Biomedical subjects

G C Liu

Publications and source records attributed to G C Liu.

At least 55 records · Page 3Linked to original sources

PubMed1995

Computed tomography and magnetic resonance imaging of intracranial ependymomas.

We evaluated the neuroimages of 18 pathologically proven cases of ependymoma, 15 cases by CT evaluation and 9 cases by MRI evaluations. In 7 cases of supratentorial ependymomas, 4 were intraparenchymal and 3 were intraventricular ependymomas originating from the ependymal lining layer, the floor of the lateral ventricle, which was best demonstrated on a sagittal MR image. For the cases of infratentorial ependymomas, all were intraventricular. Evidence of seeding through the cerebrospinal fluid pathway to the basal cisterns, spinal cord or ventricles was presented in 6 cases which were particularly well demonstrated in the sagittal section with gadolinium-DTPA enhanced MR imaging. On CT scan, isodense tumors with various portions of high enhancement within a moderate enhancement mass were the most frequent features. In MRI, isointensity relative to gray matter on T1-weighted images and hyperintensity on mild and heavy T2-weighted images were most frequently seen. The signal heterogeneity representing soft tissue, small cysts, necrosis, calcification, vessels or hemosiderin was better visualized in MRI which offered a better assessment of the character of tumor compositions. The soft tissue mass, calcification and cysts as revealed in both CT and MRI are nonspecific, but the location, ages, CSF seeding and particularly, superior MR images can offer very important clues for the diagnosis of ependymoma.

Adolescent↗

PubMed1994

Rhinocerebral mucormycosis in IDDM. Sequential magnetic resonance imaging of long-term survival with intensive therapy.

OBJECTIVE: To describe the clinical course and the utility of computerized tomography (CT) and magnetic resonance imaging (MRI) in the successful management of an often fatal fungal infection in a 12-year-old patient with insulin-dependent diabetes mellitus (IDDM). CASE: The patient was admitted to The University of Mississippi Medical Center (UMC) for the purpose of diabetic ketoacidosis (DKA) management and subsequent intensive therapy for mucormycosis according to nationally accepted standards of care. Strict diabetic control was instituted with frequent monitoring of blood glucose levels and interval assessment of HbA1c. Sequential MRI studies were obtained according to approved patient standards; the clinical and MRI course of the infection was charted. RESULTS: The patient's DKA resolved within 12 h on intravenous fluid repletion and insulin therapy. His sinusitis/rhinitis noted on admission did not respond to intravenous antibiotic therapy and progressed with obvious left orbital involvement and left cranial nerve palsies by 72 h of hospitalization. CT and MRI were invaluable aids to the early diagnosis and design of appropriate surgical and antifungal management of this patient, who survived with minimal left cranial nerve palsies. CONCLUSIONS: Our patient is among the youngest of IDDM patients reported to have survived rhinocerebral mucormycosis. His survival is attributed to early recognition of possible mucormycosis with diagnostic support of CT and MRI, surgical debridement and antifungal therapy, and intensive blood glucose control. Sequential MRI is invaluable to the design of therapy for this type of patient and shows the nearly 3-year recovery from mucormycosis.

Brain Diseases↗

PubMed1994

Imaging diagnosis of cavernous hemangioma of the rib--one case report and review of the literature.

Osseous hemangioma is a benign neoplasm, rarely located in the ribs. A 56-year-old female patient without specific complaint had a large extrapleural lesion on chest posteroanterior radiograph. Expansile destruction of left seventh rib and relatively fine trabeculation were noticed in the mass from plain roentgenogram and computed tomography (CT). Contrast enhancement in noncalcified component of the lesion was revealed. Pleural effusion, lung parenchymal or mediastinal abnormality were not identified. Resection of the lesion with part of the originating rib was carried out. The pathologic diagnosis was cavernous hemangioma. We present a case with a large rib hemangioma which often leads to difficulty in radiologically differential diagnosis with other common malignant rib tumors. We also review the literature about hemangioma and malignant neoplasms of the ribs.

Bone Neoplasms↗

PubMed1994

MRI manifestations of leptomeningeal metastasis.

Twenty-six cases with leptomeningeal metastasis were analyzed and Gd-DTPA enhanced MR imaging was found to be the most useful tool for making the diagnosis. The important manifestations in order of frequency were: 1) leptomeningeal enhancement; 2) ependymal enhancement; 3) plaque, nodule or mass in the subarachnoid space or ventricles; 4) nerve root thickening; and 5) ventricular dilatation not related to the obstruction of the primary neoplasm. A review of the literature has shown that intracranial leptomeningeal metastasis from spinal cord astrocytoma are very rare. In our series, 3 cases with primary brain tumors developed spinal subarachnoid involvement. This paper also reviews 1 case with thoracic cord astrocytoma which developed multiple intracranial leptomeningeal metastasis.

Adolescent↗

PubMed1994

Magnetic resonance imaging and computed tomography of transitional cell carcinoma of renal pelvis and ureter.

Fourteen patients with clinically suspicious transitional cell carcinoma of renal pelvis or ureter were preoperatively examined with magnetic resonance imaging (MRI) and computed tomography (CT). All of the cases had surgical approval. In eleven of these patients, the tumor was correctly detected by MRI. Two cases were falsely positive including one squamous cell carcinoma (SCC) and one Wilms' tumor of the kidney. The final case was falsely negative. The positive predictive value of MRI was 92.9%. The sensitivity was 91.7%. In seven of the fourteen patients, the CT findings were truly positive. There were five falsely negative findings and two falsely positive cases. The positive predictive value by CT was 64.3%. The sensitivity was 59.3%. Tumor stagings were done for all patients. The accuracy rate of staging was 7/7 by CT and 10/11 by MRI. MRI showed better identification of distant metastasis in the liver, vertebrae and vascular structure because of its high tissue contrast and larger field of view. MRI had a higher positive predictive rate and sensitivity for identification of uroepithelial tumor than CT.

Aged↗

PubMed1994

MR imaging of sports-related muscle injuries.

Magnetic resonance (MR) imaging of the thighs of 26 baseball athletes and one softball athlete were studied to evaluate muscle injuries. We documented the abnormalities present in MR imaging after a muscle injury and evaluated the role of MR imaging in muscle injuries. Fifteen of the athletes showed muscle abnormalities in MR images. These include muscle strains without tear, muscle tear, scar and chronic tendon injury. Having the advantages of high tissue contrast and multiplanar display capability, MR allowed direct visualization of the injured muscles and characterization of traumatic lesions. We conclude that MR could be a good imaging modality for evaluating muscle injuries.

Adult↗

PubMed1994

[Metastasis involving the leptomeninges and ventricles of the brain--CT evaluation].

The diagnosis of leptomeningeal or ventricular metastasis by cranial computerized tomography (CT) contributes to earlier treatment and sometimes alters the management of patients with intra- or extra-cranial malignancy. In 20 cases whose metastasis were spreaded via CSF seeding, the abnormal CT findings were 1) mass or nodule in the ventricles or subarachnoid space, 2) ependymal, subependymal enhancement, 3) sulcal, gyral or cisternal enhancement, 4) hydrocephalus not related to the obstruction of primary tumor, 5) falx or tentorial enhancement. In another 8 cases, the metastasis developed through hematogeneous spreading to the choroid plexus or paraventricular parenchyma. The mass or nodule within the ventricles could be well identified with enhanced CT scan. The involved ventricles, in order of frequency, were lateral, 3rd, and 4th ventricles in our series.

Adolescent↗

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↗

PubMed1993

The role of ultrasound in scrotal trauma.

We reviewed the sonograms of 16 cases with scrotal trauma and documented the spectrum of abnormalities that may be present in sonography after a scrotal injury. The sonographic findings included scrotal hematoceles, post-traumatic epididymitis, epididymal hematoma, testicular hematoma and/or infarction, testicular rupture, testicular swelling and hyperemia. Ultrasound is able to distinguish intratesticular and extratesticular lesions. The integrity of the testis could be evaluated as well. It should be the imaging modality of choice for the evaluation of scrotal trauma.

Adolescent↗

PubMed1993

MR evaluation of tuberculous spondylitis.

A total of 29 proven tuberculous spondylitis patients underwent MR studies. Gd-DTPA enhancement was performed in 10 patients. Contiguous 2 vertebral involvement, subligamental spread of paraspinal abscesses and cord indentation were observed in 93% of the cases. Destruction of the vertebral body occurred in 76%. Intermediate or low T1 signal intensity and high T2 signal intensity were observed by MR. A combination of these characteristic findings strongly suggests the diagnosis of tuberculous spondylitis. Gd-DTPA administration did not facilitate diagnosis. MR examination should be considered as the main imaging modality for patients with suspected tuberculous spondylitis.

Abscess↗

PubMed1993

Ventricular tumors--CT evaluations of 28 cases.

Ventricular neoplasms can be grouped together as a single disease entity because of the behavior of some of the tumors and similarities between the access of therapy and procedure of operation. In our series, the incidence of various ventricular neoplasms (shown in decreasing order) were metastasis, astrocytoma, ependymoma, meningioma, choroid plexus papillomas and oligodendroglioma. The intraventricular tumors included some metastasis involved by hematogenous spread, meningioms, and choroid plexus papilloma while paraventricular tumors included some of the systemic myeloproliferative disorders with ventricular seeding along with tumors with glial origins. Most of the patients with symptoms of intraventricular tumors also had symptoms related to increased intracranial pressure while those with paraventricular neoplasm presented symptoms related to focal signs or symptoms. CT scan with enhancement could provide a very good image modality except in some involvements in the posterior cranial fossa.

Adolescent↗

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↗

PubMed1992

Spinal muscular atrophy: MR evaluation.

The neurogenic myopathy of spinal muscular atrophy (SMA) is degeneration of anterior horn cells of the spinal cord and associated muscle weakness. In three patients with the severe type, according to Dubowitz's classification, magnetic resonance imaging (MRI) of the lower extremity showed severe atrophy of the entire muscle bundles of the thigh and the calf. Nine intermediate type patients had ragged atrophy of muscle bundles of the thigh and the calf with selective preservation of adductor longus muscle. Five patients with the mild type had fatty infiltration of muscle bundles and increased intermuscular fat planes. MRI was insufficient for the evaluation of cervical cord abnormalities. MRI of the lower extremity was a reliable complementary modality for the diagnosis and follow-up of SMA patients.

Child↗