Other imaging modalitiesRenal angiography is the most accurate test for an-atomic diagnosis of RAS, but it uses potentially nephrotoxic contrast agents and its associated radi-ation dose
Trang 1Other imaging modalities
Renal angiography is the most accurate test for
an-atomic diagnosis of RAS, but it uses potentially
nephrotoxic contrast agents and its associated
radi-ation dose is high compared with other modalities
CT angiography (CTA), magnetic resonance
angiog-raphy (MRA), and Doppler sonogangiog-raphy (DS) are
new noninvasive approaches for the diagnosis of
re-nal artery stenosis DS can be used to monitor
recur-rent stenosis after corrective therapy and is effective
for classifying patients as responders or
nonre-sponders to therapy Unfortunately, US criteria for
RAS based on evaluation of renal peak systolic
ve-locity and renal/aortic ratio are controversial CTA
and MRA provide anatomic information about
re-nal artery stenosis CTA has higher spatial
resolu-tion than MRA and can be used to evaluate the
calcium content of atherosclerotic lesions before
treatment; however, the associated radiation dose
is high and potentially nephrotoxic contrast agents are required In contrast, MRA does not expose pa-tients to ionizing radiation or directly nephrotoxic contrast agents Recently, Eklof and colleagues [92]compared DS, MRA, CTA, DS, and captopril re-nography for assessing renal artery disease and con-cluded that MRA and CTA were significantly better than duplex US and captopril renography for de-tecting hemodynamically significant RAS A meta-analysis performed by Vasbinder and colleagues [93]supports these findings
Future prospects Although captopril renography can play an impor-tant role in the evaluation of renovascular hyperten-sion, the use of this test is decreasing Recently, the clinical use of ACEI renography changed in two ways First, with the introduction of other new noninvasive imaging techniques, ACEI renography
Fig 2 Renal study with MAG3 in a patient who had suspected obstruction of the right kidney The upper row of images demonstrates rapid clearance of tracer from a small left kidney but delayed clearance from the normal-sized right kidney The time-activity curves demonstrate a marked acceleration of clearance after furosemide ad-ministration in the left kidney In contrast, the drug effect is blunted significantly in the right kidney, consistent with partial obstruction.
Nuclear Imaging in the Genitourinary Tract 31
Trang 2Interventional Uroradiology
Raul N Uppot, MD *, Debra A Gervais, MD , Peter R Mueller, MD
Percutaneous urologic interventions comprise
a wide range of techniques, including biopsies,
drainages, stone management, ureteral stenting,
re-nal vascular interventions, and tumor ablations
With advances in imaging capabilities and
percuta-neous instruments, many urologic diseases that
were once managed surgically are now managed
with minimally invasive image-guided techniques,
using only conscious sedation
Interventional uroradiology has evolved from
simple renal biopsies for diagnostic confirmation,
to percutaneous management of stones, to ablation
of renal and adrenal tumors Central to this
evolu-tion is the close cooperaevolu-tion with the urologist
and nephrologist, each of whom provides specific
skill sets and knowledge that can be used to
successfully manage the patient The purpose of this article is to detail the wide range of image-guided interventional techniques, including a dis-cussion of indications, methods, success rates, and complications
Imaging modalities Advances in imaging capabilities have spurred the evolution of minimally invasive techniques Com-pared with open surgery, image guidance allows one to target the pathology of interest while avoid-ing injury to adjacent normal tissue Modalities used in interventional uroradiology include ultra-sound, fluoroscopy, angiography, CT, and MR imaging
R A D I O L O G I C
C L I N I C S
O F N O R T H A M E R I C A
Radiol Clin N Am 46 (2008) 45–64
Division of Abdominal Imaging and Interventional Radiology, Department of Radiology, Massachusetts Gen-eral Hospital, 55 Fruit Street; White #270, Boston, MA 02114, USA
* Corresponding author.
E-mail address: ruppot@partners.org (R.N Uppot).
- Imaging modalities
Ultrasound
Fluoroscopy
Angiography
Computed tomography
Interventional MR imaging
- Preprocedure planning
Conscious sedation
- Interventional urologic procedures
Biopsy
Nonfocal renal biopsy
Focal renal biopsy
Renal cyst aspiration biopsy
Adrenal biopsy
Prostate biopsy
Transvaginal biopsy
- Image-guided percutaneous drainage and aspiration
Percutaneous nephrostomy Suprapubic tube insertion Stone management Percutaneous ureteral lithotripsy Ureteral stents
Ureteral embolization
- Renal vascular interventions Management of renal artery stenosis Renal embolization
- Ablation Radiofrequency or cryoablation Renal ablation
Adrenal ablation
- Summary
- References
45
0033-8389/08/$ – see front matter ª 2008 Elsevier Inc All rights reserved doi:10.1016/j.rcl.2008.01.010
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