Kevin P. Murphy

New-Onset Mediastinal and Central Nervous System Sarcoidosis in a Patient with Metastatic Melanoma Undergoing CTLA4 Monoclonal Antibody Treatment

SummaryBackground: Ipilimumab, a cytotoxic monoclonal antibody that inhibits cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), has been established as an effective therapy in the management of advanced melanoma. Immune-mediated adverse events are a common side effect. Case Report: A 37-year-old male patient was diagnosed with nodal and osseous metastatic melanoma 15 months after the initial surgical treatment for lower limb melanoma. Therapy with the anti-CTLA-4 antibody, ipilimumab, was started. Follow-up staging imaging after treatment initiation showed symmetrical bihilar adenopathy. Transbronchial biopsy showed sarcoidosis. The patient had associated systemic symptoms of fatigue, joint pains, anorexia and weight loss. Brain magnetic resonance imaging (MRI), which was performed for the investigation of headaches, showed abnormal enhancing tissue in the sella turcica and adjacent to the pituitary infundibulum, consistent with neurosarcoidosis. The condition was successfully treated with corticosteroids. Conclusions: We report a case of immunotherapy-induced mediastinal/hilar sarcoidosis, with pituitary involvement, mimicking tumour progression. This highlights the need for awareness amongst radiologists and oncologists of the mechanism of action and potential side effects of new immunotherapies.

Adult Abdominal Hernias

Educational Objectives and Key Points. 1. Given that abdominal hernias are a frequent imaging finding, radiologists not only are required to interpret the appearances of abdominal hernias but also should be comfortable with identifying associated complications and postrepair findings. 2. CT is the imaging modality of choice for the assessment of a known adult abdominal hernia in both elective and acute circumstances because of rapid acquisition, capability of multiplanar reconstruction, good spatial resolution, and anatomic depiction with excellent sensitivity for most complications. 3. Ultrasound is useful for adult groin assessment and is the imaging modality of choice for pediatric abdominal wall hernia assessment, whereas MRI is beneficial when there is reasonable concern that a patients symptoms could be attributable to a hernia or a musculoskeletal source. 4. Fluoroscopic herniography is a sensitive radiologic investigation for patients with groin pain in whom a hernia is suspected but in whom a hernia cannot be identified at physical examination. 5. The diagnosis of an internal hernia not only is a challenging clinical diagnosis but also can be difficult to diagnose with imaging: Closed-loop small-bowel obstruction and abnormally located bowel loops relative to normally located small bowel or colon should prompt assessment for an internal hernia.

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.

Feasibility of low-dose CT with model-based iterative image reconstruction in follow-up of patients with testicular cancer

Highlights • Radiologists should endeavour to minimise radiation exposure to patients with testicular cancer.• Iterative reconstruction algorithms permit CT imaging at lower radiation doses.• Image quality for reduced-dose CT–MBIR is at least comparable to conventional dose.• No loss of diagnostic accuracy apparent with reduced-dose CT–MBIR.

Imaging of Cystic Fibrosis and Pediatric Bronchiectasis

1. CT is superior to pulmonary function tests and chest radiography for the assessment and monitoring of cystic fibrosis (CF)-related lung disease and, also, of pediatric bronchiectasis not caused by CF (hereafter referred to as non-CF bronchiectasis). 2. Low-dose CT protocols that impart radiation doses similar to those used in chest radiography are feasible for the surveillance of patients with bronchiectasis. 3. Chest radiography is still most commonly used as the first-line imaging examination of choice for the assessment of acute complications related to bronchiectasis. 4. Pulmonary MRI, with or without the use of inhaled hyperpolarized gas, can be performed to obtain functional information, and, in dedicated centers, it may yield imaging results comparable to those obtained by CT. 5. Gastrointestinal and pancreaticobiliary manifestations of CF are observed with greater frequency in adults, because of increased life expectancy.

Radiographic findings after pubic symphysiotomy: mean time to follow-up of 41.6 years.

BACKGROUND Pubic symphysiotomy is a rarely performed procedure in which the pubic symphysis is divided to facilitate vaginal delivery in cases of obstructed labor. Recently, many obstetricians have shown renewed interest in this procedure. The purpose of this paper is to report the long-term radiographic findings for patients who had undergone pubic symphysiotomy compared with the radiographic appearance of a group of age-matched and parity-matched controls. METHODS This was a retrospective case-control study. Twenty-five women who had previously undergone pubic symphysiotomy for childbirth were compared with twenty-five age-matched and parity-matched controls. The radiographic parameters recorded included pubic symphysis width, pubic symphysis translation, grade of sacroiliac joint osteoarthritis, and presence of parasymphyseal degeneration. RESULTS The mean time to follow-up after symphysiotomy was 41.6 years (range, twenty-two to fifty-five years). The symphysiotomy group had a significantly higher proportion of patients (80%) with high-grade sacroiliac joint osteoarthritis (Grade 3 or 4 according to the Kellgren and Lawrence osteoarthritis scoring system) than the control group (16%) (p < 0.001). Within the symphysiotomy group, patients with high-grade sacroiliac joint osteoarthritis tended to be older, have a longer time to follow-up, and have a larger pubic symphysis width. The control group had a higher prevalence of parasymphyseal degeneration than did the symphysiotomy group (p = 0.011). CONCLUSIONS Late-onset sacroiliac joint osteoarthritis secondary to pelvic instability was a major finding in this study and, to our knowledge, has not been discussed previously in the literature regarding pubic symphysiotomy.

Communication of unexpected and significant findings on chest radiographs with an automated PACS alert system.

PURPOSE An integral part of realizing the enormous potential of imaging in patient care is close communication between radiologists and referring physicians. One key element of this process is the communication of unexpected significant findings. The authors examined the performance of a PACS-based alert system in the appropriate communication of reports containing unexpected significant findings to referring physicians. METHODS A PACS-integrated key word system was developed such that an e-mail was sent to the referring clinician if a radiologist detected a significant unexpected finding. The number, source, and outcome of chest radiographic unexpected findings over a 14-month period were analyzed. The time for response of the referring physician plus time for follow-up were also examined. RESULTS Key words were applied to 158 of the 39,665 chest radiographs (0.4%) obtained during the study period. The emergency department was the most frequent referral location (46.2%). Final diagnostic categories included malignancy (13.9%), benign lesion (49.4%), and no abnormality (20.2%). The average time to acknowledgment by clinicians of notification was 3.1 days, although 57.6% were acknowledged within 24 hours. The mean time interval to the next relevant radiologic investigation was 26 days among the 77.8% of findings that underwent radiologic follow-up. CONCLUSIONS The development of electronic alert systems, which are integrated into PACS, can aid greatly in report communication and eliminate the risk associated with unread reports that contain significant or unexpected findings.

Abdominal Ablation Techniques

W495 Epidemiology Tumor ablation has developed from intratumoral alcohol infiltration, which was first used in the 1980s. There are currently several efficacious techniques available, with (second-generation) MWA fast becoming the most prevalent. Many of the most common abdominal solid organ tumors are amenable to ablation: hepatocellular carcinoma (HCC), colorectal liver metastases, and renal tumors [1–4]. Other solid tumors amenable to ablation include lung, bone, soft-tissue tumors, and nodal neoplasia.

Reduction of Guide Needle Streak Artifact in CT-Guided Biopsy

PURPOSE Computed tomography (CT)-guided core needle biopsy (CNB) can be affected by streak artifact obscuring the needle tip. This study investigates factors that influence the occurrence and severity of streak artifact during CNB. MATERIALS AND METHODS Eight coaxial guide needles of two sizes from two manufacturers with and without stylets were imaged in a CT phantom, with CT reconstructed with adaptive statistical iterative reconstruction and filtered back projection. CNB-related streak artifact was quantified with profile analysis in an image-processing program. Differences between maximum attenuation at the needle tip and minimum attenuation in the streak artifact were compared for each variable. Diagnostic acceptability and streak artifact were subjectively assessed on each phantom image and on 40 clinical CNB procedures by three independent blinded reviewers following training case review. RESULTS Artifact was significantly less with the central stylet removed versus in situ (median, 1,145 HU vs 3,390 HU; P < .001) for all needles, and less for 19-gauge needles versus 17-gauge needles (median, 1,334 HU vs 2,780 HU, respectively; P = .006). There were no differences based on manufacturer (P = .906) or reconstruction algorithm (P = .524). Independent reviews found that streak artifact was significantly reduced when the central stylet was removed (κ = 0.875-1.0; P < .001), and needle tip position was better in cases in which the stylet was removed (κ = 0.231-0.711; P < .001). CONCLUSIONS Streak artifact can be reduced and needle tip visualization improved by confirming final biopsy needle position with the central stylet removed on CT and using smaller-gauge guide needles.

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.