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We prospectively evaluated the feasibility and technical properties of a dedicated interventional magnetic resonance (MR) imaging protocol for near-real-time MR fluoroscopy-guided bilateral lumbar facet joint injections. A total of 44 facet joint injections were performed in 22 patients using a C-shaped open 0.2-T MR imaging system (Magnetom Concerto, Siemens Medical Solutions, Erlangen, Germany). A T1/T2-weighted fast-imaging-with-steady-precession (FISP) sequence with an end-to-end latency of 1.2 s facilitated sufficient near real-time MR imaging guidance in all cases. A T1-weighted two dimensional fast-low-angle-shot (FLASH2D) MR sequence identified final needle tip location. Different angles of the needle path had only minimal influence on the appearance of the needle artifact produced by both sequences, resulting in a symmetrical needle tip artifact. The joint cavity was successfully punctured in 79.5% (35/44) of joints, which was followed by intra-articular fluid accumulation in 75% (33/44). Inaccessible joints demonstrated a significantly (p=0.044) higher number of posterior osteophytes (66.7%, 6/9 joints) compared to accessible joints (26%, 9/35 joints). No complications occurred. Table time showed significant shortening over time with average table time of 33 (21-68.5) min. We conclude that MR fluoroscopy-navigated lumbar facet joint injections are feasible and safe. [ABSTRACT FROM AUTHOR]

Whooping cough, or pertussis, is a highly communicable infectious disease caused by the bacterium Bordetella pertussis. Vaccination once reduced the incidence of the disease, but a global resurgence of the infection happened during the past two decades, likely due to the waning immunity of vaccination. Macrolides such as erythromycin and azithromycin are the drugs of primary choice for treatment. In this personal view, we call for attention to macrolide-resistant B. pertussis (MRBP), which has emerged and prevailed in mainland China for years and are exclusively mediated by mutations in the 23S rRNA gene. Whether the prevalence of MRBP in China results from overuse of azithromycin in clinical medicine remains unknown. The incidence of MRBP is low in other countries, but this could be a technical illusion since China employs culture as the mainstream diagnostic method whereas nucleic-acid amplification test being widely used in other countries fail to test antimicrobial susceptibility. Given the increasingly frequent global travel that facilitates microbial transmission worldwide, there is a pressing need to perform international surveillance on MRBP to prevent the potential circulation of the organism. Finding alternative agents that possess good activity against B. pertussis is also urgently required., Competing Interests: Dr Feng declares no competing interests. During the conduct of the study, Dr. Chiu has received honoraria from Sanofi Pasteur, MSD, and Pfizer; Dr. Heininger and Dr. Hozbor have received honoraria from Sanofi Pasteur; Dr. von König has received honoraria from Sanofi Pasteur, GSK Biologicals SA, MSD, and Norvatis Vaccines. Dr. Tan has received grant from Sanofi Pasteur. Outside the submitted work, Dr. Tan has received grants from Merck, Pfizer, and Glaxo-Smith Kline., (© 2021 The Authors.)

Pertussis is a vaccine-preventable disease that causes morbidity and mortality, particularly in infants and children <5 years of age. The Global Pertussis Initiative (GPI) recommendations represent a systematic evaluation and prioritization of strategies to prevent pertussis-related infant and child deaths, reduce global disease burden and prevent resurgence through vaccination strategies and public health policies at national, regional and local levels. The GPI recommendations are based on clinical trials and observational and surveillance data, which are essential in the planning, implementation and evaluation of vaccination practices and best use of available resources. Many low- and middle-income countries (LMIC) continue to use whole-cell pertussis (wP) vaccines for primary vaccination, while most high-income countries have replaced wP with the less-reactogenic acellular pertussis (aP) vaccines. This present manuscript pertains to discussions held during the GPI's meeting on November 11-13, 2016, in Cape Town, Republic of South Africa. The GPI recommends that LMIC aim for high coverage of infant series pertussis vaccines as a priority. In LMIC and countries with constrained vaccine funding, if wP vaccines are currently used, wP should continue to be used. Furthermore, given that protection against disease and death due to pertussis in neonates is a key priority of the GPI, it recommends that ap immunization in pregnancy should be implemented as a priority in all countries if resources allow. Given that surveillance and epidemiology data on which to base vaccine decisions are important, the GPI also suggests that, in areas where wP vaccines are implemented, standardization and calibration of wP vaccines are checked, considering the many different manufacturers and variable standards of production and quality control. In addition, as immunity to pertussis wanes following the primary infant series of vaccination, the GPI further recommends that toddlers, adolescents, healthcare and childcare workers receive booster vaccine doses, where resources allow., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Pertussis remains a major cause of morbidity and mortality, particularly in infants and young children, and despite the availability of vaccines and pertinent national and international guidelines. The disease burden is more severe in low- and middle-income countries (LMICs), especially in the African continent. Pertussis is more prevalent among young infants in Africa. Poor or no pertussis surveillance, lack of disease awareness, diagnostic limitations, and competing health priorities are considered key contributory factors for this high pertussis burden in Africa. Most African countries use whole-cell pertussis (wP) vaccines, but coverage with three primary doses of diphtheria-tetanus-pertussis vaccines falls short of the World Health Organization's recommended goal of >90%. The Global Pertussis Initiative (GPI) works toward developing recommendations through systematic evaluation and prioritization of strategies to prevent pertussis-related infant and child deaths, as well as reducing global disease burden to acceptable national, regional, and local levels. For countries using wP vaccines, the GPI recommends continuing to use wP to improve primary and toddler booster vaccination coverage. Vaccination during pregnancy is the next priority when acellular pertussis (aP) vaccines and other resources are available that directly protect newborns too young to be vaccinated, followed by, in order of priority, booster doses in older children, adolescents, healthcare workers and finally, all adults. Improved surveillance should be a high priority for African LMICs assessing true disease burden and vaccine effectiveness to inform policy. More research is warranted to evaluate the safety and efficacy of wP and aP vaccines and strategies, and to determine their optimal use., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Unlabelled: Since the introduction of endovascular aneurysm repair (EVAR) in 1991, the endovascular therapy with newest stent grafts has assumed a prominent role in the clinical management of abdominal aortic aneurysms (AAA) with a superior perioperative mortality of EVAR and an equivalent mid-term outcome, compared to open surgery. Newest techniques using chimney or periscope grafts and customized fenestrated and branched stent grafts allow the endovascular treatment of complex pararenal AAA. This article reviews EVAR in the treatment of AAA, evidence based results and advanced indication by newest interventional techniques and technical developments., Key Points: • EVAR has become standard treatment of abdominal aortic aneurysm with equivalent results to open surgery.• Technical advancements and the introduction of newest stent grafts continually expand the indication of EVAR.• Chimney- and periscope grafts as well as custom-made prothesis systems allow endovascular treatment of complex para- and suprarenal aneurysms., (© Georg Thieme Verlag KG Stuttgart · New York.)

Purpose: To report the safety and diagnostic performance of magnetic resonance (MRI)--guided core biopsy of osseous lesions in children with chronic recurrent multifocal osteomyelitis (CRMO) that were visible on MRI but were occult on radiography and computed tomography (CT)., Materials and Methods: A retrospective analysis of MRI-guided osseous biopsy performed in seven children (four girls and three boys; mean age 13 years (range 11 to 14) with CRMO was performed. Indication for using MRI guidance was visibility of lesions by MRI only. MRI-guided procedures were performed with 0.2-Tesla (Magnetom Concerto; Siemens, Erlangen, Germany; n = 5) or 1.5-T (Magnetom Espree; Siemens; n = 2) open MRI systems. Core needle biopsy was obtained using an MRI-compatible 4-mm drill system. Conscious sedation or general anesthesia was used. Parameters evaluated were lesion visibility, technical success, procedure time, complications and microbiology, cytology, and histopathology findings., Results: Seven of seven (100%) targeted lesions were successfully visualized and sampled. All obtained specimens were sufficient for histopathological analysis. Length of time of the procedures was 77 min (range 64 to 107). No complications occurred. Histopathology showed no evidence of malignancy, which was confirmed at mean follow-up of 50 months (range 28 to 78). Chronic nonspecific inflammation characteristic for CRMO was present in four of seven (58%) patients, and edema with no inflammatory cells was found in three of seven (42%) patients. There was no evidence of infection in any patient., Conclusion: MRI-guided osseous biopsy is a safe and accurate technique for the diagnosis of pediatric CRMO lesions that are visible on MRI only.

Purpose: To evaluate CT-guided radiofrequency (RF) ablation of osteoid osteoma using internally cooled monopolar RF electrodes for technical success, complications and clinical long-term success., Materials and Methods: Between April 1999 and July 2006, 23 patients were treated under general anesthesia with CT-guided RF ablation using an internally cooled monopolar single RF electrode (Cool-tip, Valleylab, TycoHealthcare, Boulder, USA; active tip: 10 mm). For the removal of the nidus, we used either a manual or an automated drill. The technical success was evaluated by a CT scan (MSCT, Siemens Medical Solutions, Forchheim). The clinical long-term success was investigated by questioning patients prior to discharge, and after 6, 12 and 18 months. After 18 months, patients were interviewed on an annual basis., Results: The technical success rate was 100 %. The nidus was located in n = 19 cases at the lower extremity and in n = 4 cases at the upper extremity. Minor complications were observed for n = 2 patients. The mean hospitalization time was 1.5 d (1-2 d). The mean follow-up was 75.9 months (18-120 months) for n = 23 patients. No local recurrence was observed. One patient had intermediate pain one week after RF ablation without recurrent symptoms., Conclusion: CT-guided RF ablation using an internally cooled monopolar single RF electrode is an effective and safe minimally invasive method for the treatment of osteoid osteoma with excellent clinical long-term success., (© Georg Thieme Verlag KG Stuttgart · New York.)

If low back pain does not improve with conservative management, the cause of the pain must be determined before further therapy is initiated. Information obtained from the patient's medical history, physical examination, and imaging may suffice to rule out many common causes of chronic pain (eg, fracture, malignancy, visceral or metabolic abnormality, deformity, inflammation, and infection). However, in most cases, the initial clinical and imaging findings have a low predictive value for the identification of specific pain-producing spinal structures. Diagnostic spinal injections performed in conjunction with imaging may be necessary to test the hypothesis that a particular structure is the source of pain. To ensure a valid test result, diagnostic injection procedures should be monitored with fluoroscopy, computed tomography, or magnetic resonance imaging. The use of controlled and comparative injections helps maximize the reliability of the test results. After a symptomatic structure has been identified, therapeutic spinal injections may be administered as an adjunct to conservative management, especially in patients with inoperable conditions. Therapeutic injections also may help hasten the recovery of patients with persistent or recurrent pain after spinal surgery., (RSNA, 2007)

Purpose: To evaluate the efficacy and specific properties of MR imaging-guided corticosteroid infiltration of the sacroiliac (SI) joints in the treatment of therapy-refractory sacroiliitis in patients with ankylosing spondylitis., Materials and Methods: In this study, 26 patients were prospectively included. Inclusion criteria were AS with therapy refractory acute sacroiliitis and inflammatory back pain > or = 6 months. The intervention was performed using an open low-field MR-scanner. Inflammatory back pain was assessed on a visual analog scale (VAS). Success of the therapy was defined as an absolute reduction of the VAS score or = 35 % and persisting improvement > or = 2 months. The grade of sacroiliitis was documented using high-field MR imaging. Variables were compared using McNemar test and Wilcoxon test. The mean remission time was calculated using a Kaplan-Meier analysis. A p-value < 0.05 was considered statistically significant., Results: The intervention was technically successfully performed in all patients. Following MR imaging-guided corticosteroid infiltration of the SI joints, the VAS score improved from 8 (5 - 10) points to 4.5 (0 - 8) points (- 44 %) in all patients (n = 26), which was statistically significant (p < 0.001). Of 26 patients, 22 (85 %) fulfilled the predefined criteria for successful therapy. This group had a statistically significant (p < 0.01) improvement of the VAS score from 8 (6 - 10) to 3 (0 - 5) (- 63 %). Improvement was seen after 7 (1 - 30) days. There was a marked reduction of the subchondral bone marrow edema (- 38 %). The mean remission time was 12 (4 - 18) months., Conclusion: MR imaging-guided corticosteroid infiltration of the SI joints proved to be an effective therapy of inflammatory back pain in patients with therapy refractory AS. With the ability of multiplanar imaging, precise localization of the bone marrow edema and the lack of ionizing radiation, interventional MR imaging currently represents the superior method for the treatment of the predominantly young patient group presenting with ankylosing spondylitis. Owing to short intervention times, open MR-scanners are ideally suited for MR imaging-guided infiltration of the SI joints.

Magnetic resonance (MR)-guided liver biopsy was performed in three patients with hepatocellular carcinoma. The tumor was considered (n = 2) or proven (n = 1) inaccessible with ultrasound or computed tomographic guidance. Because all lesions were poorly delineated on nonenhanced MR imaging, contrast agents (Gd-BOPTA, n = 1; ferucarbotran, n = 2) were applied to facilitate biopsy in an open low-field scanner. Postcontrast tumor conspicuity was fair in the patient receiving Gd-BOPTA and excellent in both patients receiving ferucarbotran, and biopsy was successful in all cases.

Purpose: To evaluate the deliverability and protection capabilities of an embolism protection filter in angioplasty of peripheral arteries., Methods: The Angioguard emboli capture guidewire system was applied in 11 patients with femoropopliteal lesions (6 stenoses, 3 occlusions, 2 controls). Data on lesion crossing, flow deceleration and macroembolization were recorded. Filter membranes were evaluated with scanning electron microscopy (SEM)., Results: System delivery was successful in all patients. Primary lesion crossing was feasible in four of six stenoses; predilatation was required in two of six. Marked flow deceleration was recorded in six patients. Emboli next to the filter were detected in each patient with concentric plaques, but could not reliably be removed with the filter. Downstream macroembolization was also present in all patients with concentric stenoses, but in none with chronic occlusion. None of the patients had clinical signs of ischemia. SEM analysis demonstrated only small particles on control group filters and non-obliterating fibrinous conglomerates on filters used in chronic occlusion. Substantial obliteration was seen on several filters used in stenotic lesions., Conclusion: Microembolization of fibrin aggregates is a common incident in balloon angioplasty of femoropopliteal stenoses. Macroembolization occurred more frequently than previously reported. The use of embolism protection filters aided in the detection but not in the removal of larger emboli.

Purpose: To compare the effectiveness of pulsed (impedance control mode) and non-pulsed (manual control mode) radiofrequency ablation (RFA) by using an internal cooled-clustered electrode., Materials and Methods: Ex vivo RF ablations (n = 93) were performed with a 200 W RF generator (Model-Cooled Tip, Radionics, USA) in 10 bovine livers, using the impedance and manual control mode. In the impedance control mode, the generator automatically adjusted the applied RF power to the tissue impedance measured during RF ablation. In the manual control mode, the application of the RF power was constant. Both applications were investigated in a capacity range between 5 and 200 W. The duration for each RF ablation was between 2 and 60 minutes. After RF ablation, the short axis diameter of the necrosis was determined macroscopically and the peripheral zone of the necrosis histologically., Results: The impedance control mode produced lesions with short axis diameters of 5.3 +/- 0.3 cm at a power of 200 W after 60 minutes of RF ablation and the manual control mode lesions with short axis diameters of 4.1 +/- 0.4 cm at a power of 70 W after 8 +/- 2 minutes of RF ablation. The impedance control mode increased significantly the time of RF ablation with higher power and the size of necrosis (p < 0.01)., Conclusion: In comparison to non-pulsed RF ablation, pulsed RF ablation with internal cooled-clustered electrodes significantly increases the size of the lesions and represents a methodical optimization in our opinion.

Objective: The aim of our study was to test the feasibility and specific properties of MR imaging-guided adrenal biopsy using an open 0.2-T scanner and MR fluoroscopic fast imaging with steady-state free precession sequences., Conclusion: MR imaging-guided biopsy of the adrenal gland is feasible and safe. In all patients, appropriate specimens were obtained with full diagnostic yield and accuracy. MR fluoroscopy is particularly useful to establish an oblique paravertebral access without pleural transgression. For final needle placement, supplementary breath-hold multislice sequences are required in most cases.

Rationale and Objectives: To test utility and specific properties of a commercially available MRI compatible power drill for MR guided transcortical bone biopsy., Methods: In 17 patients MR-guided bone biopsy was performed in an open low-field scanner (0.2 T), using a piezoelectrically powered drilling machine. Target lesions were osteoblastic in four and nonsclerosed intramedullary in 13 cases. Titanium drills sized 3 to 4 mm and an outer cannula were coaxially used for power assisted cortical trephination. For intramedullary lesion sampling, spring loaded biopsy guns and sharpened cannulas were additionally applied in seven and fluid aspiration in two patients, respectively., Results: The piezoelectric device proved to be fully MR compatible. Trephination and subsequent biopsy was successful in all patients without major complications. The drilling procedure could entirely be performed inside the magnet in case of a lateral approach (n = 11). The net drilling time averaged 7.8 minutes for trephination of nonimpaired diaphyseal bone, but was up to 50 minutes in case of thickened femoral bone. Procedures were complicated by frequent drill loosening, drill obstruction by cortical bone (n = 4) and impaired periosteal grip (n = 5) with damage to the outer cannula (n = 3)., Conclusions: The piezoelectric power drill can be applied safely in a low-field MRI environment and is a valuable tool to facilitate transcortical bone biopsy.

The aim of this study was to demonstrate the feasibility of MR-guided lumbar sympathicolysis (LSL) in a non-selected patient population. One hundred one MR-guided LSL procedures were performed in 89 patients according to Haaga's technique using a horizontally open clinical MR system (0.2 T) and non-ferromagnetic 20-G cannulas (neurolysis, n=93; blockade, n=8). Only gradient-recalled sequences in either single or multislice mode [fast imaging with steady-state precession (FISP) and fast low-angle shot] were applied for anatomical survey and needle guiding. Bupivacaine injection was monitored with MR fluoroscopically. Fluid distribution was subsequently documented in a CT scan in 65 patients. Ninety-one LSL procedures could be successfully completed. Ten patients were not treated using MR due to patient inconvenience, severe motion artifacts ( n=4 each), excessive spondylophytes, and retroperitoneal hematoma ( n=1 each). One case of ureteral necrosis occurred. Motion artifacts were rated less severe in single-slice FISP sequences and in obese patients. An average of 3.48 sequence measurements were required for definitive needle placement. Average table time was 32.3 min. An MR-guided LSL is feasible and can be performed with acceptable safety and time effort. It can be recommended for repeated sympathetic blockades in younger patients to avoid cumulative irradiation associated with CT guidance.

Purpose: To evaluate the diagnostic value of multidetector CT angiography (MDCTA) of the renal arteries., Methods: 27 patients underwent MDCTA of the renal arteries. Scan parameters were: collimation 4 x 1 mm, pitch 1.5, effective slice thickness 1.25 mm, reconstruction increment 0.8 mm, circulation time measurement, power injection of 80 ml iomeprol 400, flow 4 ml/sec. Independent reading on laser film was done by two radiologists using edited maximum intensity projections, multiplanar reconstructions and source images. Standard of reference was a 3D-FLASH MR angiography (1.5 T, 3.9/1.2, 10 degrees 0.2 mmol GdDTPA/kg bw) in 10 and intraarterial angiography in 17 patients., Results: Analysing 63 arteries, sensitivity, specificity, positive predictive value and negative predictive value in terms of detection of moderate and high grade renal artery stenosis (n = 10) were 90, 98, 90 and 98 % for reader A, and 90 % each for reader B, respectively (kappa = 0.91 interobserver agreement). 1/11 accessory renal arteries was missed by both angiography and MDCTA. Image quality was graded as excellent or good in 26/27 of cases by both readers., Conclusion: MDCTA proved to be a highly accurate tool in the detection of therapeutically relevant renal artery stenosis.

Objective: To evaluate the technical performance and delivery characteristics of the Palmaz-Corinthian stent for endovascular therapy of atherosclerotic renovascular disease., Methods: 61 patients underwent implantation of 76 Palmaz-Corinthian (PC) stents in 72 arteries. 50 original PC and 26 PC stents with the modified IQ-design were employed. The indications comprised primary stenting of ostial (n = 49) or truncal (n = 1) stenosis or occlusion (n = 3), and selective stenting following complicated (dissection, n = 4) or unsuccessful (n = 8) angioplasty. The remaining stents were placed in patients with recurrent stenosis (n = 5) or acute aortic dissection (n = 2) involving the renal artery. Mean severity and length of stenosis were 81.3% and 9.8 mm, respectively. 39 lesions were rated eccentric or calcified. Data on technical success, complication rate, delivery characteristics and ease of placement compared to standard renal stents were retrieved from a prospective multicenter registry., Results: Stent delivery was successful in all patients, major complications were not reported. Stent placement was suboptimal in 7 of 72 cases: 4 stents were located too distally in the renal artery, necessitating proximal coaxial overstenting in 2 cases. The distal part of the stenosis was incompletely covered and the orifice of a segmental branch inappropriately overstented in one case each. One stent was dislodged from the balloon, resulting in stent protrusion in the aortic lumen. Significant residual stenosis after stenting was not observed. Overall stent deliverability, trackability and potential repositioning inside the stenosis were rated positive, radio-opacity was rated superior for the IQ design., Conclusion: Technical performance and delivery characteristics of the Palmaz-Corinthian stent have been significantly improved compared to the Palmaz design, allowing mostly correct placement in renal artery stenoses with a low complication rate.

Langerhans' cell histiocytosis (LCH) is a disorder of histiocytic proliferation that primarily affects infants. Imaging findings of a rare case of lung and liver involvement in an adult are presented. High-resolution computed tomography (HRCT) of the lungs showed confluent thin-walled cystic air spaces compatible with advanced LCH. Liver CT and MRI revealed unspecific signs of fatty infiltration. Irregular widening of peripheral bile ducts was displayed in breath-hold MR cholangiography. This pattern is considered characteristic for sclerosing cholangitis and should support the diagnosis of LCH in case of concomitant cystic pulmonary disease, even in adult patients.

Primary liver tumors are one of the most common malignant tumors worldwide. Surgical resection of the tumors is considered the only potentially curative therapy. It has been estimated that only 20%-30% of patients with HCC (hepatocellular carcinoma) are surgical candidates. For this reason a number of alternative therapies have been used for the treatment of HCC. These include transarterial chemoembolisation (TACE), percutaneous alcohol instillation (PAI) and thermal ablative techniques. Thermal ablation for the treatment of HCC include both freezing (cryoablation) and heating (radiofrequency, microwave, laser and high-intensity focussed sonography) techniques. Of these techniques, percutaneous radiofrequency ablation (PRFA) is increasingly used for the local tumor destruction. The low rate of complications and the technical development increasing the efficacy of PRFA have shown that this is a very promising and safe technique.

Purpose: To evaluate feasibility, safety and efficacy of percutaneous radiofrequency ablation (RFA) of hepatic neoplasms using a clustered electrode., Material and Methods: Percutaneous, CT-guided RFA using a clustered electrode was performed in 12 patients with a total of 15 hepatic neoplasms (2.0-6.0 cm in diameter)., Results: A total of 17 percutaneous RFA was performed. The mean total procedure time was 2.0 h (1.5-2.5 h). Placement of the clustered electrode within the neoplasms using a inter- or subcostal approach under local anesthesia was possible in all cases. Complications related to percutaneous treatment and technical problems were not encountered. Diameter of the ablated areas ranged between 3.0-7.0 cm. Technical success was observed in 13 of 15 neoplasms (86.6%). During a mean follow-up of 7.25 months (range 3-12 months) 8 of 12 neoplasms showed a complete necrosis., Conclusion: Percutaneous RFA using a clustered electrode is a feasible, safe and effective procedure for the treatment of hepatic neoplasms up to 6 cm in size.

Purpose: To evaluate the effect of permanent occlusion of the hepatic artery on the efficacy of transarterial chemoembolization (TACE) in an animal model., Material and Methods: 12 days after inoculation of the Morris hepatoma 3924 A in 15 male ACI rats, TACE with Mitomycin C (0.25 mg/kgBW) + Lipiodol (0.2 ml/kgBW) without (n = 5) and with permanent occlusion of the hepatic artery (n = 5) was performed. Control group consisted of 5 rats. Tumor volume was determined by MRI (1.0 T, T1 [TR/TE, 400/14 ms]) before and 12 days after therapy., Results: Compared to the control group, TACE without and with permanent occlusion of the hepatic artery showed a significant reduced tumor growth after 12 days (p = 0.017 and p = 0.005). However, permanent occlusion did not improve the retarding effect on tumor growth (p = 0.9)., Conclusion: The effectiveness of TACE in an animal model using a cytostatic-/lipiodol-emulsion is not improved by permanent occlusion of the hepatic artery.

Purpose: To evaluate MR-cholangiography after instillation of contrast media via indwelling biliary tubes., Methods: In 8 patients with stenoses of the central bile ducts, physiological saline solution and diluted contrast media (Gd-DTPA, 5 mmol/l) were consecutively administered via an indwelling biliary tube. MR cholangiograms were obtained before and after saline injection using a HASTE-sequence and after administration of Gd-DTPA using a T1-weighted gradient echo sequence., Results: Peripheral bile ducts were better visualised in the water-sensitive approach than after Gd-DTPA enhancement. In patients with short-time drainage bile duct definition was poor due to periportal oedema. Visualisation of peripheral bile ducts could be improved by injection of saline solution in these patients. After administration of Gd-DTPA via the biliary tube contrast enhancement of the central bile ducts was achieved in all patients except for one patient on long-term drainage with an indwelling Yamakawa tube., Conclusion: T1-weighted visualisation of the central bile ducts can be achieved by means of injection of Gd-DTPA via indwelling biliary tubes.

Purpose: To enhance flow signals in the deep veins of the lower extremity by means of a drip infusion., Methods: Saline solution and diluted contrast media were consecutively administered in 8 healthy volunteers by drip infusion (3 ml/min) via the cubital vein. Imaging of the deep veins in both legs was performed using a gradient echo sequence with flow compensation. Changes of the intravascular signal-to-noise-ratio (SNR) were correlated with the duration of the drip infusion., Results: Improved SNR were detected in each level examined in both thigh and calf. SNR increases up to 157% were opposed to decreases of less than 16%. The average rise of SNR was up to 55% in the calf veins., Conclusion: Saline drip infusion is a simple and valuable method for enhancement of venous flow signals and should be administered routinely in time-of-flight venographies.