Vittorio Miele

Dual energy CT (DECT) of the liver: conventional versus virtual unenhanced images

ObjectiveTo compare image quality and noise of conventional unenhanced (CU) and virtual unenhanced (VU) images in patients who underwent hepatic dual energy computed tomography (DECT) and to assess potential radiation dose reduction.Materials and methodsForty consecutive patients were studied. Mean CU and VU image quality and noise were analyzed by two blinded radiologists using a five-point grade scale. The effective radiation dose of a triple-phase protocol (CU, arterial and DE portal phases) were compared with that of a dual-phase protocol (arterial and DE portal phases).ResultsNo significant difference in mean image quality was observed between VU (3.92u2009±u20090.85) and CU images (4.20u2009±u20090.72). A significant difference in mean image noise was observed between VU and CU (Pu2009<u20090.01). The dose reduction achieved by omitting the unenhanced acquisition was 30.47u2009±u20097.07% (Pu2009<u20090.01). In 6 patients, a complete VU liver image was not obtained.ConclusionsVU images can be obtained with similar image quality as CU. This approach favors a reduction in patient’s radiation exposure. Nevertheless, a complete abdominal DECT is possible only in patients with a low body mass index, due technical limitations of the present DECT systems.

Blunt abdominal trauma: role of contrast-enhanced ultrasound (CEUS) in the detection and staging of abdominal traumatic lesions compared to US and CE-MDCT.

PurposeThis study was undertaken to evaluate the accuracy of contrast-enhanced ultrasound (CEUS) in the detection and grading of abdominal traumatic lesions in patients with low-energy isolated abdominal trauma in comparison with baseline ultrasound (US) and contrast-enhanced multidetector computed tomography (CE-MDCT), considered the gold standard.Materials and methodsA total of 256 consecutive patients who arrived in our Emergency Department between January 2006 and December 2012 (159 males and 97 females aged 7–82xa0years; mean age 41xa0years), with a history of low-energy isolated abdominal trauma were retrospectively analysed. All patients underwent US, CEUS with the use of a second-generation contrast agent (Sonovue, Bracco, Milan, Italy) and MDCT. Sensitivity, specificity, positive and negative predictive values (PPV and NPV) and overall accuracy for the detection of lesions and free peritoneal fluid on US and CEUS, and sensitivity for the grading of lesions on CEUS were calculated compared with the CT findings, in accordance with the American Association for the Surgery of Trauma criteria.ResultsCE-MDCT identified 84 abdominal traumatic lesions (liverxa0=xa028, spleenxa0=xa035, kidneyxa0=xa021) and 45 cases of free intraperitoneal fluid. US depicted 50/84 traumatic lesions and 41/45 cases of free peritoneal fluid; CEUS identified 81/84 traumatic lesions and 41/45 free peritoneal fluid. The sensitivity, specificity, PPV, NPV and overall accuracy for the identification of traumatic abdominal lesions were 59, 99, 98, 83 and 86xa0%, respectively, for US and 96, 99, 98, 98 and 98xa0%, respectively, for CEUS. The values for the identification of haemoperitoneum were 91, 99, 95, 98 and 97xa0%, respectively, for US and 95, 99, 95, 99 and 98xa0%, respectively, for CEUS. CEUS successfully staged 72/81 traumatic lesions with a sensitivity of 88xa0%.ConclusionsIn patients with low-energy isolated abdominal trauma US should be replaced by CEUS as the first-line approach, as it shows a high sensitivity both in lesion detection and grading. CE-MDCT must always be performed in CEUS-positive patients to exclude active bleeding and urinomas.

Accuracy of contrast-enhanced ultrasound (CEUS) in the identification and characterization of traumatic solid organ lesions in children: a retrospective comparison with baseline US and CE-MDCT

IntroductionLocalized low-energy abdominal trauma is very frequent in the pediatric population. The findings of several studies have shown that ultrasonography (US) can represent a useful and cost-effective tool in the evaluation of blunt abdominal trauma both in adults and children. However, many parenchymal injuries are not correctly visualized at baseline US examination. The introduction of specific US contrast agents contrast-enhanced ultrasound (CEUS) has enabled a better identification of traumatic organ injuries. The correct use of CEUS could therefore identify and select the children who need further diagnostic investigation computed tomography (CT), avoiding unnecessary radiation and iodinated contrast medium exposure. The purpose of our study was to assess the sensibility and feasibility of CEUS in the assessment of low-energy abdominal trauma compared to baseline US in pediatric patients, using contrast-enhanced MDCT as the reference standard.Materials and methodsWe retrospectively reviewed 73 children (51 M and 22 F; mean age 8.7xa0±xa02.8xa0years) who presented in our Emergency Department between October 2012 and October 2013, with history of minor abdominal trauma according to the Abbreviated Injury Scale and who underwent US, CEUS, and CE-MDCT. Inclusion criteria were: male or female, aged 0–16, hemodynamically stable patients with a history of minor blunt abdominal trauma. Exclusion criteria were adulthood, hemodynamical instability, history of major trauma. Sensitivity, specificity, PPV, NPV, and accuracy were determined for US and CEUS compared to MDCT.Results6/73 patients were negative at US, CEUS, and MDCT for the presence of organ injuries. In the remaining 67 patients, US depicted 26/67 parenchymal lesions. CEUS identified 67/67 patients (67/67) with parenchymal lesions: 21 lesions of the liver (28.8xa0%), 26 lesions of the spleen (35.6xa0%), 7 lesions of right kidney (9.6xa0%), 13 lesions of left kidney. MDCT confirmed all parenchymal lesions (67/67). Thus, the diagnostic performance of CEUS was better than that of US, as sensitivity, specificity, PPV, NPV, and accuracy were 100, 100, 100, 100, and 100xa0% for CEUS and 38.8, 100, 100, 12.8, and 44xa0% for US. In some patients CEUS identified also prognostic factors as parenchymal active bleeding in 8 cases, partial devascularization in 1 case; no cases of vascular bleeding, no cases of urinoma. MDCT confirmed all parenchymal lesions. Parenchymal active bleeding was identified in 16 cases, vascular bleeding in 2 cases, urinoma in 2 cases, partial devascularization in 1 case.ConclusionsCEUS is more sensitive and accurate than baseline US and almost as sensitive as CT in the identification and characterization of solid organs lesions in blunt abdominal trauma. CT is more sensitive and accurate than CEUS in identifying prognostic indicators, as active bleeding and urinoma. CEUS should be considered as a useful tool in the assessment and monitoring of blunt abdominal trauma in children.

First-line sonographic diagnosis of pneumothorax in major trauma: accuracy of e-FAST and comparison with multidetector computed tomography

PurposeCombined clinical examination and supine chest radiography have shown low accuracy in the assessment of pneumothorax in unstable patients with major chest trauma during the primary survey in the emergency room. The aim of our study was to evaluate the diagnostic accuracy of extended-focused assessment with sonography in trauma (e-FAST), in the diagnosis of pneumothorax, compared with the results of multidetector computed tomography (MDCT) and of invasive interventions (thoracostomy tube placement).Materials and methodsThis was a retrospective case series involving 368 consecutive unstable adult patients (273 men and 95 women; average age, 25xa0years; range, 16–68xa0years) admitted to our hospital’s emergency department between January 2011 and December 2012 for major trauma (Injury Severity Scorexa0≥xa015). We evaluated the accuracy of thoracic ultrasound in the detection of pneumothorax compared with the results of MDCT and invasive interventions (thoracostomy tube placement). Institutional review board approval was obtained prior to commencement of this study.ResultsAmong the 736 lung fields included in the study, 87 pneumothoraces were detected with thoracic CT scans (23.6xa0%). e-FAST detected 67/87 and missed 20 pneumothoraces (17 mild, 3 moderate). The diagnostic performance of ultrasound was: sensitivity 77xa0% (74xa0% in 2011 and 80xa0% in 2012), specificity 99.8xa0%, positive predictive value 98.5xa0%, negative predictive value 97xa0%, accuracy 97.2xa0% (67 true positive; 668 true negative; 1 false positive; 20 false negative); 17 missed mild pneumothoraces were not immediately life-threatening (thickness less than 5xa0mm).ConclusionsThoracic ultrasound (e-FAST) is a rapid and accurate first-line, bedside diagnostic modality for the diagnosis of pneumothorax in unstable patients with major chest trauma during the primary survey in the emergency room.

Second-generation sonographic contrast agents in the evaluation of renal trauma

PurposeThe purpose of this study was to define the indications, diagnostic accuracy and limitations of second-generation sonographic contrast agents in the evaluation of patients with renal trauma.Materials and methodsBetween March 2004 and April 2005, 277 patients with blunt abdominal trauma were evaluated. Twenty-eight out of 277 patients had renal lesions, the severity of which was graded according to the organ injury severity scale of the American Association for the Surgery of Trauma (AAST). All the patients enrolled in the study had minor trauma and were evaluated with baseline ultrasound (US), contrast-enhanced US after injection of a second-generation contrast agent (SonoVue) and, if positive, with multiphasic multidetector computed tomography (MDCT).ResultsFive out of 28 traumatic parenchymal lesions with perirenal fluid collection were identified at baseline US. All 28 renal parenchymal lesions, with or without perirenal or retroperitoneal haematoma, were identified at contrast-enhanced US. Multiphase MDCT confirmed all the cases that were positive at contrast-enhanced US and demonstrated the integrity of the urinary tract in the delayed phase.ConclusionsOur experience confirmed the diagnostic accuracy of second-generation sonographic contrast material both for diagnosis and for appropriate patient management. In particular, contrast-enhanced sonography proved to be a reliable technique for the evaluation and follow-up of low-grade renal injuries. Its main advantage is reduced radiation exposure, as fewer MDCT examinations are needed, whereas its limitation is the high cost of the technique if used in unselected patients.RiassuntoObiettivoIdentificare le indicazioni, l’accuratezza diagnostica ed i limiti dell’ecografia con mezzo di contrasto di II generazione nella valutazione del paziente con trauma renale.Materiali e metodiSono stati valutati, tra marzo 2004 ed aprile 2005, 277 pazienti con trauma addominale chiuso. Ventotto/277 pazienti presentavano lesioni renali la cui gravità era stata definita in rapporto all’Injury Severity Scale dell’Associazione Americana per la Chirurgia del Trauma. I pazienti considerati, tutti con trauma minore, sono stati sottoposti ad esame ecografico basale e dopo iniezione di MdC ecografico di II generazione (SonoVue, Bracco) ed ad esame TC multidetettore multifasico in caso di positività.RisultatiCinque/28 lesioni parenchimali traumatiche con raccolta fluida perirenale sono state identificate all’esame ecografico basale. Ventotto/28 lesioni parenchimali renali, con o senza ematoma perirenale o retroperitoneale, sono state identificate all’esame ecografico con MdC. L’esame TC multidetettore multifasico ha confermato tutti i casi positivi all’esame eco-contrastografico ed ha inoltre definito, all’acquisizione tardiva, la situazione della via escretrice urinaria.ConclusioniLa nostra esperienza ha confermato l’accuratezza diagnostica dell’ecografia con MdC di II generazione sia nella diagnosi della lesione che per la corretta gestione del paziente. In modo particolare l’ecografia con MdC risulta tecnica affidabile per la valutazione del trauma renale di basso grado e nel follow-up dello stesso riducendo il ricorso a ripetuti esami TC con riduzione della dose radiante. I limiti sono dati dagli alti costi della tecnica se condotta su popolazione non selezionata.

Diagnostic imaging in pediatric polytrauma management

Trauma is the cause of over 45xa0% of deaths in children aged 1 to 14xa0years. Since multiple injuries are common among children, the emergency physician has to assess all the organs of a high-energy injured child, independent of mechanism of the trauma. Even if the principles of polytrauma management are identical both in children and in adults, the optimal pediatric patient care requires a specific understanding of some important anatomical, physiological, and psychological differences that play a significant role in the assessment and management of a pediatric patient. Emergency Radiology already plays a crucial role in the diagnostic process of a polytraumatized child according to the primary survey, through the use of multiple imaging modalities. Radiological and Ultrasound examinations play a basic role in the hemodynamically unstable patients. In the hemodynamically stable patients whole-body CT scanning is the most immediate radiological procedure that allows the examination of all the body parts of a polytraumatized child, reducing the number of minor injuries that might otherwise be neglected.

The risk of associated urological abnormalities in children with pre and postnatal occasional diagnosis of solitary, small or ectopic kidney: is a complete urological screening always necessary?

ObjectiveVoiding cystourethrogram (VCUG) and radionuclide scan is recommended for patients with solitary (secondary to aplasia or multicystic dysplasia), hypoplasic or single ectopic kidney, to detect associated anomalies (vesicoureteric reflux, obstructive uropathies). With the increase of occasional diagnosis, mainly by fetal ultrasound (US), the possibility of an unjustified extension of diagnostic work up must be prevented. Aim of this paper was to estimate the incidence of associated anomalies in asymptomatic cases without associated US signs of hydronephrosis.Materials and methodsAmong 158 Patients examined there were 81 solitary kidneys (26 multicystic dysplasia), 27 small kidneys, 50 single ectopic kidneys); prenatal diagnosis was recorded in 86%. Incidence of associated anomalies was compared with figures resulting when symptomatic cases or with hydronephrosis were excluded.ResultsVesicoureteral reflux or obstruction were found in 17% of solitary kidneys, 70% of hypoplasic kidneys and 2% of single ectopic kidneys. Among those (120 cases) without infection or hydronephrosis, incidence decreased, respectively to 5, 60 and 0%.ConclusionsAssociated anomalies are reported to affect up to 48% of solitary kidneys and about 30% of single ectopic; 80% of severe reflux are usually associated to small kidneys. In our series of solitary and ectopic kidneys incidence of abnormalities was significantly less and fell to negligible values when occasionally detected, undilated cases were considered. On this basis, indiscriminate urological screening simply based on the occasional pre or postnatal detection of undilated solitary or ectopic kidney appears to be unjustified. Small kidneys deserve special attention and VCUG is always indicated.

Diagnostic imaging of blunt abdominal trauma in pediatric patients

Trauma is a leading cause of morbidity and mortality in childhood, and blunt trauma accounts for 80–90xa0% of abdominal injuries. The mechanism of trauma is quite similar to that of the adults, but there are important physiologic differences between children and adults in this field, such as the smaller blood vessels and the high vasoconstrictive response, leading to the spreading of a non-operative management. The early imaging of children undergoing a low-energy trauma can be performed by CEUS, a valuable diagnostic tool to demonstrate solid organ injuries with almost the same sensitivity of CT scans; nevertheless, as for as urinary tract injuries, MDCT remains still the technique of choice, because of its high sensitivity and accuracy, helping to discriminate between an intra-peritoneal form a retroperitoneal urinary leakage, requiring two different managements. The liver is the most common organ injured in blunt abdominal trauma followed by the spleen. Renal, pancreatic, and bowel injuries are quite rare. In this review we present various imaging findings of blunt abdominal trauma in children.

Comparison between MRI and CEUS in the follow-up of patients with blunt abdominal trauma managed conservatively

IntroductionOver the past two decades, there has been a shift toward non-operative treatment of patients undergoing a solid organ injury, thus requiring an increasing number of imaging studies to monitor the healing of lesions, which were performed by computed tomography (CT). In consideration of the use of ionizing radiation and contrast media, nowadays there is a trend toward the use contrast-enhanced ultrasound (CEUS) in the follow-up of blunt abdominal trauma. However CEUS has some limits, especially in the assessments of small lesions and in the evaluation of urinary tract lesions and vascular complications. Magnetic resonance imaging (MRI) is a useful alternative, since its lack of use of ionizing radiation, its panoramicity, the possibility to avoid contrast media and the ability to properly evaluate even small lesions. The aim of this study is to evaluate the usefulness and the feasibility of MRI in the follow-up of patients with low-grade blunt abdominal trauma.Materials and methodsWe performed a retrospective review of a cohort including 270 consecutive patients with a history of blunt abdominal trauma; among them, 118 underwent a high-energy trauma, and 152 a low-energy trauma. 124 patients had findings of abdominal injuries at the contrast-enhanced multidetector CT (CE-MDCT), including 68 from the group of major trauma and 56 from the group of minor trauma. 39 patients were operated for incoming lesions. The remaining 85 patients were treated conservatively. Eight patients underwent surgery later for delayed bleeding. The remaining 77 underwent the full follow-up protocol. Follow-up protocol included CEUS at 24 and 72xa0h and CEUS and MRI at 1xa0month after trauma; only MRI was performed until the complete resolution.ResultsCEUS at 24-h and at 72-h from trauma showed a very good correlation with onset CE-MDCT in lesions staging. With respect to onset CE-MDCT, CEUS did not identified 2 adrenal injuries and 2 lesions of urinary tract, an intrinsic limit of this technique. CEUS performed at 1xa0month did not show traumatic lesions in 49/77 of patients. In the remaining 28/77 cases, CEUS demonstrated reduction of the size of the lesions ranging from 25 to 50xa0%. MRI performed at 1xa0month from trauma did not show traumatic injuries in 37/77 patients; it demonstrated persistence of organ lesion in 40/77 patients. Therefore, in 12/77 patients MRI performed at 1-month demonstrated the persistence of minimal or moderate organ injury, while CEUS was completely negative. In addition, MRI allowed to enhance the persistence of adrenal lesions in 2 cases and the integrity of urinary tract in 2. In the remaining 28 patients, in which both CEUS and MRI showed disease persistence, MRI, however, allowed a better definition of injury extension with respect to CEUS, in terms of dimensions, edges, and morphological evolution.Discussion and conclusionsMRI allowed to make a better assessment of injuries than CEUS, allowing also a temporal stage of lesions. Infact, there are different evolution stages corresponding to accurate imaging findings. To our knowledge, this is the first study that describes the evolution of blood collection in parenchymal abdominal organs. Therefore, in patients who underwent abdominal traumatic injuries conservatively treated, the follow-up at 1xa0month can be made by MRI, due to its panoramicity and its high contrast resolution, which allow a better morphological and temporal trauma staging respect to the CEUS.

The role of CEUS in the assessment of haemodynamically stable patients with blunt abdominal trauma

Computed tomography (CT) still represents the preferred imaging method in the assessment of patients presenting with multiple trauma. Nevertheless, in patients with low-energy abdominal trauma, the use of CT is debated because of the possible unnecessary radiation exposure. Accordingly, conventional ultrasound (US) imaging has been increasingly employed as the initial imaging modality in the workup of minor traumatic emergency conditions. Focused assessment with sonography for trauma is widely used to detect free intra-abdominal fluid, but its role is controversial, because the absence of free fluid does not exclude the presence of injuries to abdominal organ. Injection of an ultrasound contrast agent (UCA) may give the radiologist relevant additional information to that obtained with conventional US. Thus, in trauma patients, following early assessment with conventional US imaging, a contrast-enhanced US (CEUS) can provide a more reliable evaluation of solid organ injuries and related vascular complications, including active bleeding, pseudoaneurysms, and artero-venous fistulas. CEUS cannot replace abdominal CT, but it represents a noninvasive and repeatable imaging tool capable of providing a reliable assessment of trauma severity and expedite the patient’s treatment.