Maria Twomey

The impact of body composition parameters on ipilimumab toxicity and survival in patients with metastatic melanoma.

Background:Body composition is an important predictor of drug toxicity and outcome. Ipilimumab (Ipi), a monoclonal antibody used to treat metastatic melanoma, has specific toxicities. No validated biomarkers that predict Ipi toxicity and efficacy exist. Also, the impact of Ipi on body composition has not been established.Methods:Patients with metastatic melanoma treated with Ipi between 2009 and 2015 were included. Body composition was assessed by computed tomography at baseline and after four cycles of Ipi. Sarcopenia and low muscle attenuation (MA) were defined using published cut-points. All adverse events (AEs) and immune-related AEs (irAEs) were recorded (Common Terminology Criteria For Adverse Event V.4.0).Results:Eighty-four patients were included in this study (62% male, median age 54 years). At baseline, 24% were sarcopenic and 33% had low MA. On multivariate analysis, sarcopenia and low MA were significantly associated with high-grade AEs (OR=5.34, 95% CI: 1.15–24.88, P=0.033; OR=5.23, 95% CI: 1.41–19.30, P=0.013, respectively), and low MA was associated with high-grade irAEs (OR=3.57, 95% CI: 1.09–11.77, P=0.036). Longitudinal analysis (n=59) revealed significant reductions in skeletal muscle area (SMA), total body fat-free mass, fat mass (all P<0.001) and MA (P=0.030). Mean reduction in SMA was 3.3%/100 days (95% CI: −4.48 to −1.79%, P<0.001). A loss of SMA ⩾7.5%/100 days (highest quartile) was a significant predictor of overall survival in multivariable Cox regression analysis (HR: 2.1, 95% CI: 1.02–4.56, P=0.046).Conclusions:Patients with sarcopenia and low MA are more likely to experience severe treatment-related toxicity to Ipi. Loss of muscle during treatment was predictive of worse survival. Treatments to increase muscle mass and influence outcome warrant further investigation.

Image-Guided Percutaneous Splenic Biopsy and Drainage

Percutaneous splenic biopsy and drainage are relatively safe and accurate procedures. The risk of major complication (1.3%) following percutaneous splenic biopsy does not exceed that of other solid intra-abdominal organ biopsies, and it has less morbidity and mortality than splenectomy. Both computed tomography and ultrasound can be used to provide image guidance for biopsy and drainage. The safety profile of fine-needle aspiration cytology is better than core needle biopsy, but core biopsy has superior diagnostic accuracy.

Optimizing parameters of an open-source airway segmentation algorithm using different CT images

Background Computed tomography (CT) helps physicians locate and diagnose pathological conditions. In some conditions, having an airway segmentation method which facilitates reconstruction of the airway from chest CT images can help hugely in the assessment of lung diseases. Many efforts have been made to develop airway segmentation algorithms, but methods are usually not optimized to be reliable across different CT scan parameters.MethodsIn this paper, we present a simple and reliable semi-automatic algorithm which can segment tracheal and bronchial anatomy using the open-source 3D Slicer platform. The method is based on a region growing approach where trachea, right and left bronchi are cropped and segmented independently using three different thresholds. The algorithm and its parameters have been optimized to be efficient across different CT scan acquisition parameters. The performance of the proposed method has been evaluated on EXACT’09 cases and local clinical cases as well as on a breathing pig lung phantom using multiple scans and changing parameters. In particular, to investigate multiple scan parameters reconstruction kernel, radiation dose and slice thickness have been considered. Volume, branch count, branch length and leakage presence have been evaluated. A new method for leakage evaluation has been developed and correlation between segmentation metrics and CT acquisition parameters has been considered.ResultsAll the considered cases have been segmented successfully with good results in terms of leakage presence. Results on clinical data are comparable to other teams’ methods, as obtained by evaluation against the EXACT09 challenge, whereas results obtained from the phantom prove the reliability of the method across multiple CT platforms and acquisition parameters. As expected, slice thickness is the parameter affecting the results the most, whereas reconstruction kernel and radiation dose seem not to particularly affect airway segmentation.ConclusionThe system represents the first open-source airway segmentation platform. The quantitative evaluation approach presented represents the first repeatable system evaluation tool for like-for-like comparison between different airway segmentation platforms. Results suggest that the algorithm can be considered stable across multiple CT platforms and acquisition parameters and can be considered as a starting point for the development of a complete airway segmentation algorithm.

Model-Based Iterative Reconstruction in CT Enterography

OBJECTIVE The purpose of this study was to analyze the performance of pure model-based iterative reconstruction (MBIR) in low-dose CT enterography. SUBJECTS AND METHODS Forty-four patients with Crohn disease referred for CT enterography were included. Low-dose modified-protocol and conventional-protocol CT datasets were contemporaneously acquired. Conventional-protocol image formation was performed with 40% adaptive statistical iterative reconstruction (ASIR). Modified-protocol data were reconstructed with 100% MBIR and 40% ASIR. Image quality was assessed subjectively and objectively at six levels. Independent clinical interpretations by two fully blinded radiologists were compared with reference standard consensus reviews by two nonblinded readers who had access to clinical information, previous imaging studies, and medical records. RESULTS A 74.7% average radiation dose reduction was seen: low-dose modified-protocol effective dose, 1.61 ± 1.18 mSv (size-specific-dose-estimate, 2.47 ± 1.21 mGy); conventional-protocol effective dose, 6.05 ± 2.84 mSv (size-specific-dose-estimate, 9.25 ± 2.9 mGy). Image quality assessment yielded 9372 data points. Objective noise on modified-protocol MBIR images was superior (p < 0.05) to that with the conventional protocol at three of six levels and comparable at the other three levels. Modified-protocol images were superior to conventional-protocol ASIR images (p < 0.05 in all cases) for subjective noise, spatial resolution, contrast resolution, streak artifact, and diagnostic acceptability on coronal reconstructions. Axial diagnostic acceptability was superior for conventional-protocol ASIR (p = 0.76). For both readers, modified-protocol MBIR clinical readings agreed more closely with reference standard readings than did conventional-protocol ASIR readings with regard to bowel wall disease assessment (κ = 0.589 and 0.700 vs 0.583 and 0.564). Overall Crohn disease activity grade (κ = 0.549 and 0.441 vs 0.315 and 0.596) and detection of acute complications (κ = 1.0 and 0.689 vs 0.896 and 0.896) were comparable when evaluated on conventional-protocol ASIR and modified-protocol MBIR images. CONCLUSION Low-dose CT enterography with MBIR yields images that are comparable to or superior to conventional images.

Comparison of MRI and high-resolution transvaginal sonography for the local staging of cervical cancer.

The aim of this prospective study was to compare the diagnostic accuracy of transvaginal sonography (TVS) with that of MRI in the local staging of cervical cancer.

CORK Study in Cystic Fibrosis: Sustained Improvements in Ultra-Low-Dose Chest CT Scores After CFTR Modulation With Ivacaftor

Background Ivacaftor produces significant clinical benefit in patients with cystic fibrosis (CF) with the G551D mutation. Prevalence of this mutation at the Cork CF Centre is 23%. This study assessed the impact of cystic fibrosis transmembrane conductance regulator modulation on multiple modalities of patient assessment. Methods Thirty‐three patients with the G551D mutation were assessed at baseline and prospectively every 3 months for 1 year after initiation of ivacaftor. Change in ultra‐low‐dose chest CT scans, blood inflammatory mediators, and the sputum microbiome were assessed. Results Significant improvements in FEV1, BMI, and sweat chloride levels were observed post‐ivacaftor treatment. Improvement in ultra‐low‐dose CT imaging scores were observed after treatment, with significant mean reductions in total Bhalla score (P < .01), peribronchial thickening (P = .035), and extent of mucous plugging (P < .001). Reductions in circulating inflammatory markers, including interleukin (IL)‐1&bgr;, IL‐6, and IL‐8 were demonstrated. There was a 30% reduction in the relative abundance of Pseudomonas species and an increase in the relative abundance of bacteria associated with more stable community structures. Posttreatment community richness increased significantly (P = .03). Conclusions Early and sustained improvements on ultra‐low‐dose CT scores suggest it may be a useful method of evaluating treatment response. It paralleled improvement in symptoms, circulating inflammatory markers, and changes in the lung microbiota.

Computed tomography and patient risk: Facts, perceptions and uncertainties

Since its introduction in the 1970s, computed tomography (CT) has revolutionized diagnostic decision-making. One of the major concerns associated with the widespread use of CT is the associated increased radiation exposure incurred by patients. The link between ionizing radiation and the subsequent development of neoplasia has been largely based on extrapolating data from studies of survivors of the atomic bombs dropped in Japan in 1945 and on assessments of the increased relative risk of neoplasia in those occupationally exposed to radiation within the nuclear industry. However, the association between exposure to low-dose radiation from diagnostic imaging examinations and oncogenesis remains unclear. With improved technology, significant advances have already been achieved with regards to radiation dose reduction. There are several dose optimization strategies available that may be readily employed including omitting unnecessary images at the ends of acquired series, minimizing the number of phases acquired, and the use of automated exposure control as opposed to fixed tube current techniques. In addition, new image reconstruction techniques that reduce radiation dose have been developed in recent years with promising results. These techniques use iterative reconstruction algorithms to attain diagnostic quality images with reduced image noise at lower radiation doses.

Castleman Disease: An Unexpected Cause of a Solitary Pleural Mass

Castleman disease (CD) is a rare benign lymphoproliferative disorder, the etiology of which is unclear. Clinically it may manifest as localized disease (unicentric) or disseminated disease (multicentric). CD occurs in the thorax in 70% of cases, abdomen and pelvis in 15%, and in the neck in 10–15% of cases. We present a case of a pleural mass located posteriorly in a paraspinal location, which was discovered incidentally in a 50-year-old man and was subsequently resected followed by an unexpected diagnosis of Castleman disease on histological examination. In this report, we review the clinical and histological findings in a rare presentation of Castleman disease and discuss the findings in this case as part of an overall review of the typical radiological findings seen in Castleman disease.

Pure Iterative Reconstruction Improves Image Quality in Computed Tomography of the Abdomen and Pelvis Acquired at Substantially Reduced Radiation Doses in Patients With Active Crohn Disease.

We assessed diagnostic accuracy and image quality of modified protocol (MP) computed tomography (CT) of the abdomen and pelvis reconstructed using pure iterative reconstruction (IR) in patients with Crohn disease (CD). Methods Thirty-four consecutive patients with CD were referred with suspected extramural complications. Two contemporaneous CT datasets were acquired in all patients: standard protocol (SP) and MP. The MP and SP protocols were designed to impart radiation exposures of 10% to 20% and 80% to 90% of routine abdominopelvic CT, respectively. The MP images were reconstructed with model-based IR (MBIR) and adaptive statistical IR (ASIR). Results The MP-CT and SP-CT dose length product were 88 (58) mGy.cm (1.27 [0.87] mSv) and 303 [204] mGy.cm (4.8 [2.99] mSv), respectively (P < 0.001). Median diagnostic acceptability, spatial resolution, and contrast resolution were significantly higher and subjective noise scores were significantly lower on SP-ASIR 40 compared with all MP datasets. There was perfect clinical agreement between MP-MBIR and SP-ASIR 40 images for detection of extramural complications. Conclusions Modified protocol CT using pure IR is feasible for assessment of active CD.

Imaging of Ischemia, Obstruction and Infection in the Abdomen

Intestinal ischemia is a serious condition that continues to be associated with mortalities in excess of 70%. Intestinal obstruction and gastrointestinal tract sepsis are common conditions, accounting for a large proportion of patients admitted to emergency departments with acute abdominal symptoms. This article discusses the imaging methods and key findings of these entities in the emergency radiology department. The article includes imaging examples, diagnostic options, protocol selections, diagnostic criteria, and differential diagnoses.