Intravenous Contrast Medium Research Articles

Understanding of Saudi Population on the Usage of Intravenous Contrast Media Injections in Radiology

Background: Intravenous contrast media (IVCM) in radiology are extremely important for accurate diagnosis and are used daily all over the globe. These contract media are very safe if administered correctly. However, adverse events have also been reported. This study was undertaken to determine the understanding of the patients towards the usage of IVCM in radiology. Methods: This is a cross-sectional study conducted on patients recommended for IVCM-mediated radiological examinations. The data were collected by face-to-face interactions using the self-administered questionnaire before IVCM administration. The questionnaire was all about patient’s information for IVCM usage, their associated benefits and risks. Results: Out of 225 patients who participated, a majority (72%) had insufficient knowledge of IVCM-associated risks and benefits. Both male and female patients showed a similar understanding of IVCM (p>0.05). Educated patients showed better understanding than uneducated patients (p<0.001). Similarly, employed patients demonstrated a higher level of understanding of IVCMs compared to unemployed patients (p<0.05). Moreover, 63.5%, 45.3% and 62.2% of patients believed that IVCM caused cancer, cardiovascular disorders, and adverse allergic reactions, respectively. Moreover, 52.4%, 33.3% and 49.3% of patients believed that IVCM caused shortness in breath, loss of consciousness and increase of heart rate, respectively. In addition, 29.3%, 62.2% and 20.0% of patients also advised diarrhea, itching and convulsion, respectively. Conclusion: Overall, patients’ knowledge was unsatisfactory for understanding contrast media in radiology. This study recommends that the Ministry of Health, Saudi Arabia, should arrange frequent awareness programs on contrast media in Qassim.

Contrast-associated acute kidney injury following intravenous contrast media computed tomography; new concept and future directions: A systematic review study on emergencies patients

Introduction: Computed tomography (CT) is a key method for various disorders. Image can be more quality with intravenous contrast media, however in some cases may be accompanied by a risk of kidney impairment. Objectives: This study aimed to investigate the association between acute kidney injury incidence and intravenous contrast media for CT in emergency patients. Methods and Materials: Search strategies were performed using standard keywords across international databases such as Web of Science, Scopus, Cochrane, PubMed, and Embase. Dimension, OpenGrey, DOAJ, CINAHL, and Google Scholar search engines were searched for a complete search. Additionally, manual searching was conducted using the references of related articles. Studies that reported the correlation between acute kidney injury incidence and intravenous contrast media were included in this systematic review. Results: First, 1185 studies were identified. After duplication, 533 studies remained and 417 were excluded. Out of 116 evaluated studies for retrieval, 49 were eliminated and 67 were assessed for eligibility. Ultimately, 28 studies with 48878 patients were included in the final review. Most of the studies were retrospective cohorts and have found no significant correlation between the incidence of acute kidney injury and intravenous contrast media administration (ICMA) for CT. Conclusion: Intravenous contrast media with a conventional dose for CT does not cause acute kidney injury unless in the presence of a particular condition. Registration: This study was compiled following the PRISMA checklist and its protocol was registered on the PROSPERO (CRD42023448461) and Research Registry (UIN: reviewregistry1690) websites.

Case 324.

A 69-year-old right-handed man with a history of substance use disorder, hypertension, and diabetes presented to the emergency department in an unresponsive state. Upon examination, apart from tachycardia (heart rate, 108 beats per minute), vital signs were within normal ranges (blood pressure, 134/102 mm Hg; temperature, 97.9°F [36.6°C]; respiratory rate, 16 breaths per minute; oxygen saturation, 96%). He had a Glasgow coma scale score of 8. Otherwise, the physical examination revealed no abnormalities. His prior psychiatric and surgical histories were unremarkable. There was no history of recent travel, camping, hiking, or vaccination. No family history could be obtained. Laboratory work-up revealed an elevated creatine kinase level (49 006 U/L [818.4 μkat/L]; normal reference range, 10-205 U/L [0.17-3.42 μkat/L]). An electrocardiogram showed sinus tachycardia without evidence of cardiac ischemia. An echocardiogram was unremarkable. Alanine aminotransferase (126 U/L [2.10 μkat/L]; normal reference range, 0-40 U/L [0-0.67 μkat/L]) and aspartate aminotransferase (488 U/L [8.15 μkat/L]; normal reference range, 3-44 U/L [0.05-0.74 μkat/L]) levels were elevated. Polymerase chain reaction results were negative for HIV-1, HIV-2, syphilis treponemal, and COVID-19 antibodies. The rest of the routine laboratory work-up findings were within normal limits. Urine drug screening was positive for cocaine, marijuana, fentanyl, and benzodiazepines. Naloxone was administered, but the patient remained unresponsive. Intubation was performed for airway protection. Noncontrast and contrast-enhanced CT of the head (Fig 1) and CT angiography were performed in the emergency department to rule out an acute intracranial abnormality. Multisequence MRI of the brain with administration of intravenous contrast material was ordered for further assessment (Figs 2-4). CT of the abdomen and pelvis was unremarkable (images not shown).

False-Positive and False-Negative Contrast-enhanced Mammograms: Pitfalls and Strategies to Improve Cancer Detection.

Contrast-enhanced mammography (CEM) is a relatively new breast imaging modality that uses intravenous contrast material to increase detection of breast cancer. CEM combines the structural information of conventional mammography with the functional information of tumor neovascularity. Initial studies have demonstrated that CEM and MRI perform with similar accuracies, with CEM having a slightly higher specificity (fewer false positives), although larger studies are needed. There are various reasons for false positives and false negatives at CEM. False positives at CEM can be caused by benign lesions with vascularity, including benign tumors, infection or inflammation, benign lesions in the skin, and imaging artifacts. False negatives at CEM can be attributed to incomplete or inadequate visualization of lesions, marked background parenchymal enhancement (BPE) obscuring cancer, lack of lesion contrast enhancement due to technical issues or less-vascular cancers, artifacts, and errors of lesion perception or characterization. When possible, real-time interpretation of CEM studies is ideal. If additional views are necessary, they may be obtained while contrast material is still in the breast parenchyma. Until recently, a limitation of CEM was the lack of CEM-guided biopsy capability. However, in 2020, the U.S. Food and Drug Administration cleared two devices to support CEM-guided biopsy using a stereotactic biopsy technique. The authors review various causes of false-positive and false-negative contrast-enhanced mammograms and discuss strategies to reduce these diagnostic errors to improve cancer detection while mitigating unnecessary additional imaging and procedures. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Infection prevention and control in CT Part 2: Radiographers' and radiology nurses' perceptions of high-risk scenarios contributing to non-adherence to IPC protocols

IntroductionAdherence to standard and transmission-based precautions in the computed tomography (CT) setting is central to effective infection prevention and control (IPC), yet there is limited evidence about medical imaging (MI) professionals' self-reported predictors of IPC breaches. This is the second of a two-part series on IPC in the CT setting. Part 1 reported on Australian baseline data relating to intravenous contrast media administration and power injectors. Part 2 presents Australian radiographers' and radiology nurses' perceptions of clinical situations that reduce adherence to standard and transmission-based precautions in CT. MethodsA self-administered survey was distributed to Australian radiographers and radiology nurses working in CT. Responses to an open-ended question “If I was to not adhere to the standard and transmission-based precautions in the CT department, it is most likely when …” was analysed using inductive coding for themes, followed by deductive analysis mapped to the Systems Engineering Initiative for Patient Safety (SEIPS) model. ResultsStudy participants (n = 136) were radiographers (n = 119; 87.5%) and nurses (n = 17; 12.5%). ‘Four themes were derived from the inductive analysis: (1) high-risk working conditions, (2) compliance with good practice, (3) attitudes and practice, and (4) quality of communication. Deductive analysis, using the SEIPS domains revealed that predominant issues related to ‘Tasks’ (43.7%) and ‘Organisation’ (30.6%) followed by issues related to ‘Person’ (16.9%), ‘Tools and technology’ (6.9%) and ‘Environment’ (1.9%). ConclusionMulti-faceted pressures on radiology staff may compromise adherence to standard and transmission-based precautions in CT. Task difficulty, time pressures whilst undertaking tasks, and reduced staffing could lead to lower adherence to standard and transmission-based precautions. Implications for practiceFuture studies that focus on evaluation of ‘Tasks’ and ‘Organisation’ domains of the SEIPS model may provide further insights to non-adherence behaviours in MI.

Infection prevention and control in CT Part 1: An Australian study of roles, responsibilities and practices

IntroductionThe computed tomography (CT) suite presents Infection Prevention and Control (IPC) risks for staff and patients. This is the first of a two-part series on IPC in the CT setting and reports on Australian baseline data related to intravenous contrast media administration and the use of power injectors in the CT suite, including knowledge sources related to the delivery of contrast media. The second part provides insights into CT staff's perceptions of high-risk scenarios for non-adherence to standard or transmission-based precautions. MethodsThe study employed an online survey design, directed at radiographers and radiology nurses working in Australia. The survey included questions relating to CT workplace staffing and equipment, contrast media use and occupational roles, and knowledge sources used for infection control and contrast injectors. ResultsOverall, 160 study participants completed the survey (radiographers: n = 138, 86.3%; nurses: n = 22, 13.7%). Differences were identified between public and private practice. Public hospitals completed more contrast-enhanced scans, and with dual injecting systems, operated and cleaned by radiographers and nurses. Private clinics generally used single-system, power injectors. Radiographers and nurses relied heavily on their colleagues and product guidelines for IPC information. IPC teams were uncommon in private clinics, very common in public departments and 50% of respondents had undertaken IPC training in the last 12 months. ConclusionInsights into use and duties of professionals delivering intravenous contrast media administration using power injectors in the CT suite will help to inform decision-making processes on IPC education strategies and map risk. Implication for practiceFuture research should focus on how radiology workers in CT perceive IPC risk and/or might vary from best practice, which has direct clinical implications for safety if contamination, or incorrect information is routinely applied.

Outcomes of Intravenous Contrast Media on Patients with CKD: Systematic Review and Meta-Analysis

Outcomes of Intravenous Contrast Media on Patients with CKD: Systematic Review and Meta-Analysis

Does Liver MRI Require Intravenous Contrast Medium

Purpose: The aim of this study was to evaluate if and for which indications intravenous contrast medium (CM) is required in liver MRI.

Correcting Posterior Paraspinal Muscle Computed Tomography Density for Intravenous Contrast Material Independent of Sex and Vascular Phase.

Intravenous contrast poses challenges to computed tomography (CT) muscle density analysis. We developed and tested corrections for contrast-enhanced CT muscle density to improve muscle analysis and the utility of CT scans for the assessment of myosteatosis. Using retrospective images from 240 adults who received routine abdominal CT imaging from March to November 2020 with weight-based iodine contrast, we obtained paraspinal muscle density measurements from noncontrast (NC), arterial, and venous-phase images. We used a calibration sample to develop 9 different mean and regression-based corrections for the effect of contrast. We applied the corrections in a validation sample and conducted equivalence testing. We evaluated 140 patients (mean age 52.0y [SD: 18.3]; 60% female) in the calibration sample and 100 patients (mean age 54.8y [SD: 18.9]; 60% female) in the validation sample. Contrast-enhanced muscle density was higher than NC by 8.6HU (SD: 6.2) for the arterial phase (female, 10.4HU [SD: 5.7]; male, 6.0HU [SD:6.0]) and by 6.4HU [SD:8.1] for the venous phase (female, 8.0HU [SD: 8.6]; male, 4.0HU [SD: 6.6]). Corrected contrast-enhanced and NC muscle density was equivalent within 3HU for all correctionns. The -7.5HU correction, independent of sex and phase, performed well for arterial (95% CI: -0.18, 1.80HU) and venous-phase data (95% CI: -0.88, 1.41HU). Our validated correction factor of -7.5HU renders contrast-enhanced muscle density statistically similar to NC density and is a feasible rule-of-thumb for clinicians to implement.

Case 317: Adult-Onset Leukoencephalopathy with Axonal Spheroids and Pigmented Glia.

A 44-year-old previously healthy man with a 9-month history of progressive cognitive decline, depression, urinary incontinence, and inability to perform tasks of daily living presented to the emergency department with worsening cognitive and neuropsychiatric symptoms. He had become more distressed, and his family noticed him departing the house without closing doors, leaving water faucets running, and sending his children to school on Sundays. History taken from the patient's wife revealed that his brother had passed away in his late 30s after a slowly progressing functional and cognitive decline over the course of 5 years. No further detailed family history could be obtained. The review of systems was negative; he had no prior medical, psychiatric, or surgical history; and he denied any history of recent travel, camping, hiking, or vaccination. The patient was not taking any dietary supplements, nor was he taking any over-the-counter or prescription medication. Examination revealed vital signs were within normal limits. Neurocognitive assessment revealed a conscious, coherent, and alert patient with impaired memory and concentration. He showed poor attention, depressed mood, and restricted affect. He was unable to spell the word world forward, nor was he able to understand a request to spell it backward. The rest of the physical and neurologic examination revealed no abnormalities. Extensive laboratory work-up was conducted and included the following: toxicology screening; screening for HIV-1, HIV-2, and syphilis treponemal antibodies; COVID-19 polymerase chain reaction; and measurement of B1 and B12 levels. The results of screening were negative. Cerebrospinal fluid (CSF) assays, including CSF oligoclonal bands and CSF flow cytometry, revealed values within normal limits. CT of the brain without intravenous contrast material was performed in the emergency department to rule out acute intracranial abnormality. Multiplanar multisequence MRI of the brain without and with intravenous contrast material was ordered for further assessment. CT images of chest, abdomen, and pelvis were unremarkable (images not shown).

Long-term reproducibility of opportunistically assessed vertebral bone mineral density and texture features in routine clinical multi-detector computed tomography using an automated segmentation framework.

To investigate reproducibility of texture features and volumetric bone mineral density (vBMD) extracted from trabecular bone in the thoracolumbar spine in routine clinical multi-detector computed tomography (MDCT) data in a single scanner environment. Patients who underwent two routine clinical thoraco-abdominal MDCT exams at a single scanner with a time interval of 6 to 26 months (n=203, 131 males; time interval mean, 13 months; median, 12 months) were included in this observational study. Exclusion criteria were metabolic and hematological disorders, bone metastases, use of bone-active medications, and history of osteoporotic vertebral fractures (VFs) or prior diagnosis of osteoporosis. A convolutional neural network (CNN)-based framework was used for automated spine labeling and segmentation (T5-L5), asynchronous Hounsfield unit (HU)-to-BMD calibration, and correction for the intravenous contrast medium phase. Vertebral vBMD and six texture features [varianceglobal, entropy, short-run emphasis (SRE), long-run emphasis (LRE), run-length non-uniformity (RLN), and run percentage (RP)] were extracted for mid- (T5-T8) and lower thoracic (T9-T12), and lumbar vertebrae (L1-L5), respectively. Relative annual changes were calculated in texture features and vBMD for each vertebral level and sorted by sex, and changes were checked for statistical significance (P<0.05) using paired t-tests. Root mean square coefficient of variation (RMSCV) and root mean square error (RMSE) were calculated as measures of variability. SRE, LRE, RLN, and RP exhibited substantial reproducibility with RMSCV-values below 2%, for both sexes and at all spine levels, while vBMD was less reproducible (RMSCV =11.9-16.2%). Entropy showed highest variability (RMSCV =4.34-7.69%) due to statistically significant increases [range, mean ± standard deviation: (4.40±5.78)% to (8.36±8.66)%, P<0.001]. RMSCV of varianceglobal ranged from 1.60% to 3.03%. Opportunistic assessment of texture features in a single scanner environment using the presented CNN-based framework yields substantial reproducibility, outperforming vBMD reproducibility. Lowest scan-rescan variability was found for higher-order texture features. Further studies are warranted to determine, whether microarchitectural changes to the trabecular bone may be assessed through texture features.

Artificial intelligence tool detection of intravenous contrast enhancement using spleen attenuation.

To assess the ability of an automated AI tool to detect intravenous contrast material (IVCM) in abdominal CT examinations using spleen attenuation. A previously validated automated AI tool measuring the attenuation of the spleen was deployed on a sample of 32,994 adult (age ≥ 18) patients (mean age, 61.9 ± 14.7 years; 13,869 men, 19,125 women) undergoing 65,449 supine position CT examinations (41,020 with and 24,429 without IVCM by DICOM header) from January 1, 2000 to December 31, 2021. After exclusions, receiver operating characteristic (ROC) curve analysis was performed to determine the optimal threshold for binary classification of IVCM status (non-contrast vs IVCM enhanced), which was then applied to the sample. Discordant examinations (i.e., IVCM status determined by AI tool did not match DICOM header) were manually reviewed to establish ground truth. Repeat ROC curve and contingency table analysis were performed to assess AI tool performance. ROC analysis of the initial study sample of 61,783 CT examinations yielded AUC of 0.970 with Youden index suggesting an optimal spleen attenuation threshold of 65 Hounsfield units (HU). Manual review of 2094 discordant CT examinations revealed discordance due to DICOM header error in 1278 (61.0%) and AI tool misclassification in 410 (19.6%), with 406 (9.4%) meeting exclusion criteria. Analysis of 61,377 CT examinations in the final study sample yielded AUC of 0.999 with accuracy of 99.3% at the 65 HU threshold. Error rate for DICOM header information was 2.1% (1278/61,377) versus 0.7% (410/61,377) for the AI tool. The automated spleen attenuation AI tool was highly accurate for detection of IVCM at a threshold of 65 HU.

Machine Learning Classification of Body Part, Imaging Axis, and Intravenous Contrast Enhancement on CT Imaging.

Purpose: The development and evaluation of machine learning models that automatically identify the body part(s) imaged, axis of imaging, and the presence of intravenous contrast material of a CT series of images. Methods: This retrospective study included 6955 series from 1198 studies (501 female, 697 males, mean age 56.5years) obtained between January 2010 and September 2021. Each series was annotated by a trained board-certified radiologist with labels consisting of 16 body parts, 3 imaging axes, and whether an intravenous contrast agent was used. The studies were randomly assigned to the training, validation and testing sets with a proportion of 70%, 20% and 10%, respectively, to develop a 3D deep neural network for each classification task. External validation was conducted with a total of 35,272 series from 7 publicly available datasets. The classification accuracy for each series was independently assessed for each task to evaluate model performance. Results: The accuracies for identifying the body parts, imaging axes, and the presence of intravenous contrast were 96.0% (95% CI: 94.6%, 97.2%), 99.2% (95% CI: 98.5%, 99.7%), and 97.5% (95% CI: 96.4%, 98.5%) respectively. The generalizability of the models was demonstrated through external validation with accuracies of 89.7 - 97.8%, 98.6 - 100%, and 87.8 - 98.6% for the same tasks. Conclusions: The developed models demonstrated high performance on both internal and external testing in identifying key aspects of a CT series.

Feasibility of periprocedural decision on the administration of intravenous contrast media in MRI for endometriosis

PurposeTo assess the feasibility of a periprocedural decision on the administration of intravenous contrast media in MRI for endometriosis and to evaluate the frequency and reasons of contrast administrations, the corresponding MRI diagnoses, and outcome. MethodsIn this retrospective, descriptive cross-sectional single-center study all patients were included, who received a pelvic MRI for evaluation of endometriosis between April 2021 and February 2023. Frequency and reasons of optional intravenous administration of contrast media, corresponding MRI diagnoses and clinical outcome data were noted after re-review of all images, review of radiology reports and review of patients’ medical records. The decision on the administration of intravenous contrast media had been made by experienced radiologists, depending on the findings of the non-contrast sequences and the presence of ancillary questions. Results303 consecutive patients (mean age, 33.4 years +/− 8.3 [standard deviation]) were evaluated. Periprocedural decision on the administration of intravenous contrast media had been made in all cases. For 219/303 (72.3%) patients, it was decided after review of the non-contrast sequences and exclusion of ancillary questions that contrast administration was not required. 84/303 (27.7%) patients received contrast media, and the most frequent reasons were indeterminate ovarian lesion (41/84 cases, 48.8%) or suspicion of pelvic venous congestion syndrome (26/84 cases, 31.0%). No relevant differences in patient outcomes could be noted (non-contrast/contrast MRI). ConclusionsA periprocedural decision on the administration of contrast media in MRI for endometriosis is feasible with little effort. It allows the administration of contrast media to be avoided in most cases. If the administration of contrast media is deemed necessary, repeat examinations can be avoided.

#5848 ROLE OF STATINS IN THE CONTRAST-INDUCED ACUTE KIDNEY INJURY PREVENTION AFTER COMPUTED TOMOGRAPHY WITH CONTRAST MEDIA

Abstract Background and Aims Contrast-induced acute kidney injury (CI-AKI) is a serious complication of the use of iodinated contrast media (CM). A number of researches have shown that statins have a protective role in the prevention of CI-AKI due to their pleiotropic effects. The aim of the study was to assess the influence of statins on the incidence of CI-AKI after intravenous CM administration. Method A randomized controlled open-label prospective study was conducted. Statin naive patients with cardiovascular diseases referred for contrast-enhanced computed tomography (CT) were included. Exclusion criteria were the use of statins and chronic kidney disease (CKD) stages 4-5. Acute kidney injury was defined as an increase in serum creatinine level by more than 44 μmol/L (0.5 mg/dL) or 25% from baseline within 48 hours after CM administration according to KDIGO guidelines. Glomerular filtration rate was calculated using the CKD-EPI formula. Overall, 181 patients were included in the study and divided into two groups. The first group (120 people) received high doses of atorvastatin (80mg or 40mg) 24 hours after and before the CM administration, while the second group (61 people), the control group, did not receive any statin therapy. Low-osmolar solutions in an amount of 100 ml were used. All patients were given intravenous hydration with saline before the study and 24 hours later. The statistical analysis was done using IBM SPSS Statistics v26.0. Results The patients in both groups did not significantly differ in age, BMI, coexisting conditions, and medications taken (Table 1). Both groups showed an increase in average creatinine levels after CT with intravenous CM administration, however, in the group of patients receiving high doses of statins, the average level increased less, p = 0.092 (Table 2). AKI developed in 12 individuals (6.7%), 9 of them were in the control group, and 3 were in the group receiving high doses of statins, p = 0.003. The chances of AKI development in the group receiving high doses of statins were 6.95 times lower compared to the control group (OR = 6.05, 95% CI: 1.7-21.5). Most of the patients had preserved kidney function and did not suffer from diabetes mellitus. There were statistically significantly more patients with preserved kidney function in the statin group, p = 0,007, OR: 2,374 (CI 95% 1,258 - 4,479), and fewer patients with CKD 3a stage, p = 0,05, OR: 0,406 (CI 95% 0,195 – 0,844). Conclusion Despite the presence of patients at risk, the incidence of CI-AKI was 6.7%, possibly due to additional prevention of this complication with intravenous saline before and after administration of the CM. In this trial, we observed that periprocedural administration of atorvastatin in high doses for a short duration, reduced the incidence of CI-AKI.

Structural changes in lung morphology detected by MRI after modulating therapy with elexacaftor/tezacaftor/ivacaftor in adolescent and adult patients with cystic fibrosis

IntroductionElexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) improves CFTR function in cystic fibrosis (CF) patients homozygous or heterozygous for F508del mutation. The aim of the study was to evaluate the response to ELX/TEZ/IVA treatment both clinically and morphologically in terms of bronchiectasis, bronchial wall thickening, mucus plugging, abscess and consolidations. MethodsWe retrospectively collected data from CF patients followed at Parma CF Centre (Italy) treated by ELX/TEZ/IVA between March and November 2021. Post-treatment changes in respiratory function, quality of life, sweat chloride concentration, body mass index, pulmonary exacerbations and lung structure by chest magnetic resonance imaging (MRI) were assessed. T2-and T1-weighted sequences were acquired with a 20 min-long scanning protocol on a 1.5T MRI scanner (Philips Ingenia) without administration of intravenous contrast media. Results19 patients (32.5 ± 10.2 years) were included in the study. After 6 months of treatment with ELX/TEZ/IVA, MRI showed significant improvements in the morphological score (p < 0.001), with a reduction in bronchial wall thickening (p < 0.001) and mucus plugging (p 0.01). Respiratory function showed significant improvement in predicted FEV1% (58.5 ± 17.5 vs 71.4 ± 20.1, p < 0.001), FVC% (79.0 ± 11.1 vs 88.3 ± 14.4, p < 0.001), FEV1/FVC (0.61 ± 0.16 vs 0.67 ± 0.15, <0.001) and LCI2.5% (17.8 ± 4.3 vs 15.8 ± 4.1 p < 0.005). Significant improvement was found in body mass index (20.6 ± 2.7 vs 21.9 ± 2.4, p < 0.001), pulmonary exacerbations (2.3 ± 1.3 vs 1.4 ± 1.3 p 0.018) and sweat chloride concentration (96.5 ± 36.6 vs 41.1 ± 16.9, p < 0.001). ConclusionsOur study confirms the efficacy of ELX/TEZ/IVA in CF patients not only from a clinical point of view but also in terms of morphological changes of the lungs.

Case 317

A 44-year-old previously healthy man with a 9-month history of progressive cognitive decline, depression, urinary incontinence, and inability to perform tasks of daily living presented to the emergency department with worsening cognitive and neuropsychiatric symptoms. He had become more distressed, and his family noticed him departing the house without closing doors, leaving water faucets running, and sending his children to school on Sundays. History taken from the patient's wife revealed that his brother had passed away in his late 30s after a slowly progressing functional and cognitive decline over the course of 5 years. No further detailed family history could be obtained. The review of systems was negative; he had no prior medical, psychiatric, or surgical history; and he denied any history of recent travel, camping, hiking, or vaccination. The patient was not taking any dietary supplements, nor was he taking any over-the-counter or prescription medication. Examination revealed vital signs were within normal limits. Neurocognitive assessment revealed a conscious, coherent, and alert patient with impaired memory and concentration. He showed poor attention, depressed mood, and restricted affect. He was unable to spell the word world forward, nor was he able to understand a request to spell it backward. The rest of the physical and neurologic examination revealed no abnormalities. Extensive laboratory work-up was conducted and included the following: toxicology screening; screening for HIV-1, HIV-2, and syphilis treponemal antibodies; COVID-19 polymerase chain reaction; and measurement of B1 and B12 levels. The results of screening were negative. Cerebrospinal fluid (CSF) assays, including CSF oligoclonal bands and CSF flow cytometry, revealed values within normal limits. CT of the brain without intravenous contrast material was performed in the emergency department to rule out acute intracranial abnormality (Fig 1). Multiplanar multisequence MRI of the brain without and with intravenous contrast material was ordered for further assessment (Figs 2-4). CT images of chest, abdomen, and pelvis were unremarkable (images not shown).

Efficacy and safety of N-acetylcysteine for preventing post-intravenous contrast acute kidney injury in patients with kidney impairment: a systematic review and meta-analysis.

N-Acetylcysteine (NAC) may confer protection against post-contrast acute kidney injury (PC-AKI), although evidence is sparse and conflicting. The objective was to analyse the evidence on the efficacy and safety of NAC vs no administration of NAC in preventing PC-AKI in patients with pre-existing kidney impairment undergoing a non-interventional radiological examination requiring intravenous (IV) contrast media (CM) administration. We carried out a systematic review including randomised controlled trials (RCTs) published in MEDLINE, EMBASE, and Clinicaltrials.gov up to May 2022. The primary outcome was PC-AKI. Secondary outcomes included the requirement of renal replacement therapy, all-cause mortality, serious adverse events, and length of hospital stay. We conducted the meta-analyses using the Mantel-Haenszel method and following a random-effects model. NAC was not associated with a significant reduction in PC-AKI (RR 0.47, 95%CI 0.20 to 1.11; 8 studies; 545 participants; I2: 56%; low certainty), all-cause mortality (RR 0.67, 95%CI 0.29 to 1.54; 2 studies; 129 participants; very low certainty), or length of hospital stay (mean difference 9.2days, 95%CI - 20.08 to 38.48; 1 study; 42 participants; very low certainty). The impact on other outcomes could not be determined. NAC may not reduce the risk of PC-AKI or all-cause mortality in people with kidney impairment who receive an IV CM prior to radiological imaging, although the certainty of the evidence is very low or low. Our review concludes that prophylactic administration of N-acetylcysteine may not significantly reduce the risk of acute kidney injury in patients with kidney impairment receiving an intravenous contrast media prior to non-interventional radiological imaging, which may support decision making in this common clinical scenario. • N-Acetylcysteine may not significantly reduce the risk of acute kidney injury in patients with kidney impairment receiving an intravenous contrast media prior to non-interventional radiological imaging. • All-cause mortality and length of hospital stay would not be decreased with the administration of N-Acetylcysteine in this setting.

Contrast-enhanced US with Perfluorobutane to Diagnose Small Lateral Cervical Lymph Node Metastases of Papillary Thyroid Carcinoma.

Background Although metastasis of lateral cervical lymph nodes (LNs) is common in papillary thyroid carcinoma (PTC), correctly diagnosing small metastatic LNs with US remains challenging. The use of contrast-enhanced US (CEUS), especially the postvascular phase of CEUS with perfluorobutane contrast material, might contribute to improved diagnosis of metastatic LNs in PTC. Purpose To assess the diagnostic value of the postvascular phase of CEUS with perfluorobutane in suspicious small lateral cervical LNs (short-axis diameter ≤8 mm) in patients with PTC. Materials and Methods This single-center study prospectively enrolled consecutive participants with confirmed PTC and suspicious LNs at US from October 2020 to October 2021. All participants underwent CEUS, 1 week before biopsy or surgery, with intravenous perfluorobutane contrast material to visualize the LNs in the vascular phase (5-60 seconds after injection) and postvascular phase (10-30 minutes after injection). The reference standard was cytologic and surgical histologic assessment of the LNs. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of sonographic features were calculated, and the diagnostic performance of US, CEUS, and the combination of postvascular phase and US features was assessed using multivariable logistic regression models. Results A total of 135 participants (median age, 36 years [IQR, 30-46 years]; 100 women) with 161 suspicious LNs at US were evaluated, including 67 metastatic and 94 benign LNs. The specificity of perfusion defect as a sonographic feature in the vascular phase reached 96% (90 of 94 LNs), and the negative predictive value of non-isoenhancement (ie, hypoenhancement, partial enhancement, and no enhancement) in the postvascular phase reached 100% (83 of 83 LNs). The area under the receiver operating characteristic curve (AUC) of the combination of postvascular phase and US features was 0.94 (95% CI: 0.89, 0.97), significantly higher than that of US features alone (AUC, 0.73; 95% CI: 0.65, 0.79; P < .001). Conclusion The postvascular phase of CEUS with perfluorobutane demonstrated excellent performance for diagnosing suspicious small lateral cervical LNs in participants with PTC. Published under a CC BY 4.0 license Supplemental material is available for this article. See also the editorial by Gunabushanam in this issue.

Strategies for improving colorectal cancer detection with routine computed tomography

To report the detection rate of colorectal tumors with computed tomography (CT) performed within 1year before diagnosis for indications other than colon abnormalities. Strategies to improve cancer detection are reported. Two board-certified, subspecialty-trained abdominal radiologists retrospectively reviewed patient health records and CT images with knowledge of tumor location/size. Patients were classified into 3 groups: prospective (colon abnormality suggesting neoplasm documented in radiologic report), retrospective (not documented in radiologic report but detected in our retrospective review of CT images), and undetected (neither prospectively nor retrospectively detected). Retrospective detection confidence and morphologic characteristics of each tumor were also recorded. Of 209 included patients, 106 (50.7%) had prospectively detected tumors, 66 (31.6%) had retrospectively detected tumors, and 37 (17.7%) had undetected tumors. Asymmetric bowel wall thickening and polypoid masses were present more often in the retrospective group than in the prospective group (27% vs. 10.5% and 26% vs. 17.1%, respectively). Tumors in the ascending colon were more likely to be detected retrospectively than prospectively (odds ratio, 2.75; 95% CI 1.07-7.08; P = 0.04). Undetected tumors were smaller on average (2.9cm) than prospective (6.0cm) and retrospective (4.9cm) tumors (P = 0.03). Detection confidence was lower for retrospectively detected tumors than for prospectively detected tumors (P = 0.03). Indications other than abdominal pain were most common for retrospectively detected tumors (P = 0.03). Use of intravenous contrast material was lowest in the undetected group (P = 0.003). The prospective group had more pericolonic abnormalities, regional/retroperitoneal lymph node involvement (P < 0.001), and distant metastases than did the retrospective group (P = 0.01). Half of all colorectal tumors were not detected prospectively. Radiologists should perform meticulous colon tracking regardless of the indication for CT. The right colon merits additional examination. Polypoid and asymmetric morphologic characteristics were most often overlooked, but these characteristics can be learned to improve detection.