Relevance of apparent diffusion coefficient features for a radiomics-based prediction of response to induction chemotherapy in sinonasal cancer.

In this paper, several radiomics-based predictive models of response to induction chemotherapy (IC) in sinonasal cancers (SNCs) are built and tested. Models were built as a combination of radiomic features extracted from three types of MRI images: T1-weighted images, T2-weighted images and apparent diffusion coefficient (ADC) maps. Fifty patients (aged 54 ± 12 years, 41 men) were included in this study. Patients were classified according to their response to IC (25 responders and 25 nonresponders). Not all types of images were acquired for all of the patients: 49 had T1-weighted images, 50 had T2-weighted images and 34 had ADC maps. Only in a subset of 33 patients were all three types of image acquired. Eighty-nine radiomic features were extracted from the MRI images. Dimensionality reduction was performed by using principal component analysis (PCA) and by selecting only the three main components. Different algorithms (trees ensemble, K-nearest neighbors, support vector machine, naïve Bayes) were used to classify the patients as either responders or nonresponders. Several radiomic models (either monomodality or multimodality obtained by a combination of T1-weighted, T2-weighted and ADC images) were developed and the performance was assessed through 100 iterations of train and test split. The area under the curve (AUC) of the models ranged from 0.56 to 0.78. Trees ensemble, support vector machine and naïve Bayes performed similarly, but in all cases ADC-based models performed better. Trees ensemble gave the highest AUC (0.78 for the T1-weighted+T2-weighted+ADC model) and was used for further analyses. For trees ensemble, the models based on ADC features performed better than those models that did not use those features (P < 0.02 for one-tail Hanley test, AUC range 0.68-0.78 vs 0.56-0.69) except the T1-weighted+ADC model (AUC 0.71 vs 0.69, nonsignificant differences). The results suggest the relevance of ADC-based radiomics for prediction of response to IC in SNCs.

A computer-aided diagnosis system for the assessment and characterization of low-to-high suspicion thyroid nodules on ultrasound.

AIM OF THE STUDY: To compare the diagnostic performance of a commercially available computer-aided diagnosis (CAD) system for thyroid ultrasound (US) with that of a non-computer-aided radiologist in the characterization of low-to-high suspicion thyroid nodules. METHODS: This retrospective study included a consecutive series of adult patients referred for US-guided fine-needle aspiration biopsy (FNAB) of a thyroid nodule. All patients were eligible for thyroid nodule FNAB according to the current international guidelines. An interventional radiologist experienced in thyroid imaging acquired the US images subsequently used for post-processing, performed FNAB and provided the US features of each nodule. A radiology resident and an endocrinology resident in consensus performed post-processing using the CAD system to assess the same nodule characteristics. The diagnostic performance and agreement of US features between the CAD system and the radiologist were compared. RESULTS: Sixty-two patients (50 F; age 60 ± 12 years) were enrolled: 77.4% (48/62) of thyroid nodules were benign, 22.6% (14/62) were undetermined to malignant and required follow-up or surgery. Interobserver agreement between the CAD system and the radiologist was substantial for orientation (K = 0.69), fair for composition (K = 0.36), echogenicity (K = 0.36), K-TIRADS (K = 0.29), and slight for margins (K = 0.03). The radiologist demonstrated a significantly higher sensitivity than the CAD system (78.6% vs. 21.4%; P = 0.008), while there was no statistical difference in specificity (66.7% vs. 81.3%; P = 0.065). CONCLUSION: This CAD system is less sensitive than an experienced radiologist and showed slight-to-substantial agreement with the radiologist for the characterization of thyroid nodules. Although it is an innovative tool with good potential, additional efforts are needed to improve its diagnostic performance.

The Extension-Thickness-Damage (ETD) score: a pre-operative hip MR arthrography-based classification to predict type of labrum surgery.

INTRODUCTION: Hip magnetic resonance arthrography (MRA) is the pre-operative imaging modality of choice in patients with labral damage, with several classifications of labral tears having been reported based on MRA findings. Nevertheless, none of the available classification systems allows the surgeon to predict before surgery how a labral tear could be treated. Our purpose was to develop a new MRA-based scoring system of labral tears to predict before surgery the treatment option more suitable for labral tears. MATERIALS AND METHODS: Forty-seven patients (29 males and 18 females; mean age: 35.9 ± 12.4) performed hip MRA for suspicious of femoroacetabular impingement and were afterwards subjected to arthroscopic treatment. Two musculoskeletal radiologists reviewed all pre-operative examinations and provided the Extension-Thickness-Damage score for each patient, based on Extension of tear, Thickness of labrum, and type of Damage. Chondral lesions grading was based on the arthroscopic findings according to Konan classification. For statistical purposes, patients were divided into two groups, depending on the type of treatment: labral repair or debridement. Mann-Whitney U, Chi-square, receiver operator curves, and Cohen kappa statistics were used. RESULTS: 35/47 underwent repair, while 12/47 were debrided. In both groups, the median chondral damage was grade III, with no significant differences (p = 0.439). The median Extension-Thickness-Damage score in the repair group (6) was significantly lower (p < 0.001) than that in the debridement group (8). The highest diagnostic performance (area under the curve) of Extension-Thickness-Damage was 0.819. The inter-observer agreement was substantial in the evaluation of Extension (k = 0.626) and Thickness (k = 0.771), and almost perfect for Damage (k = 0.827). Higher scores of Extension and Thickness were more frequently associated with debridement (p < 0.001; p = 0.0016, respectively), with no significant differences on the basis of Damage parameter (p = 0.284). CONCLUSIONS: The MRA-based Extension-Thickness-Damage score could represent a helpful pre-operative tool, expressing the extent of the damage and its reparability before arthroscopy.

Fluoroscopy- vs ultrasound-guided aspiration techniques in the management of periprosthetic joint infection: which is the best?

BACKGROUND: Fluid samples obtained from an affected joint still play a central role in the diagnosis of periprosthetic joint infection (PJI). It is the only preoperative test able to discover the causative microbiological agent. In the hip, fluid aspiration can be performed through fluoroscopy, ultrasound, or, less commonly, computed tomography. However, there is still a lack of consensus on which method is preferable in terms of efficacy and costbenefit. PURPOSES: We, therefore, asked whether (1) the benefits in terms of sensitivity and specificity and (2) the costs were comparable between fluoroscopy- and ultrasound-guided joint aspirations in a suspicious of hip PJI. METHODS: Between 2013 and 2016, 52 hip aspirations were performed on 49 patients with clinical, radiological, or serological suspicion of PJI, waiting for a revision surgery. The patients were divided in two groups: fluoroscopy- (n = 26) vs ultrasound-guided hip aspiration group (n = 26). These groups were also divided in control and infected patients. The criteria of MusculoSkeletal Infection Society (MSIS) were used, as gold standard, to define PJI. RESULTS: (1) Ultrasound-guided aspiration revealed valid sensitivity (89% vs 60%) and specificity (94% vs 81%) in comparison with fluoroscopic-guided aspiration. (2) The cost analysis was also in favor of ultrasound-guided aspiration (125.30€) than fluoroscopic-guided aspiration (343.58€). CONCLUSIONS: We concluded that ultrasound-guided hip aspiration could represent a valid, safe, and less expensive diagnostic alternative to fluoroscopic-guided aspiration in hip PJI.

Assessment of Stability and Discrimination Capacity of Radiomic Features on Apparent Diffusion Coefficient Images.

The objectives of the study are to develop a new way to assess stability and discrimination capacity of radiomic features without the need of test-retest or multiple delineations and to use information obtained to perform a preliminary feature selection. Apparent diffusion coefficient (ADC) maps were computed from diffusion-weighted magnetic resonance images (DW-MRI) of two groups of patients: 18 with soft tissue sarcomas (STS) and 18 with oropharyngeal cancers (OPC). Sixty-nine radiomic features were computed, using three different histogram discretizations (16, 32, and 64 bins). Geometrical transformations (translations) of increasing entity were applied to the regions of interest (ROIs), and the intra-class correlation coefficient (ICC) was used to compare the features computed on the original and modified ROIs. The distribution of ICC values for minimal and maximal entity translations (ICC10 and ICC100, respectively) was used to adjust thresholds of ICC (ICCmin and ICCmax) used to discriminate between good, unstable (ICC10 < ICCmin), and non-discriminative features (ICC100 > ICCmax). Fifty-four and 59 radiomic features passed the stability-based selection for all the three histogram discretizations for the OPC and STS datasets, respectively. The excluded features were similar across the different histogram discretizations (Jaccard's index 0.77 ± 0.13 and 0.9 ± 0.1 for OPC and STS, respectively) but different between datasets (Jaccard's index 0.19 ± 0.02). The results suggest that the observed radiomic features are mainly stable and discriminative, but the stability depends on the region of the body under observation. The method provides a way to assess stability without the need of test-retest or multiple delineations.

A rare case of unilateral vocal cord paralysis: neurovascular conflict due to an aberrant bronchial artery detected at computed tomography.

We report the case of a 29-year-old patient without medical history presenting with dysphonia associated with left unilateral vocal cord paralysis. The patient underwent a contrast-enhanced computed tomography with an angiographic arterial phase of the head, neck and chest, and the only significant finding was the presence of a large, aberrant right bronchial artery originating directly from the aortic arch, where the recurrent left laryngeal nerve loops. After excluding alternative etiologies, the hypothesis of neurovascular conflict between this vessel and the recurrent left laryngeal nerve was formulated. To the best of our knowledge, this is the first case reported in the literature. Thanks to its high spatial resolution, contrast-enhanced computed tomography is the examination of choice for the study of anatomical variants and should be included in the routine work-up of patients presenting with unilateral vocal cord paralysis.

Refining Tumor Treatment in Sinonasal Cancer Using Delta Radiomics of Multi-Parametric MRI after the First Cycle of Induction Chemotherapy.

BACKGROUND: Response to induction chemotherapy (IC) has been predicted in patients with sinonasal cancer using early delta radiomics obtained from T1- and T2-weighted images and apparent diffusion coefficient (ADC) maps, comparing results with early radiological evaluation by RECIST. METHODS: Fifty patients were included in the study. For each image (at baseline and after the first IC cycle), 536 radiomic features were extracted as follows: semi-supervised principal component analysis components, explaining 97% of the variance, were used together with a support vector machine (SVM) to develop a radiomic signature. One signature was developed for each sequence (T1-, T2-weighted and ADC). A multiagent decision-making algorithm was used to merge multiple signatures into one score. RESULTS: The area under the curve (AUC) for mono-modality signatures was 0.79 (CI: 0.65-0.88), 0.76 (CI: 0.62-0.87) and 0.93 (CI: 0.75-1) using T1-, T2-weighted and ADC images, respectively. The fuse signature improved the AUC when an ADC-based signature was added. Radiological prediction using RECIST criteria reached an accuracy of 0.78. CONCLUSIONS: These results suggest the importance of early delta radiomics and of ADC maps to predict the response to IC in sinonasal cancers.

Baseline MRI-Radiomics Can Predict Overall Survival in Non-Endemic EBV-Related Nasopharyngeal Carcinoma Patients.

Advanced stage nasopharyngeal cancer (NPC) shows highly variable treatment outcomes, suggesting the need for independent prognostic factors. This study aims at developing a magnetic resonance imaging (MRI)-based radiomic signature as a prognostic marker for different clinical endpoints in NPC patients from non-endemic areas. A total 136 patients with advanced NPC and available MRI imaging (T1-weighted and T2-weighted) were selected. For each patient, 2144 radiomic features were extracted from the main tumor and largest lymph node. A multivariate Cox regression model was trained on a subset of features to obtain a radiomic signature for overall survival (OS), which was also applied for the prognosis of other clinical endpoints. Validation was performed using 10-fold cross-validation. The added prognostic value of the radiomic features to clinical features and volume was also evaluated. The radiomics-based signature had good prognostic power for OS and loco-regional recurrence-free survival (LRFS), with C-index of 0.68 and 0.72, respectively. In all the cases, the addition of radiomics to clinical features improved the prognostic performance. Radiomic features can provide independent prognostic information in NPC patients from non-endemic areas.

Unusual skin toxicity associated with sustained disease response induced by nivolumab in a patient with non-small cell lung cancer.

INTRODUCTION: Immunotherapy has shown efficacy in the treatment of different malignancies. Nivolumab, an immune checkpoint inhibitor directed against programmed death-1, has been approved for non-small cell lung cancer (NSCLC) in pretreated patients. Although it is generally well-tolerated, immunotherapy may be complicated by a wide range of immune-mediated adverse events. We describe the case of an uncommon skin toxicity arising as alopecia universalis induced by nivolumab in a patient with NSCLC. CASE DESCRIPTION: A 58-year-old man received nivolumab for metastatic NSCLC after progression to 3 lines of chemotherapy. The treatment was prescribed in June 2016, and induced a rapid and significant disease response. Nivolumab was well-tolerated until May 2017, when partial alopecia at hair and eyelashes appeared. In the next months, alopecia became complete and extended to the whole body surface. The dermatologic picture was compatible with alopecia areata. A topical steroid therapy was attempted, without benefit. The patient refused systemic treatments and is still undergoing nivolumab without new toxicities and with persistent disease response. CONCLUSIONS: This case suggests that alopecia areata may be a rare immune-related adverse event of immune checkpoint agents. Its late onset in our patient is uncommon and unexpected, underlining that the risk of nivolumab-induced toxicity is not limited to the beginning of treatment. Despite its rarity, alopecia areata should be considered in the range of adverse events potentially induced by immune checkpoint inhibitors even in the long term. Potential association between toxicity and efficacy of immunotherapy in NSCLC warrants further investigation.

Intraoperative Strain Elastosonography in Brain Tumor Surgery.

BACKGROUND: Sonoelastography is an ultrasound imaging technique able to assess mechanical properties of tissues. Strain elastography (SE) is a qualitative sonoelastographic modality with a wide range of clinical applications, but its use in brain tumor surgery has been so far very limited. OBJECTIVE: To describe the first large-scale implementation of SE in oncological neurosurgery for lesions discrimination and characterization. METHODS: We analyzed retrospective data from 64 patients aiming at (i) evaluating the stiffness of the lesion and of the surrounding brain, (ii) assessing the correspondence between B-mode and SE, and (iii) performing subgroup analysis for gliomas characterization. RESULTS: (i) In all cases, we visualized the lesion and the surrounding brain with SE, permitting a qualitative stiffness assessment. (ii) In 90% of cases, lesion representations in B-mode and SE were superimposable with identical morphology and margins. In 64% of cases, lesion margins were sharper in SE than in B-mode. (iii) In 76% of cases, glioma margins were sharper in SE than in B-mode. Lesions morphology/dimensions in SE and in B-mode were superimposable in 89%. Low-grade (LGG) and high-grade (HGG) gliomas were significantly different in terms of stiffness and stiffness contrast between tumors and brain, LGG appearing stiffer while HGG softer than brain (all P < ·001). A threshold of 2.5 SE score had 85.7% sensitivity and 94.7% specificity in differentiating LGG from HGG. CONCLUSION: SE allows to understand mechanical properties of the brain and lesions in examination and permits a better discrimination between different tissues compared to B-mode. Additionally, SE can differentiate between LGG and HGG.

Reporting rotator cuff tears on magnetic resonance arthrography using the Snyder's arthroscopic classification.

AIM: To determine diagnostic performance of magnetic resonance arthrography (MRA) in evaluating rotator cuff tears (RCTs) using Snyder's classification for reporting. METHODS: One hundred and twenty-six patients (64 males, 62 females; median age 55 years) underwent shoulder MRA and arthroscopy, which represented our reference standard. Surgical arthroscopic reports were reviewed and the reported Snyder's classification was recorded. MRA examinations were evaluated by two independent radiologists (14 and 5 years' experience) using Snyder's classification system, blinded to arthroscopy. Agreement between arthroscopy and MRA on partial- and full-thickness tears was calculated, first regardless of their extent. Then, analysis took into account also the extent of the tear. Interobserver agreement was also calculated the quadratically-weighted Cohen kappa statistics. RESULTS: On arthroscopy, 71/126 patients (56%) had a full-thickness RCT. The remaining 55/126 patients (44%) had a partial-thickness RCT. Regardless of tear extent, out of 71 patients with arthroscopically-confirmed full-thickness RCTs, 66 (93%) were correctly scored by both readers. All 55 patients with arthroscopic diagnosis of partial-thickness RCT were correctly assigned as having a partial-thickness RCT at MRA by both readers. Interobserver reproducibility analysis showed total agreement between the two readers in distinguishing partial-thickness from full-thickness RCTs, regardless of tear extent (k = 1.000). With regard to tear extent, in patients in whom a complete tear was correctly diagnosed, correct tear extent was detected in 61/66 cases (92%); in the remaining 5/66 cases (8%), tear extent was underestimated. Agreement was k = 0.955. Interobserver agreement was total (k = 1.000). CONCLUSION: MRA shows high diagnostic accuracy and reproducibility in evaluating RCTs using the Snyder's classification for reporting. Snyder's classification may be adopted for routine reporting of MRA.

Repair versus shaving of partial-thickness articular-sided tears of the upper subscapularis tendon. A prospective randomized controlled trial.

PURPOSE: the purpose of this study was to evaluate whether treating partial-thickness articular-sided tears of the upper subscapularis (SSC) tendon with a dedicated suture anchor would result in an internal rotation strength improvement compared with simple shaving of the SSC tendon and footprint. METHODS: twenty-six patients with a limited SSC tendon tear (equal or inferior to the most superior centimeter) in association with a posterosuperior cuff lesion were prospectively randomized to two treatments: repair with a dedicated suture anchor versus shaving of the tendon and footprint. The patients also underwent long head of the biceps (LHB) treatment and posterosuperior cuff tear repair. In each patient the following parameters were measured both preoperatively and at a minimum follow-up of 2.5 years: strength in internal rotation in the bear-hug testing position (using a digital tensiometer), DASH score and Constant scores. MRI assessment of tendon healing was performed at the final follow-up. RESULTS: twenty of the 26 patients (76%) were reviewed after a mean follow-up time of 42 months: 11 patients had undergone SSC tendon repair and nine simple shaving. At final follow-up no significant differences were found between the repaired and shaving group in strength in internal rotation (9.5 ± 3.8 kg versus 10.3±5.4 kg; p=0.7). The DASH score and Constant score also failed to show significant differences between the two groups. Furthermore, no significant difference in SSC tendon healing rate was observed on MRI evaluation. CONCLUSIONS: partial-thickness articular-sided tear of the upper SSC tendon in association with a posterosuperior rotator cuff repair and LHB treatment, when limited to the superior centimeter of the SSC tendon, shows a comparable performance in terms of strength in internal rotation either after simple shaving or a tendon-to-bone repair. LEVEL OF EVIDENCE: Level II, prospective comparative study.

The role of ultrasonography in the assessment of peri-prosthetic hip complications.

PURPOSE: Total hip arthroplasty (THA) is a widespread option for treating hip osteoarthritis. Peri-prosthetic complications after THA represent a common event influencing patient outcome and costs. The purpose of this paper is to report the use of ultrasonography (US) to detect peri-prosthetic complications in symptomatic patients who underwent THA. METHODS: We retrospectively reviewed the records of patients with THA who underwent imaging evaluation between January 2009 and December 2012 at two different institutions. We evaluated the presence/absence of superficial and/or deep peri-prosthetic collections as well as the presence/absence of a cutaneous sinus tract. For patients who underwent both MRI and US, a concordance correlation analysis between US and MR findings was performed. RESULTS: In the reference period, 532 symptomatic patients (mean age ± standard deviation 74 ± 12 years) underwent X-ray and MRI examinations for suspected peri-prosthetic complications. Among them, 111 (20.9 %) underwent also US. Overall, 108 patients underwent both US and MRI. US findings included 67 superficial collections, 48 subcutaneous fistulas, 74 deep peri-prosthetic collections. Twenty-four patients had solid, mass-like peri-prosthetic collections. In 11 patients, no peri-prosthetic complications were seen. MRI findings included 68 superficial collections, 49 subcutaneous fistulas, 79 deep peri-prosthetic collections. Twenty-four patients had solid, mass-like peri-prosthetic collections. In four patients, no peri-prosthetic complications were seen. Concordance analysis between US and MRI findings showed almost perfect agreement (k ≥ 0.89). CONCLUSION: US is an efficient and practical imaging modality to evaluate peri-prosthetic complications in patients with THA, being almost comparable to MRI in detecting and characterizing these complications.

Septic bursitis after ultrasound-guided percutaneous treatment of rotator cuff calcific tendinopathy.

Calcific tendinopathy of the rotator cuff is a common condition. Ultrasound-guided percutaneous aspiration is one of several options to treat this condition. The main advantages of this procedure are short duration, good outcome, and low cost. Furthermore, only minor complications have been reported in the literature, namely, vagal reactions during the procedure and mild postprocedural pain. We report the first case of septic bursitis after ultrasound-guided percutaneous treatment of calcific tendinopathy. Although this is generally considered a very safe procedure, a risk of infection should be taken into account.