Stefano Cernic

Value of contrast-enhanced ultrasonography for detecting renal infarcts proven by contrast enhanced CT. A feasibility study

The effectiveness of contrast-enhanced ultrasonography (CEUS) in the evaluation of patients with acute renal infarcts was investigated, using contrast-enhanced helical computed tomography (CT) as the reference imaging procedure. Twenty-seven consecutive patients with acute renal infarcts detected with contrast-enhanced helical CT underwent CEUS. Digital cine-clips of CEUS were evaluated by two independent readers blinded to CT findings. Image quality was rated subjectively on a four-point scale. Then, readers were asked to assign a confidence level in diagnosis of renal infarct at the upper pole, medium portion, and lower pole of each kidney according to a five-degree scale, ranging from definitely absent to definitely present. ROC curve analysis was employed to assess the overall confidence of diagnosis of infarct, and weighted kappa values were calculated to assess inter-reader agreement. The subjective image quality of CEUS was lower than the image quality of CT at the upper poles. However, the diagnostic performance of CEUS was excellent (area under receiver-operator characteristic curve 0.992 ± 0.006 for reader 1; 0.991 ± 0.007 for reader 2), with very good inter-reader agreement (weighted kappa value = 0.83). CEUS is a reproducible tool to detect acute renal infarcts in men, with a diagnostic performance approaching that of CT.

The Value of Digital Tomosynthesis in the Diagnosis of Suspected Pulmonary Lesions on Chest Radiography: Analysis of Diagnostic Accuracy and Confidence

RATIONALE AND OBJECTIVES The aim of this study was to investigate the value of digital tomosynthesis in the diagnosis of suspected pulmonary lesions on chest radiography. MATERIALS AND METHODS Two-hundred twenty-eight patients (133 men, 95 women; mean age, 70.8 ± 11.1 years) with suspected pulmonary lesions after initial analysis of chest radiography underwent digital tomosynthesis. Two independent readers (with 3 and 20 years of experience) prospectively analyzed the chest radiographic and digital tomosynthesis images on a picture archiving and communication system workstation and proposed a diagnostic confidence score for each lesion (1 or 2 = definitely or probably extrapulmonary lesion or pseudolesion, 3 = indeterminate, 4 or 5 = probably or definitely pulmonary lesion). Chest computed tomography was the reference standard examination. RESULTS A total of 251 suspected pulmonary lesions were identified. In 71 patients, digital tomosynthesis and computed tomography did not confirm any lesion. In the remaining 157 patients, 180 lesions were identified, including 112 pulmonary and 68 extrapulmonary lesions. In 110 (reader 1) and 123 (reader 2) lesions, correct diagnoses were provided after analysis of the chest radiographs. All lesions were correctly classified after digital tomosynthesis except for 14 extrapulmonary lesions (both readers) that were misinterpreted as pulmonary and 10 (reader 1) and six (reader 2) pulmonary lesions that were misinterpreted as pleural. Digital radiography versus tomosynthesis differed in accuracy (reader 1, 43% vs 90%; reader 2, 49% vs 92%; P < .05) and confidence by area under the receiver-operating characteristic curve (reader 1, 0.788 vs 0.944; reader 2, 0.840 vs 0.997; P < .05). CONCLUSIONS Digital tomosynthesis improved diagnostic accuracy and confidence in the diagnosis of suspected pulmonary lesions on chest radiography.

Original investigationThe Value of Digital Tomosynthesis in the Diagnosis of Suspected Pulmonary Lesions on Chest Radiography: Analysis of Diagnostic Accuracy and Confidence

RATIONALE AND OBJECTIVES The aim of this study was to investigate the value of digital tomosynthesis in the diagnosis of suspected pulmonary lesions on chest radiography. MATERIALS AND METHODS Two-hundred twenty-eight patients (133 men, 95 women; mean age, 70.8 ± 11.1 years) with suspected pulmonary lesions after initial analysis of chest radiography underwent digital tomosynthesis. Two independent readers (with 3 and 20 years of experience) prospectively analyzed the chest radiographic and digital tomosynthesis images on a picture archiving and communication system workstation and proposed a diagnostic confidence score for each lesion (1 or 2 = definitely or probably extrapulmonary lesion or pseudolesion, 3 = indeterminate, 4 or 5 = probably or definitely pulmonary lesion). Chest computed tomography was the reference standard examination. RESULTS A total of 251 suspected pulmonary lesions were identified. In 71 patients, digital tomosynthesis and computed tomography did not confirm any lesion. In the remaining 157 patients, 180 lesions were identified, including 112 pulmonary and 68 extrapulmonary lesions. In 110 (reader 1) and 123 (reader 2) lesions, correct diagnoses were provided after analysis of the chest radiographs. All lesions were correctly classified after digital tomosynthesis except for 14 extrapulmonary lesions (both readers) that were misinterpreted as pulmonary and 10 (reader 1) and six (reader 2) pulmonary lesions that were misinterpreted as pleural. Digital radiography versus tomosynthesis differed in accuracy (reader 1, 43% vs 90%; reader 2, 49% vs 92%; P < .05) and confidence by area under the receiver-operating characteristic curve (reader 1, 0.788 vs 0.944; reader 2, 0.840 vs 0.997; P < .05). CONCLUSIONS Digital tomosynthesis improved diagnostic accuracy and confidence in the diagnosis of suspected pulmonary lesions on chest radiography.

Analysis of different contrast enhancement patterns after microbubble-based contrast agent injection in liver hemangiomas with atypical appearance on baseline scan.

BackgroundWe describe different possible enhancement patterns in liver hemangiomas with atypical appearance on baseline ultrasound after microbubble-based contrast agent injection.MethodsFrom a series of 253 consecutive lesions that were indeterminate on baseline ultrasound and then scanned after injection of air-filled microbubble contrast agent, 65 focal liver lesions were retrospectively selected on the basis of a diagnosis of liver hemangioma on multiphase contrast-enhanced computed tomography (n = 23), magnetic resonance imaging (n = 27), or histology (n = 15). Each lesion was scanned during arterial phase (30 s after microbubble injection) and late phase (5 min after injection). On-site sonologists performed retrospective assessment of contrast-enhancement patterns by consensus.ResultsCentripetal fill-in preceded (n = 50) or not preceded (n = 3) by peripheral nodular/rim-like enhancement was the prevalently observed contrast-enhancement pattern, equivalent to the typical enhancement pattern of liver hemangiomas on contrast-enhanced computed tomography or magnetic resonance imaging. In the remaining lesions, additional enhancement patterns (diffuse contrast enhancement with rapid fill-in and a late hyper-isoechoic appearance, n = 6; peripheral nodular enhancement with a late hypoechoic appearance, n = 3; or persistent heterogeneous and hyperechoic appearance, n = 3) were observed.ConclusionDifferent contrast-enhancement patterns are possible in atypical liver hemangiomas after microbubble injection. Typical centripetal fill-in is the prevalent pattern and its evidence allows diagnosis.

Comparison of Visual and Quantitative Analysis for Characterization of Insonated Liver Tumors After Microbubble Contrast Injection

OBJECTIVE The objective of our study was to compare diagnostic performance of visual and quantitative analysis for the characterization of liver tumors insonated at low transmit power after microbubble contrast agent injection. SUBJECTS AND METHODS This series comprised 166 liver tumors (1-5 cm in diameter) in 166 patients (99 men, 67 women; mean age +/- SD, 58 +/- 11 years) scanned at low transmit power (mechanical index: 0.1-0.14) after sulfur hexafluoride-filled microbubble injection. Digital cine clips recorded at the arterial phase (10-40 sec after contrast injection) and late phase (100-300 sec) were analyzed to characterize liver tumors as benign or malignant. Visual analysis was performed by three independent blinded reviewers who evaluated enhancement patterns at the arterial phase and subjective tumor conspicuity at the late phase. Quantitative analysis of videotape intensity (VI: gray-scale levels, 0-255) was performed to calculate objective tumor conspicuity at the late phase: (VI(tumor) - VI(liver)) / VI(liver). RESULTS Characteristic enhancement patterns were observed in malignant tumors (peripheral rimlike) and benign tumors (peripheral nodular or central and spoke-wheel-shaped). Malignant (n = 95) versus benign (n = 71) tumors differed for subjective (median value: -1 vs 1, respectively) and objective conspicuity at the late phase (-0.6 vs 0.15, respectively; p = 0.001, Mann-Whitney U test) due to persistent microbubble uptake in benign tumors. Diagnostic performance of visual (odds ratio: reviewer 1 = 4.28, reviewer 2 = 10.18, reviewer 3 = 9.56) and quantitative (odds ratio: 89.33) analyses differed significantly in the characterization of liver tumors (p = 0.01, chi-square test). CONCLUSION Quantitative analysis revealed higher diagnostic performance than visual analysis to characterize liver tumors insonated at low transmit power after microbubble contrast agent injection.

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.

64-Slice CT urography: 30 months of clinical experience

PurposeThis study sought to assess the diagnostic accuracy of 64-slice computed tomography urography (CTU) in evaluation of the urinary tract.Materials and methodsA total of 322 CTU procedures were carried out in 317 consecutive patients (mean age 64.4 years). The findings were compared with previous and subsequent patient workup considering both laboratory and imaging studies, such as urine cytology, abdominal ultrasound and CT, cystoscopy, retrograde pyelography, surgery and pathology.ResultsOut of 322 CTU examinations, 169 showed significant urinary tract changes, whereas 153 revealed no urinary disease, in good agreement with the follow-up. In particular, in bladder evaluation, for which we have a direct comparison with cystoscopy in 125 patients, we calculated a CTU sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy of 85%, 94%, 92%, 89% and 90%, respectively.ConclusionsCTU was accurate for urinary tract evaluation, but it cannot replace cystoscopy in patients in whom a malignant bladder disease is suspected.RiassuntoObiettivoScopo del nostro lavoro è stato valutare l’accuratezza diagnostica dell’uro-tomografia computerizzata (TC) eseguita con apparecchiatura a 64 strati nella valutazione delle patologie della via escretrice.Materiali e metodiSono stati effettuati 322 esami uro-TC su 317 pazienti consecutivi (età media 64,6 anni). L’esito è stato confrontato con il precedente e successivo iter diagnostico seguito dal paziente, tenendo in considerazione sia gli esami laboratoristici e strumentali, quali citologia urinaria, ecografia e TC addominale, cistoscopia, cistouretrografia retrograda, sia gli eventuali interventi chirurgici con relativa diagnosi istologica.RisultatiTra le 322 uro-TC eseguite, 169 hanno individuato significative alterazioni a carico dell’apparato urinario e 153 non hanno evidenziato aspetti di rilievo, con buona concordanza al follow-up. In particolare a livello vescicale, ove possediamo in 125 pazienti un riscontro diretto dei reperti mediante cistoscopia, abbiamo rilevato un valore di sensibilità dell’85%, una specificità del 94%, un valore predittivo positivo del 92%, un valore predittivo negativo dell’89%, per una accuratezza diagnostica del 90%.ConclusioniL’uro-TC si è dimostrata un esame accurato per lo studio della via escretrice, ma non può sostituirsi all’esecuzione di un esame cistoscopico nello studio dei pazienti con sospetta patologia neoplastica vescicale.

64-Slice CT urography: optimisation of radiation dose

PurposeThis study assessed means by which to optimise 64-slice computed tomography urography (CTU) in evaluating the urinary tract, with a view to obtaining the best trade-off between image quality and radiation dose.Materials and methodsImage quality was analysed in terms of spatial and contrast resolution on several scans of a phantom performed with automatic dose modulation and different reconstruction kernels and accepted noise level. Data were compared with the radiation dose values recorded for 52 patients who underwent CTU examination.ResultsRadiation dose and image quality differed considerably depending on the reconstruction parameters, even though a higher dose did not always imply better image definition. Data obtained in the phantom were consistent with those obtained in patients. Depending on the clinical problem, the radiation dose varied from 6.2 to 17.6 mSv.ConclusionsCTU cannot be considered a standard examination: the scan parameters need to be adapted to the image quality required for the specific clinical problem.RiassuntoObiettivoLo scopo del nostro lavoro è stato ottimizzare l’uro-tomografia computerizzata (TC) eseguita mediante apparecchiatura a 64 strati nello studio delle patologie della via escretrice per ottenere il miglior rapporto fra qualità di immagine e dose di esposizione.Materiali e metodiÈ stata analizzata la qualità di immagine in termini di risoluzione spaziale e di contrasto di diverse scansioni su fantoccio, ripetute con modulazione automatica di dose, variando il filtro di ricostruzione e il livello di rumore accettato; sono stati valutati i valori di esposizione e confrontato l’esito con quanto osservato in 52 pazienti sottoposti ad esame uro-TC.RisultatiLa dose di esposizione e la qualità d’immagine variano notevolmente modificando i parametri di ricostruzione, sebbene non sempre l’aumento di dose comporti un reale vantaggio in termini di definizione d’immagine. La variazione osservata su fantoccio è coerente con i risultati ottenuti nei pazienti esaminati. In base al quesito diagnostico l’esame ha comportato nei pazienti un’esposizione variabile da 6,2 a 17,6 mSv.ConclusioniL’uro-TC non può essere considerato un esame standardizzato: i parametri di scansione devono essere sempre valutati e modulati in base alla qualità di immagine richiesta dallo specifico problema clinico.

Color Doppler sonography of intrahepatic vascular shunts

To illustrate the sonographic and Doppler features of the different types of intrahepatic vascular shunts.