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Biomedical subjects

J A Guthrie

Publications and source records attributed to J A Guthrie.

At least 19 recordsLinked to original sources
PubMed2001

Duplication of the vertebral artery: report of two cases and review of the literature.

Duplication of the vertebral artery is rare. We report two cases in which it was an incidental finding. In the first, duplication of the right vertebral artery was demonstrated by magnetic resonance angiography (MRA) and conventional angiography. The second patient had duplication of the right vertebral artery demonstrated by MRA. We discuss the origin of this abnormality, its radiological implications and its potential clinical significance are discussed.

Aged↗
PubMed2001

Non-operative management of the primary tumour in patients with incurable stage IV colorectal cancer.

BACKGROUND: Excision of primary colorectal cancer associated with irresectable synchronous metastases confers high morbidity and mortality with uncertain benefit. METHODS: For patients with incurable stage IV colorectal cancer, minimally symptomatic primary tumours were left in situ and 5-fluorouracil-based chemotherapy was administered systemically. Primary tumour-specific complications and survival were monitored. RESULTS: There were 13 men and 11 women with primary tumours in the right colon (eight), transverse colon (one), sigmoid colon (eight) or rectum (seven). Eleven patients had metastases limited to the liver (liver replacement less than 25 per cent in one, 25-50 per cent in four and more than 50 per cent in six) and 13 patients had extrahepatic disease (lung or peritoneum). Four patients with sigmoid colon tumours developed bowel obstruction, which required an uncomplicated operation in two and deployment of colonic stents in two patients, at 1, 3, 12 and 20 months from diagnosis. Three further patients underwent right hemicolectomy for abdominal pain of uncertain aetiology, with poor symptomatic relief, and another had a potentially curative operation following disease downstaging. The overall median survival was 10.3 months with a 1-year actuarial survival rate of 44 per cent. CONCLUSION: A policy to defer resection of minimally symptomatic primary colorectal cancer is associated with a low risk of complications before death from progressive systemic disease.

Abdominal Pain↗
PubMed2001

Dual phase helical CT versus portal venous phase CT for the detection of colorectal liver metastases: correlation with intra-operative sonography, surgical and pathological findings.

AIM: To assess whether dual phase helical computed tomography (DPCT) of the liver improves the detection of colorectal liver metastases compared with portal venous phase (PVP) imaging alone. MATERIALS AND METHODS: DPCT was performed in 33 consecutive patients before laparotomy for resection of colorectal liver metastases. CT comprised 8-mm slice collimation with a pitch of 1 to 1.25; imaging was commenced 20-25 and 65-70 s after the start of injection of 150 ml of contrast medium at 5 ml/s to coincide with hepatic arterial phase (HAP) and PVP contrast enhancement, respectively. Four blinded observers independently reviewed the HAP, PVP and DPCT images recording the site and size of all lesions. Alternative-free response receiver operating characteristic (AFROC) methodology was used to analyse the results, which were correlated with surgery, intra-operative ultrasound and histology. RESULTS: The mean observer sensitivities for malignant lesion detection were 75.3% for DPCT, 69.7% for PVP imaging and 66.7% for HAP imaging alone. There was a statistically significant improvement in malignant lesion detection using DPCT when compared with PVP imaging alone (P < 0.05). The mean areas under the AFROC curves were 0.84 for DPCT and 0.82 for PVP (P < 0.03) imaging alone. CONCLUSION: The detection of colorectal liver metastases was marginally better with DPCT than with PVP imaging alone, but the discovery of additional lesions did not affect the management of any of the patients in this study.

Aged↗
PubMed2001

Scleroderma "en coup de sabre": pathological evidence of intracerebral inflammation.

Linear scleroderma "en coup de sabre" (LScs) is associated with neurological complications, the pathogenesis of which is uncertain. A 27 year old woman is reported on who developed epilepsy and focal neurological signs in association with LScs. Brain MRI demonstrated predominantly ipsilateral relapsing and remitting grey and white matter lesions. Analysis of CSF and pathology obtained at brain biopsy provides evidence of an inflammatory process which may be amenable to immunosuppressive treatment.

Adult↗
PubMed2000

HIV and AIDS in aboriginal and Torres Strait Islander Australians: 1992-1998. The National HIV Surveillance Committee.

OBJECTIVE: To describe the epidemiological pattern of newly diagnosed HIV infection and AIDS among Indigenous Australians. DESIGN AND SETTING: National surveillance for newly diagnosed HIV infection and AIDS in Australia. Information on Indigenous status was sought at HIV/AIDS notification in all State/Territory health jurisdictions, except the Australian Capital Territory, and Victoria before June 1998. MAIN OUTCOME MEASURES: Number of people with newly diagnosed HIV per year and population rate of HIV diagnosis; demographic characteristics of people with HIV and AIDS diagnoses by Indigenous status. RESULTS: From 1992 to 1998, 127 Indigenous Australians were newly diagnosed with HIV infection and 55 were diagnosed with AIDS. The population rate of HIV diagnosis among Indigenous Australians (5.23/100,000 per year) was similar to that among non-Indigenous Australians (5.51/100,000 per year). The annual number of HIV diagnoses among Indigenous people was relatively stable, but among non-Indigenous people it declined steadily over time. A higher proportion of Indigenous people diagnosed with HIV were women (26.8% v 8.9%; P < 0.001). Although male homosexual contact was the predominant source of exposure for both Indigenous (46.7%) and non-Indigenous (75.0%) people with HIV infection, exposure by heterosexual contact (36.7% v 15.3%; P < 0.001) was reported more frequently among Indigenous people. CONCLUSION: Although HIV incidence was similar among Indigenous and non-Indigenous Australians, the lack of a recent decline in incidence and the higher proportion of Indigenous people exposed to HIV by heterosexual contact indicate the need to intensify interventions to prevent HIV transmission among Indigenous people.

Acquired Immunodeficiency Syndrome↗
PubMed2000

MRI of liver: a comparison of CNR enhancement using high dose and low dose ferumoxide infusion in patients with colorectal liver metastases.

The purpose of this study was to compare the effects of high dose (HD) and low dose (LD) ferumoxides infusions on lesion-to-liver contrast-to-noise ratio (CNR) using four different T(2)-weighted MR sequences. Seventy-three patients with known colorectal liver metastases underwent T(2)-weighted fast spin echo (FSE) imaging before and after ferumoxides. After ferumoxides, T(2)-weighted dual echo (DE) and T(2)-weighted GRE FLASH images were also obtained. To evaluate the relationship between TE length and lesion-to-liver CNR, the same FLASH sequence was repeated in 18 LD patients after lengthening the TE. Ferumoxides was administered at a dose of 15 micromol/kg (HD) and 7.5 micromol/kg (LD) in 45 and 28 patients, respectively. The effects of HD and LD ferumoxides infusions were measured as the percentage signal intensity change (PSIC) in the liver and lesions, lesion-to-liver CNR and the change in lesion-to-liver CNR (DeltaCNR). In both LD and HD groups, all CNR values obtained after SPIO were significantly greater than those observed with unenhanced FSE (p < 0.01). There was no significant difference between the mean CNR values obtained with either dose for any sequence. With the FLASH sequence, CNR increased progressively with longer TE. At the longest TE of 26 ms, mean CNR was higher than that recorded with any of the other sequences. Although mean liver PSIC was significantly greater in the HD group than in the LD group (p < 0.01) because the mean lesion PSIC was also greater in the HD group, the mean DeltaCNR after ferumoxides was not significantly different in the two groups. LD SPIO enhanced MR significantly increases lesion-to-liver CNR compared with unenhanced images. At 1. 0 T, HD and LD ferumoxides infusions produce comparable lesion-to-liver CNR. Our results suggest that at 1.0 T ferumoxides may be administered at a dose of 7.5 micromol/kg without loss of image quality.

Aged↗
PubMed2000

Hepatic lesion detection after superparamagnetic iron oxide enhancement: comparison of five T2-weighted sequences at 1.0 T by using alternative-free response receiver operating characteristic analysis.

PURPOSE: To compare the accuracy of five T2-weighted sequences in the detection of liver lesion at magnetic resonance (MR) imaging after superparamagnetic iron oxide (SPIO) enhancement. MATERIALS AND METHODS: Forty-nine candidates for hepatic resection with known coloretal metastases were examined. Before SPIO enhancement, fast spin-echo (SE) images were obtained. After enhancement, the same fast SE sequence and long; TR/short TE, short TE, long TR/TE, and T2-weighted fast low-angle shot (FLASH) sequences were used. All images were viewed independently by four observers who were blinded to the results of the other imaging sequences, the results of the other observers, and the findings at surgery and histopathologic examination. Four weeks after the initial reading, the combined long TR/short TE and long TR/TE dual-echo images were also viewed as an additional set. The alternative free response receiver operating characteristic (ROC) method was used to analyze the results, which were correlated with findings at surgery, intraoperative ultrasonography, and histopathologic examination. RESULTS: Irrespective of lesion size, the accuracy of all sequences after enhancement was significantly greater than that of the nonenhanced fast SE sequence (P < .01). Dual-echo and FLASH sequences were significantly more accurate than the enhanced fast SE sequence (P < .03 or P < .02, respectively). For all lesions, lesions smaller than 1 cm, and lesions 1 cm or larger, mean accuracies were as follows: dual-echo, 0.75, 0.54, and 0.93; FLASH, 0.75, 0.54, and 0.95; and enhanced fast SE, 0.72, 0.49, and 0.92. CONCLUSION: At 1.0 T, dual-echo and FLASH sequences are the most accurate pulse sequences after SPIO enhancement.

Aged↗
PubMed2000

Hepatocellular carcinoma in the cirrhotic liver: double-contrast MR imaging for diagnosis.

PURPOSE: To measure the sensitivity and accuracy of double-contrast magnetic resonance (MR) imaging for the diagnosis of hepatocellular carcinoma (HCC) in the cirrhotic liver. MATERIALS AND METHODS: Twenty-seven patients with MR features of dysplastic nodules and/or HCC were examined. T2-weighted spin-echo and T1-weighted gradient-echo imaging was performed before and after superparamagnetic iron oxide (SPIO) administration and immediately followed by T1-weighted gradient-echo imaging at 10, 40, and 120 seconds after bolus injection of a gadolinium-based contrast material. Nonenhanced, nonenhanced plus SPIO-enhanced, and nonenhanced plus SPIO-enhanced plus gadolinium-enhanced images were reviewed. Alternative-free response receiver operating characteristic (ROC) methodology was used to analyze the results, which were correlated with histopathologic findings after transplantation in 15 patients and at biopsy in 12. Lesions visualized with all three techniques were characterized as a dysplastic nodule or HCC, and ROC analysis was performed. RESULTS: For all observers, SPIO-enhanced MR imaging (mean accuracy, 0.76) was more accurate than nonenhanced MR imaging (mean accuracy, 0.64) (P <.04), and double-contrast MR imaging (mean accuracy, 0.86) was more accurate than SPIO-enhanced imaging (P <.05). Both types of lesions were correctly characterized with all three techniques, although observer confidence for lesion characterization was greatest with double-contrast MR imaging. CONCLUSION: Double-contrast MR imaging significantly improves the diagnosis of HCC compared with SPIO-enhanced and nonenhanced imaging (P <.01).

Adult↗
PubMed1999

Hepatic lesion detection: comparison of MR imaging after the administration of superparamagnetic iron oxide with dual-phase CT by using alternative-free response receiver operating characteristic analysis.

PURPOSE: To compare the performance of magnetic resonance (MR) imaging after the administration of superparamagnetic iron oxide (SPIO) and dual-phase computed tomography (CT) in the depiction of liver metastases. MATERIALS AND METHODS: Fifty-one hepatic resection candidates with known colorectal metastases were examined. MR imaging comprised fast spin-echo (SE) T2-weighted imaging, T1-weighted gradient-echo (GRE) fast low-angle shot imaging before SPIO enhancement, dual-echo SE imaging, T2-weighted fast low-angle shot imaging, and T1-weighted GRE imaging after SPIO enhancement. CT was performed with 8-mm collimation and 1:1 pitch; imaging commenced 20 seconds and 65-70 seconds after injection of 150 mL of contrast medium. All images were reviewed independently by four blinded observers. The alternative-free response receiver operating characteristic (ROC) method was used to analyze the results, which were correlated with findings from surgery, intraoperative ultrasonography, and histopathologic studies in 31 patients and with consensus review together with all other imaging and clinical follow-up in 20 patients. Sensitivities were also calculated. RESULTS: The mean sensitivity of MR was significantly higher than that of CT (p < .02): 79.8% for MR and 75.3% for CT for all lesions, and 80.6% for MR and 73.5% for CT for malignant lesions. The mean areas under the alternative-free response ROC curves were 0.83 for MR and 0.78 for CT (difference not significant). CONCLUSION: SPIO-enhanced MR imaging was more sensitive than dual-phase CT in the depiction of colorectal metastases.

Colorectal Neoplasms↗
PubMed1999

Dynamic contrast-enhanced MR imaging and dual-phase helical CT in the preoperative assessment of suspected pancreatic cancer: a comparative study with receiver operating characteristic analysis.

OBJECTIVE: The purpose of this study was to compare dynamic contrast-enhanced MR imaging and dual-phase helical CT in the preoperative assessment of patients with suspected pancreatic carcinoma. SUBJECTS AND METHODS: Thirty-three consecutive surgical candidates (20 men, 13 women; 39-81 years old) were included. MR imaging comprised fast spin-echo (TR/TE 4000/91), fat-suppressed T1-weighted spin-echo (500/15), and T1-weighted breath-hold gradient-echo fast low-angle shot (100/4; flip angle, 80 degrees) images before and after the administration of gadopentetate dimeglumine. Helical CT used 5-mm collimation with a pitch of 1:1.5-1.7; images were obtained 20 and 65-70 sec after injection of 150 ml of contrast material. Two pairs of interpreters who were unaware of the results of the other imaging method independently scored each examination for the presence of a lesion and for surgical resectability using a five-point scale. Results were correlated with surgery (n = 25) or consensus review (n = 8). Receiver operating characteristic methodology was used to analyze the results for resectability, and positive predictive values were calculated. RESULTS: Both MR imaging and helical CT revealed 29 of 31 lesions. In determining lesion resectability, the mean areas under the receiver operating characteristic curves were 0.96 and 0.81 (p = .01) and the positive predictive values were 86.5% and 76% (p = .02) for MR imaging and helical CT, respectively. CONCLUSION: MR imaging and helical CT performed equally well in lesion detection. MR imaging was significantly better in the assessment of resectability of pancreatic tumors.

Adenocarcinoma↗
PubMed1998

Assessment of resectability of pancreatic cancer with dynamic contrast-enhanced MR imaging: technique, surgical correlation and patient outcome.

The aim of our work was to investigate the use of a dynamic contrast-enhanced MR (DCEMR) technique for staging apparently localised pancreatic cancer, and to determine the patterns of tumour and vascular enhancement with this technique. Thirty-five consecutive patients were examined. The MR findings were correlated with surgical findings in 13 patients and with clinical outcome in 22 patients. Breath-hold gradient-echo fast low angle shot (TR = 100, TE = 4, flip angle 80 degrees ) acquisitions were obtained at 10 and 40 s (right anterior coronal oblique plane) and at 90 s (axial plane) following intravenous gadolinium. Mean contrast-to-noise ratio was higher on the first than the second acquisition (p < 0. 001) and higher on the second acquisition than the third (p < 0.005). Tumour conspicuity was greatest and arterial anatomy was best demonstrated on the first acquisition and the portal venous anatomy on the second. Small tumours were isointense by the third acquisition. Maximal intensity projections were helpful. The MR findings correctly predicted the surgical findings in 11 of 13 cases (85 %) and the clinical course in the other 22 patients. The DCEMR imaging technique is valuable in the staging of patients with pancreatic cancer. Capillary and portal venous phase images are both required for complete local staging.

Aged↗
PubMed1998

Effects of energy-matched pulsed and continuous ultrasound on tumor growth in mice.

BACKGROUND AND PURPOSE: A diagnosis of cancer is a contraindication for the use of therapeutic ultrasound (US). Continuous US applied to murine tumors has resulted in larger and heavier tumors compared with controls. We compared tumor growth using low-power continuous US and energy-matched pulsed US. SUBJECTS: Female C57BL/6 mice (N = 174) were used. METHODS: Animals received subcutaneous injections of methylcholanthrene tumor cells. The mice were randomly divided into three groups: 60 mice that received low-power continuous US for 5 minutes at 0.75 W/cm2 (LC US group), 63 mice that received pulsed US for 12.5 minutes at 1.5 W/cm2 (pulsed US group), and 51 mice that served as a control group. The LC and pulsed US groups received equal US energy. Both experimental groups received 10 treatments of 3-MHz US, which was applied directly over the tumor. The control group received identical handling but no US. After treatment, the tumors were excised, weighed, and measured. A one-way analysis of variance, followed by Newman-Keuls post hoc testing, was used to analyze the data. RESULTS: Mean tumor weights (in grams) and volumes (in cubic millimeters) were 0.563 g and 564 mm3 for the LC US group, 0.560 g and 525 mm3 for the pulsed US group, and 0.516 g and 406 mm3 for the control group. CONCLUSION AND DISCUSSION: Reducing total US energy will result in less growth of murine tumors. When infusing equal energy, continuous and pulsed US will produce similar effects on tumor growth.

Analysis of Variance↗
PubMed1998

Compared with parenteral nutrition, enteral feeding attenuates the acute phase response and improves disease severity in acute pancreatitis.

BACKGROUND: In patients with major trauma and burns, total enteral nutrition (TEN) significantly decreases the acute phase response and incidence of septic complications when compared with total parenteral nutrition (TPN). Poor outcome in acute pancreatitis is associated with a high incidence of systemic inflammatory response syndrome (SIRS) and sepsis. AIMS: To determine whether TEN can attenuate the acute phase response and improve clinical disease severity in patients with acute pancreatitis. METHODS: Glasgow score, Apache II, computed tomography (CT) scan score, C reactive protein (CRP), serum IgM antiendotoxin antibodies (EndoCAb), and total antioxidant capacity (TAC) were determined on admission in 34 patients with acute pancreatitis. Patients were stratified according to disease severity and randomised to receive either TPN or TEN for seven days and then re-evaluated. RESULTS: SIRS, sepsis, organ failure, and ITU stay, were globally improved in the enterally fed patients. The acute phase response and disease severity scores were significantly improved following enteral nutrition (CRP: 156 (117-222) to 84 (50-141), p < 0.005; APACHE II scores 8 (6-10) to 6 (4-8), p < 0.0001) without change in the CT scan scores. In parenterally fed patients these parameters did not change but there was an increase in EndoCAb antibody levels and a fall in TAC. Enterally fed patients showed no change in the level of EndoCAb antibodies and an increase in TAC. CONCLUSION: TEN moderates the acute phase response, and improves disease severity and clinical outcome despite unchanged pancreatic injury on CT scan. Reduced systemic exposure to endotoxin and reduced oxidant stress also occurred in the TEN group. Enteral feeding modulates the inflammatory and sepsis response in acute pancreatitis and is clinically beneficial.

APACHE↗
PubMed1997

Hepatic lesion detection at MR imaging: a comparative study with four sequences.

PURPOSE: To compare results with the following magnetic resonance (MR) imaging sequences in the detection of focal hepatic lesions: fast spin-echo (SE) before and after administration of superparamagnetic iron oxide (SPIO) particles, fat-suppressed T2-weighted SE, and dynamic gadolinium-enhanced fast low-angle shot (FLASH). MATERIALS AND METHODS: In 26 patients with known malignancy and documented focal liver lesions, 1.0-T MR imaging was performed prior to hepatic resection. All images were reviewed independently by four blinded observers. Sensitivity was calculated for each sequence and for each observer by means of alternative-free-response receiver operating characteristic (ROC) methods. RESULTS: The mean area under the alternative-free-response ROC curve with SPIO-enhanced fast SE (0.85) was significantly greater (P < .02) than that with all other sequences. Detection was significantly improved with SPIO-enhanced fast SE compared with dynamic gadolinium-enhanced FLASH (which was the best of the other three sequences) for all lesions (P < .002) and for malignant lesions (P < .0002). CONCLUSION: Findings with the SPIO-enhanced fast SE sequence improved detection of focal liver lesions and had the highest diagnostic accuracy.

Adipose Tissue↗
PubMed1996

Hilar cholangiocarcinomas: T2-weighted spin-echo and gadolinium-enhanced FLASH MR imaging.

PURPOSE: To investigate the use of magnetic resonance (MR) imaging with dynamic gadopentetate dimeglumine enhancement in hilar cholangiocarcinoma. MATERIALS AND METHODS: Twenty-four patients (14 men, 10 women; aged 27-78 years; mean age, 51 years) with hilar cholangiocarcinoma underwent T2-weighted spin-echo MR imaging in the axial plane and multisection, breath-hold, fast low-angle shot (FLASH) MR imaging in the coronal oblique plane before and at 30, 60, 90, and 120 seconds after bolus injection of gadopentetate dimeglumine. Morphologic features were recorded, and contrast medium enhancement characteristics and contrast-to-noise ratios were calculated for each sequence. RESULTS: All the lesions were hyperintense on T2-weighted spin-echo images and hypointense on FLASH images. On dynamic gadolinium-enhanced images, progressive heterogeneous enhancement was seen in all patients. Intrahepatic ductal dilatation was present in every patient. Intraluminal components were seen in 11 patients, lobar atrophy in 12, and segmental portal venous occlusion or stenosis in 13. Satellite lesions were present in four patients, and hilar lymph nodal enlargement in 11. Contrast-to-noise ratios were statistically significantly higher on T2-weighted spin-echo images than on all other images. CONCLUSION: Hilar cholangiocarcinomas have consistent enhancement and morphologic features that can be demonstrated with dynamic contrast-enhanced MR imaging.

Adult↗