lemon2008 发表于 2011-10-9 00:36:19


Which choice is the most likely diagnosis? 最符合诊断的选项是?
A Pyelonephritis. 肾盂肾炎
B Renal cell carcinoma. 肾癌
C Renal lymphoma. 肾淋巴瘤
D Papillary necrosis. 肾乳头坏死
E Acute renal infarct. 急性肾梗死


lemon2008 发表于 2011-10-9 00:47:25

Additional clinical history: The patient presented to the Emergency Department at four o'clock in the morning after having been awakened due to severe sudden onset of back and flank pain. He had no history of prior episodes, but he was later found to have had a significant medical history, including status post aortic arch repair, aortic valve replacement (titanium valve), history of Takayasu's arteritis, questionable history of TIAs, and an unreliable usage of anticoagulation. He was restarted on anticoagulation and discharged within a few days from the hospital with close follow-up.

Findings:There is segmental left renal hypo density without perinephric stranding, hematoma, or parenchymal scarring.

Differential diagnosis:鉴别诊断
Acute renal infarction 急性肾梗死
Pyelonephritis 肾盂肾炎
Vasculitis 血管炎
Renal trauma肾脏外伤

What is perinephric stranding ?

Stranding of perinephric fat is defined as linear areas of soft tissue attenuation in the perinephric space, which can result from any acute process or injury to the kidney. When unilateral perinephric stranding is identified it is most frequently the result of calyceal rupture or perinephric inflammation. Perinephric stranding is probably the manifestation of increased pressure in the collecting system in the early phase of ureteral obstruction. Perinephric stranding is easily identified on Spiral CT and less commonly seen on IVP.

lemon2008 发表于 2011-10-9 00:49:15

Diagnosis:Acute segmental left renal infarct

Key points:

What is a renal infarct & when does it occur?
Localized or global area of loss of blood/oxygen to one or both kidneys, resulting most often from sudden occlusion of the renal artery supply
Causes include: cardiac embolism (commonest cause), trauma to renal vessels (second commonest, most often blunt trauma), other cardiac causes (arrhythmias, myocardial infarction, prosthetic valve, bacterial endocarditis / septic emboli), and vascular disease (atherosclerosis, polyarteritis nodosa (PAN), SLE, dissection of aorta or renal artery)
Typical clinical history:
Sudden onset acute back or flank pain is commonest presenting symptom
Other presenting symptoms: asymptomatic, tenderness (traumatic), hematuria
Complications include: necrosis, infection, and abscess formation
Prognosis: If there is a focal infarct, there is good prognosis; if global, poor prognosis
Best imaging modality: Contrast-enhanced CT
Other recommended modalities: Color Doppler sonography & selective renal angiography
Imaging findings:
General findings of acute infarction include sharply demarcated area of decreased or poor contrast enhancement (nephrogram is decreased or absent)
A "cortical rim" sign is present in subacute infarction
Focal subsegmental infarction: Wedged-shaped hypo density with the apex of the wedge at the hilum
Focal segmental infarction: Dorsal or ventral segmental sharply demarcated hypo density
Global infarction: No renal enhancement, no excretion
Renal outline is preserved with or without medullary striations from collateral circulation ("spoke-wheel" enhancement)
If cause is due to renal artery thrombus, NO perinephric hematoma is present
If cause is due to renal artery avulsion, a large perinephric hematoma is present
US: Color Doppler may show focal or global absence of blood flow in the affected kidney
Angiography: Selective renal arteriography confirms diagnosis of renal infarction
Fluoroscopy: IVP shows focal absent or decreased nephrogram, no excretion if global infarct
MRI Findings:
T1WI & T2WI demonstrate low-signal intensity lesions
T1 C+: sharply demarcates nonenhanced infarction from densely enhancing noninfarcted tissue
Nuc Med: SPECT imaging with Tc-99m DMSA demonstrates a photon-deficient area
Imaging findings of other common differential diagnoses:
Acute demonstrates a cortical wedge-shaped or striated nephrogram (may simulate focal segmental or subsegmental infarction) with loss of normal corticomedullary differentiation, thickening of Gerota's fascia, perinephric stranding, and/or dilated calyces, pelves, or ureters
**Perinephric stranding favors pyelonephritis, as opposed to infarction
Vasculitides present as bilateral and diffuse wedge-shaped or striated nephrograms with parenchymal scarring, capsular retraction, and microaneurysmal dilatation of small vessels
Renal trauma without infarctions may present as sub capsular or perinephric hematomas, lacerations (irregular or linear hypo densities), or irregular linear or segmental nonenhancing tissue
Medical: Thrombolytics, anticoagulants, antihypertensives
Surgery or angioplasty for atherosclerosis or renal artery stenosis
Nephrectomy for irreversible traumatic global infarction

Weissledder R, Wittenberg J, Harisinghani M. Primer of Diagnostic Imaging. 2003.
Kawashima A, et al. CT Evaluation of Renovascular Disease. Radiographics. 2000; 20:1-0.


徐放鹤 发表于 2011-10-9 09:15:31

lemon2008 发表于 2011-10-9 00:49 static/image/common/back.gif
Diagnosis:Acute segmental left renal infarct


alexking 发表于 2011-10-9 14:19:28


wangjun 发表于 2011-10-9 21:01:41

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