Are iatrogenic renal artery pseudoaneurysms more challenging to embolize when associated with an arteriovenous fistula?

BACKGROUND: Iatrogenic injuries of the renal artery include pseudoaneurysms (PSA) and pseudoaneurysms with arteriovenous fistula (PSA + AVF). They can cause hematuria, anemization and flank pain. Endovascular treatment is recommended due to its effectiveness. OBJECTIVE: To assess the potential difference between the embolization of iatrogenic renal PSA and iatrogenic renal PSA + AVF, in terms of technical and clinical success rate, procedure complexity and impact on the renal function. METHODS: We retrospectively reviewed 30 embolization procedures of iatrogenic renal PSA and renal PSA + AVF in 27 patients in two centers between December 2006 and February 2017, comparing technical and clinical success rate, total procedural time, creatinine before and after the procedure and parenchymal ischemic area after the procedure. All patients underwent CT before embolization procedure and different embolization materials were used. RESULTS: We identified 15 iatrogenic renal PSA and 15 iatrogenic renal PSA + AVF (causes: 23 nephron-sparing surgery, 2 nephrostomies, 1 lithotripsy, 1 ureteroscopic pyelolithotomy, 1 renal biopsy). Microcoils were used in 21 cases, microcoils and Spongostan in 3 cases, microcoils and controlled-release microcoils in 4 cases and controlled-release microcoils in 1 case. No significant statistical differences were found in the comparison of technical and clinical success rate, total procedural time, creatinine and parenchymal ischemic area after the procedure. CONCLUSIONS: Transarterial embolization can be considered as the first-line treatment for renal artery iatrogenic lesions, considering its effectiveness. No statistical significant differences were found in the comparison of the embolization procedures of iatrogenic renal PSA and PSA + AVF.

Different pixel pitch and maximum luminance of medical grade displays may result in different evaluations of digital radiography images.

AIM: To evaluate the effects of display pixel pitch and maximum luminance on intra- and inter-observer reproducibility and observer performance when evaluating chest lesions and bone fractures. MATERIALS AND METHODS: This was a multi-institutional study for a retrospective interpretation of selected digital radiography images. Overall, 82 images were selected by senior radiologists, including 50 cases of chest lesions and 32 cases of bone fractures. These images were displayed at two pixel pitches (0.212 and 0.165 mm size pixels) and two maximum luminance values (250 and 500 cd/m2) and reviewed twice by senior and junior radiologists. All the observers had to indicate the likelihood of the presence of the lesions and to rate the relative confidence of their assessment. Cohen Kappa statistic was computed to estimate the reproducibility in correctly identifying lesions; for multi-reader-multi-case (MRMC) analysis, weighted Jackknife Alternative Free-response Receiver Operating Characteristic (wJAFROC) statistical tools was applied. RESULTS: The intra-radiologist and inter-observer reproducibility values were the highest for the 0.165 mm size pixel at 500 cd/m2 display, for both chest lesions and bone fractures evaluations. As regards chest lesions, observer performances were significantly greater with 0.165 mm size pixel display at 500 cd/m2 than with lower maximum luminance and/or larger pixel pitch displays. Concerning bone fractures, the performance obtained with 0.212 mm size pixel display at 250 cd/m2 was statistically lower than that obtained with 0.165 mm sixe pixel display at 500 cd/m2. CONCLUSION: Our results indicate that an increased maximum luminance level and a decreased pixel pitch of medical-grade display improve the accuracy of detecting both chest lesions and bone fractures.

Cryotherapy of Renal Lesions: Enhancement on Contrast-Enhanced Sonography on Postoperative Day 1 Does Not Imply Viable Tissue Persistence.

OBJECTIVES: To investigate whether persistent enhancement detected on contrast-enhanced sonography at postoperative day 1 (early contrast-enhanced sonography) after cryoablation of renal tumors implies the presence of residual viable tumor tissue, defined as residual enhancing tissue on reference imaging (computed tomography or magnetic resonance imaging) performed 6 months after the procedure. METHODS: Seventy-four patients with percutaneous cryoablation of renal tumors had early contrast-enhanced sonography from November 2011 to August 2015. Two independent readers evaluated early contrast-enhanced sonographic findings and contrast-enhanced sonographic investigations performed 1 month after cryoablation of lesions that displayed enhancement on early contrast-enhanced sonography. They scored intralesional enhancement in 4 groups: no enhancement, few intralesional vessels, focal enhancing areas, and diffuse enhancement. Inter-reader agreement in evaluating lesion vascularity on early contrast-enhanced sonography was assessed with weighted κ statistics. Computed tomography or magnetic resonance imaging performed 6 months after the treatment was the reference procedure for assessing the absence or presence of residual disease. RESULTS: Inter-reader agreement in assessing intratumoral vascularization on early contrast-enhanced sonography was very good (κ = 0.90). Enhancement was absent for both readers in 33 of 74 cases; only a few intralesional vessels were visible in 21; whereas diffuse or focal enhancement was present in 13. In the remaining 7 patients, there were differences. Four lesions with focal enhancement on early contrast-enhanced sonography and 1 that was considered avascular had residual tumors on reference imaging. Ablation was successful in the remaining 69 of 74 patients (93%). CONCLUSIONS: After cryoablation, intratumoral enhancement on early contrast-enhanced sonography does not imply tumor cell viability.

Comparison of Contrast-Enhanced Ultrasound Scan (CEUS) and MRI in the follow-up of cryoablation for small renal tumors. Experience on 25 cases.

INTRODUCTION: Percutaneous ablation in the kidney is now performed as a standard therapeutic nephron-sparing option in patients who are poor candidates for resection. Its increasing use has been largely prompted by the rising incidental detection of renal cell carcinomas with cross-sectional imaging and the need to preserve renal function in patients with comorbid conditions, multiple renal cell carcinomas, and/or heritable renal cancer syndromes. To date, clinical studies indicate that cryoablation is an effective therapy with acceptable short- to intermediate-term outcomes and with a low risk in the appropriate setting. 
This article focuses on the efficiency of contrast enhanced ultrasound scan (CEUS) as compared to contrast enhanced magnetic resonance imaging (MRI) during the follow-up after cryoablation of small renal tumors.
 MATERIAL & METHODS: In our Department, percutaneous or laparoscopic assisted cryoablation is offered in the treatment of small renal masses. 
Between January 2009 and January 2013, 25 patients (pts) were treated with laparoscopic assisted cryoablation or percutaneous cryoablation for renal tumors <3.5 cm in pts unfit for surgery. All pts had severe comorbidities (ASA score 3). Transperitoneal laparoscopic approach was performed in 11 pts, extraperitoneal approach in 3 pts, percutaneous technique was performed in 11 patients. "Tru-cut biopsy" of the renal mass was always performed before cryoablation.
 The SeedNet system (Galil Medical, Arden Hills, MN) was used in 12/25 pts; the Precise system (Galil Medical, Arden Hills, MN) was used in 13/25 pts. In all cases, IceRod needles were used. Real-time ultrasound guidance was used to localize the tumour and to monitor the progression of "iceball". A double "freeze-thaw cycle" was used. 
All pts had MRI and CEUS before cryoablation and the follow-up consisted in CEUS/MRI every 3 months during the first year and every 6 months thereafter.
 RESULTS: The mean age of the 25 pts was 67.7 years (range 56-79); 5 pts were females and 20 were males. The mean tumor size was 2.8 cm (range 1.5-3.5). No patient required conversion to open procedure. 19 tumors were located at the lower pole, 4 were interpolar and 2 tumors were located at the upper pole. There were no intraoperative complications. The mean hospital stay was 4 days (range 1-7). Two pts required a blood transfusion; there was no statistically significant difference between preoperative and postoperative serum creatinine levels. The biopsy showed RCC in all cases. In 24/25 patients both CEUS and MRI showed no enhancement. In 1/25 pts, during the follow-up, CEUS and MRI showed a well visible recurrence at the perfusion study. It was histologically confirmed. The final results of CEUS and MRI were concordant in all pts. CONCLUSIONS: CEUS is effective during the follow-up of renal tumor cryoablation. It could be an alternative technique to standard CT and MRI, with some advantages: low cost, short time consuming procedure, no radiation exposure, reduced amount of contrast agent (1-2 mL) and rare adverse reactions.

Italian registry of cardiac magnetic resonance.

OBJECTIVES: Forty sites were involved in this multicenter and multivendor registry, which sought to evaluate indications, spectrum of protocols, impact on clinical decision making and safety profile of cardiac magnetic resonance (CMR). MATERIALS AND METHODS: Data were prospectively collected on a 6-month period and included 3376 patients (47.2 ± 19 years; range 1-92 years). Recruited centers were asked to complete a preliminary general report followed by a single form/patient. Referral physicians were not required to exhibit any specific certificate of competency in CMR imaging. RESULTS: Exams were performed with 1.5T scanners in 96% of cases followed by 3T (3%) and 1T (1%) magnets and contrast was administered in 84% of cases. The majority of cases were performed for the workup of inflammatory heart disease/cardiomyopathies representing overall 55.7% of exams followed by the assessment of myocardial viability and acute infarction (respectively 6.9% and 5.9% of patients). In 49% of cases the final diagnosis provided was considered relevant and with impact on patient's clinical/therapeutic management. Safety evaluation revealed 30 (0.88%) clinical events, most of which due to patient's preexisting conditions. Radiological reporting was recorded in 73% of exams. CONCLUSIONS: CMR is performed in a large number of centers in Italy with relevant impact on clinical decision making and high safety profile.

Carotid artery stenting in difficult aortic arch anatomy with or without a new dedicated guiding catheter: preliminary experience.

OBJECTIVES: To evaluate carotid artery stenting (CAS) procedures with or without a new dedicated guiding catheter in anatomically challenging aortic arches in our experience. METHODS: We retrospectively reviewed 172 procedures of CAS performed from December 2006 to October 2011 in 159 consecutive patients (100 men, mean age 78 years): 15 patients had type III aortic arch, 13 had a bovine aortic arch, 6 had an acute angle at the origin of the left common carotid artery from the aortic arch, 2 had type III aortic arch with bovine aortic arch, and 1 had a bicarotid trunk with an aberrant right subclavian artery. In this group of difficult anatomy (37 cases), CAS was performed with (13 cases) or without (24 cases) a new dedicated guiding catheter. RESULTS: Mean time of fluoroscopy (16 min vs. 18 min, P < 0.01), mean total procedural time (68 min vs. 83 min, P < 0.001), technical failure (0/13 vs. 3/24 cases, P = 0.01), clinical failure (0/13 vs. 4/21 cases, P = 0.02) and local complications (0/13 vs. 2/24 cases, P < 0.0001) were significantly lesser in the dedicated guiding catheter group. CONCLUSIONS: The new dedicated guiding catheter may be more effective and less risky for CAS in anatomically challenging aortic arches. KEY POINTS: • Complex anatomy of the aortic arch is not rare • Endovascular carotid artery stenting (CAS) is more difficult when the anatomy is complex • A new dedicated guiding catheter may help CAS when the arch anatomy is complex • The new dedicated guiding catheter may be less risky in complex arches.

Solid hypervascular liver lesions: accurate identification of true benign lesions on enhanced dynamic and hepatobiliary phase magnetic resonance imaging after gadobenate dimeglumine administration.

PURPOSE: To evaluate hepatobiliary phase magnetic resonance imaging with gadobenate dimeglumine for differentiation of benign hypervascular liver lesions from malignant or high-risk lesions. METHODS AND MATERIALS: Retrospective assessment was performed of 550 patients with 910 hypervascular lesions (302 focal nodular hyperplasia [FNH], 82 nodular regenerative hyperplasia [NRH], 59 hepatic adenoma or liver adenomatosis [HA/LA], 329 hepatocellular carcinomas [HCC], 12 fibrolamellar-HCC [FL-HCC], 21 peripheral cholangiocarcinomas [PCC], 105 metastases). Imaging was performed before and during the arterial, portal-venous, equilibrium, and hepatobiliary phases after gadobenate dimeglumine administration (0.05 mmol/kg). Histologic confirmation was available for ≥1 lesion per patient, except for patients with suspected FNH (diagnosis based on characteristic enhancement/follow-up). Lesion differentiation (benign/malignant) on the basis of contrast washout and lesion enhancement (hypo-/iso-/hyperintensity) was assessed (sensitivity, specificity, accuracy, PPV, and NPV) relative to histology or final diagnosis. RESULTS: On portal-venous or equilibrium phase images, washout was not seen for 208 of 526 (39.5%) malignant (HCC, FL-HCC, PCC, metastases) and high-risk (HA/LA) lesions. Conversely, only 5 of 384 (1.3%) true benign lesions (FNH/NRH) showed washout. Taking washout as indicating malignancy, the sensitivity, specificity, and accuracy for malignant lesion identification during these phases was 61.8%, 98.7%, and 77.4%. On hepatobiliary phase images, 289 of 302 FNH, 82 of 82 NRH, 1 of 59 HA or LA, 62 of 341 HCC or FL-HCC, and 2 of 105 metastases were hyperintense or isointense. Taking iso- or hyperintensity as an indication for lesion benignity, the sensitivity, specificity, accuracy, PPV, and NPV for benign lesion identification was 96.6%, 87.6%, 91.4%, 85.1%, and 97.3%, respectively. CONCLUSIONS: Hepatobiliary phase imaging with gadobenate dimeglumine is accurate for distinguishing benign lesions from malignant or high-risk lesions. Biopsy should be considered for hypointense lesions on hepatobiliary phase images after gadobenate dimeglumine.

Percutaneous retrieval of a radiolucent foreign body from an EVAR device by combining different image modalities.

Percutaneous extraction techniques are an established method for removing endovascular foreign bodies. Generally, the foreign body to be removed is radiopaque (i.e., catheter and guidewire fragments, vena cava filters, embolization coils, endovascular stents). We propose an application of these techniques to remove a radiolucent foreign body (i.e., pigtail cover) by means of a combination of different imaging techniques (fluoroscopy, digital subtraction angiography, ultrasound, and computed axial tomography).

Evaluation of serial changes of pancreatic branch duct intraductal papillary mucinous neoplasms by follow-up with magnetic resonance imaging.

The purpose of this study was to clarify the biological behaviour of branch duct type intraductal papillary mucinous neoplasm (IPMN) by evaluating serial changes at magnetic resonance cholangiopancreatography (MRCP). Fifty-two patients with a diagnosis of branch duct IPMN based on either endoscopic retrograde cholangiopancreatography (ERCP) (9/52) and/or MRCP examination (43/52), were followed up over a mean period of 31.2 months (range 12-108). All imaging data were retrospectively reviewed by two radiologists in order to evaluate serial changes in the maximum diameter of the cystic lesion, in the presence of main pancreatic duct dilatation (MPD), and filling defects within the lesion. Statistical analysis was performed using the Fisher exact probability test. Serial MRCP proved growth in seven cases. In two cases the size decreased; in the remaining 43 there was no change in size. Lesions greater than 3 cm at presentation and the presence of MPD dilatation or filling defects at imaging were most likely to grow. Only 2/37 cystic lesions less than 3 cm in diameter grew in size over the period of observation. No cystic lesion showed changes in morphology and structure. Branch duct IPMNs smaller than 3 cm, without associated filling defects, tend to be stable, making 'watch and wait' management possible.

Contrast agents for hepatic MRI.

Liver specific contrast media (LSCM) can be subdivided according to different modalities of hepatic distribution: exclusive distribution to the hepatocellular compartment can be obtained using CM which accumulate within the hepatocytes after slow infusion; other CM demonstrate combined perfusion and hepatocyte-selective properties, with an initial distribution to the vascular-interstitial compartment (in an analogous manner to that of the conventional extracellular CM), thereafter, a fraction of the injected dose is taken up into the hepatocytes causing an increase in the signal intensity of the hepatic tissue. The use of the superparamagnetic effect of iron oxide particles is based on distribution in the reticuloendothelial system (RES), usually well represented in the normal parenchyma as well as in benign hepatocellular lesions, and absent in most malignant lesions. It is necessary to have an in-depth knowledge of either the biological and histological characteristics of focal liver lesions (FLL) or the enhancement mechanism of LSCM to gain significant accuracy in the differential diagnosis of FLL. Dynamic contrast-enhanced MRI is an important tool in the identification and characterization of FLL. With LSCM it is possible to differentiate benign from malignant lesions and hepatocellular lesions from non hepatocellular lesions with high accuracy. To understand the contrast behaviour after injection of LSCM it is necessary to correlate the contrast enhancement with both the biological and histological findings of FLL.

Branch-duct intraductal papillary mucinous neoplasms of the pancreas: to operate or not to operate?

BACKGROUND: Branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) of the pancreas are reported to be less aggressive than the main-duct type. Hence, less aggressive treatment has been proposed for the former. AIM: To evaluate the effectiveness of a follow-up protocol for BD-IPMNs. DESIGN: Prospective study. SETTING: An academic tertiary referral centre. PATIENTS: From 2000 to 2003, 109 patients with BD-IPMNs underwent trans-abdominal ultrasound and magnetic resonance cholangiopancreatography with secretin. Patients who presented malignancy-related parameters (size >3.5 cm, nodules, thick walls, carbohydrate antigen 19.9 level >25 U/l, recent-onset or worsened diabetes) and/or complained of symptoms were submitted to surgery (arm A). All asymptomatic patients without suspicion of malignancy were followed up according to a 6-month clinical-radiological protocol (arm B). MAIN OUTCOME MEASURES: The effectiveness of conservative management of BD-IPMNs. RESULTS: 20 (18.3%) patients underwent surgery (arm A); pathological diagnosis of BD-IPMNs was always confirmed. 89 (81.7%) patients were followed up for a median of 32 months (arm B); of these, 57 (64%) patients had multifocal disease. After a mean follow-up of 18.2 months, 5 (5.6%) patients showed an increase in lesion size and underwent surgery. The pathological diagnosis was branch-duct adenoma in three patients and borderline adenoma in two. CONCLUSIONS: Surgery is indicated in <20% of cases of BD-IPMNs, and, in the absence of malignancy-related parameters, careful non-operative management seems to be safe and effective in asymptomatic patients. Although observation for a longer time is needed to confirm these results, our findings support the guidelines recently recommended by the International Association of Pancreatology.

Cystic tumors of the pancreas.

Cystic tumors of the pancreas are less frequent than solid lesions and are often detected incidentally, as many of these lesions are small and asymptomatic. However, they may be associated with pancreatitis or have malignant potential. With advancements in diagnostic imaging, cystic lesions of the pancreas are being detected with increasing frequency. Many lesions can cause a pancreatic cyst, most being non-neoplastic while approximately 10% are cystic tumors, ranging from benign to highly malignant tumors. With increasing experience it is becoming clear that the prevalence of pseudocyst among cystic lesions of the pancreas is lower than usually presumed. A presumptive diagnosis of pseudocyst based on imaging appearance alone can cause a diagnostic error, and neoplastic cysts of the pancreas are particularly susceptible to this misdiagnosis, which can result in inappropriate treatment. Cystic tumors of the pancreas are formed by serous or mucinous structures showing all stages of cellular differentiation. According to the WHO classification, they can be subdivided on the basis of their histological type and biological behavior into benign tumors, borderline tumors, and malignant tumors. Cystic pancreatic tumors can be subdivided into peripheral (serous cystadenomas, mucinous cystic tumors, solid and papillary epithelial neoplasms, cystic islet cell tumors), which do not communicate with the main pancreatic duct, and ductal tumors (mucinous tumor), according to their site of origin. On the basis of imaging criteria alone, it can be very difficult to differentiate non-tumoral cystic lesions from neoplastic ones. The management of these patients is complex, and it is important to correlate imaging findings with knowledge of the patient's symptoms and of the natural history and predictors of malignancy in pancreatic cysts.

Duodenal duplication cyst causing severe pancreatitis: imaging findings and pathological correlation.

We here report a case of a 18-year-old man with a history of recurrent abdominal pain and a previous episode of severe acute pancreatitis. Abdominal ultrasonography, contrast enhanced multislice computer tomography, endoscopic retrograde cholangiopancreatography, endoscopic ultrasonography and magnetic resonance imaging demonstrated a cystic mass lesion. Only on delayed phase magnetic resonance images after Gadolinium-BOPTA injection, it was possible to demonstrate the lesionos relationship with the biliary tree, differentiating the lesion from intraluminal duodenal diverticulum, and to achieve the diagnosis of duodenal duplication cyst, a recognized rare cause of acute pancreatitis. The diagnosis was confirmed by histology.

Diagnostic accuracy of MRCP in choledocholithiasis.

PURPOSE: To evaluate the accuracy of MRCP in diagnosing choledocholithiasis considering Endoscopic Retrograde Cholangiopancreatography (ERCP) as the gold standard. To compare the results achieved during the first two years of use (1999-2000) of Magnetic Resonance Cholangiopancreatography (MRCP) in patients with suspected choledocholithiasis with those achieved during the following two years (2001-2002) in order to establish the repeatability and objectivity of MRCP results. MATERIALS AND METHODS: One hundred and seventy consecutive patients underwent MRCP followed by ERCP within 72 h. In 22/170 (13%) patients ERCP was unsuccessful for different reasons. MRCP was performed using a 1.5 T magnet with both multi-slice HASTE sequences and thick-slice projection technique. Choledocholithiasis was diagnosed in the presence of signal void images in the dependent portion of the duct surrounded by hyperintense bile and detected at least in two projections. The MRCP results, read independently from the ERCP results, were compared in two different and subsequent periods. RESULTS: ERCP confirmed choledocholithiasis in 87 patients. In these cases the results of MRCP were the following: 78 true positives, 53 true negatives, 7 false positives, and 9 false negatives. The sensitivity, specificity and accuracy were 90%, 88% and 89% respectively. After the exclusion of stones with diameters smaller than 6 mm, the sensitivity, specificity and accuracy were 100%, 99% and 99%, respectively. MRCP accuracy was related to the size of the stones. There was no significant statistical difference between the results obtained in the first two-year period and those obtained in the second period. CONCLUSIONS: MRCP is sufficiently accurate to replace ERCP in patients with suspected choledocholithiasis. The results are related to the size of stones. The use of well-defined radiological signs allows good diagnostic accuracy independent of the learning curve.

The interrupted rim sign in acute cholecystitis: a method to identify the gangrenous form with MRI.

We present the imaging findings on MR of a patient with acute gangrenous cholecystitis that demonstrated patchy enhancement of the gallbladder mucosa on gadolinium-enhanced fat-saturated T1-weighted gradient echo images. This interrupted rim of mucosal enhancement correlated with patchy areas of necrosis and inflammation of the gallbladder mucosa on the histopathological examination.