Dynamic contrast-enhanced MR tomoangiography of major pulmonary arteries

We evaluated the use of contrast-enhanced MR tomoangiography of the major pulmonary arteries in patients with suspected pulmonary embolism and hilar lung carcinoma. Patients with acute pulmonary emboli of the major pulmonary arteries, pulmonary hypertension (n = 11), and hilar lung carcinoma with suspected infiltrated pulmonary artery (n = 4), underwent MRI after selective digital subtraction pulmonary angiography (DSA). Subsecond contrast-enhanced MR tomoangiograms were obtained in the long axis of each pulmonary artery after bolus injection of a paramagnetic MR contrast agent. All proximal thrombi visualized using DSA (n = 13) were depicted using contrast-enhanced MR tomoangiography. Pulmonary artery obstruction (n = 2) or stenosis (n = 2) by the tumor were similarly assessed by DCMRA and DSA. Contrast-enhanced MR tomoangiography allows a reproducible, fast, dynamic, and multiplanar good quality imaging of the major pulmonary arteries and their proximal branches. This technique may be useful in patients with pulmonary hypertension for whom DSA is dangerous, and in the diagnosis of malignant involvement of central pulmonary arteries.     

Contrast-enhanced subtraction MR angiography in occlusive disease of the pelvic and lower limb arteries: results of a prospective intraindividual comparative study with digital subtraction angiography in 76 patients.

PURPOSE: The purpose of this work was to evaluate the feasibility and clinical use of MR angiography (MRA) for examining the pelvic and lower limb arteries in patients with arterial occlusive disease. METHOD: Seventy-six patients with clinical signs of peripheral arterial occlusive disease were included in the study. MRA was performed using a fast contrast-enhanced high-resolution 3D technique that covered the area from the distal abdominal aorta to the distal lower limbs in two examination steps. RESULTS: In all patients, diagnostic images comparable with those of conventional intraarterial digital subtraction angiography (DSA) could be obtained. No false-negative findings were seen in the iliac, femoral, or popliteal arteries. Ten to 16% of the mild stenoses and 6-14% of the severe stenoses, mainly in the crural vessels, were overgraded compared with intraarterial DSA. Particularly in patients with proximal severe obstructions or occlusions, the crural segments could be depicted more clearly due to decreased arterial runoff in conventional angiography. CONCLUSION: The consistency of the excellent depiction of the vascular territories of the distal aorta and the pelvic and lower limb arteries in a standardized setting suggests great potential for the use of MRA in the primary diagnosis of peripheral arterial occlusive disease.     

Optimizing of gadolinium-enhanced MR angiography by manipulation of acquisition and scan delay times

An optimized protocol for achieving high-quality contrast-enhanced MR angiography (CE MRA) was designed and evaluated. Time–intensity curves of the test bolus and main bolus were compared in 11 volunteers. To identify the acquisition zone sensitive to venous overprojection, sequential filling phantoms which consisted of 12 test tubes were developed and scanned. Using the parameters of the time–intensity curve which were consistent between the test and main boluses and the parameters of the sensitive acquisition zone in the pulse sequences, the protocol for calculation of scan delay time and acquisition time was optimized. The new protocol was verified by comparison of lower extremity CE MRAs acquired by traditional (scan delay time = peak enhancement time minus injection duration/2 + acquisition time/2; n = 12) and new (n = 23) protocols. The arterial and venous enhancing times of the time–intensity curves of the test and main boluses were statistically consistent (p < 0.01). The length of the sensitive acquisition zone was one-half the acquisition duration. With the parameters identified in the time–intensity curve and pulse sequence analyses, a new protocol was developed. For validation, the new protocol was able to study the smaller arteries such as the distal tibial arteries and branches of the femoral and iliac arteries (p < 0.01). Using the optimized protocol, higher-quality images were obtained than those acquired by traditional methods. Received: 29 February 2000 Revised: 1 August 2000 Accepted: 12 September 2000     

The use of below-knee percutaneous transluminal angioplasty in arterial occlusive disease causing chronic critical limb ischemia

Purpose To determine the efficacy, safety and long-term results of crural artery percutaneous transluminal angioplasty (PTA) in limbs with chronic critical limb ischemia (CLI). Methods Patients undergoing crural artery PTA due to CLI were followed at regular clinic visits with ankle brachial pressure index (ABPI) measurements. PTA of the crural arteries was attempted either alone (n=39) or in combination with PTA of the superficial and/or popliteal artery (n=55) in 86 limbs (82 patients and 94 procedures) presenting with CLI. The ages of patients ranged from 37 to 94 years (mean 72 years). The indications for PTA were rest pain in 10 and ulcer/gangrene in 84 limbs. Results A technically successful PTA with at least one crural level was achieved in 88% of cases (n=83). Cumulative primary clinical success rates at 6, 12, 24, and 36 months were 55%, 51%, 36%, and 36%, respectively. Cumulative secondary clinical success and limb salvage rates at 36 months were 44% and 72%, respectively. Conclusion PTA of the crural arteries might be considered the primary choice of treatment in patients with CLI and distal lesions with localized stenosis or segmental short occlusions.     

Transbrachial Thrombolysis,PTA and Stenting in the Lower Extremities

We present an analysis of 37 interventions in the arteries of the lower limbs via a transbrachial arterial approach. Twenty-six patients (42–79 years) underwent 37 interventional procedures in the lower extremities (iliac n = 6, iliac + femoro-popliteal n = 1, femoro-popliteal n = 30) with a vascular approach via the brachial artery (33 left sided, 4 right sided, introducer sheath 4–7 F). The transbrachial approach was chosen to avoid puncture of femoral bypass graft material. Technical success could be achieved in 11/13 thrombolyses, 8/9 PTAs, 7/10 combinations of thrombolysis and percutaneous transluminar angioplasty (PTA) and in the placement of two stents. One patient suffered from periprocedural severe re-thrombosis due to insufficient anticoagulation during fibrinolysis, and twice thrombolysis was incomplete. One puncture-related false aneurysm of the brachial artery had to be corrected surgically. One transient ischemic attack (TIA) and four minor complications occurred. Transbrachial vascular approach for arterial interventions in iliac and femoro-popliteal pathologies is a reasonable alternative to the transaxillary access if transfemoral puncture has to be avoided. The technical success rate is comparable with the results of the transaxillary and transfemoral approach. To minimize, at least theoretically, the risk of cerebral complications, the left- sided approach should be preferred and intravenous heparin should be administered routinely.     

Sequestrated thrombolysis: Comparative evaluation in vivo

Purpose: Lysis of a thrombus is a function of the local concentration of thrombolytic enzymes. This study was designed to determine in a porcine model of acute deep vein thrombosis (DVT) whether perithrombic sequestration of small volumes of a concentrated enzyme solution can accelerate the process of thrombolysis. Methods: DVT was induced in both hind limbs using a previously described technique (n = 32). Thirty minutes later the animal was heparinized and unilateral thrombolysis was attempted using 8 mg recombinant tissue plasminogen activator (rt-PA); saline was administered in the opposite leg. For conventional high-volume infusion (CI) (n = 5) rt-PA (0.067 mg/ml) was infused at 1 ml/min. For sequestrated thrombolysis the external iliac vein was endoluminally occluded, and rt-PA (0.25 mg/ml) administered either for proximal injection (ST-P) (n = 5), as a bolus every 3 min through a microcatheter placed via the balloon catheter, or for transthrombic injection (ST-T) (n = 5), as a bolus every 3 min through a Katzen wire in the balloon catheter. At autopsy, the thrombus mass in the iliofemoral veins was measured, and the extent of residual thrombosis in the venous tributaries graded at four sites. From these data a thrombolysis score was calculated. Results: One pig died before thrombolysis could be performed. Only with ST-T was residual thrombus mass in the test limb normalized to control, residual thrombus index (RTI), consistently less than unity. The median RTI of this group was 0.50 (range 0.39–0.97) compared with 1.22 (0.64–1.38) for ST-P and 0.88 (0.37–1.13) for CI. Compared with contralateral controls, a lower grade of residual thrombosis in tributaries was observed in test limbs at more venous sites with ST-T (8/20; 95% confidence interval 5–13) and ST-P (9/20; confidence interval 5–13) than with CI (2/20; confidence interval 0–5) (p= 0.04). A trend toward lower thrombolysis scores was observed with ST-T (p = 0.08). Systemic fibrinogenolysis was not observed in any of the groups. Changes in coagulation parameters during thrombolysis were similar irrespective of treatment protocol. Conclusions:“Transthrombic” sequestrated thrombolysis may offer some advantages over conventional selective infusion for the treatment of acute DVT. However further refinements will be necessary before it can be considered an alternative to the latter.     

The importance of adjusting for differences in proximal and distal contrast bolus arrival times in contrast-enhanced iliac artery magnetic resonance angiography

We tested the hypothesis that differences in proximal and distal contrast bolus arrival times may result in insufficient vascular signal in the distal part of the aortoiliofemoral territory with routinely used timing techniques. The difference in arrival time of the contrast medium bolus between the aorta and the common femoral arteries was measured in 14 patients undergoing magnetic resonance angiography of the aortoiliac arteries. A dual-station test bolus technique adjusting for this difference was evaluated. The variation coefficient of the signal intensity in six defined locations and signal intensities (SI) normalised to fat were calculated. Comparisons were made with findings in 13 patients examined with a fluoroscopically triggered timing technique (BolusTrak, Philips Medical Systems, Best, The Netherlands). The difference in bolus arrival time between proximal and distal vessels was 0–7 s. In 3 of 14 patients it was 5.6–7 s. There was a tendency towards a lower mean variation coefficient in the dual-station group (p=0.10). With both techniques, significantly lower SIs were measured in the femoral arteries compared with SIs in the superior part of the abdominal aorta. In two cases in the BolusTrak group, a distal vessel could not be delineated but was shown to be patent on a delayed scan. Differences in contrast medium arrival time along the vessel may be large enough to preclude visualisation of distal vessels unless there is compensation. A dual-station test bolus technique taking this into account was found to be feasible. Electronic Publication     

Dynamic contrast-enhanced MR angiography from the distal aorta to the ankle joint with a step-by-step technique

OBJECTIVE: The aim of this study was to visualize the arteries from the distal aorta to the ankle joint and to determine the accuracy of MR angiography for detecting stenoses and occlusions. SUBJECTS AND METHODS: Twenty-four patients with peripheral arterial occlusive disease underwent digital subtraction angiography and were examined on a 1.5-T MR scanner. The transit time for contrast material was determined with a test bolus injection. A T1-weighted three-dimensional gradient-echo sequence with short TR and TE was used for a dynamic measurement at the level of the iliac arteries, the upper leg, and the lower leg arteries. For each level a single dose of gadolinium was injected into an antecubital vein with an MR power injector. Maximal-intensity-projection reconstructions were calculated after subtraction of the first measurement at each level. Two experienced MR radiologists who were unaware of the digital subtraction angiography results interactively evaluated both the MIP reconstructions and the single slices on a workstation, first independently and then in a consensus interpretation. RESULTS: With digital subtraction angiography, 80 hemodynamically significant stenoses and 39 occlusions were detected. For the stenoses and occlusions, a sensitivity of 100% was found for MR angiography. The specificity for the assessment of stenoses and occlusions was 98% and 94%, respectively, for the iliac arteries; 98% and 94%, respectively, for the upper leg arteries; and 94% and 95%, respectively, for the lower leg arteries. Most false-positive findings of occlusion were due to metal stents present in the iliac (n = 3) and upper leg (n = 4) arteries. CONCLUSION: The MR imaging technique that we used revealed the arteries from the distal aorta to the ankle and proved to be reliable at showing arterial stenoses and occlusions.     

Optimized diagnostic angiography in high-risk patients with severe peripheral vascular disease.

Conventional arteriography remains the usual method for preoperative assessment of severe peripheral vascular disease (PVD). Unfortunately, many peripheral arteriograms are still performed with a suboptimal technique, which can cause significant diagnostic errors in patients with severe PVD. A suboptimal technique may be due to poor collimation (causing incorrect exposure and incorrect gray scale), excessive patient-film distance (magnification unsharpness), inadequate volume or density of contrast material, poor contrast resolution (screen-film arteriography), nonselective injection, patient movement, and pressure from restraints or incorrect patient position (failure to profile lesions, pseudo-occlusion from external pressure or plantar flexion). The technique of selective digital subtraction arteriography (DSA) allows one to avoid these errors. The superior contrast resolution of DSA allows use of lower concentrations of contrast material. Selective injection into the external iliac artery allows proper positioning and improves image quality. Demonstration of distal vessels is best achieved by using biplane arteriography. For patients with severe resting ischemia, especially those with diabetes, high-quality selective DSA is essential to ensure that all distal vessels suitable for distal bypass grafting are identified. When properly performed, selective DSA remains the investigation of choice for reliably demonstrating arterial anatomy in high-risk patients with severe PVD.     

Low contrast volume run-off CT angiography with optimized scan time based on double-level test bolus technique – feasibility study

Purpose

To verify the technical feasibility of low contrast volume (40 mL) run-off CT angiography (run-off CTA) with the individual scan time optimization based on double-level test bolus technique.

Materials and methods

A prospective study of 92 consecutive patients who underwent run-off CTA performed with 40 mL of contrast medium (injection rate of 6 mL/s) and optimized scan times on a second generation of dual-source CT. Individual optimized scan times were calculated from aortopopliteal transit times obtained on the basis of double-level test bolus technique – the single injection of 10 mL test bolus and dynamic acquisitions in two levels (abdominal aorta and popliteal arteries). Intraluminal attenuation (HU) was measured in 6 levels (aorta, iliac, femoral and popliteal arteries, middle and distal lower-legs) and subjective quality (3-point score) was assessed. Relations of image quality, test bolus parameters and arterial circulation involvement were analyzed.

Results

High mean attenuation (HU) values (468; 437; 442; 440; 342; 274) and quality score in all monitored levels was achieved. In 91 patients (0.99) the sufficient diagnostic quality (score 1–2) in aorta, iliac and femoral arteries was determined. A total of 6 patients (0.07) were not evaluable in distal lower-legs. Only the weak indirect correlation of image quality and test-bolus parameters was proved in iliac, femoral and popliteal levels (r values: −0.263, −0.298 and −0.254). The statistically significant difference of the test-bolus parameters and image quality was proved in patients with occlusive and aneurysmal disease.

Conclusion

We proved the technical feasibility and sufficient quality of run-off CTA with low volume of contrast medium and optimized scan time according to aortopopliteal transit time calculated from double-level test bolus.     

Contrast enhanced MRA of peripheral arteries with the automatic "floating table".

Magnetic resonance angiography (MRA) is increasingly used as a non-invasive alternative to digital subtraction angiography (DSA). Besides plain time-of-flight (TOF) and phase contrast (PC) MRA a new MRA technique using positive contrast agent has been introduced recently. A fast 3D gradient-echo sequence is applied to reach a significant reduction of measurement time for acquisition of the MRA within the first pass of the contrast agent, thereby avoiding venous overlap. A significant progress was yielded by MR systems allowing manual table movement for examination of the pelvis and the lower limbs in one examination with a single contrast agent bolus. However, in this case it is necessary to have a coworker in the examination room moving the table manually. In this paper we report a prototype system which allows automatic table movement ("floating table"). Using this novel system we examined a patient with an aneurysm of the abdominal aorta and peripheral arterial occlusive disease (PAOD). Diagnostic results of contrast enhanced MRA and DSA were equivalent. In summary, the automatic floating table system introduced in this paper allows comfortable non-invasive examination of pelvic and lower limb arteries. The value of this technique in comparison to DSA has to be determined in future studies.     

下肢动脉阻塞性病变的DSA成像探讨

目的：探讨下肢动脉阻塞性病变的ＤＳＡ成像特性。方法：对６７例中的５６例下肢动脉阻塞性病变的ＤＳＡ成像进行分析,采用常规造影剂量与加大造影剂量比较,髂外动脉与股动脉造影比较及曝光延时的比较。结果：正常１１例,病变５６例,双侧病变１０例。加大造影剂量,股动脉注药及特殊曝光延时,使用准确的延迟时间,可提高阻塞病变远端血管和侧支循环的显示率。     

Gravity large field phlebography of the limbs

For the last two decades the most common method of radiographic study of the venous system of the lower limbs has been ascending phlebography, by injection of contrast material in a superficial vein on the dorsum of the foot. We report our own experience with another approach, using a large field technique on recumbent patients, with elevation of the limbs, thus taking advantage of gravity. The contrast injection is usually made in a more distal superficial vein of the foot after a tiny cut-down. Excellent results are consistently obtained in demonstrating all the deep veins, including the iliac vessels. The same principles may be applied to upper limb phlebography.     

旋转DSA的临床应用

目的　评价旋转DSA的临床应用价值。方法　采用PHILIPSV5 0 0 0数字成像系统 ,对 3 0例患者实施旋转式数字减影血管造影 48例次。其中脑动脉 8例 ,颈动脉 2例 ,四肢动脉 7例 ,肝动脉 2例 ,肺动脉 1例 ,髂动脉 2例 ,腹主动脉 1例 ,肾动脉 2例以及子宫动脉 5例。结果　 3 0例患者 2 8例良好地显示了病变处血管起源、走行、分布、数目、轮廓以及假性动脉瘤的瘘口。结论　旋转式数字减影血管造影能够清楚显示所检查部位的血管结构 ,对病变的术前诊断和制定手术计划具有重要的参考价值。     

Gadolinium dimeglumine: an alternative contrast agent for digital subtraction angiography

The aim of this study was to evaluate gadolinium diethylenetriaminepenta-acetic acid (Gd-DTPA) as an alternative contrast agent for digital subtraction angiography (DSA) in patients with renal insufficiency or previous anaphylactic reaction to iodinated contrast agents. We performed 34 DSAs in 31 patients by use of the commercially available 0.5-M Gd-DTPA solution (Magnevist, Schering, Berlin, Germany). The contrast material was power- or hand-injected at the same rate as iodinated contrast material, without exceeding a total amount of 0.4 mmol/kg body weight. In 18 studies Gd-DTPA was the sole contrast agent. In 9 cases gadolinium injections were combined with carbon dioxide. Restricted non-ionic contrast medium injections were administered to complete the examinations in 7 cases and for comparative purposes in 1 case. Cerebral and carotid arteries, one superior limb, abdominal aorta, renal arteries, renal transplants, iliac arteries and inferior limbs were imaged, and ten endovascular interventional procedures, including three transjugular intrahepatic percutaneous stent shunts, were performed. No side effects were observed. Diagnostic angiographic images were obtained in all cases except in 5 of the 8 distal run-off studies. Gadolinium-based contrast can produce clinically useful angiograms in patients with a contra-indication to iodine who must undergo angiography. Received: 15 April 1998; Revision received: 2 July 1998; Accepted: 25 July 1998     

Intravenous contrast material administration at high-pitch dual-source CT pulmonary angiography: test bolus versus bolus-tracking technique

Purpose

To compare test bolus and bolus tracking for the determination of scan delay of high-pitch dual-source CT pulmonary angiography in patients with suspected pulmonary embolism using 50 ml of contrast material.

Materials and methods

Data of 80 consecutive patients referred for CT pulmonary angiography were evaluated. All scans were performed on a 128-channel dual-source CT scanner with a high-pitch protocol (pitch 3.0, 100 kV, 180 mA s). Contrast enhancement was achieved by injecting 50 ml of iomeprol followed by a saline chaser of 50 ml injected at a rate of 4 ml/s. The scan delay was determined using either the test bolus (n = 40) or bolus tracking (n = 40) technique. Test bolus required another 15 ml CM to determine time to peak enhancement of the contrast bolus within the pulmonary trunk. Attenuation profiles in the pulmonary trunk and on segmental level as well as in the ascending aorta were measured to evaluate the timing techniques. Additionally, overall image quality was evaluated.

Results

In all patients an adequate and homogeneous contrast enhancement of more than 250 HU was achieved in the pulmonary arteries. No statistically significant difference between test bolus and bolus tracking was found regarding attenuation of the pulmonary arteries or overall image quality. However, using bolus tracking 15 ml CM less was injected.

Conclusion

A homogeneous opacification of the pulmonary arteries and sufficient image quality can be achieved with both the bolus tracking and test bolus techniques with significant lower contrast doses compared to conventional contrast material injection protocols.     

Long-Term Follow-Up After Endovascular Treatment of Acute Aortic Emergencies

Purpose To investigate the long-term outcome and efficacy of emergency treatment of acute aortic diseases with endovascular stent-grafts. Methods From September 1995 to April 2007, 37 patients (21 men, 16 women; age 53.9 ± 19.2 years, range 18–85 years) with acute complications of diseases of the descending thoracic aorta were treated by endovascular stent-grafts: traumatic aortic ruptures (n = 9), aortobronchial fistulas due to penetrating ulcer or hematothorax (n = 6), acute type B dissections with aortic wall hematoma, penetration, or ischemia (n = 13), and symptomatic aneurysm of the thoracic aorta (n = 9) with pain, penetration, or rupture. Diagnosis was confirmed by contrast-enhanced CT. Multiplanar reformations were used for measurement of the landing zones of the stent-grafts. Stent-grafts were inserted via femoral or iliac cut-down. Two procedures required aortofemoral bypass grafting prior to stent-grafting due to extensive arteriosclerotic stenosis of the iliac arteries. In this case the bypass graft was used for introduction of the stent-graft. Results A total of 46 stent-grafts were implanted: Vanguard/Stentor (n = 4), Talent (n = 31), and Valiant (n = 11). Stent-graft extension was necessary in 7 cases. In 3 cases primary graft extension was done during the initial procedure (in 1 case due to distal migration of the graft during stent release, in 2 cases due to the total length of the aortic aneurysm). In 4 cases secondary graft extensions were performed—for new aortic ulcers at the proximal stent struts (after 5 days) and distal to the graft (after 8 months) and recurrent aortobronchial fistulas 5 months and 9 years after the initial procedure—resulting in a total of 41 endovascular procedures. The 30-day mortality rate was 8% (3 of 37) and the overall follow-up was 29.9 ± 36.6 months (range 0–139 months). All patients with traumatic ruptures demonstrated an immediate sealing of bleeding. Patients with aortobronchial fistulas also demonstrated a satisfactory follow-up despite the necessity for reintervention and graft extension in 3 of 6 cases (50%). Two patients with type B dissection died due to mesenteric ischemia despite sufficient mesenteric blood flow being restored (but too late). Two suffered from neurologic complications, 1 from paraplegia and 1 from cerebral ischemia (probably embolic), 1 from penetrating ulcer, and 1 from persistent ischemia of the kidney. Five of 9 (56%) patients with symptomatic thoracic aneurysm demonstrated endoleaks during follow-up and there was an increase in the aneurysm in 1. Conclusion Endovascular treatment is safe and effective for emergency treatment of life-threatening acute thoracic aortic syndromes. Results are encouraging, particularly for traumatic aortic ruptures. However, regular follow-up is mandatory, particularly in the other pathologies, to identify late complications of the stent-graft and to perform appropriate additional corrections as required.     

A simple angiographic method for assessing aorto-femoral bypass grafts

Direct puncture of femoral bypass grafts in the groin with retrograde injection of contrast was employed to assess the lower abdominal aorta, iliac and lower limb arteries. The technique was effective, simple, quick and safe.     

Urgent thoracic aortal dissection and aneurysm: treatment with stent-graft implantation in an angiographic suite

The aim of this study was to evaluate the feasibility of endoluminal stent-graft placement in an angiographic suite for the treatment of emergent type-B aortic dissections and ruptured thoracic aortal aneurysms. Twenty-six patients with either urgent type-B dissection (n=8) or aneurysms (n=18) of the descending thoracic aorta were chosen for stent-graft implantation. All patients received a multidetector-row CT angiography of the whole aorta and pelvic arteries prior to stent-graft implantation. All procedures were performed in a fully equipped digital subtraction angiography (DSA) suite under general anesthesia. In 20 patients Talent LPS tube grafts and in 4 patients an Excluder graft were used. Access was achieved via surgical cut-down in the left (n=7) or right (n=19) groin. Sealing was successful in 24 patients. The proximal covered portion of the stent graft was placed across the left subclavian artery in 2 patients. Procedural success was achieved in 23 of 24 patients. One patient required a second stent-graft placement before the aneurysm was sealed. One patient with an acute perforation of the descending aorta died due to cardiac failure prior to stent-graft implantation. In 1 patient stent-graft delivery failed due to severe calcification of both common iliac arteries. Endoluminal treatment of both urgent type-B aortic dissections and thoracic aortal aneurysms with stent graft is an attractive alternative treatment to surgical repair. The placement of stent grafts in an angiographic suite is a safe and feasible method with good clinical effectiveness and, so far, good clinical outcome.     

Absolute renal blood flow quantification by dynamic MRI and Gd-DTPA

The aim of this study was to demonstrate the feasibility of the absolute renal blood flow quantification using MRI and injection of contrast media. Using a T1-weighted fast gradient sequence following an intravenous bolus injection of Gd-DTPA, dynamic images of the kidney were obtained in patients with well-functioning native kidneys (n = 7) or transplant (n = 9), with significant renal artery stenosis (n = 4) and with renal failure (n = 7). After signal intensity calibration, the absolute renal perfusion was equal to the wash-in slope of the renal transit curve divided by the contrast medium concentration at the peak of the bolus in the aorta. The cortical blood flow was 2.54 ± 1.16 ml/min per gram in well-functioning kidneys decreasing to 1.09 ± 0.75 ml/min per gram in case of renal artery stenosis (p = 0.04) and to 0.51 ± 0.34 ml/min per gram in case of renal failure (p < 0.001). These measurements were in agreement with previous results obtained by other methods. A standard MRI imaging sequence and a simple model can provide realistic quantitative data on renal perfusion. This work justifies further studies to compare this model with a gold standard for renal blood flow measurements. Received: 9 September 1999; Revised: 31 January 2000; Accepted: 16 March 2000