Dorsal wrist ganglion: clinical and imaging correlation in symptomatic population based on high-field MRI.

OBJECTIVES: To determine prevalence in the symptomatic population of dorsal mucoid cysts centered on dorsal capsuloscapholunate septum (DCSS) using high-field magnetic resonance imaging (MRI) for anatomoclinical and epidemiological correlations. MATERIALS AND METHODS: This single-center retrospective study analyzed all 3-Tesla MRIs consecutively performed for painful wrists in 295 patients. Two blinded readers performed measurements. The protocol included T1 spin echo and 3D proton density sequences with fat saturation. Inter-observer reliability was assessed using kappa and intra-class correlation coefficients for cyst detection and volumetry, respectively. Disagreements concerning cyst detection were resolved by a consensus reading. Cyst size, relationship to extrinsic and scapholunate ligaments (SL), continuity of SL, minimum distance to the posterior interosseous nerve (PIN), cyst communication with joint, and anatomical classifications of cysts were analyzed. Correlation tests were performed to assess associations. RESULTS: Two-hundred ninety-five patients (mean age 39.6 +/- 15.6 (standard deviation), 161 males) were evaluated for detection of dorsal wrist cysts identified in 150/295. In this subgroup, the mean age was 38.7 years (15-75), the sex ratio of 0.6 (59% women), and the median volume cyst of 8.7 mm3 (0.52-2555). Cyst detection, volume, and major axis measurements showed very high agreement between observers, respectively, 0.89, 0.96, and 0.91. 42 patients had dorsal SL pain. A weak negative correlation was found between distance to PIN and dorsal SL pain (r = -0.2415; p < 0.05) and a weak positive correlation between Guérini's classification and dorsal SL pain (r = 0.2466; p < 0.05). CONCLUSION: High-field MRI is the modality of choice for the detection, anatomical, and volumetric assessment of dorsal cysts. Preoperative assessment will be aided by the proposed revised anatomical classification. CLINICAL RELEVANCE STATEMENT: High-field MRI is the modality of choice for the anatomical study of dorsal ganglion cysts. It allows the radiologist to accurately describe the anatomical relationships, size, and visibility of the pedicle, essential information for the surgeon's preoperative assessment. KEY POINTS: Dorsal mucoid wrist ganglion is a condition for which prevalence remains to be determined. High-field MRI is a reproducible imaging modality for the detection and assessment of dorsal wrist cysts. High-field MRI has a key role in the preoperative management of dorsal mucoid cysts.

Proposed DRLs for mammography in Switzerland.

The aim of this study is to propose diagnostic reference levels (DRLs) values for mammography in Switzerland. For the data collection, a survey was conducted among a sufficient number of centres, including five University hospitals, several cantonal hospitals, and large private clinics, covering all linguistic regions of Switzerland to be representative of the clinical practice. The data gathered contained the mean glandular dose (MGD), the compressed breast thickness (CBT), the mammography model and the examination parameters for each acquisition. The data collected was sorted into the following categories: 2D or digital breast tomosynthesis (DBT) examination, craniocaudal (CC) or mediolateral oblique (MLO) projection, and eight categories of CBT ranging from 20 mm to 100 mm in 10 mm intervals. A total of 24 762 acquisitions were gathered in 31 centres on 36 mammography units from six manufacturers. The analysis showed that the data reflects the practice in Switzerland. The results revealed that the MGD is larger for DBT than for 2D acquisitions for the same CBT. From 20-30 mm to 90-100 mm of CBT, the 75th percentile of the MGD values obtained increased from 0.81 mGy to 2.55 mGy for 2D CC acquisitions, from 0.83 mGy to 2.96 mGy for 2D MLO acquisitions, from 1.22 mGy to 3.66 mGy for DBT CC acquisitions and from 1.33 mGy to 4.04 mGy for DBT MLO acquisitions. The results of the survey allow us to propose Swiss DRLs for mammography according to the examination type (2D/DBT), projection (CC/MLO) and CBT. The proposed values are very satisfactory in comparison with other studies.

Clinical outcomes of 3T magnetic resonance imaging-guided lumbar and sacral foraminal injections.

PURPOSE: This article evaluates the feasibility, safety, and efficacy of MRI-guided lumbar or sacral nerve root infiltration for chronic back pain. We compared the outcomes of our MRI-guided infiltrations with data from CT-guided infiltrations reported in the literature and explored the potential advantages of MRI guidance. METHOD: Forty-eight MRI-guided nerve root infiltrations were performed using a 3 T MRI machine. The optimal needle path was determined using breathhold T2-weighted sequences, and the needle was advanced under interleaved guidance based on breathhold PD-weighted images. Pain levels were assessed using a numeric rating scale (NRS) before the procedure and up to 5 months after, during follow-up. Procedure success was evaluated by comparing patients' pain levels before and after the infiltration. RESULTS: The MRI-guided infiltrations yielded pain reduction 1 week after the infiltration in 92% of cases, with an average NRS substantial change of 3.9 points. Pain reduction persisted after 5 months for 51% of procedures. No procedure-related complications occurred. The use of a 22G needle and reconstructed subtraction images from T2 FatSat sequences improved the workflow. CONCLUSION: Our study showed that MRI-guided nerve root infiltration is a feasible, safe, and effective treatment option for chronic back pain. Precise positioning of the needle tip and accurate distribution of the injected solution contributed to the effectiveness of MRI-guided infiltration, which appeared to be as accurate as CT-guided procedures. Further research is needed to explore the potential benefits of metal artifact reduction sequences to optimize chronic back pain management.

Development and Validation of a Predictive Model for Internal Hernia After Roux-en-Y Gastric Bypass in a Multicentric Retrospective Cohort: The Swirl, Weight Excess Loss, Liquid Score.

OBJECTIVE: The aim of this study was to develop and validate a prediction score for internal hernia (IH) after Roux-en-Y gastric bypass (RYGB). SUMMARY BACKGROUND DATA: The clinical diagnosis of IH is challenging. A sensitivity of 63% to 92% was reported for computed tomography (CT). METHODS: Consecutive patients admitted for abdominal pain after RYGB and undergoing CT and surgical exploration were included retrospectively. Potential clinical predictors and radiological signs of IH were entered in binary logistic regression analysis to determine a predictive score of surgically confirmed IH in the Geneva training set (January 2006-December 2014), and validated in 3 centers, Geneva (January 2015-December 2017) and Neuchâtel and Strasbourg (January 2012-December 2017). RESULTS: Two hundred twenty-eight patients were included, 80 of whom (35.5%) had surgically confirmed IH, 38 (16.6%) had a negative laparoscopy, and 110 (48.2%) had an alternate diagnosis. In the training set of 61 patients, excess body weight loss >95% (odds ratio [OR] 6.73, 95% confidence interval [CI]: 1.13-39.96), swirl sign (OR 8.93, 95% CI: 2.30-34.70), and free liquid (OR 4.53, 95% CI: 1.08-19.0) were independent predictors of IH. Area under the curve (AUC) of the score was 0.799. In the validation set of 167 patients, AUC was 0.846. A score ≥2 was associated with an IH incidence of 60.7% (34/56), and 5.3% (3/56) had a negative laparoscopy. CONCLUSIONS: The score could be incorporated in the clinical setting. To reduce the risk of delayed IH diagnosis, emergency explorative laparoscopy in patients with a score ≥ 2 should be considered.

Emergency Computed Tomography: How Misinterpretations Vary According to the Periods of the Nightshift?

OBJECTIVE: To evaluate the accuracy of initial computed tomography (CT) interpretations made by radiology residents during nightshifts in the emergency department. METHODS: Preliminary CT reports performed by radiology residents during 120 consecutive nightshifts (08:30 pm to 08:30 am) were reviewed, attendings' final interpretation being the reference standard. Nightshifts were divided into four consecutive periods of 3 hours. Major misinterpretations were related to potentially life-threatening conditions if not treated immediately after CT. The rate of misinterpretations was calculated for all CT examinations, separately for nightshift's periods and for residents' training years. RESULTS: Misinterpretations were recorded in 155 (7.4%) of 2102 CT examinations, 0.6% (13/2102) were major. There were 2.2% (4/186) major misinterpretations that occurred during the last period of the nightshift versus 0.4% (9/1916) during the first periods of the night (P < 0.05). Of all misinterpretations, 8.5% (130/1526) were made by third- and fourth-year residents and 4.3% (25/576) by fifth-year residents (P < 0.005). CONCLUSIONS: Major misinterpretations occur at the end of the nightshift, which may be explained by the fatigue effect. The rate of misinterpretations is lower among fifth-year residents, which may be related to their prior experience in reading emergency cases.

Magnetic resonance imaging-guided lumbar nerve root infiltrations: optimization of an in-house protocol.

BACKGROUND: For the treatment of radicular pain, nerve root infiltrations can be performed under MRI guidance in select, typically younger, patients where repeated CT exams are not desirable due to associated radiation risk, or potential allergic reactions to iodinated contrast medium. METHODS: Fifteen 3 T MRI-guided nerve root infiltrations were performed in 12 patients with a dedicated surface coil combined with the standard spine coil, using a breathhold PD sequence. The needle artifact on the MR images and the distance between the needle tip and the infiltrated nerve root were measured. RESULTS: The distance between the needle tip and the nerve root was 2.1 ± 1.4 mm. The visual artifact width, perpendicular to the needle long axis, was 2.1 ± 0.7 mm. No adverse events were reported. CONCLUSION: This technical note describes the optimization of the procedure in a 3 T magnetic field, including reported procedure time and an assessment of targeting precision.

Quantitative magnetic resonance imaging: differentiating soft tissue implants and fillers used in cosmetic and reconstructive surgery.

OBJECTIVE: To evaluate the value of synthetic magnetic resonance imaging (MRI) and T2 mapping in distinguishing between different types of fillers in soft tissues. MATERIALS AND METHODS: Ex vivo fillers of buttock soft tissues (silicone, collagen, and different types of hyaluronic acid) were scanned using a synthetic MRI sequence at 1.5 and 3 T and an optimized T2 mapping sequence to measure the T2 relaxation times of the fillers ex vivo. Three patients addressed to assess complications with buttock fillers underwent MRI with the standard morphological sequences and an additional synthetic MRI sequence; T2 mapping was not performed for the patients. Two patients had silicone fillers, whereas the exact filler composition for the third patient was unknown. RESULTS: Measurements of T1 and T2 relaxation times of ex vivo fillers at 1.5 and 3 T using synthetic MRI showed that the silicone, collagen, and hyaluronic acid had distinct relaxation time characteristics. In vivo, the synthetic MRI correctly identified silicone in the two patients with known silicone fillers, showing low T1 and T2 values, whereas in the third patient with an unknown filler type, the synthetic MRI suggested a collagen filler, with intermediate relaxation time values. CONCLUSION: Quantitative sequences have the potential to differentiate between filler types in a noninvasive fashion.

Clot-Based Radiomics Predict a Mechanical Thrombectomy Strategy for Successful Recanalization in Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: Mechanical thrombectomy (MTB) is a reference treatment for acute ischemic stroke, with several endovascular strategies currently available. However, no quantitative methods are available for the selection of the best endovascular strategy or to predict the difficulty of clot removal. We aimed to investigate the predictive value of an endovascular strategy based on radiomic features extracted from the clot on preinterventional, noncontrast computed tomography to identify patients with first-attempt recanalization with thromboaspiration and to predict the overall number of passages needed with an MTB device for successful recanalization. METHODS: We performed a study including 2 cohorts of patients admitted to our hospital: a retrospective training cohort (n=109) and a prospective validation cohort (n=47). Thrombi were segmented on noncontrast computed tomography, followed by the automatic computation of 1485 thrombus-related radiomic features. After selection of the relevant features, 2 machine learning models were developed on the training cohort to predict (1) first-attempt recanalization with thromboaspiration and (2) the overall number of passages with MTB devices for successful recanalization. The performance of the models was evaluated on the prospective validation cohort. RESULTS: A small subset of radiomic features (n=9) was predictive of first-attempt recanalization with thromboaspiration (receiver operating characteristic curve-area under the curve, 0.88). The same subset also predicted the overall number of passages required for successful recanalization (explained variance, 0.70; mean squared error, 0.76; Pearson correlation coefficient, 0.73; P<0.05). CONCLUSIONS: Clot-based radiomics have the ability to predict an MTB strategy for successful recanalization in acute ischemic stroke, thus allowing a potentially better selection of the MTB strategy, as well as patients who are most likely to benefit from the intervention.

Ultrasound Findings in Less Frequent Causes of Carpal Tunnel Syndrome.

The most common etiology of carpal tunnel syndrome (CTS) is idiopathic. However, secondary causes of CTS should be considered when symptoms are unilateral, or electrodiagnostic studies are discrepant with the clinical presentation. Imaging of the carpal tunnel should be performed when secondary causes of CTS are suspected. An ultrasound evaluation of the carpal tunnel can assess for pathologic changes of the median nerve, detect secondary causes of CTS, and aid in surgical planning.

Suspicion of appendicitis in pregnant women: emergency evaluation by sonography and low-dose CT with oral contrast.

OBJECTIVES: To evaluate non-intravenously enhanced low-dose computed tomography with oral contrast (LDCT) for the assessment of pregnant women with right lower quadrant pain, when magnetic resonance imaging (MRI) is not immediately available. METHODS: One hundred and thirty-eight consecutive pregnant women with acute abdominal pain were admitted in our emergency centre. Thirty-seven (27%) of them, with clinical suspicion of acute appendicitis, underwent abdominal ultrasonography (US). No further examination was recommended when US was positive for appendicitis, negative with low clinical suspicion or showed an alternative diagnosis which explained the clinical presentation. All other patients underwent LDCT (<2.5 mSv). Standard intravenously enhanced CT or MRI was performed when LDCT was indeterminate. RESULTS: Eight (22%) of 37 US exams were reported normal, 25 (67%) indeterminate, 1 (3%) positive for appendicitis, 3 (8%) positive for an alternative diagnosis. LDCT was obtained in 29 (78%) patients. It was reported positive for appendicitis in 9 (31%), for alternative diagnosis in 2 (7%), normal in 13 (45%) and indeterminate in 5 (17%). Further imaging (standard CT or MRI) showed appendicitis in 2 of these 5 patients, was truly negative in 1, indeterminate in 1 and falsely positive in 1. An appendicitis was confirmed at surgery in 12 (32%) of the 37 patients. The sensitivity and the specificity of the algorithm for appendicitis were 100% (12/12) and 92% (23/25), respectively. CONCLUSIONS: The proposed algorithm is very sensitive and specific for detection of acute appendicitis in pregnant women; it reduces the need of standard CTs when MRI is not available as second-line imaging. KEY POINTS: • In pregnant women, US is limited by an important number of indeterminate results • Low-dose CT can be used after an inconclusive US for the diagnosis of appendicitis in pregnant women • An algorithm integrating US and low-dose CT is highly sensitive and specific for appendicitis in pregnant women.

The clinical significance of extraluminal air in Hinchey 1a diverticulitis: results from a retrospective cohort study with 10-year follow-up.

BACKGROUND: Some patients with uncomplicated diverticulitis have extraluminal air. Our objective was to determine if patients with Hinchey 1a diverticulitis and isolated extraluminal air present more severe episode than patients without extraluminal air. METHODS: The present study is a monocentric observational retrospective cohort study. Computed tomographies of patients with diagnosed uncomplicated diverticulitis were retrospectively reviewed from the 01 January 2005 to the 31 December 2009. The presence of extraluminal air was determined. Leukocyte count, CRP value, and length of hospitalization were extracted from the patients' files. The follow-up period was from the time of diagnosis to the 15th of March 2019, the latest. Follow-up was censored for death and sigmoidectomy. Recurrence and emergency sigmoidectomy were documented during the follow-up period. The study was performed according to the STROBE guideline. RESULTS: Three hundred and one patients with an episode of Hinchey 1a diverticulitis were included. Extraluminal air was present in 56 patients (18.60%). Leukocyte count (12.4 ± 4.1(G/l) versus 10.7 ± 3.5(G/l), p = 0.05), CRP value (156.9 ± 95.1(mg/l) versus 89.9 ± 74.8(mg/l), p < 0.001), and length of hospital stay (10.9 ± 5.5(days) versus 8.4 ± 3.6(days), p < 0.001) were significantly higher in patients with extraluminal air than in patients without extraluminal air. Seventy-two patients (23.92%) presented a recurrence during the follow-up period. Survival estimates did not differ between patients with or without extraluminal air (p = 0.717). Eleven patients (3.65%) required emergency surgery during the follow-up period. Patients with extraluminal air had shorter emergency surgery-free survival than patients without extraluminal air (p < 0.05). CONCLUSION: The presence of extraluminal air in Hinchey 1a diverticulitis indicates a more severe episode, with higher inflammation parameters at admission, longer length of stay, and an increased risk for emergency sigmoidectomy.

Overuse of plain abdominal radiography in emergency departments: a retrospective cohort study.

BACKGROUND: Plain abdominal radiography (PAR) is routinely performed in emergency departments (EDs). This study aimed to (1) identify the indications for PAR in EDs and compare them against international guidelines, (2) uncover predictors of non-compliance with guidelines, and (3) describe the use of additional radiological examinations in EDs. METHODS: Retrospective cohort study in the EDs of two hospitals in Geneva, Switzerland, including all adult patients who underwent PAR in the EDs. Indications were considered "appropriate" if complying with guidelines. Predictors of non-compliance were identified by univariate and multivariate analyses. RESULTS: Over 1 year, PAR was performed in 1997 patients (2.2% of all admissions). Their mean age was 59.7 years, with 53.1% of female patients. The most common indications were constipation (30.8%), suspected ileus (28.9%), and abdominal pain (15.3%). According to the French and American guidelines, only 11.8% of the PARs were indicated, while 46.2% of them complied with the Australian and British guidelines. On multivariate analysis, admission to the private hospital ED (odds ratio [OR] 3.88, 95% CI 1.78-8.45), female gender (OR 1.95, 95% CI 1.46-2.59), and an age >  65 years (OR 2.41, 95%CI 1.74-3.32) were associated with a higher risk of inappropriate PAR. Additional radiological examinations were performed in 73.7% of patients. CONCLUSIONS: Most indications for PAR did not comply with guidelines and elderly women appeared particularly at risk of being exposed to inappropriate examination. PAR did not prevent the need for additional examinations. Local guidelines should be developed, and initiatives should be implemented to reduce unnecessary PARs. TRIAL REGISTRATION: ClinicalTrials.gov , identifier NCT02980081 .

Diagnosis of Pulmonary Embolism During Pregnancy: A Multicenter Prospective Management Outcome Study.

Background: Data on the optimal diagnostic management of pregnant women with suspected pulmonary embolism (PE) are limited, and guidelines provide inconsistent recommendations on use of diagnostic tests. Objective: To prospectively validate a diagnostic strategy in pregnant women with suspected PE. Design: Multicenter, multinational, prospective diagnostic management outcome study involving pretest clinical probability assessment, high-sensitivity D-dimer testing, bilateral lower limb compression ultrasonography (CUS), and computed tomography pulmonary angiography (CTPA). (ClinicalTrials.gov: NCT00740454). Setting: 11 centers in France and Switzerland between August 2008 and July 2016. Patients: Pregnant women with clinically suspected PE in emergency departments. Intervention: Pulmonary embolism was excluded in patients with a low or intermediate pretest clinical probability and a negative D-dimer result. All others underwent lower limb CUS and, if results were negative, CTPA. A ventilation-perfusion (V/Q) scan was done if CTPA results were inconclusive. Pulmonary embolism was excluded if results of the diagnostic work-up were negative, and untreated pregnant women had clinical follow-up at 3 months. Measurements: The primary outcome was the rate of adjudicated venous thromboembolic events during the 3-month follow-up. Results: 441 women were assessed for eligibility, and 395 were included in the study. Among these, PE was diagnosed in 28 (7.1%) (proximal deep venous thrombosis found on ultrasonography [n = 7], positive CTPA result [n = 19], and high-probability V/Q scan [n = 2]) and excluded in 367 (clinical probability and negative D-dimer result [n = 46], negative CTPA result [n = 290], normal or low-probability V/Q scan [n = 17], and other reason [n = 14]). Twenty-two women received extended anticoagulation during follow-up, mainly for previous venous thromboembolic disease. The rate of symptomatic venous thromboembolic events was 0.0% (95% CI, 0.0% to 1.0%) among untreated women after exclusion of PE on the basis of negative results on the diagnostic work-up. Limitation: There were several protocol deviations, reflecting the difficulty of performing studies in pregnant women with suspected PE. Conclusion: A diagnostic strategy based on assessment of clinical probability, D-dimer measurement, CUS, and CTPA can safely rule out PE in pregnant women. Primary Funding Source: Swiss National Foundation for Scientific Research, Groupe d'Etude de la Thrombose de Bretagne Occidentale, and International Society on Thrombosis and Haemostasis.

Femoral head subchondral impaction on CT: what does it mean in patients with acetabular fracture?

OBJECTIVE: To evaluate the prevalence of isolated femoral head impactions associated with acetabular fractures and to assess whether impactions may be predictive of the development of delayed major complications requiring total hip arthroplasty. MATERIALS AND METHODS: A total of 128 consecutive adult patients with acetabular fracture and no femoral head fracture were included. Admission CTs were re-interpreted for the presence of hip dislocation and femoral head impactions. Radiological and clinical reports were reviewed in patients in whom conservative management of the femoral head was attempted, to determine if total hip arthroplasty was eventually required over a 48-month follow-up period. Univariate and multivariate analyses were performed to assess whether impaction is an independent predictor of failure of conservative management. RESULTS: Impaction was found in 40% of all patients (51 out of 128), in 58% of those with dislocation (19 out of 33), and in 34% of those without dislocation (32 out of 95; p < 0.05). One hundred and five patients underwent conservative management of the femoral head; 12.5% of them (13 out of 105) eventually required total hip arthroplasty. An impaction was present in 77% of the latter (10 out of 13) and in 33% of patients with successful conservative management (30 out of 92; p = 0.0042). At multivariate analysis, impaction and dislocation were significantly and independently associated with a higher risk for delayed total hip arthroplasty (odds ratio of 4.8 and 4.0 respectively). CONCLUSION: Femoral head impactions are frequently seen on CT of patients with acetabular fractures; they are independent predictive factors for the need for delayed total hip arthroplasty. They should be systematically mentioned in the CT report.

Concomitant leukocytosis and lymphopenia predict significant pathology at CT of acute abdomen: a case-control study.

BACKGROUND: Acute abdominal pain accounts for about 10% of emergency department visits and has progressively become the primary indication for CT scanning in most centers. The goal of our study is to identify biological or clinical variables able to predict or rule out significant pathology (conditions requiring urgent medical or surgical treatment) on abdominal CT in patients presenting to an emergency department with acute abdominal pain. METHODS: This was a retrospective cohort study performed in the emergency department of an academic center with an annual census of 60'000 patients. One hundred and-nine consecutive patients presenting with an acute non-traumatic abdominal pain, not suspected of appendicitis or renal colic, during the first semester of 2013, who underwent an abdominal CT were included. Two medical students, completing their last year of medical school, extracted the data from patients' electronic health record. Ambiguities in the formulations of clinical symptoms and signs in the patients' records were solved by consulting a board certified emergency physician. Nine clinical and biological variables were extracted: shock index, peritonism, abnormal bowel sounds, fever (> 38 °C), intensity and duration of the pain, leukocytosis (white blood cell count >11G/L), relative lymphopenia (< 15% of total leukocytes), and C-reactive Protein (CRP). These variables were compared to the CT results (reference standard) to determine their ability to predict a significant pathology. RESULTS: Significant pathology was detected on CT in 71 (65%) patients. Only leukocytosis (odds ratio 3.3, p = 0.008) and relative lymphopenia (odds ratio 3.8, p = 0.002) were associated with significant pathology on CT. The joint presence of these two anomalies was strongly associated with significant pathology on CT (odds ratio 8.2, p = 0.033). Leukocytosis with relative lymphopenia had a specificity of 89% (33/37) and sensitivity of 48% (33/69) for the detection of significant pathology on CT. CONCLUSION: The high specificity of the association between leukocytosis and relative lymphopenia amongst the study population suggests that these parameters would be sufficient to justify an emergency CT. However, none of the parameters could be used to rule out a significant pathology.

Assessment of CT dose to the fetus and pregnant female patient using patient-specific computational models.

PURPOSE: This work provides detailed estimates of the foetal dose from diagnostic CT imaging of pregnant patients to enable the assessment of the diagnostic benefits considering the associated radiation risks. MATERIALS AND METHODS: To produce realistic biological and physical representations of pregnant patients and the embedded foetus, we developed a methodology for construction of patient-specific voxel-based computational phantoms based on existing standardised hybrid computational pregnant female phantoms. We estimated the maternal absorbed dose and foetal organ dose for 30 pregnant patients referred to the emergency unit of Geneva University Hospital for abdominal CT scans. RESULTS: The effective dose to the mother varied from 1.1 mSv to 2.0 mSv with an average of 1.6 mSv, while commercial dose-tracking software reported an average effective dose of 1.9 mSv (range 1.7-2.3 mSv). The foetal dose normalised to CTDIvol varies between 0.85 and 1.63 with an average of 1.17. CONCLUSION: The methodology for construction of personalised computational models can be exploited to estimate the patient-specific radiation dose from CT imaging procedures. Likewise, the dosimetric data can be used for assessment of the radiation risks to pregnant patients and the foetus from various CT scanning protocols, thus guiding the decision-making process. KEY POINTS: • In CT examinations, the absorbed dose is non-uniformly distributed within foetal organs. • This work reports, for the first time, estimates of foetal organ-level dose. • The foetal brain and skeleton doses present significant correlation with gestational age. • The conceptus dose normalised to CTDI vol varies between 0.85 and 1.63. • The developed methodology is adequate for patient-specific CT radiation dosimetry.

Emergency assessment of patients with acute abdominal pain using low-dose CT with iterative reconstruction: a comparative study.

OBJECTIVES: To determine if radiation dose delivered by contrast-enhanced CT (CECT) for acute abdominal pain can be reduced to the dose administered in abdominal radiography (<2.5 mSv) using low-dose CT (LDCT) with iterative reconstruction algorithms. METHODS: One hundred and fifty-one consecutive patients requiring CECT for acute abdominal pain were included, and their body mass index (BMI) was calculated. CECT was immediately followed by LDCT. LDCT series was processed using 1) 40% iterative reconstruction algorithm blended with filtered back projection (LDCT-IR-FBP) and 2) model-based iterative reconstruction algorithm (LDCT-MBIR). LDCT-IR-FBP and LDCT-MBIR images were reviewed independently by two board-certified radiologists (Raters 1 and 2). RESULTS: Abdominal pathology was revealed on CECT in 120 (79%) patients. In those with BMI <30, accuracies for correct diagnosis by Rater 1 with LDCT-IR-FBP and LDCT-MBIR, when compared to CECT, were 95.4% (104/109) and 99% (108/109), respectively, and 92.7% (101/109) and 100% (109/109) for Rater 2. In patients with BMI ≥30, accuracies with LDCT-IR-FBP and LDCT-MBIR were 88.1% (37/42) and 90.5% (38/42) for Rater 1 and 78.6% (33/42) and 92.9% (39/42) for Rater 2. CONCLUSIONS: The radiation dose delivered by CT to non-obese patients with acute abdominal pain can be safely reduced to levels close to standard radiography using LDCT-MBIR. KEY POINTS: • LDCT-MBIR (<2.5 mSv) can be used to assess acute abdominal pain. • LDCT-MBIR (<2.5 mSv) cannot safely assess acute abdominal pain in obese patients. • LDCT-IR-FBP (<2.5 mSv) cannot safely assess patients with acute abdominal pain.

Non-odontogenic tumors of the facial bones in children and adolescents: role of multiparametric imaging.

Tumors of the pediatric facial skeleton represent a major challenge in clinical practice because they can lead to functional impairment, facial deformation, and long-term disfigurement. Their treatment often requires a multidisciplinary approach, and radiologists play a pivotal role in the diagnosis and management of these lesions. Although rare, pediatric tumors arising in the facial bones comprise a wide spectrum of benign and malignant lesions of osteogenic, fibrogenic, hematopoietic, neurogenic, or epithelial origin. The more common lesions include Langerhans cell histiocytosis and osteoma, while rare lesions include inflammatory myofibroblastic and desmoid tumors; juvenile ossifying fibroma; primary intraosseous lymphoma; Ewing sarcoma; and metastases to the facial bones from neuroblastoma, Ewing sarcoma, or retinoblastoma. This article provides a comprehensive approach for the evaluation of children with non-odontogenic tumors of the facial skeleton. Typical findings are discussed with emphasis on the added value of multimodality multiparametric imaging with computed tomography (CT), magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI), positron emission tomography CT (PET CT), and PET MRI. Key imaging findings and characteristic histologic features of benign and malignant lesions are reviewed and the respective role of each modality for pretherapeutic assessment and post-treatment follow-up. Pitfalls of image interpretation are addressed and how to avoid them.

Emergency Computed Tomography: What is Missed at First Reading?

OBJECTIVES: The aim of this study was to evaluate the accuracy of preliminary computed tomography (CT) interpretations made by radiology residents in the emergency department. METHODS: For 4 periods of 20 consecutive days, attending radiologists prospectively recorded any disparities between their own CT interpretations (reference standard) and the preliminary interpretations of emergency radiology residents. Misinterpretations were defined as major when related to a potentially life-threatening pathology if not immediately managed after CT. The rate of disparities was calculated for all CT examinations, separately for body and neuroradiological cases, and for working and on-call hours. RESULTS: A total of 3044 emergency CT examinations were performed during the survey: 1568 (51%) body scans and 1476 (49%) neurological scans. Disparities were reported in 145 (4.8%) of all CT examinations, with 0.8% (24/3044) defined as major misinterpretations. There were 100 (6.3%) of 1568 disparities in body CT versus 45 (3.0%) of 1476 in neurological CT examinations (P = 0.001). No significant differences were found between disparities recorded during regular working hours (47/1083 [4.3%]) versus on-call hours (98/1961 [5.0%], P = 0.47). CONCLUSIONS: There were typically more disparities between resident and attending interpretations in emergency body CT. Major disparities represented only a small proportion of all misinterpretations. The detailed analysis of our data enables benchmarking over time and offers a reference for optimizing the training of residents in emergency radiology.

Illegal intra-corporeal packets: can dual energy CT be used for the evaluation of cocaine concentration? A cross sectional study.

BACKGROUND: The recent implementation of the dual energy technology on CT-scanners has opened new perspectives in tissue and material characterization. This study aims to evaluate whether dual energy CT can be used to assess the concentration of cocaine of intra-intestinal illegal packets. METHODS: The study was approved by the institutional review board of our institution (CER 13_027_R). From November 2010 to May 2013, all consecutive conveyors in whom a low-dose abdominal CT (LDCT) revealed the presence of illegal intra-corporeal drug packets underwent a dual energy CT series (gemstone spectral imaging) targeted on one container. The mean radiological density (HU) of these packets was measured on the LDCT series, and on the monochromatic dual energy series, at 40 and 140 keV. The difference between the HU at 40 and 140 keV was reported as ∆HU. The effective atomic number Z(eff) was also measured on the monochromatic series. A chemical analysis was performed after expulsion to select cocaine containing packets, and to determine their cocaine concentrations. A correlation analysis was performed between HU, ∆HU and Z(eff), with regard to the percentage of cocaine. RESULTS: Fifty-four cocaine conveyors were included. The mean cocaine content of the packets was 36.8% (range 11.2-80, SD 15.4), the mean radiologic density 105 HU, the mean Z(eff) 8.7 and the mean ∆HU 163. The cocaine content was correlated with the ∆HU (0.57, p < 0.001), with the Z(eff) (r = 0.56, p < 0.001) but not with radiologic density (r = 0.25, p = 0.064). ∆HU >200 was 0.9 (9 of 10) sensitive and 0.82 (36 of 44) specific to predict a cocaine concentration higher than 50%. CONCLUSION: Measuring ∆HU or Z(eff) on dual energy monochromatic CT series can be used to detect ingested packets with cocaine concentration >50%.