HCC) rat models were performed using a 1.5-T scanner. Sequential multislice T1-weighted turbo field echo (TFE) (TR/TE/flip angle: 15 msec/6.1 msec/25 degrees) coronal images of normal rats were obtained before and after intravenous injections of 0.1 mmol/kg [Gd(Bz-TTDA)]2- in study groups (N = 12) or 0.1 mmol/kg gadopentate dimeglumine (Gd-DTPA)2- in control groups (N = 12). Similar protocols of MR imaging with additional T2-weighted images were used for the rats with implanted HCC in both study and control groups (N = 12, in each group). MR images were analyzed to evaluate the time-enhancement change (% increase of signal-to-noise ratio [SI/N]) in normal liver, renal cortex, renal medulla, and tumors. The liver-lesion contrast-to-noise ratios (CNR) were also evaluated in study and control groups. The rats were killed immediately after the last MR scan to undergo autopsy and histopathologic observation. The acute toxicity test (medial lethal dose, LD50) in mice was also done. RESULTS: The liver enhancement in normal rats reached a plateau 5-50 minutes after injection of [Gd(Bz-TTDA)]2-, maintained for three hours, then gradually declined. Intensity of enhancement in liver, renal cortex, and medulla after injection of [Gd(Bz-TTDA)]2- was significantly higher than with Gd-DTPA. The efficacy of tumor characterization with injection of [Gd(Bz-TTDA)]2- was similar to that of Gd-DTPA at the early dynamic phase of the contrast study. However, the liver-lesion CNRs were significantly higher in the study group in the later phase, when tumor enhancement decreased and liver enhancement persisted. The dose of LD50 in acute toxicity test of [Gd(Bz-TTDA)]2- in mice was 7.5 mmol/kg. CONCLUSION: The preliminary results in this animal study indicated that [Gd(Bz-TTDA)]2- has the potential of becoming a reliable liver MR contrast agent.
OBJECTIVE: Diffusion-weighted imaging (DWI) is usually performed before administration of intravenous contrast agents. Repetition of DWI is occasionally necessary after contrast administration, but the effects of contrast material on DWI and apparent diffusion coefficient (ADC) values in the abdomen have not yet been fully examined. The purpose of this work is to assess whether administration of gadolinium-based contrast material significantly affects DWI and ADC values at the focal hepatic lesions. METHODS: The results of DWI at 3.0 T (Signa VH3; GE Medical Systems, Milwaukee, WI) were examined in 20 patients (age range: 33-86 years, mean age = 68 years) who were evaluated by means of a hepatic protocol at our hospital. Among the 20 patients studied, a total of 57 lesions were detected. Diffusion-weighted imaging was obtained using single-shot echo planar imaging with a b value of 500 s/mm. Patients were injected with 0.1 mmol/kg gadopentetate dimeglumine. The signal-to-noise ratio (SNR) of the liver and the hepatic lesions was examined, and the contrast-to-noise ratio (CNR) of each lesion was evaluated. In addition, the ADC values calculated from the DWI were compared before and after administration of contrast agent. The statistical significance of differences between precontrast and postcontrast administration was determined by use of a paired t test. RESULTS: The SNR and CNR of the DWI were not significantly different before and after administration of contrast agent. The ADC values tended to decrease after administration of contrast agent for each focal hepatic lesion and the liver, although they did not reach statistical significance. CONCLUSION: There was no significant difference before and after administration of contrast agent in the SNR or CNR of DWI. This indicates the feasibility of postcontrast DWI as a substitute for an unsuccessful precontrast-enhanced study in clinical practice.
BACKGROUND AND PURPOSE: In theory, ionic solutes diffuse more slowly in cartilage than do nonionic solutes. We tested the hypothesis that the contrast ratio between scar and recurrent disk fragment on MR images is greater after IV administration of an ionic rather than a nonionic contrast medium when a clinical dose is used. METHODS: Twenty patients who had recurrent lumbar disk herniation were enrolled in this study. The enhancement of epidural scar and recurrent disk fragment was measured at 5, 25, 40, and 50 min after IV injection of ionic and nonionic contrast media (0.1 mmol/kg) RESULTS: The enhancement was consistently and significantly higher for scar than for recurrent disk fragment, although the contrast ratio between scar and recurrent disk fragment decreased between 5 and 50 min after the administration of each contrast medium. No significant difference was shown between ionic and nonionic contrast media in the enhancement of recurrent disk fragment at 5, 25, 40, and 50 min after injection. The contrast ratio between scar and recurrent disk fragment was not a significant difference at 5, 25, and 40 min after administration of both contrast media. At 50 min, the contrast ratio between scar and recurrent disk fragment was 1.32 +/- 0.41 with ionic contrast medium and 1.20 +/- 0.56 with nonionic contrast medium. The difference was significant. CONCLUSION: The contrast ratio between scar and recurrent disk fragment is affected by the timing of the imaging. Images obtained immediately after the injection of each contrast medium showed a greater contrast ratio than did delayed images. In addition, with the ionic medium, this difference was greater than with nonionic medium at 5, 25, 40, and 50 min after injection and that difference reached statistical significance at 50 min.