Knut Brabrand

Assessment of renal allograft fibrosis by acoustic radiation force impulse quantification--a pilot study.

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.

Enhanced liver fibrosis score predicts transplant-free survival in primary sclerosing cholangitis.

There is a need to determine biomarkers reflecting disease activity and prognosis in primary sclerosing cholangitis (PSC). We evaluated the prognostic utility of the enhanced liver fibrosis (ELF) score in Norwegian PSC patients. Serum samples were available from 305 well‐characterized large‐duct PSC patients, 96 ulcerative colitis patients, and 100 healthy controls. The PSC patients constituted a derivation panel (recruited 1992‐2006 [n = 167]; median age 41 years, 74% male) and a validation panel (recruited 2008‐2012 [n = 138]; median age 40 years, 78% male). We used commercial kits to analyze serum levels of hyaluronic acid, tissue inhibitor of metalloproteinases‐1, and propeptide of type III procollagen and calculated ELF scores by the previously published algorithm. Results were also validated by analysis of ELF tests using the ADVIA Centaur XP system and its commercially available reagents. We found that PSC patients stratified by ELF score tertiles exhibited significantly different transplant‐free survival in both panels (P < 0.001), with higher scores associated with shorter survival, which was confirmed in the validation panel stratified by ELF test tertiles (P = 0.003). The ELF test distinguished between mild and severe disease defined by clinical outcome (transplantation or death) with an area under the curve of 0.81 (95% confidence interval [CI] 0.73‐0.87) and optimal cutoff of 10.6 (sensitivity 70.2%, specificity 79.1%). In multivariate Cox regression analysis in both panels, ELF score (hazard ratio = 1.9, 95% CI 1.4‐2.5, and 1.5, 95% CI 1.1‐2.1, respectively) was associated with transplant‐free survival independently of the Mayo risk score (hazard ratio = 1.3, 95% CI 1.1‐1.6, and 1.6, 95% CI 1.2‐2.1, respectively). The ELF test correlated with ultrasound elastography in separate assessments. Conclusion: The ELF score is a potent prognostic marker in PSC, independent of the Mayo risk score. (Hepatology 2015;62:188‐197)

EFSUMB Guidelines on Interventional Ultrasound (INVUS), Part II. Diagnostic Ultrasound-Guided Interventional Procedures (Long Version).

This is the second part of the series on interventional ultrasound guidelines of the Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB). It deals with the diagnostic interventional procedure. General points are discussed which are pertinent to all patients, followed by organ-specific imaging that will allow the correct pathway and planning for the interventional procedure. This will allow for the appropriate imaging workup for each individual interventional procedure (Long version).

Clinical utility of microbubble contrast‐enhanced ultrasound in the diagnosis of hepatic artery occlusion after liver transplantation

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.

Complications Following Ultrasound‐Guided Thoracocentesis

Purpose: To retrospectively register the number and type of complications following ultrasound‐guided thoracocentesis, and to evaluate the need for routine chest X‐ray after the procedure. Material and Methods: Complications were retrospectively registered from the radiological and clinical reports of 371 consecutive patients who had undergone thoracocentesis with a total of 711 procedures. Results: The mean volume evacuated was 823 ml (range 0–3600 ml). Twenty (2.8%) pneumothoraces were found after 711 thoracocenteses, but in no case was chest tube drainage necessary. Hemoptysis occurred in one patient. Conclusion: Ultrasound‐guided thoracocentesis was found to be a safe procedure. Based on these results, no reason was found to introduce an upper limit of the amount of fluid drained in one session. Routine follow‐up chest X‐ray is not justified in the absence of clinical symptoms.

Non-invasive assessment of renal allograft fibrosis by dynamic sonographic tissue perfusion measurement

Background 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. Purpose 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. Material and Methods 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. Results 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, R2 = 0.26 and 0.46, P = 0.001, R2 = 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. Conclusion 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.

Ultrasonographic evaluation of the rectus abdominis muscle after breast reconstruction with the DIEP flap

The aim of this study was to evaluate whether the dissection of the vascular pedicle of the deep inferior epigastric perforator (DIEP) flap could induce secondary muscle atrophy. Evaluation of the rectus abdominis muscle was performed using ultrasonography, and the muscle thickness was measured as an expression of muscle substance. This was performed at 4 levels: below the xiphoid process, at the umbilicus level, above the symphysis, and between the 2 last mentioned (central zone). The results were expressed as the ratio of the muscle thickness on the operated side where dissection of the vascular pedicle was performed to the thickness of the contralateral not operated muscle. Thirteen patients were included with a mean follow up of 20 months (range, 7–42months). The combined measurements showed that the thickness of the muscle as a whole was significantly reduced on the operated side compared with the opposite side. Broken down to the specific levels, the greatest reduction in thickness, approximately 10%, was found at the xiphoid process and above the symphysis. We conclude that performing the dissection of the vascular pedicle of the DIEP flap gives a small but significant degree of muscular atrophy.

Prophylactic peritoneal fenestration to prevent morbidity after kidney transplantation: a randomized study.

Background. 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. Methods. 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. Results. 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). Conclusion. 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.

The Feasibility of Contrast-Enhanced Ultrasound During Uterine Artery Embolization: A Pilot Study

PurposeTo evaluate the feasibility of using contrast-enhanced ultrasound (CEUS) during uterine artery embolization (UAE) in order to define the correct end-point of embolization with complete devascularization of all fibroids.MethodsIn this prospective study of 10 consecutive women undergoing UAE, CEUS was performed in the angiographic suite during embolization. When the angiographic end-point, defined as the “pruned-tree” appearance of the uterine arteries was reached, CEUS was performed while the angiographic catheters to both uterine arteries were kept in place. The decision whether or not to continue the embolization was based on the findings at CEUS. The results of CEUS were compared with those of contrast-enhanced magnetic resonance imaging (MRI) 1 day as well as 3 months following UAE.ResultsCEUS was successfully performed in all women. In 4 cases injection of particles was continued based on the findings at CEUS despite angiographically complete embolization. CEUS imaging at completion of UAE correlated well with the findings at MRI.ConclusionThe use of CEUS during UAE is feasible and may increase the quality of UAE.

Spontaneous regression of initially elevated peak systolic velocity in renal transplant artery

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.