Contrast enhanced ultrasound eases interpretation of an unclear renal tumor in addition to CT, MRI and histological findings--a case report in a young patient

Renal cancer represents accounts for approximately 3% of all adult malignancies with a rising incidence. Incidental diagnosis is mostly based upon ultrasound (US). US and Computed tomography (CT) are the standard imaging modalities for detecting renal cell cancer (RCC). Differentiation between malignant and benign renal tumors is of utmost importance. Contrast enhanced ultrasound (CUS) seems to be a promising new diagnostic option for diagnosis and preoperative treatment planning for patients with renal cancer. It is an additional examination to baseline ultrasound and CT. We report a case of a 37-year-old woman with a papillary renal cell cancer in which CUS helped to differentiate dignity of the tumor. CUS is an additional examination to baseline ultrasound and CT. It is a less invasive technique than contrast enhanced CT and shows even slight tumor blood flow. In addition it may allow a more rapid diagnosis, because of its bedside availability.

Virtopsy - the concept of a centralized database in forensic medicine for analysis and comparison of radiological and autopsy data

Recent developments in clinical radiology have resulted in additional developments in the field of forensic radiology. After implementation of cross-sectional radiology and optical surface documentation in forensic medicine, difficulties in the validation and analysis of the acquired data was experienced. To address this problem and for the comparison of autopsy and radiological data a centralized database with internet technology for forensic cases was created. The main goals of the database are (1) creation of a digital and standardized documentation tool for forensic-radiological and pathological findings; (2) establishing a basis for validation of forensic cross-sectional radiology as a non-invasive examination method in forensic medicine that means comparing and evaluating the radiological and autopsy data and analyzing the accuracy of such data; and (3) providing a conduit for continuing research and education in forensic medicine. Considering the infrequent availability of CT or MRI for forensic institutions and the heterogeneous nature of case material in forensic medicine an evaluation of benefits and limitations of cross-sectional imaging concerning certain forensic features by a single institution may be of limited value. A centralized database permitting international forensic and cross disciplinary collaborations may provide important support for forensic-radiological casework and research.

Virtopsy: fatal stab wounds to the skull--the relevance of ante-mortem and post-mortem radiological data in case reconstructions

Homicides with a survival of several days are not uncommon in forensic routine work. Reconstructions of these cases by autopsy alone are very difficult and may occasionally lead to unsatisfying results. For the medico-legal reconstruction of these cases, ante-mortem and post-mortem radiological imaging should always be included in the expertise. We report on a case of fatal penetrating stab wounds to the skull in which a case reconstruction was only possible by combining the radiological ante- and post-mortem data with the autopsy findings.

Coronary artery stent geometry and in-stent contrast attenuation with 64-slice computed tomography

We aimed at assessing stent geometry and in-stent contrast attenuation with 64-slice CT in patients with various coronary stents. Twenty-nine patients (mean age 60 +/- 11 years; 24 men) with 50 stents underwent CT within 2 weeks after stent placement. Mean in-stent luminal diameter and reference vessel diameter proximal and distal to the stent were assessed with CT, and compared to quantitative coronary angiography (QCA). Stent length was also compared to the manufacturer's values. Images were reconstructed using a medium-smooth (B30f) and sharp (B46f) kernel. All 50 stents could be visualized with CT. Mean in-stent luminal diameter was systematically underestimated with CT compared to QCA (1.60 +/- 0.39 mm versus 2.49 +/- 0.45 mm; P < 0.0001), resulting in a modest correlation of QCA versus CT (r = 0.49; P < 0.0001). Stent length as given by the manufacturer was 18.2 +/- 6.2 mm, correlating well with CT (18.5 +/- 5.7 mm; r = 0.95; P < 0.0001) and QCA (17.4 +/- 5.6 mm; r = 0.87; P < 0.0001). Proximal and distal reference vessel diameters were similar with CT and QCA (P = 0.06 and P = 0.03). B46f kernel images showed higher image noise (P < 0.05) and lower in-stent CT attenuation values (P < 0.001) than images reconstructed with the B30f kernel. 64-slice CT allows measurement of coronary artery in-stent density, and significantly underestimates the true in-stent diameter compared to QCA.

Effects of non-ionic iodinated contrast media on patient heart rate and pressures during intra-cardiac or intra-arterial injection

PURPOSE: To compare the effects on heart rate (HR), on left ventricular (LV) or arterial pressures, and the general safety of a non-ionic low-osmolar contrast medium (CM) and a non-ionic iso-osmolar CM in patients undergoing cardiac angiography (CA) or peripheral intra-arterial digital subtraction angiography (IA-DSA). MATERIALS AND METHODS: Two double-blind, randomized studies were conducted in 216 patients who underwent CA (n=120) or peripheral IA-DSA (n=96). Patients referred for CA received a low-osmolar monomeric CM (iomeprol-350, n=60) or an iso-osmolar dimeric CM (iodixanol-320; n=60). HR and LV peak systolic and end-diastolic pressures were determined before and after the first injection during left and right coronary arteriography and left ventriculography. Monitoring for all types of adverse event (AE) was performed for 24 h following the procedure. t-tests were performed to compare CM for effects on HR. Patients referred for IA-DSA received iomeprol-300 (n=49) or iodixanol-320 (n=47). HR and arterial blood pressure (BP) were evaluated before and after the first 4 injections. Monitoring for AE was performed for 4 h following the procedure. Repeated-measures ANOVA was used to compare mean HR changes across the first 4 injections, whereas changes after the first injection were compared using t-tests. RESULTS: No significant differences were noted between iomeprol and iodixanol in terms of mean changes in HR during left coronary arteriography (p=0.8), right coronary arteriography (p=0.9), and left ventriculography (p=0.8). In patients undergoing IA-DSA, no differences between CM were noted for effects on mean HR after the first injection (p=0.6) or across the first 4 injections (p=0.2). No significant differences (p>0.05) were noted in terms of effects on arterial BP in either study or on LV pressures in patients undergoing CA. Non-serious AE considered possibly CM-related (primarily headache and events affecting the cardiovascular and digestive systems) were reported more frequently by patients undergoing CA and more frequently after iodixanol (14/60 [23.3%] and 2/47 [4.3%]; CA and IA-DSA, respectively) than iomeprol (10/60 [16.7%] and 1/49 [2%], respectively). CONCLUSIONS: Iomeprol and iodixanol are safe and have equally negligible effects on HR and LV pressures or arterial BP during and after selective intra-cardiac injection and peripheral IA-DSA. CLINICAL APPLICATION: Iomeprol and iodixanol are safe and equally well tolerated with regard to cardiac rhythm and clinical preference should be based on diagnostic image quality alone.

Multi-detector row CT of the small bowel: peak enhancement temporal window--initial experience

PURPOSE: To prospectively determine quantitatively and qualitatively the timing of maximal enhancement of the normal small-bowel wall by using contrast material-enhanced multi-detector row computed tomography (CT). MATERIALS AND METHODS: This HIPAA-compliant study was approved by the institutional review board. After information on radiation risk was given, written informed consent was obtained from 25 participants with no history of small-bowel disease (mean age, 58 years; 19 men) who had undergone single-level dynamic CT. Thirty seconds after the intravenous administration of contrast material, a serial dynamic acquisition, consisting of 10 images obtained 5 seconds apart, was performed. Enhancement measurements were obtained over time from the small-bowel wall and the aorta. Three independent readers qualitatively assessed small-bowel conspicuity. Quantitative and qualitative data were analyzed during the arterial phase, the enteric phase (which represented peak small-bowel mural enhancement), and the venous phase. Statistical analysis included paired Student t test and Wilcoxon signed rank test with Bonferroni correction. A P value less than .05 was used to indicate a significant difference. RESULTS: The mean time to peak enhancement of the small-bowel wall was 49.3 seconds +/- 7.7 (standard deviation) and 13.5 seconds +/- 7.6 after peak aortic enhancement. Enhancement values were highest during the enteric phase (P < .05). Regarding small-bowel conspicuity, images obtained during the enteric phase were most preferred qualitatively; there was a significant difference between the enteric and arterial phases (P < .001) but not between the enteric and venous phases (P = .18). CONCLUSION: At multi-detector row CT, peak mural enhancement of the normal small bowel occurs on average about 50 seconds after intravenous administration of contrast material or 14 seconds after peak aortic enhancement.

Radiological diagnosis of hepatocellular carcinoma

Treatment of hepatocellular carcinomas (HCC) is often complicated by the fact that early HCCs are mostly asymptomatic and the carcinoma is often discovered at an advanced stage. The aim of diagnostic imaging is to detect HCC at an early stage, when curative options are available. In recent years, there have been many efforts to improve early detection of small HCC. The purpose of this article is to describe the pertinent findings of HCCs in non-invasive, diagnostic imaging, including ultrasound, computed tomography, as well as modern magnetic resonance imaging techniques. Special emphasis is given to the frequently addressed difficulties of differentiation of precancerous lesions and small HCCs. A non-invasive diagnostic approach is considered with a review of the literature.

Hypervascular liver tumors: low tube voltage, high tube current multi-detector row CT for enhanced detection--phantom study

PURPOSE: To prospectively evaluate, for the depiction of simulated hypervascular liver lesions in a phantom, the effect of a low tube voltage, high tube current computed tomographic (CT) technique on image noise, contrast-to-noise ratio (CNR), lesion conspicuity, and radiation dose. MATERIALS AND METHODS: A custom liver phantom containing 16 cylindric cavities (four cavities each of 3, 5, 8, and 15 mm in diameter) filled with various iodinated solutions to simulate hypervascular liver lesions was scanned with a 64-section multi-detector row CT scanner at 140, 120, 100, and 80 kVp, with corresponding tube current-time product settings at 225, 275, 420, and 675 mAs, respectively. The CNRs for six simulated lesions filled with different iodinated solutions were calculated. A figure of merit (FOM) for each lesion was computed as the ratio of CNR2 to effective dose (ED). Three radiologists independently graded the conspicuity of 16 simulated lesions. An anthropomorphic phantom was scanned to evaluate the ED. Statistical analysis included one-way analysis of variance. RESULTS: Image noise increased by 45% with the 80-kVp protocol compared with the 140-kVp protocol (P < .001). However, the lowest ED and the highest CNR were achieved with the 80-kVp protocol. The FOM results indicated that at a constant ED, a reduction of tube voltage from 140 to 120, 100, and 80 kVp increased the CNR by factors of at least 1.6, 2.4, and 3.6, respectively (P < .001). At a constant CNR, corresponding reductions in ED were by a factor of 2.5, 5.5, and 12.7, respectively (P < .001). The highest lesion conspicuity was achieved with the 80-kVp protocol. CONCLUSION: The CNR of simulated hypervascular liver lesions can be substantially increased and the radiation dose reduced by using an 80-kVp, high tube current CT technique.

Renal oxygenation changes during acute unilateral ureteral obstruction: assessment with blood oxygen level-dependent mr imaging--initial experience

PURPOSE: To prospectively determine if changes in intrarenal oxygenation during acute unilateral ureteral obstruction can be depicted with blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging. MATERIALS AND METHODS: The study was approved by the local ethics committee, and written informed consent was obtained from all patients. BOLD MR imaging was performed in 10 male patients (mean age, 45 years +/- 17 [standard deviation]; range, 20-73 years) with a distal unilateral ureteral calculus and in 10 healthy age-matched male volunteers to estimate R2*, which is inversely related to tissue Po(2). R2* values were determined in the cortex and medulla of the obstructed and the contralateral nonobstructed kidneys. To reduce external effects on R2*, the R2* ratio between the medulla and cortex was also analyzed. Statistical analysis was performed with nonparametric rank tests. P < .05 was considered to indicate a significant difference. RESULTS: All patients had significantly lower medullary and cortical R2* values in the obstructed kidney (median R2* in medulla, 10.9 sec(-1) [range, 9.1-14.3 sec(-1)]; median R2* in cortex, 10.4 sec(-1) [range, 9.7-11.3 sec(-1)]) than in the nonobstructed kidney (median R2* in medulla, 17.2 sec(-1) [range, 14.6-23.2 sec(-1)], P = .005; median R2* in cortex, 11.7 sec(-1) [range, 11.0-14.0 sec(-1)], P = .005); values in the obstructed kidneys were also significantly lower than values in the kidneys of healthy control subjects (median R2* in medulla, 16.1 sec(-1) [range, 13.9-18.1 sec(-1)], P < .001; median R2* in cortex, 11.6 sec(-1) [range, 10.5-12.9 sec(-1)], P < .001). R2* ratios in the obstructed kidneys (median, 1.06; range, 0.85-1.27) were significantly lower than those in the nonobstructed kidneys (median, 1.49; range, 1.26-1.71; P = .005) and those in the kidneys of healthy control subjects (median, 1.38; range, 1.23-1.47; P < .001). In contrast, R2* ratios in the nonobstructed kidneys of patients were significantly higher than those in kidneys of healthy control subjects (P = .01). CONCLUSION: Increased oxygen content in the renal cortex and medulla occurs with acute unilateral ureteral obstruction, suggesting reduced function of the affected kidney.

Postmortem whole-body CT angiography: evaluation of two contrast media solutions

OBJECTIVE: The objective of our study was to establish a standardized procedure for postmortem whole-body CT-based angiography with lipophilic and hydrophilic contrast media solutions and to compare the results of these two methods. MATERIALS AND METHODS: Minimally invasive postmortem CT angiography was performed on 10 human cadavers via access to the femoral blood vessels. Separate perfusion of the arterial and venous systems was established with a modified heart-lung machine using a mixture of an oily contrast medium and paraffin (five cases) and a mixture of a water-soluble contrast medium with polyethylene glycol (PEG) 200 in the other five cases. Imaging was executed with an MDCT scanner. RESULTS: The minimally invasive femoral approach to the vascular system provided a good depiction of lesions of the complete vascular system down to the level of the small supplying vessels. Because of the enhancement of well-vascularized tissues, angiography with the PEG-mixed contrast medium allowed the detection of tissue lesions and the depiction of vascular abnormalities such as pulmonary embolisms or ruptures of the vessel wall. CONCLUSION: The angiographic method with a water-soluble contrast medium and PEG as a contrast-agent dissolver showed a clearly superior quality due to the lack of extravasation through the gastrointestinal vascular bed and the enhancement of soft tissues (cerebral cortex, myocardium, and parenchymal abdominal organs). The diagnostic possibilities of these findings in cases of antemortem ischemia of these tissues are not yet fully understood.