Nationwide Provision of Radiologically-guided Interventional Measures for the Supportive Treatment of Tumor Diseases in Germany - An Analysis of the DeGIR Registry Data. / Flächendeckende Versorgung mit radiologisch-interventionellen supportiven Maßnahmen bei Tumorerkrankungen und anderen Erkrankungen (DeGIR-Modul C) in Deutschland ­ Eine Analyse der DeGIR-Registerdaten.

PURPOSE: In addition to direct oncologic therapy, interventional radiology plays an important supportive role in oncologic therapy primarily guided by other disciplines. These supporting measures include diagnostic punctures, drainages, biliary interventions, central venous access including port implantations, osteoplasties, pain therapies etc.). This study investigated the extent to which these radiologically guided supportive measures are available in Germany. MATERIAL AND METHODS: All interventional procedures documented in the DeGIR-registry (excluding transhepatic portosystemic shunts) of the years 2018 and 2019 were recorded (DeGIR-module C). A breakdown of the documented interventions was performed based on federal states as well as 40 individual regions (administrative districts and former administrative districts). RESULTS: A total of 136,328 procedures were recorded at 216 centers in DeGIR Module C in 2018 and 2019. On average, 389 cases were documented per hospital in 2018 and 394 cases in 2019; the increase per hospital from 2019 is not statistically significant but is relevant in the aggregate when new participating centers are included, with an overall increase of 10 % (6,554 more cases than the previous year). Normalized to one million inhabitants, an average of 781 procedures took place across Germany in 2018 and 860 in 2019. Districts with no registered procedures are not found for Module C.Indications for Module C interventions were mostly interdisciplinary in 2018 and 2019. In this context, the quality of outcome was very high; for the procedures drain placement, marking and biopsy the technical success was 99 %, while the complication rate was lower than 1 %. CONCLUSION: The structural analysis of this work concludes that in Germany there is good nationwide availability of radiologically guided supportive measures in oncological therapy. Accordingly, the training situation for prospective interventional radiologists is good, as the distribution to centers with high experience is excellent. In addition, the overall outcome quality of radiology-guided interventions is very high. KEY POINTS: · In Germany, there is good nationwide coverage of radiologically guided supportive interventions in oncological therapy.. · The training situation for prospective interventional radiologists is good, as the distribution to centers with high experience is excellent.. · The overall outcome quality of radiology-guided interventions is very high.. CITATION FORMAT: · Nadjiri J, Schachtner B, Bücker A et al. Nationwide Provision of Radiologically-guided Interventional Measures for the Supportive Treatment of Tumor Diseases in Germany - An Analysis of the DeGIR Registry Data. Fortschr Röntgenstr 2022; 194: 993 - 1002.

Availability of Interventional Oncology in Germany in the Years 2018 and 2019 - Results from a Nationwide Database (DeGIR Registry Data). / Flächendeckende Versorgung mit radiologisch durchgeführten Verfahren zur interventionell-onkologischen Tumortherapie in Deutschland in den Jahren 2018 und 2019 dargestellt anhand der DeGIR-Registerdaten.

OBJECTIVE: Over the past few decades, radiology has established itself in tumor therapy through interventional oncology including innovative and efficient procedures for minimalinvasive treatment of various tumor entities besides the "classic" therapeutic options such as surgery, chemotherapy and radiotherapy.Aim of this study was to evaluate the extent to which interventional oncology can provide nationwide care using the data from the register of the German Society for Interventional Radiology and Minimally Invasive Therapy (DeGIR registry), which records radiological interventions as part of quality assurance. METHODS: The numbers of interventions of participating clinics, which were recorded as part of module D (oncological procedures including TACE or other tumor-specific embolization, ablation, percutaneous tumor therapy) and identified by the DeGIR registry between 2018 and 2019, were analyzed retrospectively. The collected intervention data were evaluated regarding federal states and 40 smaller regions (administrative districts and former administrative districts). RESULTS: In 2018, 11 653 oncological interventions in 187 clinics were recorded by the DeGIR registry. In 2019, the number of participating clinics rose to 216 and the number of oncological interventions increased by 6 % to 12 323. The average number of oncological interventions per clinic decreased slightly from 62.5 (2018) to 57.1 (2019). The DeGIR requirement for being certified as a training center was met by 116 clinics in 2018 including 31 clinics with more than 100 interventions and 129 clinics in 2019 including 36 with more than 100 interventions. Oncological interventions have been performed in each of the 40 regions. An average of 599 interventions per region (standard deviation of 414) was recorded in the period between 2018 and 2019. CONCLUSION: Based on the distribution of the documented oncological interventions at federal state level as well as the district level, the supply of interventional tumor therapy depends on the geographical location. Therefore, the demand of oncological interventions might not be sufficiently covered in some regions. KEY POINTS: · Interventional-oncological tumor therapies are performed throughout Germany. · Looking at the notable geographical differences, the need for interventional oncological procedures does not seem to be sufficiently met.. · In order to improve the comprehensive provision of oncological interventions, the training of interventional radiologists should be promoted further.. CITATION FORMAT: · Radosa CG, Nadjiri J, Mahnken AH et al. Availability of Interventional Oncology in Germany in the Years 2018 and 2019 - Results from a Nationwide Database (DeGIR Registry Data). Fortschr Röntgenstr 2022; 194: 755 - 761.

Embolization of Hemorrhoidal Arteries: A Novel Endovascular Therapy Option for the Treatment of Hemorrhoidal Disease. / Hämorrhoidenembolisation: Eine neue minimalinvasive endovaskuläre Therapieoption bei Hämorrhoidalleiden.

BACKGROUND: Hemorrhoids are a widespread disease. Treatment options range from dietary measures to open surgery. A novel treatment approach is the embolization of the hemorrhoidal arteries. METHOD: A review was performed based on a selective literature search in PubMed representing the current state of research. The keywords "hemorrhoid" and "embolization" and "emborrhoid" were used. In addition, technical details of the hemorrhoidal embolization procedure are explained. RESULTS AND CONCLUSION: Embolization of hemorrhoidal arteries is a safe treatment, which allows efficient symptom control even in patients with contraindications for open surgery. KEY POINTS: · Embolization of hemorrhoidal arteries is a new approach to the treatment of hemorrhoids.. · Embolization of hemorrhoidal arteries is feasible in patients with contraindications for open surgery such as hypercoaguable states and contraindications for general anesthesia.. · The endovascular approach causes no rectal and anal trauma and associated complications can be avoided.. · The treatment of bleeding hemorrhoids seems to be particularly effective.. · No ischemic complications have been reported so far when coils as well as particles were used.. CITATION FORMAT: · Feyen L, Freyhardt P, Schott P et al. Hämorrhoidenembolisation: Eine neue minimalinvasive endovaskuläre Therapieoption bei Hämorrhoidalleiden. Fortschr Röntgenstr 2022; 194: 266 - 271.

CIRSE Standards of Practice on Percutaneous Transhepatic Cholangiography, Biliary Drainage and Stenting.

This CIRSE Standards of Practice document is aimed at interventional radiologists and provides best practices for performing percutaneous transhepatic cholangiography, biliary drainage and stenting. It has been developed by an expert writing group established by the CIRSE Standards of Practice Committee.

Position Paper of the German Society for Interventional Radiology (DeGIR) on Prostatic Artery Embolization. / Positionspapier der Deutschen Gesellschaft für Interventionsradiologie (DeGIR) zur Prostataarterienembolisation.

BACKGROUND: In recent years prostate artery embolization (PAE) evolved into a clinically established minimally invasive endovascular treatment option for lower urinary tract symptoms caused by benign prostate syndrome (BPS). METHODS: In this interdisciplinary position paper, initiated by the steering group for research of the German Society for Interventional Radiology (IR), the method of PAE is presented and discussed in the context of current evidence. RESULTS: PAE is a safe IR procedure for the treatment of BPS. In terms of symptom relief, measured with the IPSS (International Prostate Symptom Score), the PAE has comparable effect, similar to the historic gold standard, transurethral resection (TUR) of the prostate. With regard to reducing subvesical obstruction PAE is inferior to TUR, but does not limit subsequent surgery. Based on current evidence, PAE is recommended by the British National Institute for Health and Care Excellence as an alternative therapy. The feasibility under local anaesthesia and the preservation of sexual function are important arguments for patients in favour of interventional therapy. Patient selection and therapy concepts require close interdisciplinary collaboration between urologists and radiologists. CONCLUSION: Effectiveness and safety of PAE for the treatment of BPS are proven. Further randomized trials should focus on long term outcome and help to identify most suitable indications for PAE. KEY POINTS: · PAE, an endovascular procedure, is a patient-friendly, minimally invasive, alternative therapy option of the BPS. · PAE can reduce the symptoms of the lower urinary tract (LUTS), comparable to transurethral resection (TUR). The deobstructive and volume-reducing potential of the PAE is inferior to that of the TUR. · The main advantages of PAE are use of local anesthesia (no general anesthesia required), short patient recovery and maintenance of sexual function, including antegrade ejaculation.. · Based on current evidence PAE should be considered after conservative drug therapy and before TUR.. · The role of PAE in the context of other minimally invasive procedures (MIST) requires further evaluation with an open minded approach towards PAE.. · PAE is carried out by interventional radiologists, usually on a referral basis from urologists, and requires close interdisciplinary cooperation.. CITATION FORMAT: · Kovacs A, Bücker A, Grimm M et al. Position Paper of the German Society for Interventional Radiology (DeGIR) on Prostatic Artery Embolization. Fortschr Röntgenstr 2020; 192: 835 - 846.

Radiation Dose in Prostatic Artery Embolization Using Cone-Beam CT and 3D Roadmap Software.

PURPOSE: To evaluate the radiation dose in patients undergoing prostatic artery embolization (PAE) using cone-beam CT and 3-dimensional (3D) guidance software. MATERIALS AND METHODS: In this single-center retrospective study, 100 patients with benign prostatic hyperplasia (mean prostate volume, 83.6 mL ± 44.2; 69.4 ± 9.6 years of age; body mass index, 26.5 ± 4.2) were treated using PAE between October 2016 and April 2018. Informed consent was obtained from all participants included in the study. All patients received at least 1 intraprocedural cone-beam CT per side for evaluation of the vessel anatomy and software rendering of 3D guidance for catheter guidance. Digital subtraction angiography (DSA) was performed in the distal branches only. The total dose area product (DAP), along with the DAP attributed to fluoroscopy, DSA, and cone-beam CT, were assessed. RESULTS: Bilateral embolization was achieved in 83 patients (83%). The average total DAP was 134.4 Gy ⋅ cm2 ± 69.5 (range, 44.7-410.9 Gy ⋅ cm2). Fluoroscopy, DSA, and cone-beam CT accounted for 35.5 Gy ⋅ cm2 ± 21.3 (range, 8.6-148.6 Gy ⋅ cm2) or 26.4% (percentage of total DAP), 58.2 Gy ⋅ cm2 ± 48.3 (range, 10.3-309.3 Gy ⋅ cm2) or 43.3%, and 40.7 Gy ⋅ cm2 ± 14.5 (range, 15.9-86.3 Gy ⋅ cm2) or 30.3%, respectively. Average procedure time was 89.4 ± 27.0 minutes, and the average fluoroscopy time was 30.9 ± 12.2 minutes. CONCLUSIONS: Intraprocedural cone-beam CT in combination with 3D guidance software allows for identification and catheterization of the prostatic artery in PAE. Furthermore, the results of this trial indicate that this study protocol may lead to a low overall radiation dose.

Presepsin and Inflammatory Markers Correlate With Occurrence and Severity of Nonocclusive Mesenteric Ischemia After Cardiovascular Surgery.

OBJECTIVES: To prospectively evaluate the relationship of established inflammatory markers and presepsin on nonocclusive mesenteric ischemia and to correlate presepsin levels to the occurrence and severity of nonocclusive mesenteric ischemia. DESIGN: Patients were prospectively enrolled and blood samples taken, followed by a retrospective evaluation of laboratory values and angiographic findings. The study was ethics committee approved. SETTINGS: Patients with clinical suspicion of nonocclusive mesenteric ischemia underwent catheter angiography of the superior mesenteric artery. Images were assessed by two experienced radiologists on consensus basis using a previously published standardized reporting system (Homburg-Nonocclusive Mesenteric Ischemia-Score). Two groups were formed according to the severity of nonocclusive mesenteric ischemia, mild and severe, patients without clinical signs of nonocclusive mesenteric ischemia formed the reference group. These data were correlated to inflammatory blood markers assessed pre- and postoperatively: C-reactive protein, leucocytes, procalcitonin, and presepsin as well as outcome data. PATIENTS: Between January 2010 and March 2011, a total of 839 patients undergoing cardiovascular surgery participated in this study. MEASUREMENTS AND MAIN RESULTS: Mild nonocclusive mesenteric ischemia was diagnosed in 4.5%, and severe nonocclusive mesenteric ischemia in 3.2%. Median postoperative presepsin concentrations were significantly greater in mild and severe nonocclusive mesenteric ischemia than in non-nonocclusive mesenteric ischemia. Statistics showed that postoperative presepsin better discriminated mild and severe nonocclusive mesenteric ischemia than any other tested biomarker. CONCLUSIONS: Elevated postoperative plasma presepsin concentrations are an independent predictor of mild and severe nonocclusive mesenteric ischemia. The established inflammatory blood markers significantly correlate with the development and severity of nonocclusive mesenteric ischemia.

Occurrence and severity of non-occlusive mesenteric ischemia (NOMI) after cardiovascular surgery correlate with preoperatively assessed FGF-23 levels.

PURPOSE: To evaluate the value of preoperatively assessed fibroblast growth factor 23 (FGF-23) levels and to correlate FGF-23 with angiographic findings in non-occlusive mesenteric (NOMI) ischemia using a standardized scoring system. MATERIALS AND METHODS: Between 2/2011 and 3/2012 a total of 865 patients (median age: 67 years) underwent cardiovascular surgery during this ethics committee approved, prospective study. 65 of these patients had clinical suspicion of NOMI and consequently underwent catheter angiography of the superior mesenteric artery. Images were assessed using a standardized reporting system (Homburg-NOMI-Score). These data were correlated to following preoperative parameters of kidney function: cystatin C, creatinine, FGF-23 and estimated glomerular filtration rate (eGFR), and outcome data (death, acute renal failure) using linear and logistic regressions, as well as nonparametric tests. RESULTS: Significant correlations were found between FGF-23 and the angiographic appearance of NOMI (p = 0.03). Linear regression analysis showed no significant correlation to the severity of NOMI with creatinine (p = 0.273), cystatin C (p = 0.484), cystatin C eGFR (p = 0.914) and creatinine eGFR (p = 0.380). Logistic regression revealed a significant correlation between death and the Homburg-NOMI-Score (p<0.001), but not between development of NOMI and acute renal failure (p = 0.122). The ROC Analysis yielded an area under the curve of 0.695 (95% CI: 0.627-0.763) with a sensitivity of 0.672 and specificity of 0.658. CONCLUSIONS: FGF-23 significantly correlates with the severity of NOMI, which is in contrast to other renal function parameters. The applied scoring system allows to predict mortality in NOMI patients.

A scoring-system for angiographic findings in nonocclusive mesenteric ischemia (NOMI): correlation with clinical risk factors and its predictive value.

PURPOSE: This study was designed to evaluate the clinical value of a standardized angiographic scoring system in patients with nonocclusive mesenteric ischemia (NOMI). METHODS: Sixty-three consecutive patients (mean age: 73 ± 8 years) with suspect of NOMI after cardiac or major thoracic vessel surgery underwent catheter angiography of the superior mesenteric artery. Images were assessed by two experienced radiologists on consensus basis using a scoring system consisting of five categories, namely vessel morphology, reflux of contrast medium into the aorta, contrasting and distension of the intestine, as well as the time to portal vein filling. These were correlated to previously published risk factors of NOMI and outcome data. RESULTS: The most significant correlation was found between the vessel morphology and death (p < 0.001) as well as reflux of contrast medium into the aorta and death (p = 0.005). Significant correlation was found between delayed portal vein filling and preoperative statin administration (p = 0.011), previous stroke (p = 0.033), and renal insufficiency (p = 0.043). Reflux of contrast medium correlated significantly with serum lactate >10 mmol/L (p = 0.046). The overall angiographic score correlated with death (p = 0.017) and renal insufficiency (p = 0.02). The ROC-analysis revealed that a score of ≥3.5 allows for identifying patients with increased perioperative mortality with a sensitivity of 85.7 % and a specificity of 49 %. With the use of a simplified score (vessel morphology, reflux of contrast medium into the aorta, and time to portal vein filling), specificity was increased to 71.4 %. CONCLUSIONS: The applied scoring system allows standardized interpretation of angiographic findings in NOMI patients. Beyond that the score seems to correlate well with risk factors of NOMI and outcome.

Liver fibrosis: how many samples in transjugular liver biopsy are sufficient? Histological vs. clinical value.

PURPOSE: Liver biopsy (LB) is a diagnostic procedure to obtain histological diagnosis, grading and staging in individuals with liver diseases. Most commonly LB is performed percutaneously. However, transjugular liver biopsy (TJLB) is considered as an alternative. The aim of this prospective study was to evaluate the diagnostic accuracy of TJLB. METHODS: TJLB with a semi-automatic Tru-Cut System (18G) was performed in 39 patients with various liver diseases (21 females and 18 males; age range 11-77 years). The number of complete portal tracts (CPTs), lengths and numbers of acquired cores, number of performed cutting steps (passes), and the possibility to obtain histological diagnosis were analyzed. RESULTS: There were no procedure-related complications, and in total 45 procedures were performed. Diagnosis could be established in 88.8 % of all samples, in five cases histology yielded no diagnosis due to an inadequate number of CPTs or sample fragmentation. In average, 4 passes were performed and 4 (range 1-7) cores were obtained. Median core length was 1.1 cm (range 0.4-1.9 cm), median number of CPTs was 7 (range 0-20). Liver fibrosis in general led to a decreased number of CPTs (p < 0.05). CONCLUSIONS: TJLB is a safe procedure allowing histological diagnosis of liver diseases. In our cohort, performing 4 cutting procedures during TJLB resulted in a sufficiently high specimen quality, particularly in individuals with liver cirrhosis.

Atherectomy of heavily calcified femoropopliteal stenotic lesions.

PURPOSE: To investigate 1-year outcomes after atherectomy in patients with peripheral arterial disease (PAD) and heavily calcified stenotic lesions. MATERIALS AND METHODS: Thirty-eight patients (mean age, 70 y ± 8; 24 men; TransAtlantic Inter-Society Consensus B-D disease; mean lesion length, 7.5 cm ± 3.5) with PAD (Rutherford score of 2-6) were included in this prospective study. In total, 42 calcified lesions of the superficial femoral artery (SFA) or popliteal artery were treated with the SilverHawk atherectomy device. Thirty-two lesions were located in the proximal or distal 3 cm of the SFA or in the popliteal artery, which were considered segments exposed to high biomechanical stress. Patients were followed up after 6 and 12 months. Clinical reevaluation included measurement of ankle-brachial index (ABI) and duplex sonography. RESULTS: The primary success rate of the procedure was 88%. In five cases, additional balloon angioplasty and/or stent implantation was necessary. Procedure-related embolization occurred in three cases and was treated by aspiration. The mean Rutherford score decreased significantly from 4.1 ± 1.0 to 1.0 ± 1.3 after 12 months. At the same time, the ABI increased significantly from 0.7 ± 0.3 to 0.9 ± 0.3. The primary patency rate was 69% after 1 year. CONCLUSIONS: Atherectomy might be considered as an alternative approach in patients with PAD who have heavily calcified stenotic lesions, especially in areas with high biomechanical stress, where stent implantation is undesirable. Results after 1 year demonstrated a significant decrease of Rutherford score, an increase in ABI, and a reasonable patency rate.

Retroperitoneal abscess with consecutive acute renal failure caused by a lost gallstone 2 years after laparoscopic cholecystectomy.

A 70-year-old male patient presented with abdominal pain, acute renal failure, and fever 2 years after laparoscopic cholecystectomy. During the surgical drainage of the abscess formation on the patient's right flank, a huge gallstone was found in the retroperitoneum. The patient was dismissed from the hospital 11 days after admission with normal lab panel and restored renal function.

Molecular magnetic resonance imaging of deep vein thrombosis using a fibrin-targeted contrast agent: a feasibility study.

PURPOSE: To evaluate the value of a fibrin-specific MR contrast agent (EP-2104R; EPIX Pharmaceuticals) for detection of deep vein thrombosis (DVT) and monitoring of percutaneous intervention for treatment. MATERIALS AND METHODS: In 6 domestic swine, DVT was induced in an iliac/femoral vein using an occlusion-balloon catheter and subsequent injection of thrombin. The occluded vessels were recanalized by mechanical thrombectomy using a Fogarty catheter and an Arrow rotating thrombectomy device. Magnetic resonance imaging of the pelvis and lung was repeated 4 times (before and after DVT induction, after contrast agent administration, and after intervention) using a 1.5-T whole-body XMR system (ACS-NT, Philips Medical Systems, Best, NL). The visualization of the thrombi and contrast-to-noise ratio (CNR) was assessed. RESULTS: EP-2104R allowed selective visualization of thrombi with accurate determination of the extent of DVT with high contrast (CNR: 65.3 +/- 17.2). After intervention, dislodged thrombus fragments were selectively visualized in the lung (CNR: 27.9 +/- 9.3). CONCLUSIONS: Molecular magnetic resonance imaging using fibrin-specific MR contrast agent EP-2104R allowed for selective visualization of DVT and monitoring of percutaneous intervention.

Time-resolved 3D MR angiography of the foot at 3 T in patients with peripheral arterial disease.

OBJECTIVE: The objective of our study was to prove the feasibility and clinical relevance of fast contrast-enhanced time-resolved 3D MR angiography (MRA) with submillimeter spatial resolution at a high magnetic field strength. SUBJECTS AND METHODS: Twenty-one patients (five women, 16 men; mean age +/- SD, 65 +/- 14 years) were examined on a 3-T whole-body MR system with an 8-element phasedarray coil for preoperative evaluation of the pedal arterial system and assessment of the visualized vessels to serve as a graft touch-down site in pedal bypass surgery. Time-resolved 3D MRA of the foot was performed after automatic injection of 0.2 mmol/kg of gadobenate dimeglumine using a sagittal gradient-echo T1-weighted sequence (TR/TE, 4.2/1.6; flip angle, 30 degrees ; field of view, 290 mm; matrix, 352; 120 slices; slice thickness, 0.8 mm) with a spatial resolution of 0.8 x 0.8 x 1.6 mm reconstructed to 0.6 x 0.6 x 0.8 mm and a temporal resolution of 3.9 seconds using keyhole and sensitivity-encoding (SENSE) technology (SENSE factors: 4 in anteroposterior direction and 2 in right-left direction). Dynamic subtractions and rotating maximum intensity projections were calculated. The original image data sets were transferred to a dedicated workstation for objective signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) analysis of the arteries. Subjective image analysis regarding image quality and diagnostic findings was performed by two radiologists in consensus. RESULTS: In all patients, images of diagnostic quality were obtained. Despite the known limitations regarding signal intensity measurements in images acquired with the use of parallel imaging technique, SNR and CNR proved to be excellent, with mean +/- SD values of 294 +/- 158 and 248 +/- 144, respectively. Although most of the patients had diabetic foot syndrome with arteriovenous shunting, the arteries and the potential vessel for bypassing could be clearly separated from the veins in each case due to the temporal information given by our study. The ability to reliably discriminate arteries from veins is of high clinical relevance in planning pedal bypass surgery. CONCLUSION: Fast contrast-enhanced time-resolved 3D MRA of the foot at 3 T is feasible and of high clinical value for the preoperative evaluation of the arterial supply of the foot.

MR imaging of thrombi using EP-2104R, a fibrin-specific contrast agent: initial results in patients.

This study was an initial phase II trial in humans of molecular magnetic resonance (MR) imaging for improved visualization of thrombi in vessel territories potentially responsible for stroke using a new fibrin-specific contrast agent (EP-2104R). Eleven patients with thrombus in the left ventricle (n = 2), left or right atrium (n = 4), thoracic aorta (n = 4) or carotid artery (n = 1) as verified by an index examination (ultrasound, computed tomograpy, or conventional MR) were enrolled. All MR imaging was performed on 1.5 T whole-body MR-system using an inversion-recovery black-blood gradient-echo sequence. The same sequence was performed before and 2-6 h after low-dose intravenous administration of 4 mumol/kg EP-2104R. Two investigators assessed image quality and signal amplification. Furthermore, contrast-to-noise ratios (CNR) between the clot and the blood pool/surrounding soft tissue before and after administration of the contrast agent were compared using Student's t-test. MR imaging and data analysis were successfully completed in 10 patients. No major adverse effects occurred. On enhanced images, thrombi demonstrated high signal amplification, typically at the clot surface, with a significantly increased contrast in comparison to the surrounding blood pool and soft tissue (CNR for clot vs. blood pool, unenhanced and enhanced: 6 +/- 8 and 29 +/- 14; CNR for clot vs. soft tissue, unenhanced and enhanced: 0 +/- 4 and 21 +/- 13; P < 0.01 for both comparisons). EP-2104R allows for molecular MR imaging of thrombi potentially responsible for stroke. High contrast between thrombus and surrounding blood and soft tissues can be achieved with enhanced imaging.

A porcine deep vein thrombosis model for magnetic resonance-guided monitoring of different thrombectomy procedures.

PURPOSE: To establish a porcine model of deep iliac vein thrombosis, which allows monitoring of thrombectomy and thrombolytic procedures by magnetic resonance imaging (MRI). MATERIALS AND METHODS: Deep iliac vein thrombosis was induced in 12 domestic swine using an occlusion-balloon catheter and subsequent injection of thrombin distal to the occluded vessel site. Thrombosis induction was successfully achieved in all animals after 1 hour as verified by MRI. In addition, x-ray fluoroscopy was performed for comparison. Subsequently, thrombectomy was performed using a Fogarty catheter, an Arrow-Trerotola percutaneous thrombolytic device as well as electrical discharge-induced shock waves. The latter procedure was carried out with and without additional administration of Actilyse. MRI and x-ray fluoroscopy were repeated to monitor therapy. RESULTS: After successful thrombosis induction within the deep iliac veins in all cases, thrombus material could be completely removed using the Fogarty catheter and the Arrow-Trerotola percutaneous thrombolytic device, whereas electrical discharge-induced shock wave failed to recanalize the occluded vessel even if additional Actilyse was administered. The actual burden of thrombotic material could be reliably visualized using MRI. CONCLUSIONS: A porcine model of deep iliac vein thrombosis model is presented, which permits reliable visualization of thrombotic material. This model might be a useful tool to compare different thrombectomy devices or to evaluate the effectiveness of new thrombolytic approaches.

Molecular MR imaging of human thrombi in a swine model of pulmonary embolism using a fibrin-specific contrast agent.

OBJECTIVE: Molecular targeted MR imaging of human clots material in a model of pulmonary embolism using a fibrin-specific magnetic resonance imaging contrast agent (EP-2104R, EPIX Pharmaceuticals, Cambridge, MA). MATERIAL AND METHODS: Fresh ex vivo engineered thrombi (human blood) and human clots removed from patients were delivered in 11 swine. Molecular MR imaging with a 3D gradient-echo [3D fast field echo (3DFFE)] sequence and a navigator-gated and cardiac-triggered 3D inversion-recovery black-blood gradient-echo sequence (IR) was performed before thrombus delivery, after thrombus delivery but before contrast media application, and 2 hours after i.v. administration of 4 micromol/kg EP-2104R. MR images were analyzed by 2 investigators and contrast-to-noise ratio (CNR) was assessed. Thrombi were removed for assessment of gadolinium (Gd) concentration. RESULTS: Only after contrast media application were pulmonary emboli [freshly engineered thrombi (n = 23) and human clot material removed from patients (n = 25)] visualized as white foci on MR images. CNR was 13 +/- 3 (ex vivo engineered clot) and 22 +/- 9 (patient clot material) for the fast field echo (FFE)-sequence and 29 +/- 9 (ex vivo engineered clot) and 43 +/- 18 (patient clot material) for the IR-sequence, respectively. A high Gd concentration in the clots was found (82 +/- 43 microM for the freshly engineered and 247 +/- 44 microM for the clots removed from patients, respectively). CONCLUSIONS: EP-2104R allows for molecular MR imaging of human clot material in the pulmonary vessels of a swine model.

Effect of varying slice thickness on coronary calcium scoring with multislice computed tomography in vitro and in vivo.

OBJECTIVES: To compare coronary calcium scoring results (calcium volume, calcium mass, Agatston score, and number of lesions) of different slice thicknesses using a 16-slice CT (MSCT) scanner. MATERIALS AND METHODS: A nonmoving anthropomorphic thorax phantom with calcium cylinders of different sizes and densities was scanned 30 times with repositioning applying a standardized retrospectively ECG-gated MSCT (SOMATOM Sensation 16; Siemens, Forchheim, Germany) scan protocol: collimation 12 x 0.75 mm, tube voltage 120 kV, effective tube current time-product 133 mAs(eff). Fifty patients (29 male; age 57.2 +/- 8.4 years) underwent a nonenhanced scan applying the same scan protocol. Two image sets (effective slice thicknesses 3 mm and 1 mm) were reconstructed at 60% of the RR interval. Image noise was measured in both studies. Calcium volume, calcium mass and Agatston score were calculated using a commercially available software tool. RESULTS: Due to increased image noise in thinner slices, calcium scoring in all scans was performed applying a scoring threshold of 350 HU. In the phantom study, 1-mm slices showed significantly higher scoring results in respect to calcium volume (+8.2%), calcium mass (+12.5%), and Agatston score (+5.3%) (all P < 0.0001). In the patient study, 27 patients had coronary calcifications in 3-mm slices, and 31 patients had coronary calcifications in 1-mm slices. Thinner slices showed significantly higher scoring results in respect to volume (+47.1%), mass (+47.2%), and Agatston score (+29.7%) (all P < 0.0001). CONCLUSIONS: When comparing 3-mm and 1-mm slices in coronary calcium scoring in MSCT, thinner slices lead to significantly increased scoring results.

Malignant right coronary artery anomaly simulated by motion artifacts on MDCT.

OBJECTIVE: The aim of our study was to determine the prevalence of anomalous right coronary artery imitation due to motion artifacts in MDCT. Routine chest MDCT for reasons other than cardiac or vascular imaging is usually performed using breath-hold technique but without retrospective ECG gating and consequently yields pulsating motion artifacts. A possible artifact in front of the aortic root imitates an anomalous right coronary artery originating from the left posterior sinus. This course of the right coronary artery is considered a malignant variant and raises the question of far-reaching consequences such as a bypass operation. SUBJECTS AND METHODS: We performed a prospective study involving 355 patients undergoing routine chest CT examinations. To determine the prevalence of anomalous right coronary artery imitation caused by this motion artifact, all images were evaluated prospectively by an experienced radiologist. RESULTS: Twenty-one patients (5.9%) were suspected of having a malignant variant of the right coronary artery. However, in all patients prior chest CT or additional coronary MR angiography showed a normal origin of the right coronary artery. CONCLUSION: Routine chest MDCT without retrospective ECG gating may produce artifacts around the aorta simulating a malignant variant of the right coronary artery. Considering the low incidence of this malignant interarterial variant, the need for routine chest CT examinations combined with ECG gating and further workup can be disputed from an economic point of view. This artifact should be known to avoid unnecessary further examinations.