Michael Sage - Academia.edu (original) (raw)

Papers by Michael Sage

Research paper thumbnail of Effect of intravenous contrast material on the integrity of the blood-brain barrier: experimental study

American Journal of Neuroradiology, 1984

Research paper thumbnail of Increased Permeability of the Blood-Brain Barrier after Carotid Renografin-76

American Journal of Neuroradiology, May 1, 1981

Increased permeability or " breakdown " of the bloodbrain barrier following the carotid injection... more Increased permeability or " breakdown " of the bloodbrain barrier following the carotid injection of various contrast media has been previously documented [1-6]. Trans ient ope ning of the blood-brain barrier may also be produc ed by injecting hyperosmotic mannitol or arabinose into th e interna l carotid artery [7-12]. CT scanning has recently b ee n a ppli ed to th e d efinition and quantitation of this barri e r breakdown [1 3 , 14]. This case report documents , with crani a l c omputed tomogra phy (CT) , disruption of the bloodbra in b arri e r after th e intracarotid injection of a hyperos motic iodinated contrast media. Case Report A 43-yea r-old woman was admitted for reevaluation of poorly co ntrolled hypertension and renal artery sten osis. Whil e in th e hospital she had th e acute onset of left hemiparesis and sensory loss with co mplete resolution within 4 hours. Sh e report ed several similar epi sodes over th e preceding few month s. Arc h aortog raph y using Renog rafin-76 (two injection s of 60 ml eac h) defin ed a narrowin g at th e ori gin of th e right internal ca rotid artery. To obtain better visuali zati on of thi s abnormality, th e angiographer chose to exc hange cath eters for selective cath eterizati on of th e ri ght comm on ca rotid artery. By acc ident , 10 ml of Renog rafin-76 (rath er th an Renografin-60) were injec ted at a rate of 7 ml / sec. Abou t 10 min after injecti on and aft er th e cath eter had been removed from th e carotid artery, th e pati ent devel oped a left body foca l motor seizu re with secondary generalization lasting for about 2 min. Her bl ood pressure was stabl e and no seizure medicati on was administered. Neurolog ic examinati on about 15 min later revea led onl y a mild lett ce ntral fac ial wea kn ess th at had disappeared by 3 hr later. CT was perform ed about 40 min aft er th e intracarotid injecti on of Renog rafin-76. No intravenous contrast medium was injected. Pro minent enh ance ment of th e gray matter was demonstrated in th e ri ght brain in the di stributi on of th e anteri or and middl e ce rebral arteries (fi g. 1). Th ere was no enhance ment in th e distributi on of th e rig ht posteri or ce rebral artery or th e left brain vasc ulature, which had not been injected with contrast materi al. Diffu se decreased att enuation consistent with generalized vasogenic edema was evident throughout th e white matt er of th e ri ght hemi sph ere.

Research paper thumbnail of Muscular and CNS effects of carotid artery administration of contrast media in rabbits

American Journal of Neuroradiology, 1990

Research paper thumbnail of The effect of contrast medium viscosity on the blood-brain barrier after intracarotid injection in the rabbit

American Journal of Neuroradiology, 1989

Research paper thumbnail of The effect of intracarotid nonionic contrast media on the blood-brain barrier in acute hypertension

American Journal of Neuroradiology, 1994

To determine whether acute hypertension (HT) is a risk factor for damage to th e blood-brain barr... more To determine whether acute hypertension (HT) is a risk factor for damage to th e blood-brain barrier in carotid angiography with nonionic contrast media. METHODS: Anesthetized rats received intravenous injections of technetium-99m-pertechnetate and horseradish peroxidase. Two groups of rats received metaraminol to raise their blood pressure to between 165 and 190 mmHg peak systolic and then received intracarotid injections of saline or iopamidol. Two other groups remained normotensive and received intracarotid injections of saline or iopamidol. Animals were perfused with a fixative solution and their brains removed. Activity of extravasated T c-99mpertechnetate was determined to assess blood-brain barrier breakdown. Brains were then sectioned, treated histochemically to visualize extravasated horseradish peroxidase, and ranked vi sually according to horseradish peroxidase staining. RESULTS: Extravasation of both tracers was significantly greater in the hypertensive group that received contrast media tha n in the other three groups. CONCLUSIONS: Acute hypertension potentiates the blood-brain barrier-damaging effects of nonionic contrast media during carotid angiography in rats. Index terms: Hypertension ; Blood-brain barrier; Angiography , contrast media; Angiograph y ; Brain , effects of drugs on; Animal studies; Arteries, carotid

Research paper thumbnail of A comparison of blood-brain barrier disruption by intracarotid iohexol and iodixanol in the rabbit

American Journal of Neuroradiology, Sep 1, 1987

Research paper thumbnail of The blood-brain barrier: an important concept in neuroimaging

American Journal of Neuroradiology, Apr 1, 1994

Research paper thumbnail of Comparison of blood-brain barrier disruption by intracarotid iopamidol and methylglucamine iothalamate

American Journal of Neuroradiology, Jul 1, 1983

Research paper thumbnail of Intramedullary penetrance of metrizamide in the dog spinal cord

American Journal of Neuroradiology, Jul 1, 1981

Research paper thumbnail of Brain parenchyma penetration by intrathecal nonionic iopamidol

AJNR. American journal of neuroradiology

Iopamidol, a nonionic, water-soluble contrast medium, has been recently recommended for myelograp... more Iopamidol, a nonionic, water-soluble contrast medium, has been recently recommended for myelography. As with other such media, the extent of parenchymal penetration is of interest in relation to the genesis of clinical complications. In this study the degree and depth of brain penetration of intrathecal iopamidol, using an iodine concentration of 280 mg l/ml, were compared at 15 and 60 min in adult greyhound dogs using coronal computed tomographic scanning of the brain after removal. A significant but patchy penetration corresponding to the cortical sulci was demonstrated at 15 min, while by 60 min there had been a further increase in the distribution and concentration of the contrast medium. Comparing the present study with a previous series using metrizamide and methylglucamine iothalamate at a similar iodine concentration (280 mg l/ml), no significant difference in the depth or degree of penetration at 60 min was found between the three contrast media, indicating a similar rate o...

Research paper thumbnail of Brain parenchyma penetration by intrathecal ionic and nonionic contrast media

AJNR. American journal of neuroradiology

Metrizamide, a nonionic water-soluble contrast medium, has been shown to penetrate normal brain w... more Metrizamide, a nonionic water-soluble contrast medium, has been shown to penetrate normal brain when injected intrathecally. Recently it was suggested that the complications following intrathecal metrizamide are directly related to the cerebral concentration reached. Metrizamide, both in experimental animals and clinically, is regarded as less neurotoxic than equivalent iodine concentrations of ionic contrast media. In this study the degree and depth of brain penetration of intrathecal metrizamide and methylglucamine iothalamate (Conray 280), using a similar iodine concentration (280 mg l/ml), was compared at 1 hr in adult greyhound dogs. The depth of penetration and concentration reached in the cortical gray matter was determined by coronal computed tomographic scanning of the brain after removal. No significant difference was found between the two contrast media, suggesting that the rate of diffusion across the cerebrospinal fluid-brain interface is similar and that the difference...

Research paper thumbnail of Traumatic avulsion fracture of the occipital condyles and clivus and associated unilateral atlantooccipital distraction

American Journal of Neuroradiology, 1990

Research paper thumbnail of The inter-sonographer reliability of carotid duplex ultrasound

Australasian Radiology, 2001

Stroke is the third most common cause of death in Australia. 1 The risk of stroke associated with... more Stroke is the third most common cause of death in Australia. 1 The risk of stroke associated with carotid artery disease is high and relates to the degree of narrowing of the internal carotid artery (ICA). 2 Current techniques for the assessment of carotid artery disease include digital subtraction angiography (DSA), computed tomography angiography (CTA), magnetic resonance angiography (MRA) and carotid duplex ultrasound (CDUS). 3 CDUS is considered to be safe, relatively inexpensive and repeatable. It is also reported to be an operator dependant tool of investigation with varying levels of accuracy between different sites. 4-6 Carotid duplex ultrasound is based on the combination of high resolution B mode imaging and spectral Doppler. Variations in blood flow velocity within an artery can be used to estimate the degree of stenosis caused by the presence of plaque within the vessel. 7 These estimates require the measurement of one or a combination of the following parameters: peak systolic velocity (PSV), end diastolic velocity (EDV) at the point of maximum stenosis or the peak systolic velocity ratio (PSVR, peak velocity at the point of maximum stenosis in the ICA divided by PSV in the unobstructed common carotid artery (CCA) 1 cm or more below bifurcation). 7,8 In 1991, the results of the North American Symptomatic Carotid Endarterectomy Trial (NASCET) 2 were published. These results demonstrated a significant reduction in the number of strokes after carotid endarterectomy (CEA) compared with the best medical treatment in symptomatic patients with high grade (>70%) stenosis. Since then, numerous studies have compared CDUS measurements of ICA stenosis to DSA

Research paper thumbnail of Medical Registration and Recognition as a Specialist in Radiology in Australia

Investigative Radiology, 1994

Research paper thumbnail of Resource-Based Relative Value Scale for Organ Imaging Services

Investigative Radiology, 1991

MICHAEL, ROBIN BSc (Hons), GradDipCompSc, MPH (FMC); SAGE, MICHAEL MD, FRACR, FRCP, FRCR (FMC); H... more MICHAEL, ROBIN BSc (Hons), GradDipCompSc, MPH (FMC); SAGE, MICHAEL MD, FRACR, FRCP, FRCR (FMC); HEWITT, BRENDAN BA (FMC), KYM PIPER (FMC); SZEP, PETER AssDipRadTech, AssDipBusAdmin, ACHA (FMC); GANLEY, ELIZABETH DipT ( ...

Research paper thumbnail of The In Vitro Activation of Complement by Radiologic Contrast Materials and its Inhibition with ??-Aminocaproic Acid

Investigative Radiology, 1981

Radiologic contrast materials activate complement by both the classical and alternative pathways.... more Radiologic contrast materials activate complement by both the classical and alternative pathways. This activation is time, dose, and temperature dependent and is able to proceed with equal facility in either the presence or absence of Ca++ or Mg++ chelating reagents (EGTA, EDTA). All the components examined (C1, C4, C2, Factor B, C3, and C5) were consumed during complement activation. Immune complexes are produced during interaction of serum with contrast materials. The activation of complement by contrast materials appears to be principally initiated by the activation of plasminogen to plasmin. Inhibition of plasminogen activators by epsilon-aminocaproic acid affects complement activation markedly.

Research paper thumbnail of Evaluating the clinical efficacy of diagnostic imaging procedures

European Journal of Radiology, 1992

Research paper thumbnail of Endosonographic Imaging of Anal Sphincter Injury

Diseases of the Colon & Rectum, 2003

This study was designed to test the hypothesis that the extent of anal sphincter muscle injury as... more This study was designed to test the hypothesis that the extent of anal sphincter muscle injury as graded at endosonography correlates with the degree of functional impairment. Three hundred and thirty adults presenting for evaluation of fecal incontinence were recruited. Ultrasound was performed with a 7.5-MHz radial rotating axial endoprobe in the left lateral position. Anal sphincter muscle tears were graded on the basis of the degree of circumferential involvement (< or >25 percent) and by an assessment of the superoinferior longitudinal extent of an external anal sphincter tear. Muscles that demonstrated multiple tears, poor visualization, or fragmentation were classed as fragmented. Sphincter injuries were correlated with basal and squeeze pressures at manometry, pudendal nerve terminal latencies, and the severity of symptoms using the Parks-Browning clinical score. Patients with an intact external anal sphincter had a higher squeeze pressure (mean, 162.6 cm H(2)O) than those with a partial- (mean, 125.7 cm H(2)O) or full-length tear (mean, 124.9 cm H(2)O; P < 0.0001). There was no significant difference in squeeze pressure between those with partial- vs. full-length external anal sphincter tears nor between circumference tears < or >25 percent. Basal pressure was significantly lower in those with a full-length external anal sphincter tear (47.8 cm H(2)O) vs. an intact external anal sphincter (65.7 cm H(2)O; P < 0.001). The basal pressure in those with an intact internal anal sphincter was not significantly different from those with clearly defined internal anal sphincter tears, and the degree of circumferential involvement was also not important in this regard. However, those with a fragmented internal anal sphincter had a significantly lower basal pressure than other subgroups of internal anal sphincter injuries (P < 0.001). There was no association between external or internal anal sphincter status and the mean pudendal nerve terminal motor latency, suggesting the patient groups were neurologically similar. There was no significant association between external or internal anal sphincter status and the severity of reported symptoms. Correlations between the presence or absence of muscle tears and reduced manometric function have been identified. Further grading of tears was of less importance. No relationship between muscle injuries and the severity of clinical symptoms could be elicited.

Research paper thumbnail of Anal sphincter tears in patients with rectal prolapse and faecal incontinence

Colorectal Disease, 2003

Objective Faecal incontinence often persists after surgery for rectal prolapse. Multiple mechanis... more Objective Faecal incontinence often persists after surgery for rectal prolapse. Multiple mechanisms have been proposed as responsible, however, anal sphincter integrity has only been studied in a handful of cases. This study assesses the incidence of ultrasound detected anal sphincter tears in patients with rectal prolapse and faecal incontinence. Methods Retrospective search of medical records at Flinders Medical Centre over a 7-year period to identify patients with full thickness rectal prolapse and faecal incontinence who had undergone endosonographical imaging of the anal sphincter complex. Anal manometry and pudendal nerve terminal motor latency studies were also included. Results Twenty-one patients were identified (1 male, 20 female) of median age 67.5 years. Fifteen (71%) subjects had an abnormality in the anal sphincter complex on endoanal ultrasound. Of these, the defects in 4 (19%) patients were isolated to the internal sphincter, 3 (14%) to the external sphincter and in the remaining 8 (38%) subjects, defects were found in both internal and external sphincters. The degree of sphincteric defect was variable but at least 6 (29%) of the study group had full-length external sphincter tears. In the 19 patients studied, anal manometry revealed reduced basal and squeeze pressures in the majority. Delayed pudendal nerve terminal motor latency was evident in 9 of 18 patients studied. Conclusion Anal sphincter tears are common in patients presenting with rectal prolapse and faecal incontinence. The faecal incontinence associated with prolapse appears to be multifactorial in aetiology. Anal sphincter defects are likely to contribute to persistent faecal incontinence or recurrence following rectal prolapse. Endoanal ultrasound derived knowledge of anal sphincter injury may guide surgical management in problematic cases.

Research paper thumbnail of CT of intracerebral haemorrhage due to mycotic aneurysms�Case report

Neuroradiology, 1980

The CT findings in a case of intracerebral haematoma due to rupture of a mycotic aneurysm are pre... more The CT findings in a case of intracerebral haematoma due to rupture of a mycotic aneurysm are presented. In addition to the haematoma, CT demonstrated small focal areas of cortical enhancement, which corresponded to the peripheral aneurysms seen on angiography. Such findings are thought to be characteristic; a brief differential diagnosis is discussed.

Research paper thumbnail of Effect of intravenous contrast material on the integrity of the blood-brain barrier: experimental study

American Journal of Neuroradiology, 1984

Research paper thumbnail of Increased Permeability of the Blood-Brain Barrier after Carotid Renografin-76

American Journal of Neuroradiology, May 1, 1981

Increased permeability or " breakdown " of the bloodbrain barrier following the carotid injection... more Increased permeability or " breakdown " of the bloodbrain barrier following the carotid injection of various contrast media has been previously documented [1-6]. Trans ient ope ning of the blood-brain barrier may also be produc ed by injecting hyperosmotic mannitol or arabinose into th e interna l carotid artery [7-12]. CT scanning has recently b ee n a ppli ed to th e d efinition and quantitation of this barri e r breakdown [1 3 , 14]. This case report documents , with crani a l c omputed tomogra phy (CT) , disruption of the bloodbra in b arri e r after th e intracarotid injection of a hyperos motic iodinated contrast media. Case Report A 43-yea r-old woman was admitted for reevaluation of poorly co ntrolled hypertension and renal artery sten osis. Whil e in th e hospital she had th e acute onset of left hemiparesis and sensory loss with co mplete resolution within 4 hours. Sh e report ed several similar epi sodes over th e preceding few month s. Arc h aortog raph y using Renog rafin-76 (two injection s of 60 ml eac h) defin ed a narrowin g at th e ori gin of th e right internal ca rotid artery. To obtain better visuali zati on of thi s abnormality, th e angiographer chose to exc hange cath eters for selective cath eterizati on of th e ri ght comm on ca rotid artery. By acc ident , 10 ml of Renog rafin-76 (rath er th an Renografin-60) were injec ted at a rate of 7 ml / sec. Abou t 10 min after injecti on and aft er th e cath eter had been removed from th e carotid artery, th e pati ent devel oped a left body foca l motor seizu re with secondary generalization lasting for about 2 min. Her bl ood pressure was stabl e and no seizure medicati on was administered. Neurolog ic examinati on about 15 min later revea led onl y a mild lett ce ntral fac ial wea kn ess th at had disappeared by 3 hr later. CT was perform ed about 40 min aft er th e intracarotid injecti on of Renog rafin-76. No intravenous contrast medium was injected. Pro minent enh ance ment of th e gray matter was demonstrated in th e ri ght brain in the di stributi on of th e anteri or and middl e ce rebral arteries (fi g. 1). Th ere was no enhance ment in th e distributi on of th e rig ht posteri or ce rebral artery or th e left brain vasc ulature, which had not been injected with contrast materi al. Diffu se decreased att enuation consistent with generalized vasogenic edema was evident throughout th e white matt er of th e ri ght hemi sph ere.

Research paper thumbnail of Muscular and CNS effects of carotid artery administration of contrast media in rabbits

American Journal of Neuroradiology, 1990

Research paper thumbnail of The effect of contrast medium viscosity on the blood-brain barrier after intracarotid injection in the rabbit

American Journal of Neuroradiology, 1989

Research paper thumbnail of The effect of intracarotid nonionic contrast media on the blood-brain barrier in acute hypertension

American Journal of Neuroradiology, 1994

To determine whether acute hypertension (HT) is a risk factor for damage to th e blood-brain barr... more To determine whether acute hypertension (HT) is a risk factor for damage to th e blood-brain barrier in carotid angiography with nonionic contrast media. METHODS: Anesthetized rats received intravenous injections of technetium-99m-pertechnetate and horseradish peroxidase. Two groups of rats received metaraminol to raise their blood pressure to between 165 and 190 mmHg peak systolic and then received intracarotid injections of saline or iopamidol. Two other groups remained normotensive and received intracarotid injections of saline or iopamidol. Animals were perfused with a fixative solution and their brains removed. Activity of extravasated T c-99mpertechnetate was determined to assess blood-brain barrier breakdown. Brains were then sectioned, treated histochemically to visualize extravasated horseradish peroxidase, and ranked vi sually according to horseradish peroxidase staining. RESULTS: Extravasation of both tracers was significantly greater in the hypertensive group that received contrast media tha n in the other three groups. CONCLUSIONS: Acute hypertension potentiates the blood-brain barrier-damaging effects of nonionic contrast media during carotid angiography in rats. Index terms: Hypertension ; Blood-brain barrier; Angiography , contrast media; Angiograph y ; Brain , effects of drugs on; Animal studies; Arteries, carotid

Research paper thumbnail of A comparison of blood-brain barrier disruption by intracarotid iohexol and iodixanol in the rabbit

American Journal of Neuroradiology, Sep 1, 1987

Research paper thumbnail of The blood-brain barrier: an important concept in neuroimaging

American Journal of Neuroradiology, Apr 1, 1994

Research paper thumbnail of Comparison of blood-brain barrier disruption by intracarotid iopamidol and methylglucamine iothalamate

American Journal of Neuroradiology, Jul 1, 1983

Research paper thumbnail of Intramedullary penetrance of metrizamide in the dog spinal cord

American Journal of Neuroradiology, Jul 1, 1981

Research paper thumbnail of Brain parenchyma penetration by intrathecal nonionic iopamidol

AJNR. American journal of neuroradiology

Iopamidol, a nonionic, water-soluble contrast medium, has been recently recommended for myelograp... more Iopamidol, a nonionic, water-soluble contrast medium, has been recently recommended for myelography. As with other such media, the extent of parenchymal penetration is of interest in relation to the genesis of clinical complications. In this study the degree and depth of brain penetration of intrathecal iopamidol, using an iodine concentration of 280 mg l/ml, were compared at 15 and 60 min in adult greyhound dogs using coronal computed tomographic scanning of the brain after removal. A significant but patchy penetration corresponding to the cortical sulci was demonstrated at 15 min, while by 60 min there had been a further increase in the distribution and concentration of the contrast medium. Comparing the present study with a previous series using metrizamide and methylglucamine iothalamate at a similar iodine concentration (280 mg l/ml), no significant difference in the depth or degree of penetration at 60 min was found between the three contrast media, indicating a similar rate o...

Research paper thumbnail of Brain parenchyma penetration by intrathecal ionic and nonionic contrast media

AJNR. American journal of neuroradiology

Metrizamide, a nonionic water-soluble contrast medium, has been shown to penetrate normal brain w... more Metrizamide, a nonionic water-soluble contrast medium, has been shown to penetrate normal brain when injected intrathecally. Recently it was suggested that the complications following intrathecal metrizamide are directly related to the cerebral concentration reached. Metrizamide, both in experimental animals and clinically, is regarded as less neurotoxic than equivalent iodine concentrations of ionic contrast media. In this study the degree and depth of brain penetration of intrathecal metrizamide and methylglucamine iothalamate (Conray 280), using a similar iodine concentration (280 mg l/ml), was compared at 1 hr in adult greyhound dogs. The depth of penetration and concentration reached in the cortical gray matter was determined by coronal computed tomographic scanning of the brain after removal. No significant difference was found between the two contrast media, suggesting that the rate of diffusion across the cerebrospinal fluid-brain interface is similar and that the difference...

Research paper thumbnail of Traumatic avulsion fracture of the occipital condyles and clivus and associated unilateral atlantooccipital distraction

American Journal of Neuroradiology, 1990

Research paper thumbnail of The inter-sonographer reliability of carotid duplex ultrasound

Australasian Radiology, 2001

Stroke is the third most common cause of death in Australia. 1 The risk of stroke associated with... more Stroke is the third most common cause of death in Australia. 1 The risk of stroke associated with carotid artery disease is high and relates to the degree of narrowing of the internal carotid artery (ICA). 2 Current techniques for the assessment of carotid artery disease include digital subtraction angiography (DSA), computed tomography angiography (CTA), magnetic resonance angiography (MRA) and carotid duplex ultrasound (CDUS). 3 CDUS is considered to be safe, relatively inexpensive and repeatable. It is also reported to be an operator dependant tool of investigation with varying levels of accuracy between different sites. 4-6 Carotid duplex ultrasound is based on the combination of high resolution B mode imaging and spectral Doppler. Variations in blood flow velocity within an artery can be used to estimate the degree of stenosis caused by the presence of plaque within the vessel. 7 These estimates require the measurement of one or a combination of the following parameters: peak systolic velocity (PSV), end diastolic velocity (EDV) at the point of maximum stenosis or the peak systolic velocity ratio (PSVR, peak velocity at the point of maximum stenosis in the ICA divided by PSV in the unobstructed common carotid artery (CCA) 1 cm or more below bifurcation). 7,8 In 1991, the results of the North American Symptomatic Carotid Endarterectomy Trial (NASCET) 2 were published. These results demonstrated a significant reduction in the number of strokes after carotid endarterectomy (CEA) compared with the best medical treatment in symptomatic patients with high grade (>70%) stenosis. Since then, numerous studies have compared CDUS measurements of ICA stenosis to DSA

Research paper thumbnail of Medical Registration and Recognition as a Specialist in Radiology in Australia

Investigative Radiology, 1994

Research paper thumbnail of Resource-Based Relative Value Scale for Organ Imaging Services

Investigative Radiology, 1991

MICHAEL, ROBIN BSc (Hons), GradDipCompSc, MPH (FMC); SAGE, MICHAEL MD, FRACR, FRCP, FRCR (FMC); H... more MICHAEL, ROBIN BSc (Hons), GradDipCompSc, MPH (FMC); SAGE, MICHAEL MD, FRACR, FRCP, FRCR (FMC); HEWITT, BRENDAN BA (FMC), KYM PIPER (FMC); SZEP, PETER AssDipRadTech, AssDipBusAdmin, ACHA (FMC); GANLEY, ELIZABETH DipT ( ...

Research paper thumbnail of The In Vitro Activation of Complement by Radiologic Contrast Materials and its Inhibition with ??-Aminocaproic Acid

Investigative Radiology, 1981

Radiologic contrast materials activate complement by both the classical and alternative pathways.... more Radiologic contrast materials activate complement by both the classical and alternative pathways. This activation is time, dose, and temperature dependent and is able to proceed with equal facility in either the presence or absence of Ca++ or Mg++ chelating reagents (EGTA, EDTA). All the components examined (C1, C4, C2, Factor B, C3, and C5) were consumed during complement activation. Immune complexes are produced during interaction of serum with contrast materials. The activation of complement by contrast materials appears to be principally initiated by the activation of plasminogen to plasmin. Inhibition of plasminogen activators by epsilon-aminocaproic acid affects complement activation markedly.

Research paper thumbnail of Evaluating the clinical efficacy of diagnostic imaging procedures

European Journal of Radiology, 1992

Research paper thumbnail of Endosonographic Imaging of Anal Sphincter Injury

Diseases of the Colon & Rectum, 2003

This study was designed to test the hypothesis that the extent of anal sphincter muscle injury as... more This study was designed to test the hypothesis that the extent of anal sphincter muscle injury as graded at endosonography correlates with the degree of functional impairment. Three hundred and thirty adults presenting for evaluation of fecal incontinence were recruited. Ultrasound was performed with a 7.5-MHz radial rotating axial endoprobe in the left lateral position. Anal sphincter muscle tears were graded on the basis of the degree of circumferential involvement (< or >25 percent) and by an assessment of the superoinferior longitudinal extent of an external anal sphincter tear. Muscles that demonstrated multiple tears, poor visualization, or fragmentation were classed as fragmented. Sphincter injuries were correlated with basal and squeeze pressures at manometry, pudendal nerve terminal latencies, and the severity of symptoms using the Parks-Browning clinical score. Patients with an intact external anal sphincter had a higher squeeze pressure (mean, 162.6 cm H(2)O) than those with a partial- (mean, 125.7 cm H(2)O) or full-length tear (mean, 124.9 cm H(2)O; P < 0.0001). There was no significant difference in squeeze pressure between those with partial- vs. full-length external anal sphincter tears nor between circumference tears < or >25 percent. Basal pressure was significantly lower in those with a full-length external anal sphincter tear (47.8 cm H(2)O) vs. an intact external anal sphincter (65.7 cm H(2)O; P < 0.001). The basal pressure in those with an intact internal anal sphincter was not significantly different from those with clearly defined internal anal sphincter tears, and the degree of circumferential involvement was also not important in this regard. However, those with a fragmented internal anal sphincter had a significantly lower basal pressure than other subgroups of internal anal sphincter injuries (P < 0.001). There was no association between external or internal anal sphincter status and the mean pudendal nerve terminal motor latency, suggesting the patient groups were neurologically similar. There was no significant association between external or internal anal sphincter status and the severity of reported symptoms. Correlations between the presence or absence of muscle tears and reduced manometric function have been identified. Further grading of tears was of less importance. No relationship between muscle injuries and the severity of clinical symptoms could be elicited.

Research paper thumbnail of Anal sphincter tears in patients with rectal prolapse and faecal incontinence

Colorectal Disease, 2003

Objective Faecal incontinence often persists after surgery for rectal prolapse. Multiple mechanis... more Objective Faecal incontinence often persists after surgery for rectal prolapse. Multiple mechanisms have been proposed as responsible, however, anal sphincter integrity has only been studied in a handful of cases. This study assesses the incidence of ultrasound detected anal sphincter tears in patients with rectal prolapse and faecal incontinence. Methods Retrospective search of medical records at Flinders Medical Centre over a 7-year period to identify patients with full thickness rectal prolapse and faecal incontinence who had undergone endosonographical imaging of the anal sphincter complex. Anal manometry and pudendal nerve terminal motor latency studies were also included. Results Twenty-one patients were identified (1 male, 20 female) of median age 67.5 years. Fifteen (71%) subjects had an abnormality in the anal sphincter complex on endoanal ultrasound. Of these, the defects in 4 (19%) patients were isolated to the internal sphincter, 3 (14%) to the external sphincter and in the remaining 8 (38%) subjects, defects were found in both internal and external sphincters. The degree of sphincteric defect was variable but at least 6 (29%) of the study group had full-length external sphincter tears. In the 19 patients studied, anal manometry revealed reduced basal and squeeze pressures in the majority. Delayed pudendal nerve terminal motor latency was evident in 9 of 18 patients studied. Conclusion Anal sphincter tears are common in patients presenting with rectal prolapse and faecal incontinence. The faecal incontinence associated with prolapse appears to be multifactorial in aetiology. Anal sphincter defects are likely to contribute to persistent faecal incontinence or recurrence following rectal prolapse. Endoanal ultrasound derived knowledge of anal sphincter injury may guide surgical management in problematic cases.

Research paper thumbnail of CT of intracerebral haemorrhage due to mycotic aneurysms�Case report

Neuroradiology, 1980

The CT findings in a case of intracerebral haematoma due to rupture of a mycotic aneurysm are pre... more The CT findings in a case of intracerebral haematoma due to rupture of a mycotic aneurysm are presented. In addition to the haematoma, CT demonstrated small focal areas of cortical enhancement, which corresponded to the peripheral aneurysms seen on angiography. Such findings are thought to be characteristic; a brief differential diagnosis is discussed.