Type IV optic nerve and Onodi cell: is there a risk of injury during sphenoid sinus surgery?

Objective: This study aims to determine the prevalence and types of Onodi cells through computed tomography and investigate the relationship between Onodi cell and the surrounding structures, paying particular attention to the risky proximity to the optic nerve canal. Methods: In this study, 430 computed tomography scans of paranasal sinuses were analysed to establish the prevalence and different types of Onodi cells. Furthermore, the relationship between Onodi cell and different patterns of sphenoid sinus pneumatisation and surrounding structures were investigated. Special attention was paid to the relationship between Onodi cell and the optic nerve canal, particularly in cases when the optic nerve canal was bulging by more than 50% into the Onodi cell (Type IV). Results: The Onodi cell was detected in 21.6% of cases, with the most common being Type I (48.5% right, 54.3% left). Type IV bulging of the optic nerve canal into the Onodi cell was observed in 47.1% of cases on the right side, 41.2% on the left side and bilateral in 11.7% of cases. Conclusions: In our series, we observed a high prevalence of Type IV optic nerve bulging into the Onodi cell. For this reason, we suggest that clinicians should always try to identify it in a pre-operative setting with computed tomography to avoid catastrophic consequences during endoscopic sinus surgery approaching the sphenoid area.

A prospective randomized controlled trial comparing target prostate biopsy alone approach vs. target plus standard in naïve patients with positive mpMRI.

BACKGROUND: In the era of mpMRI guided target fusion biopsy (FB), the role of concomitant standard biopsy (SB) in naïve patients still remains under scrutiny. The aim of this study was to compare the detection rate (DR) of clinically significant prostate cancer (csPCa) in biopsy naïve patients with positive mpMRI who underwent FB alone (Arm A) vs FB+SB (Arm B). Secondary objectives were to compare the incidence of complications, the overall PCa DR and the biopsy results with final pathological findings after robotic prostatectomy (RARP). METHODS: This is a single center prospective non-inferiority parallel two arms (1:1) randomized control trial (ISRCTN registry number ISRCTN60263108) which took place at San Luigi Gonzaga University Hospital, Orbassano (Turin, Italy) from 4/2019 to 10/2021. Eligible participants were all adults aged<75 years old, biopsy naïve, with serum PSA<15 ng/mL and positive mpMRI (Pi-Rads V.2>3). FB was performed under ultrasound guidance using the BioJet fusion system; four to six target samples were obtained for each index lesion. SB was performed in accordance with the protocol by Rodríguez-Covarrubias. RARP with total anatomical reconstruction was carried out when indicated. DR of PCa and csPCA (Gleason Score >7) were evaluated. Post-biopsy complications according to Clavien-Dindo were recorded. Concordance between biopsy and RARP pathological findings was evaluated. Fisher's Exact test and Mann-Whitney test were applied; furthermore, Logistic Principal Component Analysis (LogPCA) and Pearson's correlation method, in terms of correlation funnel plots, were performed to explore data in a multivariate way. RESULTS: 201 and 193 patients were enrolled in Arm A and B, respectively. csPCa DR was 60.2% vs. 60.6% in Arm A and B respectively (Δ 0.4%; P=0.93); whilst overall PCa DR was 63.7% vs. 71.0% (Δ 7.3%; P=0.12). However, in a target only setting, the addition of SB homolaterally to the index lesion reaching a non-inferior performance compared to the combined sampling (Δ PCa DR 3%). Although the differences of 7.3% in PCa DR, during RARP were registered similar nerve sparing rate (P=0.89), positive surgical margins (P=0.67) and rate of significant upgrading (P=0.12). LogPCA model showed no distinction between the two cohorts; and Pearson's correlation values turned to be between -0.5 and +0.5. In Arm B, the lesion diameter <10 mm is the only predictive variable of positive SB only for PCa (P=0.04), with an additional value +3% for PCa DR. CONCLUSIONS: In biopsy naïve patients, FB alone is not inferior to FB+SB in detecting csPCa (Δ csPCa DR 0.4%). Δ 7.3% in overall PCa DR was registered between the two Arms, however the addition of further standard samples homolaterally to mp-MRI index lesion improved the overall PCa DR of FB only sampling (Δ PCa DR 3%). The omission of SB did not influence the post-surgical outcomes in terms of NS approach, PSMr and upgrading/downgrading.

Atypical Multiple Sclerosis Lesions or Progressive Multifocal Leukoencephalopathy Lesions: That Is the Question.

Progressive multifocal leukoencephalopathy (PML) is a serious infective disease of the central nervous system that may occur in case of severe immunosuppression or after some treatment for multiple sclerosis (MS) with natalizumab, dimethyl fumarate, and fingolimod. In these case reports, we highlight the importance of differential diagnosis between PML and MS lesions in order to provide rapidly the best treatment option, by discussing the finding of brain (magnetic resonance imaging) MRI suggestive for PML in 2 MS patients, one treated with dimethyl fumarate and the other during natalizumab withdrawal. In both cases, although brain MRI was highly suggestive for PML, the detection of John Cunningham virus-DNA copies in cerebrospinal fluid resulted in negative result. These case reports illustrate the diagnostic process in case of suspected PML, as both patients were diagnosed with suspected PML during a routine brain MRI control, and highlights the importance of providing a strict brain MRI follow-up during dimethyl fumarate treatment, although only a few cases of PML during this therapy have been detected, and during natalizumab suspension phase. In clinical practice, in case of a radiologically suspected case of PML, although not confirmed by the cerebrospinal fluid analysis, the best approach could be to perform a close radiological and clinical monitoring before starting a new MS therapy.

Rhino-Orbital-Cerebral Mucormycosis after Allogeneic Hematopoietic Stem Cell Transplantation and Isavuconazole Therapeutic Drug Monitoring during Intestinal Graft versus Host Disease.

A diagnosis of rhino-orbital-cerebral mucormycosis was made in a 59-year-old man with a secondary acute myeloid leukemia a few days after hematopoietic stem cell transplantation. Prompt treatment with combined antifungal therapy (liposomal amphotericin B and isavuconazole) followed by a procedure of endoscopic sinus surgery resulted in the resolution of the infection. Therapeutic drug monitoring of isavuconazole was performed during the year of treatment showing an increment of plasma concentrations in correspondence with the improvement of intestinal GvHD, thus suggesting that in this or similar conditions TDM for isavuconazole can be of value. A literature review of cases of rhino-orbital-cerebral and rhino-cerebral mucormycosis in allogeneic hematopoietic stem cell transplant recipients was carried out.

An unusual case of complicated rhinosinusitis of the sphenoid sinus involving the cavernous sinus and skull base: Endoscopic sinus surgery and medical therapy.

Isolated sphenoid sinus diseases are generally asymptomatic and relatively uncommon with the potential for serious complications. Patients with this condition should be monitored closely and treated aggressively and either diagnostic or therapeutic intent is often indicated. In the management of a complex, life-threatening condition that involves many different fields of expertise, the otolaryngologist plays a key role in orchestrating different specialists and gaining direct access to the affected area, thus taking the first and essential step towards diagnosis and therapy. Because of the superiority of computed tomography in defining the bony margins and the superior soft tissue resolution of magnetic resonance imaging, these two techniques should be used in a complementary manner in the evaluation of isolated sphenoid sinus disease in addition to mapping the lesion better and identifying intracranial and intraorbital extent. We report an unusual case of isolated rhinosinusitis of the sphenoid sinus involving the cavernous sinus, pterygoid fossae and masticatory space in an immunocompetent patient.

Arytenoid Fixation in Laryngeal Cancer: Radiological Pictures and Clinical Correlations with Respect to Conservative Treatments.

Background: The aim of this retrospective study was to identify different radiological features in intermediate⁻advanced laryngeal cancer (LC) associated with arytenoid fixation, in order to differentiate cases still safely amenable to conservative treatment by partial laryngectomy or chemoradiotherapy. Methods: 29 consecutive patients who underwent open partial horizontal laryngectomies (OPHLs), induction chemotherapy followed by radiotherapy in the case of >50% response (IC + RT) or total laryngectomy were classified as: pattern I (supraglottic LC fixing the arytenoid due to weight effect), pattern II (glottic LC involving the posterior paraglottic space and spreading toward the crico-arytenoid joint and infraglottic extension <10 mm), pattern III (glottic-infraglottic LC involving the crico-arytenoid joint and infraglottic extension >10 mm) and pattern IV (transglottic and infraglottic LC with massive crico-arytenoid unit involvement, reaching the hypopharyngeal submucosa). All glottic cancers treated with surgery were studied by a cross sectional approach. Results: A substantial agreement between the work-up and the pathology results has been obtained in each of the subcategories. Three-year disease-free survivals, local control and freedom from laryngectomy were significantly better in pattern II compared to pattern III⁻IV. Conclusions: LC showing fixed arytenoid due to weight effect or posterior paraglottic space involvement with infraglottic extension <10 mm assessed at the true vocal cord midline are still safely manageable by OPHL or IC + RT.

Case 261: Thymoma Embedded in Thymus with Pleural Implant in Myasthenia Gravis Lambert-Eaton Overlap Syndrome.

History A 29-year-old woman presented with a 6-month history of progressive general fatigue, fluctuating limb weakness, and difficulty climbing stairs. She initially experienced occasional episodes of transient diplopia that developed while reading in the evening. She subsequently started to experience dry eyes and mouth, difficulty chewing, and mild dysphagia that worsened throughout the day. Her medical history included hypothyroidism from Hashimoto thyroiditis and pneumonia with left pleural effusion. She had no smoking history, and her body mass index was normal (23.8 kg/m2). No medication use was reported at admission. Physical examination revealed mild bilateral ptosis, reduced muscle tone and strength that worsened in proximal leg muscles, and decreased deep tendon reflexes. An edrophonium test revealed improvement in muscle strength and eyelid ptosis. Repetitive nerve stimulation revealed low amplitude of compound muscle action potential at rest (0.21 mV), with a marked increase (700%; normal increase, <60%) at high-rate stimulation (50 Hz). Laboratory work-up was unremarkable except for detection of acetylcholine receptor antibodies in the serum (21.30 nmol/L) and P/Q-type voltage-gated calcium channel antibodies (220 pmol/L). Recent MRI of the brain and spine at an outside hospital showed no abnormal findings. At admission, the patient underwent CT of the chest, abdomen, and pelvis followed by thoracic MRI to further evaluate CT findings.

Augmented-reality robot-assisted radical prostatectomy using hyper-accuracy three-dimensional reconstruction (HA3D™) technology: a radiological and pathological study.

OBJECTIVES: To assess the use of hyper-accuracy three-dimensional (HA3D™; MEDICS, Moncalieri, Turin, Italy) reconstruction based on multiparametric magnetic resonance imaging (mpMRI) and superimposed imaging during augmented-reality robot-assisted radical prostatectomy (AR-RARP). PATIENTS AND METHODS: Patients with prostate cancer (clinical stages cT1-3, cN0, cM0) undergoing RARP at our Centre, from June 2017 to April 2018, were enrolled. In all cases, cancer was diagnosed with targeted biopsy at the level of index lesion based on high-resolution (1-mm slices) mpMRI. HA3D reconstruction was created by dedicated software to obtain the 3D virtual model of the prostate and surrounding structures. A specific system was used to overlay virtual data on the endoscopic video displayed by the remote da Vinci® surgical console (Intuitive Surgical Inc., Sunnyvale, CA, USA), and the virtual images were superimposed by the surgeon by the means of the TilePro™ multi-input display technology (Intuitive Surgical Inc.). The AR technology was used in four standardised key steps during RARP. The procedures were modulated differently in cases of prostate cancer without extracapsular extension (ECE) at mpMRI (Group A) or in cases of prostate cancer with ECE (Group B) at mpMRI. In Group A, the virtual image of the prostate was overlaid on the endoscopic view and the intraprostatic lesion was marked on the prostate surface by a metallic clip at the level of the suspicious lesion as identified by the 3D virtual AR image. In Group B, the same step was performed; moreover, a metallic clip was placed at the level of the suspicious ECE on the neurovascular bundles (NVBs) according to the virtual images. Finally, selective biopsies were taken from the NVBs at this level, and then, the entire NVBs were removed for final pathological examination, according to standard clinical indications. For Group A, the pathologist performed a targeted needle biopsy at the level of the metallic clip on the surface of prostate before the sample reduction. For Group B, the presence of tumour was evaluated during the reduction phase, at the level of metallic clip on the prostate surface and at the level of NVBs, sent separately. Finally, an image 3D scanner (Kinect, Microsoft) was used to perform a dimensional comparison between the mpMRI-based 3D virtual reconstruction and the whole-mount specimen. RESULTS: In all, 30 patients were enrolled in the present study, 11 (36.6%) included in Group A and 19 (63.4%) in Group B. In all cases (30/30), final pathology confirmed the location of the index lesion, as cancer was found at the level of the metallic clip. The suspected ECE was confirmed on final pathology in 15/19 cases (79%). The AR-guided selective biopsies at the level of the NVBs confirmed the ECE location, with 11/15 (73.3%) biopsies at the level of NVBs positive for cancer. The mismatch between the 3D virtual reconstruction and the prostate 3D scanning based on the whole-mount specimen was <3 mm in >85% of the gland. CONCLUSION: Our results suggest that a HA3D virtual reconstruction of the prostate based on mpMRI data and real-time superimposed imaging allow performance of an effective AR-RARP. Potentially, this approach translates into better outcomes, as the surgeon can tailor the procedure for each patient.

Case 261.

History A 29-year-old woman presented with a 6-month history of progressive general fatigue, fluctuating limb weakness, and difficulty climbing stairs. She initially experienced occasional episodes of transient diplopia that developed while reading in the evening. She subsequently started to experience dry eyes and mouth, difficulty chewing, and mild dysphagia that worsened throughout the day. Her medical history included hypothyroidism from Hashimoto thyroiditis and pneumonia with left pleural effusion. She had no smoking history, and her body mass index was normal (23.8 kg/m2). No medication use was reported at admission. Physical examination revealed mild bilateral ptosis, reduced muscle tone and strength that worsened in proximal leg muscles, and decreased deep tendon reflexes. An edrophonium test revealed improvement in muscle strength and eyelid ptosis. Repetitive nerve stimulation revealed low amplitude of compound muscle action potential at rest (0.21 mV), with a marked increase (700%; normal increase, <60%) at high-rate stimulation (50 Hz). Laboratory work-up was unremarkable except for detection of acetylcholine receptor antibodies in the serum (21.30 nmol/L) and P/Q-type voltage-gated calcium channel antibodies (220 pmol/L). Recent MRI of the brain and spine at an outside hospital showed no abnormal findings. At admission, the patient underwent CT of the chest, abdomen, and pelvis ( Fig 1 ) followed by thoracic MRI ( Figs 2 , 3 ) to further evaluate CT findings. [Figure: see text][Figure: see text][Figure: see text][Figure: see text][Figure: see text][Figure: see text][Figure: see text][Figure: see text].

Indication to pelvic lymph nodes dissection for prostate cancer: the role of multiparametric magnetic resonance imaging when the risk of lymph nodes invasion according to Briganti updated nomogram is <5.

BACKGROUND: The Briganti updated nomogram (BN) is the most popular predictive model aiming to predict the presence of lymph node invasion (LNI) in patients with prostate cancer (PCa), but it lacks information obtained by preoperative imaging. The primary aim of the study was to evaluate the role of multiparametric prostate magnetic resonance imaging (mp-MRI) in the indication to perform pelvic lymph nodes dissection (PLND) or not in patients with risk of LNI according to BN below 5%. METHODS: Since March 2012 and September 2016, 310 patients who underwent a preoperative mp-MRI for staging purpose and subsequent robot-assisted extended PLND (RAEPLND) were retrospectively evaluated. Mp-MRIs were prospectively analyzed by two experienced radiologists. The imaging parameters analyzed were the presence of extracapsular extension (ECE), seminal vesicles invasion (SVI) and predominant Gleason pattern 4 (pG4). All patients underwent RAEPLND by two experienced surgeons with a standardized technique. A dedicated uropathologist performed all pathological analysis. Univariate analysis and multivariate logistic regression analysis were used in order to identify the predictors of LNI in patients with PCa. RESULTS: In the overall population, 57 (18.4%) patients had histologically proven pN1 disease. 48/250 patients (19.2%) with a risk of LNI ≥5% as calculated by the BN were staged pN1 at final histopathological analysis. 9/60 patients (15.0%) with a risk of LNI <5% as calculated by BN, who underwent RAEPLND anyway according to the findings at mp-MRI, were staged pN1 at final histopathological analysis. At multivariate logistic regression analysis, all the three mp-MRI parameters were significant independent predictors of LNI after RAEPLND. CONCLUSIONS: The role of mp-MRI seemed to be crucial in patients with a risk of LNI <5% as calculated by the BN. The presence of ECE, SVI, or pG4 at mp-MRI was found to be an independent predictor of LNI by itself.

Nonsuppressing normal thymus on chemical-shift MR imaging and anterior mediastinal lymphoma: differentiation with diffusion-weighted MR imaging by using the apparent diffusion coefficient.

OBJECTIVES: To prospectively evaluate usefulness of the apparent diffusion coefficient (ADC) in differentiating anterior mediastinal lymphoma from nonsuppressing normal thymus on chemical-shift MR, and to look at the relationship between patient age and ADC. METHODS: Seventy-three young subjects (25 men, 48 women; age range, 9-29 years), who underwent chemical-shift MR and diffusion-weighted MR were divided into a normal thymus group (group A, 40 subjects), and a lymphoma group (group B, 33 patients). For group A, all subjects had normal thymus with no suppression on opposed-phase chemical-shift MR. Two readers measured the signal intensity index (SII) and ADC. Differences in SII and ADC between groups were tested using t-test. ADC was correlated with age using Pearson correlation coefficient. RESULTS: Mean SII±standard deviation was 2.7±1.8% for group A and 2.2±2.4% for group B, with no significant difference between groups (P=.270). Mean ADC was 2.48±0.38x10-3mm2/s for group A and 1.24±0.23x10-3mm2/s for group B. A significant difference between groups was found (P<.001), with no overlap in range. Lastly, significant correlation was found between age and ADC (r=0.935, P<.001) in group A. CONCLUSIONS: ADC of diffusion-weighted MR is a noninvasive and accurate parameter for differentiating lymphoma from nonsuppressing thymus on chemical-shift MR in young subjects. KEY POINTS: • SII cannot differentiate mediastinal lymphoma from nonsuppressing normal thymus at visual assessment • ADC is useful for distinguishing nonsuppressing normal thymus from mediastinal lymphoma • ADC is more accurate than transverse-diameter and surface-area in this discrimination • ADC of normal thymus is age dependent and increases with increasing age.

Diagnostic Imaging and workup of Malignant Pleural Mesothelioma.

Malignant pleural mesothelioma is the most frequent primary neoplasm of the pleura and its incidence is still increasing.This tumor has a strong association with exposure to occupational or environmental asbestos, often after a long latent period of 30-40 years.Plain chest radiography (CXR) is usually the first-line radiologic examination, but the radiographic findings are nonspecific due to its limited contrast resolution and they need to be complemented by other imaging modalities such as computed tomography (CT), magnetic resonance Imaging (MRI), Positron emission tomography-computed tomography (PET-CT) and ultrasound (US).The aim of this paper is to describe the imaging  features of this malignancy, underlining the peculiarity of CXR, CT, MRI, PET-CT and US and also focusing on diagnostic workup, based on the literature evidence and according to our experience.

Diffusion-weighted quantitative MRI of pleural abnormalities: Intra- and interobserver variability in the apparent diffusion coefficient measurements.

PURPOSE: To assess intra- and interobserver variability in the apparent diffusion coefficient (ADC) measurements of pleural abnormalities. MATERIALS AND METHODS: Diffusion-weighted magnetic resonance imaging was performed in 34 patients to characterize pleural abnormalities, with a 1.5T unit at b values of 0/150/500/800 sec/mm2 . In two sessions held 3 months apart, on perfusion-free ADC maps, two independent readers measured the ADC of pleural abnormalities (two readings for each reader in each case) using different methods of region-of-interest (ROI) positioning. In three methods, freehand ROIs were drawn within tumor boundaries to encompass the entire lesion on one or more axial slices (whole tumor volume [WTV], three slices observer-defined [TSOD], single-slice [SS]), while in two methods one or more ROIs were placed on the more restricted areas (multiple small round ROI [MSR], one small round ROI [OSR]). Measurement variability between readings by each reader (intraobserver repeatability) and between readers in first reading (interobserver repeatability) were assessed using intraclass correlation coefficient (ICC) and coefficient of variation (CoV). Analysis of variance (ANOVA) was performed to compare ADC values between the different methods. The measurement time of each case for all methods in first reading was recorded and compared between methods and readers. RESULTS: All methods demonstrated good (MSR, OSR) and excellent (WTV, TSOD, SS) intra- and interreader agreement, with best and worst repeatability in WTV (lower ICC, 0.977; higher CoV, 3.5%) and OSR (lower ICC, 0.625; higher CoV, 22.8%), respectively. The lower 95% confidence interval of ICC resulted in fair to moderate agreement for OSR (up to 0.379) and in excellent agreement for WTV, TSV, and SS (up to 0.918). ADC values of OSR and MSR were significantly lower compared to other methods (P < 0.001). The OSR and SS required less measurement time (10 and 21/22 sec, respectively) compared to the others (P < 0.0001), while the WTV required the longest measurement time (132/134 sec) (P < 0.0001). CONCLUSION: ADC measurements of pleural abnormalities are repeatable. The SS method has excellent repeatability, similar to WTV, but requires significantly less measurement time. Thus, its use should be preferred in clinical practice. LEVEL OF EVIDENCE: 4 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:769-782.

Apparent diffusion coefficient measurements in diffusion-weighted magnetic resonance imaging of the anterior mediastinum: inter-observer reproducibility of five different methods of region-of-interest positioning.

OBJECTIVES: To investigate inter-reader reproducibility of five different region-of-interest (ROI) protocols for apparent diffusion coefficient (ADC) measurements in the anterior mediastinum. METHODS: In eighty-one subjects, on ADC mapping, two readers measured the ADC using five methods of ROI positioning that encompassed the entire tissue (whole tissue volume [WTV], three slices observer-defined [TSOD], single-slice [SS]) or the more restricted areas (one small round ROI [OSR]), multiple small round ROI [MSR]). Inter-observer variability was assessed with interclass correlation coefficient (ICC), coefficient of variation (CoV), and Bland-Altman analysis. Nonparametric tests were performed to compare the ADC between ROI methods. The measurement time was recorded and compared between ROI methods. RESULTS: All methods showed excellent inter-reader agreement with best and worst reproducibility in WTV and OSR, respectively (ICC, 0.937/0.874; CoV, 7.3 %/16.8 %; limits of agreement, ±0.44/±0.77 × 10-3 mm2/s). ADC values of OSR and MSR were significantly lower compared to the other methods in both readers (p < 0.001). The SS and OSR methods required less measurement time (14 ± 2 s) compared to the others (p < 0.0001), while the WTV method required the longest measurement time (90 ± 56 and 77 ± 49 s for each reader) (p < 0.0001). CONCLUSIONS: All methods demonstrate excellent inter-observer reproducibility with the best agreement in WTV, although it requires the longest measurement time. KEY POINTS: • All ROI protocols show excellent inter-observer reproducibility. • WTV measurements provide the most reproducible ADC values. • ROI size and positioning influence ADC measurements in the anterior mediastinum. • ADC values of OSR and MSR are significantly lower than other methods. • OSR and WTV methods require the shortest and longest measurement time, respectively.

Changes in hepatic perfusion assessed by dynamic contrast enhanced MRI, associated with morphologic evaluation, in patients with liver metastases from colorectal cancer treated with first-line chemotherapy.

INTRODUCTION: Blood perfusion of liver metastases can be non-invasively assessed by dynamic contrast enhanced magnetic resonance imaging (DCE-MRI). The aim of this study was to explore whether the ratio of hepatic arterial to total liver blood flow (Hepatic Perfusion Index-HPI) and the area under the enhancement curve (AUC) of selected liver areas in patients with hepatic metastases from colorectal cancer treated with first-line chemotherapy could predict response and/or be a prognostic variable. PATIENTS AND METHODS: Sequential liver DCE-MRI studies with morphological imaging reconstruction were performed in 43 consecutive patients at baseline and every 3 months during oxaliplatin-based first-line chemotherapy. Data about HPI of the whole liver, and AUC of metastatic and healthy areas were calculated at each time-point and compared both at baseline and sequentially during the treatment. RESULTS: Baseline HPI and AUC values did not discriminate patients responsive to chemotherapy, nor those with better survival outcomes. HPI and AUC values at 3 months decreased significantly more in responders than non-responders. AUCs calculated from areas of the liver with or without neoplastic lesions varied consistently, being increased in progressing patients and decreased in responding patients. DISCUSSION: Our results did not support the hypothesis of a predictive or prognostic role of HPI and AUCs calculated by DCE-MRI in liver metastatic CRC patients, thus the primary endpoint of the study was not reached. However, reduced arterial blood flow in metastatic liver can be obtained by chemotherapy alone, without any anti-angiogenic agent; interestingly, HPI and AUC data suggest a possible relationship between tumor metabolism and entire liver perfusion.

Diffusion-weighted quantitative MRI to diagnose benign conditions from malignancies of the anterior mediastinum: Improvement of diagnostic accuracy by comparing perfusion-free to perfusion-sensitive measurements of the apparent diffusion coefficient.

PURPOSE: To compare perfusion-free to perfusion-sensitive measurements of the apparent diffusion coefficient (ADC) to diagnose benign conditions from malignancies of the anterior mediastinum. MATERIALS AND METHODS: Seventy-six subjects were divided into a "benign conditions" group (A, n = 44) and a "malignancies" group (B, n = 32), based on histological findings. diffusion-weighted magnetic resonance imaging (DW-MRI) was performed at b of 0/150/800 sec/mm(2) . The ADCs were obtained on an ADC map by including (perfusion-sensitive = ADCb0-800 ) and excluding (perfusion-free = ADCb150-800 ) the b = 0 sec/mm(2) . The Mann-Whitney U-test was used to detect differences in ADCb0-800 compared with ADCb150-800 values between all cases, benign conditions, and malignancies. The same test was used to evaluate differences in ADCs between the two groups for each type of measurement (ADCb0-800 and ADCb150-800 ), and receiver-operating characteristic (ROC) curves were obtained to evaluate discrimination abilities with comparison of areas-under-ROC-curves (AUROC). Optimal cutpoints for discrimination between groups were determined by the Youden-Index with computation of accuracy. RESULTS: The median ADCb0-800 was significantly greater compared with ADCb150-800 for all cases (P = 0.0014), benign conditions (P = 0.0412), and malignancies (P = 0.0001). The median percentage of increase was 5.30% for group-A and 22.39% for group-B (P < 0.0001). AUROC of ADC in discriminating between groups was significantly greater for ADCb150-800 (0.932) compared with ADCb0-800 (0.831) (P = 0.001). The optimal cutpoint for distinction between groups was 1.52 × 10(-3) mm(2) /sec (sensitivity = 93.7%, specificity = 88.6%, accuracy = 90.8%) for ADCb150-800 and 1.75 × 10(-3) mm(2) /sec (sensitivity = 75.0%, specificity = 79.5%, accuracy = 77.6%) for ADCb0-800 . CONCLUSION: The use of perfusion-free ADC measurements significantly improves diagnostic accuracy of DW-MRI in differentiating benign conditions from malignancies of the anterior mediastinum. J. Magn. Reson. Imaging 2016;44:758-769.

Diffusion-weighted magnetic resonance imaging of thymoma: ability of the Apparent Diffusion Coefficient in predicting the World Health Organization (WHO) classification and the Masaoka-Koga staging system and its prognostic significance on disease-free survival.

OBJECTIVES: To evaluate the usefulness of diffusion-weighted magnetic resonance for distinguishing thymomas according to WHO and Masaoka-Koga classifications and in predicting disease-free survival (DFS) by using the apparent diffusion coefficient (ADC). METHODS: Forty-one patients were grouped based on WHO (low-risk vs. high-risk) and Masaoka-Koga (early vs. advanced) classifications. For prognosis, seven patients with recurrence at follow-up were grouped separately from healthy subjects. Differences on ADC levels between groups were tested using Student-t testing. Logistic regression models and areas under the ROC curve (AUROC) were estimated. RESULTS: Mean ADC values were different between groups of WHO (low-risk = 1.58 ± 0.20 × 10(-3)mm(2)/sec; high-risk = 1.21 ± 0.23 × 10(-3)mm(2)/sec; p < 0.0001) and Masaoka-Koga (early = 1.43 ± 0.26 × 10(-3)mm(2)/sec; advanced = 1.31 ± 0.31 × 10(-3)mm(2)/sec; p = 0.016) classifications. Mean ADC of type-B3 (1.05 ± 0.17 × 10(-3)mm(2)/sec) was lower than type-B2 (1.32 ± 0.20 × 10(-3)mm(2)/sec; p = 0.023). AUROC in discriminating groups was 0.864 for WHO classification (cut-point = 1.309 × 10(-3)mm(2)/sec; accuracy = 78.1 %) and 0.730 for Masaoka-Koga classification (cut-point = 1.243 × 10(-3)mm(2)/sec; accuracy = 73.2 %). Logistic regression models and two-way ANOVA were significant for WHO classification (odds ratio[OR] = 0.93, p = 0.007; p < 0.001), but not for Masaoka-Koga classification (OR = 0.98, p = 0.31; p = 0.38). ADC levels were significantly associated with DFS recurrence rate being higher for patients with ADC ≤ 1.299 × 10(-3)mm(2)/sec (p = 0.001; AUROC, 0.834; accuracy = 78.0 %). CONCLUSIONS: ADC helps to differentiate high-risk from low-risk thymomas and discriminates the more aggressive type-B3. Primary tumour ADC is a prognostic indicator of recurrence. KEY POINTS: • DW-MRI is useful in characterizing thymomas and in predicting disease-free survival. • ADC can differentiate low-risk from high-risk thymomas based on different histological composition • The cutoff-ADC-value of 1.309 × 10 (-3) mm (2) /sec is proposed as optimal cut-point for this differentiation • The ADC ability in predicting Masaoka-Koga stage is uncertain and needs further validations • ADC has prognostic value on disease-free survival and helps in stratification of risk.

Chemical shift and diffusion-weighted magnetic resonance imaging of the anterior mediastinum in oncology: Current clinical applications in qualitative and quantitative assessment.

Recently, the use of magnetic resonance (MR) in clinical practice for the evaluation of the anterior mediastinum has considerably increased due to technological improvements and standardization of thoracic protocols. Currently, MR imaging is increasingly seen as a useful problem-solving modality, especially in equivocal cases at computed tomography, with the advantage of a higher contrast resolution and no radiation exposure. Chemical shift and diffusion-weighted MR are helpful in tissue characterization and present advantages over conventional MR imaging, first in providing quantitative data, without the need for the administration of contrast medium. By detecting microscopic fat in tissue, chemical shift imaging is useful for differentiating normal thymus and rebound hyperplasia from cancer tissue at diagnosis and after chemotherapy in oncologic patients, and for distinguishing lymphoid hyperplasia from thymoma in autoimmune diseases such as myasthenia gravis. Diffusion-weighted MR reflects diffusivity of water molecules within tissue and is increasingly used as a cancer biomarker, even in the thorax, for the detection and characterization of tumors, for their differentiation from benign conditions, and for monitoring treatment response. In this review, based on the current literature, technical considerations about image acquisition and data analysis of chemical shift and diffusion-weighted MR are discussed along with clinical applications in the field of benign and malignant disease of the anterior mediastinum.

The challenging diagnosis of pancreatic masses: not all tumors are cancers.

In the elderly patients, where biopsy-induced complications could outweigh the benefit, the identification of pancreatic masses is generally referred to as a synonymous of pancreatic cancer and patients are dismissed with no further options than palliative and supportive care. Notwithstanding, not all pancreatic tumors are cancers and therefore alternative diagnoses need to be investigated, especially when patients are unfit for invasive diagnostic procedures. Here, we report a case of an aged patient that was admitted to an internal medicine division for a previously diagnosed pancreatic cancer. The reassessment of the diagnosis has allowed identifying the pancreatic mass as a manifestation of focal pancreatitis in the context of an IgG4-related disease. Accordingly, patient was treated with steroids with rapid clinical improvement. This clinical case suggests that autoimmune diseases should always be considered in the differential diagnosis of pancreatic masses of the elderly.

Diffusion-weighted MRI in a case of nonsuppressing rebound thymic hyperplasia on chemical-shift MRI.

Rebound thymic hyperplasia (RTH) generally retains the quadrilateral or triangular shape typical of the normal thymus. Nevertheless, RTH may rarely appear as a focal mass, a condition that mimics tumors if reveals soft tissue attenuation at computed tomography (CT). In such cases, chemical-shift magnetic resonance imaging (MRI) can demonstrate microscopic fat within tissue, that would be indistinct at CT, by showing signal suppression on opposed-phase images relative to in-phase images, although two cases of nonsuppressing thymus have been described in early adulthood, both of them with minimally fat amount at histology, but none with RTH. Albeit diffusion-weighted MRI could be helpful in cases of nonsuppressing RTH at chemical-shift MRI, considering its capability in differentiating benign from malignant lesions, currently, no data are available on its use in such cases. Hereby, we report a case of atypical RTH at CT with no signal suppression on chemical-shift MRI, arose after corticosteroid treatment for mixed cryoglobulinemia in a 60-year-old woman. Diffusion-weighted MRI demonstrated unrestricted diffusion, as generally seen for benign tissue with no cellular atypia, and thus was helpful to differentiate RTH from malignant mediastinal tumors, especially from B cell lymphoma related to type II cryoglobulinemia.