[Acute renal failure after gadolinium-containing contrast medium in preexisting chronic renal failure stage II]. / Akutes Nierenversagen nach Gabe eines gadoliniumhaltigen Kontrastmittels bei präexistenter Niereninsuffizienz Stadium II.

BACKGROUND: Gadolinium-containing contrast media in low concentration as normally used in magnetic resonance imaging are considered to be safe in patients with slightly impaired renal function. CASE REPORT: A case of acute renal failure after administration of gadolinium 0.09 mmol/kg body weight in a patient with preexisting mild renal failure (creatinine clearance 55 ml/min) is described. The additional renal damage was partially reversible. CONCLUSION: The reason for the preexisting renal failure was light-chain disease type kappa. This kind of renal damage may be especially susceptible to contrast media toxicity.

Value of fat-suppressed PD-weighted TSE-sequences for detection of anterior and posterior cruciate ligament lesions--comparison to arthroscopy.

OBJECTIVE: To evaluate fat-suppressed (FS) proton-density-weighted (PDw) turbo spin-echo (TSE) magnetic resonance imaging for the detection of anterior and posterior cruciate ligament lesions in comparison to arthroscopy. MATERIALS AND METHODS: In a prospective study 31 knee joints were imaged on a 1.5T MR scanner (Vision, Siemens, Erlangen) prior to arthroscopy using following sequences: (a) sagittal FS-PDw/T2w TSE (TR/TE: 4009/15/105 ms); (b) sagittal PDw/T2w TSE (TR/TE:3800/15/105 ms). Further imaging parameters: slice thickness 3mm, FOV 160 mm, matrix 256 x 256. A total of 62 anterior and posterior cruciate ligaments (ACL/PCL) were evaluated, standard of reference was arthroscopy. Sensitivity, specificity, positive (ppv) and negative predictive value (npv) and accuracy were calculated. RESULTS: Twenty-one cruciate ligament ruptures were detected in arthroscopy, 19 ACL- and 2 PCL-ruptures (on MRI 34/124, 25/62 ACL, 9/62 PCL lesions). For all four sequences in the 31 patients with arthroscopic correlation sensitivity, specificity, ppv, npv and accuracy were 86%, 98%, 95%, 93% and 94% for detection of tears, and 84%, 100%, 100%, 80% and 90% for ACL-ruptures respectively. The two PCL-ruptures were true positive in all sequences, one intact PCL was diagnosed as torn (false positive). CONCLUSIONS: Fat-suppressed PDw/T2w TSE-MR sequences are comparable to PDw TSE sequences for the detection of ACL/PCL-lesions.

Experimental and clinical evaluation of acromioclavicular joint structures with new scan orientations in MRI.

The objective of the study was to evaluate MRI for visualization of acromioclavicular (ac) joint structures in cadaveric shoulders, asymptomatic volunteers and symptomatic patients with trauma of the ac-joint. Three cadaveric shoulders were examined to find adequate planes and sequences for MRI. Afterwards, MR images were correlated to corresponding anatomical sections. Six asymptomatic volunteers and 13 patients were scanned in a 1.5 T Magnetom Vision with three sequences in the following planes: (1) parallel to the clavicle; (2) orthogonal to the ac joint, each time a fat-suppressed proton density-weighted + T2-sequence (TR/TE 4,000/15 ms) was performed; (3) parallel to the clavicle, T1-SE (TR/TE 817/20 ms). The parameters were: slice thickness 3 mm, field-of-view 180 mm, matrix 210x256 pixels. Standard of reference in the patients was clinical examination and conventional X-rays. Classification was by Rockwood grades I-VI. MRI allowed excellent visualization and diagnoses of ac-joint structures in volunteers and patients (n=6 normal, n=1 Rockwood I, n=5 Rockwood II, n=3 Rockwood III, n=4 Rockwood V). On MRI, in one lesion type II and III each, a lower lesion type was suspected clinically and by X-ray. In one patient additional information by MRI led to surgery. MRI allows excellent anatomical display of ac-joint structures and can give clinically relevant information on type and extension of ac-joint trauma, which may influence therapy.

2005 Dr. Gary J. Becker Young Investigator Award: periprocedural oral administration of the leflunomide analogue FK778 inhibits neointima formation in a double-injury rat model of restenosis.

PURPOSE: To test the efficacy of limited oral administration of the new leflunomide analogue FK778 for suppression of neointima proliferation in a double-injury restenosis model in the rat. MATERIALS AND METHODS: For induction of aortic lesions, silicon cuffs were placed operatively around the infrarenal aortas of Lewis rats. After 21 days, the aortic cuffs were removed and the lesions were dilated with 2-F Fogarty catheters inserted via the left common carotid artery. The novel immunosuppressant FK778 was administered at a dose of 5 mg/kg body weight (group 1) or 15 mg/kg body weight (group 2) in a total of 38 animals. For both doses, three different periinterventional time periods, each with a 5-day course of oral FK778, were defined as follows: (i) days -2 to 2, (ii) days 1-5, and (iii) days 7-11, with six or seven rats in each group. After 3 weeks, intima/media ratios were assessed morphometrically and immunohistochemistry for quantification of intimal alpha-actin expression was performed. RESULTS: In both dose groups, there was a trend toward inhibition of neointima formation when the 5-day course of FK778 was started before or 1 day after the intervention. However, in the lower-dose group, inhibition of neointima was not statistically significant regardless of the time frame of treatment (groups 1a-c). With the higher dose, suppression of intimal hyperplasia was significant when FK778 was administered between days 1 and 5 after angioplasty (group 2b; P<.01). Expression of alpha-actin in the intima of FK778-treated rats was significantly reduced when the drug was started 2 days before angioplasty in group 1a (P<.05) or 1 day after angioplasty in both dosage groups (group 1b, P<.01; group 2b, P<.05). CONCLUSION: In the double-injury rat model presented, balloon-mediated proliferation of smooth muscle cells in the intima with consecutive intimal thickening was influenced by FK778 in a dose-dependent manner. However, long-term studies are needed to exclude a delay of vascular healing in this particular model.

Characterization of a new double-injury restenosis model in the rat aorta.

PURPOSE: To characterize a new rat model of restenosis for evaluation of local or systemic drug strategies. METHODS: Arterial lesions were induced by placement of silicone cuffs around the aorta of Lewis rats. After 21 days, the cuffs were removed, and a subgroup of rat aortas was subjected to secondary balloon injury. Remodeling of wall compartments and cell kinetics were assessed morphometrically at 3, 7, 14, 21, and 28 days after the single and double-injury approaches. Immunohistochemistry was used to assess the distribution of macrophages, smooth muscle cells, and proliferating cells within the layers of the arterial wall in the experimental groups versus sham-operated and untreated controls. RESULTS: After cuff placement, the adventitia initially undergoes significant enlargement, while the media shows a reduction in relative thickness. Accumulation of cells within the adventitia at 3 and 7 days is followed by a marked decline in cell density at 14 days, with simultaneously increasing cell numbers in the intima. At this time, activated macrophages are detected in the adventitia, indicating chronic inflammation. Following cuff placement, mild intimal hyperplasia develops. In the double-injury model, extensive neointimal hyperplasia forms rapidly, with a peak at 14 days. CONCLUSIONS: This new double-injury model is technically easy, and multiple experiments can be accrued in short periods of time. It provides an additional platform to identify new targets and strategies for the prophylaxis of postangioplasty restenosis.

Short-term rapamycin for inhibition of neointima formation after balloon-mediated aortic injury in rats: is there a window of opportunity for systemic prophylaxis of restenosis?

PURPOSE: To evaluate the efficacy of limited short-term systemic administration of rapamycin to prevent neointimal intimal hyperplasia (NIH) in a double-injury rat model of restenosis. METHODS: Aortic lesions were induced by perivascular placement of silicone cuffs around the aorta of 36 Lewis rats. After 3 weeks, the cuffs were removed, and the vessels were subjected to secondary balloon injury. Rapamycin (sirolimus) was intravenously administered for 5 days in dosages of 0.5 or 2 mg/kg/d beginning at various time points relative to the balloon injury: (1) days -2 to +2, (2) days 1 to 5, or (3) days 7 to 11. For each treatment period, 6 rats received the 5-day course of the lower or higher dose of rapamycin. Eight rats served as controls undergoing 2-stage injury without rapamycin treatment. Morphometry and immunohistochemistry were performed at 21 days after angioplasty. RESULTS: NIH and intimal alpha-actin expression were inhibited by both dosages when treatment started 2 days before or 1 day after angioplasty. Results were statistically significant for the lower dose when started 1 day after angioplasty (p < 0.01) and for the higher dose when initiated 2 days before the intervention (p < 0.05). Treatment commencing at 7 days did not reduce NIH in either dosage group. CONCLUSIONS: In a double-injury rat model, NIH can be inhibited by short-term systemic rapamycin, but suppression of early cell migration and proliferation is pivotal. A limited peri-interventional antiproliferative therapy may be of value as an adjunct to control restenosis after balloon angioplasty and/or stenting.

The spine in fibrodysplasia ossificans progressiva: a case report.

STUDY DESIGN: A case report of fibrodysplasia ossificans progressiva (FOP). OBJECTIVES: To report a very rare cause of back pain. SUMMARY OF BACKGROUND DATA: FOP is an autosomal dominant disorder with overexpression of bone morphogenetic protein 4 and negative HLA B27. Pathognomonic are congenital malformations of the big toes. METHODS: The authors report on a patient with FOP who presented with back pain at their outpatient clinic. RESULTS: On physical examination, several indurated masses were visible and palpable close to the left and right scapula and the thoracic spine. These were not tender or painful, nor warmed or inflamed. A significantly decreased range of motion of all levels of the spine and the shoulder were found. On the radiographs, segmentation defects of the cervical and lumbar spine as well as synostoses of the spinal processes were seen. The cervical vertebral bodies were small and unusually high. Heterotopic ossifications could be discerned in the lumbar postural muscles and the facet joints of the spine were ankylosed. Additionally to these findings, on the thoracic radiographs ossifications of the muscles of the shoulder girdle could be seen. The pathognomonic shortening of the first metatarsal bone and the proximal phalanx was bilaterally present. The surface shaded 3D-reconstruction of the computed tomography of the trunk showed multiple bulky and confluating ossifications of the shoulder girdle. The spinal processes of the thoracic spine were anklyosed by massive ossifications of the postural muscles. CONCLUSIONS: In FOP, diagnosis can be made by the typical clinical and radiological features.

A rapid-exchange monorail stent system for salvage of failing femoropopliteal bypass grafts.

PURPOSE: To analyze the safety and effectiveness of a new monorail stent system for the treatment of failing femoropopliteal bypass grafts. TECHNIQUE: Acute distal occlusions or stenoses of femoropopliteal bypass grafts were treated with balloon-expandable stents (13 or 18-mm diameter) pre-mounted on a monorail balloon catheter system. The delivery system was assessed subjectively for (1). compatibility with the sheath, (2). lesion crossing potential, (3). radiopacity, (4). flexibility of the catheter, (5). adequacy of stent expansion, and (5). balloon refolding. In 8 failing bypass grafts with distal lesions, the delivery system successfully deployed the stent at the desired location. Sheath compatibility, catheter flexibility, lesion crossing, and stent expansion were rated "excellent" by all examiners for the 18-mm device. Radiopacity of the mounted stent was graded "good" before and during positioning, but only "sufficient" following expansion. For this type of lesion, the investigators rated the overall performance of the device superior to conventional "over-the-wire" systems. CONCLUSIONS: The monorail balloon-expandable stent delivery system provides rapid introduction of the device over the guidewire, and its low profile facilitates the use of small sheaths to minimize access-site complications.

Gadobutrol-enhanced moving-table magnetic resonance angiography in patients with peripheral vascular disease: a prospective, multi-centre blinded comparison with digital subtraction angiography.

The purpose of this study was to compare moving-table three-dimensional contrast-enhanced magnetic resonance angiography (CE MRA), using 1.0-mol gadobutrol, with intra-arterial digital subtraction angiography (i.a. DSA) for evaluation of pelvic and peripheral arteries in patients with peripheral arterial occlusive disease. A total of 203 patients were examined in a prospective, multi-centre study at 1.0/1.5 T. Ten vessel segments of one leg were evaluated on-site and by three independent blinded reviewers off-site. One hundred eighty-two patients were evaluable in blinded reading. For pelvis and thigh, there was statistically significant diagnostic agreement between CE MRA and i.a. DSA on-site (94%) and off-site (86-88%). Overall, for detection of clinically significant stenoses, 93% sensitivity and 90% specificity were achieved in on-site evaluation, with 71-76 and 87-93% off-site; for detection of occlusion, sensitivity and specificity on-site were 91 and 97%, with 75-82 and 94-98% off-site. Evaluation was more sensitive on-site than off-site for detection of stenoses and occlusion, whereas specificity was similar. The CE MRA with 1.0-mol gadobutrol gave results comparable to those of i.a. DSA for the larger arteries of pelvis and thigh. Results for calf arteries were compromised by spatial resolution and technical limitations.

Impaired cerebral glucose metabolism in eclampsia: a new finding in two cases.

The pathophysiology of the reversible neurological manifestation in eclamptic women remains unclear. We report on 2 women with eclampsia who were repetitively examined by (1) transcranial Doppler (TCD), (2) magnetic resonance imaging (MRI) including T1- and T2-weighted images, fluid attenuated inversion recovery sequence, dynamic susceptibility-weighted perfusion imaging and magnetic resonance angiography (MRA), and (3) (18)fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET). In both cases repetitive TCD revealed no signs of vasospasm; the same was true for MRA. MRI perfusion imaging showed completely homogenous cerebral blood flow in both cases. In the initial phase T2-weighted images revealed hyperintensities in both patients (predominantly bilateral frontal and parietal in 1 and in the temporo-occipital subcortex and the basal ganglia in the other). FDG-PET showed inhomogeneous glucose metabolism (GM) in both patients. Primary increased glucose utilization in the hyperintense T2-weighted areas as well as an attenuated GM parieto-occipital were observed in the 1st case; a high GM was found bilaterally in the basal ganglia and an attenuated one in the occipital cortex in the 2nd. In both cases MRI, and FDG-PET normalized within 3 weeks. These case reports document an altered cerebral GM in the presence of homogenous perfusion in eclamptic women. The high GM may be explained by a decoupling of cerebral perfusion and GM, possibly indicating an increased neuronal activity. The attenuation of the GM is most probably due to a deafferentation of cortical neurons.

Hemobahn stent-grafts for treatment of femoropopliteal arterial obstructions: midterm results of a prospective trial.

PURPOSE: To report a prospective study to evaluate safety, effectiveness, and midterm patency of self-expanding stent-grafts in patients with femoropopliteal occlusive disease. MATERIALS AND METHODS: Sixty-three Hemobahn stent-grafts were used in 52 patients for treatment of medium- or long-segment (>3 cm) occlusions (82.7%) and stenoses (17.3%) of the femoropopliteal artery. The mean length of vessel segments covered was 10.9 cm +/- 5.13. Follow-up with documentation of clinical symptoms, assessment of Rutherford clinical stage of peripheral vascular disease, and color-coded duplex sonography was performed at discharge, at 1, 3, 6, 12, 18, and 24 months after implantation, and yearly thereafter. Mean follow-up duration was 23.8 months +/- 6.9 (range, 8-36 mo). Follow-up data at 12 and 24 months after treatment were available for 47 of 52 (90.4%) and 31 of 52 patients (59.6%), respectively. RESULTS: Device implantation was technically successful in all 52 patients, yielding an overall technical success rate of 100%. Procedure-related complications were observed in 12 of 52 patients (23.1%) and consisted of distal embolization (n = 4, 7.7%), minor groin hematoma (n = 7, 13.5%), and arteriovenous fistula (n = 1, 1.9%), but prolonged hospitalization and further medical, interventional, or surgical measures were not required. Stent-graft placement induced an initial improvement of the mean resting ankle-brachial index from 0.54 +/- 0.12 to 0.89 +/- 0.14 (P <.01). Primary patency rates at 12 and 24 months were 78.4% +/- 5.8 and 74.1% +/- 6.2, respectively. Primary assisted patency rates were 82.4% +/- 5.3 at 12 months and 80.3% +/- 5.6 at 24 months. Secondary patency rates at 12 and 24 months were 88.3% +/- 4.5 and 83.2% +/- 5.5, respectively. There was no significant difference (log-rank test, P >.3) between primary patency rates in patients grouped according to lengths of implanted grafts (ie, length of the treated lesions). CONCLUSION: Endovascular placement of Hemobahn stent-grafts for percutaneous treatment of medium- to long-segment high-grade stenoses and occlusions of the femoropopliteal artery is a safe procedure with excellent initial success rates and promising midterm results.

Echo contrast-enhanced transcranial ultrasound: frequency of use, diagnostic benefit, and validity of results compared with MRA.

BACKGROUND AND PURPOSE: The present study was undertaken to determine the frequency of use of the ultrasound contrast agent (UCA) Levovist in routine transcranial ultrasound (TU). Additionally, we evaluated the diagnostic validity of contrast-enhanced TU using 3-dimensional time of flight MR angiography. METHODS: Indication for the UCA was an insufficient evaluation of the intracranial arteries after a combined approach with transcranial color-coded Duplex and transcranial Doppler examination. We prospectively analyzed every patient referred for TU over 6 months. Additionally, over a 3-month period, TU results were compared with 3-dimensional time-of-flight MR angiography. RESULTS: Indication for use of UCA was met in 61 of 687 patients (8.8%). After UCA application, a diagnostic result was achieved in 75% of cases during transtemporal and in 81% during transforaminal insonation. The sensitivity and specificity of TU in the diagnosis of intracranial stenosis were 83% and 82%, respectively. CONCLUSIONS: Use of UCA was necessary in 8.8% of the patients. A diagnostic benefit was achieved in 75% to 80% of cases. Contrast-enhanced TU demonstrated a high sensitivity and specificity in the diagnosis of intracranial stenosis.

Bilateral leg ischemia due to descending aortic dissection: combined treatment with femoro-femoral cross-over bypass and unilateral aorto-iliac stenting.

We report a case of aorto-iliac occlusion due to descending aortic dissection treated initially with femoro-femoral cross-over bypass and secondarily with unilateral aorto-iliac stenting because of progression of the dissection. A 75-year-old man presented with acute ischemia of the right leg. CT revealed occlusion of the right iliac artery due to descending aortic dissection with a clotted false lumen. Three days after femoro-femoral cross-over bypass, ischemia of both legs developed and angiography demonstrated occlusion of the infrarenal aorta and left common iliac artery. Two overlapping stents were deployed in these vessel segments. Completion angiography confirmed successful recanalization with adequate distal flow and good patency of the cross-over bypass. Peripheral pulses were restored and the patient's symptoms were alleviated. Combined treatment with cross-over bypass and endovascular recanalization may be considered as a viable alternative to open aortic surgery in selected cases of complicated aorto-iliac dissection with bilateral leg ischemia.

Post-partum cerebral angiopathy: repetitive TCD, MRI, MRA, and EEG examinations.

We report of a woman with post-partum cerebral angiopathy (PCA), in whom we repetitively performed transcranial Doppler sonography (TCD), MR imaging (MRI), and MR angiography (MRA) to evaluate the underlying pathophysiology. A 31-year-old woman, Gemini pregnant, complained of severe throbbing frontal headache four days after an uneventful delivery by Cesarean section. Blurred vision occurred eight days after delivery, followed by three generalized tonic-clonic seizures. Neurological examination revealed a somnolent woman without focal neurological deficits. At the day of the seizures increased flow velocities and disturbed flow were observed in the right posterior and anterior cerebral artery on transcranial Doppler (TCD). MRI showed infra- and supratentorial patchy hyperintensities in T2-weighted images and in the FLAIR sequence. Diffusion-weighted imaging revealed corresponding multi-focal hyperintense areas indicating increased diffusion and MRA showed a diffuse multisegmental narrowing of all pial arteries. MRI at day 10 was completely normal, but MRA still revealed vascular narrowing in the right posterior cerebral artery. General slight flow accelerations in all basal arteries occurred after 10 days and lasted for three weeks. PCA is apparently associated with a vascular narrowing causing cerebral ischemia with increased diffusion. Later reactive cerebral hyperperfusion is observed. Vascular narrowing and cerebral hyperperfusion still persist after MRI has normalized.

Lethal hemorrhage caused by aortoenteric fistula following endovascular stent implantation.

A 55-year-old women developed an aortointestinal fistula between the bifurcation of the aorta and the distal ileum following implantation of multiple endovascular stents into both common iliac arteries for treatment of aortoiliac occlusive disease. Ten months before the acute onset of the gastrointestinal hemorrhage two balloon-expandable steel stents had been implanted into both common iliac arteries. Due to restenosis and recurrent intermittent claudication, three balloon-expandable covered stents were implanted 4 months later on reintervention. The patient presented with abdominal pain and melena, and fell into hemorrhagic shock with signs of upper gastrointestinal bleeding. After transfer to our hospital, she again developed hemorrhagic shock with massive upper and lower gastrointestinal bleeding and died during emergency laparotomy. The development of aortoenteric fistulas following endovascular surgery/stent implantation is very rare and has to be considered in cases of acute gastrointestinal hemorrhage.

Endovascular placement of self-expanding nitinol coil stents for the treatment of femoropopliteal obstructive disease.

PURPOSE: To report on a prospective two-center study to evaluate safety and effectiveness of a self-expanding nitinol coil stent in patients with femoropopliteal obstructive disease. MATERIALS AND METHODS: The IntraCoil nitinol stent was used in 37 patients (28 men and nine women; mean age, 62.4 y plus minus 10.7; range, 43-81 y) presenting with high-grade stenoses (n = 23) or short (<3 cm) occlusions (n = 17) of the superficial femoral artery (SFA; n = 33) or popliteal artery (n = 4). Indications for stent placement were significant residual stenosis (>30%) or dissection after angioplasty. Follow-up evaluations with measurement of the Doppler ankle-brachial index (ABI), assessment of Rutherford clinical stage, and color-coded duplex sonography were performed at discharge and 1, 3, 6, 12, and 18 months thereafter. Primary endpoints of the study were immediate technical and clinical success and 1-year patency. RESULTS: Initial technical success was achieved in all patients. In 10 patients (27%), more than one 40-mm-long device had to be implanted for total lesion coverage; in three patients (8.1%), stents were placed in two separate segments of the SFA simultaneously. The total number of stents deployed was 50. Stent placement induced an initial improvement of the ABI from 0.54 plus minus 0.2 to 0.92 plus minus 0.11 (P <.01). Follow-up data for 12 months after treatment are available for 29 of 37 patients (78.4%); mean follow-up is 15.6 months (range, 1-26 mo). Primary patency rates at 6 and 12 months were 97.1% (SE = 2.9) and 86.2% (SE = 6.5). The primary assisted patency rate was 100% at 12 months. CONCLUSION: Endovascular placement of the IntraCoil self-expanding nitinol coil stent for salvage of failed angioplasty in patients with femoropopliteal obstructive disease is an effective and safe procedure with promising mid-term results.