Diffusion-weighted MRI in the evaluation of renal lesions:preliminary results

The purpose of this study was to evaluate the capability and the reliability of diffusion-weighted MRI in the evaluation of normal kidney and different renal lesions. 39 patients (10 normal volunteers and 29 patients with known renal lesions) underwent MRI of the kidneys by using a 1.5 T superconducting magnet. Axial fat suppressed turbo spin echo (TSE) T2 and coronal fast field echo (FFE) T1 or TSE T1 weighted images were acquired for each patient. Diffusion-weighted (DW) images were obtained in the axial plane during breath-hold (17 s) with a spin-echo echo planar imaging (SE EPI) single shot sequence (repetition time (TR)52883 ms, echo time (TE)561 ms, flip angle590°), with b value of 500 s mm22. 16 slices were produced with slice thickness of 7 mm and interslice gap of 1 mm. An apparent diffusion coefficient (ADC) map was obtained at each slice position. The ADC was measured in an approximately 1 cm region of interest (ROI) within the normal renal parenchyma, the detected renal lesions and the collecting system if dilated. ADC values in normal renal parenchyma ranged from 1.7261023 mm2 s21 to 2.6561023 mm2 s21, while ADC values in simple cysts (n513) were higher (2.8761023 mm2 s21 to 4.0061023 mm2 s21). In hydronephrotic kidneys (n56) the ADC values of renal pelvis ranged from 3.3961023 mm2 s21 to 4.0061023 mm2 s21. In cases of pyonephrosis (n53) ADC values of the renal pelvis were found to be lower than those of renal pelvis of hydronephrotic kidneys (0.7761023 mm2 s21 to 1.0761023 mm2 s21). Solid benign and malignant renal tumours (n57) showed ADC values ranging between 1.2861023 mm2 s21 and 1.8361023 mm2 s21. In conclusion diffusion-weighted MR imaging of the kidney seems to be a reliable way to differentiate normal renal parenchyma and different renal diseases. Clinical experience with this method is still preliminary and further studies are required

Efficacy of radiofrequency ablation in autonomous functioning thyroid nodules. A systematic review and meta-analysis

Whether thermal ablation is effective to treat toxic thyroid nodules (TTN) is still unknown. Aim of this review was to achieve more robust evidence on the efficacy of radiofrequency ablation (RFA) in treating TTN in terms of TSH normalization, thyroid scintiscan, and volume reduction rate (VRR). A comprehensive literature search of PubMed/Medline and Scopus was performed in November 2018 to retrieve published studies. Original papers reporting TTN treated by RFA and later followed-up were eligible. Excluded were: articles not within this field, articles with unclear data, overlapping series, case/series reports. Discordances were solved in a final collegial meeting. Information was collected concerning population features, treatment procedure, follow-up, cases with TSH normalization, cases with scintiscan normalization, VRR of nodules. Pooled prevalence of patients with TSH or scintiscan normalization, and pooled VRR over time were calculated. For statistical analysis, the random-effects model was used. Eight articles published between 2008 and 2018 were included. The overall number of AFTN treated by RFA was 205. Five studies used a single session of treatment. The time of follow-up ranged from six to 24 months. The pooled rate of patients with TSH normalization was 57%. The pooled rate of patients with scintigraphically proven optimal response was 60%. The pooled VRR at 1 year was 79%. Baseline nodules volume was associated with the rate of TSH normalization. In conclusion, a moderate efficacy of RFA in treating TTN was found, and this can represent a solid starting point in this field

Minimally-invasive treatments for benign thyroid nodules: recommendations for information to patients and referring physicians by the Italian Minimally-Invasive Treatments of the Thyroid group

Purpose: In this paper, the members of the Italian Working Group on Minimally-Invasive Treatments of the Thyroid (MITT group) aim to summarize the most relevant information that could be of help to referring physicians and that should be provided to patients when considering the use of MITT for the treatment of benign thyroid nodules. Methods: An interdisciplinary board of physicians with specific expertise in the management of thyroid nodules was appointed by the Italian MITT Group. A systematic literature search was performed, and an evidence-based approach was used, including also the knowledge and the practical experience of the panelists to develop the paper. Results: The paper provides a list of questions that are frequently asked by patients to operators performing MITT, each with a brief and detailed answer and more relevant literature references to be consulted. Conclusions: This paper summarizes the most relevant information to be provided to patients and general practitioners/referring physicians about the use of MITT for the treatment of benign thyroid nodules

Contrast medium-induced nephropathy. Aspects on incidence, consequences, risk factors and prevention

Contrast media-induced nephropathy (CIN) is a well-known complication of radiological examinations employing iodine contrast media (I-CM). The rapid development and frequent use of coronary interventions and multi-channel detector computed tomography with concomitant administration of relatively large doses of I-CM has contributed to an increasing number of CIN cases during the last few years. Reduced renal function, especially when caused by diabetic nephropathy or renal arteriosclerosis, in combination with dehydration, congestive heart failure, hypotension, and administration of nephrotoxic drugs are risk factors for the development of CIN. When CM-based examinations cannot be replaced by other techniques in patients at risk of CIN, focus should be directed towards analysis of number and type of risk factors, adequate estimation of GFR, institution of proper preventive measures including hydration and post-procedural observation combined with surveillance of serum creatinine for 1-3 days. For the radiologist, there are several steps to consider in order to minimise the risk for CIN: use of “low-“ or “iso-osmolar” I-CM and dosing the I-CM in relation to GFR and body weight being the most important as well as utilizing radiographic techniques to keep the I-CM dose in gram iodine as low as possible below the numerical value of estimated GFR. There is as yet no pharmacological prevention that has been proven to be effective

Valutazione semplificata del momento flettente cinematico considerando il comportamento non lineare del palo e del terreno

Nel presente contributo viene studiato il problema del momento flettente cinematico indotto alla testa di un palo in calcestruzzo armato (impedito di ruotare in testa) per effetto del passaggio delle onde sismiche nel caso di elevati livelli di deformazione di taglio nel terreno, tenendo conto anche del comportamento non lineare del palo. A tal fine viene preso in esame un palo immerso in un deposito di argilla NC, alla base del quale vengono applicati sette accelerogrammi caratterizzati da diverso contenuto in frequenza. Tali input sismici sono stati scalati a tre livelli crescenti di accelerazione di picco su roccia. In tal modo è possibile studiare il momento cinematico al crescere dei livelli deformativi nel terreno, specialmente, nel caso in cui questi ultimi superano i valori oltre i quali il comportamento del terreno non può più essere approssimato con un modello lineare equivalente. Viene quindi illustrata una procedura analitica semplificata per valutare il momento cinematico alla testa del palo, i cui risultati verranno confrontati con quelli ottenuti da analisi numeriche più sofisticate

Kinematic pile-head bending under large earthquake-induced shear strains

The problem of kinematic bending moments imposed at the head of a single pile during the passage of seismic waves is explored under large shear strains in the surrounding soil. To this end, non-linear soil response at free-field conditions is derived numerically by a freely-available 1D code and then utilized to calibrate the constitutive law of soil introduced in a rigorous 3D Finite-Difference (FD) model of the soil-pile system employed to obtain pile's head bending moments. The pile is considered embedded to a normally-consolidated clay and seven earthquake records with different amplitude and frequency content are imposed as input motions at the base of the soil layer, thus allowing the investigation of pile kinematic bending with increasing levels of shear strains in the soil, exceeding the limit of equivalent-linear soil behavior. The performance of a simple analytical expression for predicting the kinematic bending moment at the pile-head is compared to the rigorous FD solution. It is concluded that this simple solution is still applicable, with slight modifications, for high shear strains related to non-linear soil behavior close to shear failure, provided that the proper mobilized soil properties from 1D soil response analysis are introduced

Kinematic pile-head bending under large earthquake-induced shear strains

The problem of kinematic bending moments imposed at the head of a single pile during the passage of seismic waves is explored under large shear strains in the surrounding soil. To this end, non-linear soil response at free-field conditions is derived numerically by a freely-available 1D code and then utilized to calibrate the constitutive law of soil introduced in a rigorous 3D Finite-Difference (FD) model of the soil-pile system employed to obtain pile's head bending moments. The pile is considered embedded to a normally-consolidated clay and seven earthquake records with different amplitude and frequency content are imposed as input motions at the base of the soil layer, thus allowing the investigation of pile kinematic bending with increasing levels of shear strains in the soil, exceeding the limit of equivalent-linear soil behavior. The performance of a simple analytical expression for predicting the kinematic bending moment at the pile-head is compared to the rigorous FD solution. It is concluded that this simple solution is still applicable, with slight modifications, for high shear strains related to non-linear soil behavior close to shear failure, provided that the proper mobilized soil properties from 1D soil response analysis are introduced

Caratterizzazione e co-smaltimento in discarica di rifiuti pretrattati

Lo studio sperimentale ha avuto come obiettivo l’analisi della evoluzione delle caratteristiche biochimiche e meccaniche di rifiuti urbani parzialmente biostabilizzati cosmaltiti con scorie da incenerimento in ambiente anaerobico. A tale scopo sono stati realizzati due impianti in scala pilota, per la simulazione di discariche monorifiuto e di cosmaltimento; in particolare nel primo impianto è stata depositata unicamente Frazione Organica di Rifiuti Solidi Urbani (FORSU) biostabilizzata aerobicamente per una durata di 15 giorni, mentre nel secondo impianto una miscela, in rapporto 30/70 in peso, di scorie da incenerimento di rifiuti urbani e FORSU, avente le medesime caratteristiche e provenienza di quella utilizzata nel primo reattore. I risultati ottenuti hanno mostrato che attraverso il cosmaltimento delle due diverse tipologie di rifiuto, nelle condizioni operative sopra descritte, è possibile conseguire una riduzione del carico inquinante del percolato ed una più rapida stabilizzazione meccanica dell’ammasso di rifiuti

Ultrasonography plus direct radiography of the abdomen in the diagnosis of renal colic: still a valid approach?

PURPOSE: The authors analyze whether the imaging approach consisting of ultrasonography and plain film in patients with renal colic is still of value when urography is replaced by unenhanced helical CT (UHCT) in unsolved cases. MATERIAL AND METHODS: Eight hundred and three consecutive patients were investigated with US following hydration and KUB, 164 of whom (20.4%) subsequently underwent UHCT (42 with the aim of mapping the excretory pathway and 122 (15.2%) because US and KUB were not considered as fully diagnostic). RESULTS: The 42 patients with detectable ureteral stone (plus possible hydronephrosis) on KUB + US and subsequently examined by UHCT to plan interventional treatment all had a positive UHCT examination. In 62 patients the diagnosis following KUB + US was uncertain (possible stone or possible hydronephrosis) and UHCT depicted the stone and/or the hydronephrosis in 34. In 60 patients the combination of KUB + US was negative but colic recurred and UHCT was positive in 17 patients. DISCUSSION: The comparison of the present results with a previous study in which KUB and US were followed by IVU in unsolved cases underscores the value of the first approach with KUB and US. The need for further diagnostic investigations when KUB + US are either not conclusive or negative and colic recurs is also confirmed. On the basis of our present data and in agreement with the literature IVU can be safely replaced by UHCT. CONCLUSIONS: It is authors' opinion that in settings where KUB, US and UHCT are available throughout the 24 hr the approach consisting of KUB plus US and UHCT in unsolved cases can be preferred in view of its on lower cost and above all lower X-ray dose to patients as compared to UHCT as the sole investigation