Influence of Varying Assessment Parameters on the Diagnostic Accuracy of Magnetic Resonance Imaging in the Local Staging of Prostate Cancer.

INTRODUCTION: There is a broad variability in the accuracy levels of MRI with regard to the local staging of prostate cancer (PCa). METHODS: A prospective analysis was conducted in patients with localized PCa with MRI of the prostate before radical prostatectomy. MRI and pathology findings were independently reviewed and reported based on a standardized map of the prostate with 16 regions of interest (ROIs). Diagnostic accuracy analysis of the MRI was performed using varying prostate-subpart sizes and varying cutoffs for the radiological probability for PCa presence. RESULTS: Seventy four patients were included. Using varying cutoff probabilities and varying sizes of prostate-subparts resulted in a broad range of sensitivity (6-88%) and specificity (38-100%). Lower probabilities of PCa presence and larger prostate-subparts resulted in higher sensitivity but lower specificity and vice versa. Best diagnostic performance was achieved by using prostate sextants and at least moderate probabilities for PCa presence; mean sensitivity and specificity were 38% (95% CI 13-75) and 95% (95% CI 88-98). CONCLUSION: The use of varying assessment parameters strongly affects the diagnostic accuracy of MRI in the local staging of PCa. Hence, precise and standardized reporting regarding these parameters is important. In our study, using at least moderate probabilities for PCa presence on MRI and prostatic sextants as ROI size was associated with best diagnostic performance.

Use of computed tomography and positron emission tomography/computed tomography for staging of local extent in patients with malignant pleural mesothelioma.

PURPOSE: The objective of this study was to determine the diagnostic value of computed tomography (CT) and positron emission tomography (PET)/CT for staging of malignant pleural mesothelioma (MPM) in patients undergoing induction chemotherapy. METHODS: Sixty-two patients (median age, 61 years; female: n = 9) with proven MPM underwent CT after induction chemotherapy. Of these, 28 underwent additional PET/CT. Extrapleural pneumonectomy was performed for pathological TNM staging. Clinical TNM stage was assessed by 3 independent readers. Relative and absolute underestimation and overestimation were compared with pathological tumor stage. Sensitivity, specificity, and accuracy for differentiation between stages T2 and T3 were assessed. Interobserver agreement between the readers was analyzed (κ). RESULTS: Positron emission tomography/CT and CT underestimated T stage in up to 30% of the cases. Positron emission tomography/CT had a higher accuracy for tumor extent compared with CT (PET/CT: 0.92; CT: 0.84). The accuracy for nodal staging was higher for CT than for PET/CT (PET/CT: 0.78; CT: 0.87). Concerning International Mesothelioma Interest Group classification, PET/CT improved the accuracy of preoperative staging compared with CT (PET/CT: 0.91; CT: 0.82). Interobserver agreement was moderate for CT (0.48-0.62) and good for PET/CT (0.64-0.83) for T staging. For nodal staging, interobserver agreement was fair to moderate for CT and good for PET/CT (CT: 0.37-0.51; PET/CT: 0.73-0.76). CONCLUSIONS: Positron emission tomography/CT is more accurate and has a lower interobserver variability for clinical intrathoracic staging of MPM compared with CT. Nevertheless PET/CT underestimated tumor stage in a substantial number of cases, showing the need for a more accurate imaging technology or approach.

MRI for characterization of primary tumors in the non-cirrhotic liver: added value of Gd-EOB-DTPA enhanced hepatospecific phase.

PURPOSE: To evaluate the added value of hepatospecific phase in Gd-EOB-DTPA enhanced magnetic resonance imaging (MRI) in patients with primary tumors in non-cirrhotic liver. METHODS: Twenty-nine patients (median, 39 years; range, 18-81 years; 11 male) underwent preoperative Gd-EOB-DTPA enhanced MRI including hepatospecific phase after 10 and 20 min of contrast injection at four institutions in Europe, North America and New Zealand. Images were evaluated by three different readers (R1-R3) who characterized liver tumors with and without consultation of the hepatospecific phase images. Confidence in diagnosis was scored on a visual analog scale from 1 to 10. Histopathology (adenoma, n=5; focal nodular hyperplasia, n=11 and hepatocellular carcinoma, n=13) in all patients served as the standard of reference. Differences were evaluated using the McNemar and Wilcoxon signed rank test. RESULTS: Without hepatospecific phase images available, 22 (76%), 19 (66%) and 19 (66%) of 29 tumors were characterized correctly by the three readers respectively. Mean confidence in diagnosis was 6.1, 5.7 and 5.8. With the hepatospecific phase included, characterization of liver tumors did not change significantly with 21 (72%), 23 (79%) and 19 (66%) of 29 tumors diagnosed correctly (p>0.05). According confidence ratings increased to 6.3, 6.5 and 7.7, respectively. Increase in diagnostic confidence was significant for R2 and R3 (p<0.05) and independent of reader's experience. CONCLUSION: The additional hepatospecific phase in Gd-EOB-DTPA enhanced MRI did not significantly increase diagnostic accuracy in characterization of primary tumors in the non-cirrhotic liver. However, 2/3 readers showed a significant increase in diagnostic confidence after consultation of the hepatospecific phase.

Diagnostic performance of a non-contrast-enhanced magnetic resonance imaging protocol for potential living related kidney donors.

RATIONALE AND OBJECTIVES: The objective of the study was to evaluate the performance of a non-contrast-enhanced magnetic resonance (MR) imaging protocol for preoperative screening of living related kidney donors. MATERIALS AND METHODS: Forty consecutive subjects (mean age 52.2 ± 11.3 years, range 29-73 years) underwent MR imaging with T2-weighted sequences (coronal and axial plane), with a non-contrast-enhanced respiratory-gated three-dimensional steady state free precession MR angiography (NCE-MRA) sequence and with contrast-enhanced magnetic resonance MR angiography (CE-MRA) sequences in the arterial and venous phases. Two blinded readers independently assessed arterial and venous anatomy and potential kidney lesions. Results of non-contrast-enhanced images were compared to CE-MRA and in a subgroup of 21 subjects to surgery as standard of reference. RESULTS: Regarding arterial anatomy, NCE-MRA yielded sensitivity, specificity, and accuracy of 100%, 89%, and 91% compared to CE-MRA. Three kidneys were found to have more accessory renal arteries at NCE-MRA than at CE-MRA. In the subgroup of 21 subjects, 1 surgically proven accessory artery was depicted with NCE-MRA but not with CE-MRA. Accuracy of T2-weighted images regarding accessory veins or variant venous course was 99%, with one missed circumaortic vein on T2-weighted images. Two simple cysts were missed on T2-weighted and NCE-MRA but not on CE-MRA images. CONCLUSION: A non-contrast-enhanced MR imaging protocol including NCE-MRA and T2-weighted images allows for the accurate screening of living related kidney donors and may serve as an alternative to CE-MRA.

Accuracy and confidence of Gd-EOB-DTPA enhanced MRI and diffusion-weighted imaging alone and in combination for the diagnosis of liver metastases.

PURPOSE: To evaluate the accuracy and confidence in diagnosing liver metastases using combined gadolinium-EOB-DTPA (Gd-EOB-DTPA) enhanced magnetic resonance imaging (MRI)/diffusion-weighted imaging (DWI) in comparison to Gd-EOB-DTPA enhanced MRI and DWI alone. MATERIALS AND METHODS: Forty-three patients (age, 58 ± 13 years) with 89 liver lesions (28 benign, 61 malignant) underwent liver MRI for suspected liver metastases. Three image sets (DWI, Gd-EOB-DTPA and combined Gd-EOB-DTPA/DWI) in combination with unenhanced T1- and T2-weighted images were reviewed by three readers. Detection rates of focal liver lesions were assessed and diagnostic accuracy was evaluated by calculating the areas under the receiver-operating-characteristics curve (AUC). Confidence in diagnosis was evaluated on a 3-point scale. Histopathology and imaging follow-up served as the standard of reference. RESULTS: Detection of liver lesions and confidence in final diagnosis for all readers were significantly higher for the combined Gd-EOB-DTPA/DWI dataset than for DWI. The combination of DWI and Gd-EOB-DTPA rendered a significantly higher confidence in final diagnosis (2.44 vs. 2.50) than Gd-EOB-DTPA alone for one reader. For two readers, accuracy in diagnosis of liver metastases was significantly higher for Gd-EOB-DTPA/DWI (AUCs of 0.84 and 0.83) than for DWI datasets (AUCs of 0.73 and 0.72). Adding DWI to Gd-EOB-DTPA did not significantly increase diagnostic accuracy as compared to Gd-EOB-DTPA imaging alone. CONCLUSION: Addition of DWI sequences to Gd-EOB-DTPA enhanced MRI did not significantly increase diagnostic accuracy as compared to Gd-EOB-DTPA enhanced MRI alone in the diagnosis of liver metastases. However, the increase in diagnostic confidence might justify acquisition of DWI sequences in a dedicated MRI protocol.

Two- versus three-dimensional dual gradient-echo MRI of the liver: a technical comparison.

OBJECTIVE: To compare 2D spoiled dual gradient-echo (SPGR-DE) and 3D SPGR-DE with fat and water separation for the assessment of focal and diffuse fatty infiltration of the liver. METHODS: A total of 227 consecutive patients (141 men; 56 ± 14 years) underwent clinically indicated liver MRI at 1.5 T including multiple-breath-hold 2D SPGR-DE and single-breath-hold 3D SPGR-DE with automatic reconstruction of fat-only images. Two readers assessed the image quality and number of fat-containing liver lesions on 2D and 3D in- and opposed-phase (IP/OP) images. Liver fat content (LFC) was quantified in 138 patients without chronic liver disease from 2D, 3D IP/OP, and 3D fat-only images. RESULTS: Mean durations of 3D and 2D SPGR-DE acquisitions were 23.7 ± 2.9 and 97.2 ± 9.1 s respectively. The quality of all 2D and 3D images was rated diagnostically. Three-dimensional SPGR-DE revealed significantly more breathing artefacts resulting in lower image quality (P < 0.001); 2D and 3D IP/OP showed a similar detection rate of fat-containing lesions (P = 0.334) and similar LFC estimations (mean: +0.4 %; P = 0.048). LFC estimations based on 3D fat-only images showed significantly higher values (mean: 2.7 % + 3.5 %) than those from 2D and 3D IP/OP images (P < 0.001). CONCLUSION: Three dimensional SPGR-DE performs as well as 2D SPGR-DE for the assessment of focal and diffuse fatty infiltration of liver parenchyma. The 3D SPGR-DE sequence used was quicker but more susceptible to breathing artefacts. Significantly higher LFC values are derived from 3D fat-only images than from 2D or 3D IP/OP images.

Performance of unenhanced respiratory-gated 3D SSFP MRA to depict hepatic and visceral artery anatomy and variants.

OBJECTIVES: To prospectively evaluate the performance of unenhanced respiratory-gated magnetization-prepared 3D-SSFP inversion recovery MRA (unenhanced-MRA) to depict hepatic and visceral artery anatomy and variants in comparison to contrast-enhanced dynamic gradient-echo MRI (CE-MRI) and to digital subtraction angiography (DSA). METHODS: Eighty-four patients (55.6±12.4 years) were imaged with CE-MRI (TR/TE 3.5/1.7ms, TI 1.7ms, flip-angle 15°) and unenhanced-MRA (TR/TE 4.4/2.2ms, TI 200ms, flip-angle 90°). Two independent readers assessed image quality of hepatic and visceral arteries on a 4-point-scale. Vessel contrast was measured by a third reader. In 28 patients arterial anatomy was compared to DSA. RESULTS: Interobserver agreement regarding image quality was good for CE-MRI (κ=0.77) and excellent for unenhanced-MRA (κ=0.83). Unenhanced-MRA yielded diagnostic image quality in 71.6% of all vessels, whereas CE-MRI provided diagnostic image quality in 90.6% (p<0.001). Vessel-based image quality was significantly superior for all vessels at CE-MRI compared to unenhanced-MRA (p<0.01). Vessel contrast was similar among both sequences (p=0.15). Compared to DSA, CE-MRI and unenhanced-MRA yielded equal accuracy of 92.9-96.4% for depiction of hepatic and visceral artery variants (p=0.93). CONCLUSIONS: Unenhanced-MRA provides diagnostic image quality in 72% of hepatic and visceral arteries with no significant difference in vessel contrast and similar accuracy to CE-MRI for depiction of hepatic and visceral anatomy.

Feasibility of semiquantitative liver perfusion assessment by ferucarbotran bolus injection in double-contrast hepatic MRI.

PURPOSE: To evaluate the feasibility of semiquantitative measurement of liver perfusion from analysis of ferucarbotran induced signal-dynamics in double-contrast liver MR-imaging (DC-MRI). MATERIALS AND METHODS: In total 31 patients (21 men; 58 ± 10 years) including 18 patients with biopsy proven liver cirrhosis prospectively underwent clinically indicated DC-MRI at 1.5 Tesla (T) with dynamic T2-weighted gradient-echo imaging after ferucarbotran bolus injection. Breathing artefacts in tissue and input time curves were reduced by Savitzky-Golay-filtering and semiquantitative perfusion maps were calculated using a model free approach. Hepatic blood flow index (HBFI) and splenic blood flow index (SBFI) were determined by normalization of arbitrary perfusion values to the perfusion of the erector spinae muscle resulting in a semiquantitative perfusion measure. RESULTS: In 30 of 31 patients the evaluated protocol could successfully be applied. Mean HBF was 7.7 ± 2.46 (range, 4.6-12.8) and mean SBF was 13.20 ± 2.57 (range, 8.5-17.8). A significantly lower total HBF was seen in patients with cirrhotic livers as compared to patients with noncirrhotic livers (P < 0.05). In contrast, similar SBF was observed in cirrhotic and noncirrhotic patients (P = 0.11). CONCLUSION: Capturing the signal dynamics during bolus injection of ferucarbotran in DC-MRI of the liver allows for semiquantitative assessment of hepatic perfusion that may be helpful for a more precise characterisation of liver cirrhosis and focal liver lesions.

A decision aid to rule out pneumonia and reduce unnecessary prescriptions of antibiotics in primary care patients with cough and fever.

BACKGROUND: Physicians fear missing cases of pneumonia and treat many patients with signs of respiratory infection unnecessarily with antibiotics. This is an avoidable cause for the increasing worldwide problem of antibiotic resistance. We developed a user-friendly decision aid to rule out pneumonia and thus reduce the rate of needless prescriptions of antibiotics. METHODS: This was a prospective cohort study in which we enrolled patients older than 18 years with a new or worsened cough and fever without serious co-morbidities. Physicians recorded results of a standardized medical history and physical examination. C-reactive protein was measured and chest radiographs were obtained. We used Classification and Regression Trees to derive the decision tool. RESULTS: A total of 621 consenting eligible patients were studied, 598 were attending a primary care facility, were 48 years on average and 50% were male. Radiographic signs for pneumonia were present in 127 (20.5%) of patients. Antibiotics were prescribed to 234 (48.3%) of patients without pneumonia. In patients with C-reactive protein values below 10 µg/ml or patients presenting with C-reactive protein between 11 and 50 µg/ml, but without dyspnoea and daily fever, pneumonia can be ruled out. By applying this rule in clinical practice antibiotic prescription could be reduced by 9.1% (95% confidence interval (CI): 6.4 to 11.8). CONCLUSIONS: Following validation and confirmation in new patient samples, this tool could help rule out pneumonia and be used to reduce unnecessary antibiotic prescriptions in patients presenting with cough and fever in primary care. The algorithm might be especially useful in those instances where taking a medical history and physical examination alone are inconclusive for ruling out pneumonia.

Pulmonary Kaposi's sarcoma after heart transplantation: a case report.

INTRODUCTION: Kaposi's sarcomas have been associated with different conditions of immunosuppression and are also known to be a typical complication of solid organ transplantations. CASE PRESENTATION: We report the case of a 65-year-old Turkish man with a history of heart transplantation 10 months ago who presented for clarification of his dyspnea. The patient had a known history of chronic obstructive pulmonary disease and a smoking history of 40 pack years. Radiologically, three progressively growing intra-pulmonary nodules were detected. The histology was diagnostic for a Kaposi's sarcoma. Visceral and especially primary intra-pulmonary Kaposi's sarcomas are very rare and have been described to have a rather unfavorable prognosis. CONCLUSIONS: Even with a history suggestive for conventional lung cancer, Kaposi's sarcomas should be considered in patients after transplantation of solid organs. It should be noted that in a minority of cases this tumor exists in the absence of the typical cutaneous lesions.