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MR Angiography after Renal Revascularization: Spectrum of Expected Anatomic Results and Postintervention Complications¹

¹ From the Departments of Radiology (R.C.C., Q.D., M.R.P.) and Surgery (J.C.S.), University of Michigan, 1500 E Medical Center Dr, Ann Arbor, MI 48109-0030. Presented as a scientific exhibit at the 1998 RSNA scientific assembly. Received March 12, 1999; revision requested April 13 and received June 15; accepted June 21. Supported in part by the Robert Wood Johnson Clinical Scholars Program and the Whitaker Foundation. Address reprint requests to R.C.C.

View larger version (134K): [in a new window]   Figure 1a.   Bilateral renal artery stenosis in a 65-year-old woman. (a) Coronal gadolinium-enhanced MR angiogram shows bilateral renal artery stenosis (arrows). (b) Axial 3D PC image shows signal dropout (arrows), which indicates hemodynamic significance (1). (c) Axial PC image obtained after bilateral percutaneous angioplasty shows diminished spin dephasing, which is consistent with improved flow to the kidneys. (d-f) Coronal (d) and axial (e, f) subvolume MIP images obtained after renal artery revascularization show increased caliber of both renal arteries. Minimal residual narrowing of the left renal artery origin is seen (d, f); however, the PC image (f) shows no residual spin dephasing to suggest hemodynamic significance. The postrevascularization gadolinium-enhanced MR angiography volume (d) was acquired with a longer delay after contrast material infusion, which accounts for the better visualization of the left renal vein (L) and portal vein (P).

View larger version (61K): [in a new window]   Figure 1b.   Bilateral renal artery stenosis in a 65-year-old woman. (a) Coronal gadolinium-enhanced MR angiogram shows bilateral renal artery stenosis (arrows). (b) Axial 3D PC image shows signal dropout (arrows), which indicates hemodynamic significance (1). (c) Axial PC image obtained after bilateral percutaneous angioplasty shows diminished spin dephasing, which is consistent with improved flow to the kidneys. (d-f) Coronal (d) and axial (e, f) subvolume MIP images obtained after renal artery revascularization show increased caliber of both renal arteries. Minimal residual narrowing of the left renal artery origin is seen (d, f); however, the PC image (f) shows no residual spin dephasing to suggest hemodynamic significance. The postrevascularization gadolinium-enhanced MR angiography volume (d) was acquired with a longer delay after contrast material infusion, which accounts for the better visualization of the left renal vein (L) and portal vein (P).

View larger version (64K): [in a new window]   Figure 1c.   Bilateral renal artery stenosis in a 65-year-old woman. (a) Coronal gadolinium-enhanced MR angiogram shows bilateral renal artery stenosis (arrows). (b) Axial 3D PC image shows signal dropout (arrows), which indicates hemodynamic significance (1). (c) Axial PC image obtained after bilateral percutaneous angioplasty shows diminished spin dephasing, which is consistent with improved flow to the kidneys. (d-f) Coronal (d) and axial (e, f) subvolume MIP images obtained after renal artery revascularization show increased caliber of both renal arteries. Minimal residual narrowing of the left renal artery origin is seen (d, f); however, the PC image (f) shows no residual spin dephasing to suggest hemodynamic significance. The postrevascularization gadolinium-enhanced MR angiography volume (d) was acquired with a longer delay after contrast material infusion, which accounts for the better visualization of the left renal vein (L) and portal vein (P).

View larger version (139K): [in a new window]   Figure 1d.   Bilateral renal artery stenosis in a 65-year-old woman. (a) Coronal gadolinium-enhanced MR angiogram shows bilateral renal artery stenosis (arrows). (b) Axial 3D PC image shows signal dropout (arrows), which indicates hemodynamic significance (1). (c) Axial PC image obtained after bilateral percutaneous angioplasty shows diminished spin dephasing, which is consistent with improved flow to the kidneys. (d-f) Coronal (d) and axial (e, f) subvolume MIP images obtained after renal artery revascularization show increased caliber of both renal arteries. Minimal residual narrowing of the left renal artery origin is seen (d, f); however, the PC image (f) shows no residual spin dephasing to suggest hemodynamic significance. The postrevascularization gadolinium-enhanced MR angiography volume (d) was acquired with a longer delay after contrast material infusion, which accounts for the better visualization of the left renal vein (L) and portal vein (P).

View larger version (67K): [in a new window]   Figure 1e.   Bilateral renal artery stenosis in a 65-year-old woman. (a) Coronal gadolinium-enhanced MR angiogram shows bilateral renal artery stenosis (arrows). (b) Axial 3D PC image shows signal dropout (arrows), which indicates hemodynamic significance (1). (c) Axial PC image obtained after bilateral percutaneous angioplasty shows diminished spin dephasing, which is consistent with improved flow to the kidneys. (d-f) Coronal (d) and axial (e, f) subvolume MIP images obtained after renal artery revascularization show increased caliber of both renal arteries. Minimal residual narrowing of the left renal artery origin is seen (d, f); however, the PC image (f) shows no residual spin dephasing to suggest hemodynamic significance. The postrevascularization gadolinium-enhanced MR angiography volume (d) was acquired with a longer delay after contrast material infusion, which accounts for the better visualization of the left renal vein (L) and portal vein (P).

View larger version (70K): [in a new window]   Figure 1f.   Bilateral renal artery stenosis in a 65-year-old woman. (a) Coronal gadolinium-enhanced MR angiogram shows bilateral renal artery stenosis (arrows). (b) Axial 3D PC image shows signal dropout (arrows), which indicates hemodynamic significance (1). (c) Axial PC image obtained after bilateral percutaneous angioplasty shows diminished spin dephasing, which is consistent with improved flow to the kidneys. (d-f) Coronal (d) and axial (e, f) subvolume MIP images obtained after renal artery revascularization show increased caliber of both renal arteries. Minimal residual narrowing of the left renal artery origin is seen (d, f); however, the PC image (f) shows no residual spin dephasing to suggest hemodynamic significance. The postrevascularization gadolinium-enhanced MR angiography volume (d) was acquired with a longer delay after contrast material infusion, which accounts for the better visualization of the left renal vein (L) and portal vein (P).

View larger version (123K): [in a new window]   Figure 2a.   Unilateral renal artery stenosis in a 67-year-old man after percutaneous transluminal angioplasty and Palmaz stent placement. (a) Axial T2-weighted MR image at the level of the right renal artery origin shows an oval region of signal dropout with an irregular halo of intense brightness (arrow), which indicates the presence of a metallic stent. (b) Coronal subvolume MIP image from gadolinium-enhanced MR angiography shows the signal dropout (arrow), which limits full evaluation of the revascularized renal artery.

View larger version (112K): [in a new window]   Figure 2b.   Unilateral renal artery stenosis in a 67-year-old man after percutaneous transluminal angioplasty and Palmaz stent placement. (a) Axial T2-weighted MR image at the level of the right renal artery origin shows an oval region of signal dropout with an irregular halo of intense brightness (arrow), which indicates the presence of a metallic stent. (b) Coronal subvolume MIP image from gadolinium-enhanced MR angiography shows the signal dropout (arrow), which limits full evaluation of the revascularized renal artery.

View larger version (155K): [in a new window]   Figure 3a.   Bilateral renal artery stenosis in a 43-year-old man. (a) Coronal arterial-phase 3D MIP image shows an irregular aorta with mural plaque. Focal segmental stenoses affect the right and left common iliac arteries and the left external iliac artery. The right renal artery is nearly occluded at its origin (arrow). The proximal superior mesenteric artery (black arrowhead) obscures the left renal artery (white arrowhead). (b) Coronal subvolume MIP image centered at the renal arteries shows severe bilateral renal artery stenosis. (c) Coronal MR image obtained after aortorenal endarterectomy shows increased renal artery caliber and an improved aortic contour.

View larger version (121K): [in a new window]   Figure 3b.   Bilateral renal artery stenosis in a 43-year-old man. (a) Coronal arterial-phase 3D MIP image shows an irregular aorta with mural plaque. Focal segmental stenoses affect the right and left common iliac arteries and the left external iliac artery. The right renal artery is nearly occluded at its origin (arrow). The proximal superior mesenteric artery (black arrowhead) obscures the left renal artery (white arrowhead). (b) Coronal subvolume MIP image centered at the renal arteries shows severe bilateral renal artery stenosis. (c) Coronal MR image obtained after aortorenal endarterectomy shows increased renal artery caliber and an improved aortic contour.

View larger version (151K): [in a new window]   Figure 3c.   Bilateral renal artery stenosis in a 43-year-old man. (a) Coronal arterial-phase 3D MIP image shows an irregular aorta with mural plaque. Focal segmental stenoses affect the right and left common iliac arteries and the left external iliac artery. The right renal artery is nearly occluded at its origin (arrow). The proximal superior mesenteric artery (black arrowhead) obscures the left renal artery (white arrowhead). (b) Coronal subvolume MIP image centered at the renal arteries shows severe bilateral renal artery stenosis. (c) Coronal MR image obtained after aortorenal endarterectomy shows increased renal artery caliber and an improved aortic contour.

View larger version (69K): [in a new window]   Figure 4a.   Bilateral renal artery stenosis in a 59-year-old man. (a, b) Sagittal (a) and coronal (b) MR images show a complex perirenal abdominal aortic aneurysm, which terminates 2 cm above the iliac bifurcation. Both proximal renal arteries are severely stenosed (arrows); the celiac artery (C) and superior mesenteric artery (S) are patent. (c) Coronal MR image obtained after aneurysmectomy and bilateral aortorenal endarterectomy shows increased caliber of the proximal renal arteries. The diseased infrarenal aorta was replaced by a graft (G), with residual dilatation of the perirenal aorta (arrowhead).

View larger version (95K): [in a new window]   Figure 4b.   Bilateral renal artery stenosis in a 59-year-old man. (a, b) Sagittal (a) and coronal (b) MR images show a complex perirenal abdominal aortic aneurysm, which terminates 2 cm above the iliac bifurcation. Both proximal renal arteries are severely stenosed (arrows); the celiac artery (C) and superior mesenteric artery (S) are patent. (c) Coronal MR image obtained after aneurysmectomy and bilateral aortorenal endarterectomy shows increased caliber of the proximal renal arteries. The diseased infrarenal aorta was replaced by a graft (G), with residual dilatation of the perirenal aorta (arrowhead).

View larger version (100K): [in a new window]   Figure 4c.   Bilateral renal artery stenosis in a 59-year-old man. (a, b) Sagittal (a) and coronal (b) MR images show a complex perirenal abdominal aortic aneurysm, which terminates 2 cm above the iliac bifurcation. Both proximal renal arteries are severely stenosed (arrows); the celiac artery (C) and superior mesenteric artery (S) are patent. (c) Coronal MR image obtained after aneurysmectomy and bilateral aortorenal endarterectomy shows increased caliber of the proximal renal arteries. The diseased infrarenal aorta was replaced by a graft (G), with residual dilatation of the perirenal aorta (arrowhead).

View larger version (122K): [in a new window]   Figure 5a.   Normal findings in a 51-year-old man after bilateral aortorenal bypass for renal artery stenosis. (a) Coronal subvolume MIP image from gadolinium-enhanced MR angiography shows patency of both bypass grafts with minor irregularity of the distal anastomosis on the right (arrow). (b) Coronal 3D PC image shows patent bypass grafts with no flow disturbance at the site of anastomotic irregularity (arrowhead). I = inferior vena cava.

View larger version (109K): [in a new window]   Figure 5b.   Normal findings in a 51-year-old man after bilateral aortorenal bypass for renal artery stenosis. (a) Coronal subvolume MIP image from gadolinium-enhanced MR angiography shows patency of both bypass grafts with minor irregularity of the distal anastomosis on the right (arrow). (b) Coronal 3D PC image shows patent bypass grafts with no flow disturbance at the site of anastomotic irregularity (arrowhead). I = inferior vena cava.

View larger version (153K): [in a new window]   Figure 6a.   Renal artery stenosis in a 74-year-old man who had undergone left nephrectomy. (a) Coronal gadolinium-enhanced MR angiogram shows severe right renal artery stenosis (arrow). (b) Coronal subvolume MIP image shows the anatomy after placement of an aortorenal bypass graft (arrow). IMA = inferior mesenteric artery.

View larger version (142K): [in a new window]   Figure 6b.   Renal artery stenosis in a 74-year-old man who had undergone left nephrectomy. (a) Coronal gadolinium-enhanced MR angiogram shows severe right renal artery stenosis (arrow). (b) Coronal subvolume MIP image shows the anatomy after placement of an aortorenal bypass graft (arrow). IMA = inferior mesenteric artery.

View larger version (113K): [in a new window]   Figure 7a.   Bilateral fibromuscular dysplasia of the renal arteries in a 51-year-old woman. (a) Coronal gadolinium-enhanced MR angiogram shows beading of both distal renal arteries (arrowheads). Note the focal narrowing of the proximal left renal artery (arrow). (b) Axial 3D PC image shows spin dephasing (arrow), which is suggestive of hemodynamic significance. There is also signal dropout in the segmentally stenosed distal renal arteries due to turbulent flow. (c) Coronal gadolinium-enhanced MR angiogram obtained after bilateral aortorenal bypass shows the grafts. Arrowhead = stump of native right renal artery. (d-f) Sequential axial 3D PC images (presented from superior [d] to inferior [f]) show no flow disturbance. Note that the right renal graft (arrow) originates anterior to the inferior vena cava (I) and inferior to the left renal vein (L).

View larger version (63K): [in a new window]   Figure 7b.   Bilateral fibromuscular dysplasia of the renal arteries in a 51-year-old woman. (a) Coronal gadolinium-enhanced MR angiogram shows beading of both distal renal arteries (arrowheads). Note the focal narrowing of the proximal left renal artery (arrow). (b) Axial 3D PC image shows spin dephasing (arrow), which is suggestive of hemodynamic significance. There is also signal dropout in the segmentally stenosed distal renal arteries due to turbulent flow. (c) Coronal gadolinium-enhanced MR angiogram obtained after bilateral aortorenal bypass shows the grafts. Arrowhead = stump of native right renal artery. (d-f) Sequential axial 3D PC images (presented from superior [d] to inferior [f]) show no flow disturbance. Note that the right renal graft (arrow) originates anterior to the inferior vena cava (I) and inferior to the left renal vein (L).

View larger version (106K): [in a new window]   Figure 7c.   Bilateral fibromuscular dysplasia of the renal arteries in a 51-year-old woman. (a) Coronal gadolinium-enhanced MR angiogram shows beading of both distal renal arteries (arrowheads). Note the focal narrowing of the proximal left renal artery (arrow). (b) Axial 3D PC image shows spin dephasing (arrow), which is suggestive of hemodynamic significance. There is also signal dropout in the segmentally stenosed distal renal arteries due to turbulent flow. (c) Coronal gadolinium-enhanced MR angiogram obtained after bilateral aortorenal bypass shows the grafts. Arrowhead = stump of native right renal artery. (d-f) Sequential axial 3D PC images (presented from superior [d] to inferior [f]) show no flow disturbance. Note that the right renal graft (arrow) originates anterior to the inferior vena cava (I) and inferior to the left renal vein (L).

View larger version (57K): [in a new window]   Figure 7d.   Bilateral fibromuscular dysplasia of the renal arteries in a 51-year-old woman. (a) Coronal gadolinium-enhanced MR angiogram shows beading of both distal renal arteries (arrowheads). Note the focal narrowing of the proximal left renal artery (arrow). (b) Axial 3D PC image shows spin dephasing (arrow), which is suggestive of hemodynamic significance. There is also signal dropout in the segmentally stenosed distal renal arteries due to turbulent flow. (c) Coronal gadolinium-enhanced MR angiogram obtained after bilateral aortorenal bypass shows the grafts. Arrowhead = stump of native right renal artery. (d-f) Sequential axial 3D PC images (presented from superior [d] to inferior [f]) show no flow disturbance. Note that the right renal graft (arrow) originates anterior to the inferior vena cava (I) and inferior to the left renal vein (L).

View larger version (57K): [in a new window]   Figure 7e.   Bilateral fibromuscular dysplasia of the renal arteries in a 51-year-old woman. (a) Coronal gadolinium-enhanced MR angiogram shows beading of both distal renal arteries (arrowheads). Note the focal narrowing of the proximal left renal artery (arrow). (b) Axial 3D PC image shows spin dephasing (arrow), which is suggestive of hemodynamic significance. There is also signal dropout in the segmentally stenosed distal renal arteries due to turbulent flow. (c) Coronal gadolinium-enhanced MR angiogram obtained after bilateral aortorenal bypass shows the grafts. Arrowhead = stump of native right renal artery. (d-f) Sequential axial 3D PC images (presented from superior [d] to inferior [f]) show no flow disturbance. Note that the right renal graft (arrow) originates anterior to the inferior vena cava (I) and inferior to the left renal vein (L).

View larger version (53K): [in a new window]   Figure 7f.   Bilateral fibromuscular dysplasia of the renal arteries in a 51-year-old woman. (a) Coronal gadolinium-enhanced MR angiogram shows beading of both distal renal arteries (arrowheads). Note the focal narrowing of the proximal left renal artery (arrow). (b) Axial 3D PC image shows spin dephasing (arrow), which is suggestive of hemodynamic significance. There is also signal dropout in the segmentally stenosed distal renal arteries due to turbulent flow. (c) Coronal gadolinium-enhanced MR angiogram obtained after bilateral aortorenal bypass shows the grafts. Arrowhead = stump of native right renal artery. (d-f) Sequential axial 3D PC images (presented from superior [d] to inferior [f]) show no flow disturbance. Note that the right renal graft (arrow) originates anterior to the inferior vena cava (I) and inferior to the left renal vein (L).

View larger version (169K): [in a new window]   Figure 8a.   Unilateral renal artery stenosis in a 64-year-old woman. (a) Coronal gadolinium-enhanced MR angiogram shows severe left renal artery stenosis (solid arrow). The irregularity of the distal aorta (open arrow) represents incomplete enhancement of a severely atherosclerotic infrarenal aneurysm. (b) Coronal gadolinium-enhanced MR angiogram obtained after splenorenal bypass shows the graft (arrow). (c) Oblique reconstruction image obtained parallel to the course of the graft shows the anastomosis most accurately (arrow). GD = gastroduodenal artery, H = common hepatic artery, R = right renal artery, S = superior mesenteric artery, Spl = splenic artery.

View larger version (177K): [in a new window]   Figure 8b.   Unilateral renal artery stenosis in a 64-year-old woman. (a) Coronal gadolinium-enhanced MR angiogram shows severe left renal artery stenosis (solid arrow). The irregularity of the distal aorta (open arrow) represents incomplete enhancement of a severely atherosclerotic infrarenal aneurysm. (b) Coronal gadolinium-enhanced MR angiogram obtained after splenorenal bypass shows the graft (arrow). (c) Oblique reconstruction image obtained parallel to the course of the graft shows the anastomosis most accurately (arrow). GD = gastroduodenal artery, H = common hepatic artery, R = right renal artery, S = superior mesenteric artery, Spl = splenic artery.

View larger version (121K): [in a new window]   Figure 8c.   Unilateral renal artery stenosis in a 64-year-old woman. (a) Coronal gadolinium-enhanced MR angiogram shows severe left renal artery stenosis (solid arrow). The irregularity of the distal aorta (open arrow) represents incomplete enhancement of a severely atherosclerotic infrarenal aneurysm. (b) Coronal gadolinium-enhanced MR angiogram obtained after splenorenal bypass shows the graft (arrow). (c) Oblique reconstruction image obtained parallel to the course of the graft shows the anastomosis most accurately (arrow). GD = gastroduodenal artery, H = common hepatic artery, R = right renal artery, S = superior mesenteric artery, Spl = splenic artery.

View larger version (116K): [in a new window]   Figure 9a.   Renal artery stenosis in a 65-year-old woman who had undergone left nephrectomy. (a) Coronal subvolume MIP image shows severe right renal artery stenosis (arrow). (b) Coronal subvolume MIP image obtained after gastroduodenal-renal bypass does not clearly show the anastomosis (arrow) due to the coronal projection. (c) Oblique MIP image obtained in the plane of the graft shows the anastomosis (arrow). GD = gastroduodenal artery, H = proper hepatic artery, S = superior mesenteric artery.

View larger version (132K): [in a new window]   Figure 9b.   Renal artery stenosis in a 65-year-old woman who had undergone left nephrectomy. (a) Coronal subvolume MIP image shows severe right renal artery stenosis (arrow). (b) Coronal subvolume MIP image obtained after gastroduodenal-renal bypass does not clearly show the anastomosis (arrow) due to the coronal projection. (c) Oblique MIP image obtained in the plane of the graft shows the anastomosis (arrow). GD = gastroduodenal artery, H = proper hepatic artery, S = superior mesenteric artery.

View larger version (134K): [in a new window]   Figure 9c.   Renal artery stenosis in a 65-year-old woman who had undergone left nephrectomy. (a) Coronal subvolume MIP image shows severe right renal artery stenosis (arrow). (b) Coronal subvolume MIP image obtained after gastroduodenal-renal bypass does not clearly show the anastomosis (arrow) due to the coronal projection. (c) Oblique MIP image obtained in the plane of the graft shows the anastomosis (arrow). GD = gastroduodenal artery, H = proper hepatic artery, S = superior mesenteric artery.

View larger version (146K): [in a new window]   Figure 10a.   Thrombosis in a 65-year-old man with anuria and increased creatinine level 2 days after aortobifemoral bypass and bilateral aortorenal endarterectomy. (a) Coronal gadolinium-enhanced MR angiogram shows acute thrombosis of the right renal artery (arrow). (b) Oblique MIP image shows extension of the thrombosis into the aorta (arrow). (c, d) Oblique MR images show peripheral perfusion defects in both kidneys (arrowhead), which indicate renal parenchymal infarcts. (Fig 10a reprinted, with permission, from reference 13.)

View larger version (156K): [in a new window]   Figure 10b.   Thrombosis in a 65-year-old man with anuria and increased creatinine level 2 days after aortobifemoral bypass and bilateral aortorenal endarterectomy. (a) Coronal gadolinium-enhanced MR angiogram shows acute thrombosis of the right renal artery (arrow). (b) Oblique MIP image shows extension of the thrombosis into the aorta (arrow). (c, d) Oblique MR images show peripheral perfusion defects in both kidneys (arrowhead), which indicate renal parenchymal infarcts. (Fig 10a reprinted, with permission, from reference 13.)

View larger version (168K): [in a new window]   Figure 10c.   Thrombosis in a 65-year-old man with anuria and increased creatinine level 2 days after aortobifemoral bypass and bilateral aortorenal endarterectomy. (a) Coronal gadolinium-enhanced MR angiogram shows acute thrombosis of the right renal artery (arrow). (b) Oblique MIP image shows extension of the thrombosis into the aorta (arrow). (c, d) Oblique MR images show peripheral perfusion defects in both kidneys (arrowhead), which indicate renal parenchymal infarcts. (Fig 10a reprinted, with permission, from reference 13.)

View larger version (167K): [in a new window]   Figure 10d.   Thrombosis in a 65-year-old man with anuria and increased creatinine level 2 days after aortobifemoral bypass and bilateral aortorenal endarterectomy. (a) Coronal gadolinium-enhanced MR angiogram shows acute thrombosis of the right renal artery (arrow). (b) Oblique MIP image shows extension of the thrombosis into the aorta (arrow). (c, d) Oblique MR images show peripheral perfusion defects in both kidneys (arrowhead), which indicate renal parenchymal infarcts. (Fig 10a reprinted, with permission, from reference 13.)

View larger version (155K): [in a new window]   Figure 11a.   Hemorrhage in a 68-year-old woman with decreased hematocrit and decreased urine output 7 days after infrarenal aortobifemoral bypass, left aortorenal bypass, and right nephrectomy. (a) Coronal gadolinium-enhanced MR angiogram shows patency of the aortorenal graft (arrow). (b, c) Sagittal T1-weighted (b) and contrast material-enhanced axial fat-saturated T1-weighted (c) MR images show a fluid collection with heterogeneous signal intensity (arrow). The fluid collection is indicative of subcapsular and perirenal hemorrhage. (d-f) Arterial-phase (d), venous-phase (e), and delayed-phase (f) coronal MR images show extrarenal accumulation of contrast material, which represents active bleeding.

View larger version (175K): [in a new window]   Figure 11b.   Hemorrhage in a 68-year-old woman with decreased hematocrit and decreased urine output 7 days after infrarenal aortobifemoral bypass, left aortorenal bypass, and right nephrectomy. (a) Coronal gadolinium-enhanced MR angiogram shows patency of the aortorenal graft (arrow). (b, c) Sagittal T1-weighted (b) and contrast material-enhanced axial fat-saturated T1-weighted (c) MR images show a fluid collection with heterogeneous signal intensity (arrow). The fluid collection is indicative of subcapsular and perirenal hemorrhage. (d-f) Arterial-phase (d), venous-phase (e), and delayed-phase (f) coronal MR images show extrarenal accumulation of contrast material, which represents active bleeding.

View larger version (139K): [in a new window]   Figure 11c.   Hemorrhage in a 68-year-old woman with decreased hematocrit and decreased urine output 7 days after infrarenal aortobifemoral bypass, left aortorenal bypass, and right nephrectomy. (a) Coronal gadolinium-enhanced MR angiogram shows patency of the aortorenal graft (arrow). (b, c) Sagittal T1-weighted (b) and contrast material-enhanced axial fat-saturated T1-weighted (c) MR images show a fluid collection with heterogeneous signal intensity (arrow). The fluid collection is indicative of subcapsular and perirenal hemorrhage. (d-f) Arterial-phase (d), venous-phase (e), and delayed-phase (f) coronal MR images show extrarenal accumulation of contrast material, which represents active bleeding.

View larger version (149K): [in a new window]   Figure 11d.   Hemorrhage in a 68-year-old woman with decreased hematocrit and decreased urine output 7 days after infrarenal aortobifemoral bypass, left aortorenal bypass, and right nephrectomy. (a) Coronal gadolinium-enhanced MR angiogram shows patency of the aortorenal graft (arrow). (b, c) Sagittal T1-weighted (b) and contrast material-enhanced axial fat-saturated T1-weighted (c) MR images show a fluid collection with heterogeneous signal intensity (arrow). The fluid collection is indicative of subcapsular and perirenal hemorrhage. (d-f) Arterial-phase (d), venous-phase (e), and delayed-phase (f) coronal MR images show extrarenal accumulation of contrast material, which represents active bleeding.

View larger version (156K): [in a new window]   Figure 11e.   Hemorrhage in a 68-year-old woman with decreased hematocrit and decreased urine output 7 days after infrarenal aortobifemoral bypass, left aortorenal bypass, and right nephrectomy. (a) Coronal gadolinium-enhanced MR angiogram shows patency of the aortorenal graft (arrow). (b, c) Sagittal T1-weighted (b) and contrast material-enhanced axial fat-saturated T1-weighted (c) MR images show a fluid collection with heterogeneous signal intensity (arrow). The fluid collection is indicative of subcapsular and perirenal hemorrhage. (d-f) Arterial-phase (d), venous-phase (e), and delayed-phase (f) coronal MR images show extrarenal accumulation of contrast material, which represents active bleeding.

View larger version (155K): [in a new window]   Figure 11f.   Hemorrhage in a 68-year-old woman with decreased hematocrit and decreased urine output 7 days after infrarenal aortobifemoral bypass, left aortorenal bypass, and right nephrectomy. (a) Coronal gadolinium-enhanced MR angiogram shows patency of the aortorenal graft (arrow). (b, c) Sagittal T1-weighted (b) and contrast material-enhanced axial fat-saturated T1-weighted (c) MR images show a fluid collection with heterogeneous signal intensity (arrow). The fluid collection is indicative of subcapsular and perirenal hemorrhage. (d-f) Arterial-phase (d), venous-phase (e), and delayed-phase (f) coronal MR images show extrarenal accumulation of contrast material, which represents active bleeding.

View larger version (126K): [in a new window]   Figure 12a.   Aortic dissection in a 59-year-old man after bilateral endarterectomy of the main renal arteries and accessory renal arteries. (a) Coronal 3D MIP image from gadolinium-enhanced MR angiography shows bilateral renal artery stenosis (arrows) and bilateral accessory renal arteries (arrowheads). (b) Postrevascularization coronal 3D MIP image from gadolinium-enhanced MR angiography shows a dissection of the infrarenal aorta as a subtle linear filling defect with associated mural contour deformity (arrow). Arrowheads = accessory renal arteries. (c) Coronal 5-mm-thick MIP subvolume reconstruction image shows the extent of the dissection flap (arrow). The dissection was treated with a Wallstent.

View larger version (125K): [in a new window]   Figure 12b.   Aortic dissection in a 59-year-old man after bilateral endarterectomy of the main renal arteries and accessory renal arteries. (a) Coronal 3D MIP image from gadolinium-enhanced MR angiography shows bilateral renal artery stenosis (arrows) and bilateral accessory renal arteries (arrowheads). (b) Postrevascularization coronal 3D MIP image from gadolinium-enhanced MR angiography shows a dissection of the infrarenal aorta as a subtle linear filling defect with associated mural contour deformity (arrow). Arrowheads = accessory renal arteries. (c) Coronal 5-mm-thick MIP subvolume reconstruction image shows the extent of the dissection flap (arrow). The dissection was treated with a Wallstent.

View larger version (109K): [in a new window]   Figure 12c.   Aortic dissection in a 59-year-old man after bilateral endarterectomy of the main renal arteries and accessory renal arteries. (a) Coronal 3D MIP image from gadolinium-enhanced MR angiography shows bilateral renal artery stenosis (arrows) and bilateral accessory renal arteries (arrowheads). (b) Postrevascularization coronal 3D MIP image from gadolinium-enhanced MR angiography shows a dissection of the infrarenal aorta as a subtle linear filling defect with associated mural contour deformity (arrow). Arrowheads = accessory renal arteries. (c) Coronal 5-mm-thick MIP subvolume reconstruction image shows the extent of the dissection flap (arrow). The dissection was treated with a Wallstent.

View larger version (133K): [in a new window]   Figure 13.   Bypass graft pseudoaneurysm in a 66-year-old man after left aortorenal bypass. Arterial-phase coronal gadolinium-enhanced MR angiogram shows a pseudoaneurysm at the orifice of the graft (straight arrow). Note the near occlusion of the right renal artery (small arrowhead). The right common iliac artery is occluded beyond its origin (large arrowhead). The left external iliac artery is segmentally stenosed (curved arrow).

View larger version (154K): [in a new window]   Figure 14a.   Bypass graft pseudoaneurysms in a 70-year-old man with recurrent hypertension 10 years after right iliorenal bypass. (a) Coronal 3D MIP image shows pseudoaneurysms of the proximal and distal aspects of the graft; however, the size of the dilated segments is underestimated. (b-d) Coronal subvolume MIP image (b) and axial subvolume MIP images reconstructed at the level of the superior graft anastomosis (c) and inferior graft anastomosis (d) show the true extent of the dilatation, including areas of thrombosis (arrows).

View larger version (172K): [in a new window]   Figure 14b.   Bypass graft pseudoaneurysms in a 70-year-old man with recurrent hypertension 10 years after right iliorenal bypass. (a) Coronal 3D MIP image shows pseudoaneurysms of the proximal and distal aspects of the graft; however, the size of the dilated segments is underestimated. (b-d) Coronal subvolume MIP image (b) and axial subvolume MIP images reconstructed at the level of the superior graft anastomosis (c) and inferior graft anastomosis (d) show the true extent of the dilatation, including areas of thrombosis (arrows).

View larger version (66K): [in a new window]   Figure 14c.   Bypass graft pseudoaneurysms in a 70-year-old man with recurrent hypertension 10 years after right iliorenal bypass. (a) Coronal 3D MIP image shows pseudoaneurysms of the proximal and distal aspects of the graft; however, the size of the dilated segments is underestimated. (b-d) Coronal subvolume MIP image (b) and axial subvolume MIP images reconstructed at the level of the superior graft anastomosis (c) and inferior graft anastomosis (d) show the true extent of the dilatation, including areas of thrombosis (arrows).

View larger version (64K): [in a new window]   Figure 14d.   Bypass graft pseudoaneurysms in a 70-year-old man with recurrent hypertension 10 years after right iliorenal bypass. (a) Coronal 3D MIP image shows pseudoaneurysms of the proximal and distal aspects of the graft; however, the size of the dilated segments is underestimated. (b-d) Coronal subvolume MIP image (b) and axial subvolume MIP images reconstructed at the level of the superior graft anastomosis (c) and inferior graft anastomosis (d) show the true extent of the dilatation, including areas of thrombosis (arrows).

View larger version (169K): [in a new window]   Figure 15a.   Right renal artery occlusion and left renal artery stenosis in a 72-year-old man after percutaneous transluminal angioplasty of the left renal artery. (a) Conventional angiogram shows residual stenosis of the left renal artery (arrow). However, no pressure gradient could be demonstrated immediately after angioplasty. Eleven months later, the patient experienced gradually increasing hypertension refractory to medication and slowly worsening renal function. (b) Coronal subvolume MIP image from gadolinium-enhanced MR angiography shows progression of the left renal artery stenosis to near occlusion (arrow). The right renal artery remains occluded. (c) Axial PC image shows signal dropout at the site of the stenosis (arrowhead) with a jet of dephasing distal to the stenosis.

View larger version (145K): [in a new window]   Figure 15b.   Right renal artery occlusion and left renal artery stenosis in a 72-year-old man after percutaneous transluminal angioplasty of the left renal artery. (a) Conventional angiogram shows residual stenosis of the left renal artery (arrow). However, no pressure gradient could be demonstrated immediately after angioplasty. Eleven months later, the patient experienced gradually increasing hypertension refractory to medication and slowly worsening renal function. (b) Coronal subvolume MIP image from gadolinium-enhanced MR angiography shows progression of the left renal artery stenosis to near occlusion (arrow). The right renal artery remains occluded. (c) Axial PC image shows signal dropout at the site of the stenosis (arrowhead) with a jet of dephasing distal to the stenosis.

View larger version (101K): [in a new window]   Figure 15c.   Right renal artery occlusion and left renal artery stenosis in a 72-year-old man after percutaneous transluminal angioplasty of the left renal artery. (a) Conventional angiogram shows residual stenosis of the left renal artery (arrow). However, no pressure gradient could be demonstrated immediately after angioplasty. Eleven months later, the patient experienced gradually increasing hypertension refractory to medication and slowly worsening renal function. (b) Coronal subvolume MIP image from gadolinium-enhanced MR angiography shows progression of the left renal artery stenosis to near occlusion (arrow). The right renal artery remains occluded. (c) Axial PC image shows signal dropout at the site of the stenosis (arrowhead) with a jet of dephasing distal to the stenosis.