San-Kan Lee - Academia.edu (original) (raw)

Papers by San-Kan Lee

Research paper thumbnail of Multiple Intracranial Germ Cell Tumors

中華放射線醫學雜誌, Dec 1, 1992

We report two unusual patterns of intracranial germ cell tumors consisting of 2 different types o... more We report two unusual patterns of intracranial germ cell tumors consisting of 2 different types of tumor cells in each case. One patient had multiple tumors in suprasellar cistern, cerebral hemisphere, and pineal region, where radiation therapy led to a good response. Tumor recurred 1 year later, and this was proved to be germinoma mixed with immature teratoma. Another patient had pineal region germinoma. This tumor disappeared for 8 years after radiotherapy. The tumors that recurred 8 years later in the pineal region and suprasellar cistern, also were suppressed by radiation; however, during radiotherapy, two rapidly growing tumor masses were found in both frontal lobes, and pathology proved them to be yolk sac tumor. Germ cell tumor therefore may has mixed cell type, and only germinoma has good response to radiotherapy whereas the nongerminomatous tumors have poor prognosis.

Research paper thumbnail of Perforation of Ileum by Fish Bone-A Case Report

中華放射線醫學雜誌, Dec 1, 1990

A case of mesentric granuloma with surrounding focal abscess formation caused by fish bone perfor... more A case of mesentric granuloma with surrounding focal abscess formation caused by fish bone perforation of the terminal ileum is presented. Although the variable clinical manifestations and non-specific radiographic pictures impede a preoperatuve diqgnosis, the possibility of gut perforation caused by foreign body should be considered when a vulnerable site is involved and clinical hostory indicated

Research paper thumbnail of MRI of concurrent spinal meningioma, ependymoma, and syringomyelia

Research paper thumbnail of Post-traumatic Avascular Necrosis: Application of the Hawkins Sign in the Talus and the Femoral Head

中華放射線醫學雜誌, Dec 1, 1999

The Hawkins sign was thought to be useful as an early negative predictor of avascular necrosis (A... more The Hawkins sign was thought to be useful as an early negative predictor of avascular necrosis (AVN) following a fracture through the talar neck. It had not, however, been applied to fractures through the femoral neck. We evaluated the applicability of the Hawkins sign for fractures through the femoral neck, and compared with those through the talus. Radiographs of 10 ankles with fracture of the talus and 12 hips with fracture of the femoral neck in our hospital were reviewed retrospectively. In 6 of the ankles, the Hawkins sign was positive without evidence of AVN on serial follow-up radiographs. The rest of the ankles in which the Hawkins sign was absent eventually developed AVN. In contrast, none of the hips showed a positive Hawkins sign, but AVN was noted in only 2 cases. We concluded that the Hawkins sign is useful for prediction of the blood-supply status of the talar body, but not for the femoral head. The cause of this discrepancy between the talus and the femur is unknown. Different areas of weight-bearing may be a possible factor. A further study with a large number of cases and with long-term longitudinal radiographic follow-up is necessary.

Research paper thumbnail of The Differential Diagnosis of Ascites: CT Evaluation

Journal of Medical Sciences, Aug 1, 1990

Five indices were used as rules of thumb to review abdominal computed tomograms (CT) of consecuti... more Five indices were used as rules of thumb to review abdominal computed tomograms (CT) of consecutive 30 ascitic patients in an attempt to differentiate benign from malignant ascites. These included: (1) distribution of ascites; (2) bowel-mesentery pattern (3) intact intra-/extraperitoneal interface; (4) associated hepatic or non-hepatic metastases; and (5) retro-peritoneal lymphadenopathy. Among these indices, the direct identification of abdominal mass or lymphadenopathy had highest accuracy (1 00%) in predicting malignant ascites. Obliteration of intra-/extraperitoneal interface and matted bowel-mesentery pattern reflected high possibility of malignancy (sensitivity 60%, 56.25%, respectively, specificity 80%, 71.42%, repectively), and the inflammatory process, was the next probability. The distribution of fluid in cases with large or small amount of ascites was not very helpful in differential diagnosis (sensitivity 31.25, specificity 78.50%). The most frequent sites of fluid accumulation in our cases were perihepatic and right paracolic gutter in contrast to the least site in the lesser sac. A full knowledge of these indices might further aid in differentiation of the nature of the ascites.

Research paper thumbnail of The Application of Three-Dimensional Computed Tomography in Skeletal Trauma: A Preliminary Report

中華放射線醫學雜誌, Dec 1, 1993

Most bony fractures can be identified with plain radiography, tomography or conventional computed... more Most bony fractures can be identified with plain radiography, tomography or conventional computed tomography (CCT). Bony fractures in areas with complex anatomy, however, are hard to be visualized. Thus preoperative planning is often difficult. With application of three-dimensional computed tomography (3-DCT), the bony lesions in 15 patients including 13 traumatic bony fractures, I vertebral metastasis with pathological fracture, and 1 traumatic temporomandibular joint (TMJ) dislocation could be clearly identified. However, bony fractures in the central portion of the craniofacial bones and traumatic TMJ dislocation were missed. In addition, thin or small bones and deep bone pits can produce pseudoforamina or pseudofractures on 3-DCT. We concluded that 3-DCT can be a good imaging modality, in conjunction with CCT, in the evaluation of bony fractures, especially in the areas with complex anatomy, i.e. facial bones, spine, shoulders and pelvis, etc.

Research paper thumbnail of Cerebral Venous Angiomas

中華放射線醫學雜誌, Dec 1, 1990

Cerebral venous angioma as a rare vascular malformation has been found only 212 cases over the pa... more Cerebral venous angioma as a rare vascular malformation has been found only 212 cases over the past 30 years. We recently obeserved 16 patients with 19 cerebral venous angiomas. The majority of them were documented with angiogaphically characteristic findings of ”caput Medusae” in the venous phase except one case because of previous venous thrombosis. In our study, infratentorial venous angiomas were more common than supratentorial ones, which is different most previous Western reports. In addition, patients were predominantly female.

Research paper thumbnail of Duodenal Rupture Due to Blunt Abdominal Trauma: Evaluation with Plain Film and Computed Tomography

中華放射線醫學雜誌, Mar 1, 1991

We studied retrospectively 14 patients with surgically proved duodenal rupture due to blunt abdom... more We studied retrospectively 14 patients with surgically proved duodenal rupture due to blunt abdominal trauma. Among them, plain abdominal films were taken in all cases, abdominal computed tomography (CT) in 10 cases and upper GI series in 4 cases. Plain abdominal films revealed retroperitoneal emphysema outlining the right kidney in 4 cases and along the right psoas muscle in 1 case. Other non-specific findings suggestive of duodenal rupture were demostrated in 79% of the patients. These included obliteration of right psoas muscle margin (9 cases), right renal outline (7 cases) or scoliosis of lumbar spine (7 cases). Using CT, 8 cases (80%) could clearly demostrate fluid collection at right anterior pararenal space and among them, 6 cases (60%) showed gaseous collection at the right anterior pararenal or/and perirenal space and one case showed gaseous collection along right psoas margin. Three out of 4cases of upper GI series could demostrate extravasation of contrast agent through the perforated duodenum. CT scanning was more sensitive in detecting retroperitoneal gas and fluid extravasated from perforated duodenum which were often being missed or misinterpreted as superimposed fecal gaseous materials on their plain films.

Research paper thumbnail of Peer reviewing of screening mammography in Taiwan: its reliability and the improvement

PubMed, 2013

Background: Early detection with screening mammography can potentially reduce breast cancer morta... more Background: Early detection with screening mammography can potentially reduce breast cancer mortality rates. To achieve an efficient screening, a peer review system provides a compensatory double-check reviewing, will hopefully to prevent the omission of detectable lesions and reduce unnecessary recall. Methods: In 2009, 4643 initial mammographic screenings reported by 74 screening radiologists had negative results with a recall rate of less than 5%. In the same year, 2538 initial positives screened by 18 screening radiologists had a recall rate higher than 15%. Those 7181 randomized screenings were evenly distributed for reassessment by 39 reviewing radiologists. The disagreement of assessments between the reviewers and screening radiologists was recorded. The differential rate was defined as the number of the disagreements divided by the number of audited films reviewed by a screening radiologist. The equality of the differential rates for each screening radiologists with negative and positive assessments was compared by a Chi-square test. The performance of the 39 auditors was measured by the Kendall's tau statistic. P values less than 0.05 were considered statistically significant. Results: The mean differential rate for screening radiologists of negative assessments was 6.7% (P = 0.588), while 35.0% for positive assessments were significant (P < 0.001). The result indicated that most of the initial negative assessments reported by the screening radiologists were generally accepted by the reviewers but not the positive assessments. With respect to the 39 reviewers, there was no significant evidence for the association of the difference rates between negative and positive assessments. Nine reviewers were found to have their differential rate for negative and positive assessments larger than the average of the population. Eleven reviewers were found to have their differential rates smaller than the average for both. Thirteen reviewers had their differential rates smaller than the average for negative assessments but larger than the average for positive assessments. The opposite condition was found for six reviewers. The Kendall's tau statistic was 0.038 (P = 0.735). Conclusions: Reviewers usually agreed with the opinion of the initial screening doctors who reported negative findings. Therefore, a 5% recall rate as the lower range of reviewing negatives may be still too high. The recall rate of more than 15% was significantly related to improper interpretation, especially when the differential rate is 25% or higher, a warning to the underperforming screening radiologist is recommended. An ideal reviewer should interpret films independently. Reviewers with tendencies to be followers or contrarians should not be enrolled in the reviewing system.

Research paper thumbnail of Clinical Evaluation of Gallbladder Diseases by Endoscopic Ultrasonography

中華民國消化系醫學會雜誌, Dec 1, 1986

Endoscopic ultrasonography enabled insertion directly into the esophagus, stomach or duodenum for... more Endoscopic ultrasonography enabled insertion directly into the esophagus, stomach or duodenum for observation of the target organ and was useful in collecting information on gallbladder status prior to operation. One hundred and thirty-eight cases were studied by endoscopic ultrasonography from January 1985 to July 1986. The percentage of true positive findings for gallstones, gallbladder polyps, gallbladder cancer, cholecystitis and normal gallbladder by endoscopic ultrasonography were 96.6%(28/29 cases), 95.5%(21/22), 50%(2/4), 93.8%(15/16) and 100%(67/67), respectively. These results were slightly superior to those achieved by conventional ultrasonography study. In order to obtain detailed images of endoscopic ultrasonography in gallbladder diseases, position change with dislodgement of probes is sometimes needed.

Research paper thumbnail of Percutaneous CT-guided Custom-designed One-step Abscess Drainage in Critically-ill Patients

中華放射線醫學雜誌, Feb 1, 1998

To design an instrument for one- step percutaneous abscess drainage (PAD) to shorten the duration... more To design an instrument for one- step percutaneous abscess drainage (PAD) to shorten the duration of computed tomography (CT)-guided procedure for patients in critical condition. A custom-designed one-step instrument was designed as a combination of a percutaneous nephrostomy pigtail catheter and a puncture needle. In twenty-two critically-ill patients, 22 CT-guided drainage procedures were performed in 19 cases with intraabdominal, retroperitoneal, or pelvic abscesses. Drainage procedures were cancelled in two cases as a result of preoperation CT study. One case failed due to a complicated iatrogenic pneumothorax. The custom- designed drainage combinations facilitated the abscess drainage procedures in critically-ill patients. The average duration for one drainage procedure had been shortened to less than 25 minutes with special care taken for the techniques needed to locate the position and direction of drainage catheter. The overall success and complication rates were 95% and 10%, respectively. Percutaneous CT-guided one-step drainage may provide a more efficient and safer method than sonography-or fluoroscopy-guided procedures in treating critically-ill patients with abscess formations. Custom- designed one-step drainage instrument fulfills both clinical and economic requirements, as compared with the commercial one- stick design.

Research paper thumbnail of Hepatocellular Carcinoma Treated with Percutaneous Radiofrequency Ablation: Evaluated with Sequential Biphasic Helical CT

Research paper thumbnail of Differential Diagnosis of Invasive Thymoma and Thymic Carcinoma by CT Findings

中華放射線醫學雜誌, Oct 1, 1999

The clinical behavior and prognosis of invasive thymoma and thymic carcinoma are different, and c... more The clinical behavior and prognosis of invasive thymoma and thymic carcinoma are different, and computed tomography is the most widely applied and advanced imaging modality for diagnosis of these diseases. It is important to evaluate the usefulness of CT characteristics in their differentiation. Retrospectively, we evaluated the CT findings of invasive thymoma and thymic carcinoma to determine the differential points between them. Seventeen patients with invasive thynioma and 25 patients with thynfic carcinoma, that were confirmed by surgical resection or by fine needle biopsy, were included in this study. All tumors were located in the anterior mediastinal prevascular space. Special attention was given to the following CT findings: homogeneity, attenuation, invasion of adjacent cardiovascular structure, mediastinal lymph nodes, pleural implants, extrathymic metastases, and calcification. Univariate and multivariate analyses were performed with Fisher's exact test and binary logistic regression. Invasion of adjacent cardiovascular structure was seen in three patients (17%) with invasive thymoma, and 20 patients (80%) with thymic carcinoma. Significant mediastinal lymphadenopathy was seen in two patients (12%) with invasive thymoma, and nine patients (36%) with thymic carcinoma. Pleural implants were observed in eight patients (47%) with invasive thymoma, and 12 patients (48%) with thymic carcinoma. Metastases to the lung, adrenal gland, liver, bone, spleen, or retroperitoneal lymph nodes were observed in 12 patients (48%) with thymic carcinoma, but were absent from patients with invasive thymoma. According to Fisher's exact test, there are four significant signs by CT findings associated with differentiation between thymic carcinoma and invasive thymonia: (1) inhomogeneous mass content, (2) infiltration of adjacent pericardium, (3) encasement of great vessels, and (4) extrathymic metastases. Binary logistic regression analysis shows that thymic carcinoma is more likely rather than invasive thymoma with the presence of infiltration of adjacent pericardiumn and encasement of great vessels. Infiltration of adjacent pericardium is more predominant in predicting thymic carcinoma than is encasement of great vessels. If a tumor can be attributed to thymic origin by fine needle cytological study or by biochemical stain, then thymic carcinoma would be more likely with the presence of infiltration of adjacent pericardium and encasement of great vessels on CT scan.

Research paper thumbnail of An Economical, Personal Computer–based Picture Archiving and Communication System

Radiographics, Mar 1, 1999

Research paper thumbnail of Spontaneous Retroperitoneal Hemorrhage from Kidney Causes

European Urology, 1988

Spontaneous retroperitoneal hemorrhage is an uncommon entity and even rarer when the underlying c... more Spontaneous retroperitoneal hemorrhage is an uncommon entity and even rarer when the underlying cause is from the kidney. Renal tumors comprise the majority of atraumatic kidney rupture. Renal cell carcinoma and angiomyolipoma are the most common diseases in this group. Oral anticoagulant therapy and hemodialysis could be responsible for a few cases. In 3 reported cases no pathological explanation could be found. With the help of modern facilities, diagnosis can be made preoperatively and conservative surgery is indicated in these patients. However, nephrectomy is the treatment of choice for patients presenting with shock as the initial symptom or solid renal mass with perirenal hematoma.

Research paper thumbnail of Lipomatosis of Kidney Mimicking Hydronephrosis or Urothelial Carcinoma of Renal Pelvis on Sonography

Ultrasound in Medicine and Biology, 2017

Research paper thumbnail of Congenital Coronary Artery Fistula-Case Report and Review of Literatures

中華放射線醫學雜誌, Sep 1, 1992

A 19-year-old woman was diagnosed to have a coronary artery fistula communicating with right vent... more A 19-year-old woman was diagnosed to have a coronary artery fistula communicating with right ventricle was made by noninvasive technique using MRI, which provided high-quality images of the course of the dilated coronary artery and its termination in the right ventricle. The advantage of this noninvasive multiplanar imaging technique for visulization of coronary artery fistula and dilated coronary arteries are described.

Research paper thumbnail of Ultrasound and CT Findings of Hepatic Amebic Abscess

中華放射線醫學雜誌, Jun 1, 1996

A series of 35 patients who had hepatic amebic abscess was presented. Thirty-six sonograms in 27 ... more A series of 35 patients who had hepatic amebic abscess was presented. Thirty-six sonograms in 27 patients and 27 computed tomographic (CT) scans in 23 patients were reviewed. Abnormalities were detected in all cases. The imaging appearance of the lesions varied from well-defined, rounded cavities to ill-defined borders with heterogeneous content, indistinguishable from other hepatic abscesses or even neoplasms. The most common ultrasonographic finding was a well-defined homogeneous hypoechoic lesion with posterior enhancement in the peripheral portion of liver parenchyma. The most common CT finding was a well-defined cystic lesion with nodularity or mild septation of wall. No gas was present in these lesions. A peripheral hypodense rim was seen in 22%. However, no pathognomonic sign of amebic liver abscess could be found on CT.

Research paper thumbnail of Neurilemmoma of the oculomotor nerve presenting as an orbital mass: MR findings

American Journal of Neuroradiology, Sep 1, 1993

Research paper thumbnail of A Study of Percutaneous Transthoracic Needle Biopsy

中華放射線醫學雜誌, Mar 1, 1991

The clinical application of percutaneous transthoracic needle biopsy (PTNB) has been established ... more The clinical application of percutaneous transthoracic needle biopsy (PTNB) has been established recently owing to improved imaging capabilities, biopsy techniques and cytopathologic diagnosis. Several authors have demonstrated its extremely high accuracy for the diagnosis of malignancy. We reviewed 134 patients who had sufficient medical records and biopsy results from TCVGH and RMH. The sensitivity of PTNB in detecting malignant neoplasm in this study was 90% and the specificity was 97.7%. The overall accuracy was 91.8%. The site or size of the lesions did not exert any influence on the outcome of PTNB. The most common complications during the procedure was pneumothorax, which occurred in 20% of the patients, but only 7 needed further management. We conclude that PTNB is a relatively simple and safe procedure that can provide high diagnostic accuracy in patients with pulmonary, hilar or mediastinal masses.

Research paper thumbnail of Multiple Intracranial Germ Cell Tumors

中華放射線醫學雜誌, Dec 1, 1992

We report two unusual patterns of intracranial germ cell tumors consisting of 2 different types o... more We report two unusual patterns of intracranial germ cell tumors consisting of 2 different types of tumor cells in each case. One patient had multiple tumors in suprasellar cistern, cerebral hemisphere, and pineal region, where radiation therapy led to a good response. Tumor recurred 1 year later, and this was proved to be germinoma mixed with immature teratoma. Another patient had pineal region germinoma. This tumor disappeared for 8 years after radiotherapy. The tumors that recurred 8 years later in the pineal region and suprasellar cistern, also were suppressed by radiation; however, during radiotherapy, two rapidly growing tumor masses were found in both frontal lobes, and pathology proved them to be yolk sac tumor. Germ cell tumor therefore may has mixed cell type, and only germinoma has good response to radiotherapy whereas the nongerminomatous tumors have poor prognosis.

Research paper thumbnail of Perforation of Ileum by Fish Bone-A Case Report

中華放射線醫學雜誌, Dec 1, 1990

A case of mesentric granuloma with surrounding focal abscess formation caused by fish bone perfor... more A case of mesentric granuloma with surrounding focal abscess formation caused by fish bone perforation of the terminal ileum is presented. Although the variable clinical manifestations and non-specific radiographic pictures impede a preoperatuve diqgnosis, the possibility of gut perforation caused by foreign body should be considered when a vulnerable site is involved and clinical hostory indicated

Research paper thumbnail of MRI of concurrent spinal meningioma, ependymoma, and syringomyelia

Research paper thumbnail of Post-traumatic Avascular Necrosis: Application of the Hawkins Sign in the Talus and the Femoral Head

中華放射線醫學雜誌, Dec 1, 1999

The Hawkins sign was thought to be useful as an early negative predictor of avascular necrosis (A... more The Hawkins sign was thought to be useful as an early negative predictor of avascular necrosis (AVN) following a fracture through the talar neck. It had not, however, been applied to fractures through the femoral neck. We evaluated the applicability of the Hawkins sign for fractures through the femoral neck, and compared with those through the talus. Radiographs of 10 ankles with fracture of the talus and 12 hips with fracture of the femoral neck in our hospital were reviewed retrospectively. In 6 of the ankles, the Hawkins sign was positive without evidence of AVN on serial follow-up radiographs. The rest of the ankles in which the Hawkins sign was absent eventually developed AVN. In contrast, none of the hips showed a positive Hawkins sign, but AVN was noted in only 2 cases. We concluded that the Hawkins sign is useful for prediction of the blood-supply status of the talar body, but not for the femoral head. The cause of this discrepancy between the talus and the femur is unknown. Different areas of weight-bearing may be a possible factor. A further study with a large number of cases and with long-term longitudinal radiographic follow-up is necessary.

Research paper thumbnail of The Differential Diagnosis of Ascites: CT Evaluation

Journal of Medical Sciences, Aug 1, 1990

Five indices were used as rules of thumb to review abdominal computed tomograms (CT) of consecuti... more Five indices were used as rules of thumb to review abdominal computed tomograms (CT) of consecutive 30 ascitic patients in an attempt to differentiate benign from malignant ascites. These included: (1) distribution of ascites; (2) bowel-mesentery pattern (3) intact intra-/extraperitoneal interface; (4) associated hepatic or non-hepatic metastases; and (5) retro-peritoneal lymphadenopathy. Among these indices, the direct identification of abdominal mass or lymphadenopathy had highest accuracy (1 00%) in predicting malignant ascites. Obliteration of intra-/extraperitoneal interface and matted bowel-mesentery pattern reflected high possibility of malignancy (sensitivity 60%, 56.25%, respectively, specificity 80%, 71.42%, repectively), and the inflammatory process, was the next probability. The distribution of fluid in cases with large or small amount of ascites was not very helpful in differential diagnosis (sensitivity 31.25, specificity 78.50%). The most frequent sites of fluid accumulation in our cases were perihepatic and right paracolic gutter in contrast to the least site in the lesser sac. A full knowledge of these indices might further aid in differentiation of the nature of the ascites.

Research paper thumbnail of The Application of Three-Dimensional Computed Tomography in Skeletal Trauma: A Preliminary Report

中華放射線醫學雜誌, Dec 1, 1993

Most bony fractures can be identified with plain radiography, tomography or conventional computed... more Most bony fractures can be identified with plain radiography, tomography or conventional computed tomography (CCT). Bony fractures in areas with complex anatomy, however, are hard to be visualized. Thus preoperative planning is often difficult. With application of three-dimensional computed tomography (3-DCT), the bony lesions in 15 patients including 13 traumatic bony fractures, I vertebral metastasis with pathological fracture, and 1 traumatic temporomandibular joint (TMJ) dislocation could be clearly identified. However, bony fractures in the central portion of the craniofacial bones and traumatic TMJ dislocation were missed. In addition, thin or small bones and deep bone pits can produce pseudoforamina or pseudofractures on 3-DCT. We concluded that 3-DCT can be a good imaging modality, in conjunction with CCT, in the evaluation of bony fractures, especially in the areas with complex anatomy, i.e. facial bones, spine, shoulders and pelvis, etc.

Research paper thumbnail of Cerebral Venous Angiomas

中華放射線醫學雜誌, Dec 1, 1990

Cerebral venous angioma as a rare vascular malformation has been found only 212 cases over the pa... more Cerebral venous angioma as a rare vascular malformation has been found only 212 cases over the past 30 years. We recently obeserved 16 patients with 19 cerebral venous angiomas. The majority of them were documented with angiogaphically characteristic findings of ”caput Medusae” in the venous phase except one case because of previous venous thrombosis. In our study, infratentorial venous angiomas were more common than supratentorial ones, which is different most previous Western reports. In addition, patients were predominantly female.

Research paper thumbnail of Duodenal Rupture Due to Blunt Abdominal Trauma: Evaluation with Plain Film and Computed Tomography

中華放射線醫學雜誌, Mar 1, 1991

We studied retrospectively 14 patients with surgically proved duodenal rupture due to blunt abdom... more We studied retrospectively 14 patients with surgically proved duodenal rupture due to blunt abdominal trauma. Among them, plain abdominal films were taken in all cases, abdominal computed tomography (CT) in 10 cases and upper GI series in 4 cases. Plain abdominal films revealed retroperitoneal emphysema outlining the right kidney in 4 cases and along the right psoas muscle in 1 case. Other non-specific findings suggestive of duodenal rupture were demostrated in 79% of the patients. These included obliteration of right psoas muscle margin (9 cases), right renal outline (7 cases) or scoliosis of lumbar spine (7 cases). Using CT, 8 cases (80%) could clearly demostrate fluid collection at right anterior pararenal space and among them, 6 cases (60%) showed gaseous collection at the right anterior pararenal or/and perirenal space and one case showed gaseous collection along right psoas margin. Three out of 4cases of upper GI series could demostrate extravasation of contrast agent through the perforated duodenum. CT scanning was more sensitive in detecting retroperitoneal gas and fluid extravasated from perforated duodenum which were often being missed or misinterpreted as superimposed fecal gaseous materials on their plain films.

Research paper thumbnail of Peer reviewing of screening mammography in Taiwan: its reliability and the improvement

PubMed, 2013

Background: Early detection with screening mammography can potentially reduce breast cancer morta... more Background: Early detection with screening mammography can potentially reduce breast cancer mortality rates. To achieve an efficient screening, a peer review system provides a compensatory double-check reviewing, will hopefully to prevent the omission of detectable lesions and reduce unnecessary recall. Methods: In 2009, 4643 initial mammographic screenings reported by 74 screening radiologists had negative results with a recall rate of less than 5%. In the same year, 2538 initial positives screened by 18 screening radiologists had a recall rate higher than 15%. Those 7181 randomized screenings were evenly distributed for reassessment by 39 reviewing radiologists. The disagreement of assessments between the reviewers and screening radiologists was recorded. The differential rate was defined as the number of the disagreements divided by the number of audited films reviewed by a screening radiologist. The equality of the differential rates for each screening radiologists with negative and positive assessments was compared by a Chi-square test. The performance of the 39 auditors was measured by the Kendall's tau statistic. P values less than 0.05 were considered statistically significant. Results: The mean differential rate for screening radiologists of negative assessments was 6.7% (P = 0.588), while 35.0% for positive assessments were significant (P < 0.001). The result indicated that most of the initial negative assessments reported by the screening radiologists were generally accepted by the reviewers but not the positive assessments. With respect to the 39 reviewers, there was no significant evidence for the association of the difference rates between negative and positive assessments. Nine reviewers were found to have their differential rate for negative and positive assessments larger than the average of the population. Eleven reviewers were found to have their differential rates smaller than the average for both. Thirteen reviewers had their differential rates smaller than the average for negative assessments but larger than the average for positive assessments. The opposite condition was found for six reviewers. The Kendall's tau statistic was 0.038 (P = 0.735). Conclusions: Reviewers usually agreed with the opinion of the initial screening doctors who reported negative findings. Therefore, a 5% recall rate as the lower range of reviewing negatives may be still too high. The recall rate of more than 15% was significantly related to improper interpretation, especially when the differential rate is 25% or higher, a warning to the underperforming screening radiologist is recommended. An ideal reviewer should interpret films independently. Reviewers with tendencies to be followers or contrarians should not be enrolled in the reviewing system.

Research paper thumbnail of Clinical Evaluation of Gallbladder Diseases by Endoscopic Ultrasonography

中華民國消化系醫學會雜誌, Dec 1, 1986

Endoscopic ultrasonography enabled insertion directly into the esophagus, stomach or duodenum for... more Endoscopic ultrasonography enabled insertion directly into the esophagus, stomach or duodenum for observation of the target organ and was useful in collecting information on gallbladder status prior to operation. One hundred and thirty-eight cases were studied by endoscopic ultrasonography from January 1985 to July 1986. The percentage of true positive findings for gallstones, gallbladder polyps, gallbladder cancer, cholecystitis and normal gallbladder by endoscopic ultrasonography were 96.6%(28/29 cases), 95.5%(21/22), 50%(2/4), 93.8%(15/16) and 100%(67/67), respectively. These results were slightly superior to those achieved by conventional ultrasonography study. In order to obtain detailed images of endoscopic ultrasonography in gallbladder diseases, position change with dislodgement of probes is sometimes needed.

Research paper thumbnail of Percutaneous CT-guided Custom-designed One-step Abscess Drainage in Critically-ill Patients

中華放射線醫學雜誌, Feb 1, 1998

To design an instrument for one- step percutaneous abscess drainage (PAD) to shorten the duration... more To design an instrument for one- step percutaneous abscess drainage (PAD) to shorten the duration of computed tomography (CT)-guided procedure for patients in critical condition. A custom-designed one-step instrument was designed as a combination of a percutaneous nephrostomy pigtail catheter and a puncture needle. In twenty-two critically-ill patients, 22 CT-guided drainage procedures were performed in 19 cases with intraabdominal, retroperitoneal, or pelvic abscesses. Drainage procedures were cancelled in two cases as a result of preoperation CT study. One case failed due to a complicated iatrogenic pneumothorax. The custom- designed drainage combinations facilitated the abscess drainage procedures in critically-ill patients. The average duration for one drainage procedure had been shortened to less than 25 minutes with special care taken for the techniques needed to locate the position and direction of drainage catheter. The overall success and complication rates were 95% and 10%, respectively. Percutaneous CT-guided one-step drainage may provide a more efficient and safer method than sonography-or fluoroscopy-guided procedures in treating critically-ill patients with abscess formations. Custom- designed one-step drainage instrument fulfills both clinical and economic requirements, as compared with the commercial one- stick design.

Research paper thumbnail of Hepatocellular Carcinoma Treated with Percutaneous Radiofrequency Ablation: Evaluated with Sequential Biphasic Helical CT

Research paper thumbnail of Differential Diagnosis of Invasive Thymoma and Thymic Carcinoma by CT Findings

中華放射線醫學雜誌, Oct 1, 1999

The clinical behavior and prognosis of invasive thymoma and thymic carcinoma are different, and c... more The clinical behavior and prognosis of invasive thymoma and thymic carcinoma are different, and computed tomography is the most widely applied and advanced imaging modality for diagnosis of these diseases. It is important to evaluate the usefulness of CT characteristics in their differentiation. Retrospectively, we evaluated the CT findings of invasive thymoma and thymic carcinoma to determine the differential points between them. Seventeen patients with invasive thynioma and 25 patients with thynfic carcinoma, that were confirmed by surgical resection or by fine needle biopsy, were included in this study. All tumors were located in the anterior mediastinal prevascular space. Special attention was given to the following CT findings: homogeneity, attenuation, invasion of adjacent cardiovascular structure, mediastinal lymph nodes, pleural implants, extrathymic metastases, and calcification. Univariate and multivariate analyses were performed with Fisher's exact test and binary logistic regression. Invasion of adjacent cardiovascular structure was seen in three patients (17%) with invasive thymoma, and 20 patients (80%) with thymic carcinoma. Significant mediastinal lymphadenopathy was seen in two patients (12%) with invasive thymoma, and nine patients (36%) with thymic carcinoma. Pleural implants were observed in eight patients (47%) with invasive thymoma, and 12 patients (48%) with thymic carcinoma. Metastases to the lung, adrenal gland, liver, bone, spleen, or retroperitoneal lymph nodes were observed in 12 patients (48%) with thymic carcinoma, but were absent from patients with invasive thymoma. According to Fisher's exact test, there are four significant signs by CT findings associated with differentiation between thymic carcinoma and invasive thymonia: (1) inhomogeneous mass content, (2) infiltration of adjacent pericardium, (3) encasement of great vessels, and (4) extrathymic metastases. Binary logistic regression analysis shows that thymic carcinoma is more likely rather than invasive thymoma with the presence of infiltration of adjacent pericardiumn and encasement of great vessels. Infiltration of adjacent pericardium is more predominant in predicting thymic carcinoma than is encasement of great vessels. If a tumor can be attributed to thymic origin by fine needle cytological study or by biochemical stain, then thymic carcinoma would be more likely with the presence of infiltration of adjacent pericardium and encasement of great vessels on CT scan.

Research paper thumbnail of An Economical, Personal Computer–based Picture Archiving and Communication System

Radiographics, Mar 1, 1999

Research paper thumbnail of Spontaneous Retroperitoneal Hemorrhage from Kidney Causes

European Urology, 1988

Spontaneous retroperitoneal hemorrhage is an uncommon entity and even rarer when the underlying c... more Spontaneous retroperitoneal hemorrhage is an uncommon entity and even rarer when the underlying cause is from the kidney. Renal tumors comprise the majority of atraumatic kidney rupture. Renal cell carcinoma and angiomyolipoma are the most common diseases in this group. Oral anticoagulant therapy and hemodialysis could be responsible for a few cases. In 3 reported cases no pathological explanation could be found. With the help of modern facilities, diagnosis can be made preoperatively and conservative surgery is indicated in these patients. However, nephrectomy is the treatment of choice for patients presenting with shock as the initial symptom or solid renal mass with perirenal hematoma.

Research paper thumbnail of Lipomatosis of Kidney Mimicking Hydronephrosis or Urothelial Carcinoma of Renal Pelvis on Sonography

Ultrasound in Medicine and Biology, 2017

Research paper thumbnail of Congenital Coronary Artery Fistula-Case Report and Review of Literatures

中華放射線醫學雜誌, Sep 1, 1992

A 19-year-old woman was diagnosed to have a coronary artery fistula communicating with right vent... more A 19-year-old woman was diagnosed to have a coronary artery fistula communicating with right ventricle was made by noninvasive technique using MRI, which provided high-quality images of the course of the dilated coronary artery and its termination in the right ventricle. The advantage of this noninvasive multiplanar imaging technique for visulization of coronary artery fistula and dilated coronary arteries are described.

Research paper thumbnail of Ultrasound and CT Findings of Hepatic Amebic Abscess

中華放射線醫學雜誌, Jun 1, 1996

A series of 35 patients who had hepatic amebic abscess was presented. Thirty-six sonograms in 27 ... more A series of 35 patients who had hepatic amebic abscess was presented. Thirty-six sonograms in 27 patients and 27 computed tomographic (CT) scans in 23 patients were reviewed. Abnormalities were detected in all cases. The imaging appearance of the lesions varied from well-defined, rounded cavities to ill-defined borders with heterogeneous content, indistinguishable from other hepatic abscesses or even neoplasms. The most common ultrasonographic finding was a well-defined homogeneous hypoechoic lesion with posterior enhancement in the peripheral portion of liver parenchyma. The most common CT finding was a well-defined cystic lesion with nodularity or mild septation of wall. No gas was present in these lesions. A peripheral hypodense rim was seen in 22%. However, no pathognomonic sign of amebic liver abscess could be found on CT.

Research paper thumbnail of Neurilemmoma of the oculomotor nerve presenting as an orbital mass: MR findings

American Journal of Neuroradiology, Sep 1, 1993

Research paper thumbnail of A Study of Percutaneous Transthoracic Needle Biopsy

中華放射線醫學雜誌, Mar 1, 1991

The clinical application of percutaneous transthoracic needle biopsy (PTNB) has been established ... more The clinical application of percutaneous transthoracic needle biopsy (PTNB) has been established recently owing to improved imaging capabilities, biopsy techniques and cytopathologic diagnosis. Several authors have demonstrated its extremely high accuracy for the diagnosis of malignancy. We reviewed 134 patients who had sufficient medical records and biopsy results from TCVGH and RMH. The sensitivity of PTNB in detecting malignant neoplasm in this study was 90% and the specificity was 97.7%. The overall accuracy was 91.8%. The site or size of the lesions did not exert any influence on the outcome of PTNB. The most common complications during the procedure was pneumothorax, which occurred in 20% of the patients, but only 7 needed further management. We conclude that PTNB is a relatively simple and safe procedure that can provide high diagnostic accuracy in patients with pulmonary, hilar or mediastinal masses.