To retrospectively determine the optimal noise indexes required to obtain diagnostically acceptable computed tomographic (CT) images of the abdomen and pelvis with z-axis modulation.
Ninety-five ...patients underwent 16-section multi-detector row CT of the abdomen and pelvis with z-axis modulation at noise indexes of 10.5, 11.0, 11.5, and 12.0 HU with 10-380 mA. Subsequently, 58 patients were scanned at noise indexes of 12.5 and 15.0 HU with 75-380 mA. The weights of all subjects were recorded, and transverse and anteroposterior diameters were measured. The CT images were evaluated for abnormalities and graded for image quality in terms of noise and diagnostic acceptability by using a five-point scale. Objective noise in the liver parenchyma was measured, and the tube current was recorded at each section in all 153 patients. Statistical analyses were performed to determine the appropriate noise index and to assess the effect of patient weight and abdominal diameters on image noise and diagnostic acceptability at different noise indexes. Tube current-time products (in milliampere seconds) at various noise indexes were compared with those at CT previously performed without z-axis modulation.
No significant difference in subjective image noise or diagnostic acceptability was found at noise indexes of 10.5-15.0 HU (P =.14), and objective noise was significantly inferior only at a noise index of 15.0 HU (P =.009). Compared with CT scanning at a 10.5-HU noise index, CT scanning at 12.5- and 15.0-HU noise indexes yielded, respectively, 10.0% and 41.3% reductions in radiation exposure. Patient weight and abdominal diameters affected subjective image quality.
Use of a 15.0-HU noise index at 75-380 mA results in acceptable subjective image noise and diagnostic acceptability but significantly greater objective image noise at routine abdominal-pelvic CT. For greater image quality demands, a noise index of 12.5 HU results in acceptable image quality and a 19.6% reduction in radiation exposure.
Background and aims: Computed tomography (CT), often more accessible than magnetic resonance imaging (MRI), remains widely used though radiation exposure is an obvious disadvantage. We previously ...showed that modern CT technology can achieve over 70% reduction in radiation-dose without loss of accuracy. Here, we compare low- versus conventional-dose CT in patients with known Crohn's disease to assess clinical confidence and accuracy of the low-dose procedure in the semi-acute setting.
Methods: A comparative study of low-dose CT with full iterative reconstruction (IR) versus conventional-dose CT was conducted in 50 consecutive outpatients with Crohn's disease. Clinicians were provided with the low-dose images and reports, whereas conventional-dose images were reviewed after 4 weeks.
Results: The clinical question was adequately addressed with low-dose IR imaging in all cases. Complications of Crohn's were detected in 37/50 (74%) with no disagreement between low- and conventional-dose imaging. The effective radiation dose reduction was 76.5% (low-dose mean 2.15 mSv versus conventional-dose CT 6.99 mSv).
Conclusion: Low-dose IR CT is safe and accurate for evaluating distribution and complications of known Crohn's disease in the outpatient setting. We propose that low-dose radiation imaging should be adopted as standard-of-care for the evaluation of Crohn's disease and an acceptable alternative to MR particularly in the acute setting. ClinicalTrials.gov: NCT03140306.
Objectives
Performance of a modified abdominopelvic CT protocol reconstructed using full iterative reconstruction (IR) was assessed for imaging patients presenting with acute abdominal symptoms.
...Materials and methods
Fifty-seven patients (17 male, 40 female; mean age of 56.5 ± 8 years) were prospectively studied. Low-dose (LD) and conventional-dose (CD) CTs were contemporaneously acquired between November 2015 and March 2016. The LD and CD protocols imparted radiation exposures approximating 10–20% and 80–90% those of routine abdominopelvic CT, respectively. The LD images were reconstructed with model-based iterative reconstruction (MBIR), and CD images with hybrid IR (40% adaptive statistical iterative reconstruction (ASIR)). Image quality was assessed quantitatively and qualitatively. Independent clinical interpretations were performed with a 6-week delay between reviews.
Results
A 74.7% mean radiation dose reduction was achieved: LD effective dose (ED) 2.38 ± 1.78 mSv (size-specific dose estimate (SSDE) 3.77 ± 1.97 mGy); CD ED 7.04 ± 4.89 mSv (SSDE 10.74 ± 5.5 mGy). LD-MBIR images had significantly lower objective and subjective image noise compared with CD-ASIR (
p
< 0.0001). Noise reduction for LD-MBIR studies was greater for patients with BMI < 25 kg/m
2
than those with BMI ≥ 25 kg/m
2
(5.36 ± 3.2 Hounsfield units (HU) vs. 4.05 ± 3.1 HU,
p
< 0.0001). CD-ASIR studies had significantly better contrast resolution, and diagnostic acceptability (
p
< 0.0001 for all). LD-MBIR studies had significantly lower streak artifact (
p
< 0.0001). There was no difference in sensitivity for primary findings between the low-dose and conventional protocols with the exception of one case of enteritis.
Conclusions
Low-dose abdominopelvic CT performed with MBIR is a feasible radiation dose reduction strategy for imaging patients presenting with acute abdominal pain.
Medical imaging involving the use of ionizing radiation has brought enormous benefits to society and patients. In the past several decades, exposure to medical radiation has increased markedly, ...driven primarily by the use of computed tomography. Ionizing radiation has been linked to carcinogenesis. Whether low-dose medical radiation exposure will result in the development of malignancy is uncertain. This paper reviews the current evidence for such risk, and aims to inform the gastroenterologist of dosages of radiation associated with commonly ordered procedures and diagnostic tests in clinical practice. The use of medical radiation must always be justified and must enable patients to be exposed at the lowest reasonable dose. Recommendations provided herein for minimizing radiation exposure are based on currently available evidence and Working Party expert consensus.
Immune checkpoint inhibitors (ICI) are increasingly being used to treat numerous cancer types. Together with improved recognition of toxicities, this has led to more frequent identification of rare ...immune-related adverse events (irAE), for which specific treatment strategies are needed. Neutropenia is a rare hematological irAE that has a potential for a high mortality rate because of its associated risk of sepsis. Prompt recognition and timely treatment of this life-threatening irAE are therefore critical to the outcome of patients with immune-related neutropenia.
This multicenter international retrospective study was conducted at 17 melanoma centers to evaluate the clinical characteristics, diagnostics, treatment, and outcomes of melanoma patients with grade 4 neutropenia (<500 neutrophils/µl blood) treated with ICI between 2014 and 2020. Some of these patients received metamizole in addition to ICI (ICI+/met+). Bone marrow biopsies (BMB) of these patients were compared to BMB from non-ICI treated patients with metamizole-induced grade 4 neutropenia (ICI-/met+).
In total, 10 patients (median age at neutropenia onset: 66 years; seven men) with neutropenia were identified, equating to an incidence of 0.14%. Median onset of neutropenia was 6.4 weeks after starting ICI (range 1.4-49.1 weeks). Six patients showed inflammatory symptoms, including fever (n=3), erysipelas (n=1), pharyngeal abscess (n=1), and mucositis (n=1). Neutropenia was diagnosed in all patients by a differential blood count and additionally performed procedures including BMB (n=5). Nine of 10 patients received granulocyte colony-stimulating factors (G-CSF) to treat their grade 4 neutropenia. Four patients received systemic steroids (including two in combination with G-CSF, and one in combination with G-CSF and additional ciclosporin A). Four patients were treated with one or more antibiotic treatment lines, two with antimycotic treatment, and one with additional antiviral therapy. Five patients received metamizole concomitantly with ICI. One fatal outcome was reported. BMB indicated a numerically lower CD4+ to CD8+ T cells ratio in patients with irNeutropenia than in those with metamizole-induced neutropenia.
Grade 4 neutropenia is a rare but potentially life-threatening side effect of ICI treatment. Most cases were sufficiently managed using G-CSF; however, adequate empiric antibiotic, antiviral, and antimycotic treatments should be administered if neutropenic infections are suspected. Immunosuppression using corticosteroids may be considered after other causes of neutropenia have been excluded.
Cadaveric material has long been used to teach anatomy and more recently to train students in clinical skills. The aim of this study was to develop a systematic approach to compare the impact of four ...embalming solutions on the tissues of human cadavers. To this end, a formalin‐based solution, Thiel, Genelyn and Imperial College London soft‐preservation (ICL‐SP) solution were compared. The effect of these chemicals on the properties of the tissue was assessed by measuring the range of motion (ROM) of joints and measuring the dimensions of different structures on computed tomography (CT) images before and after embalming. The mean changes in the ratio (angle to ROM) differed statistically between embalming methods (Welch Statistic 3,1.672 = 67.213, p = 0.026). Thiel embalmed cadavers showed an increase in range of motion while ICL‐SP cadavers remained relatively the same. Genelyn and formalin embalmed cadavers registered a notable decrease in range of motion. Furthermore, investigation into the impact of the embalming chemicals on the dimensions of internal organs and vessels revealed that Thiel embalming technique leads to a decrease in the dimension of the cardiovascular system alone while formalin‐based solutions maintain the shape of the organs and vessels investigated. Our findings suggest that the joints of cadavers’ embalmed using ICL‐SP technique may faithfully mimic that of unembalmed cadavers and that formalin is necessary to retain shape and size of the organs and vessels investigated in this study. Despite this, a study with larger numbers of cadavers is required to confirm these findings.
To critically evaluate the current literature in an effort to establish the current role of radiologic imaging (computed tomography, magnetic resonance imaging, ultrasonography US, fluoroscopy, ...conventional film radiography) in irritable bowel syndrome (IBS).
The term "irritable bowel syndrome" was used to search Clinical Evidence, UpToDate, Cochrane Library, TRIP, and National Institute for Health and Clinical Excellence databases and the American College of Physicians Journal Club and Evidence-Based Medicine online. PubMed was searched by using medical subject headings ("irritable bowel syndrome;" "colonic diseases, functional;" "diagnosis;" "colonography;" "computed tomographic (CT)") and the dates January 1, 1985 to July 1, 2010. Appraisal was independently performed by two reviewers who followed the Oxford Centre for Evidence Based Medicine practice criteria.
No systematic review (SR) specifically examined radiologic imaging in IBS; however, in the secondary literature, five relevant SRs or guidelines partially addressed this topic. A PubMed search identified 1451 articles, 111 of which at least partially addressed radiologic imaging. Of these, seven valid articles (two SRs and five primary research articles) were identified. The five primary research articles examined either colonic investigations (colonoscopy and barium enema examination) (n=5) or US (n=2) or both (n=2). Structural disease found infrequently in patients with IBS-type symptoms included diverticulosis, colorectal cancer, celiac disease, inflammatory bowel disease, and ovarian cancer. The incidence of structural disease in patients with concerning symptoms was low.
Although widely used, there is a surprising paucity of evidence guiding radiologic imaging in IBS. Radiologic imaging may not be required in patients with IBS without potentially concerning symptoms but should be considered where such symptoms exist, and choice of imaging study should be influenced by predominant symptoms. Definitive recommendations must await further research.
Background
Diagnosing the aetiology of interstitial lung disease (ILD) may require histology via a surgical lung biopsy (SLB). SLB is associated with significant complications. Transbronchial lung ...cryobiopsy (TBLC) can provide large, adequate biopsies with fewer complications offering a potential alternative to SLB.
Aims
This study evaluated the safety, diagnostic yield and impact of TBLC on diagnostic certainty in the multidisciplinary diagnosis (MDD) of ILD within routine clinical practice.
Methods
A retrospective study of all TBLC performed in a tertiary institute from March 2014 to December 2016 was performed. Procedures were performed using a flexible bronchoscope and cryoprobe without fluoroscopic guidance.
Results
One hundred procedures were performed on 85 patients. A total of 272 cryobiopsies were obtained with a mean biopsy diameter of 5.9 ± 3.2 mm. Ninety-seven percent contained alveolated lung tissue. Diagnosis based against MDD gold standard was confirmed using TBLC in 67.1% of patients and in 72/100 procedures. Three patients proceeded to SLB. The addition of histological information changed the clinic-radiological diagnosis in twelve patients. The most common diagnosis based on clinical-radiologic-pathologic correlation at MDD was idiopathic pulmonary fibrosis (IPF) (51.2%) and hypersensitivity pneumonitis (15.9%). Moderate bleeding occurred in 18% of cases and five patients (5%) developed pneumothorax requiring intervention. Eleven patients required admission, with a mean length of stay of 1.3 ± 0.9 days.
Conclusion
TBLC aids the diagnosis of ILD in the appropriate patient and may be an acceptable alternative to SLB with fewer complications. Further work on standardizing the procedure is required.
Imaging of biliary tract disease O'Connor, Owen J; O'Neill, Siobhan; Maher, Michael M
American journal of roentgenology (1976)
197, Številka:
4
Journal Article
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