Atrial dimension reference values in healthy participants using the biplane/monoplane method for clinical and research use.

AIM: To provide reference values of the dimensions of the left and right atrium (RA) obtained using the biplane and monoplane methods, respectively, on two- and four-chamber views, which represent the standard projections acquired in clinical practice, and correlation with body surface area (BSA), age, and gender. MATERIALS AND METHODS: Healthy volunteers, M:F = 1:1, including five participants per gender and age decile from 20 to 70 years, who underwent cardiovascular magnetic resonance imaging (CMR) were enrolled prospectively. Normal atrial reference values were calculated for male and female subpopulations and stratified by age. Atrial areas and volumes were assessed both as absolute values and indexed to BSA. Differences among genders and correlation with age were assessed. Intra- and interobserver reproducibility were assessed in a subpopulation. RESULTS: Fifty participants (mean age 43.3 ± 14 years, 25 men) were evaluated. Image analysis took <1 minute for each subject (mean time 30 ± 5 seconds). Intra- and interobserver reproducibility were excellent (ICC >0.85 for all datasets). RA areas were significantly higher in males (p=0.0001). The left atrial (LA) surface did not show significant differences among genders. Atrial areas normalised to BSA did not show significant gender differences. Both right and left absolute atrial volumes turned out to be significantly higher in males (p=0.0001 and p=0.0047, respectively), and normalised to BSA remained significantly different only for the RA (p=0.0006). Neither atrial volume nor areas showed significant correlation with age. CONCLUSIONS: The monoplane method is a fast and reproducible technique to assess atrial dimensions. Absolute atrial dimensions show significant variations among genders. Gender-specific reference ranges for atrial dimensions are recommended.

T2-weighted, apparent diffusion coefficient and 18F-FDG PET histogram analysis of rectal cancer after preoperative chemoradiotherapy.

BACKGROUND: The aim of our study was to investigate the correlation among T2-weighted (T2w) images, apparent diffusion coefficient (ADC) maps, 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) images, histogram analysis and the pathological response in locally advanced rectal cancer (LARC) after preoperative chemoradiotherapy (pCRT). METHODS: Patients with LARC were prospectively enrolled between February 2015 and August 2018 and underwent PET/magnetic resonance imaging (MRI). MRI included T2w and diffusion-weighted imaging (DWI)-sequences. ADC maps and PET images were matched to the T2w images. Voxel-based standardized uptake values (SUVs,) ADC and T2w-signal-intensity values were collected from the volumes of interest (VOIs) and mean, skewness and kurtosis were calculated. Spearman's correlation coefficient was applied to evaluate the correlation among the variables and tumor regression grade (TRG), T stage, N stage and fibrosis. RESULTS: Twenty-two patients with biopsy-proven LARC in the low or mid rectum were enrolled [17 males, mean age was 69 years (range 49-85 years)]. Seven patients experienced complete regression (TRG1). A significant positive correlation was found between SUV mean values (ρ = 0.480; p = 0.037) and TRG. No other significant correlations were found. CONCLUSIONS: Histogram analysis of SUV values is a predictor of TRG in LARC.

Radiomics: a new tool to differentiate adrenocortical adenoma from carcinoma.

BACKGROUND: The main challenge in the management of indeterminate incidentally discovered adrenal tumours is to differentiate benign from malignant lesions. In the absence of clear signs of invasion or metastases, imaging techniques do not always precisely define the nature of the mass. The present pilot study aimed to determine whether radiomics may predict malignancy in adrenocortical tumours. METHODS: CT images in unenhanced, arterial, and venous phases from 19 patients who had undergone resection of adrenocortical tumours and a cohort who had undergone surveillance for at least 5 years for incidentalomas were reviewed. A volume of interest was drawn for each lesion using dedicated software, and, for each phase, first-order (histogram) and second-order (grey-level colour matrix and run-length matrix) radiological features were extracted. Data were revised by an unsupervised machine learning approach using the K-means clustering technique. RESULTS: Of operated patients, nine had non-functional adenoma and 10 carcinoma. There were 11 patients in the surveillance group. Two first-order features in unenhanced CT and one in arterial CT, and 14 second-order parameters in unenhanced and venous CT and 10 second-order features in arterial CT, were able to differentiate adrenocortical carcinoma from adenoma (P < 0.050). After excluding two malignant outliers, the unsupervised machine learning approach correctly predicted malignancy in seven of eight adrenocortical carcinomas in all phases. CONCLUSION: Radiomics with CT texture analysis was able to discriminate malignant from benign adrenocortical tumours, even by an unsupervised machine learning approach, in nearly all patients.

Digital tomosynthesis and ground glass nodules: Optimization of acquisition protocol. A phantom study.

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.

The role of CEUS in the characterization of hepatocellular nodules detected during the US surveillance program--current practices in Europe.

The basic pathological feature for the differential diagnosis between hepatocellular carcinoma (HCC) and non-malignant hepatocellular nodules in cirrhotic patients detected during ultrasound (US) is the vascular supply to the nodule. Computed tomography (CT) and magnetic resonance imaging (MRI) are considered reference imaging techniques for depicting hepatocellular nodule vascularity in the noninvasive diagnosis of HCC. Contrast-enhanced US (CEUS) improves the diagnostic performance of unenhanced US in the diagnosis of HCC, giving an overall diagnostic accuracy that is similar to that of CT, even for nodules smaller than 2 cm. An additional diagnostic feature of CEUS relative to CT is the possibility to visualize contrast wash-in to hepatic nodules during the arterial phase and contrast washout during the portal venous and late phases. Sensitivity for the diagnosis of HCC with combined assessment of CEUS and CT is higher than for separate assessments of CEUS and CT due to the reduction of false-negative findings. CEUS represents a competitive imaging method from an economic point of view, and is an effective imaging tool for assessing the therapeutic outcome after surgery, ablation therapy, and transarterial chemoembolization (TACE).

Differential diagnosis between splenic nodules and peritoneal metastases with contrast-enhanced ultrasound based on signal-intensity characteristics during the late phase.

PURPOSE: This study was done to assess the enhancement characteristics of splenic implants and to evaluate whether contrast-enhanced ultrasound (CEUS) after SonoVue injection allows the differential diagnosis with peritoneal metastases. MATERIAL AND METHODS: Thirteen consecutive patients with splenosis and 13 consecutive patients with peritoneal metastases were investigated with CEUS after injection of 2.4 ml of SonoVue. Lesion enhancement was evaluated in real time for 240 s. All examinations were recorded digitally and analysed retrospectively. Frames were selected at different time intervals ranging from 0 to 4 min after injection. Average signal intensity was evaluated by measuring the average grey level in a region of interest encompassing the entire nodule. Results were evaluated using the Mann-Whitney test and interobserver variability using the Bland and Altmann method. RESULTS: Splenic grafts presented with intense enhancement and without significant washout. Metastases presented with variable enhancement and progressive washout. Signal intensity values were significantly higher for splenic grafts, starting from 40 s after microbubble administration. Starting from 90 s after injection, there was no overlapping between enhancement of splenic grafts and peritoneal metastases, and only splenic grafts showed a percent of enhancement higher than 60% of the maximum enhancement. CONCLUSIONS: CEUS after SonoVue injection may be considered a valuable alternative to scintigraphy for characterising peritoneal splenic grafts without radiation.

Radiological-pathological correlation in intratumoural tissue components of solid lung tumours.

The aim of this paper is to describe the intratumoural tissue components of solid lung tumours evidenced by macroscopic and/or microscopic examination of the autopsy or surgical specimen and visible on computed tomography (CT) without and with contrast material administration. Seven intratumoural tissue components can be identified both at CT and at pathology: (1) solid component, (2) haemorrhagic component, (3) coagulation necrosis, (4) liquefaction necrosis, (5) parenchymal consolidation, (6) diffuse peripheral component and (7) fibrotic component. Necrotic and haemorrhagic components are typically observed in malignant lesions, whereas solid and fibrotic components may be seen both in solid lung malignancies and in benign lesions.

Integrated fluorine-18 fluorodeoxyglucose (18F-FDG) PET/CT compared to standard contrast-enhanced CT for characterization and staging of pulmonary tumors eligible for surgical resection.

BACKGROUND: Accurate staging is necessary to determine the appropriate therapy in patients with lung cancer. Few studies have compared integrated fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) and contrast-enhanced CT in the characterization and staging of pulmonary tumors considered eligible for surgical resection. PURPOSE: To compare 18F-FDG PET/CT with standard contrast-enhanced CT for the diagnosis and staging of lung neoplasms eligible for surgical resection. MATERIAL AND METHODS: Seventy-six consecutive patients (56 male, 20 female; mean age+/-SD, 63.4+/-20 years) with 84 pulmonary tumors suspected for malignancy and considered eligible for surgical resection were prospectively enrolled. Seventy-three malignant (65 non-small-cell lung carcinomas, one small-cell lung cancer, two carcinoids, and five metastases) and 11 benign lung tumors (three hamartomas, two sarcoidosis, one amyloidosis, one Wegener granulomatosis, one tuberculosis, and three areas of scarring) were finally diagnosed by histology. Tumor staging was based on the revised American Joint Committee on Cancer. RESULTS: In lesion characterization, the sensitivity and specificity of 18F-FDG PET/CT versus contrast-enhanced CT were 90% vs. 83% and 18% vs. 63% (P<0.05, McNemar test), respectively. In nodal staging, the sensitivity and specificity of 18F-FDG PET/CT versus contrast-enhanced CT were 78% vs. 46% and 80% vs. 93% (P<0.05), respectively. CONCLUSION: In patients with lung neoplasms considered eligible for surgical resection, (18)F-FDG PET/CT versus contrast-enhanced CT revealed higher sensitivity in nodal staging, but lower specificity both in lesion characterization and nodal staging.

The mammography project at the SYRMEP beamline.

A clinical program for X-ray phase contrast (PhC) mammography with synchrotron radiation (SR) has been started in March 2006 at the SYRMEP beamline of Elettra, the SR facility in Trieste, Italy. The original beamline layout has been modified substantially and a clinical facility has been realized. In order to fulfill all security requirements, dedicated systems have been designed and implemented, following redundancy criteria and "fail safe" philosophy. Planar radiographic images are obtained by scanning simultaneously the patient and the detector through the stationary and laminar SR beam. In this first phase of the project a commercial screen-film system has been used as image receptor. Upon approval by the respective authorities, the mammography program is about half way to conclusion. Up to now about 50 patients have been examined. The patients are volunteers recruited by the radiologist after conventional examinations at the hospital resulted in an uncertain diagnosis. As an example one case of PhC SR mammography is shown and compared to conventional digital mammography. Preliminary analysis shows the high diagnostic quality of the PhC SR images that were acquired with equal or less delivered dose compared to the conventional ones.

Contrast-specific ultrasound techniques.

The advent of microbubble contrast agents has determined an important evolution of ultrasound (US) technology due to the introduction of contrast-specific US techniques. This was due to the fact that neither colour or power Doppler are suitable for correct management of the signals produced by microbubble insonation, as they are limited by the heavy presence of artefacts. Microbubbles may be insonated by a characteristic frequency named resonance or fundamental frequency (f (0)) by using a high or low transmit power. If insonated by a high transmit power, microbubbles produce a wideband harmonic signal due to microbubble destruction. If insonated by a low transmit power, microbubbles produce harmonic frequencies (2f, 3f, 4f) due to their nonlinear physical behaviour. Contrast-specific US techniques have recently undergone an important technical development with the introduction of innovative algorithms able to register selectively the harmonic signals produced by microbubbles and to suppress the signal produced by stationary tissues. The different contrast-specific US techniques may be distinguished by their basic principle into pseudo-Doppler, harmonic, phase-modulation, amplitude-modulation and phase-and amplitude-modulation techniques.

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

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.

The feasibility of urethral color ultrasound imaging in the diagnosis of female intrinsic sphincter deficiency: preliminary results.

STUDY DESIGN: Prospective study. OBJECTIVES: To evaluate the feasibility of color ultrasound imaging of the urethra in association with UPP to diagnose intrinsic sphincter deficiency (ISD). SETTING: Italy. METHODS: We studied a group of 13 normal female volunteers (mean age 29 years) during the estrogenic phase and a group of 15 patients (mean age 63.9 years) with ISD. All patients and normal volunteers underwent color ultrasound imaging using a 4-7 MHz convex broad band transducer. Translabial sagittal scans of the urethra were obtained. The color ultrasound parameters were optimized for detection of parenchymal slow flows. A subjective score of the degree of vascularization along the entire urethra was established as follows: (a) minimal or absent (1), (b) poor (2), (c) moderate (3), (d) good (4). Statistical analysis, using the non-parametric Mann-Whitney rank sum test, was carried out to determine differences of ultrasound scores between volunteers and patients. RESULTS: The statistical evaluation showed that the differences between the ultrasound scores in the two groups was statistically significant (P<0.001). CONCLUSION: We affirm that color ultrasound imaging of the urethra seems to be feasible and useful in association with UPP in the diagnosis of ISD even if this echographic investigation needs further observations.

[Current role of color Doppler ultrasound in acute renal failure]. / Stato attuale dell'eco color-Doppler nell-insufficienza renale acuta.

Acute Renal Failure (ARF) is characterized by a rapid decline of the glomerular filtration rate, due to hypotension (prerenal ARF), obstruction of the urinary tract (post-renal ARF) or renal parenchymal disease (renal ARF). The differential diagnosis among different causes of ARF is based on anamnesis, clinical symptoms and laboratory data. Usually ultrasound (US) is the only imaging examination performed in these patients, because it is safe and readily available. In patients with ARF gray scale US is usually performed to rule out obstruction since it is highly sensitive to recognize hydronephrosis. Patients with renal ARF have no specific changes in renal morphology. The size of the kidneys is usually normal or increased, with smooth margins. Detection of small kidneys suggests underlying chronic renal pathology and worse prognosis. Echogenicity and parenchymal thickness are usually normal, but in some cases there are hyperechogenic kidneys, increased parenchymal thickness and increased cortico-medullary differentiation. Evaluation of renal vasculature with pulsed Doppler US is useful in the differential diagnosis between prerenal ARF and acute tubular necrosis (ATN), and in the diagnosis of renal obstruction. Latest generation US apparatus allow color Doppler and power Doppler evaluation of renal vasculature up to the interlobular vessels. A significant, but non specific, reduction in renal perfusion is usually appreciable in the patients with ARF. There are renal pathologic conditions presenting with ARF in which color Doppler US provides more specific morphologic and functional information. In particular, color Doppler US often provides direct or indirect signs which can lead to the right diagnosis in old patients with chronic renal insufficiency complicated with ARF, in patients with acute pyelonephritis, hepatic disease, vasculitis, thrombotic microangiopathies, and in patients with acute thrombosis of the renal artery and vein. Contrast enhanced US is another useful diagnostic tool in patients with ARF which has been recently introduced in clinical practice. Microbubble administration may reduce technical failure in the evaluation of the renal artery. Moreover, perfusion defects due to stenosis or thrombosis of the renal segmentary vessels are better recognized. New diagnostic possibilities of enhanced US include evaluation of both cortical and medullar vessels, and functional evaluation of renal perfusion. Measuring the transit time of the microbubbles is useful for the diagnosis of renal artery stenosis and, in transplanted kidneys, for differential diagnosis between ATN and acute rejection.

Characterization of unifocal liver lesions with pulse inversion harmonic imaging after Levovist injection: preliminary results.

The aim of this study was to evaluate capabilities of pulse inversion harmonic imaging (PIHI) in characterization of unifocal liver lesions. We evaluated with PIHI (HDI5000, ATL, Bothell, Wash.) and spiral CT 46 consecutive patients with a single liver lesion identified by fundamental US [7 hepatocellular carcinomas (HCC), 2 cholangiocarcinomas, 7 focal nodular hyperplasias (FNH), 17 hemangiomas and 13 metastases]. The PIHI was performed before and 30 s, 2 and 4 min after bolus administration of Levovist (2.5 g, 300 mg/ml). Scans were digitally stored and reviewed using a dedicated software. Hepatocellular carcinoma was hyperechoic on 30-s scan, and hypoechoic (n = 5) or isoechoic (n = 2) on 2-min scan. Cholangiocarcinoma had inhomogeneous persistent enhancement. Focal nodular hyperplasia was hyperechoic (n = 5) or isoechoic (n = 2) on 30-s scan, hyperechoic (n = 4), isoechoic (n = 2) or slightly hypoechoic (n = 1) on 2-min scan. Large hemangioma revealed peripheral enhancement on 30-s scan which extended centripetally on 2-min scan. Small hemangioma appeared isoechoic on 2-min scan in all but two cases in which they were hypoechoic on 2-min scans and hyperechoic on 4-min scan. Metastasis was hypoechoic on all scans, 70% with rim enhancement. Similar changes in enhancement pattern have been observed at spiral CT. The 30-s and the 2-min scans revealed a conclusive importance in characterization of HCC, cholangiocarcinoma, and large hemangioma. The 2-min scan often furnished enough information for characterization of small hemangioma and metastasis. The 4-min scan allowed characterization of two hemangiomas which appeared hypoechoic on 2-min scans. In the other cases it did not provide further information. Diagnosis of FNH is usually reached with Colour Doppler US; PIHI should be used when colour Doppler is biased by artefacts or when colour Doppler findings are not characteristic. Our results seem to show that PIHI could be a valuable alternative diagnostic approach to spiral CT for unifocal liver lesion characterization. This hypothesis needs to be confirmed with an increased number of lesions.

Color Doppler sonographic appearance of renal perforating vessels in subjects with normal and impaired renal function.

PURPOSE: The purpose of this study was to assess the prevalence and color Doppler sonographic characteristics of perforating vessels-small arteries and veins connecting the intrarenal vasculature with the capsular plexus-in healthy subjects, in hypertensive patients, and in patients with renal failure due to hypertensive nephroangiosclerosis or ischemic nephropathy. METHODS: Fifteen healthy subjects 24-34 years old, 15 healthy subjects 68-80 years old, 25 hypertensive patients, 25 patients with hypertension and chronic renal failure (15 mild, 10 severe), and 12 patients with hypertension and chronic renal failure and acute renal insufficiency due to ischemic nephropathy underwent color Doppler sonography of both kidneys. RESULTS: The few perforating arteries in healthy and hypertensive patients had various resistance indices and flow toward the capsule. Perforating veins in these patients were much more common than perforating arteries. Perforating arteries with a lower mean resistance index than the mean interlobar resistance index and flow toward the capsule were detected in 76% of kidneys in the patients with mild chronic renal failure and in 20% of those in patients with severe chronic renal failure. Only a few perforating veins were seen in patients with chronic renal failure. In 64% of the kidneys with renal artery stenosis detected in the patients with chronic renal failure complicated by acute renal insufficiency, there were perforating arteries with flow toward the kidney and a mean resistance index higher than the mean interlobar resistance index. CONCLUSIONS: Perforating vessels are recognizable using color Doppler sonography both in healthy subjects and in patients with renal failure. The prevalence and flow characteristics of perforating vessels differ between healthy subjects, patients with mild and with severe chronic renal failure, and patients with chronic renal failure complicated by acute renal insufficiency caused by renal artery stenosis.

Detection of liver metastases with pulse inversion harmonic imaging: preliminary results.

The aim of this study is to evaluate capability of contrast enhanced ultrasonography (US) using pulse inversion harmonic imaging (PIHI) to detect liver metastases in comparison to fundamental B-mode ultrasound and spiral CT. Thirty-six consecutive patients with known malignancies and sonographically proved or suspicious liver metastases have been examined with fundamental B-mode US, with PIHI 2', 4' and 6' after Levovist injection and with four phase spiral-CT. Presence, conspicuity and number of lesions have been evaluated comparing PIHI with fundamental B-mode US and spiral-CT. A strong grey-scale enhancement of the liver parenchyma has been observed 2' and 4' after Levovist injection. The optimum parenchymal enhancement and contrast difference between liver and metastases was observed during the 2' measurements. PIHI revealed more lesions than fundamental B-mode US in 56 % of patients, while in 39 % and in 5 % revealed respectively the same number and fewer lesions. PIHI and spiral-CT were in agreement in 67 % of patients, while in 22 % and 11 % PIHI revealed respectively more and fewer lesions. PIHI accurancy presents restrictions in anterior superficial and in deep liver areas, whereas it may be superior to spiral-CT in studying sub-diaphragmatic liver regions.