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We sought to compare the diagnostic performance of computed coronary tomography angiography (CCTA), computed tomography perfusion (CTP) and computed tomography fractional flow reserve (CT-FFR) for assessing the functional significance of coronary stenosis as defined by invasive fractional flow reserve (FFR), in patients with known or suspected coronary artery disease. CCTA has proven clinically useful for excluding obstructive CAD due to its high sensitivity and negative predictive value (NPV), however the ability of CTA to identify functionally significant CAD has remained challenging. We searched PubMed/Medline for studies evaluating CCTA, CTP or CT-FFR for the non-invasive detection of obstructive CAD as compared to catheter-derived FFR as the reference standard. Pooled sensitivity, specificity, PPV, NPV, likelihood ratios (LR), odds ratio (OR) of all diagnostic tests were assessed. Eighteen studies involving a total of 1535 patients were included. CTA demonstrated a pooled sensitivity of 0.92, specificity 0.43, PPV of 0.56 and NPV of 0.87 on a per-patient level. CT-FFR and CTP increased the specificity to 0.72 and 0.77 respectively (P=0.004 and P=0.0009)) resulting in higher point estimates for PPV 0.70 and 0.83 respectively. There was no improvement in the sensitivity. The CTP protocol involved more radiation (3.5 mSv CCTA VS 9.6 mSv CTP) and a higher volume of iodinated contrast (145 mL). In conclusion, CTP and CT-FFR improve the specificity of CCTA for detecting functionally significant stenosis as defined by invasive FFR on a per-patient level; both techniques could advance the ability to non-invasively detect the functional significance of coronary lesions.

BACKGROUND AND PURPOSE: CT is the imaging modality of choice to study the paranasal sinuses; unfortunately, it involves significant radiation dose. Our aim was to assess the diagnostic validity, image quality, and radiation-dose savings of dental conebeam CT in the evaluation of patients with suspected inflammatory disorders of the paranasal sinuses. MATERIAL AND METHODS: We prospectively studied 40 patients with suspected inflammatory disorders of the sinuses with dental conebeam CT and standard CT. Two radiologists analyzed the images independently, blinded to clinical information. The image quality of both techniques and the diagnostic validity of dental conebeam CT compared with the reference standard CT were assessed by using 3 different scoring systems. Image noise, signal-to-noise ratio, and contrast-to-noise ratio were calculated for both techniques. The absorbed radiation dose to the lenses and thyroid and parotid glands was measured by using a phantom and dosimeter chips. The effective radiation dose for CT was calculated. RESULTS: All dental conebeam CT scans were judged of diagnostic quality. Compared with CT, the conebeam CT image noise was 37.3% higher (P < .001) and the SNR of the bone was 75% lower (P < .001). The effective dose of our conebeam CT protocol was 23 mu sv. Compared with CT, the absorbed radiation dose to the lenses and parotid and thyroid glands with conebeam CT was 4%, 7.8%, and 7.3% of the dose delivered to the same organs by conventional CT (P < .001). CONCLUSIONS: Dental conebeam CT is a valid imaging procedure for the evaluation of patients with inflammatory sinonasal disorders.

OBJECTIVE. Glioblastoma and solitary metastatic lesions can be difficult to differentiate with conventional MRI. The use of diffusion-weighted MRI to better characterize peritumoral edema has been explored for this purpose, but the results have been conflicting. The purpose of this study was to test the hypothesis that the gradient of apparent diffusion coefficient (ADC) values in peritumoral edema-that is, the difference in ADC values from the region closest to the enhancing tumor and the one closest to the normal-appearing white matter-may be a marker for differentiating glioblastoma from a metastatic lesion. MATERIALS AND METHODS. Forty patients, 20 with glioblastoma and 20 with a solitary metastatic lesion, underwent diffusion-weighted brain MRI before surgical resection. The ADC values were retrospectively collected in the peritumoral edema in three positions: near, an intermediate distance from, and far from the core enhancing tumor (G1, G2, and G3). The ADC gradient in the peritumoral edema was calculated as the subtractions ADC(G3) - ADC(G1), ADC(G3) - ADC(G2), and ADC(G2) - ADC(G1). The ADC values in the enhancing tumor, peritumoral edema, ipsilateral normal-appearing white matter, contralateral healthy white matter, and CSF were also collected. RESULTS. A gradient of ADC values was found in the peritumoral edema of glioblastoma. The ADC values increased from the region close to the enhancing tumor (1.36 +/- 0.24 x 10(-3) mm(2)/s) to the area near the normal-appearing white matter (1.57 +/- 0.34 x 10(-3) mm(2)/s). In metastatic lesions, however, those values were nearly homogeneous (p = 0.04). CONCLUSION. The ADC gradient in peritumoral edema appears to be a promising tool for differentiating glioblastoma from a metastatic lesion.

Objective: The development of liver fibrosis and cirrhosis due to long-standing liver congestion is known to occur in adult patients with Fontan circulation. Hepatic elastography has shown to be a useful tool for the noninvasive assessment and staging of liver fibrosis in chronic liver diseases, although the utility of this technique in Fontan patients remains to be adequately studied. Methods: Twenty-one patients with Fontan circulation underwent an abdominal ultrasound and an acoustic radiation force impulse (ARFI) elastography. In order to compare the results from this group, a cohort of 14 healthy controls and another group containing 17 patients with cirrhosis were included. The association between the velocity values measured with elastography and clinical and analytical parameters were also studied. Results: Mean shear waves propagation velocity in liver tissue in the Fontan group was 1.86 ± 0.5 m/s, with 76% of patients over the cirrhosis threshold (1.55 m/s). The control group had a mean velocity of 1.09 ± 0.06 m/s, while the cirrhotic group obtained 2.71 ± 0.51 m/s. Seven patients with Fontan circulation had increased liver enzymes. Liver ultrasound showed evidence of chronic liver disease in six patients. Velocity values obtained in the presence or absence of analytical or liver ultrasound abnormalities showed significant differences in the univariate analysis ( P = .04 and P = .03 respectively). Conclusion: In conclusion, ARFI elastography showed increased wave propagation velocity values in the Fontan population suggesting increased liver stiffness which could be related to advanced fibrosis. A statistically significant association between ARFI values and the presence of analytical and ultrasound abnormalities has been demonstrated.

A 50-year-old man presented to the emergency department with a 4-day history of right lower quadrant pain that did notmigrate during that period of time. On examination, he tested positive for the Blumberg sign.Bloodanalysis showed leucocytosis, neutrophilia, andan increased level of C-reactive protein. Ultrasonographic (Figure, A) and computed tomographic images (Figure, B) showeda thickenedwall outpouching arising from a discreetly thickened appendix and inflamedsurroundingfat.Right-sidedcolonicdiverticulosiswasalso seen. Thepatient underwent an appendectomywith gross findings as shown in Figure, C. A

Purpose To evaluate the diagnostic performance of dual-energy (DE) computed tomography (CT) after thoracic endovascular aortic repair (TEVAR) of type B dissection, and to investigate the value of late delayed (LD) acquisition in endoleak detection and false lumen patency assessment. Materials and Methods Twenty-four patients with TEVAR for type B dissection underwent 53 tripe-phase CT examinations. Single-source unenhanced acquisition was followed by single-source arterial-phase and DE LD phase (300-s delay) imaging. Virtual noncontrast images were generated from DE acquisition. Two blinded radiologists retrospectively evaluated the cases in three reading sessions: session A (triphasic protocol), session B (virtual noncontrast and arterial phase), and session C (virtual noncontrast and arterial and LD phases). Endoleak detection accuracy during sessions B and C compared with session A (reference standard) was investigated. False lumen patency was assessed. Effective radiation dose was calculated. Results Session A revealed 37 endoleaks in 30 of 53 studies (56.6%). Session B revealed 31 of the 37 endoleaks, with one false-positive case, 83.8% sensitivity, 95.8% specificity, 79.3% negative predictive value, and 96.9% positive predictive value. Session C correctly depicted all 37 endoleaks, with one false-positive case, 100% sensitivity, 95.8% specificity, 100% negative predictive value, and 97.4% positive predictive value. Underestimation of false lumen patency was found in session B ( P = .013). Virtual noncontrast imaging resulted in 17% radiation exposure reduction. Conclusions Virtual noncontrast imaging can replace standard unenhanced images in follow-up after TEVAR of type B dissection, thus reducing radiation dose. Delayed-phase imaging is valuable in low-flow endoleaks detection and false lumen patency assessment.

Introduction Our routine laboratory critical value notification procedure is based on a short list of six fundamental critical values. The report system for our Stat laboratory is not based on this ‘short list’; instead, critical values are always reported according to the patient clinical context and the previous laboratory results. The aim of our work is to show how a critical value notification procedure based on a rigid list of values and thresholds can result in completely different results depending on whether the tests are requested in a stat or a routine manner. Material and methods We reviewed the number of critical value notifications based on the short list for the routine laboratory. For the stat laboratory, we studied the number of real notifications based on the pathologist validation of the individualised situation of the patient and calculated the number of notifications that would have been reported if the routine short list would have been used instead. Results The number of critical values that would have been reported if using the routine short list in stat laboratory was high when compared with the number of critical values that were really reported. Conclusions Using a rigid list of laboratory values to notify critical values resulted in completely different results depending on whether the tests were requested in stat or routine. Reporting only really unexpected values through an individual custom-made reporting procedure may avoid the wasting of time and resources and raising false alarms among referring physicians and patients.

The objective of our study was to evaluate the diagnostic performance of dual-source dual-energy CT (DECT) in the detection of endoleaks after thoracic endovascular aortic repair for thoracic aortic aneurysm and to investigate if a double-phase (arterial and dual-energy late delayed phase) or a single-phase (dual-energy late delayed phase) acquisition can replace the standard triphasic protocol.All DECT examinations performed for evaluation after thoracic endovascular aortic repair during a 30-month period were retrospectively reviewed. An initial single-source unenhanced acquisition was followed by a single-source arterial phase acquisition and a dual-energy 300-second late delayed phase acquisition. "Virtual noncontrast images" were generated from the dual-energy acquisition. Two independent and blinded radiologists evaluated the cases during three reading sessions: session A (triphasic protocol: standard unenhanced, arterial phase, and late delayed phase), session B (virtual noncontrast and late delayed phase), and session C (virtual noncontrast, arterial phase, and late delayed phase). The diagnostic accuracies of sessions B and C were calculated using session A as the reference standard. Contrast-to-noise ratios and effective radiation doses were calculated.Forty-eight patients (mean age, 66 years; age range, 19-84 years) underwent 74 triple-phase CT examinations. The single-phase studies (session B) were characterized by 85.7% sensitivity, 100% specificity, 100% negative predictive value (NPV), and 94.6% positive predictive value (PPV). The dual-phase study (session C) revealed 100% sensitivity, 100% specificity, 100% NPV, and 100% PPV. The use of the dual-phase protocol and single-phase protocol resulted in a radiation exposure reduction of 19.5% and 64.1%, respectively.Virtual noncontrast and late delayed phase images reconstructed from a single DECT acquisition can replace the standard triphasic protocol in follow-up examinations after thoracic endovascular aortic repair, thereby providing a significant dose reduction.

Nocardiosis is an infrequent but severe infection that primarily affects the lung and thence is able to produce disseminated disease. Prompt diagnosis of pulmonary and disseminated nocardiosis is of utmost importance in solid-organ transplant recipients to reduce mortality. Knowledge of the different radiological manifestations in the appropriate clinical setting is key to successful management of these patients. The aim of this review is to describe the radiological features of nocardiosis in immunosuppressed patients, particularly in solid-organ transplant recipients.

Total bilirubin tests are individually inexpensive but can result in huge costs to healthcare systems worldwide, because they are very commonly requested. The main objective of this study was to evaluate the diagnostic accuracy of the icteric index, a test with zero reagent cost, as a preliminary biomarker to decide when total bilirubin measurement is necessary.We retrospectively reviewed all the requested total bilirubin values and their corresponding icteric index results in a 2-year period (2010-11). Receiver operating characteristic (ROC) curve analysis was used to determine the optimal icteric index cut-off value to discriminate between normal and abnormal bilirubin values (20.5 μmol/l;1.2 mg/dl).The study included total bilirubin and icteric index results of 100,207 patients. The ROC curve analysis suggested 34.2 μmol/l (2 mg/dl) as the optimal icteric index threshold to identify abnormal bilirubin values. The area under the curve was 0.981. Regardless of the patient population studied (primary care, hospital and different individual hospital departments), sensitivity was greater than 94% and specificity was over 98%. Likelihood ratio values provided strong evidence that total bilirubin is less than 20.5 μmol/l (1.2 mg/dl) when the icteric index is less than 34.2 μmol/l (2 mg/dl).This study supports the use of the icteric index to identify patients with abnormal total bilirubin values. Considerable economic savings can be achieved if this strategy is applied on a clinical daily basis. Its implementation and report should be discussed and planned by laboratory professionals together with requesting physicians.

Objectives The objectives of this study are to introduce the “alert value reporting” concept in primary care setting, to propose a list of chemistry and hematology alert limit tests that can be chosen for that strategy, to show how this notification procedure can be designed and established, and finally to evaluate the effectiveness and physicians' satisfaction regarding the proposed approach. In contrast to critical value reporting, alert value reporting would not allude to a result that may imply a life-threatening situation, but would indicate that an early diagnostic/therapeutic action would improve the patient's management and quality of life. Design and methods A list of chemistry and hematology alert limit tests to be used for the strategy was agreed upon between laboratory professionals and general practitioners. Next, a retrospective 12-month study involving more than 1 million laboratory tests was made to check how many of these alert values would have been communicated if these theoretical alert values had been applied. A prospective analysis of every reported alert value during 6 months was carried out to assess the intervention effectiveness and the requesting physician's satisfaction with the new strategy. Results The alert value reporting was successfully executed. 20% of the reported alert values motivated the decision to reschedule the next patient's appointment. 90% of physicians considered alert value reporting as an interesting strategy to be continued. Conclusions Alert value reporting strategy motivated changes in patient's management. Further studies are needed to test if this approach can contribute to enhance patient safety and decision-making.

Vascular malformations and tumors comprise a wide, heterogeneous spectrum of lesions that often represent a diagnostic and therapeutic challenge. Frequent use of an inaccurate nomenclature has led to considerable confusion. Since the treatment strategy depends on the type of vascular anomaly, correct diagnosis and classification are crucial. Magnetic resonance (MR) imaging is the most valuable modality for classification of vascular anomalies because it accurately demonstrates their extension and their anatomic relationship to adjacent structures. A comprehensive assessment of vascular anomalies requires functional analysis of the involved vessels. Dynamic time-resolved contrast material-enhanced MR angiography provides information about the hemodynamics of vascular anomalies and allows differentiation of high-flow and low-flow vascular malformations. Furthermore, MR imaging is useful in assessment of treatment success and establishment of a long-term management strategy. Radiologists should be familiar with the clinical and MR imaging features that aid in diagnosis of vascular anomalies and their proper classification. Furthermore, they should be familiar with MR imaging protocols optimized for evaluation of vascular anomalies and with their posttreatment appearances. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.315105213/-/DC1.

Purpose: To develop an automated segmentation method to differentiate the ventilated lung volume on 3He magnetic resonance imaging (MRI). Materials and Methods: Computational processing (CP) for each subject consisted of the following three essential steps: 1) inhomogeneity bias correction, 2) whole lung segmentation, and 3) subdivision of the lung segmentation into regions of similar ventilation. Evaluation consisted of two comparative analyses: i) comparison of the number of defects scored by two human readers in 43 subjects, and ii) simultaneous truth and performance level estimation (STAPLE) in 18 subjects in which the ventilation defects were manually segmented by four human readers. Results: There was excellent correlation between the number of ventilation defects tabulated by CP and reader #1 (intraclass correlation coefficient [ICC] = 0.86), CP and reader #2 (ICC = 0.85), and between the two readers (ICC = 0.97). The STAPLE results from the second analysis yielded the following sensitivity/specificity numbers: CP (0.898/0.905), radiologist #1 (0.743/0.897), radiologist #2 (0.501/0.985), radiologist #3 (0.898/0.848), and the first author (0.600/0.984). Conclusion: We developed and evaluated an automated method for quantifying the ventilated lung volume on 3He MRI. The findings strongly indicate that our proposed algorithmic processing may be a reliable, automatic method for quantitating ventilation defects. J. Magn. Reson. Imaging 2011;. © 2011 Wiley-Liss, Inc.

A 10-year-old girl presented with a 4-month history of headache and with a normal examination. MRI showed a multi-cyst mesencephalic lesion isointense relative to CSF on all sequences; there was mass effect on the aqueduct with obstructive hydrocephalus (figure). Infections, …