The application of Gadopentate-Dimeneglumin has no impact on progression free and overall survival as well as renal function in patients with monoclonal plasma cell disorders if general precautions are taken.

OBJECTIVES: The current analysis investigated the prognostic significance of gadopentetate dimeglumine on survival and renal function in patients with monoclonal plasma cell disorders. METHODS: In this study 263 patients who had received gadopentetate dimeglumine within a prospective trial investigating dynamic contrast-enhanced magnetic resonance imaging (MRI) were compared with 335 patients who had undergone routine, unenhanced MRI. RESULTS: We found no significant prognostic impact of the application of contrast agent on progression-free survival in patients with either monoclonal gammopathy of undetermined significance, smouldering or symptomatic myeloma and no significant prognostic impact on overall survival in patients with symptomatic myeloma. Since renal impairment is a frequent complication of myeloma, and decreased renal function is associated with a higher risk of complications in patients receiving contrast agents, we evaluated the impact of contrast agent on renal function after 1 year. In the present analysis the only significant adverse impact on kidney function occurred in symptomatic myeloma patients who already had impaired renal parameters at baseline. Here, the renal function did not recover during therapy, whereas it did so in patients with normal or only slightly impaired renal function. CONCLUSION: If general recommendations are adhered to, gadopentetate dimeglumine can be safely applied in patients with monoclonal plasma cell disease.

Contrast-enhanced ultrasound monitoring of perfusion changes in hepatic neuroendocrine metastases after systemic versus selective arterial 177Lu/90Y-DOTATOC and 213Bi-DOTATOC radiopeptide therapy.

AIM: Radiopeptide therapy with beta emitter labeled (177)Lu/(90)Y- DOTA(0)-Phe(1)-Tyr(3)-octreotide (DOTATOC) and more recently also alpha emitting (213)Bi-DOTATOC are promising new treatments for neuroendocrine tumors. No early predictors for treatment response have been recognized and tumor-shrinkage after radiation therapy appears slowly. In some solid tumors a decline in tumor perfusion was found predictive of final treatment response but the gold standard multiphase computed tomography (CT) has a high radiation burden. Therefore we evaluated the ability of contrast-enhanced ultrasound (CEUS) to evaluate tumor perfusion as a response criteria. MATERIALS AND METHODS: 14 patients with hepatic neuroendocrine tumor (NET) metastases were enrolled in the retrospective study. Eleven patients were treated with beta-emitting (177)Lu/(90)Y-DOTATOC, either intravenous (i.v.) (n = 5) or intra-arterial (i.a.) (n = 6) and three patients received alpha-emitting (213)Bi-DOTATOC (i.a.). CEUS and contrast-enhanced CT (CE-CT) were performed before and 3 months after treatment. RESULTS: CE-CT and CEUS presented comparable results in the baseline study and in the assessment of perfusion changes due to the different treatment regimes. A therapy related decrease in tumor perfusion is an early predictor of longterm morphologic response. CONCLUSION: CEUS is available and radiation free technique which showed comparable results for perfusion and diameter of liver metastases compared to CE-CT. Intensity reduction in an arterial phase CEUS can be seen as a positive sign indicating long term tumor response to treatment. Therefore CEUS may be considered as an imaging modality for monitoring early treatment after focal alpha and beta targeted therapy.

[Imaging diagnostics of hyperparathyroidism]. / Bildgebende Diagnostik des Hyperparathyreoidismus.

Primary hyperparathyroidism is diagnosed by the presence of hypercalcemia, hypercalciuria and elevated serum levels of parathyroid hormone and is treated surgically by removal of the enlarged gland. Both ultrasound and 99m-Tc-MIBI scintigraphy are used to localize enlarged parathyroid glands. With sonography, enlarged parathyroid glands are hypoechoic and are most frequently found dorsally or caudally to the thyroid and medially to the carotid arteries. Ectopic parathyroid glands in the mediastinum can be detected by scintigraphy only. Computed tomography and magnetic resonance imaging are not primarily indicated. The sensitivity of ultrasound is 90% at best. Causes for false negative ultrasound examinations are ectopic glands in the mediastinum, small glands weighing less than 200 mg and large goiters which make assessment of the retrothyroid space difficult. Ultrasound and scintigraphy in combination can achieve a sensitivity of more than 90%. A combination of both is indicated prior to minimally invasive resection and in cases of recurrence or persistence of hyperparathyroidism after resection.

PET imaging with a [68Ga]gallium-labelled PSMA ligand for the diagnosis of prostate cancer: biodistribution in humans and first evaluation of tumour lesions.

PURPOSE: Prostate-specific membrane antigen (PSMA) is a cell surface protein with high expression in prostate carcinoma (PC) cells. Recently, procedures have been developed to label PSMA ligands with (68)Ga, (99m)Tc and (123/124/131)I. Our initial experience with Glu-NH-CO-NH-Lys-(Ahx)-[(68)Ga(HBED-CC)]((68)Ga-PSMA) suggests that this novel tracer can detect PC relapses and metastases with high contrast. The aim of this study was to investigate its biodistribution in normal tissues and tumour lesions. METHODS: A total of 37 patients with PC and rising prostate-specific antigen (PSA) levels were subjected to (68)Ga-PSMA positron emission tomography (PET)/CT. Quantitative assessment of tracer uptake was performed 1 and 3 h post-injection (p.i.) by analysis of mean and maximum standardized uptake values (SUVmean/max) of several organs and 65 tumour lesions. Subsequently, tumour to background ratios were calculated. RESULTS: The PET/CT images showed intense tracer uptake in both kidneys and salivary glands. Moderate uptake was seen in lacrimal glands, liver, spleen and in small and large bowel. Quantitative assessment revealed excellent contrast between tumour lesions and most normal tissues. Of 37 patients, 31 (83.8 %) showed at least one lesion suspicious for cancer at a detection rate of 60 % at PSA <2.2 ng/ml and 100 % at PSA >2.2 ng/ml. Median tumour to background ratios were 18.8 (2.4-158.3) in early images and 28.3 (2.9-224.0) in late images. CONCLUSION: The biodistribution of the novel (68)Ga-PSMA tracer and its ability to detect PC lesions was analysed in 37 patients. Within healthy organs, kidneys and salivary glands demonstrated the highest radiotracer uptake. Lesions suspicious for PC presented with excellent contrast as early as 1 h p.i. with high detection rates even at low PSA levels.

[Radiologic and nuclear medicine diagnosis and therapy of thyroid disorders: Part II: Malignant thyroid diseases]. / Radiologische und nuklearmedizinische Diagnostik und Therapie der Schilddrüsenerkrankungen : Teil II: Maligne Erkrankungen der Schilddrüse.

Malignant thyroid diseases have increased in recent years. The distinction between differentiated and non-differentiated thyroid carcinoma is essential for therapy and follow-up. The frequently diagnosed papillary and follicular thyroid carcinomas are differentiated and have a good prognosis. Clinical symptoms are relatively unspecific, however imaging and laboratory testing can often provide evidence for diagnosis of thyroid carcinoma. Therapy typically involves surgery, ablative radioiodine therapy and subsequent suppressive hormone substitution. The pillars of follow-up are diagnostic scintigraphy, sonography and laboratory tests. Redifferentiation or a change of the tracer can make dedifferentiated tumors again susceptible to nuclide therapy. New treatment options have become available with the introduction of tyrosine kinase inhibitors.

[Radiologic and nuclear medicine diagnosis and therapy of thyroid disorders. Part 1: Benign thyroid diseases]. / Nuklearmedizinische und radiologische Diagnostik und Therapie der Schilddrüsenerkrankungen. Teil 1: Benigne Erkrankungen der Schilddrüse.

The thyroid gland is one of the most important endocrine organs. It has multiple influences on physical and mental health. The most important benign diseases are goiter, thyroid adenomas and inflammation. The clinical, imaging and laboratory findings are often pathognomic. The therapy spectrum ranges from follow-up, to medication or definitive therapy by operation or radioiodine therapy.

Cancer with unknown primary: finding a needle in a hay stack.

Detection and resection of small neuroendocrine tumours (NET) is like finding a needle in a hay stack. Use of specific tracers such as (68)Ga-DOTATOC in a PET/CT study has been proven to have a high sensitivity and specificity to cells expressing somatostatin-SSR receptors. The use of (99m)Tc-Octreotide to detect neuroendocrine tumours during surgery is an effective adjunct for therapy. We here present a clinical case of patient with NET where these modalities help in both diagnostic and therapeutic surgery.

Comparison of neuroendocrine tumor detection and characterization using DOTATOC-PET in correlation with contrast enhanced CT and delayed contrast enhanced MRI.

PURPOSE: We evaluated the rate of successful characterization of gastroenteropancreatic neuroendocrine tumors (NETs) present with an increased somatostatin receptor, comparing CE-CT with CE-MRI, each in correlation with DOTATOC-PET. METHODS AND MATERIALS: 8 patients with GEP-NET were imaged using CE-MRI (Gd-EOB-DTPA), CE-CT (Imeron 400) and DOTATOC-PET. Contrast-enhancement of normal liver-tissue and metastasis was quantified with ROI-technique. Tumor delineation was assessed with visual-score in blind-read-analysis by two experienced radiologists. RESULTS: Out of 40 liver metastases in patients with NETs, all were detected by CE-MRI and the lesion extent could be adequately assessed, whereas CT failed to detect 20% of all metastases. The blind-read-score of CT in arterial and portal phase was median -0.65 and -1.4, respectively, and 2.7 for delayed-MRI. The quantitative ROI-analysis presented an improved contrast-enhancement-ratio with a median of 1.2, 1.6 and 3.3 for CE-CT arterial, portal-phase and delayed-MRI respectively. CONCLUSION: Late CE-MRI was superior to CE-CT in providing additionally morphologic characterization and exact lesion extension of hepatic metastases from neuroendocrine tumor detected with DOTATOC-PET. Therefore, late enhanced Gd-EOB-DTPA-MRI seems to be the adequate imaging modality for combination with DOTATOC-PET to provide complementary (macroscopic and molecular) tumor characterization in hepatic metastasized NETs.

3D printing based on imaging data: review of medical applications.

PURPOSE: Generation of graspable three-dimensional objects applied for surgical planning, prosthetics and related applications using 3D printing or rapid prototyping is summarized and evaluated. MATERIALS AND METHODS: Graspable 3D objects overcome the limitations of 3D visualizations which can only be displayed on flat screens. 3D objects can be produced based on CT or MRI volumetric medical images. Using dedicated post-processing algorithms, a spatial model can be extracted from image data sets and exported to machine-readable data. That spatial model data is utilized by special printers for generating the final rapid prototype model. RESULTS: Patient-clinician interaction, surgical training, medical research and education may require graspable 3D objects. The limitations of rapid prototyping include cost and complexity, as well as the need for specialized equipment and consumables such as photoresist resins. CONCLUSIONS: Medical application of rapid prototyping is feasible for specialized surgical planning and prosthetics applications and has significant potential for development of new medical applications.

Comparison of diagnostic quality and accuracy in color-coded versus gray-scale DCE-MR imaging display.

PURPOSE: The purpose of this study was to evaluate the diagnostic value and tumor-vascular display properties (microcirculation) of two different functional MRI post-processing and display (color and gray-scale display) techniques used in oncology. MATERIALS AND METHODS: The study protocol was approved by the IRB and written informed consent was obtained from all patients. 38 dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) data sets of patients with malignant pleural-mesothelioma were acquired and post-processed. DCE-MRI was performed at 1.5 tesla with a T1-weighted 2D gradient-echo-sequence (TR 7.0 ms, TE 3.9 ms, 15 axial slices, 22 sequential repetitions), prior and during chemotherapy. Subtracting first image of contrast-enhanced-dynamic series from the last, produced gray-scale images. Color images were produced using a pharmacokinetic two-compartment model. Eight raters, blinded to diagnosis, by visual assessment of post-processed images evaluated both diagnostic quality of the images and vasculature of the tumor using a rating scale ranging from -5 to +5. The scores for vasculature were assessed by correlating with the maximum amplitude of the total-tumor-ROI for accuracy. RESULTS: Color coded images were rated as significantly higher in diagnostic quality and tumor vascular score than gray-scale images (p < 0.001, 0.005). ROI signal amplitude analysis and vascular ratings on color coded images were better correlated compared to gray-scale images rating (p < 0.05). CONCLUSION: Color coded images were shown to have higher diagnostic quality and accuracy with respect to tumor vasculature in DCE-MRI, therefore their implementation in clinical assessment and follow-up should be considered for wider application.

[Multiple space-occupying lesions of the liver: a rare differential diagnosis]. / Multiple Raumforderungen der Leber : Eine seltene Differenzialdiagnose.

The case of a 73-year-old female patient with a known increase in tumor markers is described. The course of this patient shows that a definitive diagnosis can sometimes not be achieved with comprehensive laboratory and imaging investigations alone.

An optimized workflow for the integration of biological information into radiotherapy planning: experiences with T1w DCE-MRI.

Planning of radiotherapy is often difficult due to restrictions on morphological images. New imaging techniques enable the integration of biological information into treatment planning and help to improve the detection of vital and aggressive tumour areas. This might improve clinical outcome. However, nowadays morphological data sets are still the gold standard in the planning of radiotherapy. In this paper, we introduce an in-house software platform enabling us to combine images from different imaging modalities yielding biological and morphological information in a workflow driven approach. This is demonstrated for the combination of morphological CT, MRI, functional DCE-MRI and PET data. Data of patients with a tumour of the prostate and with a meningioma were examined with DCE-MRI by applying pharmacokinetic two-compartment models for post-processing. The results were compared with the clinical plans for radiation therapy. Generated parameter maps give additional information about tumour spread, which can be incorporated in the definition of safety margins.

[MR-based methods of the functional imaging of the central nervous system]. / MR-basierte Methoden der funktionellen Bildgebung des zentralen Nervensystems.

This review presents the basic principles of functional imaging of the central nervous system utilizing magnetic resonance imaging. The focus is set on visualization of different functional aspects of the brain and related pathologies. Additionally, clinical cases are presented to illustrate the applications of functional imaging techniques in the clinical setting. The relevant physics and physiology of contrast-enhanced and non-contrast-enhanced methods are discussed. The two main functional MR techniques requiring contrast-enhancement are dynamic T1- and T2*-MRI to image perfusion. Based on different pharmacokinetic models of contrast enhancement diagnostic applications for neurology and radio-oncology are discussed. The functional non-contrast enhanced imaging techniques are based on "blood oxygenation level dependent (BOLD)-fMRI and arterial spin labeling (ASL) technique. They have gained clinical impact particularly in the fields of psychiatry and neurosurgery.