Knut Brabrand

Oslo University Hospital, Kristiania (historical), Oslo County, Norway

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Publications (34)82.64 Total impact

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    ABSTRACT: In patients with type 1 diabetes and end-stage renal disease (ESRD) we aimed to determine whether long-term normoglycaemia, as achieved by successful simultaneous pancreas and kidney (SPK) transplantation, would preserve kidney graft structure and function better than live donor kidney (LDK) transplantation alone.
    Diabetologia 08/2014; · 6.49 Impact Factor
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    ABSTRACT: It is well known from both clinical experience and animal research that renal hypoxia may lead to temporary or permanent renal failure, the severity being dependent largely on the duration and grade of the hypoxia. The medulla is more susceptible to hypoxic injury than the cortex because approximately 90% of the renal blood flow supplies the cortex. Various methods have been applied to evaluate renal perfusion in both experimental and clinical settings, including magnetic resonance imaging, computed tomography, laser Doppler, and contrast-enhanced ultrasound (CEUS). The aim of this study was to evaluate changes in overall and regional renal perfusion with CEUS in response to global hypoxia. Twelve newborn anesthetized piglets were exposed to general hypoxia with a fraction of inspired oxygen of 8% of 30 minutes duration. Resuscitation was performed with either 100% oxygen (n = 6) or air (21% oxygen) (n = 6) for 30 minutes followed by 7 hours of reoxygenation with air. Before, during, and after hypoxia, the left kidney was examined with CEUS using 0.2 mL IV of SonoVue followed by 2 mL saline flush. Five additional piglets served as controls. The kidney was examined using a 9-MHz linear transducer with low mechanical index (0.21) and pulse inversion contrast program. One region of interest was drawn in the renal cortex and 1 in the medulla to obtain the corresponding time intensity curves (TICs). From these curves, the peak intensity (PI), time to peak (TTP), upslope of the curve, area under the curve, and mean transit time (MTT) were recorded. Also, the renal arteriovenous transit time (AVTT) was registered. The resistance index (RI) was repeatedly measured in the renal artery. Contrast-enhanced ultrasound was repeated at regular intervals until the animals were sacrificed 8 hours after the hypoxic period. In the group of 12 piglets subjected to hypoxia, RI increased from 0.69 ± 0.08 at baseline to 0.99 ± 0.09 during hypoxia (P < 0.01), indicating severe general renal vasoconstriction. The AVTT increased from 2.6 ± 0.5 seconds at baseline to 6.7 ± 2.8 seconds during hypoxia (P < 0.001). The PI in the cortex decreased from a mean value of 38.6 ± 6.1 dB at baseline to 30.3 ± 9.7 dB during hypoxia (P < 0.05). In the medulla, only a minor, nonsignificant reduction in PI was observed during hypoxia. In the medulla, TTP and MTT increased from 6.4 ± 1.5 and 9.2 ± 1.7 seconds at baseline to 14.6 ± 8.4 seconds (P < 0.01) and 15.2 ± 5.6 seconds (P < 0.01), respectively, during hypoxia. In the cortex, no statistically significant changes in TTP or MTT were observed during hypoxia. A return to near-baseline values was observed for TTP, PI in both the medulla and cortex, as well as for RI and AVTT within 1 to 3 hours after hypoxia, and they remained relatively constant for the duration of the experiment.Less than 1 hour after the hypoxia, PI both in the cortex and the medulla was significantly higher in the group resuscitated with air than in the group resuscitated with 100% oxygen, 36.0 ± 4.3 versus 27.2 ± 2.2 dB (P < 0.05) and 33.3 ± 8.2 versus 21.1 ± 2.0 dB (P < 0.01), respectively. Global hypoxia induced changes in overall and regional renal perfusion detectable with CEUS. Cortical and medullary flows were affected differently by hypoxia; a strong increase in medullary TTP and MTT was observed, indicating a reduction in medullary blood flow velocity. In the cortex, a significant reduction in PI was found, probably because of a reduction in cortical blood volume. A faster recovery of both medullary and cortical PI in the group resuscitated with air could indicate that air might be more beneficial for renal perfusion than hyperoxia during resuscitation after renal hypoxia.
    Investigative radiology 03/2014; · 4.85 Impact Factor
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    ABSTRACT: BACKGROUND.: Color Doppler ultrasound (CDUS) has a potential of early detection of post biopsy bleeding. We describe CDUS guidance in planning, acquisition, and, in the case of bleeding, compression of the needle tract in biopsy procedures of kidney transplants. METHODS.: Eighty-three kidney transplant biopsy procedures performed on clinical indication were performed in 71 adult patients, 25 women, mean age 51 years, using CDUS and 18-G biopsy needles. Bleeding needle tracts were compressed using CDUS guidance. RESULTS.: CDUS immediately detected blood leakage and facilitated compression of the bleeding needle tract in 34 (41%) of the 83 procedures, including 53 (25%) of 215 needle passes. In 34 bleeding procedures, the mean duration of the longest bleeding time after a needle pass was 124 seconds (median, 20 seconds; range, 3-1440 seconds). In 12 of these procedures (35%), the bleeding time was 30 seconds or more. In six procedures (18%), a bleeding of 120 seconds or more was observed. Complications included seven small hematomas. Five hematomas developed in procedures where the longest duration CD bleeding was 120 seconds or more. CONCLUSIONS.: CDUS detects bleeding and facilitates direct transducer compression of the needle tract in a substantial portion of biopsy procedures of kidney transplants. Only minor hematomas occurred. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2012.
    Journal of Clinical Ultrasound 08/2012; · 0.70 Impact Factor
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    ABSTRACT: Acoustic radiation force impulse (ARFI) quantification estimates tissue elasticity by measuring shear-wave velocity (SWV) and has been applied to various organs. We evaluated the impact of variations in the transducer force applied to the skin on the SWV ultrasound measurements in kidney transplant cortex and ARFI's ability to detect fibrosis in kidney transplants. SWV measurements were performed in the cortex of 31 patients with kidney allografts referred for surveillance biopsies. A mechanical device held the transducer and applied forces were equal to a compression weight of 22, 275, 490, 975, 2,040 and 2,990 g. SWV group means were significantly different by repeat measures ANOVA [F(2.85,85.91) = 84.75, P < 0.0005 for 22, 275, 490, 975 and 2,040 g compression weight] and also by pairwise comparisons. Biopsy specimens were sufficient for histological evaluation in 29 of 31 patients. Twelve had grade 0, 11 grade 1, five grade 2 and one grade 3 fibrosis. One-way ANOVA showed no difference in SWV performed with any of the applied transducer forces between grafts with various degrees of fibrosis. SWV measurements in kidney transplants are dependent on the applied transducer force and do not differ in grafts with different grades of fibrosis. • Acoustic radiation force impulses (ARFI) can quantify tissue elasticity during ultrasound examinations. • Elasticity estimated by ARFI in kidney transplants depends on applied transducer force. • ARFI quantification cannot detect renal allograft fibrosis. • ARFI elasticity estimates may in general vary with applied transducer force.
    European Radiology 05/2012; 22(10):2130-7. · 4.34 Impact Factor
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    ABSTRACT: Chronic allograft nephropathy (CAN) characterized by interstitial fibrosis and tubular atrophy is a major cause of renal transplant failure. The diagnosis can currently only be verified by a graft biopsy. To evaluate whether non-invasive dynamic color Doppler sonographic parenchymal perfusion measurements are different in grafts with various degrees of biopsy proven renal transplant fibrosis. Forty-nine adult patients were prospectively included. Four patients were excluded. Color Doppler videos from the renal cortex were recorded. Perfusion in the renal cortex was evaluated using a software package which calculates color pixel area and flow velocity, encoded by each pixel inside a region of interest of a video sequence. The software calculates parameters that describe tissue perfusion numerically. Two of these, the perfusion intensity and tissue pulsatility index, were compared to grade of interstitial fibrosis (0-3) in biopsies. Observer agreement was evaluated in a subset of 12 patients. Of the 45 patients analyzed, 18 patients had grade 0, 18 had grade 1, seven had grade 2 and two had grade 3 fibrosis. The mean perfusion intensity of grade 0 was significantly higher than that of grade 2 and 3 fibrosis in the proximal cortical layer (1.65 m/s vs. 0.84 m/s, P = 0.008). No significant difference was found between grade 0 and grade 1 fibrosis. Perfusion intensity was correlated to estimated glomerular filtration rate (Pearson r 0.51, P = 0.001, R(2) = 0.26 and 0.46, P = 0.001, R(2) = 0.22 in the distal and proximal cortex, respectively). Inter-observer agreement of the perfusion intensity, expressed as intraclass correlation coefficient was 0.69 in the proximal part of the cortex. Intra-observer agreement was 0.85 for observer 1 and 0.82 for observer 2. Perfusion intensity assessed by dynamic color Doppler measurements is significantly reduced in allografts with grade 2 and 3 fibrosis compared to allografts without fibrosis. Further studies involving longitudinal assessment of allografts undergoing protocol biopsies would be of interest.
    Acta Radiologica 08/2011; 52(8):920-6. · 1.33 Impact Factor
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    ABSTRACT: Cerebrovascular factors are crucially involved in the early injury after perinatal asphyxia. With magnetic resonance imaging (MRI) and ultrasonography (US), this study aimed to quantify microvascular perfusion changes due to hypoxia and resuscitation, by comparing contrast-enhanced ultrasound (CEUS) to dynamic susceptibility contrast-enhanced (DSC)-MRI and diffusion-weighted MRI. Newborn piglets (n = 12/17) were reoxygenated with 21% (n = 6) or 100% O2 (n = 6) after global hypoxia. Five piglets served as controls. CEUS and MRI were performed before, during, and up to 7 hours after hypoxia. Following are the perfusion parameters for CEUS: peak intensity (PI), area under the curve (AUC), time to peak (TTP), and upslope a and perfusion/diffusion parameters for MRI: relative cerebral blood volume, relative cerebral blood flow, mean transit time, and apparent diffusion coefficient were compared between different regions in the brain across time points and also compared with histology at the end. In CEUS, compared with the control group, perfusion changed significantly over time, in the hyperoxic group in all regions for PI, AUC in all regions of interests. The changes presented mainly as decreased perfusion during and shortly after resuscitation: for PI in the basal ganglia (BG), cortex, and the whole brain with 50 to 60% (P ≤ 0.001); for AUC in the BG and cortex with 90% (P ≤ 0.02) and in the whole brain with 70% (P = 0.004). In the injured brains (confirmed by histology), significant changes over time were seen in TTP and AUC with mainly increased perfusion during hypoxia: for TTP in the cortex, AUC in the BG and whole brain with 90 to 100% (P ≤ 0.04), and for TTP in the whole brain with 50% (P = 0.02). DSC-MRI showed the same trends in perfusion with regard to relative cerebral blood volume as CEUS. In all pigs exposed to hypoxia, perfusion returned toward baseline values at 7 hours after hypoxia in both methods. Apparent diffusion coefficient decreased significantly after 7 hours in the injured brains in the BG from 114.6 ± 1.2 × 10mm/s to 90.3 ± 24 × 10 mm/s (P = 0.03). CEUS and DSC-MRI can detect an early temporal evolution of cerebral perfusion in perinatal hypoxia and resuscitation, reversible after 7 hours. Hyperoxic resuscitation caused early decreased cerebral perfusion, not present in the normoxic group. The combined use of CEUS and DSC-MRI can provide important diagnostic information and give new insights into perinatal vascular hypoxia mechanisms.
    Investigative radiology 07/2011; 46(11):686-96. · 4.85 Impact Factor
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    ABSTRACT: Formation of lymphocele (accumulation of lymphatic fluid) is a common surgical complication following kidney transplantation. This open randomized trial evaluated the effect of prophylactic fenestration on lymphocele formation. Adult recipients of kidney grafts from deceased donors were randomized to undergo peritoneal fenestration during the transplantation or to standard surgical procedure without fenestration. The incidence of symptomatic lymphocele in the two groups was compared at 1 year after transplantation. A protocol-based ultrasound examination was performed in the 1st, 5th, and 10th postoperative week. Any hypoechoic perirenal collection was registered. One hundred thirty recipients were randomized to peritoneal fenestration (n = 69) or standard therapy (n = 61). Six patients were excluded. Nine of 58 (15.5%) patients in the standard group developed symptomatic lymphoceles requiring treatment during the first postoperative year, versus 2 of 66 (3.0%) in the fenestration group (relative risk = 0.20, 95% confidence interval: 0.04-0.82, P = 0.015). Seven major surgical procedures and five percutaneous drainages due to lymphoceles were performed in the standard group, compared with two percutaneous drainages in the fenestration group. The prevalence of fluid collections in the fifth postoperative week was significantly higher in the standard group (66% vs. 37%; relative risk = 0.57, 95% confidence interval: 0.37-0.71, P = 0.005). Prophylactic fenestration reduced the risk of lymphoceles and the need for invasive procedures to treat this condition. The results need to be confirmed in a population of transplant recipients on lower steroids and with the use of wound drains.
    Transplantation 05/2011; 92(2):196-202. · 3.78 Impact Factor
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    ABSTRACT: To conduct a dose testing analysis of perfluorobutane microbubble (NC100100) contrast-enhanced ultrasound (CEUS) to determine the optimal dose for detection of liver metastases in patients with extra-hepatic primary malignancy. 157 patients were investigated with conventional US and CEUS. CEUS was performed following intravenous administration of perfluorobutane microbubbles (using one dose of either 0.008, 0.08, 0.12 or 0.36 μL/kg body weight). Three blinded off-site readers recorded the number and locations of metastatic lesions detected by US and CEUS. Contrast enhanced CT and MRI were used as the "Standard Of Reference" (SOR). Sensitivity, specificity and accuracy of liver metastasis detection with US versus CEUS, for each dose group were obtained. Dose group analysis was performed using the Chi-square test. 165 metastases were present in 92 patients who each had 1-7 lesions present on the SOR. Sensitivity of US versus CEUS (for all doses combined) was 38% and 67% (p = 0.0001). The 0.12 dose group with CEUS (78%) had significantly higher sensitivity and accuracy (70%) compared to other dose groups (p < 0.05). The diagnostic performance of CEUS is dose dependent with the 0.12 μL/kg NC100100 dose group showing the greatest sensitivity and accuracy in detection of liver metastases.
    European Radiology 04/2011; 21(8):1739-46. · 4.34 Impact Factor
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    ABSTRACT: There is limited knowledge about the incidence, clinical implication and spontaneous course of transplant renal artery stenosis detected early after renal transplantation. We performed Doppler ultrasound examination of the transplant artery(s) 2 months after transplantation in 98 consecutive patients and peak systolic velocity (PSV) was measured. All patients with an elevated PSV ≥1.8 m/s were reexamined 20 months later and clinical data were followed for 3 years. At the initial examination 2 months after transplantation 15 recipients had a PSV ≥1.8 m/s, mean value for PSV 2.5 (1.8-3.6) m/s, whereas 83 recipients had a normal PSV of 1.3 (0.7-1.7) m/s (P<0.01). At baseline there were no statistical significant differences in clinical parameters between the high PSV versus normal PSV recipients. Twenty (15-28) months after transplantation 14 patients with initial elevated PSV were re-examined. There was an overall mean reduction in PSV of 0.5 (-0.7 to 1.2) m/s from 2.4 (1.8-3.4) m/s to 1.9 (1.2-3.1) m/s (P=0.02). Detection of a high PSV early after transplantation did not affect graft function or blood pressure 3 years after engraftment. We conclude that a high PSV, at 2 months after engraftment, seems to be more of an 'incidental finding' that should be re-challenged and carefully interpreted.
    Transplant International 02/2011; 24(6):555-9. · 3.16 Impact Factor
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    ABSTRACT: Chronic allograft nephropathy characterized by interstitial fibrosis and tubular atrophy is a major cause of renal transplant failure. Acoustic radiation force impulse (ARFI) quantification is a promising noninvasive method for assessing tissue stiffness. We evaluated if the method could reveal renal transplant fibrosis. In a prospective study, 30 adult renal transplant recipients were included. ARFI quantification, given as shear wave velocity (SWV), of the renal cortex was performed by two observers. SWV was compared to grade of fibrosis (0-3) in biopsies. The median SWV was 2.8 m/s (range: 1.6-3.6), 2.6 m/s (range: 1.8-3.5) and 2.5 m/s (range: 1.6-3) for grade 0 (n = 12), 1 (n = 10) and grades 2/3 (n = 8) fibrosis respectively. SWV did not differ significantly in transplants without and with fibrosis (grade 0 vs. grade 1, P = 0.53 and grade 0 vs. grades 2/3, P = 0.11). The mean intraobserver coefficient of variation was 22% for observer 1 and 24% for observer 2. Interobserver agreement, expressed as intraclass correlation coefficient was 0.31 (95% CI: -0.03 to 0.60). This study does not support the use of ARFI quantification to assess low-grade fibrosis in renal transplants. ARFI quantification in its present stage of development has also high intra- and interobserver variation in renal transplants.
    Transplant International 01/2011; 24(1):100-5. · 3.16 Impact Factor
  • Transplantation 01/2010; 90. · 3.78 Impact Factor
  • Transplantation 01/2010; 90. · 3.78 Impact Factor
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    ABSTRACT: PURPOSE Evaluation of regional renal perfusion changes with contrast enhanced ultrasound (CEUS) as a response to general hypoxia. METHOD AND MATERIALS 12 newborn anaesthetized piglets were exposed to general hypoxia (FiO2=8%) of 30 minutes duration. Before, during and after hypoxia the kidneys were examined with CEUS using SonoVue 0.2 ml i.v. followed by 2 ml saline flush. 5 piglets served as controls. The kidneys were examined with a 9MHz linear transducer with pulse inversion technique and low mechanical index (Cadence,Siemens Acuson Sequoia, Erlangen, Germany). Video clips of 20 second duration were analyzed with special perfusion software (ACQ, Siemens) and one region of interest (ROI) was drawn in the renal cortex and in one the medulla. From the time intensity curves the time to peak (TTP) and peak intensity (PI) were recorded. In order to evaluate regional perfusion changes the quotient of the perfusion parameter TTP in cortex and medulla was calculated. The resistance index (RI) was repeatly measured in a segmental artery. The results in the different groups were compared using the Mann–Whitney U-test for unpaired samples. Significance was set at P<0.05. <0> RESULTS The ratio TTP medulla/TTP cortex increased from 1.26 (0.73-1.70) at baseline to 2.29 (0.86-4.83) during hypoxia (borderline significant, P=0.04) indicating that the microbubble velocity decreased more in the medulla than in the cortex. A return to near baseline values was observed 1-3 hours following hypoxia. RI increased from 0.69 (0.56- 0.81) at baseline to 0.99 (0.86-1.15) during hypoxia (P=0.005) indicating severe renal vasospasm. RI returned to near baseline values within one hour after the end of hypoxia. CONCLUSION CEUS enables detection and quantification of regional renal perfusion changes during general hypoxia. During hypoxia there was a borderline significant increase in the ratio TTP medulla/TTP cortex indicating a more pronounced decrease in microbubble velocity in the medulla. This could be in accordance with the observation that renal hypoxia of limited duration more often leads to medullar changes (acute tubular necrosis) than cortical necrosis. CLINICAL RELEVANCE/APPLICATION CEUS enables detection and quantification of regional renal perfusion changes during general hypoxia.
    Radiological Society of North America 2009 Scientific Assembly and Annual Meeting; 11/2009
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    ABSTRACT: To evaluate the frequency of use and the diagnostic accuracy of real-time contrast-enhanced ultrasound (CEUS) in the diagnosis of hepatic artery occlusion after liver transplantation. One hundred and fifty-two liver transplantations in 142 adult subjects, comprising 80 male patients and 62 female patients, were studied. After surgery, liver circulation was routinely assessed by conventional Doppler ultrasound (US). Wherever the examiners were not confident about the state of the circulation, CEUS was performed with one or more doses of a sulfur hexafluoride (SF-6)-containing second-generation contrast agent intravenously. Clinical follow up including repeat Doppler US, computed tomographic angiography (CTA) or magnetic resonance angiography (MRA) of the liver vasculature were used as reference standards. During the first month after transplantation, Doppler US was inconclusive with regard to patency of the hepatic artery (HA) circulation in 20 (13 %) of 152 transplantations. CEUS was performed in these patients, and detected six cases of HA thrombosis (HAT) in five transplants. CEUS correctly ruled out HA occlusion in 15 transplants. All HA occlusions occurred during the first 14 days after transplantation. In the subset of transplantations examined with CEUS, the sensitivity, specificity and accuracy of CEUS were 100%. In approximately 13% of cases, conventional Doppler US did not provide sufficient visualization of the HA after liver transplantation. In these cases, correct diagnosis was achieved by supplementary CEUS.
    Transplant International 06/2009; 22(10):954-60. · 3.16 Impact Factor
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    ABSTRACT: Paediatric kidneys transplanted to adult recipients increase in size after transplantation. It is unknown if the renal artery diameter increases concomitantly with the kidney. This study was performed to assess if peak systolic velocity (PSV) in the renal arteries of paediatric kidneys transplanted to adult recipients is comparable to PSV in the renal arteries of adult kidneys transplanted to adult recipients. Subjects and methods. Fifteen adult patients with paediatric renal transplants were examined with ultrasound Doppler and compared with a control group of adult recipients with adult transplants. MR angiography (MRA) or intra-arterial angiography (IA) was performed in patients with elevated PSV. MRA renal diameters of the paediatric transplants were compared with adult transplants. The mean maximum PSV of the paediatric kidneys was 2.0 m/s (0.9-3.8), almost twice compared with the adult grafts transplanted to adult recipients, 1.1 m/s (0.7-1.6), P < 0.001. Seven paediatric transplants had a PSV >1.8 m/s, but only two had significant stenosis on MRA/IA. All patients had excellent blood pressure and renal function. The mean diameter of the paediatric renal arteries was 4.1 mm (3.4-6.0), whereas the mean for the adult renal arteries was 5.6 mm (4.8-6.9), P = 0.02. Adult recipients of paediatric kidneys have significantly higher maximum PSV in the renal artery compared to adult recipients of adult grafts. The significantly smaller renal artery diameter might explain the high PSV. A PSV >1.8 m/s by itself does not necessarily indicate transplant renal artery stenosis in paediatric kidneys transplanted to adult recipients, but should be related to clinical findings.
    Nephrology Dialysis Transplantation 06/2008; 23(12):4041-3. · 3.37 Impact Factor
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    ABSTRACT: Radiofrequency (RF) ablation is a method that uses electrical current for thermal destruction of solid tumours. We present our experience with RF ablation in a patient population with non-resectable colorectal liver metastases. 17 of the 23 patients with non-resectable liver metastases treated with RF ablation at Rikshospitalet University Hospital from 2003 to 2006, were included in a prospective non-randomized study with standardized follow-up. RF ablation was used to treat one liver metastasis in each patient, and was combined with liver resection in seven patients. The median follow-up time after RF ablation was 29 months (14-55). One-year survival was 100% and survival after both two and three years was 67%. Follow-up examinations revealed local tumour progression at the RF-treated site in eight patients, intrahepatic recurrences not related to the RF-treated site in eight patients and extrahepatic recurrence in nine patients. Four patients with intrahepatic recurrence were re-treated with a curative intent. Long-term survival is possible after RF ablation of selected patients with non-resectable colorectal liver metastases. Local tumour progression, intrahepatic- and extrahepatic tumour recurrence is common after RF ablation. Systematic follow-up can identify tumour recurrences that may be re-treated with a curative intent. Liver resection should still be considered the gold standard for patients with resectable colorectal liver metastases.
    Tidsskrift for den Norske laegeforening 02/2008; 128(1):57-60.
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    ABSTRACT: We have earlier shown an increase in the size and excellent graft function of paediatric kidneys transplanted to adults up to 1 year following transplantation. This study was performed to assess the long-term outcome of these transplants. From a primary cohort of 19 adults, receiving a first kidney transplant from a paediatric donor <10 years of age, 16 patients were available for a complete long-term follow-up, 5-9 years post-transplant. Of these, eight patients were transplanted with a donor of <5 years. All medical files and registry data of the cohort, from the time of transplantation to the follow-up time point, were recalled and events were registered. The patients' general condition, body weight, blood and urine tests, blood pressure (BP), use of antihypertensive agents and GFR were recorded. To explore the temporal increment in the size of paediatric donor kidneys transplanted to adults, the maximal cranio-caudal length of the kidneys from the time of transplantation to follow-up was established by ultrasound. Volumes (length x width x thickness x pi/6) of en bloc kidneys versus single paediatric kidneys and adult-to-adult transplants were compared. Long-term (7 years, median) patient and graft survival was 95% and 89%, respectively. Mean serum creatinine was 85 micromol/l (range, 32-131). The mean estimated GFR was 84 ml/min/1.73 m(2). The mean BP was 134/79 mmHg (range, 120-185/70-90). The number of antihypertensive agents used was not statistically different from the number used at 1 year post-transplant. None of the patients had significant proteinuria as a sign of hyperfiltration injury of the graft. There were no statistically significant increases in the maximal cranio-caudal length of the transplanted kidney(s) from 1 year post-transplant to follow-up; however, the en bloc kidneys tended to be larger than single paediatric grafts (240 ml and 204 ml) and adult-to-adult grafts (170 ml). Paediatric kidneys transplanted to adults should be considered as excellent for transplantation on a long-term basis.
    Nephrology Dialysis Transplantation 02/2008; 23(2):726-9. · 3.37 Impact Factor
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    ABSTRACT: PURPOSE The utility of contrast-enhanced ultrasound (US) for vascular visualization after liver transplantation in a clinical setting was examined. METHOD AND MATERIALS From September 2004 to February 2006, 56 adult patients were liver transplanted in our hospital (median 47 years, range 19 to 71, 33 were men). After surgery, the hepatic artery (HA), portal vein (PV) and liver veins were routinely assessed by conventional Doppler US using an Aquson Sequoia machine. The HA was assessed both extra- and intrahepatically. If the examiner was not confident about the state of the vessels, contrast-enhanced US was performed by an experienced radiologist using one or more doses of SonoVue (Bracco, Italy) intravenously. CT or MR of the liver vasculature was used as a reference standard. RESULTS A total of 443 Doppler US examinations were performed (median 6 per patient, range 1 to 31). Conventional Doppler US was inconclusive in 13 (3%) of examinations, and in 10 of 56 (18%) patients. Insufficient visualization included the HA in 8 of these 10 patients. However, contrast-enhancement enabled documentation of an open HA in all these. HA was very small in one, and the signal suggestive of stenosis in another. An open HA was confirmed the next day by CT or MR in 7, and by conventional ultrasound in the remaining patient. The PV could not be adequately assed by conventional Doppler US in two patients (4%). Contrast enhancement revealed portal venous thrombus in one patients and an open vein with sharp bend in the other, each of the findings confirmed by MR. CONCLUSION In most cases (approximately 80%), conventional Doppler US was sufficient to document open vessels after liver transplantation. Supplementary contrast-enhanced US provided correct information in the remaining patients. CLINICAL RELEVANCE/APPLICATION Contrast-enhanced US was a valuable supplement to conventional Doppler US in approximately 20% of patients after liver transplantation.
    Radiological Society of North America 2007 Scientific Assembly and Annual Meeting; 11/2007
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    ABSTRACT: Detection of local tumor progression (LTP) after radiofrequency (RF) ablation of colorectal cancer liver metastases may facilitate repeat intervention with potential benefits for patient survival. Ablative margins 1 month after RF ablation may predict LTP, and repeated three-dimensional (3D) volumetric analysis of coagulation volume after ablation may provide earlier detection of LTP versus conventional morphologic criteria. Seven patients with LTP and four patients without LTP after a follow-up of at least 24 months were identified. Multidetector computed tomography (CT) was performed at 1 and 3 months after RF ablation and then at 3-month intervals until 24 months. Ablative margins were determined from preablation tumor diameter and the corresponding coagulation diameter 1 month after ablation. Postablation coagulation volume was measured from 81 follow-up multidetector CT images using a seeding-based semiautomatic 3D method. LTP was detected at a median of 9 months (range, 6-21 months) after RF ablation. A coagulation diameter smaller than the preoperative tumor diameter was associated with LTP. Increase in coagulation volume was found in six of seven patients at the time of diagnosis of LTP by conventional morphologic criteria. Three-dimensional volumetric analysis of postablation coagulation volume is feasible for detection of LTP after RF ablation of colorectal cancer liver metastases. No advantage in early detection of LTP was found for 3D volumetric analysis compared with conventional morphologic criteria in this preliminary study. These findings may reflect a type II error caused by the limited sample size.
    Journal of Vascular and Interventional Radiology 10/2007; 18(9):1134-40. · 2.00 Impact Factor
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    ABSTRACT: There is increasing evidence that paediatric kidneys transplanted to adults have good graft function and satisfactory graft survival. The relationship between size increment and functional potential of paediatric kidneys following transplantation is not defined in detail. We therefore initiated a prospective single centre study, comprising detailed and repeated measurements of size and function of paediatric kidneys transplanted to adults. Nineteen adults receiving a first kidney transplant from a paediatric donor (<10 years of age) were included in the study. All patients were followed for 12 months post-transplant. Increment in size and function of the transplanted kidneys were assessed by ultrasound, glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). All tests were performed during the first week, post-transplant and subsequently repeated at 1, 3, 6 and 12 months. Kidney volume increased 2.6-fold at 12 months (P < 0.001). GFR and ERPF showed a slightly more moderate increase, 1.8-fold and 1.6-fold, respectively. Patient and graft survival at 1 year were 100% and serum creatinine was 91 micromol/l (66-169). The study indicates that paediatric kidneys for transplantation may be considered as excellent rather than being referred to as suboptimal for adult recipients, at least the first year after transplantation.
    Nephrology Dialysis Transplantation 07/2007; 22(6):1738-42. · 3.37 Impact Factor