[Oncological imaging for therapy response assessment]. / Onkologische Bildgebung zur Beurteilung des Therapieansprechens.

This review illustrates different radiological methods for therapy response assessment in the field of oncological imaging. Unidimensional measurement of tumor size according to the response evaluation criteria in solid tumors (RECIST) is of utmost importance. The established RECIST definitions of changes in size are decisive for subdivision into the categories complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD), which are generally accepted as the concise characterization for therapy response. Problems with size-dependent response assessment occur particularly in targeted therapy and by phenomena, such as pseudoprogression. Several variants of functional imaging and their role in cancer imaging regarding practical requests are introduced.

[Whole-body diffusion-weighted imaging in oncology: technical aspects and practical relevance]. / Ganzkörperdiffusionsbildgebung in der Onkologie: Technische Aspekte und praktischer Stellenwert.

This review illustrates the relevance of whole-body diffusion-weighted imaging (WB-DWI) in the field of oncological imaging. WB-DWI is an alternative method to positron-emission tomography/computed tomography (PET/CT) due to the lack of radiation and lower examination costs. Technical aspects of WB-DWI and the current role of the method in cancer imaging regarding practical requirements in oncology are presented.

Suitability of semi-automated tumor response assessment of liver metastases using a dedicated software package.

PURPOSE: To evaluate the suitability of semi-automated compared to manual tumor response assessment (TRA) of liver metastases. MATERIALS AND METHODS: In total, 32 patients with colorectal cancer and liver metastases were followed by an average of 2.8 contrast-enhanced CT scans. Two observers (O 1, O 2) measured the longest diameter (LD) of 269 liver metastases manually and semi-automatically using software installed as thin-client on a PACS workstation (LMS-Liver, MEDIAN Technologies). LD and TRA ("progressive", "stable", "partial remission") were performed according to RECIST (Response Evaluation Criteria in Solid Tumors) and analyzed for between-method, interobserver and intraobserver variability. The time needed for evaluation was compared for both methods. RESULTS: All measurements correlated excellently (r>or=0.96). Intraobserver (semi-automated), interobserver (manual) and between-method differences (by O 1) in LD of 1.4+/-2.6 mm, 1.9+/-1.9 mm and 2.1+/-2.0 mm, respectively, were not significant. Interobserver (semi-automated) and between-method (by O 2) differences in LD of 3.0+/-3.0 mm and 2.6+/-2.0 mm, respectively, reflected a significant variability (p<0.01). The interobserver agreement in manual and semi-automated TRA was 91.4 %. The intraobserver agreement in semi-automated TRA was 84.5%. Between both methods a TRA agreement of 86.2% was obtained. Semi-automated evaluation (2.7 min) took slightly more time than manual evaluation (2.3 min). CONCLUSION: Semi-automated and manual evaluation of liver metastases yield comparable results in response assessments and require comparable effort.

[The relevance of magnetic resonance imaging (MRI) for the detection and exclusion of prostate cancer]. / Bedeutung der Magnetresonanztomographie (MRT) für Nachweis und Ausschluss des Prostatakarzinoms.

This review illustrates the relevance of magnetic resonance imaging (MRI) for the detection or exclusion of prostate cancer. The functional MR methods dynamic contrast-enhanced MRI (DCE-MRI), MR spectroscopy, and diffusion-weighted imaging (DWI) helped in recent years to establish MRI as the imaging method of choice for prostate cancer. Indications for MRI of the prostate regarding recent guidelines and new concepts of cancer therapy are introduced.

[Relevance of radiological imaging for lymph node surgery of urological tumors]. / Bedeutung der radiologischen Bildgebung für die Lymphknotenchirurgie urologischer Malignome.

This review illustrates the relevance of computed tomography (CT) and magnetic resonance imaging (MRI) for detecting or excluding lymph node metastases in urological malignancies. Although radiological assessment of lymph node metastases is well established in renal cell and testicular cancer, it is unreliable in prostate, bladder, and penile cancer. MR lymphography has shown promising results in these tumors, but because marketing authorization for the iron oxide contrast agent is lacking, it is not clinically applicable. Percutaneous CT-guided biopsy in the retroperitoneum and pelvis is introduced as an alternative in the histological exploration of suspicious lymph nodes.

[Diagnosis of an accessory liver lobe established by magnetic resonance imaging-guided core biopsy]. / Diagnose einer Nebenleber mittels Magnetresonanztomografie-gesteuerter Stanzbiopsie.

An accessory liver is a rare developmental anomaly. There are two subtypes: the accessory liver lobe (ALL), which is connected to the liver and the true ectopic liver. An accessory liver is usually of no clinical relevance in spite of the very rare cases in which torsion or other complications may cause serious problems. This anomaly should not be misinterpreted as a malignant tumour. We report the case of an accessory liver lobe, located below the left diaphragm, which was misdiagnosed as a metastasis of a known malignant melanoma. The diagnosis ALL was established by a biopsy under guidance of magnetic resonance tomography (MRT). In our opinion, an accessory liver and its appearance should be known, to include this entity in differential diagnosis of perihepatic masses.

Mid-term outcome of positron emission tomography/computed tomography-assisted radiofrequency ablation in primary and secondary liver tumours--a single-centre experience.

AIMS: To determine the mid-term results of percutaneous radiofrequency ablation (RFA) of malignant liver tumours when using FDG-positron emission tomography (FDG-PET)/computed tomography for tumour evaluation and follow-up. MATERIALS AND METHODS: Between January 2002 and June 2006, 55 patients (mean age 63 years) with 78 liver lesions (39 colorectal metastases, 39 hepatocellular carcinoma [HCC] nodules) were treated with RFA. All patients received PET/computed tomography before intervention. RFA was performed under computed tomography guidance with conscious sedation. Post-interventional PET/computed tomography was carried out in PET-positive patients 24h after the ablation and was repeated at 1, 3 and 6 months and every 6 months after the intervention. PET-negative patients received contrast-enhanced computed tomography at the same time points. The rate of local tumour progression (LTP) and survival rates were assessed for the whole patient population. RESULTS: The 78 lesions (mean size 2.3 cm, range 0.8-5 cm) were treated with 101 consecutive ablation procedures resulting in a technical success rate of 96%. The mean time of follow-up was 25+/-12 months. Thirty-five of 78 tumours (45%) developed LTP. At the end of follow-up, LTP was found in 22 patients (40%), with intra- and extrahepatic recurrence in 11 patients. Twenty-two patients remained free of hepatic tumours. The 1-, 2- and 3-year survival rates were 85, 74 and 58%, respectively. Tumour entity, lesion size and localisation were significant risk factors for LTP. CONCLUSIONS: Computed tomography-guided RFA of malignant liver tumours is effective, but shows a high rate of LTP. PET/computed tomography supports RFA by early identification of residual tumour or LTP.

[Liver biopsy under guidance of multislice computed tomography: comparison of 16G and 18G biopsy needles]. / Leberbiopsie mit Hilfe der Mehrschichtcomputertomographie : Vergleich zwischen 16-G- und 18-G-Biopsienadeln.

BACKGROUND: Percutaneous cutting needle biopsy of focal liver lesions under CT guidance has established itself as a standard method. The purpose of this study was to evaluate which diagnostic quality can be achieved under guidance of multislice CT (MSCT) and with the use of different needle sizes. METHODS: The data of 163 MSCT-guided core biopsies of focal liver lesions were evaluated. A 16G biopsy needle was used in 121 cases and an 18G needle in 42 cases. RESULTS: The sensitivity, specificity, and accuracy for all biopsies were 93.3, 100.0, and 94.5%. The corresponding values were 97.2, 100.0, and 97.5% for the 16G needle and 78.6, 100.0, and 85.7% for the 18G needle, respectively. A definite histological diagnosis could be obtained in 90.0% of the cases (16G 94.0%, 18G 75.8%). These differences were statistically highly significant. Bleeding complications were recognized in seven biopsies (4.3%). In one patient a fatal bleeding occurred after the biopsy. Median biopsy duration was 27 min. CONCLUSIONS: Core biopsy under MSCT guidance is a fast and very accurate method to obtain a histological diagnosis in focal liver lesions. The usage of a 16G needle in comparison to an 18G needle yielded a significantly higher rate of correct results with regard to differentiation between benign and malignant disease as well as establishing a definite histological diagnosis. For an accurate diagnosis of liver lesions a 16G needle is recommended. After biopsy, the patients have to be closely monitored.

[Comparison of unidimensional and bidimensional measurement to assess therapeutic response in the treatment of solid tumors]. / Vergleich uni- und bidimensionaler Messverfahren zur Beurteilung des Therapieansprechens bei der Behandlung solider Tumoren.

PURPOSE: In this prospective study we applied both the bidimensional WHO method and the unidimensional RECIST method in treatment follow-up of solid tumors. MATERIAL AND METHODS: Computed tomography was performed in 80 patients before and after one chemotherapy cycle: 20 patients each with lung cancer, lymphoma, and metastases of the lung and the liver. In 207 tumor lesions unidimensional and bidimensional measurements were performed: 36 lesions of lung cancer, 51 lesions of lymphoma, and 60 lesions of metastases of the lung and the liver, respectively. We assigned the results to the corresponding response categories. RESULTS: For tumor assessment, the kappa statistic produced a high agreement of 0.94 between the two methods for assessment of therapeutic response. CONCLUSION: The unidimensional RECIST measurement is easier to perform in order to assess tumor size during treatment follow-up in oncologic radiology.

[Radiofrequency ablation of malignant liver tumors: use of a volumetric necrosis-tumor ratio for local control]. / Radiofrequenzablation von malignen Lebertumoren: Erlaubt ein volumetrischer Nekrose-/Tumor-Quotient eine Vorhersage zur lokalen Tumorkontrolle?

PURPOSE: Sufficient safety margins are essential for preventing local tumor recurrence after radiofrequency ablation RFA of malignant liver tumors. The aim was to determine the initial tumor volume, ablation necrosis volume, and the necrosis-tumor quotient in order to compare these parameters with the rate of local control during follow-up. MATERIALS AND METHODS: 35 patients with 53 tumor nodules (29 colorectal metastases and 24 HCC nodules) were enrolled. RFA procedures were performed under CT guidance with intravenous conscious sedation. Tumor volumes were measured based on CT data sets and the necrosis volume was assessed using the sum-of-area method. A volumetric necrosis/tumor quotient (NTQ) was calculated for all lesions. Follow-up examinations were performed after 3, 6, and 12 months and then on a yearly basis to identify local recurrent tumors. RESULTS: The CRC metastases and HCC nodules had a median tumor volume of 8.3 ml and 7.4 ml, respectively. The mean ablation volumes were 37.6 ml and 29.5 ml, respectively. This resulted in a median NTQ of 3.9 for metastases and 3.4 for HCC. The follow-up (mean time 18 months) revealed local tumor recurrence in 16 of 29 (55 %) metastases and 10 of 24 (42 %) HCC nodules. In lesions with local recurrence, the initial tumor volume was significantly greater and the NTQ was significantly smaller. A threshold value of 3.4 for NTQ has the highest predictive value for local tumor recurrence. CONCLUSION: The volumetric necrosis/tumor quotient NTQ makes it possible to predict the local outcome and can be used for the planning of additional therapy.

[Value of imaging for lymph node metastases from renal cell, bladder, prostate, penile, and testicular cancers]. / Wertigkeit der Bildgebung für die Lymphknotenmetastasierung beim Nierenzell-, Blasen-, Prostata- und Peniskarzinom sowie dem Hodentumor.

Computed tomography (CT) imaging is the standard method for the assessment of lymph node metastases in renal cell and testicular cancer. In bladder cancer and prostate cancer the results of CT are not convincing due to a large number of false-negative findings and the prognostic relevance of undetected metastases. For both entities recent studies revealed that MR lymphography using iron oxide particles allows the detection of small metastatic lymph nodes. For penile cancer reliable results for imaging of lymph node metastases do not exist. PET imaging using [(18)F]-fluorodeoxyglucose (FDG) is the modality of choice in therapy control of seminomas but has no defined value in other urological malignancies. PET with [(11)C] choline and [(11)C] acetate offers great potential in staging and restaging of prostate cancer. Further investigations are necessary to determine the role of these new methods.

[Magnetic resonance imaging (MRI) of the pelvis in diagnosing endometriosis]. / Magnetresonanztomographie (MRT) des Beckens bei Endometriose -- eine Ubersichtsarbeit.

Widely accepted as an established method in the diagnostic imaging of diseases of the female pelvis, magnetic resonance imaging (MRI) holds promising potential for the diagnosis of endometriosis. This review describes the general prerequisites for performing MRI scans of the pelvis and presents, based on recent studies, an imaging protocol suited to the diagnosis of endometriosis. Typical manifestations and sites of endometriosis are discussed and illustrated with sample images. For endometriotic cysts and implants, axial T (1)-weighted, fat-saturated turbo spin echo sequences (TSE) have the highest diagnostic value. In diagnosing adenomyosis, sagittal T (2)-weighted TSE sequences visualise changes in the uterine zonal anatomy. In essence, MRI is capable of detecting many manifestations of endometriosis in a non-invasive, yet reliable manner, and its value in relation to laparoscopy must be considered as complementary.

[New techniques in computed tomography. Significance for urology]. / Neue Techniken in der Computertomographie. Bedeutung für die Urologie.

Computed tomographic (CT) imaging has become the modality of choice for the assessment of patients with urological malignancies. Recently, multi-slice CT imaging was introduced, providing faster acquisition times and higher resolution leading to improved image quality. Several studies show that thin-slice, high-resolution acquisition strategies lead to an improved accuracy for T-staging, especially of renal cell carcinomas. Three-dimensional post-processing techniques for the visualization of the vascular supply as well as the ureter (CT-angiography and CT-urography) are helpful for surgical planning. Compared to conventional imaging strategies unenhanced CT images render higher sensitivities and specificities for detecting stone disease in patients with acute flank pain. In the USA unenhanced CT imaging has almost replaced conventional urography, as no contrast agent is administered and the examination time is shorter. PET/CT examinations provide information on the morphology and function of tumors in one examination. However, there are only few data available for the assessment of urologic tumors.

[Magnetic resonance imaging in the diagnosis of benign and malignant pelvic tumors]. / Magnetresonanztomographie benigner und maligner Tumoren des weiblichen Beckens.

Magnetic resonance imaging (MRI) is an accepted imaging method for diagnosing diseases of the female pelvis. This review article describes the role of MR imaging for the diagnosis of benign and malignant pelvic tumors. Sagittal T2-weighted fast spin echo sequences can be effectively applied to diagnose leiomyomas of the uterus and provide exact pretreatment measurements of size and localization. In the diagnostic work-up of endometrial carcinoma, fat-saturated, T1-weighted gradient echo sequences make it possible to determine precisely how deep myometrial infiltration extends and what tissue should be included in preoperative treatment planning. In cervical cancer staging, MRI permits both assessment of local tumor extent and determination of tumor volume for planning and monitoring radiotherapy. The usefulness of MRI in cervical cancer staging is, however, limited since not all early-stage cancer (FIGO stage IA and small stage IB tumors) can be detected. Hence, it appears that the use of MRI as a screening method for cervical cancer cannot be recommended. MRI can distinguish between benign and malignant ovarian tumors with high sensitivity and specificity. Standard and fat-saturated T1-weighted sequences usually can diagnose teratomas with a specificity of 100 %. Axial fat-saturated, contrast enhanced T1-weighted spin echo sequences are useful in the staging of malignant ovarian tumors since they facilitate evaluation of their internal structure and will disclose peritoneal metastases. Besides staging of ovarian cancer, MRI can be applied for localization and for monitoring treatment response.

Diagnosis in medullary thyroid cancer with [18F]FDG-PET and improvement using a combined PET/CT scanner.

Today, positron emission tomography (PET) investigation using fluorodeoxyglucose (FDG) is the most sensitive and specific single modality established for localizing metastases of medullary thyroid cancer (MTC). Even at calcitonin serum levels below 20 pg/ml, tumour localization may be successful in individual cases. However, especially in such early tumour stages, the morphological correlation using PET is unsatisfactory. With the newly available fixed combination of PET and computed tomography (PET/CT), this drawback can be overcome as PET/CT allows a point-by-point correlation of pathological function with morphological structure. Conventional PET alone yielded an approx 80 % sensitivity and specificity in MTC: a result that will be surpassed by the combined PET/CT scanner.

Combined PET/CT with iodine-124 in diagnosis of spread metastatic thyroid carcinoma: a case report.

Iodine-124 positron emission tomography (PET) is a useful 3D imaging technique for diagnosis and management of thyroid diseases. The difficulty in interpretation of the PET scans with highly selective tracers, such as iodine-124, is the lack of identifiable anatomical structures, so an accurate anatomical localization of foci presenting abnormal uptake is problematic. Consequently, a combined PET/CT scanner can resolve these difficulties by co-registering PET and CT data in a single session allowing a correlation of functional and morphologic imaging. A case is presented where iodine-124 produced by a clinical cyclotron and FDG were used to acquire images with a combined PET/CT scanner for clinical staging. On the basis of the PET/CT exams the treatment of the patient was modified.