F. Pozzi Mucelli

Comparison between 64-row CT angiography and digital subtraction angiography in the study of lower extremities: personal experience

PurposeThis study was undertaken to evaluate the potential of 64-row multislice computed tomography (CT) versus digital subtraction angiography (DSA) in detecting significant lesions of lower-extremity inflow and runoff arteries.Materials and methodsFifty-three patients underwent 64-row multislice CT and DSA over a mean of 36 days. The vascular tree was divided into 33 segments. Three readers independently reviewed the axial CT scans and multiplanar oblique and two- and three-dimensional reconstructions (maximum intensity projection and volume rendering) images to assess degree of stenosis according to four categories: 1 (0%–49% stenosis); 2 (50%–99% stenosis); 3 (occluded); 4 (not evaluable). In all cases, DSA was performed by arterial catheterisation.ResultsIn 53 patients, 1,440 segments were evaluated (infrarenal aorta and 16 arterial segments for each leg; 42 bilateral studies, 11 unilateral studies). Compared with DSA, CT angiography yielded 97.2% sensitivity, 97% specificity, 92.5% positive predictive value, 98.9% negative predictive value, 97.1% diagnostic accuracy and 95.4% concordance on the degree of stenosis.ConclusionsSixty-four-row multislice CT proved to be helpful in detecting haemodynamically significant lesions in peripheral arterial occlusive disease and improved the results obtained with 4- and 16-slice multidetector CT. In addition, owing to the high spatial resolution and rigorous technique, no variations in the data obtained below the knee were detected, overcoming a limitation of earlier generations of CT scanners.RiassuntoObiettiviScopo del nostro lavoro è stato valutare le potenzialità dell’angio-tomografia computerizzata (TC) a 64 strati nella valutazione dell’arteriopatia ostruttiva degli arti inferiori (AOAI) vs l’angiografia digitale.Materiali e metodiCinquantatre pazienti sono stati sottoposti ad angio-TC a 64 strati e angiografia digitale in un intervallo medio di tempo di 36 giorni. L’albero vascolare è stato suddiviso in 33 segmenti. Tre radiologi hanno valutato le immagini assiali e le ricostruzioni multiplanari oblique e bi-tridimensionali (maximum intensity projection [MIP], volume rendering [VR]), e hanno classificato le lesioni in 4 gradi: 1=stenosi 0%–49%, 2=stenosi 50%–99%, 3=occlusione, 4=non valutabile. Gli esami di angiografia digitale sono stati eseguiti sempre mediante cateterismo arterioso.RisultatiNei 53 pazienti sono risultati valutabili 1440 segmenti (aorta sottorenale e 16 segmenti/arto; 42 studi bilaterali; 11 studi monolaterali). Nei confronti dell’angiografia, l’angio-TC ha dimostrato sensibilità=97,2%, specificità=97%, valore predittivo positivo=92,5%, valore predittivo negativo=98,9%, accuratezza diagnostica=97,1%, concordanza grado di stenosi=95,4%.ConclusioniL’angio-TC a 64 strati si è dimostrata affidabile nella valutazione delle lesioni steno-ostruttive dell’AOAI ed è stata in grado di migliorare ulteriormente i risultati ottenuti con TC a 4–16 strati. Inoltre, grazie all’elevata risoluzione spaziale e ad una tecnica rigorosa, non sono stati rilevate variazioni nei dati ottenuti al di sotto del ginocchio, superando un limite delle TC delle generazioni precedenti.

Renal artery stenosis: Comparative evaluation of gadolinium-enhanced MRA and DSA

PurposeThis study was undertaken to evaluate the accuracy of contrast-enhanced magnetic resonance angiography (CE-MRA) in detecting renal artery stenosis using intra-arterial digital subtraction angiography (DSA) as the gold standard.Materials and methodsThirty-five consecutive patients with possible renovascular hypertension were prospectively studied; 26 of them underwent both MRA and DSA. In these 26 cases, two readers assessed the number of renal arteries, the presence of stenoses and their degree. Results were compared with DSA, and sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy of MRA were determined. Interobserver variability was also calculated.ResultsDSA showed 51 main renal arteries (one patient had a single kidney) and six accessory arteries (total number of arteries 57) in the 26 patients considered. Both MRA readers detected all of the 51 main renal arteries and only one accessory vessel. When the presence of stenosis was considered, the readers’ results, respectively, were as follows: sensitivity 77% and 72%, specificity 69% and 69%, PPV 86% and 85%, NPV 55% and 50% and diagnostic accuracy 75% and 71%. When the detection of significant stenosis was considered, the results, respectively, were: sensitivity 83% and 83%, specificity 73% and 78%, PPV 60% and 65%, NPV 90% and 91%, and diagnostic accuracy 76% and 80%. Interobserver variation was good when considering stenosis detection (κ=0.69) and excellent when considering detection of significant stenosis (κ=0.85).ConclusionsMRA results do not appear as positive as in the majority of papers in the literature. Multiple reasons can probably be invoked to explain this difference. The mean age of our patients, higher than in many other studies, should be noted and may have accounted for their possible poor cooperation. Moreover, all of the missed significant stenoses were distally located, and therefore, the failure to detect them might be related to the suboptimal spatial resolution of MRA. Nevertheless, MRA showed a high NPV for detecting significant stenoses, a finding of considerable clinical relevance in that it allows patients with normal MRA findings to be spared additional more invasive procedures.RiassuntoObiettivoValutare l’faccuratezza diagnostica della angio-RM dopo somministrazione di gadolinio nella identificazione di stenosi dell’farteria renale avendo l’fangiografia digitale per via arteriosa quale gold standard.Materiali e metodiSono stati valutati prospetticamente 35 pazienti consecutivi con sospetto di ipertensione nefrovascolare, 26 dei quali sottoposti ad angio-RM e ad angiografia digitale. Due lettori hanno valutato in questi 26 casi il numero di arterie renali, la presenza di eventuali stenosi e il grado delle stenosi. I risultati sono stati raffrontati a quelli dell’fangiografia per valutare sensibilità, sensibilità, valore predittivo positivo (VPP) e negativo (VPN) e accuratezza diagnostica dell’fangio-RM. È stata inoltre calcolata la variabilità interosservatore.RisultatiNei 26 pazienti esaminati, l’fangiografia ha rilevato 51 arterie renali principali (1 monorene) e 6 polari, per un totale di 57 arterie. Entrambi i lettori degli esami angio-RM hanno identificato le 51 arterie principali ed 1 sola polare. I due lettori hanno fatto registrare, considerando la presenza di stenosi, una sensibilità del 77%/72%, una sensibilità del 69%/69%, un VPP dell’f86%/85%, un VPN del 55%/50% e un’accuratezza diagnostica del 75%/71%, rispettivamente. Quando si consideri invece la presenza di stenosi emodinamicamente significativa i risultati ottenuti erano i seguenti: sensibilità 83%/83%, sensificità 73%/78%, VPP 60%/65%, VPN 90%/91%, accuratezza diagnostica 76%/80%. La concordanza interosservatore risultava buona per la presenza di stenosi (κ=0,69) e eccellente per la presenza di stenosi significativa (κ=0,85).ConclusioniI risultati ottenuti appaiono inferiori a quelli riportati dalla maggior parte dei lavori in letteratura. La spiegazione non appare univoca, ma va rilevata in particolare l’età media dei pazienti indagati, superiore a quella riportata dalla maggior parte degli altri autori, che potrebbe aver giustificato una minor collaborazione dei pazienti, e la sede distale delle stenosi emodinamicamente significative non identificate, il cui mancato riconoscimento potrebbe essere legato alla risoluzione spaziale non ottimale dell’angio-RM. Va comunque rilevato che l’angio-RM ha dimostrato un elevato valore predittivo negativo per la presenza di stenosi significativa, aspetto di particolare rilievo clinico in quanto ciò permette ai pazienti con angio RM renale normale di evitare ulteriori indagini più invasive.

“Aggressive” Renal Angiomyolipoma

Purpose: We describe the US and CT examinations of 4 patients with renal angiomyolipoma with an “aggressive” appearance, and review the literature. Material and Methods: The imaging findings in 4 patients with benign renal angiomyolipomas associated with thrombosis of the renal vein and/or inferior vena cava are presented. In one case, enlarged lymph nodes at the renal hilum were found. Results: CT demonstrated fat densities within both tumor and thrombus. In one patient, small lymph nodes with low density internal areas were detected in the para-aortic region. When considering our patients together with those reported in the literature, we found that most angiomyolipomas with venous invasion were large and centrally located within the kidney. Venous thrombosis was observed in 9 lesions of the right kidney, and in only 4 of the left one; detection of the site of origin was impossible in one case. One patient only had symptoms due to the thrombus; 10 had problems due to the tumor; and 3 were asymptomatic. Only 4 patients with pararenal enlarged lymph nodes have been reported on in the imaging literature. Fat-containing nodes were detected by CT in one case only; the others had enlarged nodes of soft-tissue density. In one patient the diagnosis of hamartomatous lymph node invasion was established by angiography. Conclusion: In patients with renal angiomyolipoma, demonstration of both fatty thrombus and the fatty infiltration of lymph nodes of the renal hilum cannot be regarded as an indication of malignancy, but only of local aggressive behavior. Although surgery is commonly contemplated to prevent symptoms from venous thrombosis, conservative treatment seems possible. Detection of enlarged lymph nodes of soft tissue density may cause difficult diagnostic problems, with the diagnosis addressed only by the presence of associated lesions. Increased awareness that renal angiomyolipoma can sometimes appear “aggressive” could help to prevent such lesions from being considered malignant, and thus avoid surgical confirmation of their nature.

Three-dimensional reconstructions of carotid bifurcation from CT images: evaluation of different rendering methods

Three-dimensional computed tomographic angiography (3D-CTA) and digital substraction angiography of the cerval caratid artery were performed bilaterally in 15 patients with suspected stenoses. A new semi-automatic segmentation and new rendering methods were used. The degree of stenosis of internal carotid arteries, as determined both by axial slices and 3D images (surface, integral, maximum-intensity-projection, and raysum-rendered images), was compared qualitatively and quantitatively to angiographic findings. In correlation to angiography, the accuracy in determining the stenosis classification of internal carotid arteries was of 97% for axial slices and 59–90% for 3D images, respectively. Raysum (pseudoradiograph) rendering was found to be the most reliable rendering method and gave the most similar results to angiography. The accuracy of all rendering methods was improved by applying calcification removing algorithm, with a statistically significant difference between surface rendering without plaque removal and raysum rendering using theremoving algorithm.

Endovascular treatment of endoleaks after endovascular abdominal aortic aneurysm repair: personal experience

AbstractPurpose.This paper describes the different endovascular treatments (cuffs, endografts and embolisation) available for types I, II and III endoleaks occurring after endovascular abdominal aortic aneurysm repair (EVAR).Materials and methods.From January 2000 to June 2006, 134 patients (118 men, 16 women; mean age 75.1 years) underwent EVAR. Ten patients (7%) developed significant endoleaks requiring endovascular treatment.Results.Five endoleaks were type I, two were type II and three were type III. Of the five type I endoleaks, four were proximal and one was distal. The proximal endoleaks were treated by cuff deployment, whereas the distal endoleak was treated with a bifurcated graft. Of the two patients with type II endoleak, one was treated by translumbar puncture and coil embolisation, and the other was treated by superselective embolisation of the lumbar feeding vessel with nonresorbable particles. Of the three patients with type III endoleak, two were treated by deploying an aortouniiliac endograft inside the bifurcated graft and the other by implanting a cuff to restore continuity between the graft body and the contralateral limb. Endovascular treatment was successful in 6/10 cases, whereas three cases required surgical conversion. One patient did not undergo surgery owing to poor general condition.Conclusions.The reported incidence of endoleaks after EVAR is 10%–20%. Significant endoleaks should be treated promptly. Endovascular treatment can be done with different techniques, but success in not constant due to adverse anatomical conditions and technical difficulties.

Prevalence of extravascular collateral findings during 64-slice CT angiography of the abdominal aorta and lower limbs

PurposeThe aim of this study was to assess the prevalence of extravascular collateral findings during 64-slice CT angiography of the abdominal aorta (AA-CTA) and lower limbs (LL-CTA).Materials and methodsThe images of 536 AA-CTA and LL-CTA examinations performed for suspected aortic and peripheral vascular disease in 500 patients were retrospectively reviewed. Two radiologists evaluated the 5-mm axial images independently using appropriate window settings for the area under investigation. Collateral findings were divided according to their clinical significance into significant, nonsignificant and meriting further investigation.ResultsNo collateral findings were identified in 97/500 patients (19.4%). In the remaining patients, 821 collateral findings were detected, of which 43 (5.24%) were classified as significant, 135 (16.44%) as meriting further investigation and 643 (78.32%) as nonsignificant. The findings indicative of the presence of a malignant lesion totalled 36 (4.5%).ConclusionsAA-CTA and LL-CTA demonstrate a nonnegligible prevalence of collateral findings, many of them major. It therefore appears that the evaluation should focus not only on the image reconstructions to identify vascular disease, but also on the native axial images to detect incidental findings.RiassuntoObiettivoScopo di questo studio è quello di valutare la prevalenza dei reperti collaterali extravascolari in corso di indagini di angio-TC dell’aorta addominale (AA-CTA) e degli arti inferiori (AI-CTA).Materiali e metodiSono state valutate retrospettivamente le immagini di 500 pazienti sottoposti ad AA-CTA e AI-CTA, per un totale di 536 esami, mediante apparecchiatura a 64 strati per sospetta patologia vascolare aortica e periferica. Due radiologi hanno valutato separatamente le immagini assiali a 5 mm utilizzando finestre di vista adeguate al distretto valutato. I reperti collaterali sono stati divisi a seconda della loro rilevanza clinica in significativi, non significativi e meritevoli di approfondimento.RisultatiSu 500 pazienti, solo in 97 non sono stati riscontrati reperti collaterali (19,4%); sono stati identificati 821 reperti accessori, dei quali 43 (5,24%) sono stati reputati significativi; 135 (16,44%) meritevoli di approfondimento e 643 (78,32%) non significativi. I reperti suggestivi per la presenza di una lesione neoplastica sono stati 36 (4,5%).ConclusioniGli esami di angio-TC addominali e degli arti inferiori presentano una prevalenza di reperti collaterali anche maggiori non trascurabile. Appare quindi necessario effettuare una valutazione dei reperti accessori sulle immagini assiali native, senza limitarsi alla sola valutazione delle ricostruzioni focalizzate alla valutazione vascolare.

Virtual angioscopy by means of three-dimensional rotational angiography of the aortoiliac arteries

AbstractPurpose.The aim of this study was to report the different findings that can be visualised with virtual angioscopy starting from rotational angiography (RA) and three-dimensional (3D) image processing (3DRA) in the evaluation of the abdominal aorta and iliac arteries.Materials and methods.Fifty-seven patients showing an occlusive or aneurysmal disease of the abdominal aorta and iliac arteries underwent intraarterial digital subtraction angiography (DSA) equipped with the RA function and a 3D workstation. We found that 3DRA is able to generate images of the examined vessels with a very effective 3D appearance; furthermore, it is able to create images of the lumen and wall of the vessel through two different modalities: endoviews and cross sections. The possibility of matching high-density structures (i.e. calcified plaques and stents) to standard 3D reconstructions of the examined arteries was applied.Results.Different aspects of the arteries can be demonstrated in the angioscopic elaborations: the normal and stenotic lumen, artery bifurcations, the collateral vessel origins and the severity and extensions of atheromatous calcifications and their relationships to the vessel wall. Virtual angioscopy is able to visualise some devices (catheters, stents) introduced during diagnostic and interventional procedures.Conclusions.The constant technological evolution of diagnostic imaging is offering new image-processing techniques, providing new types of previously unexplored information. We present a summary of the different radiological findings that can be demonstrated with this new imaging technique.

Visceral Trauma: Diagnostic Imaging and Interventional Radiology

In clinical practice, physical examination is often unreliable in patients who are sedated, intoxicated, paralyzed, have head injures, or otherwise are unable to communicate symptoms. Moreover, intra-abdominal injury in particular can be present in the absence of signs and symptoms in blunt trauma patients. So for an accurate evaluation of the patient with multiple trauma the utilization of diagnostic modalities is often required. Three diagnostic imaging tools are utilized for the evaluation of thoraco-abdominal visceral trauma: standard X-ray plain film, ultrasonography (US), and computed tomography (CT). Furthermore, we must remember that in the last 10 years interventional radiology has been shown to be able to contribute to the treatment of these conditions due to its low invasiveness.

Ultrasound Examination of Fluid Complex Abdominal Lesions and Correlation with Computed Tomography

Ultrasound (US) and computed tomography (CT) criteria for “solid” and “liquid” abdominal lesions are well established and have long been codified. Nevertheless, there are a number of lesions which cannot be classified as solid or liquid and which are usually described as complex, either because they tend to show intermediate findings or because they have characteristics of both solid and liquid lesions at the same time. Based upon US and CT criteria there are two fundamental patterns of “complex” lesions [3]