Peter Hallscheidt

Primary malignant hepatic epithelioid hemangioendothelioma : A comprehensive review of the literature with emphasis on the surgical therapy

Malignant hepatic epithelioid hemangioendothelioma (HEH) is a rare malignant tumor of vascular origin with unknown etiology and a variable natural course. The authors present a comprehensive review of the literature on HEH with a focus on clinical outcome after different therapeutic strategies. All published series on patients with HEH (n = 434 patients) were analyzed from the first description in 1984 to the current literature. The reviewed parameters included demographic data, clinical manifestations, therapeutic modalities, and clinical outcome. The mean age of patients with HEH was 41.7 years, and the male‐to‐female ratio was 2:3. The most common clinical manifestations were right upper quadrant pain, hepatomegaly, and weight loss. Most patients presented with multifocal tumor that involved both lobes of the liver. Lung, peritoneum, lymph nodes, and bone were the most common sites of extrahepatic involvement at the time of diagnosis. The most common management has been liver transplantation (LTx) (44.8% of patients), followed by no treatment (24.8% of patients), chemotherapy or radiotherapy (21% of patients), and liver resection (LRx) (9.4% of patients). The 1‐year and 5‐year patient survival rates were 96% and 54.5%, respectively, after LTx; 39.3% and 4.5%, respectively, after no treatment, 73.3% and 30%, respectively, after chemotherapy or radiotherapy; and 100% and 75%, respectively, after LRx. LRx has been the treatment of choice in patients with resectable HEH. However, LTx has been proposed as the treatment of choice because of the hepatic multicentricity of HEH. In addition, LTx is an acceptable option for patients who have HEH with extrahepatic manifestation. Highly selected patients may be able to undergo living‐donor LTx, preserving the donor pool. The role of different adjuvant therapies for patients with HEH remains to be determined. Cancer 2006.

Preoperative Staging of Renal Cell Carcinoma With Inferior Vena Cava Thrombus Using Multidetector Ct and Mri: Prospective Study With Histopathological Correlation

Objective: To evaluate the accuracy of multidetector computed tomography (CT) and magnetic resonance imaging (MRI) in staging and estimating renal carcinomas with caval thrombus. Methods: Initially, 23 patients with suspected caval thrombi were admitted into this prospective study. Triphasic CT imaging was performed using a multidetector CT with a reconstructed slice thickness of 2 mm. 3D CT reconstructions were used to improve surgical planning. MRI protocol included: a transversal T1-weighted GE sequence with and without Gd-DTPA, a transversal T2-weighted respiratory-gated TSE, and a coronal T1-weighted GE sequence with Gd-DTPA and fat saturation. In addition, a multiphase 3D angiography was performed after Gd-DTPA injection. Patients were divided into 3 groups: caval thrombus below the insertion of the hepatic veins, within the intrahepatic vena cava, and intra-atrial extension. The results the tumor thrombus extension and staging results of 2 independent readers were correlated with surgical and histopathological staging. Results: Of the 23 patients admitted, CT and MR scans of 14/13 patients respectively were correlated with histopathological workup. CT thrombus detection sensitivity and specificity for both readers was 0.93 and 0.8 respectively. MRI sensitivity and specificity for both readers was 1.0/0.85 and 0.75. Readers I and II evaluated the uppermost extension of the cranial tumor thrombus by both CT and MRI. CT and MR accuracy was 78% and 72%, 88% and 76% respectively. Conclusion: In cases of a suspected tumor thrombus, MRI and multidetector CT imaging showed similar staging results. Consequently, these staging modalities can be used to assess the extension of the tumor thrombus.

Investigation of renal lesions by diffusion-weighted magnetic resonance imaging applying intravoxel incoherent motion-derived parameters—Initial experience

PURPOSE Usefulness of biexponentially fitted signal attenuation at different b-values for differentiating the histological characteristics of renal tumors. MATERIALS AND METHODS A total of 26 patients with 28 renal masses (histologically proven: 20 clear cell renal cell carcinomas [ccRCC], three transitional cell carcinomas, two oncocytomas, and one papillary RCC) and 30 volunteers with healthy kidneys were examined at 1.5 Tesla using an echo-planar DWI sequence. Using the IVIM model, we calculated the perfusion fraction f and the diffusion coefficient D. Furthermore, the ADC was obtained. These tumor parameters were compared to healthy renal tissue nonparametrically, and a receiver operating characteristic (ROC) analysis was performed. RESULTS Healthy renal parenchyma showed higher ADC and D values (p<0.001) than ccRCC (ADC 1.95±0.10 [SD] μm2/ms, f 18.32±2.52%, and D 1.88±0.11 μm2/ms versus ADC 1.45±0.38 μm2/ms, f 18.59±6.16%, and D 1.34±0.38 μm2/ms). When detecting malignancies the area under the curve for D was higher than for ADC. The f values for ccRCC were higher (p<0.001) than for non-ccRCC (ADC 1.52±0.47 μm2/ms, f 8.44±1.24%, and D 1.30±0.18 μm2/ms). Both f and D correlated with ccRCC grading. CONCLUSION IVIM imaging is able to provide reliable diffusion values in the human kidney and may enhance the accuracy of tumor diagnosis. The D value was the best parameter to distinguish renal tumors from healthy renal tissue. The f value is promising for determining the histological subgroups.

Diagnostic accuracy of staging renal cell carcinomas using multidetector-row computed tomography and magnetic resonance imaging: a prospective study with histopathologic correlation.

Objective: The aim of this prospective study is to compare the diagnostic accuracy of multidetector-row computed tomography (CT) and magnetic resonance imaging (MRI) in tumor staging of renal cell carcinomas. Methods: In a prospective study, 82 renal cell carcinomas were assessed for tumor staging before surgery using multidetector-row CT and MRI, the results of which were then correlated to histopathologic staging. Triphasic CT (noncontrast, arterial phase, and parenchymal phase) imaging was performed using multidetector-row CT with a reconstructed slice thickness of 2 mm. In MRI, a transverse T1-weighted gradient echo sequence with and without administration of Gd-DTPA, a transverse T2-weighted respiratory-gated turbo spin echo (TSE) sequence, and a coronal T1-weighted gradient echo sequence with Gd-DTPA were used. In addition, multiphasic 3-dimensional angiography after Gd-DTPA injection and a transverse T1-weighted fat-suppression sequence were performed. Results: With MRI, readers 1 and 2 correctly staged 71 and 64 tumors (overall accuracy of 0.87 and 0.78, respectively) and achieved Mantel-Haenszel χ2 values of 66 and 63 (P < 0.0001). Computed tomography allowed correct staging of 68 and 66 tumors (readers 1 and 2, overall accuracy of 0.83 and 0.80, respectively) with Mantel-Haenszel χ2 values of 54 and 54 for CT staging (P < 0.0001). No statistically significant difference between overall accuracy was found in the χ2 test (P > 0.15). Conclusion: Magnetic resonance imaging and multidetector-row CT with its multiplanar reconstruction capabilities achieve similar accuracy in tumor staging of renal cell carcinomas.

Vessel Fractions in Tumor Xenografts Depicted by Flow-or Contrast-Sensitive Three-Dimensional High-Frequency Doppler Ultrasound Respond Differently to Antiangiogenic Treatment

High-frequency volumetric Power Doppler ultrasound (HF-VPDU) captures flow-dependent signals in blood vessels and can be used to assess antiangiogenic therapy effects in rodent tumors. However, the sensitivity is limited to vessels larger than capillaries. Contrast-enhanced HF-VPDU reveals all perfused vessels by assessing stimulated acoustic emissions from disintegrating microbubbles. Thus, we investigated whether flow-sensitive and contrast-enhanced HF-VPDU can depict different vessel fractions and assess their early response to antiangiogenic therapy. Mice with A431 tumors were scanned before and after administration of polybutylcyanoacrylate microbubbles by HF-VPDU. Animals received either antiangiogenic treatment (SU11248) or a control substance and were imaged repeatedly over 9 days. At each time point, tumors were removed for immunohistochemical analysis. During growth of untreated tumors, vascularization decreased correspondingly on flow-sensitive and contrast-enhanced scans. Treated tumors showed a significantly (P < 0.05) stronger decline in vascularization than controls, which was more pronounced in contrast-enhanced scans. Surprisingly, whereas vascularization remained low in contrast-enhanced scans, flow-sensitive ultrasound indicated a reincrease after day 6 with a higher vascularization than the controls at day 9. Histologic evaluation indicated that immature vessels degraded markedly on therapy, whereas large mature vessels on the tumor periphery were more therapy resistant and drew closer due to tumor shrinkage. In conclusion, contrast-enhanced HF-VPDU and flow-sensitive HF-VPDU are both capable of assessing the effects of antiangiogenic therapy. Because contrast-sensitive ultrasound is more sensitive for small immature vessels and flow-sensitive ultrasound mostly captures large vessels at the tumor periphery, the combination of both methods can provide evidence of vascular maturity in tumors.

Metastasis to the pancreas: characterization by morphology and contrast enhancement features on CT and MRI.

Aims: To investigate the characteristics of metastasis to the pancreas using computed tomography (CT) and magnetic resonance imaging (MRI). Methods: Twenty-two patients with metastases to the pancreas were examined preoperatively by MRI (7/22) and/or multidetector CT (15/22). Pre- and post-contrast images were acquired and morphology, size, and contrast enhancement of the tumor analyzed. Subsequently, all patients underwent surgery, and the histopathologic findings were compared with the imaging results. Results: In 22 patients, a total of 29 metastases were found on CT and MRI. These metastases originated from renal cell carcinomas (RCC; 22/29), colorectal carcinoma (3/29), and other malignancies (4/29). The metastases differed not in size or location, but in their contrast enhancement characteristics. RCC metastases had either intense homogeneous enhancement (in small lesions) or rim enhancement (in large lesions). Outer regions of colorectal metastases showed no difference from normal pancreatic tissue, whereas the inner area showed hypo-enhancement due to central necrosis. Conclusion: Imaging features of metastases from RCC point to their primary origin. While they can be distinguished from primary adenocarcinoma of the pancreas, differentiation from endocrine carcinoma might be difficult. Differentiation of colorectal carcinoma remains to be investigated on larger numbers of cases.

MR coil design for simultaneous tip tracking and curvature delineation of a catheter

In active catheter tracking, small RF coils are attached to the catheter for localization. For interactive catheter steering at vessel branchings, it is necessary to visualize not only a single point near the catheter tip but also the entire shape and orientation of the catheters distal end. Therefore, a 35‐mm‐long twisted‐pair RF coil was added to a 5 French intravascular catheter with a single tip‐tracking coil. With the use of small nonmagnetic electronic components at the catheter tip, and a special switching circuitry outside the catheter, the coil assembly could be operated in two different modes. During MRI, the tip‐tracking coil was detuned so that the MR signal was received by the visualization coil only. During tracking, detuning was switched off and the MR signal was predominantly received by the more sensitive tracking coil. The catheter was used in combination with a MR pulse sequence with automatic slice positioning so that the current imaging slice was always placed at the position of the catheter tip. Phantom and animal experiments showed that the catheter tip is better visualized with the combined approach than with a tracking coil alone. Magn Reson Med 52:214–218, 2004.

Imaging of female pelvic malignancies regarding MRI, CT, and PET/CT

PurposeTo compose diagnostic standard operating procedures for both clinical and imaging assessment for vulvar and vaginal cancer, for vaginal sarcoma, and for ovarian cancer.MethodsThe literature was reviewed for diagnosing the above mentioned malignancies in the female pelvis. Special focus herein lies in tumor representation in MRI, followed by the evaluation of CT and PET/CT for this topic.ConclusionMRI is a useful additional diagnostic complement but by no means replaces established methods of gynecologic diagnostics and ultrasound. In fact, MRI is only implemented in the guidelines for vulvar cancer. According to the current literature, CT is still the cross-sectional imaging modality of choice for evaluating ovarian cancer. PET/CT appears to have advantages for staging and follow-up in sarcomas and cancers of the ovaries.ZusammenfassungZielÜbersicht der aktuellen bildgebenden Diagnostik des Vulva- und des Vaginalkarzinoms, des Vaginalsarkoms und des Ovarialkarzinoms.MethodeDurchsicht der Fachliteratur und Erstellung einer Übersicht der Diagnostik weiblicher Beckentumoren mittels MRT und CT sowie PET/CT mit Bildbeispielen unter Einschluss der tumorbezogenen Staging-Kriterien sowie empfohlenen MRT-Sequenzen.SchlussfolgerungDie MRT ist neben der gynäkologischen Untersuchung und dem Ultraschall eine nützliche bildgebende Ergänzung in der Diagnostik. Allerdings ist die MRT bisher nur in den Leitlinien des Vulvakarzinoms verankert. Für die Diagnostik des Ovarialkarzinoms ist die CT weiterhin Schnittbildgebung der Wahl. Die PET/CT scheint vorteilhaft beim Staging und beim Follow-up von Sarkomen und Ovarialkarzinomen zu sein.

Pharmacodynamics of streptavidin-coated cyanoacrylate microbubbles designed for molecular ultrasound imaging

Objectives:To assess the pharmacodynamic behavior of cyanoacrylate, streptavidin-coated microbubbles (MBs) and to investigate their suitability for molecular ultrasound imaging. Materials and Methods:Biodistribution of MBs was analyzed in tumor-bearing mice using &ggr;-counting, immunohistochemistry, flow cytometry, and ultrasound. Further, vascular endothelial growth factor receptor 2-antibody coupled MBs were used to image tumor neovasculature. Results:After 1 minute >90% of MBs were cleared from the blood and pooled in the lungs, liver, and spleen. Subsequently, within 1 hour a decent reincrease of MB-concentration was observed in the blood. The remaining MBs were removed by liver and spleen macrophages. About 30% of the phagocytosed MBs were intact after 48 hours. Shell fragments were found in the kidneys only. No relevant MB-accumulation was observed in tumors. In contrast, vascular endothelial growth factor receptor 2-specific MBs accumulated significantly within the tumor vasculature (P < 0.05). Conclusions:The pharmacokinetic behavior of streptavidin-coated cyanoacrylate MBs has been studied. In this context, the low amount of MBs in tumors after >5 minutes is beneficial for specific targeting of angiogenesis.

Active catheter tracking using parallel MRI and real-time image reconstruction.

In this work active MR catheter tracking with automatic slice alignment was combined with an autocalibrated parallel imaging technique. Using an optimized generalized autocalibrating partially parallel acquisitions (GRAPPA) algorithm with an acceleration factor of 2, we were able to reduce the acquisition time per image by 34%. To accelerate real‐time GRAPPA image reconstruction, the coil sensitivities were updated only after slice reorientation. For a 2D trueFISP acquisition (160 × 256 matrix, 80% phase matrix, half Fourier acquisition, TR = 3.7 ms, GRAPPA factor = 2) real‐time image reconstruction was achieved with up to six imaging coils. In a single animal experiment the method was used to steer a catheter from the vena cava through the beating heart into the pulmonary vasculature at an image update rate of about five images per second. Under all slice orientations, parallel image reconstruction was accomplished with only minor image artifacts, and the increased temporal resolution provided a sharp delineation of intracardial structures, such as the papillary muscle. Magn Reson Med, 2006.