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Objectives To investigate intra-patient variability of iodine concentration (IC) between three different dual-energy CT (DECT) platforms and to test different normalization approaches. Methods Forty-four patients who underwent portal venous phase abdominal DECT on a dual-source (dsDECT), a rapid kVp switching (rsDECT), and a dual-layer detector platform (dlDECT) during cancer follow-up were retrospectively included. IC in the liver, pancreas, and kidneys and different normalized ICs (NIC PV :portal vein; NIC AA :abdominal aorta; NIC ALL :overall iodine load) were compared between the three DECT scanners for each patient. A longitudinal mixed effects analysis was conducted to elucidate the effect of the scanner type, scan order, inter-scan time, and contrast media amount on normalized iodine concentration. Results Variability of IC was highest in the liver (dsDECT vs. dlDECT 28.96 (14.28–46.87) %, dsDECT vs. rsDECT 29.08 (16.59–62.55) %, rsDECT vs. dlDECT 22.85 (7.52–33.49) %), and lowest in the kidneys (dsDECT vs. dlDECT 15.76 (7.03–26.1) %, dsDECT vs. rsDECT 15.67 (8.86–25.56) %, rsDECT vs. dlDECT 10.92 (4.92–22.79) %). NIC ALL yielded the best reduction of IC variability throughout all tissues and inter-scanner comparisons, yet did not reduce the variability between dsDECT vs. dlDECT and rsDECT, respectively, in the liver. The scanner type remained a significant determinant for NIC ALL in the pancreas and the liver ( F -values, 12.26 and 23.78; both, p < 0.0001). Conclusions We found tissue-specific intra-patient variability of IC across different DECT scanner types. Normalization mitigated variability by reducing physiological fluctuations in iodine distribution. After normalization, the scanner type still had a significant effect on iodine variability in the pancreas and liver. Clinical relevance statement Differences in iodine quantification between dual-energy CT scanners can partly be mitigated by normalization, yet remain relevant for specific tissues and inter-scanner comparisons, which should be taken into account at clinical routine imaging. Key Points • Iodine concentration showed the least variability between scanner types in the kidneys (range 10.92–15.76%) and highest variability in the liver (range 22.85–29.08%). • Normalizing tissue-specific iodine concentrations against the overall iodine load yielded the greatest reduction of variability between scanner types for 2/3 inter-scanner comparisons in the liver and for all (3/3) inter-scanner comparisons in the kidneys and pancreas, respectively. • However, even after normalization, the dual-energy CT scanner type was found to be the factor significantly influencing variability of iodine concentration in the liver and pancreas.

Objective To assess the feasibility of a proposed pancreatic protocol CT generated from portal-venous phase (PVP) dual-energy CT (DECT) acquisition and its impact on image quality, lesion conspicuity, and arterial visualization/involvement. Methods We included 111 patients (mean age, 66.8 years) who underwent pancreatic protocol DECT (pancreatic phase, PP, and PVP). The original DECT acquisition was used to create two data sets—standard protocol (50 keV PP/65 keV PVP) and proposed protocol (40 keV/65 keV PVP). Three reviewers evaluated the two data sets for image quality, lesion conspicuity, and arterial visualization/involvement using a 5-point scale. The signal-to-noise ratio (SNR) of pancreas and lesion-to-pancreas contrast-to-noise ratio (CNR) was calculated. Qualitative scores, quantitative parameters, and dose-length product (DLP) were compared between standard and proposed protocols. Results The image quality, SNR of pancreas, and lesion-to-pancreas CNR of the standard and proposed protocol were comparable ( p = 0.11–1.00). Lesion conspicuity was comparable between the standard and proposed protocols for pancreatic ductal adenocarcinoma ( p = 0.55) and pancreatic cysts ( p = 0.28). The visualization of larger arteries and arterial involvement were comparable between the two protocols ( p = 0.056–1.00) while the scores were higher for smaller vessels in the standard protocol ( p < 0.0001–0.0015). DLP of the proposed protocol (670.4 mGy·cm) showed a projected 42% reduction than the standard protocol (1145.9 mGy·cm) ( p < 0.0001). Conclusion Pancreatic protocol CT generated from a single PVP DECT acquisition is feasible and could potentially be an alternative to the standard pancreatic protocol with PP and PVP. Key Points • The lesion conspicuity for focal pancreatic lesions was comparable between the proposed protocol and standard dual-phase pancreatic protocol CT. • Qualitative and quantitative image assessments were almost comparable between two protocols. • The radiation dose of a proposed protocol showed a projected 42% reduction from the conventional protocol.

Infarcts and ischemia of abdominal organs may present with acute abdominal pain, and early diagnosis is crucial to prevent morbidity and mortality. Unfortunately, some of these patients present in poor clinical conditions to the emergency department, and imaging specialists are crucial for optimal outcomes. Although the radiological diagnosis of abdominal infarcts is often straightforward, it is vital to use the appropriate imaging modalities and correct imaging techniques for their detection. Additionally, some non-infarct-related abdominal pathologies may mimic infarcts, cause diagnostic confusion, and result in delayed diagnosis or misdiagnosis. In this article, we aimed to outline the general imaging approach, present cross-sectional imaging findings of infarcts and ischemia in several abdominal organs, including but not limited to, liver, spleen, kidneys, adrenals, omentum, and intestinal segments with relevant vascular anatomy, discuss possible differential diagnoses and emphasize important clinical/radiological clues that may assist radiologists in the diagnostic process.

Two methods were compared for the detection of small lymph-node metastases in men with prostate cancer: conventional magnetic resonance imaging (MRI) and MRI performed 24 hours after the intravenous injection of lymph-node–seeking nanoparticles containing an iron oxide core. The latter method proved superior to conventional MRI in sensitivity and specificity. Better detection with MRI after injection of iron oxide nanoparticles. In 2001, about 198,000 new cases of prostate cancer were diagnosed in the United States and 31,500 men died of the disease. 1 The natural history and aggressiveness of the disease vary widely, and the means to identify men with clinically occult lymph-node metastases is greatly needed. 2 – 8 The adverse prognostic implications of lymph-node metastases have been widely established. 9 , 10 Magnetic resonance imaging (MRI) provides images with excellent anatomical detail and soft-tissue contrast but is relatively insensitive for the detection of lymph-node metastases. 11 However, the results of MRI can be improved by using different imaging agents and acquisition techniques. 12 – 14 In . . .

Percutaneous drainage is the standard treatment for perforated appendicitis with abscess. We studied factors associated with complete resolution (CR) with percutaneous drainage alone. Ninety-eight patients underwent percutaneous drainage for acute appendicitis complicated by abscess (October 1990 to September 2010). CR was defined as clinical recovery, resolution of the abscess on imaging, and drain removal without recurrence. Patients achieving CR were compared with patients not achieving CR. The rate of CR was 78.6% (n = 77). Abscess grade was the only radiological factor associated with CR (P = .007). The CR rate was higher with transgluteal drainage (90.9% vs 79.2%) than with other anatomic approaches (P = .018) and higher with computed tomography-guided drainage than with ultrasound-guided drainage (82.7% vs 64.3%, P = .046). CR was more likely to be achieved in patients with lower abscess grade, computed tomography-guided drainage, and a transgluteal approach. •This is the largest retrospective study of percutaneous appendiceal abscess drainage.•Low abscess grade was associated with success. Abscess size was not significant.•CT guidance and transgluteal approach were associated with success.•Postdrainage fistulas occur 13% of the time and most of them close spontaneously.

Tumors of the genital system are common and imaging is of crucial importance for their detection and diagnosis. Several non-neoplastic diseases may mimic these tumors and differential diagnosis may be difficult in certain cases. Misdiagnosing non-neoplastic diseases as tumor may prompt unnecessary medical treatment or surgical interventions. In this article, we aimed to present the imaging characteristics of non-neoplastic diseases of the male and female genital systems that may mimic neoplastic processes. Increasing awareness of the imaging specialists to these entities may have a severe positive impact on the management of these patients.

Purpose To evaluate the effect of CT perfusion (CTp) protocol modifications on quantitative perfusion parameters, radiation dose and data processing time. Materials & methods CTp datasets of 30 patients (21M:9F) with rectal ( n  = 24) or retroperitoneal ( n  = 6) tumours were studied. Standard CTp protocol included 50 sec cine-phase (0.5 sec/rotation) and delayed-phase after 70 ml contrast bolus at 5–7 ml/sec. CTp-data was sub-sampled to generate modified datasets ( n  = 105) with cine-phase( n  = 15) alone, varying cine-phase duration (20-40 sec, n  = 45) and varying temporal sampling-interval (1–3 sec, n  = 45). The estimated CTp parameters (BF,BV,MTT&PS) and radiation dose of standard CTp served as reference for comparison. Results CTp with 50 sec cine-phase showed moderate to high correlation with standard CTp for BF&MTT ( r  = 0.96&0.85) and low correlation for BV (0.75, p  = 0.04). Limiting cine-phase duration to 30 sec demonstrated comparable results for BF&MTT, while considerable variation in CTp values existed at 20 sec. There was moderate-to-high correlation of CTp parameters with sampling interval of 1&2 sec ( r  = 0.83–0.97, p  > 0.05), while at 3 sec only BF showed high correlation ( r  = 0.96, p  = 0.05). Increasing sampling interval (47–60%) and reducing cine-phase duration substantially reduced dose(30.8–65%) which paralleled reduced data processing time (3–10 min). Conclusion Limiting CTp cine-phase to 30 sec results in comparable BF&MTT values and increasing cine-phase sampling interval to 2 sec provides good correlation for all CTp parameters with substantial dose reduction and improved computational efficiency.

Despite the success of cross-sectional imaging in evaluating hepatopancreatobiliary system malignancies, several non-malignant disease processes may closely mimic malignancy. Differentiating these benign diseases from malignancy may be difficult, or even impossible, even in the hands of experienced imagers. In this manuscript, we present benign mimics involving the hepatopancreatobiliary system and try to increase awareness of these potential pitfalls.

Objectives To assess the impact of dual-energy CT (DECT) utilization in practice by measuring the readers’ confidence, the need for additional image requests, and diagnostic performance in renal lesion assessment, compared to single-energy CT (SECT) using contrast-enhanced MRI to establish the reference standard. Materials and methods Sixty-nine patients (M/F = 47/22) who underwent a dual-phase renal SECT ( n = 34) or DECT ( n = 35) and had a contrast-enhanced MRI within 180 days were retrospectively collected. Three radiologists assessed images on different sessions (SECT, DECT, and MRI) for (1) likely diagnosis (enhancing/non-enhancing); (2) diagnostic confidence (5-point Likert scale); (3) need for additional imaging test (yes/no); and (4) need for follow-up imaging (yes/no). Diagnostic accuracy was compared using AUC; p value < 0.05 was considered significant. Results One hundred fifty-six lesions consisting of 18% enhancing ( n = 28/156, mean size: 30.37 mm, range: 9.9–94 mm) and 82% non-enhancing ( n = 128/156, mean size: 23.91 mm, range: 5.0–94.2 mm) were included. The confidence level was significantly lower for SECT than their MRI (4.50 vs. 4.80, p value < 0.05) but not significantly different for DECT and the corresponding MRI (4.78 vs. 4.78, p > 0.05). There were significantly more requests for additional imaging in the SECT session than the corresponding MRI (20% vs. 4%), which was not significantly different between DECT and their MRI counterpart session (5.7% vs. 4.9%). Inter-reader agreement was almost perfect for DECT and MRI (kappa: 0.8–1) and substantial in SECT sessions (kappa: 0.6–0.8) with comparable diagnostic accuracy between SECT, DECT, and MRI ( p value > 0.05). Conclusion Single-phase DECT allows confident and reproducible characterization of renal masses with fewer recommendation for additional and follow-up imaging tests than dual-phase SECT and a performance similar to MRI. Key Points • DECT utilization leads to similar additional image requests to MRI (5.7% vs. 4.9%, p value > 0.05), whereas single-energy CT utilization leads to significantly higher image requests (20% vs. 4%, p value < 0.05). • DECT and MRI utilization bring highly reproducible results with almost perfect inter-reader agreement (kappa: 0.8–1), better than the inter-reader agreement in SECT utilization (kappa: 0.6–0.8). • Readers’ confidence was not significantly altered between DECT and their MRI readout session (p value > 0.05). In contrast, confidence in the diagnosis was significantly lower in the SECT session than their MRI readout (p value < 0.05).

Kidney neoplasms are common diseases with varying prognoses depending on the subtype of the tumor. The most common solid lesion of the kidney is renal cell carcinoma, and the treatment is typically surgical removal. With increasing use of cross-sectional imaging in the last two decades, the detection of renal lesions has significantly increased, especially in asymptomatic patients who are scanned for other reasons. In this article, we present the imaging findings of rare solid benign primary kidney neoplasms including renal leiomyoma, reninoma, carcinoid tumor, metanephric adenoma, solitary fibrous tumor of the kidney, lipomatous hemangiopericytoma of the kidney, renal schwannoma, inflammatory myofibroblastic tumor of the kidney, extramedullary hematopoiesis in the kidney, and extranodal renal Rosai-Dorfman disease. Accurate preoperative or prebiopsy diagnoses of these lesions are unusual; however, informed radiologists may sometimes be able to favorably change the patient management and treatment.