Objective
To evaluate the ability of pediatric patients with known or suspected inflammatory bowel disease to ingest a new oral distending agent at CT or MR enterography (CTE/MRE), and to determine ...the impact on small bowel (SB) distension and diagnostic confidence.
Materials and methods
The study design is that of retrospective review of pediatric patients who underwent CTE or MRE from January 2014 to June 2016. Patients ingested low-concentration barium suspension or flavored beverage containing sorbitol and mannitol. The need for nasogastric tube (NGT) administration, amount ingested, emesis, distal extent of contrast, SB distension, terminal ileum (TI) transverse dimension, and diagnostic confidence in TI disease were assessed. Three radiologists each blindly reviewed a subset of the studies.
Results
Of the total 591 scans in 504 patients, 316 scans used low-concentration barium suspension and 275 scans flavored beverage. Nearly all consumed the entire amount (97% vs. 96%). Low-concentration barium suspension exams required NGT more often (7% 23/316 vs. 1% 3/275;
p
< 0.0003), and tended to have more emesis (3% 9/316 vs. 1% 3/275;
p
= 0.13). Diagnostic confidence score was nearly identical (
p
= 0.94). Qualitative and quantitative analyses showed no difference in SB distension, except for distension of mid-ileum (flavored beverage > low-concentration barium suspension;
p
= 0.02). Flavored beverage exams demonstrated a slight increase in distal extent of luminal distension (
p
= 0.02).
Conclusions
A new flavored beverage distends small bowel as well as low-concentration barium suspension, with decreased requirement for NGT insertion and improved distal extent of luminal distension, and without any decrease in diagnostic confidence in the presence or the absence of TI disease.
Purpose
Prior iterative reconstruction (PIR) spatially registers CT image data from multiple phases of enhancement to reduce image noise. We evaluated PIR in contrast-enhanced multiphase liver CT.
...Methods
Patients with archived projection CT data with proven malignant or benign liver lesions, or without lesions, by reference criteria were included. Lower-dose PIR images were reconstructed using validated noise insertion from multiphase CT exams (50% dose in 2 phases, 25% dose in 1 phase). The phase of enhancement most relevant to the diagnostic task was selected for evaluation. Four radiologists reviewed routine-dose and lower-dose PIR images, circumscribing liver lesions and rating confidence for malignancy (0 to 100) and image quality. JAFROC Figures of Merit (FOM) were calculated.
Results
31 patients had 60 liver lesions (28 primary hepatic malignancies, 6 hepatic metastases, 26 benign lesions). Pooled JAFROC FOM for malignancy for routine-dose CT was 0.615 (95% CI 0.464, 0.767) compared to 0.662 for PIR (95% CI 0.527, 0.797). The estimated FOM difference between the routine-dose and lower-dose PIR images was + 0.047 (95% CI − 0.023, + 0.116). Pooled sensitivity/specificity for routine-dose images was 70%/68% compared to 73%/66% for lower-dose PIR. Lower-dose PIR had lower diagnostic image quality (mean 3.8 vs. 4.2,
p
= 0.0009) and sharpness (mean 2.3 vs. 2.0,
p
= 0.0071).
Conclusions
PIR is a promising method to reduce radiation dose for multiphase abdominal CT, preserving observer performance despite small reductions in image quality. Further work is warranted.
Toxicity testing in AS52 cells (24-hr exposures) gave LC50values of 2 to 130 μg Ni/ml for particulate nickel compounds and 45 to 60 μg Ni/ml for water-soluble salts ( NiCl2, NiSO4, Ni( CH3COO)2). The ...Ni( OH)2, NiCO3, and sulfides ( Ni3S2, Ni7S6, "amorphous NiS") exhibited similar toxicities ( LC50's of 2 to 8 μg Ni/ml), while three nickel oxides were more variable and less toxic ( LC50's of 18 to 130 μg Ni/ml). Most compounds displayed nuclear to cytoplasmic nickel ratios of ≈ 1:1.5 to 1:5 (except ≈ 1:20 for nickel salts). At the LC50's, a 75-fold range in exposure levels occurred compared to a 10-fold range in cytoplasmic and nuclear nickel concentrations, Ni. Cellular nickel distribution indicated three groupings: inert compounds (green NiO, lithium nickel oxide, relatively low nuclear and cytosolic Ni); water-soluble salts (very low nuclear Ni; high cytosolic Ni), and slightly soluble compounds (relatively high cytosolic and nuclear Ni). Nickel compounds are considered to be only weak or equivocal mutagens. In this study, a low but significant increase in mutation rate at the gpt locus was shown. Although the results would not be sufficient to deem nickel compounds mutagenic by traditional criteria, characterization by PCR analysis indicated that the spontaneous and nickel-induced mutants exhibited different and compound-specific mutational spectra (thus confirming nickel compound involvement). The results reported illustrate some of the methodologic problems involved in testing "weak" mutagens and indicate that alternative approaches may be necessary in classifying the mutagenicity of nickel and other compounds.
To describe visualization of gastrointestinal neural ganglia by endoscopic ultrasound (EUS).
We retrospectively identified patients in whom neural ganglia were visualized during EUS and the diagnosis ...of ganglion confirmed by EUS guided fine needle aspiration (FNA) cytology.
Ten patients were identified. Celiac ganglia were visualized in nine, and a perirectal ganglion was visualized in one. Ganglia appeared as discrete hypoechoic structures, often with associated hypoechoic threads that may represent neural rami. Aspiration of ganglia yielded scant material and caused transient pain. Ganglia were best visualized with linear array echoendoscopes. Celiac ganglia (but not the perirectal ganglion) were retrospectively identified on computed tomography scans.
Gastrointestinal neural ganglia can be imaged by EUS and their identity confirmed by EUS FNA.
PURPOSE:Hip prosthesis is one of the most common types of metal implants and can cause significant artifacts in computed tomography (CT) examinations. The purpose of this work was to develop a ...projection-based method for reducing metal artifacts caused by hip prostheses in multislice helical CT.
METHOD AND MATERIALS:The proposed method is based on a novel concept, reformatted projection, which is formed by combining the projection data at the same view angle over the full longitudinal scan range. Detection and segmentation of the metal were performed on each reformatted projection image. Two dimensional interpolation based on Delaunay triangulation was used to fill voids left after removal of the metal in the reformatted projection. The corrected data were then reconstructed using a commercially available algorithm. The main advantage of this method is that both the detection of the metal objects and the interpolations are performed on complete reformatted projections with the entire metal region present, which is particularly useful for long hip prostheses. Twenty clinical abdominal/pelvis exams with hip prostheses were corrected and clinically evaluated.
RESULTS:The overall image quality and the conspicuity in some critical organs were significantly improved compared with the uncorrected imagesoverall quality (P = 0.0024); bladder base (P = 0.0027), and rectum (P = 0.0078). The average noise level in the bladder base was reduced from 86.7 HU to 36.2 HU. In 17 of 20 cases, the radiologists preferred either coronal (13) or axial (4) views of the corrected images.
CONCLUSIONS:A novel method for reducing metal artifact in multislice helical CT was developed. Initial clinical results showed that the proposed method can effectively reduce the artifacts caused by metal implants for the cases of unilateral and bilateral hip prothesis.
A quantitative real-time polymerase chain reaction (PCR) detection method specific for Listeria monocytogenes was developed, and studies involving pure culture showed that the response of the assay ...was linear over 7 log10 (log) cycles. The method was then applied to the detection of L. monocytogenes artificially inoculated onto cabbage, a vegetable chosen because it is a major component of coleslaw, which has been associated with an outbreak of listeriosis. After being allowed to attach to the food, cells were washed from the cabbage leaf surface and recovered by centrifugation. The DNA was purified by an organic solvent extraction technique and analyzed by real-time PCR. In this matrix, the method again produced a linear response over 7 log cycles from 1.4 x 10(2) to 1.4 x 10(9) CFU of L. monocytogenes in 25 g of cabbage, and analysis of the reproducibility of the system showed that log differences in L. monocytogenes numbers added to cabbage could be reliably distinguished. The system allowed quantitative results to be obtained within 8 h and was relatively inexpensive, showing good potential for routine analytical use.
Interactive fast spin-echo imaging Busse, Reed F.; Riederer, Stephen J.; Fletcher, Joel G. ...
Magnetic resonance in medicine,
September 2000, Letnik:
44, Številka:
3
Journal Article
Our purpose was to determine the prevalence of polyps that are invisible on CT colonography (CTC) in a population previously screened for colorectal neoplasms. Differences in the prevalence of occult ...polyps in various populations might help explain the discordant reported sensitivities for polyp detection in published reports of CTC.
Seventy-five consecutive patients who had been previously screened for polyps underwent same-day colonoscopy and CTC. Many of the patients had personal histories of previous polypectomies and were undergoing surveillance colonoscopy. The scans were interpreted prospectively by an experienced radiologist. Polyps missed prospectively on CTC were analyzed retrospectively by three experienced radiologists and categorized as perception errors (visible in retrospect), technical errors (e.g., obscured by feces or fluid), or occult (invisible).
Thirty polyps 5 mm or larger were found at colonoscopy, 18 of which were missed prospectively on CTC. Of the 18 missed polyps, 12 could not be identified in retrospect, even though they were located in clean, dry, well-distended colonic segments. These were classified as occult. Ten of the 12 occult polyps showed flat morphology on review of colonoscopy video recordings. Of the remaining six missed polyps, two were classified as perception errors, two as technical errors, and two as a combination of technical and perception error.
In this population, colonographically occult polyps were common and accounted for more detection failures than perception errors and technical errors combined. The high prevalence of occult polyps may be explained by the fact that previous screening may have led to removal of easy-to-see polyps, creating a study population with a higher percentage of hard-to-see polyps.
Background:
Computed tomographic enterography (CTE) has been shown to have a high sensitivity and specificity for active small bowel inflammation. There are only sparse data on the effect of CTE ...results on Crohn's disease (CD) patient care.
Methods:
We prospectively assessed 273 patients with established or suspected CD undergoing a clinically indicated CTE. Providers were asked to complete pre‐ and postimaging questionnaires regarding proposed clinical management plans and physician level of confidence (LOC) for the presence or absence of active small bowel disease, fistula(s), abscess(es), or stricturing disease. Correlative clinical, serologic, and histologic data were recorded. Following revelation of CTE results, providers were questioned if CTE altered their management plans, and whether LOC changes were due to CTE findings (on a 5‐point scale).
Results:
CTE altered management plans in 139 cases (51%). CTE changed management in 70 (48%) of those with established disease, prompting medication changes in 35 (24%). Management changes were made post‐CTE in 69 (54%) of those with suspected CD, predominantly due to excluding CD (36%). CTE‐perceived changes in management were independent of clinical, serologic, and histologic findings (P < 0.0001). Clinically meaningful LOC changes (2 or more points) were observed in 212 (78%).
Conclusions:
CTE is a clinically useful examination, altering management plans in nearly half of patients with CD, while increasing physician LOC for the detection of small bowel inflammation and penetrating disease. These findings further support the use of CTE in CD management algorithms. (Inflamm Bowel Dis 2011;)
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