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ABSTRACT: This study was undertaken to evaluate the sonographic measurement of subarachnoid spaces in normal children and its relationship with age and to define a normal range in a Chinese population and to differentiate normal variant findings from pathologic dilatation. The subarachnoid spaces in 278 normal term neonates, infants, and children were studied with real-time ultrasound using a 7.5-MHz vector transducer. The craniocortical width, sinocortical width, and interhemispheric width were measured in the coronal plane at the level of the foramen of Monro, on either side of the hemispheres. Correlation of sonographic measurements with age was made. The mean widths were plotted against age. A correlation with age was found in all three spaces, with an increasing trend with age until 28 weeks of gestation. Thereafter, a decreasing trend was noted. The normal upper limit of subarachnoid spaces for children is proposed to be the values on the ninety-fifth percentile of the regression curve. Correlation of measurement with age must be considered to decide whether an increase in subarachnoid space is pathologic or not.
Pediatric Neurology 12/2001; 25(5):380-4. · 1.52 Impact Factor
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ABSTRACT: Neurovascular contact (NVC) with the root exit zone (REZ) of the ipsilateral facial nerve is associated with hemifacial spasm (HFS), but unresolved issues remain.
To 1) determine the frequency of symptomatic and nonsymptomatic NVC, 2) determine the features of NVC associated with HFS, and 3) correlate severity of HFS to these features.
Two independent, blinded, prospective assessments of high-resolution MR and MR angiography (MRA) images were performed on Chinese cases (HFS: n = 44; age-matched control subjects: n = 20).
Over 88% of 44 symptomatic sides in patients with HFS had NVC of the ipsilateral facial nerve. At least 80% of symptomatic sides involved NVC at the anterior aspect of the REZ [REZ(ant.)]. Although NVC was observed in approximately half of nonsymptomatic sides, at least 70% of them were not at REZ(ant.). NVC at the cisternal and intracanalicular portions of the facial nerve were not associated with HFS. Half of our patients with HFS had bilateral NVC, but none had bilateral symptoms. Most of our MR/MRA images showed that the size and position of the arterial branches of the vertebrobasilar system were markedly asymmetric. Of patients with bilateral NVC, over 83% had asymmetric NVC sites. The anterior inferior cerebellar artery was the most common vessel involved in NVC, but was not significantly associated with HFS. Most of the NVC involved one vessel at one contact point with no indentation. The development of HFS was significantly associated with nerve indentation in NVC. The development and severity of HFS were not associated with multiple contact points in NVC. No significant interobserver variability existed between the blinded assessments.
MRI/MR angiography are accurate, fast, and safe in characterizing neurovascular contact (NVC) at the brainstem. The site of NVC and ipsilateral facial nerve indentation in NVC are significant determinants for the development of hemifacial spasm (HFS). The lack of bilateral NVC at the anterior aspect of the root exit zone of the facial nerve could explain in part the lack of bilateral symptoms. The development and severity of HFS are not associated with a specific blood vessel or multiple contact points in NVC.
Neurology 01/2000; 53(9):2132-9. · 8.31 Impact Factor
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American Journal of Roentgenology 11/1999; 173(4):985-8. · 2.78 Impact Factor
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ABSTRACT: OBJECTIVE: Our objective is to present the MR appearance of breast paraffinoma, a late complication of breast augmentation by liquid paraffin wax, and to correlate this appearance with the histopathologic findings that were available for three of the 11 breasts we studied. CONCLUSION: Breast paraffinomas have a characteristic MR appearance that correlates well with histopathologic findings. With MR imaging, we were able to visualize the location and extent of the paraffinoma, best seen on the fat-suppression sequence, and to evaluate the surrounding fibroglandular breast tissue.
American Journal of Roentgenology 11/1999; 173(4):929-32. · 2.78 Impact Factor
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ABSTRACT: In a phase IIIb clinical trial of the ultrasound contrast agent Levovist (Schering AG, Berlin, Germany), the role of Levovist in the management of patients with clinically suspected hepatocellular carcinoma (HCC) was evaluated and its efficacy was assessed. The assessment included the duration of diagnostically usable Doppler signal enhancement, and safety and tolerance of intravenous administration. All patients with clinically suspected hepatocellular carcinoma were referred for Doppler sonographic examination over a 5-month period and lesions with absent or suboptimal Doppler signals were included in the trial. A total of 300 mg/mL in concentration (8.5 mL) of Levovist was administered through a peripheral vein while Doppler signal intensity in the lesion, based on a visual score, was recorded. Blood pressure and pulse were recorded before and after injection. Thirty-eight patients were examined, of which 29 were included in the trial. The lesions were subsequently proven histologically to be 19 HCC, one cholangiocarcinoma, two regeneration nodules and one colonic metastasis. For six patients in whom histological proof was not available, the diagnosis of HCC was suggested based on markedly elevated serum alpha-fetoprotein levels. All but one (96%) of the 25 HCC demonstrated increased Doppler signal after Levovist. There were no Doppler signals before and after Levovist injection in three non-HCC lesions (two regeneration nodules and one colonic metastasis). Two patients (6.9%) suffered minor adverse reactions of nausea and vomiting. The results show that Levovist is safe and is able to improve lesion characterization and increase diagnostic confidence of hepatocellular carcinoma by enhancing tumour vascularization Doppler signal intensity.
Australasian Radiology 06/1999; 43(2):156-9. · 0.51 Impact Factor
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ABSTRACT: The ileoileocolic type of childhood intussusception is difficult to diagnose pre-operatively and is associated with increased morbidity. This study describes the clinical and imaging features of 10 consecutive ileoileocolic intussusceptions diagnosed ultrasonically in 10 patients over a 36 month period. Ultrasound-guided hydrostatic reduction using Hartmann's solution was attempted in all 10 patients. Clinical and imaging features were compared with those of 28 ileocolic intussusceptions in 25 patients diagnosed and treated using the same methods during the same period. Most of the clinical and plain radiographic features of the patients with the ileoileocolic and ileocolic types of intussusception were similar. The two types of intussusception had the classical doughnut or pseudokidney, or both, signs on pre-reduction ultrasound scans. During the reduction process, when surrounded by fluid within the caecal lumen, the ileoileocolic type of intussusception had a typical complex appearance due to frond-like loops of intussuscepted small bowel. This finding was present in all cases. The hydrostatic reduction rate was only 10% (1/10) for ileoileocolic intussusception, compared with 92.9% (26/28) for the ileocolic type. All unsuccessfully-reduced cases underwent surgery, with surgical confirmation of the intussusception type in all cases. Only one patient was found to have a lead point, caused by a Meckel's diverticulum. In conclusion, the diagnosis of ileoileocolic intussusception can be made pre-operatively and these patients require surgical management.
British Journal of Radiology 10/1997; 70(837):891-6. · 1.31 Impact Factor
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ABSTRACT: A comparison was made of the efficacy of ultrasound guided Hartmann's solution hydrostatic reduction on 23 patients (US group) with the same number of consecutive patients in whom hydrostatic reduction was done by barium enema (BE group) under fluoroscopy for childhood intussusception. The US group was diagnosed by ultrasound scan and reduction was attempted under the guidance of ultrasonography with Hartmann's solution at 100 mm Hg pressure. Excluded were patients older than 12 years, patients in shock, patients with peritonitis, bowel perforation, and gross abdominal distension as well as recurrent intussusception of more than three episodes. There were three patients excluded in this group. The diagnosis of intussusception and complete reduction were confirmed by gastrografin enema. This US group had three recurrences (3 of 26, 11.5%), one lead point (1 of 23, 4.4%), and 19 successful reductions (19 of 26, 73%). Incidentally, there were also three patients excluded in this period of barium enema reduction. There was only one recurrence (1 of 24, 4.2%), one leadpoint (1 of 23, 4.4%), and 12 successful reductions (12 of 24, 50%) in these 23 BE patients. The success rates for the ileo-colic intussusceptions with Hartmann's solution reduction and barium enema reduction were 91% (19 of 21) and 55% (12 of 22), respectively (P = .00865). There was no complication in either group, and the accuracy of diagnosing a complete reduction was 100% in both forms of reduction. Hence, ultrasound-guided hydrostatic reduction for childhood ileocolic intussusception is preferred because it is safe, accurate, has a higher success rate, and can avoid radiation exposure risk.
Journal of Pediatric Surgery 02/1997; 32(1):3-6. · 1.45 Impact Factor
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ABSTRACT: Currently, the standard methods for therapeutic reduction of intussusception in children involve considerable ionizing radiation. This study tested the effectiveness of sonographically guided hydrostatic reduction of intussusception using Hartmann's solution, a fluid with near-physiologic composition.
Between March 1, 1994, and January 31, 1996, all children clinically suspected of having intussusception were evaluated by sonography. Those with positive findings on sonography were entered into the study and underwent confirmatory sonographically guided meglumine diatrizoate enema. During continuous sonographic monitoring, we used Hartmann's solution for attempted reduction of intussusception. Criteria for successful reduction were disappearance of the intussusceptum and passage of fluid through the ileocecal valve. Another sonographically guided meglumine diatrizoate enema was used to confirm successful reduction.
We detected 25 consecutive intussusceptions in 22 patients. The patients were 12 girls and 10 boys, with a mean age of 14 months (range, 1-72 months). Sonograms revealed in all patients doughnut or pseudokidney signs or both. The sites of intussusception were the transverse colon (17 of 25), hepatic flexure (4 of 25), ascending colon (2 of 25), splenic flexure (1 of 25), and descending colon (1 of 25). Other findings were dilated fluid-filled small bowel (11 of 25) and free intraperitoneal fluid (9 of 25). The success rate of our sonographically guided attempts at hydrostatic reduction was 76% (19 of 25). Success was proven by meglumine diatrizoate enema in all 19 patients. The mean time of the reduction procedure was 18 min (range, 2-45 min). No complications occurred. All six patients in whom hydrostatic reduction was unsuccessful underwent surgery. Five of these patients had ileoileocolic intussusceptions. On sonography, when surrounded by fluid, ileoileocolic intussusceptions had a typically complex, fronded appearance. The remaining patient in whom hydrostatic reduction was unsuccessful had ileocolic intussusception. Of six ileoileocolic intussusceptions, one was hydrostatically reduced and a second was converted into an ileoileal intussusception before requiring surgery. The other four intussusceptions were surgically treated.
Our data suggest that sonographically guided hydrostatic reduction with Hartmann's solution can be used to treat ileocolic intussusception and to diagnose ileoileocolic intussusception.
American Journal of Roentgenology 12/1996; 167(5):1237-41. · 2.78 Impact Factor
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ABSTRACT: The Triple A syndrome is a rare condition comprising achalasia, alacrima and adrenocorticotrophic hormone (ACTH) insensitivity. A 12 year old Chinese girl with a variant of this syndrome (achalasia and alacrima), presenting with failure to thrive, is reported. Typical appearances of achalasia on barium swallow subsequently led to the correct diagnosis. The radiologist may be the first to recognize this syndrome and hence help anticipate its potentially life-threatening sequelae.
Australasian Radiology 09/1994; 38(3):222-4. · 0.51 Impact Factor
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British Journal of Radiology 06/1993; 66(785):471-4. · 1.31 Impact Factor
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Clinical Radiology 06/1992; 45(5):360; author reply 361. · 1.95 Impact Factor
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ABSTRACT: In 137 normal CT scans of the nasopharynx, the parapharyngeal spaces at the nasopharynx level were asymmetrical in 30%. Their difference in width and distance from the midline was greater than 1 mm in 51% and 44% respectively. Fat was absent in the interpterygoid fascia in 20%, in the alar fascia in 28%, in the prevertebral space in 35%, and in the retropharyngeal space in 99% of patients. Assessment of tumour extension to the paranasopharyngeal space usually relies on symmetry and fascial fat planes. As either feature may not be present in the normal person, the relation of the tumour to two lines representing two fascial planes is proposed as a complementary method for the evaluation of tumour extension.
Clinical Radiology 03/1992; 45(2):109-13. · 1.95 Impact Factor
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ABSTRACT: Biliary cystadenoma and cystadenocarcinoma are rare tumours which have a good prognosis after complete surgical removal. Correct pre-operative diagnosis depends on the imaging characteristics of the tumours. We have observed some unusual features including multifocal tumours with attachment to other abdominal organs, tumour presenting as cholangitic abscess, and distant metastasis after apparently complete resection by hemihepatectomy.
Clinical Radiology 04/1991; 43(3):183-5. · 1.95 Impact Factor
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ABSTRACT: The use of computed tomography (CT) was investigated in 50 patients with recurrent pyogenic cholangitis, 22 of whom had undergone prior choledochoenterostomy or sphincteroplasty. A spectrum of pathologic features was noted, including intrahepatic ductal dilatation (n = 50), common duct dilatation (n = 34), strictures (n = 11), intrahepatic calculi (n = 37), common duct calculi (n = 15), pneumobilia (n = 26), segmental atrophy (n = 18), and splenomegaly (n = 7). Unilobar disease existed in 14 patients. The left lateral segment was predominantly affected, with ductal dilatation (n = 23) and segmental atrophy (n = 13). During acute exacerbation, additional manifestations were observed: ductal wall enhancement (n = 4), segmental parenchymal enhancement (n = 9), hepatic abscess (n = 9), and biloma (n = 2). CT enables sensitive, complete evaluation of this disorder. It is valuable when results of ultrasonography are non-diagnostic and for planning hepatic resection, evaluating associated mass lesions, and guiding complex interventional procedures.
Radiology 02/1989; 170(1 Pt 1):165-9. · 5.73 Impact Factor
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ABSTRACT: Fifty cases of recurrent pyogenic cholangitis among Chinese in Hong Kong were studied by ultrasound and compared with endoscopic retrograde cholangiopancreatography. The sensitivity of ultrasound detection of both dilated intrahepatic biliary ducts and intrahepatic calculi is 67% as compared with endoscopic retrograde cholangiopancreatography. A negative study, therefore, does not rule out the presence of such pathological features. A dilated common duct is present in virtually every case of recurrent pyogenic cholangitis and ultrasound is very accurate in its detection. Furthermore, ultrasound is able to provide additional information which can be missed with endoscopic retrograde cholangiopancreatography. Prominent periportal echogenicity, concomitant abscesses and tumours are examples in this series. Such findings bear significance on the management of patients with recurrent pyogenic cholangitis.
Clinical Radiology 02/1987; 38(1):79-85. · 1.95 Impact Factor
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ABSTRACT: Prominent periportal echogenicity was detected during sonographic examination of patients suffering from recurrent pyogenic cholangitis, hepatocellular carcinoma and acute cholecystitis. To document the finding, 140 normal individuals were studied to establish a norm for the evaluation of the periportal echogenicity. The significance of this sonographic finding and its possible aetiology are discussed.
British Journal of Radiology 07/1986; 59(702):543-6. · 1.31 Impact Factor
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P L Khong,
W C Peh,
C H Lam,
K L Chan,
W Cheng,
W W Lam,
V H Ai,
H Saing,
P K Tam, L L Leong,
L C Low
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ABSTRACT: The authors review the technique of ultrasound-guided hydrostatic reduction of childhood intussusception and illustrate, in real-time fashion, the treatment of three cases with this technique. Two cases of successful reduction of ileocolic intussusception are demonstrated. The third case is an example of the complex fronded appearance of ileo-ileocolic intussusception and failed reduction. This technique is recommended as an alternative method for the treatment of childhood intussusception, as it does not involve ionizing radiation and is a simple and safe procedure.
Radiographics 20(5):E1. · 2.85 Impact Factor
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ABSTRACT: Hepatolithiasis is a primary disease of the biliary ducts, presenting with recurrent pyogenic cholangitis, complicated by parenchymal infection, obstructive cholangiopathy and subsequent parenchymal destruction. Cholangiocarcinoma is a rarer complication. Modern imaging aims at accurate delineation of biliary ducts and liver parenchyma. It directs planning of surgical or interventional treatment, and serves to guide these procedures. The characteristic features comprise varying combinations of ductal dilatation, intrahepatic/extrahepatic ductal stones, segmental ductal strictures and lobar/segmental atrophy; and in acute exacerbation parenchymal or ductal contrast enhancement, abscess and biliary obstruction. Ultrasonography is the preferred primary examination. Further imaging depends on the ultrasonography findings, the patient's symptomatology, the clinical problems and the intended mode of treatment. Contrast cholangiography is warranted preceding biliary intervention. Computed tomography evaluates ductal stones, extent of disease, acute parenchymal complications and prior to hepatic resection. Magnetic resonance imaging is less accessible, but obtains cross-sectional findings similar to computed tomography. It comprehensively evaluates the liver and portal venous system, for prognostic indication and contemplation of liver resection. For diagnostic purposes, magnetic resonance cholangiography promises to replace the more invasive contrast cholangiography. Therapeutic approaches tailored to the results of strategically applied imaging helps to improve the outcome of patients with hepatolithiasis.
Hepato-gastroenterology 44(14):358-69. · 0.66 Impact Factor
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ABSTRACT: Spinal cord ganglioglioma is a rare tumor most often encountered in the first three decades. Scanty computed tomography (CT) reports on the tumor describe it as a hypodense or cerebrospinal fluid (CSF) dense area with little contrast enhancement despite its solid nature. We report two cases of spinal ganglioglioma both involving almost the whole spinal cord. On magnetic resonance imaging (MRI), the tumors appear hypointense to the spinal cord on T1 and hyperintense to the cord on T2 images, and were mainly solid at exploration. It is important to recognize these tumors as long survival can be achieved after surgical resection.
Clinical Imaging 15(2):109-12. · 0.75 Impact Factor
