Use of magnetic resonance angiography for the preoperative evaluation of patients with infrainguinal arterial occlusive disease

Purpose: This study was designed to determine whether magnetic resonance angiography (MRA) will allow preoperative management decisions without the need for contrast arteriography in patients with lower extremity ischemia caused by infrainguinal arterial occlusive disease.Methods: Forty-five patients with lower extremity ischemia in 50 limbs were evaluated by both two-dimensional time-of-flight MRA and intraarterial digital subtraction angiography (DSA) between February 1992 and June 1995. Independent management plans were based on clinical presentation, pulse volume recordings, and separate reviews of the MRA and DSA.Results: Of 50 limbs, 23 required arterial bypass, 19 percutaneous transluminal angioplasty, 5 patch angioplasty, and 3 amputation. MRA and DSA correlated exactly in 89.5% of infrainguinal arterial segments, whereas interpretations disagreed in 10.5% of arterial segments. Mismatches that had an influence on patient treatment decisions occurred in only 8 (2.3%) of 352 arterial segments. Independent MRA- and DSA-based revascularization plans agreed in 45 (90%) extremities. MRA predicted the level of arterial reconstruction in all 23 limbs that required arterial bypass. MRA identified focal stenoses amenable to percutaneous transluminal angioplasty in 18 (94.7%) of the 19 limbs that ultimately underwent percutaneous transluminal angioplasty. A strategy of preoperative planning by MRA with confirmatory intraoperative arteriography would represent a 31% cost savings per patient at our institution while eliminating the morbidity of preoperative DSA.Conclusions: When used in combination with the patient's physical examination and segmental limb pressures with plethysmography, MRA is sufficient for planning infrainguinal arterial bypass procedures and selecting patients for percutaneous transluminal angioplasty. (J Vasc Surg 1996;23:792-801.)     

Comparison of treatment plans for lower extremity arterial occlusive disease made with electrocardiography-triggered two-dimensional time-of-flight magnetic resonance angiography and digital subtraction angiography.

BACKGROUND: The purpose of the study was to determine whether preoperative treatment plans for patients with lower extremity ischemia can be made with electrocardiography (EKG)-triggered two-dimensional (2D) time-of-flight (TOF) magnetic resonance angiography (MRA) as accurately as digital subtraction angiography (DSA). METHODS: Forty patients were prospectively evaluated with the combination of EKG-triggered 2D TOF MRA, DSA, and pulse volume recordings. Blinded reviewers graded arterial segments for disease severity. Accuracy of separate MRA- and DSA-based treatment plans was compared with the procedures performed based on all available information. RESULTS: There was an 86% exact match between MRA- and DSA-based plans (92% MRA and 94% DSA accuracy). The MRA-based plan accurately predicted 90% of suprainguinal and 95% of infrainguinal procedures, whereas the DSA-based plan accurately predicted 100% of suprainguinal and 85% of infrainguinal procedures. Two-year primary patency was 83% for all procedures. Radiologists' review of disease severity resulted in a mean exact correlation between studies of 81% (kappa = 0.64). The agreement between radiologists interpreting the MRA was 84% (kappa = 0.7) compared with 82% (kappa = 0.66) for the DSA. CONCLUSIONS: MRA- and DSA-based preoperative management plans were of comparable efficacy. Significant interobserver variability was seen with the interpretations of both preoperative studies. EKG-triggered 2D TOF MRA can be used to plan arterial reconstructions; however, all patients require arterial pressure measurements prior to suprainguinal repair and confirmatory intraoperative angiography during infrainguinal revascularization.     

Assessment of Moyamoya disease with 3.0-T magnetic resonance angiography and magnetic resonance imaging versus conventional angiography

3.0-T magnetic resonance (MR) angiography and MR imaging were compared with conventional angiography for the evaluation of moyamoya disease in 13 preoperative patients (26 hemispheres) with moyamoya disease (4 males and 9 females aged 21-54 years). The correlation between MR angiography scores determined by modified Houkin's grading system (MRA score) and conventional angiography stages determined by Suzuki's grading system (CA stage) was analyzed. Other MR findings such as moyamoya vessel scores, "ivy sign" scores, and the presence of small, medium, and large cerebrovascular attack (CVA) lesions were compared with CA stages. MRA scores were significantly correlated with CA stages (p < 0.01). Moyamoya vessel scores correlated well with CA stages (p < 0.01). There was no significant correlation between "ivy sign" scores and CA stages, and no significant differences in CA stages with the presence and absence of CVA lesions of any size. 3.0-T MR angiography can be used as a vascular assessment in moyamoya disease with its priority of noninvasive nature and visual clarity compared with conventional angiography. The findings of 3.0-T MR angiography may reflect the steno-occlusive changes in moyamoya disease.     

Clinical utility of diffusion-weighted magnetic resonance imaging in prostate cancer

Study Type – Diagnostic (exploratory cohort) Level of Evidence 2b What’s known on the subject? and What does the study add? This article reviews what is currently known about diffusion weighted MRI (DW‐MRI) in prostate cancer. This mini‐review concisely summarises, for clinical managing patients with prostate cancer, the clinical utility of diffusion weighted MRI.

OBJECTIVE

? To review the clinical utility of diffusion‐weighted magnetic resonance imaging (DW‐MRI) in patients with prostate cancer.

MATERIAL AND METHODS

? The current literature on prostate cancer and DW‐MRI was reviewed.

RESULTS

? DW‐MRI can be readily acquired on a modern scanner with a short image acquisition time and no need for i.v. contrast medium. ? The image contrast is based on the diffusion of water molecules and thus reflects tissue cellularity. ? There is increasing evidence that DW‐ MRI improves the sensitivity and specificity of prostate cancer detection as well as the identification of tumour aggressiveness. ? DW‐MRI is also showing substantial promise as a response biomarker for both local and metastatic disease

CONCLUSIONS

? DW‐MRI is proving to be a useful adjunct to conventional T2‐weighted MRI sequences. ? The eventual role of DW‐MRI in combination with other MRI techniques for multiparametric assessment of prostate cancer needs to be defined further.     

Comparison of treatment plans for peripheral arterial disease made with multi-station contrast medium-enhanced magnetic resonance angiography and duplex ultrasound scanning

OBJECTIVE: This study was undertaken to investigate the effects of substituting multi-station total outflow contrast medium-enhanced magnetic resonance angiography (CE-MRA) for color duplex ultrasound (US) scanning on treatment planning in the diagnostic workup of patients with suspected or known peripheral arterial occlusive disease.Patients and methods One hundred consecutive patients referred because of suspected or proved peripheral arterial occlusive disease to a University Hospital underwent both aortoiliac duplex US scanning and multi-station total outflow CE-MRA. For 73 of these patients (57% men; mean age, 62 years) treatment or treatment plans could be retraced. Eighteen patients also underwent femoro-popliteal duplex US scanning. Three experienced vascular surgeons retrospectively formulated two sets of treatment plans based on standardized clinical parameters and either duplex US scanning or CE-MRA. The main outcome measure was proportion of patients for whom the treatment plan matched actual treatment without additional use of intra-arterial digital subtraction angiography. Actual treatment, based on all available information, including results of duplex US scanning, CE-MRA, and any other diagnostic tests, served as the standard of reference. RESULTS: Duplex US scanning provided enough information for treatment planning in 46, 45, and 53 patients versus 67, 68, and 66 patients when CE-MRA was used (surgeons 1, 2, and 3, respectively; surgeons 1 and 2, P <.001; surgeon 3, P =.007). Treatment plans based on duplex US scanning exactly matched actual treatment in 37 of 73 patients (51%; surgeon 1), 36 of 73 patients (49%; surgeon 2), and 46 of 73 patients (63%; surgeon 3). Treatment plans based on CE-MRA exactly matched actual treatment in 56 of 73 patients (77%; surgeon 1), 55 of 73 patients (75%; surgeon 2), and 51 of 73 patients (70%; surgeon 3). Positive predictive value and negative predictive value of duplex US scanning as measures of ability to discriminate between surgical and nonsurgical treatment were 0 of 0 (undefined) and 43 of 46 (93%), 1 of 2 (50%) and 40 of 43 (93%), and 5 of 5 (100%) and 44 of 48 (92%) for surgeons 1, 2, and 3, respectively. For CE-MRA, positive and negative predictive values were 11 of 13 (85%) and 50 of 54 (93%), 10 of 12 (83%) and 51 of 56 (91%), and 8 of 13 (62%) and 48 of 53 (91%), respectively, for surgeons 1, 2, and 3. CONCLUSION: Compared with aorto-iliac and femoro-popliteal duplex US scanning, multi-station total outflow CE-MRA is more effective for treatment planning in most patients with known or suspected peripheral arterial occlusive disease.     

3-D magnetic resonance angiography versus conventional angiography in peripheral arterial disease: pilot study

BACKGROUND: Angiography is usually performed as the preoperative road map for those requiring revascularization for lower extremity peripheral arterial disease (PAD). The alternative investigations are ultrasound, 3-D magnetic resonance angiography (3-D MRA) and computed tomography angiography. This pilot study aimed to assess whether 3-D MRA could replace the gold standard angiography in preoperative planning. METHODS: Eight patients considered for aortoiliac or infrainguinal arterial bypass surgery were recruited. All underwent both imaging modalities within 7 days. A vascular surgeon and a radiologist each reported on the images from both the 3-D MRA and the angiography, with blinding to patient details and each others reports. Comparisons were made between the reports for the angiographic and the 3-D MRA images, and between the reports of the vascular surgeon and the radiologist. RESULTS: Compared to the gold standard angiogram, 3-D MRA had a sensitivity of 77% and specificity of 94% in detecting occlusion, and a sensitivity of 72% and specificity of 90% in differentiating high grade (>50%) versus low grade (<50%) stenoses. There was an overall concordance of 78% between the two investigations with a range of 62% in the peroneal artery to 94% in the aorta. 3-D MRA showed flow in 23% of cases where conventional angiography showed no flow. CONCLUSIONS: In the present pilot study, 3-D MRA had reasonable concordance with the gold standard angiography, depending on the level of the lesion. At times it showed vessel flow where occlusion was shown on conventional angiogram. 3-D MRA in peripheral vascular disease is challenging the gold standard, but is inconsistent at present.     

Fusion of magnetic resonance angiography and magnetic resonance imaging for surgical planning for meningioma--technical note

A fusion technique for magnetic resonance (MR) angiography and MR imaging was developed to help assess the peritumoral angioarchitecture during surgical planning for meningioma. Three-dimensional time-of-flight (3D-TOF) and 3D-spoiled gradient recalled (SPGR) datasets were obtained from 10 patients with intracranial meningioma, and fused using newly developed volume registration and visualization software. Maximum intensity projection (MIP) images from 3D-TOF MR angiography and axial SPGR MR imaging were displayed at the same time on the monitor. Selecting a vessel on the real-time MIP image indicated the corresponding points on the axial image automatically. Fusion images showed displacement of the anterior cerebral or middle cerebral artery in 7 patients and encasement of the anterior cerebral arteries in 1 patient, with no relationship between the main arterial trunk and tumor in 2 patients. Fusion of MR angiography and MR imaging can clarify relationships between the intracranial vasculature and meningioma, and may be helpful for surgical planning for meningioma.     

Color Doppler imaging of infrainguinal arterial occlusive disease.

Few reports in the literature validate the use of color Doppler imaging (CDI) for the evaluation of lower extremity arterial occlusive disease, particularly in the tibial and peroneal arteries. This prospective, blinded study compares CDI to arteriography to address the following questions: (1) how well does CDI visualize arterial segments, including those below the knee? and (2) can CDI alone accurately classify the degree of occlusive disease? Twenty-nine men undergoing arteriography before a lower extremity arterial reconstructive procedure were studied with a color ultrasound scanner from the level of the inguinal ligament to the ankle. Color images were examined for the presence or absence of triphasic flow, poststenotic turbulence, color bruits, and collateral vessels. Among 636 arterial segments adequately visualized by arteriography, > or = 90% were identified with color Doppler imaging, including the tibial and peroneal arteries. With color criteria only, specificity was > or = 92% for distinguishing < 50% from > = 50% lesions and > or = 93% for differentiating patent from occluded arteries. Sensitivity for detecting an occlusion was > or = 97% in the superficial femoral (SFA) and popliteal arteries and 83% in the tibial vessels. For identifying a > or = 50% stenosis, sensitivity was > or = 85% in the SFA and popliteal arteries but only 79% and 86% in the posterior and anterior tibial arteries, respectively. CDI reliably identifies vessel location from the level of the groin to the ankle. For the detection of occlusions, CDI is an accurate screening tool in the SFA and popliteal arteries but is less accurate in the tibial vessels.(ABSTRACT TRUNCATED AT 250 WORDS)     

Multi-detector row computed tomography angiography: an alternative imaging method for surgical strategy in lower extremity arterial occlusive disease

In order to show the value of CT angiography in the pretherapeutic assessment of lower leg ischemia, we studied 93 CT angiographies in 85 patients. Two groups were defined according to the level of revascularization: 52 angioscanner were made prior to suprainguinal revascularization and 41 prior to infrainguinal reconstruction. Two decision attitudes were chosen by two different physicians, a radiologist and vascular surgeon, members of the same team. The attitudes where then compared in order to evaluate the value of CT angiography. The first attitude was a pragmatic strategy based on the images as interpreted by the first physician and on the intraoperative information including surgical treatment and, if necessary, angiography. This indicates that the results of this attitude cover the performed revascularizations. The second attitude determined a virtual strategy and was chosen by the second physician a posteriori, based solely on the medical file with the same CT angiography images. These two strategies were compared in order to assess the agreement on the level of the lesion and the choice of revascularization. In 84 CT angiographies (90.3%), the analysis of the lesions and the choice of lesions to be treated were identical. In 9.6% of scans the strategies were not comparable because the lesions were interpreted differently or the scans were difficult to read. The sensitivity of CT angiography in detecting lesions and guiding the therapeutic strategy was 96% and its positive predictive value was 93%. Follow-up was reported according to the life-table method to assess the overall outcome and the results in both groups. The overall survival rate at 12 months for 85 patients was 90%. Secondary patency rates at 12 months in the group of patients who underwent a suprainguinal and infrainguinal revascularization were 98% and 71% respectively. Overall limb salvage at 12 months was 94%. In this setting, CT angiography allowed us to select adequate treatment in the majority of cases. These results obtained after a strategy based on CT angiography images are comparable with the results as published in the literature after the strategy based on conventional angiography.     

Three-dimensional magnetic resonance imaging based on time-of-flight magnetic resonance angiography for superficial cerebral arteriovenous malformation--technical note

Direct surgery remains important for the treatment of superficial cerebral arteriovenous malformation (AVM). Surgical planning on the basis of careful analysis from various neuroimaging modalities can aid in resection of superficial AVM with favorable outcome. Three-dimensional (3D) magnetic resonance (MR) imaging reconstructed from time-of-flight (TOF) MR angiography was developed as an adjunctive tool for surgical planning of superficial AVM. 3-T TOF MR imaging without contrast medium was performed preoperatively in patients with superficial AVM. The images were imported into OsiriX imaging software and the 3D reconstructed MR image was produced using the volume rendering method. This 3D MR image could clearly visualize the surface angioarchitecture of the AVM with the surrounding brain on a single image, and clarified feeding arteries including draining veins and the relationship with sulci or fissures surrounding the nidus. 3D MR image of the whole AVM angioarchitecture was also displayed by skeletonization of the surrounding brain. Preoperative 3D MR image corresponded to the intraoperative view. Feeders on the brain surface were easily confirmed and obliterated during surgery, with the aid of the 3D MR images. 3D MR imaging for surgical planning of superficial AVM is simple and noninvasive to perform, enhances intraoperative orientation, and is helpful for successful resection.     

Cardiac magnetic resonance imaging (MRI)

TECHNOLOGICAL PROGRESS: Although cardiac magnetic resonance imaging (MRI) is now recognised as the imaging method of choice for the morphological study of the heart, recent technological progress have widened its indications to functional analysis of the heart rate, perfusion and contractility. FUNCTIONAL ASSESSMENT: The possibility of conducting pharmacological stress tests enhances the functional exploration of cardiac perfusion and contractility. The rapid sequences in apnea, tissue marking and injection of contrast products are all elements that help to refine the study of the locoregional consequences of an ischemia: does the myocardial tissue contract normally? Is it sufficiently perfused? Is it still viable? THE BENEFITS OF A NON-INVASIVE TECHNIQUE: The MRI offers clinicians a non-invasive and non-radiating imaging technique that is the perfect supplement to echocardiography. A reliable angio-coronary LRI technique would, for the first time, permit exploration of the coronary vascularisation, tissue perfusion and resulting contractility.     

Fast magnetic resonance imaging with contrast for soft tissue sarcoma viability

Because dynamic (fast) contrast-enhanced magnetic resonance imaging with its temporal resolution allows evaluation of contrast kinetics of soft tissue sarcomas, its efficacy for defining viable tumor in these neoplasms was studied for three applications: biopsy localization, chemotherapeutic response, and differentiation between recurrence and inflammation after treatment. After conventional T1-weighted and T2-weighted magnetic resonance sequences to localize the lesion, patients had dynamic contrast-enhanced magnetic resonance imaging with fast and ultrafast sequences and postprocessing techniques (subtraction, time-intensity curves, and parametric color-encoding). In 10 of 40 patients, dynamic imaging more precisely defined the most malignant foci of tumor for biopsy than conventional magnetic resonance imaging. After chemotherapy, dynamic imaging distinguished 11 good responders from 21 poor responders. In followup of 196 patients, dynamic imaging detected 42 early enhancing recurrences and excluded recurrent tumor in six late enhancing pseudotumors. Dynamic imaging can differentiate viable tumor from nonviable tumor and inflammation by showing two temporally different phases of contrast enhancement: an early phase correlative with viable tumor at histologic examination, and a late phase when all tissues enhance simultaneously and may be indistinguishable. By showing tumor viability, dynamic contrast-enhanced magnetic resonance imaging can help define biopsy sites, chemotherapeutic response, and presence or absence of recurrences and therefore affect the initial evaluation, treatment, and followup of patients with soft tissue sarcomas.     

Clinical value of magnetic resonance imaging for cervical myelopathy

The magnetic resonance imaging (MRI) findings in 115 cases of cervical myelopathy, 121 cases of cervical radiculopathy, and 64 cases of neck pain with no neurologic deficit were prospectively studied to investigate the clinical value of MRI for cervical myelopathy. The MRI findings in the T1-weighted sagittal projection were classified into four groups according to the degree of the compressed deformities of the cervical cord. The degree of compression of the cervical cord on MRI findings showed a significant correlation with the severity of myelopathy, the anteroposterior diameter of the spinal column, and the degree of compression of the dural tube in the myelograms (P less than 0.01). Fifty-one patients of cervical myelopathy had undergone both preoperative and postoperative MRI. Of these, the spinal canal of 47 patients that was well decompressed was recognized according to plain computed tomography (CT). However, 24 (51%) of these 47 patients showed on MRI a deformity in the spinal cord amounting to cord atrophy. The correlation between the clinical function of the spinal cord and the recovery of the cord deformity on MRI at the operative levels was accurately investigated in 34 patients who had no cord deformities in the adjacent intervertebral levels. Twenty patients with cord atrophy had slightly poor clinical results, although no significant difference was found between these 20 and 14 patients with recovery in the cord deformities. From these results, it was evident that T1-weighted MRI is useful in the accurate diagnosis of compression myelopathy, in accurately deciding the level of the disease focus, and in the accurate assessment of the surgical results.