Alessandro Guarise

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.

Characterization of cystic tumors of the pancreas: CT accuracy.

PURPOSE The purpose of this work was to evaluate the capabilities of CT to accurately characterize cystic tumors of the pancreas. METHOD Two observers retrospectively evaluated the CT exams of 100 cystic masses of the pancreas, with pathological confirmation. The two observers, blinded about clinical information and the final diagnosis, tried to categorize the lesions according to well established morphologic features. Statistical analysis was performed to measure the agreement between each radiologist and the consensus diagnosis and to evaluate the usefulness of certain CT findings in differentiating one type of cystic pancreatic neoplasm from another. RESULTS Serous cystadenoma was better diagnosed by CT [Youden misclassification index (Ymi) = 0.72] than mucinous cystic tumor (Ymi = 0.44) and solid pseudopapillary tumor (cystic variant) (Ymi = 0.47). CONCLUSION As patients with previous history of pancreatitis were excluded from the study, CT findings allowed correct characterization of only 60% of cystic pancreatic masses. Among the remaining 40%, 15-20% of the wrong diagnoses could not be corrected by means of CT, given the patterns shown by the tumors. In 20-25% of the cases, a nonspecific diagnosis of cystic mass was made.

Serous cystadenoma of the pancreas : Report of 30 cases with emphasis on the imaging findings

PURPOSE Our goal was to evaluate retrospectively 30 cases of serous cystadenoma (SCA) to determine its main imaging features as well as to discuss the differential diagnosis problems versus the other cystic lesions of the pancreas. METHOD Thirty SCAs were analyzed; they were all benign lesions, proven at surgery. Twenty-three tumors were evaluated with US, 26 with CT, and 5 with MRI. RESULTS Three different morphostructural patterns were identified: microlacunar (n = 19), mixed (n = 6), and macrolacunar (n = 5). The diagnosis of SCA, possible in either the microlacunar or the mixed patterns, was achieved in 74% of cases with US (17/23) and in 61.5% with CT (16/26). Among the 19 patients evaluated with both modalities, the joint information allowed a correct diagnosis in 16 cases (84%). The five macrolacunar tumors were undistinguishable from other cystic masses of the pancreas. CONCLUSION The diagnosis of SCA can be considered certain in the microlacunar, likely in the mixed, and not possible in the macrolacunar type.

Nonfunctioning endocrine tumors of the pancreas: Possibilities of spiral CT characterization

Abstract. The aim of this study was to assess the ability of spiral CT to adequately characterize the nonfunctioning endocrine tumors (NFETs) of the pancreas, distinguishing this lesion from the other pancreatic tumors. The spiral CT examinations of 21 cases of histologically proven NFETs, along with those of 29 cases of other pancreatic tumors and tumor-like lesions, were retrospectively reviewed in a blinded fashion by two radiologists, in order to correctly classify the lesions, highlighting the typical signs reported in the literature. Discordant cases were further analyzed in the presence of a third radiologist. The final diagnosis was acquired by means of a majority or overall consensus. The histopathologic examination was considered the gold standard. The sensitivity, specificity, and positive and negative predictive values of CT were calculated. After the consensus evaluation, the correct diagnosis was reached in 72% of cases, with 10% of nonspecific diagnoses of solid pancreatic tumor and 18% of wrong diagnoses. The sensitivity and specificity of spiral CT in identifying NFETs were 66.6 and 82.7%, respectively. The positive and negative predictive values were 73.7 and 77.4%, respectively. In up to 70% of cases the NFET demonstrates a typical aspect of a mass hyperdense in the arterial contrastographic phase eventually associated with hyperdense hepatic metastases in more than half of the patients. This finding does allow the diagnosis of NFET but without certainty indeed, since other tumors can show a similar densitometric behavior and among them particularly the ductal adenocarcinoma. On the other hand, both the solid, hypovascularized NFETs, and the cystic form, cannot be differentiated from the other solid and cystic tumors of the pancreas.

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.

Intraductal papillary mucinous tumors of the pancreas: spectrum of CT and MR findings with pathologic correlation.

Abstract. The reports of intraductal papillary mucinous tumors (IPMT) of the pancreas are increasingly more frequent in the literature. The diagnosis by means of cross-sectional imaging of these tumors is not easy, especially in the early stages, when they can mimic an inflammatory disease of the pancreas. Prompt identification of the disease is nevertheless extremely important, especially in the case of tumors originating from the collateral branches, since its recognition can modify the management of the patient, in some cases obviating recourse to surgery.

Contrast agents for hepatic MRI

Abstract 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.

Pelvic endometriosis: US and MRI features

Endometriosis represents a common and important clinical problem of women of childbearing age. It is a disabling disorder manifesting with pain and infertility. The exact pathogenesis of the disease remains unclear, despite the different theories that have been formulated. The literature on endometriosis is extensive, but often in regard to classic endometrioma. It is surprising that, to the best of our knowledge, the many radiologic features of extraovarian endometriosis have not been well documented thus far. Although ultrasound (US) remains the imaging modality of choice in the radiologic evaluation of female patients with pelvic pain, the role of magnetic resonance imaging (MRI) in the evaluation of abdominal pain is expanding. In the young patient, MRI may be performed if a gynecologic disorder is not suspected at first, especially if US findings are equivocal or the abnormality extends beyond the field of view of the sonographic probe. Moreover, MRI is useful whenever further characterization of pelvic disorder is required. In fact, many causes of pelvic disorders and of endometriosis in particular demonstrate characteristic MRI findings. For these reasons, in this work we describe the protean US and MRI appearances of endometrial foci as encountered in daily experience.

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

Abstract 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.

High-resolution CT of nontuberculous mycobacteria pulmonary infection in immunocompetent, non-HIV-positive patients

PurposeThe objective of this study was to demonstrate that nontuberculous mycobacteria (NTM) pulmonary infections are not so infrequent and that the diagnosis may be suggested on the basis of the high-resolution computed tomography (HRCT) pattern alone.Materials and methodsWe retrospectively reviewed HRCT scans of 29 patients (9 men, 18 women; mean age 63 years, range 38–88 years) with positive culture from bronchial wash. Mycobacterium avium complex (MAC) was present in all (with the exception of one in whom the NTM was indistinct). In six patients, MAC was associated with M. chelonae, M. kansasii, M. fortuitum or M. xenopi. In one of these patients, MAC was associated with both M. fortuitum and M. chelonae. All patients had had nonspecific symptoms of pulmonary infection for a time ranging from 6 months to 12 years. Previous tuberculous infection was present in five patients (18.5%). Eleven patients had other pulmonary diseases (40.8%), and 12 had associated systemic diseases (44.4%).ResultsHRCT findings were apical fibrotic scarring (n=8; 29.6%), consolidations (n=16; 59.2%), single/multiple nodules >1 cm (n=8, multiple; 29.6%), cavitations (n=7; 25.9%), ground glass appearance (n=3; 11.1%), reticular/reticulonodular pattern (n=6; 22.2%), bronchiectasis (n=25; 92.5%), centrilobular nodules (tree in bud) (n=24; 88.8%), air trapping (n=8; 29.6%), lymphadenopathy >1 cm, also with calcification (n=13, 3 with calcification; 48.1%) and pleural effusion (n=2; 7.4%). In 3/7 patients with nodules >1 cm and with cavitations, the “feeding bronchus sign” (a patent bronchus running into a cavitation) was present. Lesions were in the upper lobes in 23 (85.1%), middle lobe/lingula in 25 (92.5%) and lower lobes in 18 (66.6%) patients. The findings were diffuse in 13 (48.1%) cases and patchy in 17 (62.9%).ConclusionsHRCT findings are essential for the diagnosis of NTM pulmonary infection. The presence of bronchiectasis, cavitary nodules with feeding bronchus sign and tree-in-bud nodules in the middle lobe and lingula are suggestive of NTM infection, thus assisting the physician in the diagnostic workup of these patients.RiassuntoObiettivoScopo di questo lavoro è di dimostrare come l’infezione da micobatteri non tubercolari (NTM) non sia così infrequente e come sia possibile suggerirla al clinico e al microbiologo, a volte solo sulla base del pattern in tomografia computerizzata ad alta risoluzione (HRCT).Materiali e metodiSono stati rivalutati retrospettivamente gli esami HRCT di 27 pazienti (9 maschi e 18 femmine; età media 63 anni, range 38–88 anni) con diagnosi microbiologica (esame colturale del broncoaspirato) di infezione da NTM. In tutti i pazienti era presente il M. avium complex (MAC), tranne in uno in cui il NTM è rimasto indefinito; in 6 pazienti vi era associazione di MAC con M. chelone, M. kansasii, M. fortuitum o M. xenopi. In uno di questi vi era l’associazione di MAC sia con M. fortuitum che M. chelone. In tutti erano presenti sintomi aspecifici di patologia polmonare (dispnea, tosse, a volte con escreato, febbre o febbricola, calo ponderale e astenia) con durata variabile da 6 mesi a 12 anni. Pregressa infezione tubercolare era presente in 5 pazienti (18,5%), 11 pazienti (40,8%) avevano fattori di rischio rappresentati da pre-esistenti malattie polmonari e 12 (44,4%) da malattie sistemiche, anche in associazione tra loro.RisultatiI segni HRCT riscontrati sono stati esiti cicatriziali agli apici (8, 29,6%), addensamenti parenchimali (16, 59,2%), nodulo solitario/multipli con diametro >1 cm (8 multipli, 29,6%), cavitazioni dei noduli (7/8, 87,5%), vetro smerigliato (3, 11,1%), quadro reticolare/reticolo-nodulare (6, 22,2%), bronchiettasie (25, 92,5%), noduli centrolobulari (albero con gemme) (24, 88,8%), air trapping (8, 29,6%), linfonodi con diametro >1 cm ed eventuali calcificazioni (13, 3 con calcificazioni, 48,1%), versamento pleurico (2, 7,4%). In 3 dei 7 pazienti con noduli maggiori di 1 cm e con cavitazione è stato individuato il feedings bronchus sign, cioè la presenza di un bronco dilatato con pareti ispessite, a contatto con il nodulo escavato. Le lesioni interessavano i lobi superiori in 23 (85,1%), i lobo medio/lingula in 25 (92,5%) e i lobi inferiori in 18 (66,6%) pazienti. La diffusione delle lesioni è stata uniforme in 13 (48,1%) casi e a carta geografica in 17 (62,9%).ConclusioniSi può affermare che l’HRCT è metodica fondamentale nel riconoscimento e nella diagnosi di infezione polmonare da NTM. La presenza di bronchiettasie, di noduli escavati con il feedings bronchus sign e di noduli centrolobulari ad albero con gemme, con distribuzione prevalente nel lobo medio e nella lingula devono suggerire la possibilità di infezione da NMT, e orientare così il clinico verso la ricerca del germe responsabile.