Search PubMed⌕ Search

Biomedical subjects

C M Tiu

Publications and source records attributed to C M Tiu.

At least 19 recordsLinked to original sources
PubMed2007

Topoisomerase 2alpha plays a pivotal role in the tumor biology of stage IV thymic neoplasia.

BACKGROUND: Microsatellite studies in histologic types B3 and C thymic neoplasia detected gains on chromosome 17q, which contains the Her-2/neu and its juxtaposed topoisomerase 2alpha (T2alpha) genes. The study aimed to evaluate their impact on tumor biology and survival of advanced thymic neoplasia patients. METHODS: From 1991 to 2005, 36 consecutive stage IV thymic carcinoma patients were treated, 18 men and 18 women, aged 11 to 84 years. There were 22 thymic carcinoma, 13 type B3, and 1 type B2 thymoma. Patients received treatment consisting of surgical resection, combination chemotherapy with the CAP (cyclophosphamide, Adriamycin, cisplatin) regimen, or radiation therapy potentiated by high-dose weekly 5-fluorouracil infusion. Permutations of these 3 treatment modalities were prescribed as necessary. RESULTS: T2alpha gene amplification was detected in 4 of 14 thymic carcinoma and 1 of 15 type B3 thymoma. Three thymic carcinoma patients had Her-2/neu coamplification and these 3 patients had rapidly growing tumor and extensive disease at initial diagnosis. CAP was prescribed in 28 patients and 20 patients responded (response rate, 71.4%, 95% confidence interval [CI]: 52.8% to 85%); all responders overexpressed (> or = 10% nuclei positive) the T2alpha protein, whereas 4 nonresponders had very low expression. T2alpha overexpression predicts CAP response, and its absence predicts resistance (P = .001). Overall survival was significantly prolonged if the tumor was resectable (P = .001), of type B3 histology (P = .0039), and had no Her-2 gene amplification (P = .0081). CONCLUSION: T2alpha and Her-2/neu genes play a pivotal role in the tumor biology, CAP response, and survival of advanced thymic neoplasia patients.

Adolescent↗
PubMed2004

Contributions of bone maturation measurements to the differential diagnosis of neonatal transient hypothyroidism versus dyshormonogenetic congenital hypothyroidism.

AIM: To a) evaluate the contribution of bone maturation in the diagnosis of neonatal transient hypothyroidism versus dyshormonogenetic congenital hypothyroidism in full-term newborns, and b) use bone maturation to test the hypothesis that neonatal transient hypothyroidism is perinatal in onset. MATERIALS AND METHODS: The study included 20 patients with dyshormonogenetic and 43 with transient hypothyroidism. Thyroid function and measurements of the distal femoral epiphysis area, obtained at the time of first confirmatory diagnosis, were compared between the two groups. The epiphysis area in two control groups with normal thyroid function was also measured and compared with that in patients with transient hypothyroidism, at age 1-3 d (control A), or at the age when normal thyroid function was confirmed (control B). RESULTS: Mean epiphysis area was 0.04 cm2 in patients with dyshormonogenetic versus 0.22 cm2 in patients with transient hypothyroidism (p < 0.0001). An area <0.05 cm2 was limited to patients with dyshormonogenetic hypothyroidism. Conversely, a normal area (>0.2 cm2) was only observed in patients with transient hypothyroidism. Mean epiphysis areas in control A (0.20 cm2) and in patients with transient hypothyroidism were similar (p = 0.37), consistent with perinatal onset of transient hypothyroidism. Mean epiphysis area in control B (0.31 cm2) was significantly greater than in patients with transient hypothyroidism (p < 0.01). CONCLUSIONS: A short duration of hypothyroidism can significantly delay bone maturation. Examination of bone maturation at initial confirmatory evaluation yields important information pertaining to congenital hypothyroidism, not only to predict intellectual development, but also to evaluate the risk of dyshormonogenetic hypothyroidism.

Bone Development↗
PubMed2001

Sonographic features of xanthogranulomatous pyelonephritis.

PURPOSE: The purpose of this study was to describe the various sonographic features of xanthogranulomatous pyelonephritis (XGP). METHODS: We retrospectively reviewed the CT, sonographic, and medical records of patients diagnosed with XGP from January 1981 to December 1998. Twenty-seven patients for whom XGP was histopathologically confirmed were included in the study. There were 12 men and 15 women, with an age range of 21-86 years (mean, 57 years). All patients had undergone sonography of the kidneys. The renal size, shape, and outline were recorded. The presence of perinephric fluid accumulation, of obstructive uropathy, or of internal echoes in the dilated collecting system and the echotexture of the renal parenchyma were documented. RESULTS: We categorized the XGP into 4 groups on the basis of the sonographic features: (1) diffuse hydronephrotic, 12 patients (44%); (2) diffuse parenchymal, 9 patients (33%); (3) diffuse contracted, 4 patients (15%); and (4) segmental or focal, 2 patients (7%). A localized perinephric fluid collection was present in 4 patients (15%). The preoperative sonographic diagnoses were pyonephrosis (n = 14, 52%), renal pelvic tumor with possible associated infection (n = 5, 19%), renal parenchymal mass (n = 2, 7%), hydronephrosis (n = 2, 7%), and chronic pyelonephritis with renal atrophy (n = 4, 15%). XGP was considered a possible diagnosis in only 11 patients (41%). CONCLUSIONS: XGP has no specific sonographic features but is suggested by parenchymal thinning and hydronephrosis, sonographic signs of chronic obstructive uropathy caused by stones; echoes in the dilated collecting system; and a perinephric fluid collection. CT, needle biopsy, or both are recommended to further evaluate and confirm sonographically suspected XGP.

Adult↗
PubMed2001

Sonography of acute right side colonic diverticulitis.

BACKGROUND: To describe the prevalence and sonographic findings and ultrasound diagnostic accuracy of the right side colonic diverticulitis in patients having right lower abdominal pain with indeterminate nature. METHODS: A total of 934 patients with acute right lower abdominal pain of clinically indeterminate nature were referred for ultrasound examination (US). US studies were performed with 3.5 to 7.0 (or occasionally 10) MHz transducers using graded compression method. Twenty-three patients were finally diagnosed to have an uncomplicated acute diverticulitis of the right colon. The gray-scale sonographic images were reviewed. A retrospective study was undertaken to evaluate diagnostic contribution of US. RESULTS: The prevalence of acute right side colonic diverticulitis was 2.5% in patients with clinically indeterminate acute right lower abdominal pain. Locations of the inflamed diverticula include cecum in 6 patients, proximal ascending colon in 15 patients, and distal ascending colon in only 2 patients. Sonography detected 21 inflamed diverticula with 1 false positive and 2 false negative results. The most typical sonographic feature of an inflamed diverticulum of right side colon was a rounded or oval-shaped hypoechoic or nearly anechoic structure (52%) protruding out from the segmentally thickened colonic wall. Some of them might contain strong echoes representing gas or feces (43%), or stone in the lumen (5%). Regional pericolic or peridiverticular fat thickening was noted in 57% of patients, and segmental colon wall thickening in 38%. US examination yielded a sensitivity of 91.3%, a specificity of 99.8%, an overall accuracy of 99.5%, a positive predictive value of 95.5%, and a negative predictive value of 99.7%. A positive sonogram made the likelihood of acute right side diverticulitis 456.5 times greater compared with the pretest clinical impression. US differentiated acute right side colonic diverticulitis from acute appendicitis with a 100% accuracy. CONCLUSIONS: Ultrasound can be extremely useful in diagnosing acute right side colonic diverticulitis. Careful ultrasound evaluation of the right colon and the cecum may facilitate a correct diagnosis and help differentiate from acute appendicitis, and steer the surgeon to a more effective management.

Acute Disease↗
PubMed2001

Stepwise logistic regression analysis of tumor contour features for breast ultrasound diagnosis.

To assist the ultrasound (US) differential diagnosis of solid breast tumors by using stepwise logistic regression (SLR) analysis of tumor contour features, we retrospectively reviewed 111 medical records of digitized US images of breast pathologies. They were pathologically proved benign breast tumors from 40 patients (i.e., 40 fibroadenomas) and malignant breast tumors from 71 patients (i.e., 71 infiltrative ductal carcinomas). Radiologists, before analysis by the computer-aided diagnosis (CAD) system, segmented the tumors manually. The contour features were calculated by measuring the radial length of tumor boundaries. The features selection process was accomplished using a stepwise analysis procedure. Then, an SLR model with contour features was used to classify tumors as benign or malignant. In this experiment, cases were sampled with "leave-one-out" test methods to evaluate the SLR performance using a receiver operating characteristic (ROC) curve. The accuracy of our SLR model with contour features for classifying malignancies was 91.0% (101 of 111 tumors), the sensitivity was 97.2% (69 of 71), the specificity was 80.0% (32 of 40), the positive predictive value was 89.6% (69 of 77), and the negative predictive value was 94.1% (32 of 34). The CAD system using SLR can differentiate solid breast nodules with relatively high accuracy and its high negative predictive value could potentially help inexperienced operators to avoid misdiagnoses. Because the SLR model is trainable, it could be optimized if a larger set of tumor images were supplied.

Adolescent↗
PubMed2001

Sonographic features of breast abscesses with emphasis on "hypoechoic rim" sign.

BACKGROUND: There are only limited reports on the ultrasound (US) features of breast abscess. The purpose of this paper is to review the US features of breast abscess with emphasis on "hypoechoic rim" sign which is more commonly seen in chronic abscess. METHODS: In a period of 10 years, 20,998 patients were referred for breast US examinations. Medical records identified 204 patients in whom breast abscess was diagnosed. All patients were examined using high-resolution real-time US scanners. The initial ultrasound reports and hard copy images were all carefully reviewed. The grading of the echogenicity of the abscess was classified from grade 0 to grade 5. The contours of the lesions were described as smooth, macrolobulated, microlobulated, irregular, zigzag, spiculate or indistinct. The wall thickness was measured to document the presence of "hypoechoic rim" which denoted a wall thickness greater than 2 mm. The associated findings and other acoustic phenomena related to the lesion were recorded. RESULTS: One hundred and thirty-six patients (136/204) having specific aspiration and/or biopsy/histopathological results were included in the study. All of the 136 patients showed abnormal US findings (100%). Most lesions showed grade 1 or grade 2 echogenicity (117, 86%). The contour of the abscess was usually smooth (42, 31%), macrolobulated (42, 31%), or irregular (22, 16%). A hypoechoic rim was noticed in 18 lesions (13%). Focal skin thickening was chiefly noticed in 91% of superficial abscesses (39/43) and 17% of intramammary abscesses (14/84). Diffuse skin thickening was exclusively evident in the breasts coexisting with mastitis. Hypoechoic interstitial streaks were not a common finding (7%), occurring in acute abscesses. The other findings included surrounding hypoechoic amorphous tissue (26%), posterior wall enhancement (71%), distal enhancement (60%) and lateral shadows (57%). CONCLUSIONS: US plays an important role in confirmation of the clinical diagnosis of breast abscess and aids significantly in the management of inflammatory breast diseases. Presence of the hypoechoic rim surrounding a fluid space or a central area of low-level echoes (i.e., grade 1 to grade 3) is indicative of a chronic abscess.

Abscess↗
PubMed2001

Automatic bone age estimation based on carpal-bone image--a preliminary report.

BACKGROUND: Bone age (BA) estimation is one of the important applications of hand radiography in the area of pediatrics, especially for the diagnosis of endocrinological problems and growth disorders. BA estimation (BAE) is tedious, time-consuming and highly dependent upon the expert experience. Nowadays, most BAE standards are based on American standards, but there is no BAE standard for Taiwanese people. We attempt to construct a computerized BAE system to automate BAE and in the long run to build a BAE standard for Taiwanese. METHODS: Our BAE system is based on the carpal bone information. We propose a new 2-stage edge detection method for carpal bone feature extraction and a new method for locating the carpal bone region of interest. RESULTS: After the image is manually equalized, our BAE system can estimate the bone age automatically. The extracted carpal bone features were applied to three classifiers for age estimation: the weighted minimum distance, Bayes, and neural network classifiers. The Bayes and neural network classifiers had better results. In the 0.5-year tolerance case, they both had over 90% correct rate for both male and female training data. In the 1-year tolerance case, they could classify correctly for the male and female testing data. CONCLUSIONS: A computerized BAE system has been developed and some experiments have been conducted. It is found that the classifying results for 0.5-year tolerance are good and satisfactory.

Age Determination by Skeleton↗
PubMed2000

Hereditary haemorrhagic telangiectasia: hepatic lesions demonstrated with colour Doppler and power Doppler sonography.

Visceral vascular abnormalities in patients with hereditary haemorrhagic teleangiectasia (HHT) include teleangiectasis, arteriovenous fistula (AVF), and aneurysms. Sonographic findings and colour Doppler ultrasound (CDU) features of HHT in the liver have been described in a few reports. Presented here is the CDU finding of liver with HHT involvement in two patients, aged 52 and 29 years, respectively. Power Doppler sonography was also performed in the first patient in whom both CDU and power Doppler sonography could demonstrate the abnormal vascular channels in the liver. In the second patient, aneurysms in the left hepatic lobe and of the splenic artery were noted. Angiography was performed in both patients and confirmed the abnormal vascular lesions demonstrated by CDU and/or power Doppler sonographic findings.

Adult↗
PubMed2000

Texture analysis of breast tumors on sonograms.

We performed a feasibility study to determine if the texture features extracted from sonograms can be used to predict malignant or benign breast pathology by the proposed artificial neural network and to compare the diagnostic results with the radiologists' results. A total of 1,020 images (4 different rectangular regions from the 2 orthogonal imaging planes of each tumor) from 255 patients were used as samples. When a sonogram was performed, 1 physician identified the region of interest in the sonogram; then, a neural network model, using 24 autocorrelation texture features, classified the tumor as benign or malignant. Three radiologists who were unfamiliar with the samples also classified these images. The receiver operating characteristic (ROC) area index for the proposed neural network system is 0.9840 +/- 0.0072. The neural network identified 35 of 36 malignancies and 211 of 219 benign tumors using all 4 regions of interest. The radiologists, on average, identified 19 of 36 malignancies, with 12 tumors called indeterminate and 4 tumors called benign. We conclude that benign and malignant breast tumors can be distinguished using interpixel correlation in digital ultrasonic images.

Adolescent↗
PubMed2000

Mycotic aneurysm of the abdominal aorta in a patient undergoing hemodialysis: an unusual complication of Staphylococcus aureus bacteremia.

When Staphylococcus aureus is repeatedly positive in blood cultures even under effective antibiotics therapy (vancomycin, teicoplanin, or rifampin), computed tomography scan and sonography should be performed early to exclude mycotic aneurysm of the deeply seated arteries, especially in patients with abdominal aortic calcification. Before 1990, the most common causative organism of suprarenal aortic mycotic aneurysm was Salmonella; since 1990, it has been gram-positive cocci (i.e., Streptococcus and Staphylococcus) rather than gram-negative bacilli (i.e., Salmonella), possibly because of the more invasive procedures performed in clinical settings, but this hypothesis needs further investigation.

Aged↗
PubMed2000

Klebsiella pneumoniae renal abscess.

BACKGROUND: The clinical characteristics of renal abscess caused by Klebsiella pneumoniae have not been previously reported in case-series studies. The purpose of this study is to demonstrate the clinical characteristics of K pneumoniae renal abscess for early diagnosis and to identify the clinical risk factors associating with poor prognosis. METHODS: We retrospectively reviewed the medical records of 24 patients with K pneumoniae renal abscess, from April, 1982 through February, 1998. The clinical presentations, including the demographic characteristics, predisposing disorders, initial signs and symptoms, laboratory test results, diagnostic radiology studies, therapeutic modalities and risk factors associated with mortality were studied. RESULTS: The mean age was 58.7 years and the male to female ratio was 10:14. The most common predisposing factors were diabetes mellitus (58%), urolithiasis (25%) and immunosuppression (17%). Fever, chills and flank pain were the most common symptoms and signs, whereas pyuria, elevation of leukocyte count, glucose, blood urea nitrogen and creatinine were the common laboratory features. The distinct complications of K pneumoniae renal abscess were bacteremia in 13 (54%), emphysematous pyelonephritis in five (21%), and metastatic septic infection in three (12.5%). The cure rate was 52% (11/21) in patients treated with a combination of antibiotics and percutaneous drainage; however, six (35%) patients who survived required another surgical procedure for complete recovery. The overall mortality rate was 25%. The clinical factors of elderly age (>65 years) at presentation, lethargy, elevation of serum blood urea nitrogen and pulmonary complications were associated with poor prognoses. CONCLUSIONS: Focusing on the early diagnosis of K pneumoniae renal abscess and recognition of the prognostic factors for a poor prognosis, we highlight the specific clinical characteristics that include elderly age, lethargy, impairment of renal function, metastatic septic lesions and pulmonary complications. All patients with K pneumoniae renal abscesses should receive empiric antibiotics and percutaneous drainage or aspiration, and surgical intervention as necessary for patients with intractable disease.

Abscess↗
PubMed1999

Echo-enhancing sonography of a large-vessel hemangioma of the neck.

Because of the slow flow in the venous spaces of large-vessel hemangiomas, demonstration of color flow signals with conventional color Doppler or power Doppler sonography may be difficult. We report the case of a 22-year-old female patient with a soft tissue tumor containing multiple fluid-filled spaces in the right supraclavicular region. Gray-scale, color, and power Doppler sonography could not differentiate between cystic lymphangioma and large-vessel hemangioma. The intravenous echo-enhancing contrast agent Levovist was administered, and a significant echo-enhancing effect on color and power Doppler imaging was demonstrated in the fluid-filled spaces and lasted for about 3 minutes. Histopathologic study of the excised tumor confirmed the sonographic diagnosis of hemangioma. Levovist appears useful in depicting slow flow in a large-vessel hemangioma.

Adult↗
PubMed1999

Congenital hypothyroidism with multiple ovarian cysts.

UNLABELLED: A case of ectopic thyroid with congenital hypothyroidism presenting with bilateral multicystic ovaries without marked precocious puberty is reported. The cystic ovaries disappeared dramatically after thyroid hormone therapy. CONCLUSION: When ovarian cysts are found in prepubescent females, the possibility of associated hypothyroidism should be considered.

Age Determination by Skeleton↗
PubMed1999

Evaluation of ocular arterial changes in glaucoma with color Doppler ultrasonography.

The purpose of this study was to evaluate hemodynamic changes of the retrobulbar vasculature caused by different intraocular pressures with color Doppler ultrasonography. Fifty normal eyes in 25 patients, 13 patients with normal tension glaucoma, and 19 patients with acute glaucoma and increased intraocular pressure (greater than 30 mm Hg) were enrolled in this study. In 15 of 19 patients with acute glaucoma patients, follow-up color Doppler ultrasonography was also undertaken after laser peripheral iridectomy when the intraocular pressure had returned to normal. The peak systolic velocity, end diastolic velocity, resistive index, time average maximum velocity, and pulsatility index were compared in different vessels, including the central retinal artery, lateral posterior ciliary artery, medial posterior ciliary artery, and ophthalmic artery in each orbit. The peak systolic velocity, end diastolic velocity, and time average maximum velocity of the central retinal artery were significantly lower (P<0.01) in acute glaucoma patients than in the control group. The resistive index and pulsatility index of the central retinal artery were significantly higher (P<0.01) in acute glaucoma patients than in the control group. The end diastolic velocity of the lateral and medial posterior ciliary arteries was significantly lower in patients with acute glaucoma than in the control group, and the resistive index and pulsatility index of both of these arteries were significantly higher (P<0.001) in patients with acute glaucoma than in the control group. However, no statistical significantly differences were found in the peak systolic velocity or time average maximum velocity in either of the posterior ciliary arteries; similarly, no statistically significant differences were noted in any of the parameters in the ophthalmic artery between the control group and the group with acute glaucoma. The pulsatility index of the central retinal artery and of the lateral and medial posterior ciliary arteries was significantly lower (P<0.01) in acute glaucoma patients after laser therapy than in acute glaucoma patients before laser therapy. The resistive index of both posterior ciliary arteries was also significantly lower (P<0.004) in acute glaucoma patients after laser therapy than before laser therapy. All parameters for all vessels examined among the normal subjects, the patients with normal tension glaucoma, and the patients with acute glaucoma after laser therapy when the intraocular pressure had returned to normal showed no statistically significant differences. Color Doppler ultrasonography is a good modality for both imaging and studying the hemodynamics of the perioptic nerve vessels.

Aged↗
PubMed1999

Alternative and effective treatment of shoulder ganglion cyst: ultrasonographically guided aspiration.

The therapeutic effect of ultrasonographically guided aspiration of a ganglion cyst of the shoulder is evaluated. Fifteen patients (nine male, six female) with chronic shoulder pain were enrolled in this study. Each patient was referred to rule out rotator cuff lesion. The ultrasonographic examination showed an anechoic cystic lesion in the shoulder region in every patient and abnormality of the rotator cuff in only four patients. Under ultrasonographic guidance, an 18 gauge needle was inserted into the cyst to aspirate the fluid. Initial sonographic imaging showed the cyst, which appeared as a localized fluid accumulation and was located between the deltoid muscle and the subscapularis tendon in seven patients, between the deltoid muscle and the biceps tendon in one patient, below the coracoacromial ligament in five patients, and over suprascapular notch area in one patient. The ganglion cysts ranged in size from 3.5 to 30 mm. The amount of aspirated fluid in each cyst varied from 0.4 to 12 ml (mean, 2.6 ml +/- 3.1) with a clear or light yellowish color and a jelly-like appearance. No major complications occurred during or after this procedure. The symptom (pain) was improved after sonographically guided aspiration in each patient. Follow-up study showed complete relief of pain in four patients, marked improvement in nine patients, and mild improvement but still persistent shoulder pain in two patients. Duration of follow-up study ranged from 2 to 24 months (mean, 6.4 months +/- 6.9). The success rate for sonographically guided aspiration was 86% on the basis of marked symptom improvement or relief. Ultrasonographically guided aspiration of shoulder ganglion cysts is an effective procedure in the management of shoulder pain caused by ganglion cysts.

Adult↗
PubMed1998

Ultrasound-guided interventional procedures in splenic abscesses.

The results of ultrasound (US)-guided interventional procedures over a period of 12 years in 21 consecutive patients with splenic abscess were reviewed. The interventional procedures were done with 21- or 18-gauge needles for aspiration of relatively small abscesses (< 3.5 cm) in eight patients and with an 8.3-9.0 French pigtail catheter for continuous drainage in 13 patients with larger abscesses (> or = 3.5 cm). In some patients, multiple abscesses were treated separately according to their various sizes. More than one catheterization were done in three patients because of detached catheter or recurrent abscesses. The interventional procedures were followed by at least eight weeks of appropriate antibiotic therapy. Only one patient had the complication of minimal subcapsular hematoma which needed no further treatment. All the patients had uneventful clinical courses. US-guided interventional procedure proved to be a treatment-of-choice for splenic abscess, and may avoid splenectomy by conserving the spleen.

Abscess↗