Jochen Gaa

Preliminary results for characterization of pelvic lymph nodes in patients with prostate cancer by diffusion-weighted MR-imaging.

Objectives:In this retrospective feasibility study diffusion-weighted magnetic resonance imaging (DWI) was evaluated as a potential tool for characterization of pelvic lymph nodes in patients with prostate cancer. Methods and Materials:Twenty-nine patients with prostate cancer underwent DWI of the pelvis at 1.5T by a non breath-hold SSEPI sequence using a body phased array coil with b values of 50, 300, and 600 s/mm2 and an additional T2-weighted sequence. A total of 118 lymph nodes (>6 mm short axis) were analyzed by measuring the ADC-value with a polygon region of interest. Feasibility for ADC-measurement was assessed by comparing the ADC-value from the automatically created ADC-map (ADCMR_unit) with a manually calculated ACD-value (ADCcalculated) and by using a linear-regression model for comparison with size and standard deviation of the ADC-value. Diagnostic performance was estimated by receiver operator characteristic analysis using histologic and/or clinical follow-up as standard of reference. Results:ADCMR_unit and ADCcalculated showed a high correlation (r = 0.8999) with a mean percentual deviation of 6.33%. There was a highly significant difference between the mean ADC-value (×10−3 mm2/s) of malignant (1.07 ± 0.23) versus benign (1.54 ± 0.25) lymph nodes, even in subgroup analysis for lymph nodes smaller versus larger than 10 mm. Receiver operator characteristic-analysis showed a good accuracy of the ADC-value (85.6% [101/118]; sensitivity: 86.0% [43/50]; specificity: 85.3% [53/68]) for differentiation of malignant and benign lymph nodes at a cutoff 1.30 × 10−3 mm2/s. This was superior to a size-based analysis at a cutoff of 8 mm (accuracy: 66.1% [78/118]; sensitivity: 82.0% [41/50]; specificity: 54.4% [37/68]; P < 0.01). Conclusions:DWI has the potential of being an accurate technique for analysis of pelvic lymph nodes. Moreover, our preliminary results suggest that the ADC-value might perform significantly superior to size criteria to discriminate between benign and malignant lymph nodes.

Diagnosis of Hepatic Metastasis: Comparison of Respiration-Triggered Diffusion-Weighted Echo-Planar MRI and Five T2-Weighted Turbo Spin-Echo Sequences

OBJECTIVE The purpose of this study was to compare the value of respiration-triggered diffusion-weighted (DW) single-shot echo-planar MRI (EPI) and five variants of T2-weighted turbo spin-echo (TSE) sequences in the diagnosis of hepatic metastasis. MATERIALS AND METHODS Fifty-two patients with extrahepatic primary malignant tumors underwent 1.5-T MRI that included DW EPI and the following variants of T2-weighted TSE techniques: breath-hold fat-suppressed HASTE, breath-hold fat-supressed TSE, respiration-triggered fat-suppressed TSE, breath-hold STIR, and respiration-triggered STIR. Images were reviewed independently by two blinded observers who used a 5-point confidence scale to identify lesions. Results were correlated with surgical and histopathologic findings and follow-up imaging findings. The accuracy of each technique was measured with free-response receiver operating characteristic analysis. RESULTS A total of 118 hepatic metastatic lesions (mean diameter, 12.8 mm; range, 3-84 mm) were evaluated. Accuracy values were higher (p < 0.001) with DW EPI (0.91-0.92) than with the T2-weighted TSE techniques (0.47-0.67). Imaging with the HASTE sequence (0.47-0.52) was less accurate (p < 0.05) than imaging with the breath-hold TSE, breath-hold STIR, respiration-triggered TSE, and respiration-triggered STIR sequences (0.59-0.67). Sensitivity was higher (p < 0.001) with DW EPI (0.88-0.91) than with T2-weighted TSE techniques (0.45-0.62). For small (< or = 10 mm) metastatic lesions only, the differences in sensitivity between DW EPI (0.85) and T2-weighted TSE techniques (0.26-0.44) were even more pronounced. CONCLUSION DW EPI was more sensitive and more accurate than imaging with T2-weighted TSE techniques. Because of the black-blood effect on vessels and low susceptibility to motion artifacts, DW EPI was particularly useful for the detection of small (< or = 10 mm) metastatic lesions.

MR imaging of pulmonary parenchyma with a half-Fourier single-shot turbo spin-echo (HASTE) sequence

OBJECTIVE To evaluate the utility of a half-Fourier single-shot turbo spin-echo sequence (HASTE) at depicting lung parenchyma and lung pathology. METHODS AND PATIENTS A HASTE sequence was applied to five normal volunteers and 20 patients with various pulmonary disorders to depict the lung parenchyma. Images were acquired with ECG-triggering and breath-holding. In three volunteers, signal intensity measurements from lung parenchyma were performed using four sequences: (a) HASTE; (b) conventional spin echo; (c) fast spin echo; and (d) gradient echo. T2 maps were produced using the HASTE acquisition. RESULTS Minimal respiratory or cardiac motion artifacts were observed. The signal-to-noise ratios from lung parenchyma were 27.8 +/- 5.4, 22.0 +/- 3.0, 15.3 +/- 0.9, and 6.0 +/- 1.9 for HASTE, spin-echo, fast spin-echo, and gradient echo sequences, respectively. The scan time for HASTE was 302 ms for each slice. The T2 values in the right lung and the left lung were 61.2 +/- 4.1 and 79.1 +/- 8.9 ms in systole and 92.6 +/- 5.8 and 97.5 +/- 12.2 ms in diastole, respectively (P < 0.05 diastole versus systole). The HASTE sequence demonstrated clearly various pulmonary disorders, including lung cancer, hilar lymphadenopathy, metastatic pulmonary nodules as small as 3 mm, pulmonary hemorrhage, pulmonary edema and bronchial wall thickening in bronchiectasis. CONCLUSION Our preliminary results indicate that the HASTE sequence provides a practical means for breath-hold MR imaging of lung parenchyma.

MR differentiation of phaeochromocytoma from other adrenal lesions based on qualitative analysis of T2 relaxation times

AIM To determine the diagnostic accuracy of MR imaging in differentiating phaeochromocytoma from other adrenal lesions. MATERIALS AND METHODS Sixty-seven adrenal masses (65 patients) including 17 phaeochromocytomas were imaged using T2-weighted pulse sequences on 0.6 T and 1.5 T GE MR units. The adrenal lesions were qualitatively assessed by three observers and divided into three categories (benign adenomas, malignant lesions and phaeochromocytomas) based on lesion signal intensity relative to liver and cerebrospinal fluid. RESULTS Eleven phaeochromocytomas (65%) were correctly identified while the remaining six (35%) were misclassified, five as malignant lesions and one as a benign adenoma, because of atypical low signal intensity on T2-weighted MR images. Conversely, six non-phaeochromocytomas (three benign adenomas, two adrenal carcinomas and one metastasis) were wrongly classified as phaeochromocytomas because of very high lesion signal intensity. The sensitivity of MR imaging for diagnosing phaeochromocytoma was 64.7%, specificity 88.0%, positive predictive value 64.7% and negative predictive value 88.0%. CONCLUSION There is considerable overlap between the MR appearance of phaeochromocytoma and other adrenal lesions. A phaeochromocytoma cannot be excluded on the basis of a lack of high signal intensity on T2-weighted MR imaging.

Staging of colon carcinoma using water enema CT.

Objective To determine the accuracy of water enema CT (WECT) for staging colon carcinoma. Materials and Methods Thirty patients with colon cancer, diagnosed by barium enema and/or colonoscopy, underwent preoperative WECT. Dynamic contrast enhanced CT studies were performed after rectal administration of 2 L lukewarm tap water. Images were prospectively analyzed for depth of tumor invasion, nodal involvement, and distant metastases by investigators blinded to the results of barium enema and colonoscopy. Surgical/pathologic proof was obtained in all cases Results Using WECT, 23 of 30 patients were correctly staged. Correct staging occurred in 2 of 2 patients with Stage A, 3 of 3 patients with Stage B1, 6 of 9 patients with Stage B2, 1 of 2 patients with Stage C1, 5 of 8 patients with Stage C2, and 6 of 6 patients with Stage D tumors. Of the patients incorrectly staged, 4 were understaged and 3 were overstaged; all were due to errors in predicting lymph node involvement. Sensitivity and specificity for evaluating nodal involvement were 60 and 79%. respectively. Conclusions Water enema CT allows for accurate depiction and staging of colon carcinoma. Aqueous distention of the colon avoids artifacts seen with positive contrast agents yet allows accurate evaluation of the bowel wall and pericolonic structures.

Noninvasive perfusion imaging of human brain tumors with EPISTAR.

A total of 17 patients with histologically proven diagnoses of low-grade astrocytoma (n = 4), high-grade astrocytoma (n = 8), lymphoma (n = 3), and meningioma (n = 2) were examined by using EPISTAR MR imaging. Meningiomas had the highest EPISTAR tumor/white matter contrast and low-grade astrocytomas and lymphomas the lowest. High-grade astrocytomas demonstrated elevated EPISTAR signal with marked regional heterogeneity. There was agreement between tumor vascularity by SPECT and EPISTAR in the five cases where both were done. Our results show that tumor vascularity can be assessed qualitatively by using EPISTAR without the need for contrast medium injection.

Advanced Hemodynamic Monitoring before and after Transjugular Intrahepatic Portosystemic Shunt: Implications for Selection of Patients—A Prospective Study

PURPOSE To investigate immediate and short-term effects of transjugular intrahepatic portosystemic shunt (TIPS) on cardiocirculatory, hepatic, and renal function and characterize predictors for TIPS outcome in terms of organ function after TIPS. MATERIALS AND METHODS This prospective study was approved by the ethics committee at a university hospital and was conducted in a medical intensive care unit. Informed consent was obtained. Twenty patients with indication for TIPS were enrolled. Monitoring of hemodynamic and hepatic function (transpulmonary thermodilution, indocyanine green plasma disappearance rate [ICG-PDR]) was performed. Biochemical markers of organ function were obtained. Statistical analysis (Wilcoxon test, Spearman correlation, multivariate linear regression analysis, receiver operating characteristic [ROC] analysis) was performed. RESULTS After TIPS, central venous pressure (median, 11 vs 15 cm H(2)O; P < .001), cardiac index (3.4 vs 3.8 L/min/m(2); P = .001), and global end-diastolic volume index (GEDVI) (726 vs 775 mL/m(2); P = .003) increased significantly. Portosystemic pressure gradient (28 vs 11 cm H(2)O; P < .001) and systemic vascular resistance index (1610 vs 1384 dyn · sec · cm(-5) · m(2); P = .015) decreased significantly. Creatinine (1.1 vs 1.1 mg/dL; P = .008) and blood urea nitrogen (BUN) (27 vs 21 mg/dL; P = .006) decreased significantly. Bilirubin (1.8 vs 2.2 mg/dL; P = .032) and international normalized ratio (1.4 vs 1.5; P = .022) increased significantly. ICG-PDR significantly deteriorated after TIPS (P = .006). Higher baseline creatinine was independently associated with a decrease in creatinine after TIPS (R = 0.816, P < .001). ROC analysis identified baseline BUN (P = .026, area under ROC curve [AUC] = 0.818), cystatin C (P = .033, AUC = 0.805), and creatinine (P = .052, AUC = 0.779) as predictors of a decrease in creatinine of 0.5 mg/dL or greater and/or 25% or greater. An increase in bilirubin of 1 mg/dL or greater 1 week after TIPS was significantly associated with high baseline BUN (P = .007, AUC = 0.893) and high central venous pressure (P = .040, AUC = 0.800). Lower baseline alanine aminotransferase (P = .002, AUC = 1.000) and cardiac power index · GEDVI (P = .005, AUC = 0.960) predicted favorable TIPS outcome (creatinine decrease of ≥ 0.2 mg/dL without model for end-stage liver disease score increase of more than one point). CONCLUSION Patients with renal insufficiency, compensated hepatocellular function, decreased cardiac preload, and decreased cardiac performance benefit most from TIPS.

Case report: Haemorrhagic hepatic adenoma — MR features

Hepatic adenomas are incidentally detected with increasing frequency after imaging the abdomen for unrelated pathology. We report the CT and MR features of an asymptomatic hepatic adenoma with evidence of subclinical intratumoral haemorrhage.

An Unusual Cause of Right-Sided Pleural Effusion

DIS 5.2.0 DTD YGAST59002_proof 23 May 2014 7:22 pm ce Ga 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 Question: A 78-yearold man with an unremarkable past medical history presented in the emergency department with mild dyspnea, recurrent episodes of fever, diffuse abdominal pain, and a 10-kgweight loss within the last 6 months. After admission, abdominal ultrasonography revealed a large, cystic lesion in the right liver lobe. A rightsided pleural effusion was seen on chest radiography (not shown). Routine laboratory findings were normal except for elevated C-reactive protein (3.6 mg/dL; normal, <1.0 mg/dL) and slightly elevated gammaglutamyltransferase (68 IU/L; normal, <55 IU/L). Computed tomography showed rightsided pleural effusion (Figure A, arrow) and a large, irregularly shaped cystic lesion with peripheral calcifications in the right liver lobe (Figure B, arrow). On 105 106 107 108 109 110 F-18 fluorodeoxyglucose positron emission tomography (PET)/computed tomography (CT), the liver lesion appeared with an increased peripheral activity (Figure C, arrows) and a large hypometabolic region centrally. The hypermetabolic area extended cranially where it reached the diaphragm (Figure D, arrows). What is the diagnosis? Look on page 000 for the answer and see the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI.

Gonadal Vein Recruitment in Renal Cell Carcinoma: Incidence, Pathogenesis and Clinical Significance

OBJECTIVE Gonadal vein recruitment by collateral veins in patients with renal cell carcinoma is not routinely searched for during abdominal computed tomography. We performed a retrospective view to determine the incidence of gonadal vein recruitment for collateral venous drainage in patients with renal cell carcinoma and we discuss its potential importance. PATIENTS AND METHODS Abdominal CT examinations were available for 58 of 95 patients with renal cell carcinoma identified during a 3-year-period. The presence of collateral veins and recruitment of the ipsilateral gonadal vein was recorded and correlated with the estimated blood loss at surgery. RESULTS Eighteen of 58 tumours were small (less than 5 cm). Multiple (greater than three) collateral renal capsular veins were noted in 26 of 58 patients and few (less than three) were noted in 11. Recruitment of the gonadal vein (range 4-18 mm, mean 8 mm) was seen in 18 of 58 patients (31%) who all had multiple collaterals. Gonadal vein recruitment was only seen in patients with tumours greater than 5 cm. Mean estimated blood loss at surgery was significantly different (P < 0.01) in 18 of 58 patients (mean, 1078 ml) with gonadal vein recruitment compared to 40 of 58 patients (mean 304 ml) without distinct visualization of the gonadal vein and compared to 22 of 40 patients with large tumours (mean 368 ml). CONCLUSION Gonadal vein recruitment signifies well-developed arteriovenous shunting and high flow collateral venous drainage pathways and may be used as an index of tumour vascularity. This finding may have clinical potential in triaging patients toward pre-operative renal embolization.