Oliver Dudeck

Detection and characterisation of focal liver lesions in colorectal carcinoma patients: comparison of diffusion-weighted and Gd-EOB-DTPA enhanced MR imaging

ObjectiveTo compare diffusion-weighted imaging (DWI) and Gd-EOB-DTPA-enhanced magnetic resonance (MR) imaging for the detection and characterisation of focal liver lesions (FLLs) in patients with colorectal carcinoma.MethodsSeventy-three patients underwent MR imaging including echoplanar DWI (MR-DWI) and dynamic (MR-Dyn) and hepatobiliary phase (MR-Late) Gd-EOB-DTPA-enhanced images. Two blinded readers independently reviewed 5 different image sets using a 5-point confidence scale. Accuracy was assessed by the area (Az) under the receiver operating characteristic curve, and sensitivity and specificity were calculated.ResultsA total of 332 FLLs were evaluated. Detection rates were significantly higher for MR-Late images (94.4% for benign and 100% for malignant lesions) compared with MR-DWI (78.3% and 97.5%) and MR-Dyn images (81.5% and 89.9%). Accuracy was 0.82, 0.76 and 0.89 for MR-DWI, MR-Dyn and MR-Late images while sensitivity was 0.98, 0.87 and 0.95, respectively. For characterisation of subcentimetre lesions sensitivity was highest for MR-DWI (0.92). Combined reading of unenhanced and contrast-enhanced images had an identical high accuracy of 0.98.ConclusionLate-phase Gd-EOB-DTPA-enhanced images were superior for the detection of FLLs, while DWIs were most valuable for the identification of particularly small metastases. Combined interpretation of unenhanced images resulted in precise characterisation of FLLs.

123I-IMT SPECT and 1HMR-Spectroscopy at 3.0T in the Differential Diagnosis of Recurrent or Residual Gliomas: A Comparative Study

The aim of this investigation was to compare two current non-invasive modalities, single photon emission tomography (SPECT) using 123-iodine-α-methyl tyrosine (123I-IMT) and single-voxel proton magnetic resonance spectroscopy (1H-MRS) at 3.0 T, with regard to their ability to differentiate between residual/recurrent tumors and treatment-related changes in patients pretreated for glioma. The patient population comprised 25 patients in whom recurrent glioma was suspected based on MR imaging. SPECT imaging started 10 min after iv. injection of 300–370 MBq 123I-IMT and was performed using a triple-head system. The IMT uptake was calculated semiquantitatively using regions-of-interest. 1H-MRS was performed at 3.0 T using the single-volume point-resolved spectroscopy (PRESS) technique. Guided by MR imaging volumes-of-interest for spectroscopy were placed into the suspected lesions. Signal intensities of choline-containing compounds (Cho), creatine and phosphocreatine (Cr), and N-acetylaspartate (NAA) were obtained. When using the cut-off of 1.62 for 123I-IMT uptake, the sensitivity, specificity, and accuracy of the 123I-IMT SPECT were 95, 100 and 96%, respectively. For 1H-MRS, the sensitivity, specificity and accuracy were 89, 83 and 88%, respectively, based both on the metabolic ratios of Cho/Cr and Cho/NAA as tumor criterion with cut-off values of 1.11 and 1.17, respectively. In conclusion, 123I-IMT SPECT yielded more favorable results compared to 1H-MRS at distinguishing recurrent and/or residual glioma from post-therapeutic changes and may be particularly valuable when the evaluation of tumor extent is necessary.

Predictive Value of Intratumoral 99mTc-Macroaggregated Albumin Uptake in Patients with Colorectal Liver Metastases Scheduled for Radioembolization with 90Y-Microspheres

90Y radioembolization is a promising therapy for patients with primary and secondary liver malignancies. Pretherapeutic assessment consists of hepatic angiography and 99mTc-macroaggregated albumin (99mTc-MAA) perfusion scintigraphy to estimate the liver-to-lung shunt and exclude extrahepatic 99mTc-MAA deposition. However, the predictive value of intratumoral 99mTc-MAA uptake remains unclear. Methods: One hundred four patients with chemotherapy-refractory liver-dominant metastatic colorectal cancer were treated with 90Y radioembolization between December 2006 and December 2010. All of the patients underwent angiographic assessment and perfusion scintigraphy with 99mTc-MAA before lobar 90Y radioembolization. For inclusion, patients must have undergone pretherapeutic and follow-up MR imaging (6 wk and 3 mo after radioembolization, respectively). The degree of intratumoral 99mTc-MAA uptake was rated, and liver metastases were classified according to changes in tumor diameter on both an individual and a patient basis using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. Response at both time points, MAA uptake, and catheter position were then statistically analyzed in a linear and generalized linear mixed model at a significance level of 0.05 (P value). Results: Sixty-six patients with a total of 435 colorectal liver metastases (mean number of lesions ± SD, 6.6 ± 2.8; mean lesion size ± SD, 33.8 ± 21.2 mm; lesion size range, 10–154 mm) were included in this analysis. According to the patient-based analysis, 3 patients had partial response, 49 stable disease, and 6 progressive disease after 6 wk. After 3 mo, 5 patients showed partial response, 26 stable disease, and 17 progressive disease. There was no association of patient-based tumor response with overall 99mTc-MAA uptake (P = 0.172) or with catheter position (P = 0.6456). Furthermore, an interaction effect of 99mTc-MAA uptake and catheter position in relation to tumor response was not found (P = 0.512). Moreover, in lesion-based analysis according to RECIST 1.1 there was no association of tumor response with degree of 99mTc-MAA uptake, catheter position, or interaction of 99mTc-MAA uptake and catheter position (P = 0.339, 0.593, and 0.658, respectively). Conclusion: Response to 90Y radioembolization was found to be independent of the degree of 99mTc-MAA uptake. Therefore, therapy should not be withheld from patients with colorectal liver metastases lacking intratumoral 99mTc-MAA accumulation.

Angiography in the Isolated Perfused Kidney: Radiological Evaluation of Vascular Protection in Tissue Ablation by Nonthermal Irreversible Electroporation

PurposeThe nonthermal irreversible electroporation (NTIRE) is a novel nonthermal tissue ablation technique by local application of high-voltage current within microseconds leading to a delayed apoptosis. The purpose of this experimental study was the first angiographic evaluation of the acute damage of renal vascular structure in NTIRE.MethodsResults of conventional dynamic digital substraction angiography (DSA) and visualization of the terminal vascular bed of renal parenchyma by high-resolution X-ray in mammography technique were evaluated before, during, and after NTIRE of three isolated perfused porcine ex vivo kidneys.ResultsIn the dedicated investigation, no acute vascular destruction of the renal parenchyma and no dysfunction of the kidney perfusion model were observed during or after NTIRE. Conspicuous were concentric wave-like fluctuations of the DSA contrast agent simultaneous to the NTIRE pulses resulting from NTIRE pulse shock wave.ConclusionThe NTIRE offers an ablation method with no acute collateral vascular damage in angiographic evaluation.

Radiotherapy of Liver Metastases Comparison of Target Volumes and Dose-Volume Histograms Employing CT- or MRI-Based Treatment Planning

Purpose:To assess differences in delineated target volumes of liver metastases using contrast-enhanced CT and different MRI sequences for radiation treatment planning.Patients and Methods:25 patients with 43 colorectal liver metastases were recruited. Tumor margins were defined by two experienced radiologists. The resulting D90 was assessed and the CT-based 3-D dose distribution merged with the according MRI dataset by employing image fusion. A theoretical D90 as a result of MRI-based treatment planning was assessed for various MRI sequences individually.Results:In venous phase contrast-enhanced CT, the mean tumor volume was 20 ml; T1-weighted (T1w) MRI, 27 ml; contrast-enhanced T1w 42 ml; T2w 65 ml. The difference between the target volumes as assessed by either CT or MRI was 181% for T1w images, 178% for contrast-enhanced T1w, and 246% for T2w sequences. All differences were statistically significant (p < 0.05).The analysis of the dose-volume histograms revealed statistically significant differences (i.e., for the D90) for the different target volumes specified by CT and MRI: mean D90 on CT, 18 Gy; plain T1w, 16 Gy; contrast-enhanced T1w, 15.5 Gy; T2w, 12 Gy. Hence, delineation of a larger target volume in T2w MRI compared to contrast-enhanced CT resulted in a smaller D90.The mean differences of tumor volumes assessed by CT and plain T1w were significantly higher in the group of patients showing local tumor recurrences as compared to patients with long-term local tumor control (p = 0.002).Conclusion:For treatment planning of liver metastases, the use of either plain T1w or T2w sequences is recommended to delineate the clinical target volume as completely as possible and not to miss potential tumor cell congregations in the surroundings as in CT.Ziel:Beurteilung von Unterschieden in der Abgrenzung von Zielvolumina bei kontrastmittelverstärkter CT- und MRT-gestützter Bestrahlungsplanung.Patienten und Methodik:25 Patienten mit 43 Lebermetastasen kolorektalen Ursprungs wurden in dieser Studie untersucht. Zur Definition der Zielvolumina wurden CT- und MRT-Untersuchungen verwendet, die Konturierung der Tumorränder wurde von zwei erfahrenen Radiologen vorgenommen. Die D90 wurde nach Bildfusionierung der CT-basierten dreidimensionalen Dosisverteilungen mit den MRT-Datensätzen beurteilt. Eine theoretische D90 als Resultat der MRT-basierten Bestrahlungsplanung wurde bestimmt.Ergebnisse:In der venösen Phase der kontrastmittelverstärkten CT-Untersuchung betrug das mittlere Tumorvolumen 20 ml; MRT T1-gewichtet (T1w) 27 ml; kontrastmittelverstärkte T1w 42 ml; T2w 65 ml. Die Unterschiede der Zielvolumina im Verhältnis zur CT-gestützten Planung betrugen 181% für T1w-, 178% für kontrastmittelverstärkte T1w- und 246% für T2w-Sequenzen. Alle Unterschiede stellten sich als signifikant heraus (p < 0,05). Im Vergleich zur kontrastmittelverstärkten CT resultierte somit das Bemessen des Tumorvolumens im T2w MRT in einer niedrigeren D90.Die Analyse der Dosis-Volumen-Histogramme zeigte signifikante Unterschiede der verschiedenen Volumina. Die mittlere D90 betrug bei CT 18 Gy, bei nativer T1w 16 Gy, bei kontrastmittelverstärkter T1w 15,5 Gy und bei T2w 12 Gy.Die mittleren Unterschiede des Zielvolumens durch CT- und native T1w-gestützte MRT-Bestrahlungsplanung waren in der Gruppe der Patienten mit lokalen Tumorrezidiven signifikant höher als in der Gruppe mit langfristiger lokaler Kontrolle (p = 0,002).Schlussfolgerung:Für die Bestrahlungsplanung der Therapie von Lebermetastasen wird die Verwendung von nativen T1w- oder T2w-Sequenzen zur Abgrenzung des Zielvolumens empfohlen, um eine möglichst vollständige Erfassung der Metastase einschließlich evtl. vorhandener peripherer Tumorausläufer zu erreichen.

Epidural venous enlargements presenting with intractable lower back pain and sciatica in a patient with absence of the infrarenal inferior vena cava and bilateral deep venous thrombosis.

Study Design. Case report. Objective. To present a rare anomaly of the inferior vena cava associated with radicular pain and to illustrate its imaging characteristics. Summary of Background Data. Irritation of the trigeminal nerve by vascular anomalies, resulting in neuralgia is a well-recognized entity. Recently, compression of peripheral nerve roots due to enlarged epidural venous plexus has been described as a possible cause of back and radicular pain, too. Methods. A 26-year-old man presented with acute exacerbation of lower back pain associated with radiculopathy down his left thigh. On radiologic workup, a prolapse of a lumbar intervertebral disc was ruled out, but agenesis of the infrarenal segment of the inferior vena cava was found, which has caused bilateral deep venous thrombosis. Venous flow was redirected mainly via enlarged lumbar epidural, ascending lumbar, and paravertebral veins. Results. No associated congenital heart or abdominal organ defects were found and screening for thrombophilia was negative. The patient was successfully treated with anticoagulation under which symptoms gradually resolved. Conclusion. The authors believe that epidural venous enlargements should be considered as a cause of radicular and/or back pain in patients with anomalies of the inferior vena cava, because pathologic processes compressing nervous structures can cause pain.

CT-guided brachytherapy (CTGB) versus interstitial laser ablation (ILT) of colorectal liver metastases: an intraindividual matched-pair analysis.

Purpose:To compare local tumor control after percutaneous tumor ablation by interstitial laser therapy (ILT) or CT-guided brachytherapy (CTGB).Patients and Methods:In a matched pair analysis including 18 patients with 36 liver metastases of colorectal primary, both ILT and CTGB were performed in different lesions. The following matching factors were considered: (i) tumor size ≤ 5 cm, and (ii) execution of chemotherapy after tumor ablation. Primary endpoint was local tumor control.Results:Treated lesions were identical in terms of tumor size and all matching criteria were fulfilled in all patients except for the performance of adjuvant chemotherapy. Median follow-up was 14 months (3–24 months) for both groups. Only five of 18 patients (28%) demonstrated local tumor progression after CTGB, whereas in ten of 18 patients (56%) tumor progression was found after ILT. Differences encountered were significant for all patients (p = 0.04), whereas in those who fulfilled all matching criteria (n = 14) the level of statistical significance was not reached (p = 0.23).Conclusion:CTGB demonstrated superior local tumor control compared to ILT in long-term follow-up.Ziel:Intraindividueller Vergleich lokaler Kontrollraten nach perkutaner Tumorablation mit interstitieller Lasertherapie (ILT) oder CT-gestützter Brachytherapie (CTGB) von intrahepatischen Metastasen bei kolorektalem Karzinom.Patienten und Methodik:Eine Matched-Pair-Analyse wurde bei 18 Patienten mit insgesamt 36 Lebermetastasen eines kolorektalen Karzinoms durchgeführt. Je eine Metastase wurde mit perkutaner Tumorablation mit ILT und je eine mit CTGB behandelt. Bei den Patienten mit identischer Tumorhistologie wurden folgende Faktoren betrachtet: 1. Tumorgröße ≤ 5 cm und 2. Durchführung oder Verzicht auf eine adjuvante Chemotherapie. Als primärer Endpunkt wurde die lokale Tumorkontrolle definiert.Ergebnisse:Die Verteilung der Tumorgrößen war gleich, und alle Patienten erreichten volle Übereinstimmung bis auf den Vergleichsfaktor der adjuvanten Chemotherapie. Die mediane Beobachtungszeit betrug 14 Monate (3–24 Monate) für beide Gruppen. Fünf von 18 Patienten (28%) hatten eine lokale Tumorprogression nach CTGB und zehn von 18 Patienten (56%) nach ILT. Die Differenz zwischen den Gruppen war für alle Patienten signifikant (p = 0,04). Bei der Betrachtung der Patienten mit völliger Übereinstimmung wurde die Signifikanzgrenze nicht erreicht (p = 0,23).Schlussfolgerung:Die CTGB zeigt in der Langzeitbeobachtung überlegene lokale Tumorkontrollraten im Vergleich zur ILT.

Value of diffusion weighted MR imaging as an early surrogate parameter for evaluation of tumor response to high-dose-rate brachytherapy of colorectal liver metastases

BackgroundTo assess the value of diffusion weighted imaging (DWI) as an early surrogate parameter for treatment response of colorectal liver metastases to image-guided single-fraction 192Ir-high-dose-rate brachytherapy (HDR-BT).MethodsThirty patients with a total of 43 metastases underwent CT- or MRI-guided HDR-BT. In 13 of these patients a total of 15 additional lesions were identified, which were not treated at the initial session and served for comparison. Magnetic resonance imaging (MRI) including breathhold echoplanar DWI sequences was performed prior to therapy (baseline MRI), 2 days after HDR-BT (early MRI) as well as after 3 months (follow-up MRI). Tumor volume (TV) and intratumoral apparent diffusion coefficient (ADC) were measured independently by two radiologists. Statistical analysis was performed using univariate comparison, ANOVA and paired t test as well as Pearsons correlation.ResultsAt early MRI no changes of TV and ADC were found for non-treated colorectal liver metastases. In contrast, mean TV of liver lesions treated with HDR-BT increased by 8.8% (p = 0.054) while mean tumor ADC decreased significantly by 11.4% (p < 0.001). At follow-up MRI mean TV of non-treated metastases increased by 50.8% (p = 0.027) without significant change of mean ADC values. In contrast, mean TV of treated lesions decreased by 47.0% (p = 0.026) while the mean ADC increased inversely by 28.6% compared to baseline values (p < 0.001; Pearsons correlation coefficient of r = -0.257; p < 0.001).ConclusionsDWI is a promising imaging biomarker for early prediction of tumor response in patients with colorectal liver metastases treated with HDR-BT, yet the optimal interval between therapy and early follow-up needs to be elucidated.

Radiotherapy of Liver Metastases

Purpose:To assess differences in delineated target volumes of liver metastases using contrast-enhanced CT and different MRI sequences for radiation treatment planning.Patients and Methods:25 patients with 43 colorectal liver metastases were recruited. Tumor margins were defined by two experienced radiologists. The resulting D90 was assessed and the CT-based 3-D dose distribution merged with the according MRI dataset by employing image fusion. A theoretical D90 as a result of MRI-based treatment planning was assessed for various MRI sequences individually.Results:In venous phase contrast-enhanced CT, the mean tumor volume was 20 ml; T1-weighted (T1w) MRI, 27 ml; contrast-enhanced T1w 42 ml; T2w 65 ml. The difference between the target volumes as assessed by either CT or MRI was 181% for T1w images, 178% for contrast-enhanced T1w, and 246% for T2w sequences. All differences were statistically significant (p < 0.05).The analysis of the dose-volume histograms revealed statistically significant differences (i.e., for the D90) for the different target volumes specified by CT and MRI: mean D90 on CT, 18 Gy; plain T1w, 16 Gy; contrast-enhanced T1w, 15.5 Gy; T2w, 12 Gy. Hence, delineation of a larger target volume in T2w MRI compared to contrast-enhanced CT resulted in a smaller D90.The mean differences of tumor volumes assessed by CT and plain T1w were significantly higher in the group of patients showing local tumor recurrences as compared to patients with long-term local tumor control (p = 0.002).Conclusion:For treatment planning of liver metastases, the use of either plain T1w or T2w sequences is recommended to delineate the clinical target volume as completely as possible and not to miss potential tumor cell congregations in the surroundings as in CT.Ziel:Beurteilung von Unterschieden in der Abgrenzung von Zielvolumina bei kontrastmittelverstärkter CT- und MRT-gestützter Bestrahlungsplanung.Patienten und Methodik:25 Patienten mit 43 Lebermetastasen kolorektalen Ursprungs wurden in dieser Studie untersucht. Zur Definition der Zielvolumina wurden CT- und MRT-Untersuchungen verwendet, die Konturierung der Tumorränder wurde von zwei erfahrenen Radiologen vorgenommen. Die D90 wurde nach Bildfusionierung der CT-basierten dreidimensionalen Dosisverteilungen mit den MRT-Datensätzen beurteilt. Eine theoretische D90 als Resultat der MRT-basierten Bestrahlungsplanung wurde bestimmt.Ergebnisse:In der venösen Phase der kontrastmittelverstärkten CT-Untersuchung betrug das mittlere Tumorvolumen 20 ml; MRT T1-gewichtet (T1w) 27 ml; kontrastmittelverstärkte T1w 42 ml; T2w 65 ml. Die Unterschiede der Zielvolumina im Verhältnis zur CT-gestützten Planung betrugen 181% für T1w-, 178% für kontrastmittelverstärkte T1w- und 246% für T2w-Sequenzen. Alle Unterschiede stellten sich als signifikant heraus (p < 0,05). Im Vergleich zur kontrastmittelverstärkten CT resultierte somit das Bemessen des Tumorvolumens im T2w MRT in einer niedrigeren D90.Die Analyse der Dosis-Volumen-Histogramme zeigte signifikante Unterschiede der verschiedenen Volumina. Die mittlere D90 betrug bei CT 18 Gy, bei nativer T1w 16 Gy, bei kontrastmittelverstärkter T1w 15,5 Gy und bei T2w 12 Gy.Die mittleren Unterschiede des Zielvolumens durch CT- und native T1w-gestützte MRT-Bestrahlungsplanung waren in der Gruppe der Patienten mit lokalen Tumorrezidiven signifikant höher als in der Gruppe mit langfristiger lokaler Kontrolle (p = 0,002).Schlussfolgerung:Für die Bestrahlungsplanung der Therapie von Lebermetastasen wird die Verwendung von nativen T1w- oder T2w-Sequenzen zur Abgrenzung des Zielvolumens empfohlen, um eine möglichst vollständige Erfassung der Metastase einschließlich evtl. vorhandener peripherer Tumorausläufer zu erreichen.

CT-Guided Brachytherapy (CTGB) versus Interstitial Laser Ablation (ILT) of Colorectal Liver Metastases

Purpose:To compare local tumor control after percutaneous tumor ablation by interstitial laser therapy (ILT) or CT-guided brachytherapy (CTGB).Patients and Methods:In a matched pair analysis including 18 patients with 36 liver metastases of colorectal primary, both ILT and CTGB were performed in different lesions. The following matching factors were considered: (i) tumor size ≤ 5 cm, and (ii) execution of chemotherapy after tumor ablation. Primary endpoint was local tumor control.Results:Treated lesions were identical in terms of tumor size and all matching criteria were fulfilled in all patients except for the performance of adjuvant chemotherapy. Median follow-up was 14 months (3–24 months) for both groups. Only five of 18 patients (28%) demonstrated local tumor progression after CTGB, whereas in ten of 18 patients (56%) tumor progression was found after ILT. Differences encountered were significant for all patients (p = 0.04), whereas in those who fulfilled all matching criteria (n = 14) the level of statistical significance was not reached (p = 0.23).Conclusion:CTGB demonstrated superior local tumor control compared to ILT in long-term follow-up.Ziel:Intraindividueller Vergleich lokaler Kontrollraten nach perkutaner Tumorablation mit interstitieller Lasertherapie (ILT) oder CT-gestützter Brachytherapie (CTGB) von intrahepatischen Metastasen bei kolorektalem Karzinom.Patienten und Methodik:Eine Matched-Pair-Analyse wurde bei 18 Patienten mit insgesamt 36 Lebermetastasen eines kolorektalen Karzinoms durchgeführt. Je eine Metastase wurde mit perkutaner Tumorablation mit ILT und je eine mit CTGB behandelt. Bei den Patienten mit identischer Tumorhistologie wurden folgende Faktoren betrachtet: 1. Tumorgröße ≤ 5 cm und 2. Durchführung oder Verzicht auf eine adjuvante Chemotherapie. Als primärer Endpunkt wurde die lokale Tumorkontrolle definiert.Ergebnisse:Die Verteilung der Tumorgrößen war gleich, und alle Patienten erreichten volle Übereinstimmung bis auf den Vergleichsfaktor der adjuvanten Chemotherapie. Die mediane Beobachtungszeit betrug 14 Monate (3–24 Monate) für beide Gruppen. Fünf von 18 Patienten (28%) hatten eine lokale Tumorprogression nach CTGB und zehn von 18 Patienten (56%) nach ILT. Die Differenz zwischen den Gruppen war für alle Patienten signifikant (p = 0,04). Bei der Betrachtung der Patienten mit völliger Übereinstimmung wurde die Signifikanzgrenze nicht erreicht (p = 0,23).Schlussfolgerung:Die CTGB zeigt in der Langzeitbeobachtung überlegene lokale Tumorkontrollraten im Vergleich zur ILT.