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Nonostante i continui progressi tecnologici, l’ecografia convenzionale in scala di grigi non presenta elevata specificita nella caratterizzazione delle lesioni focali epatiche [1]. Inoltre, nella pratica clinica, il non infrequente riscontro di alterazioni diffuse del parenchima epatico, come la steatosi, puo rendere ancora piu difficoltosa una corretta diagnosi [2]. In particolare l’infiltrazione adiposa del fegato,dovuta all’accumulo di trigliceridi sotto forma di vacuoli di differenti dimensioni all’interno degli epatociti, la cui incidenza, secondo alcuni studi autoptici, varia dal 6 all’11%, e responsabile di un’ alterazione diffusa dell’ecogenicita del parenchima epatico che assume un aspetto definito “ brillante”, nel contesto del quale le lesioni epatiche presentano, indipendentemente dalla loro natura, un aspetto prevalentemente ipoecogeno [3, 4]. Inoltre la steatosi puo interessare in maniera focale solo alcune aree del parenchima epatico e, per converso, in un fegato diffusamente steatosico possono esistere le cosiddette “aree di risparmio”, con il risultato di creare pseudolesioni che, specialmente nei pazienti oncologici sottoposti a chemioterapia che spesso sviluppano una steatosi epatica, possono porre problemi di diagnosi differenziale con le metastasi.

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The diagnosis of hepatocellular carcinoma (HCC) can be reached noninvasively on imaging in patients at high risk as discussed in chapter “Hepatocellular carcinoma: Diagnostic Guidelines.” In this chapter, we describe the CT and MR imaging criteria more commonly used in the guidelines for the diagnosis and management of patients with HCC, including arterial phase hyperenhancement, washout, capsule, growth, and hypointensity on hepatobiliary phase MR imaging. The provided definitions are based on the latest version (v2018) of the liver imaging reporting and data system (LI-RADS) document (American College of Radiology 2018, https://www.acr.org/Clinical-Resources/Reporting-and-Data-Systems/LI-RADS).

Background: The purpose of this study was to evaluate High-Resolution CT (HRCT) findings in SARS-CoV-2-related ARDS survivors treated with prolonged low-dose methylprednisolone after hospital discharge. Methods: A total of 44 consecutive patients (M: 32, F: 12, average age: 64), hospitalised in our department from April to September 2020 for SARS-CoV-2-related ARDS, who had a postdischarge CT scan, were enrolled into this retrospective study. We reviewed the electronic medical charts to collect laboratory, clinical, and demographic data. The CT findings were evaluated and classified according to lung segmental distribution. The imaging findings were correlated with spirometry results and included ground glass opacities (GGOs), consolidations, reticulations, bronchiectasis/bronchiolectasis, linear bands, and loss of pulmonary volume. Results: Alterations in the pulmonary parenchyma were observed in 97.7% of patients at HRCT (median time lapse between ARDS diagnosis and HRCT: 2.8 months, range 0.9 to 6.7). The most common findings were linear bands (84%), followed by GGOs (75%), reticulations (34%), bronchiolectasis (32%), consolidations (30%), bronchiectasis (30%) and volume loss (25%). They had a symmetric distribution, and both lower lobes were the most affected areas. Conclusions: A reticular pattern with a posterior distribution was observed 3 months after discharge from severe COVID-19 pneumonia, and this differs from previously described postCOVID-19 fibrotic-like changes. We hypothesized that the systematic use of prolonged low-dose of corticosteroid could be the main reason of this different CT scan appearance.

Introduction Ground-glass nodules may be the expression of benign conditions, pre-invasive lesions or malignancies. The aim of our study was to evaluate the capability of chest digital tomosynthesis (DTS) in detecting pulmonary ground-glass opacities (GGOs). Methods An anthropomorphic chest phantom and synthetic nodules were used to simulate pulmonary ground-glass nodules. The nodules were positioned in 3 different regions (apex, hilum and basal); then the phantom was scanned by multi-detector CT (MDCT) and DTS. For each set (nodule-free phantom, nodule in apical zone, nodule in hilar zone, nodule in basal zone) seven different scans (n = 28) were performed varying the following technical parameters: Cu-filter (0.1–0.3 mm), dose rateo (10–25) and X-ray tube voltage (105–125 kVp). Two radiologists in consensus evaluated the DTS images and provided in agreement a visual score: 1 for unidentifiable nodules, 2 for poorly identifiable nodules, 3 for nodules identifiable with fair certainty, 4 for nodules identifiable with absolute certainty. Results Increasing the dose rateo from 10 to 15, GGOs located in the apex and in the basal zone were better identified (from a score = 2 to a score = 3). GGOs located in the hilar zone were not visible even with a higher dose rate. Intermediate density GGOs had a good visibility score (score = 3) and it did not improve by varying technical parameters. A progressive increase of voltage (from 105 kVp to 125 kVp) did not provide a better nodule visibility. Conclusion DTS with optimized technical parameters can identify GGOs, in particular those with a diameter greater than 10 mm. Implications for practice DTS could have a role in the follow-up of patients with known GGOs identified in lung apex or base region.

Introduction: Despite the constantly growing popularity of radiological imaging in forensic pathology, a systematic review investigating the efficiency and limits of radiological techniques, in comparison to forensic autopsy, was still missing. Aim: The present review aims at providing an overview on the current role of radiology in the forensic investigation of fatal gunshot wounds without any restriction to specific radiological techniques. Material and methods: A systematic literature search on three databases (PubMed, Web of Science, and Science Direct) was performed until December 2017. The Oxford Centre for Evidence Based Medicine (OCEBM) grading system for levels of evidence was applied, in order to weigh published evidence. Results and discussion: Eighty-six papers (1.64% of the records) were included. Despite the quite limited general level of evidence, which contrasts with the abundance of the scientific literature on this topic, several recommendations/statements, coupled to their OCEBM grade, were distilled as for the identification of retained bullets, gunshot wounds detection, diagnosis of entrance and exit wounds, trajectories and internal injury detection and estimation of the firing distance. Conclusions: Imaging radiological technologies represent the present and future of wound ballistics. However,traditional, micro and molecular imaging techniques require further validation through blinded cross-sectional studies with appropriate reference standards (e.g. forensic autopsy).

Urinary tract infection (UTI) is the most common bacterial infection. It accounts for 8.6 million visits in the ambulatory care setting in the United States. Women are at higher risk for UTI, with a self-reported annual incidence of 12%, and by the age of 32, half of them have suffered at least one UTI. Moreover UTI recurrence is high. Luckily acute pyelonephritis is much less common than cystitis, with a peak annual incidence of 25 cases per 10,000 women 15–34 years of age [1]. Infection is initiated when potential pathogens migrate from the bowel lumen to urethra and ascend to the kidneys. Accurate differentiation between uncomplicated UTI (episodes of acute cystitis and pyelonephritis in healthy premenopausal, non-pregnant woman, with no history suggesting abnormalities of urinary tract) and complicated UTI (all the other cases) is mandatory. Imaging helps in disease detection, definition its extent, reveal predisposing conditions and complications. Ultrasound is iexpensive, immediate, painless, widely available and radiation-free, so it should represents he first line imaging modality in the majority of patients. However uncomplicated UTI usually do not require imaging for diagnosis and treatment.

Contrary to upper urinary tract infections (UTI), which affect almost exclusively the kidneys, lower UTI are a more complex entity, affecting several different portions of the genitourinary tract. They consist of a wide spectrum of manifestations, ranging from acute cystitis, which is the most common infection of all the urinary tract counting 0.70 episodes per person-year in young women and 0.07 episodes per person-year in postmenopausal women, to infrequent entities as schistosomiasis or life threatening disease such as Fournier’s gangrene. Enteric flora organisms like Escherichia Coli, Klebsiella Pneumoniae and Enterococcus species are the cause of disease in the vast majority of patients. The role of imaging techniques is strictly related to the severity of presentation varying between either end of possibilities: not required and mandatory. Ultrasound (US) is the technique of choice in most cases, however plain film and computer tomography (CT) may help the diagnostic workup in selected cases demonstrating peculiar findings.

The tumors of the upper urinary tract include tumors developing in the renal pelvis and ureter. Transitional cell carcinomas (TCCs) of the renal pelvis or renal calices are relatively rare tumors of the kidney. Multidetector CT urography is currently considered the most sensitive and comprehensive imaging modality for the evaluation of the entire urinary tract and the detection of TCCs. TCCs may manifest as single or multiple discrete filling defects, filling defects within distended calyces, calyceal obliteration (calyceal amputation), hydronephrosis with renal enlargement caused by tumor obstruction of ureteropelvic junction, or as reduced renal function – excluded kidney – without renal enlargement caused by long-standing tumor obstruction of the ureteropelvic junction and atrophy.

Radical nephrectomy and nephron-sparing surgery represent the surgical procedures applied in renal oncology. The resection of part of the kidney or of the whole kidney parenchyma determines evident change in the retroperitoneal anatomy and in the abdominal and retroperitoneal organ relationship. In this chapter, the normal imaging findings and the fundamental complications after renal surgery detectable by imaging are described. Moreover, the topic of tumoral recurrence and the differential diagnosis between tumoral recurrence and normal postsurgical findings is addressed.

The kidneys are highly vascularized organs. Each kidney receives the highest blood flow per gram of organ weight in the body (1.2 L/min corresponding to 20 % of the cardiac output and a perfusion value of 400 mL/min/100 g). The most employed indicator of the renal function is the glomerular filtration rate (GFR), which can be estimated according to different formulas. The calculation of the GFR is essential for a correct employment of iodinated and gadolinium-based contrast agents. The most widely used equations for estimating GFR are the Cockcroft–Gault and the Modification of Diet in Renal Disease Study Group (MDRD) formulas.

Ultrasound (US) represents the first-line imaging technique in the assessment of the kidney. US image quality has greatly improved in recent years with advances in the transducer and beam-former technology. Gray-scale US, with the addition of harmonic and compound speckle-reduction modes, and color Doppler US may provide a diagnostic clue in most renal abnormalities. US artifacts are extremely important in the US assessment of the kidney because they must be differentiated by true images and may be extremely useful in the renal assessment. Nowadays, contrast-enhanced US with dedicated contrast-specific techniques and microbubble contrast agents further improves the sensitivity of US in depicting renal vasculature.

Renal parenchymal diseases may be characterized by gray-scale and color and power Doppler ultrasound (US). The most typical appearance of renal parenchymal diseases on gray-scale US is a diffuse increase in echogenicity of parenchyma of both kidneys with an increased or a reduced visibility of renal pyramids. Color and power Doppler analysis of intrarenal flows may reveal an increase in the resistive index value (>0.7). Even though gray-scale and Doppler US provide morphological and functional evaluations of renal parenchymal diseases, they do not present high specificity and sensitivity in the characterization of the different renal parenchyma disease.

Urinary tract obstruction refers to the structural or functional changes in the urinary tract that impede the normal flow of urine and is a clinical situation which may be clearly defined by imaging. The different causes of renal obstruction may be easily detected by ultrasound (US) and characterized, thanks to the panoramicity of the new imaging modality such as computed tomography urography (CTU) and magnetic resonance urography (MRU). Pyonephrosis represents the chronic suppurative infection in an obstructed kidney. Grayscale US with tissue harmonic imaging represents the most sensitive imaging technique to detect pyonephrosis. The vesicoureteral reflux is the retrograde flow of urine from the bladder toward the kidney.

Renal biopsy has become a fundamental diagnostic tool both in nephrology, for the diagnostic assessment of many renal diseases, and in oncology, for the characterization of renal masses. A number of different nephrologic diseases can show a similar clinical and laboratory pattern but the histopathological features are different. Biopsy is required as different histological entities are associated with different therapeutic protocols and with different prognoses when considering the renal function. Biopsy of renal masses are becoming more frequent, as this procedure is required in candidates to non surgical treatments, i.e., radiofrequency ablation, and in patients for whom partial nephrectomy may be preferred. The correct patients selection and preparation, the use of modern bioptic devices, the possibility of a real time monitoring of the procedure by means of ultrasound, significantly decreased both patient discomfort and the complication rate of this invasive procedure. Until few years ago renal biopsy was performed in few selected centers, while now it is more widespread but nevertheless it requires a multidisciplinary team where the nephrologist, the radiologist and the pathologist are involved. All these physicians are essential part of the team and are required for the procedure and for the correct diagnostic interpretation.

At the SYnchrotron Radiation for MEdical Physics (SYRMEP) beamline of Elettra Synchrotron Light Laboratory in Trieste (Italy), an extensive research program in bio-medical imaging has been developed since 1997. The core program carried out by the SYRMEP collaboration concerns the use of Synchrotron Radiation (SR) for clinical mammography with the aim of improving the diagnostic performance of the conventional technique. The first protocol with patients, started in 2006 has been completed at the end of 2009 and the data analysis is now in progress. Regarding applications different from clinical imaging, synchrotron X-ray computed microtomography (micro-CT) is the most used technique, both in absorption and phase contrast. A new software tool, Pore3D, has been developed to perform a quantitative morphological analysis on the reconstructed slices and to access textural information of the sample under study.

During the third week of pregnancy, the process of gastrulation results in the formation of trilaminar embryo in humans. This is the beginning of morphogenesis (development of body form). Three germ layers, ectoderm, mesoderm, and endoderm, are present. A specific part of mesoderm, the intermediate mesoderm, gives rise to urogenital system gradually. It starts to develop from nephrogenic cord, which divides in nephrotomes. They give rise to pronephroi and subsequently mesonephroi, the transitory kidneys. Finally, metanephroi appear as the permanent organs, from two different structures: the metanephrogenic blastema (mesenchimal component) that leads to nephrons, and ureteric bud (epithelial component) that gives rise to collecting tubules, calices, renal pelvis, and ureter. Following developmental steps depend on inductive signaling between metanephrogenic blastema and ureteric bud. Many genes, regulating proteins and pathways are involved in the physiological organogenesis. Cell proliferation and apoptosis keep the balance of the growth. Defects in these molecular and morphogenetic mechanisms may cause various congenital abnormalities of the kidney and urinary tract (CAKUT), which represent a family of diseases with a diverse anatomical spectrum.

Renal neoplasm histotypes have been recently reclassified by the World Health Organization. This chapter describes the fundamental imaging features of the most common benign solid renal tumors. The most common benign solid renal tumors are angiomyolipomas and renal oncocytomas. The most typical imaging feature of renal angiomyolipoma is the evidence of macroscopic fat which can be identified by unenhanced CT and by fat-saturation MR sequences. Renal angiomyolipomas with minimal fat component may present the same imaging features of malignant renal masses. The most typical pattern of renal oncocytomas on contrast-enhanced CT consists in a spoke-wheel shape or diffuse enhancement pattern and a sharp, smooth rim. Stellate area of low attenuation may be found in 30–40 % of large oncocytomas.

Chronic renal infections are becoming increasingly rare because of the availability of effective antibiotics and early detection and treatment of both acute renal and urinary tract infections and conditions predisposing a patient to chronic infections. The aim of the present chapter is to illustrate the fundamental imaging features of the different forms of chronic renal infections and the modern imaging of renal tuberculosis with multidetector CT urography. From pathological point of view, the chronic renal infections include two types, interstitial chronic pyelonephritis and granulomatous pyelonephritis, namely, xanthogranulomatous pyelonephritis, malacoplakia, and renal tuberculosis. In this chapter the findings and the role of ultrasonography (US), computed tomography (CT), intravenous excretory urography, and CT urography in the different chronic renal infections are reviewed.

The aims of this chapter are to illustrate the typical imaging findings of the kidney in elderly patients and the typical features of the main renal pathologies in the elderly patient. The kidneys present some important morphologic changes according to the patient’s age, which can be detected first by gray-scale ultrasound (US) and color Doppler US, and second, by all the other imaging modalities. These changes have an impact on patient management, particularly with respect to drug therapy. The landmark is diffuse irregular margins due to nephronangiosclerosis of the intrarenal arteries. The fundamental alterations of renal morphology in elderly patients include size reduction, parenchymal thickness reduction, margin irregularities, and increased cortico-medullary differentiation. The main renal pathologies, including vascular and tumoral diseases, present some peculiar features in the elderly patient.

La molteplicità delle infrastrutture presenti e dei relativi gestori rende la realizzazione della mappa acustica strategica di Milano estremamente complessa. Lo scopo del presente lavoro è quello di mostrare i criteri adottati in fase di strutturazione del modello acustico a partire dalle diverse tipologie di dati acquisiti, preliminarmente raccolti ed elaborati all’interno di un Sistema Informativo Territoriale. In particolare vengono illustrate le soluzioni tecniche intraprese sia nell’organizzazione delle informazioni all’interno del SIT, con particolare riferimento all’elaborazione dei dati di popolazione e dei dati riguardanti i flussi di traffico, sia nell’utilizzo delle stesse nel software di simulazione (caratterizzazione delle diverse sorgenti e dell’ambiente di propagazione e scelta dei parametri di calcolo). Nello sviluppo del progetto ci si è basati sulle linee guida contenute nella “Good Practice Guide for Strategic Noise Mapping” (WG-AEN).

Objective. The purpose of this glossary is to offer an updated guide to the correct terminology for contrast-enhanced sonography. Methods. This report was prepared by a panel of radiologists from the Sonography Section of the Italian Association of Medical Radiology. A leading author prepared a list of terms based on a comprehensive literature survey. The draft was analyzed by 3 experts on the topic of contrast-enhanced sonography. These reviewers reached a consensus and prepared the final version. Results. A list of 137 terms is included. These terms are briefly defined. Their proper application is discussed, with special reference to potential misleading uses. Conclusions. Contrast-enhanced sonography is a relatively new diagnostic tool, now entering clinical practice in several countries. Use of appropriate, universal terminology is mandatory in the scientific setting to allow comparison between different published experiences. Additionally, use of clear, standardized terminology is necessary in the clinical setting to facilitate report understanding by the referring physician. Standardized, nonequivocal nomenclature may also help future diffusion of sonographic contrast media in countries where their application is still not approved.

I mezzi di contrasto ecografici sono costituiti da microbolle (diametro compreso nel range 2–6 µm) contenenti aria oppure gas, caratterizzati da una bassa solubilita nel sangue (perfluorocarburi oppure esafluoruro di zolfo) e da una capsula periferica di varia composizione (galattosio, albumina, oppure fosfolipidi). Le microbolle non presentano una fase tissutale interstiziale, permanendo sempre all’interno dei vasi e comportandosi quindi come dei mezzi di contrasto blood-pool. Le proprieta fisiche delle microbolle sono strettamente correlate al tipo di gas contenuto ed alla composizione della capsula periferica, alla frequenza di insonazione, alla frequenza di ripetizione dell’impulso ultrasonoro ed alla potenza di insonazione acustica [1].

Il rene rappresenta l’organo con la maggiore perfusione (volume di sangue/volume organo) (Fig. 13.1). La quantizzazione della perfusione di un organo parenchimale puo essere eseguita anche mediante eco-contrasto utilizzando tecniche ecografiche contrasto-specifiche e mezzi di contrasto di nuova generazione dotati di prolungata persistenza a livello del circolo ematico periferico. L’assunzione di base e che esista una relazione lineare tra la concentrazione delle microbolle e l’intensita del segnale video. Dopo la somministrazione delle microbolle il rene puo essere insonato ad alta potenza acustica al fine di determinare la rottura delle microbolle e la progressiva riperfusione del letto vascolare renale da parte delle microbolle dei piani adiacenti (Figg. 13.2, 13.3). La cinetica di riempimento del letto vascolare renale puo essere valutata mediante una selettiva quantizzazione del segnale a livello della corticale renale e nella successiva approssimazione dei dati ottenuti [1].

BACKGROUND: We describe different possible enhancement patterns in liver hemangiomas with atypical appearance on baseline ultrasound after microbubble-based contrast agent injection. METHODS: From 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. RESULTS: Centripetal 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. CONCLUSION: Different 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.

injection, which requires that microbubbles have a diameter smaller than 8–10 μm. Free air-filled microbubbles exhibited very limited persistence and efficacy, while aqueous solutions, colloidal suspensions, and emulsions did not meet with the required efficacy and safety profile compatible with US. The physical and chemical properties of the more recently introduced microbubble-based contrast agents are superior to those of the initial agents, and stabilized microbubbles offer both excellent stability and safety profiles, as well as acceptable efficacy. Microbubble-based agents are injectable intravenously and pass through the pulmonary capillary bed after peripheral intravenous injection, since their diameter is below that of red blood cells (Fig. 1.1). Microbubble-based agents are isotonic to human plasma and are eliminated through the respiratory system. With the advent of the new-generation of perfluorocarbon or sulphur hexafluoride-filled microbubbles, the duration of contrast enhancement has increased up to several minutes which provides sufficient time for a complete study of the vascular bed using slow bolus injections or infusions.

E. Quaia, MD Assistant Professor of Radiology, Department of Radiology, Cattinara Hospital, University of Trieste, Strada di Fiume 447, 34149 Trieste, Italy frequently observed in renal cell carcinoma, while a homogeneously bright and wedge-shaped appearance, with evidence of posterior acoustic shadowing, is considered typical for renal angiomyolipoma (Yamashita et al. 1992; Helenon et al. 1997, 2001; Jinzaki et al. 1997). Some typical US patterns have also been described for renal oncocytoma, such as the presence of a central scar that appears as a stellate hypoechoic area and the absence of hemorrhage and necrosis (Helenon et al. 2001). Nevertheless, baseline US has low accuracy in the characterization of renal masses, especially if smaller than 4 cm in diameter, since benign and malignant tumors frequently present a similar appearance (Correas et al. 1999). In fact, approximately 30% of small renal cell carcinomas appear as hyperechoic masses (Forman et al. 1993), while atypical isohypoechoic and slightly hyperechoic angiomyolipomas account for 6% and 29% respectively (Helenon et al. 2001). Furthermore, even benign and malignant renal masses >4 cm may present a similar appearance, and large renal cell carcinomas can resemble large angiomyolipomas on baseline US (large renal cell carcinomas usually display a heterogeneous appearance due to intratumoral necrosis, calcifications, and hemorrhage, while large angiomyolipomas may also appear heterogeneous owing to solid, adipose, and hemorrhagic components). Power Doppler and color Doppler US may reveal different vascular patterns in renal tumors. Jinzaki et al. (1998) identified four vascular patterns relevant to lesion characterization. Intratumoral (pattern 1) or penetrating (pattern 2) vessels were described as typical for benign renal tumors, and in particular for angiomyolipoma, while peripheral (patterns 3) or mixed penetrating and peripheral (pattern 4) vessels were considered typical for renal cell carcinomas, even though they could also be observed in 20% of renal angiomyolipomas. Even though the description of these vascular patterns represents a first endeavor to differentiate the different histotypes of renal tumors using color and power Doppler, this technique does not significantly CONTENTS