Severe acute pancreatitis requiring drainage therapy: findings on computed tomography as predictor of patient outcome.

BACKGROUND/AIMS: To evaluate whether morphologic features on computed tomography (CT) correlate with outcome of patients with severe acute pancreatitis (SAP). METHODS: 80 patients with SAP requiring percutaneous drainage therapy were retrospectively analyzed. Twelve CT features beyond the CT severity index (CTSI) were studied. Endpoints for patient outcome were patient death, length of hospital and ICU stay. The twelve features and the CTSI score were correlated with mortality using Kaplan-Meier estimator and correlated with length of hospital and ICU stay using the χ(2) test. A p value ≤0.05 was considered statistically significant. RESULTS: Two CT features exhibited a significant correlation with mortality: (1) the number of parts of pancreas (head, corpus, tail) that exhibited areas of necrosis and (2) the presence of distant fluid collections (posterior pararenal space and/or paracolic gutter). Mortality was 42% (21 of 50 patients) and 20% (6 of 30 patients) if two/all three parts or none/one part of the pancreas exhibited necrosis, respectively. Mortality was 46% (18 of 39 patients) and 22% (9 of 41 patients) if distant fluid collections were present or absent, respectively. All other imaging features including the CTSI showed no significant correlation with patient outcome. CONCLUSION: We identified two morphologic features on CT that might be helpful to predict prognosis of patients suffering from SAP. and IAP.

Primary percutaneous aspiration and thrombolysis for the treatment of acute embolic superior mesenteric artery occlusion.

OBJECTIVES: To evaluate technical success rate and clinical outcome of patients with acute embolic superior mesenteric artery (SMA) occlusion who were treated with primary percutaneous revascularization. METHODS: At three medical centers the radiological information system databases were used to identify all patients in whom primary percutaneous revascularization for the treatment of acute embolic SMA occlusion was attempted between 2001 and 2010. Percutaneous treatment was performed in 15 patients (median age 80 years, range 49-88 years). These patients represent the study population. Eleven patients reported abdominal pain. Five patients exhibited peritoneal signs. Revascularization was defined as complete technical success if (1) patency of the SMA with residual stenosis of not more than 30% in diameter and (2) sufficient perfusion of the entire bowel were obtained. RESULTS: Complete technical success was achieved in eleven patients. After percutaneous revascularization laparotomy was performed in six patients and in three of them bowel resection was carried out (length of resected segments 20-80 cm). The 30-day mortality was 33% (five of 15 patients). None of the surviving patients exhibited short-bowel syndrome. CONCLUSIONS: Primary percutaneous aspiration and thrombolysis constitutes a promising alternative to surgical revascularization in selected patients with acute embolic SMA occlusion.

MRI enterography: the future of small bowel diagnostics?

MRI plays an increasing role in small bowel imaging of Crohn's disease. MR enterography (MRE) without nasojejunal intubation and radiation exposure offers similar results compared to MR enteroclysis (with intubation) and should be therefore the preferred method. Sensitivity and specificity is comparable to that of CT enterography. Capsule endoscopy is obviously superior to MRE in detecting superficial lesions, but this is limited to the mucosa and stenosis has to be excluded before examination using imaging, like MRE. There are no convincing studies in the literature regarding assessment of disease activity with imaging. Moreover, there is no consensus in the literature about a suitable reference standard.

Sono-hepatic-arteriography (Sono-HA) in the assessment of hepatocellular carcinoma in patients undergoing transcatheter arterial chemoembolization (TACE).

PURPOSE: The aim of our study was to evaluate sono-hepatic-arteriography in patients with hepatocellular carcinoma undergoing transcatheter arterial chemoembolization. MATERIALS AND METHODS: We evaluated 15 patients with hepatocellular carcinoma undergoing TACE who presented in our institution from February 2006 to May 2008. All patients underwent a conventional B-mode ultrasound examination using a high-end machine and a multi-frequency transducer (2.5 - 4 MHz) before dynamic contrast-enhanced ultrasound examination was carried out. For the sono-hepatic-arteriography 1 ml SonoVue was injected as a bolus using the formerly placed intraarterial catheter. Biphasic enhanced computed tomography was performed using a 16-slice CT scanner up to 48 hours before transcatheter arterial chemoembolization and during follow-up. RESULTS: The lesion size (of the largest lesion) ranged from 1 to 13 centimeters in their largest diameter (mean: 4.8 cm). Contrast-enhanced ultrasound diagnosed more lesions than B-mode sonography in eight cases and more lesions than computed tomography in 5 patients. The findings of sono-hepatic-arteriography were correct in fourteen cases (93.3 %). Direct impact on patient management was seen in eleven patients (73.3 %). CONCLUSION: We were able to show that the application of an intraarterial sonographic contrast agent during embolization is able to diagnose new lesions on the one hand and to assess the embolization success on the other. This might improve transcatheter arterial chemoembolization results and patient outcome.

Detection and characterization of endoleaks following endovascular treatment of abdominal aortic aneurysms using contrast harmonic imaging (CHI) with quantitative perfusion analysis (TIC) compared to CT angiography (CTA).

PURPOSE: To show the feasibility of the detection of endoleaks following endovascular treatment of aortic aneurysms using contrast harmonic imaging (CHI) in comparison to computed tomography angiography (CTA). MATERIALS AND METHODS: 51 patients with suspected endoleaks, who underwent previous endovascular treatment for abdominal aortic aneurysm, were examined using CTA and vascular ultrasound. Biphasic CTA in all cases and digital subtraction angiography (DSA) in 8 patients were evaluated by two radiologists in consensus and served as the standard of reference. Ultrasound was performed by an experienced examiner with a multi-frequency linear transducer (2 - 4 MHz) using CHI following bolus injection of 2.4 ml of SonoVue® IV (maximum 5 ml). All images were evaluated by two observers in consensus regarding the reperfusion of the abdominal aneurysm using time intensity curve (TIC) analysis. RESULTS: In 30 of 51 patients, endoleaks were detected concordantly in CHI and CTA. In 20 of 51 patients, no endoleak was found in CHI and CTA/DSA. In one patient, a type II endoleak could initially only be detected in CHI and was later confirmed in follow-up examinations by CTA (sens. 99%, spec. 93%, NPV 99 %, PPV 95%). TIC analysis allowed evaluation of the perfusion dynamics of endoleaks in all patients. Significant differences were found (p < 0.05, Mann Whitney U Test) regarding the perfusion within the aneurysm when an endoleak was present (10.39 ± 4.29 dB) or not present (6.42 ± 2.86 dB). CONCLUSION: CHI with perfusion analysis allows definite detection of endoleaks, especially if contraindications for CTA are present. CHI presents an alternative for follow-up monitoring.

[PACS: acceptance by orthopedic surgeons]. / PACS: Akzeptanz bei Orthopäden und Unfallchirurgen.

PURPOSE: The goal of the study was to evaluate the acceptance of a web-based picture archiving and communication system (PACS) by orthopedic surgeons 1 year after implementation. MATERIALS AND METHODS: One year after the implementation of a web-based PACS all physicians were surveyed with a standardized questionnaire. Questions included: speed of PACS, quality of clinicoradiological meetings, quality of monitors, PACS training, and performance. Data were evaluated separately for the Department of Orthopedic Surgery and the reference group of all other physicians. RESULTS: Among the respondents, 92% of the orthopedic surgeons stated there was a reduction of time required to receive images, and 64% concluded that patient care was faster. Archived images were received in less than 5 min in 82% after PACS and in 8% before PACS. The clinicoradiological meetings improved with PACS in 100% due to beamer presentation. All would recommend a PACS. The equipment to view images in the operating theater was assessed as being good or very good by 83%; monitor quality was judged better for the outpatient clinics (100% good or very good). Conventional radiograms were missed at the ward rounds by 56%. Training for PACS was considered sufficient by 67%, and 15% asked for refresher courses. In the reference group 60% asked for refresher courses. In the comparison of orthopedic surgeons with the reference group PACS was judged better especially concerning the viewing software and quality of monitors. CONCLUSION: There is an over all acceptance of PACS by physicians outside the radiology department. The availability of images was not only facilitated it was faster as well. However, the quality of monitors in the operating theater should be improved. To achieve sustained success of PACS consistent training on PACS and its features is necessary. Conventional radiograms were often missed at the ward rounds.

Evaluation of malignant liver tumors: biphasic MS-CT versus quantitative contrast harmonic imaging ultrasound.

PURPOSE: It was the aim of our study to establish the extent to which contrast enhancement with SonoVue(R) in combination with quantitative evaluation of contrast-medium dynamics facilitates the detection of malignant hepatic tumors. MATERIALS AND METHODS: One hundred patients with histologically confirmed malignant or benign hepatic tumors (maximum size 5 cm) were analyzed. We used a high-end ultrasound machine (Logic 9, GE Healthcare, Milwaukee, WI, USA), with a multifrequency curved array transducer (2.5 - 4 MHz), Contrast-enhanced ultrasound (bolus injection 2.4 mL SonoVue(R)) was carried out with the intermittent breath-holding technique. Native vascularization was analyzed with power Doppler sonography. The contrast-enhanced dynamic ultrasound investigation was carried out with contrast harmonic imaging in the true detection mode during the arterial, portal venous and late phases. The mechanical index was set at 0.15. Perfusion analysis was performed by post-processing of the raw data (time intensity curve [TIC] analysis). Biphasic 16- or 64-slice multislice computed tomography served as reference method in nearly all cases. RESULTS: One hundred patients with 59 malignant (43 colon, 5 breast, 2 endocrine metastases, 7 hepatocellular carcinomas and 2 kidney cancers) and 41 benign (12 circumscribed fatty changes, 2 abscesses, 7 focal nodular hyperplasias, 5 complicated cysts and 15 hemangiomas) tumors were included. The CT classification was true positive in 71 of 92 patients, false negative in 8 cases, and in 13 cases no final diagnosis was possible; sensitivity was 96.7 % and specificity was 71.4 % for CT. The quantitative contrast harmonic imaging ultrasound classification was true positive in 98 of 100 patients and false negative in 2 cases; the sensitivity was 98.6 % and the specificity was 96.6 %. The Fisher test showed a significant difference at p < 0.05. No investigator-dependency was noted. CONCLUSION: In our study contrast-enhanced ultrasound was more accurate than multislice computed tomography in the prediction of malignancy and benignity of liver tumors.

Pre-surgical evaluation of ICA-stenosis using 3D power Doppler, 3D color coded Doppler sonography, 3D B-flow and contrast enhanced B-flow in correlation to CTA/MRA: first clinical results.

AIM: Pre-surgical evaluation of the extent of internal carotid artery stenosis (ICA) according to NASCT criteria using digital 3D ultrasound methods. MATERIAL/METHODS: In a prospective study, 25 patients (54-88 years, mean 75) with neurological deficits and the diagnosis of ICA stenosis underwent pre-surgical ultrasound examination using Color Coded Duplex Sonography (CCDS), 3D CCDS, 3D power Doppler, 3D B-flow, contrast enhanced 3D B-flow, and CTA/MRA. Ultrasound was performed by an experienced examiner with a multifrequency linear transducer (6-9 MHz, Logiq 9, GE). After bolus injection of 2.4 ml Sonovue i.v., low mechanical index technique (MI<0.16) was used for contrast enhanced 3D B-flow. As reference method for evaluation of the extent of ICA stenosis each patient underwent CTA (multislice CT, Sensation 16, Siemens) and/or MRA (1.5 T, Symphony Siemens). Indications for surgery (carotid EEA) followed the NASCET criteria. All images were interpreted and evaluated independently by two observers with three measurements of the degree of the ICA stenosis. For assessment of the extent of stenosis a 10%-scale from 50% to 99% was used. Statistical analysis was performed using Spearman Correlation and Wilcoxon Signed Rank Test with a significance threshold of p<0.05. RESULTS: Assessment of the extent of ICA stenosis during surgery and in CTA/MRA displayed a range from 60% to 99% (mean 80%). Non significant differences were found with paired Wilcoxon test only for 3D B-flow with and without contrast medium (p<0.05). Correlation with surgical evaluation regarding the extent of ICA stenosis using Spearman correlation teat was 0.77 for B-scan, 0.90 for 3D CCDS, 0.84 for 3D Power Doppler, 0.91 for B-flow and 0.93 for contrast enhanced 3D B-flow. When circular calcifications were present, contrast enhanced flow detection of 3D B-flow proved to be useful. Visualisation of intrastenotic variances of severe and profound stenosis (70-99%) without blooming and reverberation artefacts was possible only with 3D B-flow. This facilitates the detection of the morphology of plaques ulcers as an embolic source. CONCLUSION: In correlation with surgery and CTA/MRA, a valid evaluation of the extent and morphology of ICA stenosis using 3D B-flow, with and without contrast medium, is feasible.

[A 47-year-old patient with longstanding nicotine abuse, increasing dyspnea on exertion and lower and peripheral lung predominant ground-glass opacities]. / 47-jähriger Patient mit langjährigem Nikotinabusus, zunehmender Belastungsdyspnoe und diffusen, peripher und basal betonten Milchglastrübungen in der Lunge.

The causal relationship between cigarette smoking and a number of interstitial lung diseases continues to evolve. These "smoking-related interstitial lung diseases" (SR-ILD) are a heterogeneous group of entities which have overlapping imaging findings and which can coexist. The presented case of a patient with smoking history and pulmonary ground-glass opacities demonstrates that thorough knowledge of the various manifestations of SR-ILD is essential for a confident diagnosis.

[A 74-year-old female patient with histologically proven carcinoid of the lungs and pulmonary mosaic pattern]. / 74-jährige Patientin mit histologisch gesichertem Karzinoid der Lunge und pulmonalem Mosaikmuster.

Diffuse idiopathic neuroendocrine cell hyperplasia (DIPNECH) can be idiopathic or reactive to chronic airway disease, then termed pulmonary neuroendocrine cell hyperplasia (PNECH). DIPNECH can be complicated by obliterative bronchiolitis and is presumably often misdiagnosed because the clinical symptoms are unspecific, the entity is relatively unknown and high-resolution computed tomography (HRCT) in inspiration and expiration is necessary for the diagnosis. However, the HRCT findings of air-trapping in combination with nodules are very characteristic and should raise suspicion of this entity. DIPNECH is thought to be a precursor of tumorlets and carcinoids and usually runs a benign course. The diagnosis is confirmed by histology.

[Diagnosis of and therapy for gastric cancer--work-flow]. / Diagnostik und Therapie des Magenkarzinoms--Workflow.

AIM: This review comments on the diagnosis and treatment of gastric cancer in the classical meaning--excluding adenocarcinoma of the -oesophagogastric junction. Algorithms of diagnosis and care with respect to tumour stage are presented. PREOPERATIVE DIAGNOSIS: Besides oesophagogastroduodenoscopy, endoscopic ultrasonography is necessary for the accurate diagnosis of T categories and as a selection criterion for neoadjuvant chemotherapy. Computed tomography is recommended for preoperative evaluation of tumours > T1, laparoscopy has become an effective stag-ing tool in T3 and T4 tumours avoiding unnecessary laparotomies and improving the detection of small -liver and peritoneal metastases. TREATMENT: Endoscopic mucosal resection and submucosal dissection are indicated in superficial cancer confined to the mucosa with special characteristics (T1 a / no ulcer / G1, 2 / Laurén intestinal / L0 / V0 / tumour size < 2 cm). In all other cases total gastrectomy or distal subtotal gastric resection are indicated, the latter in cases of tumours located in the distal two-thirds of the stomach. Standard lymphadenectomy (LAD) is the D2 LAD without distal pancreatectomy and splenectomy. The Roux-en-Y oesophagojejunostomy is still the preferred type of reconstruction. An additional pouch reconstruction should be considered in -patients with favourable prognosis, this also -applies for the preservation of the duodenal passage by jejunum interposition. Extended organ resections are only indicated in cases where a R0-resection is possible. Hepatic resection for metachronous or synchronous liver metastases is rarely advised since 50 % of patients with liver metastases show concomitant peritoneal dissemination of the disease. DISCUSSION AND CONCLUSIONS: Undergoing gastrectomy at a high-volume centre is associated with lower in-hospital mortality and a better prognosis, however, clear thresholds for case load cannot be given. Perioperative chemotherapy and postoperative chemoradiotherapy are based on the MAGIC and MacDonald trials. Perioperative chemotherapy should be performed in patients with T3 and T4 tumours with the aim to increase the likelihood of curative R0-resection by downsizing the tumour. Adjuvant postoperative chemotherapy cannot be recommended since its benefit has so far not been proven in randomised trials. In selected patients with incomplete lymph-node dissection and questionable R0-resection postoperative chemoradiotherapy may be debated.

Outcome of patients with acute, necrotizing pancreatitis requiring drainage-does drainage size matter?

AIM: To assess the outcome of patients with acute necrotizing pancreatitis treated by percutaneous drainage with special focus on the influence of drainage size and number. METHODS: We performed a retrospective analysis of 80 patients with acute pancreatitis requiring percutaneous drainage therapy for infected necroses. Endpoints were mortality and length of hospital stay. The influence of drainage characteristics such as the median drainage size, the largest drainage size per patient and the total drainage plane per patient on patient outcome was evaluated. RESULTS: Total hospital survival was 66%. Thirty-four patients out of all 80 patients (43%) survived acute necrotizing pancreatitis with percutaneous drainage therapy only. Eighteen patients out of all 80 patients needed additional percutaneous necrosectomy (23%). Ten out of these patients required surgical necrosectomy in addition, 6 patients received open necrosectomy without prior percutaneous necrosectomy. Elective surgery was performed in 3 patients receiving cholecystectomy and one patient receiving resection of the parathyroid gland. The number of drainages ranged from one to fourteen per patient. The drainage diameter ranged from 8 French catheters to 24 French catheters. The median drainage size as well as the largest drainage size used per patient and the total drainage area used per patient did not show statistically significant influence on mortality. CONCLUSION: Percutaneous drainage therapy is an effective tool for treatment of necrotizing pancreatitis. Large bore drainages did not prove to be more effective in controlling the septic focus.

Mesenteric ischemia--outcome after surgical therapy in 83 patients.

BACKGROUND: Intestinal ischemia is the prime vascular emergency for the visceral surgeon. However, the diagnosis of mesenteric ischemia is difficult, the surgical options are often limited and the overall outcome is generally poor. METHODS: We report on a single center series of 83 patients undergoing surgery for mesenteric ischemia during a 3-year period. Risk factors, clinical presentation, type and timing of imaging studies and their implications for surgical therapy and outcome are analyzed. RESULTS: Hypertension and diabetes were the most common risk factors (68/64% of all patients). Abdominal pain was the most general symptom upon presentation to the surgical unit (73%). Two-phase, contrast-enhanced computed tomography was applied as the standard preoperative imaging modality (correct diagnosis in 69%). Bowel resections were necessary in most patients; approaches to restore blood flow by vascular surgery interventions were applied in 17 patients (20%). The overall morbidity and mortality rate in our study cohort was expectedly high (59% 1 month mortality). CONCLUSION: The diagnosis and surgical treatment of mesenteric ischemia remains a major difficulty. We recommend preoperative CT analysis followed by an aggressive indication for early surgical exploration and bowel resection. An attempt of revascularization is justified for selected patients with limited macrovascular disease.

[Stenting in the treatment of chronic mesenteric ischemia: technical and clinical success rates]. / Chronische mesenteriale Ischämie: Technische und klinische Erfolgsrate der perkutanen Stentangioplastie.

PURPOSE: To evaluate the technical and clinical success rates of percutaneous stent revascularization in the treatment of chronic mesenteric ischemia (CMI). PATIENTS AND METHODS: 17 patients (12 female) with typical symptoms of CMI were treated by percutaneous stent placement for stenoses of the splanchnic arteries (celiac trunk; superior mesenteric artery, SMA; inferior mesenteric artery, IMA). The primary and secondary technical success, primary and secondary clinical success, and the long-term clinical outcome were determined. RESULTS: A total of 24 stents were implanted in 21 splanchnic arteries (12 stents in the celiac trunk, 11 in the SMA and 1 in the IMA). The primary technical success rate was 91% (19/21 arteries), the secondary technical success rate was 95% (21/22 arteries). Clinical follow-up was available for 16 patients. The primary clinical success rate was 81% (13/16 patients). Following two secondary interventions, the secondary clinical success rate was 94% (15/16 patients). Long-term clinical success was achieved in 15 of 16 patients (94%) with a mean follow-up of 26 months. One patient died within 30 days of the intervention and two patients demonstrated major complications (1 dissection, 1 stent dislocation). None of the patients required surgical revascularization and none of the patients died due to recurrent mesenteric ischemia. CONCLUSION: Percutaneous stent placement for the treatment of CMI can be performed with a high technical and clinical success rate as well as an excellent long-term clinical outcome.

[Non-trauma-associated additional findings in whole-body CT examinations in patients with multiple trauma]. / Nicht traumaassozierte Nebenbefunde bei Ganzkörpercomputertomografien im Rahmen der Polytraumadiagnostik.

PURPOSE: Whole-body CT scans for patients with multiple trauma represent an increasingly accepted first diagnostic tool. The multidetector approach in particular provides appropriate diagnostic algorithms for detecting nearly all relevant traumatic findings in a short time with a high grade of sensitivity and specificity. Non-trauma-associated additional findings are commonly depicted based on these CT examinations. The aim of this study is to evaluate the number and quality of these additional findings in consecutive patients with multiple trauma. MATERIALS AND METHODS: Between 3 / 04 and 8 / 06 we scanned 304 patients according to our dedicated multiple trauma protocol. The examination protocol includes a head scan without intravenous contrast followed by a whole-body scan including the neck, thorax and abdomen acquired by a 16-row CT Scanner (Siemens, Sensation 16). The CT scans were retrospectively analyzed by two radiologists with respect to non-trauma-associated findings. Lesions were assessed according to their clinical relevance (highly relevant, moderately relevant, not relevant). For patients with highly relevant findings, additional follow-up research was performed. RESULTS: The average age was 43 years (range 3 - 92). 236 of the patients were male (77.6 %), 68 female (22.4 %). 153 patients (50.3 %) had additional non-trauma-associated findings. In 20 cases (6.6 %) lesions with high clinical relevance were detected (e. g. carcinoma of the kidney or the ovary). In 71 patients (23.4 %) findings with moderate relevance were described. In 63 patients (20.7 %) additional findings without major relevance were diagnosed. CONCLUSION: Whole-body CT scans of patients randomized by a trauma show a considerable number of non-trauma-associated additional findings. In about 30 % of cases, these findings are clinically relevant because further diagnostic workup or treatment in the short or medium-term is needed. The results of these analyses emphasize the diagnostic value of CT examinations with high demands on the examining radiologist.

Evaluation of the vascular integrity of free flaps based on microcirculation imaging techniques.

BACKGROUND: A free-flap graft refers to the free transfer of tissue to cover tissue defects caused by trauma or malperfusion in plastic surgery. The basic principle, which makes a free flap working is an adequate blood flow. We applied new techniques which are able to detect the blood flow of the anastomosis and of dermal and subdermal tissue layers in a reliable way. METHODS: To this end we applied innovative Ultrasound-techniques (contrast enhanced high resolution Ultrasound (US), color coded Doppler sonography (CCDS), Cross Beamtrade mark, Power Doppler, Tissue Harmonic Imagingtrade mark (THI), Speckle Reduction Imagingtrade mark (SRI)), as well as the Indocyanine Green (ICG) fluorescence angiography to evaluate the vascular integrity of 15 parascapular flaps implanted to the fore foot over a period of four years. The age of the subjects ranged from 16 to 60 years. The US machine (GE Logiq 9) was equipped with a Logiq 9L transducer (6-9 MHz) and the modalities of CHI (Contrast Harmonic Imaging) and True Agent Detection (dual view of B-Mode and contrast mode). RESULTS: The borders of the investigated flaps could be best detected using Cross Beamtrade mark Technology with SRItrade mark and THItrade mark. Power Doppler was able to detect anastomotic vessels even if they were twisted or elongated. Reduced perfusion curves were seen in cases with low anastomotic flow in CCDS. The CHItrade mark allowed dynamic flow detection of the microcirculation of the tissue graft over a depth of up to 3 cm including quantitative perfusion curves of tissue microcirculation by using TICtrade mark analysis. There is a strong correlation between the perfusion indices measured by ICG fluorescence angiography and CHItrade mark. Furthermore the ICG showed a remarkable enhancement of fluorescence in the flap borders, which need to be explored in future investigations. CONCLUSION: These new applications provide useful and effective methods for improved postoperative monitoring of free flaps in plastic surgery and can lead to substantial reduction in the overall risk of flap failure.

Intraarterial gadolinium-enhanced magnetic resonance angiography of the renal arteries in humans: feasibility, contrast agent reduction, and accuracy for detection of stenoses.

OBJECTIVE: Feasibility of intraarterial MR angiography of the renal arteries and comparison of the accuracy of intraarterial MR angiography with selective intraarterial digital subtraction angiography (DSA) for detection of stenoses. MATERIALS AND METHODS: Ten consecutive patients (mean, 68 years) with suspected renal artery stenosis underwent a digital subtraction angiography and an intraarterial gadolinium-enhanced MR angiography, performed on a 1.5-T system. For intraarterial MR angiography 60 ml diluted contrast agent (10 ml gadodiamide in 50 ml 0.9% saline solution) was injected through a conventional angiography catheter placed in the suprarenal abdominal aorta using a flow rate of 3.5 ml/s. A three-dimensional (3D) gradient-echo sequence was performed. Differences in the quantitative measurement of stenoses of lesions between DSA and intraarterial MR angiography were evaluated by three observers. Overall impression of the intraarterial MR angiography was documented on a four-point scale (1 = excellent to 4 = poor). Interobserver variability was calculated. RESULTS: Intraarterial MR angiography of the renal arteries was feasible in all patients (100%) with a mean overall impression of all images of 1.8 (SD: 0.71). One of 9 accessory renal arteries was not visualized with intraarterial MR angiography. The overall sensitivity/specificity for detection of significant stenoses (>or=50% stenosis) were 83%/87%. Interobserver variability of intraarterial MR angiography ranged between fair and substantial (0.359-0.622). CONCLUSION: Intraarterial MR angiography of the renal arteries in humans is feasible and has an acceptable sensitivity in detecting stenoses using injections of diluted contrast agent at concentrations as low as 17%.

Contrast harmonic ultrasound and indocyanine-green fluorescence video angiography for evaluation of dermal and subdermal microcirculation in free parascapular flaps.

PURPOSE: Contrast harmonic ultrasound (CHI) with a linear transducer is a new diagnostic approach that allows dynamic and quantitative flow detection of tissue perfusion in microsurgery. The aim of the study was the evaluation of perfusion of the dermal and subdermal layers of microvascular tissue transplants with CHI in comparison to ICG-fluorescence angiography. MATERIAL AND METHOD: In a prospective clinical study Indocyanine-Green Fluorescence Video Angiography and Contrast Enhanced High Resolution Ultrasound (5-10 MHz; linear transducer; Logiq 9; GE) were used for evaluation of the microcirculation in 10 transplanted free parascapular flaps. Two regions were analysed, the centre of the flap and the region of the anastomosis. The perfusion patterns of both methods were compared. RESULTS: The perfusion indexes measured by ICG-fluorescence angiography correlated very precisely in all patients with the quantitative perfusion curves of contrast-enhanced US with CHI. Two flaps with slow filling and low dye intensity showed low contrast enhancement in CHI with modified perfusion curves with slow increase. In two cases a reduced perfusion and filling were found. There were no statistical differences between the two diagnostic methods (p>0.01). CONCLUSION: CHI improves US detections of dermal and subdermal microcirculation in comparison to ICG fluorescence angiography. CHI is a new diagnostic method for postoperative monitoring of free flaps.

Contrast harmonic ultrasound and indocyanine-green fluorescence video angiography for evaluation of dermal and subdermal microcirculation in free parascapular flaps.

PURPOSE: Contrast harmonic ultrasound (CHI) with a linear transducer is a new diagnostic approach that allows dynamic and quantitative flow detection of tissue perfusion in microsurgery. The aim of the study was the evaluation of perfusion of the dermal and subdermal layers of microvascular tissue transplants with CHI in comparison to ICG-fluorescence angiography. MATERIAL AND METHOD: In a prospective clinical study indocyanine-green fluorescence video angiography and contrast enhanced high resolution ultrasound (5-10 MHz; linear transducer; Logiq 9; GE) were used for evaluation of the microcirculation in 10 transplanted free parascapular flaps. Two regions were analysed, the centre of the flap and the region of the anastomosis. The perfusion patterns of both methods were compared. RESULTS: The perfusion indexes measured by ICG-fluorescence angiography correlated very precisely in all patients with the quantitative perfusion curves of contrast-enhanced US with CHI. Two flaps with slow filling and low dye intensity showed low contrast enhancement in CHI with modified perfusion curves with slow increase. In two cases a reduced perfusion and filling were found. There were no statistical differences between the two diagnostic methods (p>0.01). CONCLUSION: CHI improves US detections of dermal and subdermal microcirculation in comparison to ICG fluorescence angiography. CHI is a new diagnostic method for postoperative monitoring of free flaps.

Microcirculation and perfusion with contrast enhanced ultrasound (CEUS) in Crohn's disease: first results with linear contrast harmonic imaging (CHI).

AIM: To evaluate a newly introduced high resolution linear transducer for vascularization and mural perfusion assessment using contrast harmonic imaging (CHI) with quantitative time intensity curve analysis (TIC) in patients with active Crohn's disease (CD). MATERIAL AND METHODS: We prospectively evaluated 14 consecutive patients (7 women, 7 males, age range 19-42 years, median 28 years) with histologically proven CD having an acute episode of the disease applying contrast enhanced MRI and high resolution ultrasound. For the ultrasound we used a newly introduced high resolution linear multi-frequency transducer (6-9 MHz, Logiq 9, GE). Ultrasound was performed by an experienced radiologist applying color coded Doppler sonography (CCDS), power Doppler (PD) and contrast enhanced CHI using the 'true agent detection mode'. Additionally, 5 healthy volunteers were examined by ultrasound applying CCDS, PD and CHI. After the injection of 2.4 ml ultrasound contrast agent (SonoVue) the dynamic CHI cine sequences were recorded as digital raw data for 60 seconds. Therefore we were able to perform a quantitative perfusion analysis using TIC retrospectively. CCDS, PD and CHI with TIC were compared and analyzed. RESULTS: In all 14 patients MRI showed inflammatory changes in the terminal or pre-terminal ileum. Using PD and CCDS enlarged vessels surrounding the bowel wall were visualized in all patients. PD as well as CCDS diagnosed just in 9 of 14 patients augmented mural vessels. Having CHI with TIC increased mural contrast enhancement was diagnosed in all 14 patients. Patients with CD showed a maximum enhancement 36 s after injection with 9 dB (range 5.9-13.2 dB), while healthy volunteers reached the maximum level of 2.8 dB (range 2-3.8 dB) after 23 s (p<0.05). CONCLUSION: Using high resolution linear transducer mural perfusion changes in active Crohn's disease can be appreciated applying CHI with TIC. This technique could be an effective dynamic imaging modality for diagnosis and especially follow-up examination to monitor treatment in CD.