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Biomedical subjects

C Metreweli

Publications and source records attributed to C Metreweli.

At least 145 records · Page 8Linked to original sources
PubMed1998

Anatomy of the normal brachial plexus revealed by sonography and the role of sonographic guidance in anesthesia of the brachial plexus.

OBJECTIVE: The purpose of this study is to describe the sonographic appearance of the normal brachial plexus and to evaluate the use of imaging guidance for brachial plexus anesthesia. SUBJECTS AND METHODS: Twenty adults requiring upper limb surgery underwent sonography with a high-frequency transducer to identify the brachial plexus at the interscalene (n = 16) and supraclavicular (n = 4) regions. Catheters for brachial plexus anesthesia were placed using sonographic guidance and evaluated using radiography and CT after injection of contrast material. The success of the neural blockade and surgical anesthesia was assessed. General anesthesia was chosen preoperatively or used for supplementation if blockade was incomplete. RESULTS: The brachial plexus appeared as three discrete rounded hypoechoic nodules between the scalenus anterior and medius muscles on transverse sonography at the lower cervical (C6) region, representing the trunks in sagittal oblique section. A cluster of hypoechoic nodules corresponding to the divisions was seen cephalad to the subclavian artery on sagittal scans of the supraclavicular region. Radiography was used to verify correct catheter placement; the brachial plexus sheath appeared as a tubular area of contrast material in the neck that was well circumscribed in patients who had supraclavicular injections of contrast material and corrugated in those who had interscalene injections. CT scans showed contrast material spread around the scalenus muscles in most patients with interscalene injections. Successful neural blockade at 20 min and postoperative analgesia were achieved in all patients. Surgical anesthesia was achieved in nine of 15 patients. Five patients chose general anesthesia before surgery and therefore did not have surgical anesthesia assessed. CONCLUSION: High-resolution sonography can show normal brachial plexus anatomy and facilitate catheter-based brachial plexus anesthesia without complications.

Adolescent↗
PubMed1998

Intraoperative laparoscopic sonography for improved preoperative sonographic pathologic characterization of adnexal masses.

This study compares the diagnostic accuracy of laparoscopic sonography and transvaginal sonography in the evaluation of adnexal masses. Fifty-eight women underwent transvaginal sonography, which showed 69 adnexal masses, and laparoscopic ultrasonography, which showed 68 adnexal lesions. Conventional gray-scale ultrasonography (using transvaginal sonography and laparoscopic ultrasonography) was performed with morphologic characterization of internal architecture, followed by color Doppler imaging with spectral Doppler analysis where possible. A specific diagnosis was obtained with transvaginal sonography and laparoscopic ultrasonography based on a combination of imaging features. The specific diagnosis obtained with each imaging modality was compared with the final histologic diagnosis as the gold standard in 57 patients with 68 adnexal masses who underwent cystectomy or oophorectomy. The ability of laparoscopic sonography to detect the contralateral ovary and any residual ovarian tissue in the presence of a mass was also compared with transvaginal sonography. The accuracy of laparoscopic ultrasonography in the characterization of adnexal masses was 83.8% and that of transvaginal sonography was 73.5% (P < 0.05). Laparoscopic sonography showed greater morphologic detail than that obtained with transvaginal sonography, allowed more precise and specific characterization of adnexal masses, and detected additional adnexal lesions not evident on preoperative transvaginal sonography. Laparoscopic ultrasonography showed the contralateral ovary in 86.2% of patients, compared with 81.0% using transvaginal sonography (P = 0.51). In addition, laparoscopic ultrasonography was able to demonstrate the presence of residual ovarian tissue in the side affected pathologically in 76.5% of patients compared with 59.4% using transvaginal sonography (P < 0.005). Laparoscopic sonography allows more precise morphologic characterization of internal architecture and histologic diagnosis of adnexal lesions, but it is as yet unable to increase the diagnostic accuracy of borderline or malignant lesions, possibly due to the small sample size. Laparoscopic sonography is superior to transvaginal sonography in the evaluation of residual ovarian tissue in the side affected pathologically, which may help in surgical planning between cystectomy and oophorectomy, and also in the identification of the contralateral ovary, which may potentially increase the detection of bilateral pathologic conditions.

Adnexal Diseases↗
PubMed1998

Diagnostic accuracy of sonographic criteria for evaluation of cervical lymphadenopathy.

Although ultrasonographic criteria for abnormal nodes are used routinely in the evaluation of cervical lymphadenopathy, the diagnostic accuracy of these criteria in different areas has not been documented. This study evaluated 977 normal cervical nodes from 80 normal subjects and 1419 abnormal cervical nodes from 277 patients with proven cervical lymphadenopathy. The diagnostic accuracy (sensitivity, specificity, positive predictive value, negative predictive value, and accuracy) of size, shape (short axis to long axis ratio), echogenic hilus, and nodal border for regional lymph nodes are evaluated and discussed.

Adolescent↗
PubMed1998

Nasopharyngeal carcinoma: dynamic MR imaging with gadolinium.

OBJECTIVE: To evaluate the use of enhanced dynamic MR images in nasopharyngeal carcinoma (NPC). METHODS: Dynamic enhanced turbo spin-echo transverse images were obtained in 35 patients with newly diagnosed NPC. Comparison was made between the pre-contrast image, last enhanced scan and dynamic series in assessment of the extent of primary tumor and lymph node involvement. RESULTS: Enhanced MR images improved delineation of tumor in the following regions, nasopharyngeal wall (6/35), levator palatini (44/70), tensor palatini (12/70), prevertebral muscles (3/70), medial pterygoid muscle (7/70), pharyngobasilar fascia (30/35), parapharyngeal fat space (23/70), nasal cavity (33/70), oropharynx (6/35), sphenoid sinus (6/35), maxillary sinus (6/70), ethmoid air cells (14/35), cavernous sinus (5/35), cranial fossa (4/35), clivus (13/35) and pterygoid genu (2/70). Eight of the 9 normal and 79/82 abnormal nodal groups, on conventional imaging criteria, enhanced with the same pattern and intensity as the primary tumor. The dynamic series did not improve delineation of tumor extent in comparison with that obtained on last enhanced image. CONCLUSION: Enhanced MR images are valuable in evaluating the extent of primary tumor. Dynamic imaging was of no additional benefit in the evaluation tumor extent.

Adult↗
PubMed1998

Head and neck lipomas: sonographic appearance.

PURPOSE: The diagnosis of cervical lipoma may not always be clinically apparent, in which case patients are frequently referred for sonography. The purpose of this study was to document the sonographic features of head and neck lipomas. METHODS: Twenty-five patients with soft-tissue masses in the neck had sonography as their initial imaging study. A lipoma was suspected on the basis of findings at clinical examination in only eight of these patients. Lipoma was confirmed by fine-needle aspiration cytology in 11 patients, by excision biopsy in five patients, by CT in two patients, and by clinical examination with clinical sonographic follow-up (6 months to 2 years) in seven cases. RESULTS: Lipomas were well-defined (88%), compressible (100%), elliptical masses with the longest diameter parallel to the skin surface. All contained multiple echogenic lines parallel to the skin surface with no evidence of posterior enhancement or attenuation and no flow on color Doppler sonography. Compared with adjacent muscle, 76% of all lipomas were hyperechoic, 8% isoechoic, and 16% hypoechoic. CONCLUSION: The characteristic sonographic appearance of head and neck lipomas is that of an elliptical mass parallel to the skin surface that is hyperechoic relative to adjacent muscle and that contains linear echogenic lines at right angles to the ultrasound beam.

Adolescent↗
PubMed1998

Madelung disease: distribution of cervical fat and preoperative findings at sonography, MR, and CT.

PURPOSE: Our goal was to document the distribution of excess fat in the neck and to determine the preoperative role of sonography, CT, and MR imaging in patients with Madelung disease. METHODS: Eight patients with Madelung disease were examined preoperatively with sonography, CT, and MR imaging of the neck, and the extent to which each technique provided answers to the surgeons' questions--such as distribution of fat, course of the major vessels within the fat, and presence of tracheal compression and nonlipomatous lesions--was studied. RESULTS: Excess fat was seen predominantly in the posterior part of the neck (eight patients), under the trapezius (eight patients) and sternomastoid (six patients) muscles, in the supraclavicular fossa (five patients), between the paraspinal muscles (five patients), in the anterior part of the neck (suprahyoid in seven patients and infrahyoid in three patients), in the superior mediastinum (three patients), and in the prevertebral space (two patients). Excess fat deposition was also seen in the pretracheal space (one patient), extrapleural space (two patients), and over the cheeks (one patient), sites previously not described. CONCLUSION: As a preoperative investigative tool for Madelung disease, both MR imaging and noncontrast CT provide the surgeon with adequate information; sonography is less helpful.

Adipose Tissue↗
PubMed1998

Carcinoma showing thymiclike differentiation (CASTLE tumor).

A 67-year-old woman had had a neck mass for 10 years, which recently increased in size. Sonographic, CT, and MR examinations showed a mass in the carotid and posterior spaces (triangle) extending from below the submandibular gland to the supraclavicular fossa, displacing the common carotid artery and the sternomastoid anteriorly. The mass was solid, noncalcified with lobulated outlines, hypoechoic on sonograms, of soft-tissue density on CT scans, isointense on T1-weighted MR images, hyperintense on T2-weighted MR images, and enhanced mildly after injection of contrast material on CT and MR studies. Histologic examination revealed a carcinoma showing thymiclike differentiation, a rare tumor of the neck and thyroid gland.

Aged↗
PubMed1997

Hyperhomocyst(e)inemia is a risk factor for arterial endothelial dysfunction in humans.

BACKGROUND: Hyperhomocyst(e)inemia is associated with premature peripheral vascular, cerebrovascular, and coronary artery disease. Because homocysteine has been found to be damaging to endothelial cells in animal and cell culture studies, we evaluated the association between hyperhomocysteinemia and arterial endothelial dysfunction (a marker of early atherosclerosis) in asymptomatic adult subjects. METHODS AND RESULTS: Using high-resolution ultrasound, we measured endothelium-dependent flow-mediated dilation (EDD) and endothelium-independent nitroglycerin-induced dilation (GTN) of the brachial artery in 14 prospectively defined hyperhomocysteinemic (mean plasma homocysteine, 34.8+/-8.5 micromol/L), nonsmoking, healthy subjects aged 53+/-9 years and 14 control subjects with low plasma homocysteine levels (9.9+/-3.2 micromol/L). The two groups were well matched for age; sex; body mass index; blood pressure, blood cholesterol, folate, and vitamin B12 levels; and vessel diameter. EDD was significantly lower in hyperhomocysteinemic subjects (6.5+/-1.7%) than in subjects with low homocysteine levels (10.8+/-1.7%) (P<.001). GTN responses were similar in the two subject groups (P=.90). Multivariate analysis confirmed homocysteine level as the strongest predictor for impaired EDD, independent of age, sex, body mass index, or blood pressure, folate, vitamin B12, and cholesterol levels. CONCLUSIONS: Hyperhomocysteinemia is an independent risk factor for arterial endothelial dysfunction in healthy middle-aged adults.

Adult↗
PubMed1997

Retropharyngeal lymphadenopathy in nasopharyngeal carcinoma.

BACKGROUND: This study was done to investigate the size of normal retropharyngeal lymph nodes (RLN) and the incidence of retropharyngeal lymph node involvement in patients with nasopharyngeal carcinoma (NPC). METHODS: Forty-four NPC patients who had not yet received treatment and 20 control subjects underwent MRI scanning. The number and the maximum diameter of the short axis of the cervical lymph nodes were measured. The number of nasopharyngeal walls involved and the maximum diameter of the tumor were recorded. RESULTS: In 5 of 20 control subjects lateral RLN were identified; none of these nodes was greater than 2.5 mm. In the NPC patients, taking 4 mm as the upper limit of normal RLN, 89% of the patients had enlarged RLN. The number of nasopharyngeal walls involved and the maximum diameter of the primary tumor showed no statistical relationship with the involvement of RLN. There was a statistical association between RLN and level II node involvement, but not with other groups of neck nodes. CONCLUSION: Of all patients with NPC, 89% showed enlarged RLN. Its involvement was related to level II nodes but not to the number of nasopharyngeal sites involved nor with the maximum diameter of the tumor.

Adult↗
PubMed1997

Disappearing suprarenal masses in fetuses and infants.

This paper presents 12 infants (9 boys, 3 girls) in whom the diagnosis of a suprarenal mass (10 left, 2 bilateral) was made on antenatal sonography. All were otherwise healthy neonates who were born at term after a normal pregnancy, labor and delivery. The masses ranged from 1 to 3.5 cm in diameter on initial scans at gestational ages of 19-35 weeks. Eleven masses were hyperechoic and 4 of these contained small, well-defined cysts. The 12th was hypoechoic. Follow-up sonography showed complete disappearance of the mass antenatally in 1 case and postnatally by 4-6 months in 5 cases; there was marked diminution in the size of the mass by 2 months of age in 4 infants, by 4 months in 1 case and by 15 months in 1 case. Eleven were managed nonoperatively. Laparotomy (after disappearance of the mass) in the 12th case revealed only some fibrous tissue. The 11 echogenic masses resemble previously reported imaging findings in infants with histologically proven intra-abdominal sequestrated lung. Conservative management with careful sonographic follow-up should, therefore, be considered in otherwise healthy fetuses or neonates with these imaging findings. We are less certain what the hypoechoic mass represented.

Bronchopulmonary Sequestration↗
PubMed1997

Mammographic, sonographic and histopathological correlation of benign axillary masses.

Eight cases of benign isolated axillary masses due to tuberculous lymphadenitis (3), chronic inflammation (1), accessory axillary breast tissue (3) and lipoma (1) are presented. The mammographic, sonographic and histopathological features are described, differential diagnoses outlined and usefulness of mammography, ultrasound and ultrasound-guided tissue sampling discussed.

Adult↗
PubMed1997

Detectability and appearance of bile duct calculus on MR imaging of the abdomen using axial T1- and T2-weighted sequences.

This is a retrospective study with the objective of assessing the appearance and detectability of bile duct calculi on axial abdominal magnetic resonance imaging (MRI). Axial spin-echo (SE) T1-weighted and Turbo-spin-echo (TSE) T2-weighted images of the upper abdomen of 23 patients suffering from acute cholangitis with known bile duct calculi were retrospectively analysed. Bile duct calculi could be visualized on a T1-weighted SE sequence in 10 (47%) patients. T2-weighted TSE images identified bile duct calculi in 20 (87%) patients. On the T1-weighted sequence, eight out of 10 (80%) visualized common duct stones were slightly hyperintense compared to bile. On T2-weighted sequence, 27 out of 34 (79%) detectable common duct stones were uniformly hypointense compared to bile, but seven stones (21%) had mixed signal intensity.

Adolescent↗
PubMed1997

MRI and CT of metastatic hepatocellular carcinoma causing spinal cord compression.

We report the imaging features in five patients with metastatic hepatocellular carcinoma causing spinal cord compression, three of which were biopsy proven and two were in patients with known diagnosis of hepatocellular carcinoma. The radiographic, magnetic resonance imaging (MRI) and computed tomography (CT) features are highlighted. Although the occurrence of metastatic disease in hepatocellular carcinoma is exceedingly rare, it may be increasingly encountered as survival of patients is improved with advancing methods of therapy, both surgical and palliative. It often accompanies local recurrence, and invariably signals a grave prognosis with extremely short life expectancy. Unusually, two of the five patients in this series presented initially with skeletal metastases which led to the diagnosis of hepatocellular carcinoma.

Adult↗
PubMed1997

Safety of percutaneous biopsy of hepatocellular carcinoma with an 18 gauge automated needle.

OBJECTIVE: Accurate histological diagnosis and subtyping of hepatocellular carcinoma (hepatoma) is likely to be enhanced if a large biopsy tissue specimen is made available to the pathologist. However biopsy of this tumour can be dangerous, especially if the liver is cirrhotic and the lesion is superficial. This study evaluates the safety of an 18 gauge spring loaded side-cutting needle in the percutaneous biopsy of hepatoma in cirrhotic patients under ultrasonographic (US) guidance. Particular attention was paid to establishing the necessary length of needle track through interposing liver parenchyma to be certain of maximum safety. MATERIALS AND METHODS: One hundred and thirty-nine consecutive biopsy procedures were performed on 129 hepatomas which belonged to 113 men and 12 women of average age 57 +/- 15 years old (median 60, range 8 months-88 years). Ninety-six (69.1%) of these biopsies were performed in cirrhotic livers. The length of biopsy needle track traversing interposing liver parenchyma was less than 1 cm in two cases, 1 cm in 41 cases, between 1 and 2 cm in 46 cases and > 2 cm in 50 cases. The mean tumour size was 7.2 +/- 4.5 cm (median 6.8 cm, range 0.7-25 cm). The average number of needle pass in each biopsy was 2.1 +/- 0.8 times (median 2, range 1-5). RESULTS: One hundred and twenty-six (90.6%) of the biopsy procedures were diagnostic of hepatoma. There were two cases of post-biopsy bleeding, both occurred in procedures with an interposing liver parenchymal track less than 1 cm in length. CONCLUSION: The biopsy technique described was found to be safe for diagnosing hepatoma in patients with or without liver cirrhosis provided that the length of interposing liver parenchymal track is not < 1 cm.

Adolescent↗
PubMed1997

Pyogenic liver abscess: treatment with needle aspiration.

OBJECTIVE: Percutaneous needle aspiration as an alternative to continuous percutaneous catheter drainage in combination with systemic antibiotics for the treatment of pyogenic liver abscess has never been popular. The authors report their experience with needle aspiration and evaluate its safety, effectiveness and role in treating pyogenic liver abscess. MATERIALS AND METHODS: The results of needle aspiration performed in 101 liver abscesses of 64 unselected consecutive patients with male to female ratio of 2.5:1 and average age 56.3 +/- 16 years were reviewed. The abscesses were pyogenic in 63 patients (98.4%), and multiple in 18 patients (28.1%). Thirty-nine abscesses (38.6%) were > or = 5 cm in diameter. Complete pus removal from each abscess was attempted with 18 gauge thin-walled trocar needles and ultrasound guidance. RESULTS: The percentage of abscesses requiring one, two and three, or more sessions of aspiration was 49.5%, 23.7% and 26.7%, respectively. The overall success rate was 96.8%. The success rate was unrelated to the largest size or number of abscess in the patient. Two patients died from uncontrolled sepsis. One serious complication of liver laceration requiring laparotomy occurred. CONCLUSION: Percutaneous needle aspiration in combination with systemic antibiotics is safe and effective in treating pyogenic liver abscess, it should be considered as a first line alternative to catheter drainage, especially for multiple abscesses. The need for repeat aspirations follows a 'fifty per cent rule'.

Aged↗