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With optimized technique, the water-soluble contrast challenge is effective at triaging patients for operative vs non-operative management of suspected small bowel obstruction. Standardized study structure and interpretation guidelines aid in clinical efficacy and ease of use. Many tips and tricks exist regarding technique and interpretation, and their understanding may assist the interpreting radiologist. In the future, a CT-based water-soluble contrast challenge, utilizing oral contrast given as part of the initial CT examination, might allow for a more streamlined algorithm and provide more rapid results.

Percutaneous ultrasound-guided biopsies have become the standard of practice for tissue diagnosis in the abdomen and pelvis for many sites including liver, kidney, abdominal wall, and peripheral nodal stations. Additional targets may appear difficult or impossible to safely biopsy by ultrasound due to interposed bowel loops/vasculature, deep positioning, association with the bowel, or concern for poor visibility; however, by optimizing technique, it is often possible to safely and efficiently use real-time ultrasound guidance for sampling targets that normally would be considered only appropriate for CT guided or surgical/endoscopic biopsy.

The purpose of this study was to assess whether a specific liver attenuation threshold for unenhanced CT allows both sensitive opportunistic detection of unsuspected hereditary hemochromatosis and low overall screening test-positive rates.We used a standard ROI placement method on unenhanced CT studies of 3357 consecutive adults (mean age, 57.0 years) with no symptoms of liver disease who underwent colorectal screening. Hepatic attenuation (in HU) was measured to assess test-positive rates at various liver attenuation thresholds. To assess sensitivity, unenhanced hepatic CT attenuation was also measured in 12 patients with hereditary hemochromatosis (mean age, 48.3 years), who were homozygous for the HFE C282Y mutation. All scans were obtained at 120 kV. Serum ferritin levels were recorded for the hereditary hemochromatosis cohort.Mean liver attenuation ± SD among screened adults was 59.4 ± 12.7 HU, compared with 78.7 ± 13.1 HU (range, 59-105 HU) in the hereditary hemochromatosis cohort (p0.001). Screening test-positive rates were 30.6% (n = 1028) at 65 HU, 8.2% (n = 275) at 70 HU, 1.2% (n = 39) at 75 HU, and 0.2% (n = 7) at 80 HU. Corresponding sensitivities for hereditary hemochromatosis at these thresholds were 83.3% (10/12) at 65, 70, and 75 HU; and 50.0% (6/12) at 80 HU. Serum ferritin levels were elevated in all patients with hereditary hemochromatosis (mean, 1678 ng/mL; range, 477-3991 ng/mL).An unenhanced CT liver attenuation threshold of 75 HU was sensitive (83.3%) for hereditary hemochromatosis while maintaining an acceptably low screening test-positive rate (1.2%). An unexplained liver attenuation of 75 HU or more on unenhanced CT should trigger appropriate laboratory investigation for iron overload; early intervention with phlebotomy can limit or prevent organ damage in patients with hemochromatosis.

36 Background: Interest has arisen in the use of prostate specific membrane antigen (PSMA) PET/CT imaging to detect prostate cancer at metastatic sites using different tracers. Here, we examined the ability of 18F-DCFPyL (DCFPyL) PSMA-based PET imaging to detect nodal disease in comparison to conventional imaging in a cohort of men with locally advanced or oligometastatic prostate cancer (PC). Methods: UW17009 is an IRB-approved open-label, single-arm trial that enrolled 26 patients with newly diagnosed advanced PC. Patients received androgen deprivation therapy and docetaxel for 3 months followed by radical prostatectomy (RP) and pelvic lymph node dissection (PLND). Exploratory interventions include PSMA PET/CT and MRI imaging as a method for determining treatment response and heterogeneity in primary PC and metastatic lesions performed before and after chemohormonal therapy. Prior to randomization, patients received DCFPyL PET/CT and PET/MR imaging as well as CTs and Bone Scans. A mean dose of 7.86 mCi DCFPyL was administered. Whole-body PET/CT images were acquired starting at approximately 60 minutes after radiotracer injection followed by dedicated pelvic PET/MR and whole-body PET/MR. PET imaging findings were compared to conventional dedicated CT imaging and were correlated to the results of final pathologic examination of each pelvic nodal dissection. Results: 26 patients underwent conventional and exploratory imaging with subsequent neoadjuvant treatment, RP and PLND. The mean diagnostic PSA was 32.1 ng/dl and 88.5% had Gleason 9 PCa. Using conventional imaging, pelvic nodal disease was identified in 6/26 patients. Pelvic lymph node uptake was identified in 12/26 patients using DCFPyL-based PSMA PET. Initial correlation of the pathologic specimens with pretreatment PSMA PET imaging revealed pelvic nodal metastatic PC in 10/12(83%) patients. On a per-lymph node packet basis (6 per patient), there were 156 evaluable regions, including 65 from patients with positive nodes. PSMA detected 14 packets that were positive for PC and 102 packets that were negative on imaging and final pathology. PC was missed in 5 packets. The mean tumor size in the missed nodes was 2.3 mm(range 1-4 mm). Calculated sensitivity was 73.7%(95% CI [48.8, 90.8]), 85.7 % specificity(95% CI[78.1, 91.4]), and 95.3 % negative predictive value(95% CI[90.5, 97.7]). Conclusions: In comparison to conventional imaging, in this cohort, DCFPyL PSMA-based PET imaging identified nodal positive disease at twice the rate and when evaluating on a per-packet basis, there was high negative predictive value. Ongoing analysis of post-chemohormonal therapy PET imaging may provide more information regarding tumor response in this cohort.

Objective To evaluate diffusion kurtosis imaging (DKI) and magnetisation transfer imaging (MTI) compared to standard MRI for prostate cancer assessment in a re-biopsy population. Methods Thirty-patients were imaged at 3 T including DKI (Kapp and Dapp) with b-values 150/450/800/1150/1500 s/mm2 and MTI performed with and without MT saturation. Patients underwent transperineal biopsy based on prospectively defined MRI targets. Receiver-operating characteristic (ROC) analyses assessed the parameters and Wilcoxon-signed ranked test assessed relationships between metrics. Results Twenty patients had ≥ 1 core positive for cancer in a total of 26 MRI targets (Gleason 3+3 in 8, 3+4 in 12, ≥ 4+3 in 6): 13 peripheral (PZ) and 13 transition zone (TZ). The apparent diffusion coefficient (ADC) and Dapp were significantly lower and the Kapp and MT ratio (MTR) significantly higher in tumour versus benign tissue (all p ≤ 0.005); ROC values 0.767-1.000. Normal TZ had: lower ADC and Dapp and higher Kapp and MTR compared to normal PZ. MTR showed a moderate correlation to Kapp (r = 0.570) and Dapp (r = -0.537) in normal tissue but a poor correlation in tumours. No parameter separated low-grade (Gleason 3+3) from high-grade (≥ 3+4) disease for either PZ (p = 0.414-0.825) or TZ (p = 0.148-0.825). Conclusion ADC, Dapp, Kapp and MTR all distinguished benign tissue from tumour, but none reliably differentiated low- from high-grade disease. Key Points • MTR was significantly higher in PZ and TZ tumours versus normal tissue • K app was significantly lower and D app higher for PZ and TZ tumours • There was no incremental value for DKI/MTI over mono-exponential ADC parameters • No parameter could consistently differentiate low-grade (Gleason 3+3) from high-grade (≥ 3+4) disease • Divergent MTR/DKI values in TZ tumours suggests they offer different functional information Electronic supplementary material The online version of this article (10.1007/s00330-017-5169-1) contains supplementary material, which is available to authorized users.

Objectives To measure the performance characteristics of combined T2-weighted (T2W) and diffusion-weighted (DW) magnetic resonance imaging (MRI) suspicion scoring prior to MR-transrectal ultrasound (TRUS) fusion template transperineal (TTP) re-biopsy.

OBJECTIVE: The purpose of this study was to investigate the ability of the apparent diffusion coefficient (ADC) ratio of tumor to normal prostate tissue to overcome inherent variability based on choice of b values, with whole-mount histopathologic analysis as the reference standard for tumor identification. MATERIALS AND METHODS: Thirty-nine patients with prostate cancer underwent 3-T MRI, including DWI with b values of 0, 150, 750, and 1000 s/mm(2). ADC maps were derived from four b value combinations. Histologically derived ROIs were defined for prostate tumor and benign prostate tissue to generate a ratio. The concordance correlation coefficient was used to evaluate agreement and reproducibility at different b values. Bland-Altman plots were used to evaluate the pattern of relative measurement difference between b value combinations. The relationship between ADC values and Gleason score was tested by Spearman rank correlation. RESULTS: ADC values varied depending on the b value combination selected. The concordance correlation coefficient was higher for ADC ratios (0.883; 95% CI, 0.816-0.927) compared with absolute ADC values for normal tissue (0.873; 95% CI, 0.799-0.921) and tumor (0.792; 95% CI, 0.688-0.864). The ADC ratio concordance correlation coefficient for transition zone tumors was considerably higher than that for the peripheral zone in all cases. Bland-Altman analysis showed higher variation for ADC maps incorporating a b value of zero for both ratio and absolute values. There was a stronger inverse relationship to Gleason score for ADC ratios (rho, -0.354 to -0.456) compared with absolute ADC values (rho, -0.117 to -0.379). CONCLUSION: The use of a simple ratio of prostate tumor ADC to normal tissue ADC improved the concordance between different b value combinations and could provide a more robust means of assessing restricted diffusion in the prostate.

Elderly adults are at increased risk for complications related to both delayed diagnosis of appendicitis and to unnecessary appendectomy. We assessed the diagnostic performance of computed tomography (CT) in a consecutive elderly cohort with clinically suspected appendicitis. CT findings and clinical outcomes were analyzed for 262 consecutive adult patients age 65 and older (mean 75.6 ± 7.5 years; range 65-94; M/F 111:151) referred for clinically suspected appendicitis at a single medical center between January 2000 and December 2009. The overall prevalence of proven acute appendicitis in this elderly cohort with clinically suspected appendicitis was 16.8% (44/262). CT sensitivity, specificity, PPV, and NPV for acute appendicitis were 100% (44/44), 99.1% (216/218), 95.7% (44/46), and 100.0% (216/216), respectively. The negative appendectomy rate was 2.3% (1/43). The perforation rate was 40.9% (18/44). There were no false-negative and two false-positive CT interpretations. All patients with appendicitis suspected on CT were hospitalized (44/44), with an average stay of 5.7 ± 3.2 days, and 93.5% (43/46) underwent appendectomy. Overall surgical complication rate was 34.9% (15/43). Compared with younger adults over the same period, elderly patients had higher rates of perforation and surgical complications, and longer hospital stays (p

The purpose of this study was to prospectively evaluate the value of diffusion-weighted MRI (DWI) for the assessment of extracapsular extension (ECE) in patients with prostate cancer.Between November 2010 and April 2012, 40 patients with intermediate- to high-risk prostate cancer were prospectively recruited. MR images were obtained at 3 T with a phased-array coil. Two independent readers scored the T2-weighted images alone and then in combination with DW images. ROIs were drawn on the apparent diffusion coefficient (ADC) maps, and histogram-derived values were calculated. Whole-mount histopathologic examination was the standard of reference. Reader performance was analyzed, and differences in patient characteristics and histogram-based ADC values, according to ECE status, were evaluated.ECE was present in 23 of 40 (58%) patients and 23 of 43 (53%) tumors. The sensitivity for side-specific ECE detection significantly increased, from 0.22 to 0.44 for reader 1 and 0.33 to 0.82 for reader 2 (both p0.05) without a significant change in specificity for either reader with the addition of DWI and ADC mapping. The positive and negative predictive values for both readers also increased. The ADC parameters of median and 10th and 25th centiles showed a statistically significant difference between tumors with and those without ECE (p0.05).The addition of DWI and ADC mapping to T2-weighted MRI improved the accuracy of preoperative detection of ECE. Median and 10th and 25th centile ADC values were significantly associated with the presence of ECE and may be useful in the pretreatment assessment of patients with prostate cancer.

To determine if appendiceal lengths differ between adults with acute appendicitis and asymptomatic controls.In vivo appendiceal length at computed tomography (CT) in 321 adults with surgically proven appendicitis was compared with that in 321 consecutive asymptomatic adult controls. CT length was derived using curved multiplanar reformats along the long axis. Gross pathological length provided external validation for appendectomy cases.Appendiceal length at CT correlated well with appendicitis specimens (mean length, 6.8 cm vs 6.6 cm; 79 % within 1.5 cm). For asymptomatic controls, mean CT appendiceal length was 7.9 cm, longer in men (8.4 ± 3.8 vs 7.4 ± 3.1 cm; P = 0.02), matching closely historical normative post-mortem data. The mean and standard deviation of appendiceal length at CT were significantly greater among negative controls than in the positive appendicitis group (7.9 ± 3.5 vs 6.8 ± 1.9 cm; P = 0.03). Of appendicitis cases, 90 % (288/321) fell within the range 4.0-10.0 cm, compared with 59 % (189/321) of negative controls (P 0.001). Among controls, a fivefold increase in appendixes10 cm and a twofold increase in appendixes4 cm were observed. Half (9/18) of long appendicitis cases showed tip appendicitis at CT."Intermediate" appendiceal lengths (4-10 cm) are more frequently complicated by acute appendicitis, whereas both "long" (10 cm) and "short" (4 cm) lengths are more frequently observed in unaffected adults.

To assess alternative diagnoses in adults undergoing computed tomography (CT) for suspected acute appendicitis in routine clinical practice.This retrospective study was HIPAA compliant and institutional review board approved; informed consent was waived. A total of 1571 consecutive adults were referred from emergency department or urgent care settings for evaluation of suspected acute appendicitis at a single academic medical center from January 2006 to December 2009. Diagnoses given by board-certified radiologists at nonfocused abdominopelvic CT and ultimate clinical diagnoses by a combination of clinical, surgical, pathologic, and other radiologic findings were analyzed. Comparisons were made by using the Fisher exact test and Mann-Whitney test, where appropriate, with a two-tailed P value of less than .05 used as the criterion for statistical significance.A specific diagnosis at CT examination was made in 867 of 1571 (55.2%) patients. Acute appendicitis was favored in 371 of 1571 (23.6%) patients. An alternative diagnosis other than appendicitis was suggested in 496 of 1571 (31.6%) patients. Among patients with an alternative CT diagnosis, 204 of 496 (41.1%) were hospitalized and 109 of 496 (22.0%) underwent surgical or image-guided intervention for diagnoses other than appendicitis, compared with rates of 14.1% and 4.4%, respectively, among patients in whom a specific diagnosis was not made at CT (P.0001). The most common broad categories of disease included nonappendiceal gastrointestinal conditions (46.0%), gynecologic conditions (21.6%), genitourinary conditions (16.9%), and hepatopancreaticobiliary conditions (7.7%).In adult patients clinically suspected of having acute appendicitis, abdominopelvic CT frequently identifies an alternative cause for symptoms, which often requires hospitalization and surgery for treatment.

A significant amount of research has focused on the role of diffusion-weighted MRI (DW-MRI) in the management of patients with prostate cancer. Although uncertainties remain, a clearer picture of where this technique fits into clinical practice is now available. A combination of DW-MRI and T2-weighted MRI (T2W-MRI) demonstrates improved accuracy for lesion detection and localization compared with T2W-MRI alone, and has been suggested as a tool to guide tissue biopsy. DW-MRI could also have roles in active surveillance, evaluating treatment efficacy, and predicting disease recurrence. Furthermore, DW-MRI offers the exciting possibility of gathering information about tumor characteristics and aggressiveness in a noninvasive manner. Validation in large prospective multicenter trials is critical if this technique is to be integrated into current management algorithms for prostate cancer.

Use of preoperative computed tomography for suspected acute appendicitis has dramatically increased since the introduction of multidetector CT (MDCT) scanners.To evaluate the diagnostic performance of MDCT for suspected acute appendicitis in adults.Analysis of MDCT findings and clinical outcomes of consecutive adults referred for MDCT for suspected appendicitis from January 2000 to December 2009.Single academic medical center in the United States.2871 adults.Interpretation of nonfocused abdominopelvic MDCT scans by radiologists who were aware of the study indication. Posttest assessment of diagnostic performance of MDCT for acute appendicitis, according to the reference standard of final combined clinical, surgical, and pathology findings.675 of 2871 patients (23.5%) had confirmed acute appendicitis. The sensitivity, specificity, and negative and positive predictive values of MDCT were 98.5% (95% CI, 97.3% to 99.2%) (665 of 675 patients), 98.0% (CI, 97.4% to 98.6%) (2153 of 2196 patients), 99.5% (CI, 99.2% to 99.8%) (2153 of 2163 patients), and 93.9% (CI, 91.9% to 95.5%) (665 of 708 patients), respectively. Positive and negative likelihood ratios were 51.3 (CI, 38.1 to 69.0) and 0.015 (CI, 0.008 to 0.028), respectively. The overall rate of negative findings at appendectomy was 7.5% (CI, 5.8% to 9.7%) (54 of 716 patients), but would have decreased to 4.1% (28 of 690 patients) had surgery been avoided in 26 cases with true-negative findings on MDCT. The overall perforation rate was 17.8% (120 of 675 patients) but progressively decreased from 28.9% in 2000 to 11.5% in 2009. Multidetector computed tomography provided or suggested an alternative diagnosis in 893 of 2122 patients (42.1%) without appendicitis or appendectomy.Possible referral bias, because some patients whose appendicitis was difficult to diagnose on clinical grounds may not have been referred for MDCT for evaluation of suspected appendicitis.Multidetector computed tomography is a useful test for routine evaluation of suspected appendicitis in adults.None.

The true prevalence of urolithiasis in asymptomatic adults is unknown. Unenhanced computerized tomography represents the gold standard for detection. We evaluated the prevalence and symptomatic incidence of urolithiasis in a large cohort of asymptomatic adults using noncontrast computerized tomography.Low dose noncontrast computerized tomography was performed in 5,047 consecutive asymptomatic adults (mean age 56.9 years, 2,747 women and 2,300 men) between 2004 and 2008. Presence, size and location of urinary calculi were recorded. Screening prevalence as well as the incidence of symptomatic stone disease during a 10-year interval (1997 to 2007) was compared against previously established clinical risk factors.The screening prevalence of asymptomatic urolithiasis was 7.8% (395 of 5,047 adults) with an average of 2.1 stones per case (range 1 to 29) and a mean stone size of 3.0 mm (range 1 to 20). During a 10-year period 20.5% (81 of 395) of patients with stones (1.6% of entire screening cohort) had at least 1 symptomatic episode. Males were more likely to have urolithiasis than females (9.7% vs 6.3%, p0.001). Diabetes (9.0% vs 7.7%, p = 0.45), obesity (7.6% vs 7.9%, p = 0.72) and age 60 years or older (8.0% vs 7.7%, p = 0.73) did not affect prevalence, but diabetes and obesity did correlate with symptom development (p0.001 and p0.05, respectively).This objective population based assessment in a large asymptomatic cohort showed an 8% prevalence of urolithiasis. Most cases were unsuspected and remained asymptomatic. Although there was no correlation between asymptomatic urolithiasis and diabetes, obesity or older age, diabetes and obesity were associated with a higher incidence of symptoms over time.

Diffusion-weighted magnetic resonance imaging (DW-MRI) is considered part of the standard imaging protocol for the evaluation of patients with prostate cancer. It has been proven valuable as a functional tool for qualitative and quantitative analysis of prostate cancer beyond anatomical MRI sequences such as T2-weighted imaging. This review discusses ongoing controversies in DW-MRI acquisition, including the optimal number of b-values to be used for prostate DWI, and summarizes the current literature on the use of advanced DW-MRI techniques. These include intravoxel incoherent motion imaging, which better accounts for the non-mono-exponential behavior of the apparent diffusion coefficient as a function of b-value and the influence of perfusion at low b-values. Another technique is diffusion kurtosis imaging (DKI). Metrics from DKI reflect excess kurtosis of tissues, representing its deviation from Gaussian diffusion behavior. Preliminary results suggest that DKI findings may have more value than findings from conventional DW-MRI for the assessment of prostate cancer.