Arteriovenous malformations of the kidneys: diagnosis and follow-up with color Doppler sonography in six patients

Congenital Renal Arteriovenous Malformation: Diagnostic Clues and Methods

Background and objectives: Renal arteriovenous malformation (AVM) is a rare disease and is difficult to be diagnosed by conventional methods because of its rarity. In this study, we investigated the diagnostic clues, and made an algorithm for the better diagnosis of renal AVM. Materials and Methods: We reviewed 13 patients who were diagnosed with AVM by using renal angiography from 1986 to 2020 at our institutes. We evaluated clinical features, diagnostic tools, treatment modalities, and outcomes after the treatment of patients. Results: All patients were female, and the mean age was 36.9 years (range 19 to 54 years). Twelve (92.3%) patients complained of gross hematuria. Four (30.8%) patients showed symptoms in relation with pregnancy and delivery. Angiographic findings demonstrated cirsoid type in 10 patients and aneurysmal type in 3 patients. Among the 11 patients who underwent computed tomography, AVMs were detected in 3 (27.3%) patients. Renal duplex Doppler was performed in 6 patients, and all of these patients were diagnosed with AVM, demonstrating a vascular turbulence or blood-rich area. Twelve patients were initially treated with transarterial embolization. Nephrectomy was performed in two patients due to persistent bleeding with hypovolemic shock. Conclusions: We should consider possible AVMs in patients who were not detected by conventional work up for hematuria, especially in mid-aged, pregnant, or recently delivered women. Renal duplex Doppler might be the optimal diagnostic modality in these patients. Our diagnostic algorithm could be aid to diagnosis and treatment for renal AVM patients.

Renal arteriovenous malformation: An unusual pathology

Renal arteriovenous malformations are rare renal vascular abnormalities. More commonly, the term refers to the congenital type of malformation. Only a few cases have ever been presented and reported in the literature, mostly with a nidus. We present the clinical, ultrasound and computed tomography findings and discuss the management related to a 63-year-old male with a right congenital renal arteriovenous malformation without a nidus that was successfully managed with coil embolisation. Relevant literature is hereby reviewed to highlight characteristic imaging and appropriate treatment.

A Renal Arteriovenous Malformation Case Study: The Importance of Utilizing Color Doppler During Point-of-Care Sonography

We report the successful diagnostic and observational treatment of a renal arteriovenous malformation (RAVM) diagnosed with point-of-care color Doppler imaging. The patient presented with clinical symptoms suggestive of hydronephrosis. A physician-performed point-of-care sonography demonstrated gray-scale imaging that initially appeared to confirm renal pelvis dilatation. However, the addition of color Doppler revealed color blooming resembling a vascular turbulence within the kidney and the renal pelvis. A computed tomography angiogram was used to confirm the diagnosis of RAVM as the etiology of renal pelvic dilation. This case highlights the potential value of using color Doppler as a standard component for physicians who evaluate patients believed to have hydronephrosis.

Wunderlich syndrome: cross-sectional imaging review

Wunderlich syndrome (WS) is a rare condition characterized by acute onset of spontaneous, nontraumatic renal hemorrhage into the subcapsular and perirenal spaces. Wunderlich syndrome is classically characterized by the Lenk's triad: acute flank pain, flank mass, and hypovolemic shock. However, the clinical manifestations can be varied and nonspecific. A wide spectrum of neoplastic and nonneoplastic renal pathologies may result in WS. Renal neoplasms are the most common cause for WS, with angiomyolipoma being the most common benign neoplasm, whereas renal cell carcinoma is the most common malignant neoplasm. Other causative conditions of WS include vascular causes (vasculitis [polyarteritis nodosa being the most common cause], renal artery aneurysms, arteriovenous malformations and fistulas, and venous thrombosis), cystic renal diseases, renal infections, calculus disease, nephritis, and coagulation disorders. Cross-sectional imaging findings help in the detection of the subcapsular and/or perinephric hemorrhage and may identify underlying etiology. Renal angiography not only helps in diagnosis of the underlying cause in select cases but also allows control of active bleeding, which can avoid unnecessary emergent radical surgery.

[Doppler US of the urinary system and renal vessels in normal and pathologic conditions]

The interest of Doppler ultrasound (US) in urinary tract investigation has dramatically increased during the past 10 years. It can provide useful diagnostic informations in pedicular and intrarenal vascular disorders, some medical nephropathies, in the assessment of renal tumors and urinary tract disorders including urolithiasis, acute obstruction and ureteral reflux. Recent technical improvements including the development of US contrast agents (microbubbles) have contributed to increase the diagnostic accuracy of the technique.

Increased detection of early vascular abnormalities after renal biopsies by color Doppler sonography

OBJECTIVE

The purpose of this study was to assess the frequency of abnormal vascular findings after renal biopsies as detected by color and pulsed Doppler sonography.

METHODS

With both color and pulsed Doppler sonography, we examined 77 patients who underwent a renal biopsy of a native kidney. The examination was carried out before and immediately after the biopsy. A follow-up sonographic assessment was performed 24 hours later. If abnormal vascular findings were detected, the patients were reexamined after 2 weeks or even for a longer period.

RESULTS

Tissue samples suitable for histologic diagnosis were obtained in 94% of the biopsies. In 17 of 77 patients, changes were observed in the color and pulsed Doppler examination immediately after the biopsy. A small localized flow disturbance was diagnosed in 10 kidneys, and a color tract was seen in 7. In 1 case, this tract was associated with a small localized flow disturbance. In 2 other patients, a localized flow disturbance was detected only in the examination performed 24 hours after the biopsy. Eight of the 10 flow disturbances diagnosed immediately after the biopsy and all tracts were not visible at the 24-hour follow-up examination. All these vascular findings were undetectable on sonographic examination without color and pulsed Doppler imaging.

CONCLUSIONS

The results indicate that vascular lesions, detectable with color and pulsed Doppler sonography, are not rare findings early after renal biopsies. These vascular findings show a high rate of spontaneous resolution within the first 24 hours.

The renal sinus: pathologic spectrum and multimodality imaging approach

Various pathologic conditions can occur in the renal sinus, primarily originating in the constituents of the renal sinus, and the renal sinus can be secondarily involved by surrounding renal parenchymal and adjacent retroperitoneal lesions. Lipomatosis and cysts are common renal sinus lesions with little clinical significance, but differentiation from other pathologic conditions is important. Renal vascular lesions such as renal artery aneurysm or arteriovenous fistula can mimic other parapelvic or peripelvic lesions at excretory urography, but their vascular nature is evident at color Doppler ultrasonography, contrast material-enhanced computed tomography (CT), and magnetic resonance (MR) imaging. Although most tumors originating in the renal pelvis are transitional cell carcinoma or squamous cell carcinoma, renal parenchymal tumors such as renal cell carcinoma or benign multilocular cystic nephroma have a tendency to grow into the renal sinus. Rare tumors of mesenchymal origin can develop in the renal sinus, but their imaging findings are nonspecific. The observation of renal sinus fat is important for detecting a small tumor located in that area and determining the exact tumor stage. Multiplanar CT or MR images can allow exact evaluation of the extent of complex renal sinus disease.

[Diagnostic imaging of peripheral renal vascular disorders]

Peripheral vascular disorders of the kidney involve the intrarenal branches of the renal vascular tree. It include occlusive (infarction and cortical necrosis) and non-occlusive vascular lesions (acquired arteriovenous fistulas, arteriovenous malformation, false aneurysms and microaneurysms). Initial diagnosis relies on color Doppler US and CT angiography. Angiography plays a therapeutic role. MR imaging provides useful diagnostic information on perfusion disorders especially in patients with renal insufficiency.

The role of renal scintigraphy in renal arteriovenous malformation treated by transcatheter arterial embolization

A 41-year-old woman was hospitalized because of gross hematuria. She was found to have a renal arteriovenous malformation and was treated with transcatheter arterial embolization (TAE). Renal scintigraphy with Tc-99m mercaptoacetyltriglycine was performed before and after TAE. Renal scintigraphy was useful for evaluating renal function in this patient.

Staged endovascular occlusion of giant idiopathic renal arteriovenous fistula with platinum microcoils and silk suture threads

Large symptomatic aneurysmal renal arteriovenous (AV) fistulas usually present with a flank bruit, uncontrolled hypertension, and high-output cardiac failure. Traditionally, these have been treated surgically because of the risk of inadvertent pulmonary embolism with use of embolization techniques. The authors report a case of a giant renal AV fistula successfully treated with staged embolization with use of metallic coils and silk suture. This resulted in a graded reduction in the extreme flow through the fistula, followed by delayed thrombosis and cure of the patient's symptoms.

Cirsoid arteriovenous malformation of kidney presenting as a mass suggestive of malignancy

This paper reports a rare case of cirsoid renal arteriovenous malformation (AVM) that showed radiological characteristics of a renal malignancy. Using only conventional procedures such as computerized tomography, the present case was misdiagnosed as a solid tumor mass and therefore radical nephrectomy was indicated. Angiographic analysis is expected to improve the accuracy of diagnosis of AVM, thus reducing the need to resort to invasive techniques.

Intrarenal Doppler findings of upstream renal artery stenosis: a preliminary report

To diagnose 60% or greater diameter-reducing stenosis of the renal artery (RAS), color Doppler imaging (CDI) and angiography were performed on 44 hypertensive and 16 normotensive cases. In this prospective, double-blind study we evaluated the related intrarenal waveform changes. In both the right and left kidneys of normotensive cases, at the level of interlobar arteries, the results indicated a symmetric finding in peak systolic/end diastolic velocities (S/D), pulsatility index (PI) and resistive index (RI) ratios. The results in the stenotic kidneys among the hypertensive group indicated that index values were significantly lower in the stenotic kidneys than those of the contralateral kidneys, the kidneys of control and nonstenotic hypertensive cases. To quantify this observation we suggest "perfusion indexes," which require more studies on a greater number of hypertensive cases. It was concluded that measuring the index values of intrarenal arterial waveforms is easier and more accessible in diagnosing RAS than obtaining those of the main renal artery.