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Biomedical subjects

C H Nordström

Publications and source records attributed to C H Nordström.

At least 19 recordsLinked to original sources
PubMed2005

The Lund concept: is this logical?

The optimal therapy of sustained increase in intracranial pressure (ICP) is still controversial. The "Lund concept" is based on the physiological volume regulation of the intracranial compartments. In addition to its other functions the blood-brain barrier (BBB) is the most important regulator of brain volume. Water exchange across the intact BBB is counteracted by the low permeability to crystalloids (mainly Na+ and Cl-) combined with the high osmotic pressure (5,700 mmHg) on both sides of the BBB. If the BBB is disrupted transcapillary water transport will be determined by the differences in hydrostatic and colloid osmotic pressure between the intra- and extracapillary compartments. Under pathological conditions pressure autoregulation of cerebral blood flow is often impaired and intracapillary hydrostatic pressure will depend on variations in systemic blood pressure. The "Lund concept" can be summarized in four paragraphs: I. Reduction of stress response and cerebral energy metabolism; II. Reduction of capillary hydrostatic pressure; III. Maintenance of colloid osmotic pressure and control of fluid balance; IV. Reduction of cerebral blood volume. The efficacy of the treatment protocol has been evaluated in experimental and clinical studies regarding the physiological and biochemical (utilizing intracerebral microdialysis) effects. The clinical experiences have been favourable.

Animals↗
PubMed2004

Adverse biochemical and physiological effects of prostacyclin in experimental brain oedema.

BACKGROUND: Prostacyclin (PGI2) and its stable analogues are known to reduce capillary hydraulic permeability. This study explores the biochemical and physiological effects of i.v. infusion of low-dose PGI2 in an experimental model of vasogenic brain oedema. METHODS: Twenty-seven anaesthetized and mechanically ventilated piglets with brain oedema induced by intrathecal injection of lipopolysaccharide (LPS) were used. Five of the animals received a continuous infusion of PGI2 (1 ng kg(-1) min(-1)) i.v. Four microdialysis catheters were placed in the brain to measure interstitial concentrations of glucose, lactate, and glycerol. Mean arterial pressure (MAP), intracranial pressure (ICP) and temperature were monitored continuously. Low-dose infusion of PGI2 started 1 h before the LPS injection and was constant during the study period. RESULTS: Intracranial pressure increased significantly in animals treated with PGI2. The increase in ICP was associated with significant cerebral biochemical changes: decrease in glucose, increase in lactate, increase in lactate/glucose ratio and increase in glycerol. CONCLUSION: In LPS-induced brain oedema i.v. infusion of low-dose PGI2 caused a further increase in ICP and a perturbation of energy metabolism, indicating cerebral ischemia and degradation of cellular membranes.

Animals↗
PubMed2003

Volume-targeted therapy of increased intracranial pressure.

Fluid exchange across the intact blood-brain barrier (BBB) is counteracted by the low permeability to crystalloids (mainly Na+ and Cl-) combined with the high osmotic pressure (5,700 mm Hg) on both sides of the BBB. If the BBB is disrupted transcapillary water transport will be determined by the differences in hydrostatic and colloid osmotic pressure between the intra- and extracapillary compartments. Under these pathological conditions pressure autoregulation of cerebral blood flow is likely to be impaired and intracapillary hydrostatic pressure will depend on variations in systemic blood pressure. The volume targeted "Lund concept" can be summarized under four headings: A. Reduction of stress response and cerebral energy metabolism: B. Reduction of capillary hydrostatic pressure; C. Maintenance of colloid osmotic pressure and control of fluid balance: D. Reduction of cerebral blood volume. The efficacy of the protocol has been evaluated in experimental and clinical studies regarding the physiological and biochemical (utilizing intracerebral microdialysis) effects and the clinical experiences have been favourable.

Blood Pressure↗
PubMed2002

Correlation between blood glucose concentration and glucose concentration in subcutaneous adipose tissue evaluated with microdialysis during intensive care.

BACKGROUND: Hyper- as well as hypoglycemia may be detrimental for brain energy metabolism and even a moderate increase in blood glucose concentration can affect outcome adversely. During physiological conditions, glucose concentration obtained from microdialysis of subcutaneous adipose tissue adequately reflects plasma glucose concentration. This study examines whether this correlation is also obtained during intensive care in patients with severe injuries. METHODS: The study included 62 patients with severe traumatic brain injuries. All patients received one 30 mm microdialysis catheter (CMA 60, CMA Microdialysis) inserted into periumbilical subcutaneous adipose tissue. The probe was perfused (0.3 microl/min) with a Ringer solution from a microinfusion pump and analyzed for glucose, lactate, and glycerol. The study included 2.434 simultaneous analyses of glucose concentration in arterial blood and subcutaneous adipose tissue. RESULTS: The correlation coefficient for glucose concentration in blood and interstitial fluid was 0.743 for the whole material. The correlation was relatively poor for 1-6 h after insertion of the probes. During this period, a continuous increase in the subcutaneous level of glucose and decreases in lactate and glycerol were noted. CONCLUSIONS: The correlation between blood glucose concentration and glucose concentration in subcutaneous adipose tissue was not as good during intensive care as in normal humans. The poor correlation during the first 6 h probably reflects a stress reaction (and possibly local vasoconstriction). Microdialysis of subcutaneous adipose tissue permits frequent bedside analyses of the biochemical composition of the extracellular fluid and may be of value during routine intensive care provided the methodological limitations are recognized.

Adipose Tissue↗
PubMed2001

Brain energy metabolism during controlled reduction of cerebral perfusion pressure in severe head injuries.

OBJECTIVE: To study cerebral biochemical markers with intracerebral microdialysis and bedside analysis in patients with severe head injuries treated with a controlled reduction of cerebral perfusion pressure (CPP). DESIGN: Prospective observational study. SETTING: Neurological intensive care unit in a university hospital. PATIENTS: A consecutive series of 48 patients with severe head injuries and intracranial pressure (ICP) above 20 mmHg after conventional treatment. INTERVENTIONS: Reduction of CPP was attained with i. v. infusion of beta1-antagonist (metoprolol) and an alpha2-agonist (clonidine). One microdialysis catheter was inserted via a burr hole frontally to that used for the intraventricular catheter ("better" position). In 27 patients one or more catheters were inserted into cerebral cortex surrounding an evacuated focal contusion or underlying an evacuated haematoma ("worse" position). Perfusion rate was 0.3 microl/min and samples were taken every 30 or 60 min. The levels of glucose, pyruvate, lactate, glycerol and glutamate were analysed and displayed bedside. RESULTS: After initiation of treatment mean CPP decreased from 73 to 62 mmHg. During the first 96 h CPP was less than 60 mmHg and less than 50 mmHg during 30% and 8% of the time, respectively. The treatment was associated with a gradual normalisation of all biochemical markers in the "better" as well as the "worse" catheter position. CONCLUSION: The study shows that pharmacological decrease in CPP according to the "Lund concept" is associated with a normalisation of cerebral metabolism. The study also indicates that intracerebral microdialysis can be used for evaluation of new treatment strategies.

Adolescent↗
PubMed2001

Increased blood-brain barrier permeability of morphine in a patient with severe brain lesions as determined by microdialysis.

Intracerebral microdialysis was utilised to obtain information regarding how morphine is transported across the blood-brain barrier (BBB). In a patient with a severe brain injury, we measured simultaneously unbound extracellular fluid (ECF) concentrations of morphine in human brain and in subcutaneous fat tissue, which were compared to morphine levels in arterial blood. This report shows an increase in morphine levels near the trauma site in the brain compared to uninjured brain tissue. The half-life of morphine in uninjured and injured brain tissue of 178 min and 169 min, respectively, were comparable but were longer than in blood (64 min) and adipose tissue (63 min). This indicates that morphine is retained in brain tissue for a longer time than what could be expected from the blood concentration-time profile. These results show the potential of the microdialysis technique in providing new information regarding the pharmacokinetics of drug in the human brain close to the trauma site and in macroscopically intact tissue.

Blood-Brain Barrier↗
PubMed2001

Intracerebral microdialysis and bedside biochemical analysis in patients with fatal traumatic brain lesions.

BACKGROUND: Microdialysis with bedside biochemical analysis was used to monitor cerebral biochemical alterations that precede and accompany increase in intracranial pressure (ICP), resulting in a complete cessation of cerebral blood flow. METHODS: Seven patients, who died due to an untreatable increase in ICP, were included. The patients originate from a large, consecutive series of severely head injured patients (n: 95) monitored with intracerebral microdialysis (perfusion rate 0.3 microl/min). One microdialysis catheter was inserted via a separate burr hole frontally to that used for the intraventricular catheter ("better" position) and one catheter was inserted into cerebral cortex surrounding an evacuated focal contusion or underlying an evacuated haematoma ("worse" position). Biochemical analyses of glucose, lactate, glycerol, urea, glutamate, and pyruvate were performed at the bedside. All samples were frozen for subsequent HPLC (high-performance liquid chromatography) analyses of amino acids and ions. RESULTS: Decreases in glucose and pyruvate and increases in lactate, glycerol, glutamate, and lactate/pyruvate (la/py) ratio characterized cerebral ischaemia. The measured markers give information regarding substrate availability (glucose), redox state of the tissue (la/py ratio), degradation of glycerophospholipids in cell membranes (glycerol), and extracellular concentration of excitatory amino acids (glutamate). In the "worse" position biochemical deterioration occurred before the increase in ICP. In the "better" position biochemical deterioration was usually observed after the increase in ICP. CONCLUSION: Changes of cerebral energy metabolism that accompany cerebral ischaemia follow a certain pattern and may be detected at the bedside by intracerebral microdialysis before the secondary damage causes an increase in ICP.

Adult↗
PubMed2001

Neuropsychological assessments in relation to CBF after severe head injuries.

OBJECTIVE: To determine whether neuropsychological outcome is related to cerebral blood flow (CBF) early in the recovery phase. MATERIAL AND METHODS: Twelve consecutive patients (mean age of 30 years, range 15-48 years) with severe traumatic brain injuries were subjected to a neuropsychological test battery at admission to the rehabilitation unit and after 3, 6 and 12 months. CBF measurements were performed at admission and 6 and 12 months later with a high-resolution, two-dimensional regional cerebral blood flow system with 254 stationary detectors after 1 min of (133)Xe inhalation (70-100 MBq/l). RESULTS AND CONCLUSION: Mean CBF values were within normal range already in the early post-acute phase and remained virtually unchanged during the first year of rehabilitation. A correlation was found between the individual CBF level and neuropsychological outcome 1 year after injury, particularly with regard to verbal memory capacity, reasoning capacity, and information processing speed.

Adolescent↗
PubMed2001

Evaluation of surgery for acromegaly: role of intraoperative growth hormone measurement?

OBJECTIVE: Intraoperative growth hormone (GH ) measurement has earlier been tried to improve surgery for acromegaly. We calculated GH half-life after adenomectomy and evaluated the possible role of this variable in predicting the final outcome of pituitary surgery in 28 consecutive patients with acromegaly. The sensitivity, specificity and predictive values were determined in relation to the results from GH suppression during an oral glucose load and IGF-1 3 months postoperatively. The GH half-life data were also compared to the corresponding results obtained from GH measurements between 60 min and 180 min after adenomectomy, and early, within 1 week, postoperatively. RESULTS: GH half-life < or =31 min was recorded in 8/13 cured patients but also in 2/15 unsuccessful cases. A mean GH concentration < or =4.4 mU/L between 60 min and 120 min after adenomectomy was found in 11/13 cured subjects but also in 3/15 not cured patients. A mean GH < or =4.0 mU/L between 90 min and 180 min was found in 11/13 cured and in 4/15 not cured patients. A mean early postoperative GH concentration < or =2.6 mU/L was noted in all 13 cured patients, but also in 2/13 unsuccessful cases. The specificity of early postoperative GH < or = 2.6 mU/L was 100% compared to 62% for a GH half-life < or =31 min (p<0.05) and 85% for the GH mean values between 60 min and 120 min and 90 min and 180 min, respectively. The sensitivity for persistent disease of values above the four cut-off limits used was between 73% and 87%. The positive predictive value for a mean early postoperative GH value >2.6 mU/L was 100%, and 72% for a GH half-life >31 min (n.s.). CONCLUSION: Although intraoperative GH half-life might be useful in some cases, it was not a reliable tool for predicting outcome of pituitary surgery in acromegaly. In cases with a 51% decrease of a basal GH concentration >5.5 mU/L, mean GH values < or =4 to < or =4.4 mU/L late intraoperatively were more informative but not as good as those obtained from the mean of a series of GH values drawn on one occasion within 1 week postoperatively, offering a 100% specificity for cure if < or =2.6 mU/L. Intraoperative GH half-life measurements should therefore be used with caution. The predictive values of the cut-off limits used in this study should be further evaluated before general application.

Acromegaly↗
PubMed2000

Low-dose prostacyclin in treatment of severe brain trauma evaluated with microdialysis and jugular bulb oxygen measurements.

BACKGROUND: The endogenous substance prostacyclin is a substance with the potential to improve microcirculation and oxygenation around contusions in the brain following a head trauma by its vasodilatory, antiaggregatory and antiadhesive effects. Microdialysis measurements of local concentrations of selected interstitial substances in the brain, and measurements of venous jugular bulb oxygenation reflecting overall brain oxygenation, might be useful to evaluate possible therapeutic effects of a specific therapy, such as treatment with prostacyclin. METHODS: This case report study on six patients, of whom five were given prostacyclin, includes cerebral microdialysis measurements of interstitial lactate (n=5), pyruvate (n=3), glycerol (n=5) and glucose (n=4), and is combined with measurements of venous jugular bulb oxygenation in three of the patients. One microdialysis catheter was placed adjacent to a contusion, and in four of the patients another catheter was also placed in the contralateral less injured side for comparison. Low-dose prostacyclin infusion (0.5-1.0 ng kg(-1) min(-1)) was started when lactate concentrations in the more injured side was raised at a constant level for more than 10 h. The study also includes one patient used as control to whom no prostacyclin was given. RESULTS: Lactate was markedly lower in the less injured than in the more injured area of the brain. During the prostacyclin infusion elevated lactate and lactate/pyruvate ratio were reduced. Elevated glycerol decreased, a low glucose increased and jugular bulb blood oxygenation increased following start of prostacyclin. The control patient showed an increase in lactate and lactate/pyruvate ratio. CONCLUSION: The microdialysis data combined with the jugular bulb oxygenation data indicated that low-dose prostacyclin exerts effects compatible with improved oxygenation and reduced cell damage in the severely traumatised brain.

Adult↗
PubMed2000

Early postoperative growth hormone levels: high predictive value for long-term outcome after surgery for acromegaly.

OBJECTIVES: To explore the prognostic value of early - within 1 week - postoperative growth hormone (GH) measurements with regard to outcome after surgery for acromegaly in a short- and a long-term perspective. DESIGN: Retrospective study of patients operated on between 1987 and 1998, including follow-up for up to 60 months. SETTING: University hospital. SUBJECTS: Sixty-eight patients with acromegaly. INTERVENTION: Pituitary surgery aiming at adenomectomy with preservation of pituitary function. MAIN OUTCOME MEASURES: The effect of the operation was evaluated after 3 months, mostly by means of an oral glucose load or by insulin-like growth factor 1 (IGF-1). The specificity, sensitivity and the predictive values of an early postoperative mean GH concentration </= 4.8 mU L-1, as well as of the GH response to thyrotropin-releasing hormone (TRH) 3 months after surgery, were calculated with regard to outcome of the operation in both 3-month and long-term perspectives. RESULTS: Fifty patients (73.5%) showed a satisfactory effect at the evaluation 3 months postoperatively; 45 of these were followed between 12 and 60 months. Relapse was registered in five cases: 12, 12, 24, 24 and 48 months after surgery. In the long-term perspective, the predictive value of an early mean GH </= 4.8 mU L-1 was 93.6% with regard to a satisfactory effect of surgery, compared with 90.2% for a normalized somatomedin C (SmC)/IGF-1 and 90.0% for an absent GH response after TRH. An early mean GH > 4.8 mU L-1 had a 77.8% predictive value for persistent or recurrent disease, compared with 85.7% for persistently increased SmC/IGF-1 and 68.8% for an abnormal GH release after TRH 3 months after surgery. In the short-term perspective, the specificity and the predictive value of an early GH </= 4.8 mU L-1 were 77.3 and 97.1%, respectively. Early GH > 4.8 mU L-1 had a 94.4% sensitivity but a predicative value of only 63.0% for an unsatisfactory effect. CONCLUSION: Measurement of GH within 1 week after surgery is highly predictive for outcome of surgery for acromegaly. Specifically, an early mean GH </= 4.8 mU L-1 is as predictive for a satisfactory effect of treatment as a normalized IGF-1 3 months after surgery. Early postoperative GH values > 4.8 mU L-1 have a high sensitivity for persistent or recurrent disease in both the short- and long-term perspectives, but lower predictive value. The usefulness of the TRH test can be questioned.

Acromegaly↗
PubMed2000

Reduced mortality after severe head injury will increase the demands for rehabilitation services.

PRIMARY OBJECTIVE: In 1989, a new therapy to reduce intracranial pressure in severely head-injured patients was introduced in Lund. The new treatment reduced mortality significantly. The present study describes the quality of life for the survivors. METHODS AND PROCEDURES: The study includes 53 patients treated during 1989-1994, according to a new treatment protocol for increased intracranial pressure ('Lund concept' group). During 1982-1986, 38 patients were managed according to a protocol including high dose thiopentone ('Thiopentone' group). The two groups are compared regarding neurophysical and psychiatric symptoms as well as aspects regarding the patient's role, performance, interpersonal relationship, frictions, feelings and satisfaction in work, areas of social and leisure activities, and extended family. RESULTS: Mortality was reduced from 47% to 8%, but the number of patients with a persistent vegetative state and/or remaining severe disability did not increase. However, the number of patients with persisting emotional and intellectual deficits increased significantly. CONCLUSION: The new treatment regime has dramatically increased the number of survivors after severe head trauma. Although most patients have a favourable outcome, there are more patients with remaining sequelae and disabilities, and the demand for qualified rehabilitation has increased.

Adult↗
PubMed2000

Intracerebral microdialysis in clinical practice: baseline values for chemical markers during wakefulness, anesthesia, and neurosurgery.

OBJECTIVE: The study was undertaken to measure baseline values for chemical markers in human subjects during wakefulness, anesthesia, and neurosurgery, using intracerebral microdialysis. METHODS: Microdialysis catheters were inserted into normal posterior frontal cerebral cortex in nine patients who were undergoing surgery to treat benign lesions of the posterior fossa. The perfusion rate was 1.0 microl/min during anesthesia/neurosurgery and the early postoperative course and 0.3 microl/min during the later course. Bedside biochemical analyses of glucose, pyruvate, lactate, glycerol, glutamate, and urea were performed before, during, and after neurosurgery. After the bedside analyses, all samples were frozen for subsequent high-performance liquid chromatographic analyses of amino acids. RESULTS: The following baseline values were obtained during wakefulness (perfusion rate, 0.3 microl/min): glucose, 1.7+/-0.9 mmol/L; lactate, 2.9+/-0.9 mmol/L; pyruvate, 166+/-47 micromol/L; lactate/pyruvate ratio, 23+/-4; glycerol, 82+/-44 micromol/L; glutamate, 16+/-16 mmol/L; urea, 4.4+/-1.7 mmol/L. Marked increases in the levels of all chemical markers were observed at the beginning and end of anesthesia/surgery. CONCLUSION: The study provides human baseline levels for biochemical markers that can presently be measured at the bedside during neurointensive care. In addition, some changes that occurred under varying physiological conditions are described.

Adult↗
PubMed1998

Improved outcome after severe head injury with a new therapy based on principles for brain volume regulation and preserved microcirculation.

OBJECTIVE: To assess the new "Lund therapy" of posttraumatic brain edema, based on principles for brain-volume regulation and improved microcirculation. DESIGN: A prospective, nonrandomized outcome study over a 5-yr period on severely head-injured patients with increased intracranial pressure, comparing the results with a historical control group with the same selection criteria for patients who were treated according to conventional principles. SETTING: General intensive care unit of a university hospital. PATIENTS: Fifty-three consecutive head-injured patients with a Glasgow Coma Score of <8, and with increased intracranial pressure (>25 mm Hg), despite conventional treatment. INTERVENTIONS: Interstitial fluid resorption was obtained by lowering intracapillary hydrostatic pressure, by preserving normal colloid osmotic pressure, and by maintaining a normovolemic (normal albumin/serum and hemoglobin/serum), not overtransfused patient. Intracapillary pressure was reduced by the combination of precapillary vasoconstriction (low-dose thiopental, dihydroergotamine) and reduction of mean arterial pressure, the latter attained with a beta1-antagonist (metoprolol 0.2 to 0.3 mg/kg/24 hrs iv) and an alpha2-agonist (clonidine 0.4 to 0.8 microg/kg x 4 to 6 iv). Clonidine, in combination with normovolemia, also improves microcirculation by reducing catecholamines in plasma. Intracranial blood volume was reduced by arterial (low-dose thiopental sodium and dihydroergotamine) and large-vein (dihydroergotamine) vasoconstriction. The start dose of dihydroergotamine (maximum 0.9 microg/kg/hr) was successively reduced toward discontinuation within 4 to 5 days. MEASUREMENTS AND MAIN RESULTS: There were 8% of patients who died and the neurologic conditions of 13% remained severely damaged, compared with 47% and 11%, respectively, for the control group. CONCLUSIONS: The low mortality compared with previous outcome studies strongly indicates that this therapy improves outcome for severe head injuries. However, a randomized, controlled study is needed to reach general acceptance of this new therapy.

Acute Disease↗
PubMed1998

Postoperative prognosis in craniopharyngioma with respect to cardiovascular mortality, survival, and tumor recurrence.

Specific causes of death, survival, and recurrence rates were assessed in a cohort of 60 patients who had undergone surgery for craniopharyngioma between 1951 and 1988. Compared to the general population, the standardized mortality ratio (SMR) was increased [5.55; 95% confidence interval (CI), 3.68-8.22], and it was higher among females (SMR, 11.4) than males (SMR, 4.79). The risk of cardio- and cerebrovascular mortality (SMR, 3.21; 95% CI, 1.29-6.61) was also enhanced. The cumulative survival rates 10 and 15 yr after the initial operation were 68% (95% CI 54-78) and 59% (95% CI 30-63), respectively. A multivariate survival analysis adjusting for age showed a protective effect of radiotherapy (hazard ratio, 0.3; 95% CI, 0.1-0.8) and an increased risk of death after recurrence (hazard ratio, 4.4; 95% CI, 1.4-14), but no obvious effect of radicality at surgery. However, when patients who had died within 6 months after surgery were excluded, no significant protective effect of radiotherapy remained. The cumulative frequency of recurrence after 10 yr was 33% (95% CI, 22-48%), and that after 15 yr was 40% (95% CI, 28-56%). The incidence of recurrence did not differ significantly with respect to age, radicality at surgery, or postoperative radiotherapy. The determinants for long term outcome in patients with craniopharyngioma are interrelated in a complex way, which calls for strict selection criteria in follow-up studies and the use of multivariate statistical models.

Cardiovascular Diseases↗
PubMed1997

Increased cerebrovascular mortality in patients with hypopituitarism.

OBJECTIVE: An increased prevalence of atherosclerosis has been shown among patients with hypopituitarism. The aim of the present study was to assess whether patients with hypopituitarism experience increased cardiovascular, in particular cerebrovascular, mortality. DESIGN AND PATIENTS: Retrospective cohort study of mortality, 1952-1992, in 344 patients, of whom 130 were female, receiving conventional hormone replacement for hypopituitarism following neurosurgery for pituitary tumours. The general population in the catchment area of southern Sweden from which the patients were recruited constituted the reference population. Expected mortality was obtained from cause, sex, calendar year, and 5-year age-specific death raise for the area. RESULTS: Increased mortality from cerebrovascular disease (standardized mortality ratio (SMR) 3.39; 95% CI 2.27-4.99) was the main contributor to the increased overall cardiovascular mortality (SMR 1.75; 95% CI 1.40-2.19). The increase in mortality from cardiac diseases was much smaller (SMR 1.41; 95% CI 1.04-1.88). The risk for cerebrovascular death was higher in women (SMR 4.91) than in men (SMR 2.64). The relative risk for cerebrovascular death was independent of the time interval since diagnosis of pituitary insufficiency, but was greater in subjects diagnosed at an earlier age (< 55 years). No increased mortality in malignant tumours was observed (SMR 0.95; 95% CI 0.60-1.48). CONCLUSION: The increased cerebrovascular mortality may be due to GH deficiency, or to long-term lack or inadequacy of substitution for other pituitary hormones. The observations that an early onset of pituitary insufficiency and female sex are predictors for a high risk for cerebrovascular mortality merit particular attention when treating this group of patients.

Adult↗
PubMed1997

Time-dependency in brain lesion enhancement with gadodiamide injection.

PURPOSE: To determine the effective time window for MR imaging of tumors with blood-brain barrier (BBB) damage after injection of Gd-containing contrast media. MATERIAL AND METHODS: Eleven patients with 15 brain lesions (metastasis, glioma, abscess) were studied with a T1-weighted spin-echo sequence repeated over periods of up to 43 min after contrast injection. A quotient was calculated between the signals in the lesion and in the gray matter, and plotted against time. RESULTS: All lesions reached 70% of the maximum RATIO within 3.5 min. After 25 min 12 out of 15 lesions showed persistent enhancement within 15% of the maximal RATIO. CONCLUSION: The peak enhancement of BBB damage occurs around 3.5 min after injection. The effect does not change during the next 25 min. Scanning should not be started until 2-5 min after injection of the contrast medium, and there is no advantage in waiting longer as no major increase (or decline) of contrast can be expected.

Adult↗