Biomedical subjects

T S Jaw

Publications and source records attributed to T S Jaw.

At least 19 recordsLinked to original sources

PubMed1999

MR cholangiography in the evaluation of neonatal cholestasis.

PURPOSE: To evaluate the usefulness of magnetic resonance (MR) cholangiography in excluding biliary atresia as the cause of neonatal cholestasis. MATERIALS AND METHODS: MR cholangiography was performed on 10 control and 16 jaundiced neonates and infants aged 3 days to 5 months. Diagnosis of biliary atresia (n = 6) was confirmed with surgery and liver biopsy, with or without surgical cholangiography. Diagnosis of neonatal hepatitis (n = 9) was confirmed with clinical follow-up until jaundice resolved. In one infant, paucity of intrahepatic ducts was diagnosed at liver biopsy. MR cholangiography was performed with respiratory-triggered, heavily T2-weighted turbo spin-echo and optional inversion-recovery turbo spin-echo sequences. Diagnosis of biliary atresia was based on nonvisualization of either the common bile duct or common hepatic duct. Cholescintigraphy with technetium 99m disofenin was performed in all 16 jaundiced patients. RESULTS: In the 10 controls, the nine patients with neonatal hepatitis, and the one infant with paucity of intrahepatic ducts, MR cholangiography clearly depicted the gallbladder and common hepatic and common bile ducts. MR cholangiography was 100% accurate in excluding biliary atresia as the cause of neonatal cholestasis, while 99mTc disofenin cholescintigraphic findings were false-positive in four of 10 patients with nonobstructive cholestasis. CONCLUSION: MR cholangiography can be used to depict the major biliary structures of neonates and small infants and to exclude biliary atresia as the cause of neonatal cholestasis by allowing visualization of the biliary tract.

Biliary Atresia↗

PubMed1999

Gd(DTPA-BBA) as a contrast agent in magnetic resonance imaging in rats.

Gadolinium (III)-di(benzyl carbamoylmethyl) diethylenetrinitrilotriacetic acid [Gd(DTPA-BBA)] is a newly developed paramagnetic complex designed for use as a hepatobiliary-specific contrast agent. The purpose of this study was to examine the relaxivity, biodistribution, and magnetic resonance (MR) imaging characteristics of Gd(DTPA-BBA) in rats. Our results showed that the T1 relaxivity of Gd(DTPA-BBA) (3.89 dm3/mmol/s in aqueous solution) was similar to that of Gd(III) diethylenetriamine-pentaacetate [Gd(DTPA)]2- (4.08 dm3/mmol/s) and Gd(III) benzyloxypropionicte-traacetate [Gd(BOPTA)]2- (4.40 dm3/mmol/s). Biodistribution studies indicated that Gd(DTPA-BBA) exhibited hepatobiliary and urinary elimination. In MR imaging studies, Gd(DTPA-BBA) provided biphasic enhancement of normal liver parenchyma, which was characterized by an initial steep increase in enhancement followed by a plateau. The initial relative enhancement (RE%) of the liver, at 1 minute after administration of 0.2 mmol/kg Gd(DTPA-BBA) was 113 +/- 19. The plateau RE% of the liver (48 +/- 13) occurred within 10 minutes and persisted for at least 60 minutes after injection of the contrast agent. In addition, Gd(DTPA-BBA) provided better RE% of the liver than [Gd(DTPA)]2-. The contrast RE% of liver abscess capsules reached a plateau within 5 minutes after injection of 0.1 mmol/kg Gd(DTPA-BBA). Although the hepatic enhancement of Gd(DTPA-BBA) was inferior to that of [Gd(BOPTA)]2-, the results suggest that Gd(DTPA-BBA) has potential as an MR contrast agent for nonspecific and hepatobiliary uses.

Animals↗

PubMed1999

Development of adenoids: a study by measurement with MR images.

Magnetic resonance (MR) imaging, which is able to demonstrate the actual size of adenoids by differentiating them from other soft-tissue structures, can be effectively used to study the normal development of adenoids. To assess the normal development of adenoids and to understand their role in the nasopharyngeal airway compromise, the adenoids of 290 children who had MR examination for other reasons were measured by midsagittal T1-weighted spin-echo MR image. The maximal thickness of adenoids (A), anteroposterior depth of the nasopharynx (N) and the adenoid-nasopharynx (A/N) ratios were obtained using this method. The results showed that of the infants under the age of 3 months only 2 out of 11 adenoids (18%) could be identified. By 4 months of age, adenoids could be identified in 6 of 8 infants (75%). After 5 months of age, all adenoids were well demonstrated by MR imaging. The adenoids developed rapidly during infancy and reached a plateau between 2- and 14 years of age with a mean thickness ranging from 10.7 to 12.2 mm. Finally, the adenoids regressed rapidly after 15 years old. The A/N ratios, which could be used to assess the airway compromise, had a plateau between 2- and 7 years of age. After that, with the steady growth of the nasopharynx, the possible role of adenoid in airway compromise will become increasingly less significant in later childhood.

Adenoids↗

PubMed1999

Diagnostic efficacy of non-breath-hold magnetic resonance cholangiopancreatography.

Magnetic resonance cholangiopancreatography (MRCP) is an emerging imaging technique for direct visualization of biliary and pancreatic ducts without the need for an invasive procedure, ionizing radiation, or iodine contrast media administration. The purpose of this study was to evaluate the efficacy of non-breath-hold MRCP in depicting normal and diseased biliary and pancreatic ducts. A retrospective analysis of 162 patients who underwent MRCP was performed, and a comparison between MRCP and direct cholangiography was made. The overall accuracy of MRCP in diagnosing malignant and benign pancreaticobiliary diseases was also calculated. MRCP depicted more than three hepatic segments in 99% of patients with dilated intrahepatic ducts and in 63% of patients with nondilated intrahepatic ducts. MRCP demonstrated the main hepatic duct, gallbladder, and cystic duct in 100%, 89%, and 72% of patients, respectively. The dilated extrahepatic duct, nondilated extrahepatic duct, dilated pancreatic duct, and nondilated pancreatic duct were visualized in 100%, 98%, 95%, and 77% of patients, respectively. The accuracy of MRCP in diagnosing hepatolithiasis, cholecystolithiasis, and choledocholithiasis was 96%, 97%, and 96%, respectively. The obstruction levels and characteristics determined by MRCP were in agreement with those determined from direct cholangiography in 98% of malignant obstructions and 89% of benign obstructions. The overall accuracy of a combination of MRCP and conventional magnetic resonance imaging in diagnosing pancreaticobiliary diseases was 81% for malignant diseases, 86% for benign diseases, and 82% for stone diseases. We conclude that non-breath-hold MRCP can reliably depict normal and diseased pancreaticobiliary ducts except for cystic ducts and nondilated pancreatic ducts.

Adolescent↗

PubMed1998

Etiology, timing of insult, and neuropathology of cerebral palsy evaluated with magnetic resonance imaging.

To define the patterns of pathologic changes in cerebral palsy (CP) and to assess the etiology and time of brain damage, we reviewed the magnetic resonance images and clinical records of 86 pediatric CP patients seen over 8 years. Patients were divided into two groups, based on the gestational age at birth. The majority of CP patients (69) had spasticity. In the premature group (< 37 wk gestational age) n = 27), spastic diplegia (12 patients) and quadriplegia (8) were the major subtypes. In the term group (> or = 37 wk gestational age) ( n = 59), spastic hemiplegia (23) and quadriplegia (12) were most common. The other main clinical manifestations in the two groups were seizures (36) and mental retardation (15). Magnetic resonance (MR) imaging provided significant findings in 82 patients (95%). In the 27 patients born prematurely, MR imaging revealed periventricular leukomalacia (17), multicystic encephalomalacia (3), cortical and subcortical atrophy (4), migration disorders (2), and basal ganglia injury (1). Among the patients born at term, the MR imaging findings were more heterogeneous; they included cortical and subcortical atrophy (17), brain malformations (17), periventricular leukomalacia (6), multicystic encephalomalacia (5), porencephaly (4), hemiatrophy (3), delayed myelination (3), and none (4). MR imaging alone could define the time of brain insults in 73 of our 86 CP patients. Combined with clinical histories, MR imaging could help assess the time of insult in 93% of patients. The brain insults occurred prenatally in 34 of our patients, perinatally in 37, and postnatally in eight. The time of insult could not be determined in six patients. In the premature patients, the insult occurred most frequently perinatally (74%), whereas in the term group it occurred most frequently prenatally (54%). MR imaging was found to be very helpful in the evaluation of the various neuropathologic changes in CP, in the depiction of the etiology, and in the determination of the time of brain injury.

Adolescent↗

PubMed1998

Magnetic resonance images of neuronal migration anomalies.

Neuronal migration anomalies are a spectrum of brain malformations caused by insults to migrating neuroblasts during the sixth week to fifth month of gestation. To study the characteristics of MRI findings in migration anomalies, MR images of 36 patients (28 children and 8 adults) with migration anomalies were evaluated. Five patients had lissencephaly, eight had pachygyria, twelve had schizencephaly, six had heterotopias of gray matter, three had hemimegalencephaly, and two had polymicrogyria. The frequency of migration anomalies was 0.51% of all cranial MRI studies and 1.21% of pediatric cranial MRI studies at our hospital. The major clinical presentations of these patients were seizure (64%), development delay (42%), motor deficits (42%) and mental retardation (25%). Twenty-five patients (69%) associated with other brain anomalies, including: other migration anomalies in 12 cases (33%), absence of the septum pellucidum in 10 cases (28%), Dandy-Walker malformation/variant in 5 cases, arachnoid cyst in 4 cases, agenesis of the corpus callosum in 3 cases, holoprosencephaly in 2 cases, mega cisterna magna in 1 case and cephalocele in 1 case. Some of them presented with multiple complicated anomalies. As MR imaging provides superb gray-white matter distinction, details of cortical anatomy and multiplanar capability, it can clearly delineate the detail morphologic changes of the brain caused by neuronal migration disorders as well as the associated anomalies.

Adolescent↗

PubMed1997

Preclinical evaluation of Fe-(5-C2H5-EHPG)- as a contrast agent in MR imaging of hepatobiliary system.

Iron(III)-N, N'-ethylenebis[2-(2-hydroxy-5-phenyl)glycine] [Fe-(5-C2H5-EHPG)-] is a paramagnetic complex designed for use as a hepatobiliary agent. Test procedures included synthesis, characterization, toxicity evaluation, biodistribution and experiments for animal MR images. The dose of LD50 in acute toxicity test of Fe-(5-C2H5-EHPG)- in mice was 3.49 mmol/kg. 111In-(5-C2H5-EHPG)- biodistribution studies revealed that the activities were (4.78 +/- 0.97, 5.34 +/- 0.91, 4.53 +/- 0.35)%ID and (0.88 +/- 0.18, 0.99 +/- 0.17, 0.84 +/- 0.06)%ID/gm in the liver at time intervals of 10, 30 and 60 minutes after injection; (5.76 +/- 0.15, 5.75 +/- 0.15, 4.00 +/- 0.04)%ID and (0.49 +/- 0.03, 0.49 +/- 0.05, 0.34 +/- 0.01)%ID/gm in the blood; (1.27 +/- 0.91, 1.46 +/- 1.00, 1.52 +/- 0.46) %ID and (0.89 +/- 0.17, 1.02 +/- 0.18, 1.06 +/- 0.08)%ID/gm in the kidneys, respectively. The results of image enhancement correlated well to the biodistribution. Analysis of the MR images showed degrees of maximal parenchymal % increase of signal to noise ratio (S/N) was 42.09 +/- 3.59% for normal liver at 30 minutes postinjection, which exceeded the value of pathologic liver with bile duct obstruction 16 hours 17.26 +/- 6.6 %, 1 week 19.80 +/- 6.46% and 4 weeks 32.20 +/- 9.01%, respectively, and acute hepatitis 16.50% +/- 4.02%. Persistent enhancement plateau was documented up to 60 minutes after injection and normalized to precontrast value within 22 hours. The common duct was opacified at 10-15 minutes after injection of contrast agent. These results indicated that the Fe-(5-C2H5-EHPG)- could be rapidly extracted from the blood stream by the hepatocytes and excreted into the bile duct. The initial evaluation of Fe-(5-C2H5-EHPG)- demonstrated that Fe-(5-C2H5-EHPG)- was well suited for enhancement of normal liver parenchyma and was compromised with deterioration of liver function. However, the increase of the liver intensities in the animal model of the total biliary obstruction group normalized to precontrast value within 22 hours, which indicated that renal clearance as an effective alternative pathway for biliary excretion. In conclusion, these results indicate that Fe-(5-C2H5-EHPG)- has the potential of becoming a safe and reliable magnetopharmaceutical for the hepatobiliary system.

Animals↗

PubMed1993

MRI demonstration of peritoneal ligaments and mesenteries.

The normal appearances of 14 peritoneal ligaments and mesenteries were demonstrated by magnetic resonance imaging (MRI). Antegrade or retrograde air introduction was employed to distend and mark the gastrointestinal tract. Delineation of these ligaments and mesenteries was helped by the presence of ascites and air-distended bowel loops. The different intraperitoneal compartments are also demonstrated.

Humans↗

PubMed1993

The use of MRI in bowel obstruction.

Nine patients with clinical or radiographic evidences of bowel obstruction were examined by magnetic resonance imaging. Retrograde insufflation of 1000-1200 ml of air through a Foley catheter placed in the rectum was employed. Scopolamine was used to inhibit bowel peristalsis and possibly relax the ileocecal valve. The administered air successfully distended the colon and the small bowel distal to the obstruction in seven of the nine cases. The air-filled small bowel loops were useful in delineating the obstruction sites and adjacent lesions in these seven cases. The diagnosis was established by means of surgery in six cases and by clinical course in three cases. The causes of obstruction included four peritoneal carcinomatoses, and one each of supravesical hernia, intussusception, adhesive band, benign granulomatous stricture, and radiational stricture. The site of obstruction was the distal small bowel in eight cases, and the rectosigmoid colon in one case.

Female↗

PubMed1993

Abdominal MR imaging following antegrade air introduction into the intestinal loops.

Air was used to distend the gastrointestinal tract and act as a contrast medium to effectively delineate the other abdominal organs/masses and to outline intraluminal or mural lesions. We used a nasogastric tube to introduce air into the stomach. Metoclopramide was administered to propel air throughout the gastrointestinal tract. Bowel peristalsis was then controlled by scopolamine butylbromide. Most of the alimentary tract could be distended by air. The normal bowel walls were barely visible between intraluminal signal-void air and extraluminal high-signal fat. Intraluminal tumor, wall thickening, and adjacent structures could be clearly delineated.

Adolescent↗

PubMed1993

Retrograde air insufflation in MRI: a technical note.

Retrograde air insufflation was employed to distend the colon and the ileum in 18 patients and five volunteers for magnetic resonance examination. Good and moderate marking of the ileum was obtained in 18 cases. The colon was nearly completely distended in every case. Intraluminal tumor, mural thickening, and extraluminal lesion were outlined by intraluminal air and surrounding air-distended bowel. This study shows that retrograde air insufflation is a useful method to mark the colon and most parts of the ileum.

Adult↗

PubMed1993

Duchenne muscular dystrophy: MR grading system with functional correlation.

The pelvic girdle, thigh, and calf muscles of 29 patients with Duchenne muscular dystrophy (DMD) were evaluated with magnetic resonance (MR) imaging. The muscles that were most resistant to disease were the gracilis, followed by the sartorius, semitendinous, and semimembranous. Sixteen patients had asymmetric involvement in part of the muscle bundles of thigh. An MR grading system was developed to assess the number of preserved pelvic and thigh muscles, the severity of fatty infiltration of the calf, and the increase of subcutaneous fat. Statistically significant correlations were obtained between MR grade and clinical functional grade (P < .01), MR grade and disease duration (P < .01), and MR grade and patient age (P < .01). An inverse correlation was observed between the creatine kinase values and the MR grade (P < .05). The MR grading system helped identify disease severity in patients with low clinical functional grades. Twenty-four follow-up studies were performed in 22 patients. In 13 of the 24 cases, the MR grade progressed while the clinical functional grade remained unchanged. Both the MR and clinical functional grades progressed in six cases. The results suggest that MR imaging may be useful in prebiopsy mapping and may help accurately monitor the progression of DMD.

Adolescent↗

PubMed1993

Fe(III)-EHPG and Fe(III)-5-Br-EHPG as contrast agents in MRI: an animal study.

The development of specific agents for hepatobiliary magnetic resonance imaging (MRI), iron (III) ethylenebis-(2-hydroxyphenylglycinate) [Fe(EHPG)-] and its derivative iron (III)-N, N' ethylenebis[5-bromo-2-hydroxyphenyl)-glycinate] [Fe(5-Br-EHPG)-] was investigated. Test procedures included method of synthesis, identification, and a test for purity, lipophilicity, toxicity, relaxivity, biodistribution and animal MRIs. Free EHPG and free Fe3+ were undetectable in the purity test. The partition coefficient for the lipophilicity of Fe(EHPG)- was 0.007 and for Fe(5-Br-EHPG)- it was 1.785. The acute toxicity test of Fe(EHPG)- in mice revealed that the LD50 dose of Fe(EHPG)- was 8 mmol/kg. Their relaxivity values were 1.167 and 0.780 s-1mM-1 in an agarose gel system and 1.313 and 0.725 s-1mM-1 in an aqueous solution, respectively. Biodistribution was performed with 59Fe(EHPG)- in anesthetized dogs. There was 1.097% to 1.19% contrast excretion through the opened common bile duct and 54.29% to 61.45% through the urinary tract in a six-hour period. After six hours, the residual contrast agent was only evident in the kidney and liver. The MRIs of dogs with intravenous contrast administration showed significant opacification of the common bile duct within a 10-minute period. Complete opacification of the biliary system could be identified within 1.5 hours. There was no significant difference in the enhancement effect between the inversion recovery sequence and T1-weighted spin echo sequence. The change in signal intensity of the hepatobiliary system on MRIs was similar between Fe(EHPG)- and Fe(5-Br-EHPG)-. The recommended administration dose was 0.083 mmol/kg for both contrast agents.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

MRI manifestations of peritoneal carcinomatosis.

Three cases of proved peritoneal carcinomatosis were examined by magnetic resonance imaging (MRI). Air was used to distend the entire gastrointestinal tract via an antegrade method. The findings included seedings along the small intestine, transverse and sigmoid colon, stellate pattern in the mesentery, plaque-like and bulky tumor masses in the mesentery and greater omentum, and focal thickenings along the right subdiaphragmatic parietal peritoneum. Stenosis caused by tumor encasement at the duodenojejunal junction and ileocolic anastomosis were first detected by MRI and later confirmed by barium studies. Ascites was present in all cases. One case showed ascites located only along the left paracolic gutter. This report shows that MRI is also able to demonstrate peritoneal carcinomatosis by using air as a gastrointestinal contrast medium.

Adenoma, Bile Duct↗

PubMed1989

[Pulmonary artery sling: diagnosis by magnetic resonance imaging--one case report].

Pulmonary artery sling is an uncommon congenital vascular anomaly, which may cause significant respiratory morbidity resulting from an external tracheal compression during early infancy. This condition should be considered on finding a mass interposed between the trachea and the esophagus showing an anterior indentation on the esophagograms. The diagnosis is usually made by invasive methods such as bronchography, bronchoscopy, cardiac catheterization, and angiography. Magnetic resonance imaging (MRI) has now become an excellent method for diagnosing cardiovascular anomalies, but the use of MRI as a means of diagnosing pulmonary artery sling is rare. In 1988, Malmgren et al, first reported the use of MRI in three cases. Their findings suggested that two overlaping sets of axial sections might be necessary for depicting the anomaly because different parts of the left pulmonary artery are imaged in different slices. In this paper, we report a diagnostic scan image which utilizes a single axial scan and reveals the pulmonary artery sling arising aberrantly from the right pulmonary artery. We also found (a) when the pulmonary artery sling interposed between the esophagus and trachea; the trachea become stenotic below the upper one-third in LAO equivalent sagittal section; (b) the right pulmonary artery compresses the proximal part of right pulmonary bronchus, and the right upper lobe bronchus arises from the trachea independently in the coronal section. Thus, we conclude that MRI, if available, should be the first choice modality for further examination when a pulmonary artery sling is suggested by conventional radiography.

Female↗

PubMed1989

Ultrasonography and 99mTc-DISIDA cholescintigraphy in the diagnosis of choledochal cyst in children.

Eighteen children with choledochal cyst have underwent abdominal ultrasonography and 99mTc-DISIDA (di-isopropylphenylcarbamoyl-methylimidodiacetic acid) cholescintigraphy before surgery. All patients had typical sonographic findings of a large cystic mass in the porta hepatis with direct continuity to the biliary system. The gallbladder could be easily recognized and distinguished from the cystic mass in every except one case. Dilatation of the intrahepatic ducts was noted in 12 patients (67%). Coexisting biliary stones were found in 3 patients (17%). On the cholecintigrams, 14 patients (78%) had characteristic findings of a round or ovoid photon-deficient area in the porta hepatis with delayed filling and stasis of the tracer in the same area. Three infants (17%) showed a persistent round photon-defect over the porta hepatis without visualization of gallbladder or bowel radioactivity, which was thought to suggest a choledochal cyst with obstruction. A combination of ultrasonography and cholescintigraphy can provide a very accurate preoperative diagnosis of choledochal cyst.

Bile Ducts↗

PubMed1984

Diagnosis of obstructive jaundice in infants: Tc-99m DISIDA in duodenal juice.

Technetium-99m di-isopropylphenylcarbamoylmethylimidodiacetic acid cholescintigraphy, together with measurements of radioactivity in duodenal juice, was used to evaluate 23 infants with prolonged obstructive jaundice. Four patients proved to have biliary atresia. The remainder had neonatal hepatitis. There was distinct differentiation of biliary atresia from neonatal hepatitis when the time-activity curves were analyzed. In neonatal hepatitis the radioactivity in duodenal juice is obviously higher, peaking above 1500 cpm/100 microliter per mCi dose. In biliary atresia the pattern is flattened, with maximal activity below 500 cpm/100 microliter per mCi dose.

Bile Ducts↗

PubMedDate not supplied

MRI manifestations of gastrointestinal lymphoma.

The magnetic resonance (MR) images of 11 cases of gastrointestinal lymphoma are presented. The findings include irregularly thickened mucosal folds, irregular submucosal infiltration, annular constricting lesion, exophytic tumor growth, mesenteric masses, and mesenteric/retroperitoneal lymphadenopathy. The tumors were homogeneous and intermediate in signal intensity on T1-weighted images. Heterogeneously increased signal intensities were noted on T2-weighted images. There was mild to moderate enhancement after intravenous administration of gadolinium dimeglumine (Gd-DTPA). The submucosal tumor infiltration might be outlined between the strongly GD-DTPA-enhanced mucosa and the low-intensity muscular layer. In one case that received tumor resection, the pathological examination showed destruction of most parts of the muscular layer, and the MR images did not disclose the low-intensity muscular zone.

Adolescent↗