1/9. Radionuclide renography: a personal approach.Recent advances have increased the value of radionuclide renography in evaluating the patient with suspected disease of the genitourinary tract. The use of the consensus process to help standardize procedures and recommend interpretative criteria provides guidance for the nuclear medicine practitioner, serves as a basis to improve the standard of practice, and facilitates pooling of data from different centers. This review draws on the consensus criteria to present a personal approach to radionuclide renography with a particular emphasis on diuresis renography and the detection of renovascular hypertension. patients are encouraged to come well hydrated and void immediately prior to the study. Our standard radiopharmaceutical is 99mTc mercaptoacetyltriglycine (MAG3). Routine quantitative indices include a MAG3 clearance, whole kidney and cortical (parenchymal) regions of interest, measurements of relative uptake, time to peak height (Tmax), 20 min/max count ratio, residual urine volume and a T(1/2) in patients undergoing diuresis renography. A 1-minute image of the injection site is obtained at the conclusion of the study to check for infiltration because infiltration can invalidate a plasma sample clearance and alter the renogram curve. A postvoid image of the kidneys and bladder is obtained to calculate residual urine volume and to better evaluate drainage from the collecting system. In patients undergoing diuresis renography, the T(1/2) is calculated using a region of interest around the activity in the dilated collecting system. A prolonged T(1/2), however, should never be the sole criterion for diagnosing the presence of obstruction; the T(1/2) must be interpreted in the context of the sequential images, total and individual kidney function, other quantitative indices and available diagnostic studies. The goal of ACE inhibitor renography is to detect renovascular hypertension, not renal artery stenosis. patients with a positive study have a high probability of cure or amelioration of the hypertension following revascularization. In patients with azotemia or in patients with a small, poorly functioning kidney, the test result is often indeterminate (intermediate probability) with an abnormal baseline study that does not change following ACE inhibition. In patients with normal renal function, the test is highly accurate. To avoid unrealistic expectations on the part of the referring physician, it is often helpful to explain the likely differences in test results in these two-patient populations prior to the study.- - - - - - - - - - ranking = 1keywords = physician (Clic here for more details about this article) |
2/9. The hyponatraemic hypertensive syndrome in a 2-year-old child with behavioural symptoms.In this case report we present a 2-year-old girl with the classical signs of the hyponatraemic hypertensive syndrome. She initially presented with a history of behavioural abnormalities and hyponatraemia (126 mmol/l) and her blood pressure was as high as 220/160 mmHg. After admission, somnolence developed. Intravenous anti-hypertensive therapy was started immediately. The hyponatraemia was treated with i.v. sodium supplementation. The cause of this syndrome proved to be fibromuscular dysplasia of the left renal artery. Finally, a left nephrectomy was performed. With this therapy, blood pressure and serum sodium normalised and the girl promptly regained normal consciousness and behaviour. CONCLUSION: Behavioural abnormalities in the history of a child without any other neurological symptoms might be one of the first signs of hypertensive encephalopathy. In combination with hyponatraemia, these symptoms should alert the physician to consider the hyponatraemic hypertensive syndrome.- - - - - - - - - - ranking = 1keywords = physician (Clic here for more details about this article) |
3/9. Three-dimensional reconstruction of a rotational abdominal aortogram showing a renal artery aneurysm.This is a case of a 65-year-old woman with a history of coronary artery disease, who presented with hypertension that was poorly controlled by medical treatment. A rotational abdominal aortogram was done, followed by selective right and left renal artery angiograms. Imaging of renal artery aneurysms can be tricky, and some aneurysms might be misdiagnosed for a tortuous renal artery. In such cases, the physician needs to maintain a high index of suspicion towards this condition. Three-dimensional reconstruction allows for a better visualization of the aneurysm and its surrounding structures. It also guides the operator to the projection that best reveals the anatomical criteria of the aneurysm.- - - - - - - - - - ranking = 1keywords = physician (Clic here for more details about this article) |
4/9. Reversal of end-stage renal disease after aortic dissection using renal artery stent: a case report.BACKGROUND: Medical management is the conventional treatment for Stanford Type B aortic dissections as surgery is associated with significant morbidity and mortality. The advent of endovascular interventional techniques has revived interest in treating end-organ complications of Type B aortic dissection. We describe a patient who benefited from endovascular repair of renal artery stenosis caused by a dissection flap, which resulted in reversal of his end-stage renal disease (ESRD). CASE PRESENTATION: A 69 y/o male with a Type B aortic dissection diagnosed two months earlier was found to have a serum creatinine of 15.2 mg/dL (1343.7 micromol/L) on routine visit to his primary care physician. An MRA demonstrated a rightward spiraling aortic dissection flap involving the origins of the celiac artery, superior mesenteric artery, and both renal arteries. The right renal artery arose from the false lumen with lack of blood flow to the right kidney. The left renal artery arose from the true lumen, but an intimal dissection flap appeared to be causing an intermittent stenosis of the left renal artery with compromised blood flow to the left kidney. Endovascular reconstruction with of the left renal artery with stent placement was performed. Hemodialysis was successfully discontinued six weeks after stent placement. CONCLUSION: Percutaneous intervention provides a promising alternative for patients with Type B aortic dissections when medical treatment will not improve the likelihood of meaningful recovery and surgery entails too great a risk. Nephrologists should therefore be aggressive in the workup of ischemic renal failure associated with aortic dissection as percutaneous intervention may reverse the effects of renal failure in this population.- - - - - - - - - - ranking = 1keywords = physician (Clic here for more details about this article) |
5/9. The use of brachytherapy to treat renal artery in-stent restenosis.The percutaneous treatment of renal artery stenosis has become the accepted revascularization strategy by most physicians treating this disorder. Unfortunately, as renal artery angioplasty and stent implantation become increasingly prevalent the Achilles heel of angioplasty, in-stent restenosis, also rises. There are currently no data suggestive of the optimal treatment strategy for renal artery in-stent restenosis. However, given the similarities in the pathophysiology between renal artery and coronary artery in-stent restenosis, brachytherapy is considered a reasonable option. This is the strategy that has been suggested and used by a number of operators. This case report describes two examples of renal artery in-stent restenosis treated with angioplasty and brachytherapy.- - - - - - - - - - ranking = 1keywords = physician (Clic here for more details about this article) |
6/9. Hypertensive crisis managed by bilateral renal artery reconstruction.In hypertensive emergencies the physician is obligated to reduce arterial pressure immediately. This is best done with intravenous antihypertensive agents. If renal artery occlusion is demonstrated and the patient is refractory to appropriate medications, renal artery reconstruction may be necessary. In the poor risk patient, an attempt at transcatheter thromboembolectomy may be worthwhile. If this maneuver is unsuccessful, emergent aorto-renal reconstruction is indicated. A case of bilateral renal artery thromboses causing a hypertensive crisis which was successfully managed by aorto-renal bypass grafting is reported.- - - - - - - - - - ranking = 1keywords = physician (Clic here for more details about this article) |
7/9. Normal-appearing captopril MAG-3 renal scintigraphy in hemodynamically significant renal artery stenosis. A case report.The finding from a normal-appearing angiotensin converting enzyme (ACE)-inhibitor renal scan is generally reassuring to the physician screening for renovascular hypertension. In fact, the false-negative rate for captopril scintigraphy is very low. Possible reasons for false-negative scans have not been well documented. A fifty-two-year-old man was evaluated and found to have renovascular hypertension on two occasions, at initial presentation and again eight months later (restenosis had occurred). Renovascular hypertension was present on both occasions as judged by decline of blood pressure following angioplasty of right renal artery stenosis (approximately 80% and approximately 70% stenosis on the two occasions, respectively). However, ACE-inhibitor renal scanning with 99mTc MAG-3 gave disparate results on the two occasions. The first study using oral captopril (25 mg) indicated a low probability of renal artery stenosis, whereas the second study done with the patient regularly taking lisinopril (10 mg daily) was markedly positive. Possible reasons for the initial negative study include poor absorption of oral captopril or inadequate inhibition of the renin-angiotensin system by the 25 mg dose.- - - - - - - - - - ranking = 1keywords = physician (Clic here for more details about this article) |
8/9. Acute renal vascular occlusion: an uncommon mimic.Two adult patients with acute renal vascular occlusion with infarction are described. Both patients were believed to have ureteral colic. In each instance, the correct diagnosis was overlooked at the initial emergency department visit. An uncommon clinical entity that continues to go undiagnosed, acute vascular occlusion of the kidney must be considered in the differential diagnosis of acute flank pain. Absence of the nephrogram phase on an intravenous pyelogram (IVP) should alert emergency physicians to this possible diagnosis and to the need for further work-up. Subsequent diagnostic evaluation should begin with renal ultrasonography to rule out obstructive uropathy. If hydroureteronephrosis is not present, follow-up perfusion studies are necessary to confirm the absence of renal perfusion. Greater awareness of this uncommon clinical entity and its potential morbidity is essential to correct diagnosis and management.- - - - - - - - - - ranking = 1keywords = physician (Clic here for more details about this article) |
9/9. magnetic resonance angiography and detection of renal artery stenosis in a patient with impaired renal function.Diagnosing renovascular disease in patients with renal insufficiency has challenged physicians for many years. Although contrast angiography is the "gold standard," it is associated with major risks in patients with preexisting renal failure. Other noninvasive tests have not proved to have sufficient sensitivity and specificity to supplant angiography. Developments in magnetic resonance (MR) angiographic technology, however, now enable physicians to assess the vasculature noninvasively and without use of potentially nephrotoxic agents. Herein we describe a patient with hypertension and renal failure in whom MR angiography proved to be the only effective noninvasive test for diagnosing renal artery stenosis. In addition, we review the current literature on MR angiography for renovascular disease. In the setting of renal impairment, MR angiography may be useful in screening patients for renovascular disease. More studies are needed in order to refine MR angiographic techniques and, ultimately, to determine specific situations in which MR angiography may be useful.- - - - - - - - - - ranking = 2keywords = physician (Clic here for more details about this article) |