Noninvasive CSF shunt patency evaluation by superb microvascular imaging.

Occlusion of a ventriculoperitoneal shunt system is a potentially life-threatening complication in patients suffering from hydrocephalus. However, there is no imaging established as standard approach in this acute setting. In the present study, we evaluate the use of superb microvascular imaging for investigation of the patency of ventriculoperitoneal shunt systems. Simulation of low flow rates of cerebrospinal fluid through a small diameter CSF shunt system was performed in a dedicated phantom in order to proof the principle of superb microvascular imaging (SMI) being feasible for the measurement of slow CSF flow through the dedicated CSF shunt system. SMI is able to detect low flow rates in CSF shunt systems effectively and fast. Visualization of a Duplex ultrasound flow and Doppler wave pattern in the VP shunt system after the reservoir has been pressed confirms patency. SMI is an effective method for evaluating CSF shunt patency and diagnosing shunt obstruction. This bears the potential to facilitate evaluation of clinically symptomatic VP shunt patients in an acute setting. Further evaluation of ultrasound flow patterns is granted.

Raman microscopic spectroscopy as a diagnostic tool to detect Staphylococcus epidermidis in bone grafts.

INTRODUCTION: Raman microscopic spectroscopyis a new approach for further characterization and detection of molecular features in many pathological processes. This technique has been successfully applied to scrutinize the spatial distribution of small molecules and proteins within biological systems by in situ analysis. This study uses Raman microscopic spectroscopyto identify any in-depth benefits and drawbacks in diagnosing Staphylococcus epidermidis in human bone grafts. MATERIAL AND METHODS: 40 non-infected human bone samples and 10 human bone samples infected with Staphylococcus epidermidis were analyzed using Raman microscopic spectroscopy. Reflectance data were collected between 200 cm-1 and 3600 cm-1 with a spectral resolution of 4 cm-1 using a Senterra II microscope (Bruker, Ettlingen, Germany). The acquired spectral information was used for spectral and unsupervised classification, such as principal component analysis. RESULTS: Raman measurements produced distinct diagnostic spectra that were used to distinguish between non-infected human bone samples and Staphylococcus epidermidis infected human bone samples by spectral and principal component analyses. A substantial loss in bone quality and protein conformation was detected by human bone samples co-cultured with Staphylococcus epidermidis. The mineral-to-matrix ratio using the phosphate/Amide I ratio (p = 0.030) and carbonate/phosphate ratio (p = 0.001) indicates that the loss of relative mineral content in bones upon bacterial infection is higher than in non-infected human bones. Also, an increase of alterations in the collagen network (p = 0.048) and a decrease in the structural organization and relative collagen in infected human bone could be detected. Subsequent principal component analyses identified Staphylococcus epidermidis in different spectral regions, respectively, originating mainly from CH2 deformation (wagging) of protein (at 1450 cm-1) and bending and stretching modes of C-H groups (∼2800-3000 cm-1). CONCLUSION: Raman microscopic spectroscopyis presented as a promising diagnostic tool to detect Staphylococcus epidermidis in human bone grafts. Further studies in human tissues are warranted.

Accuracy of digital templating of uncemented total hip arthroplasty at a certified arthroplasty center: a retrospective comparative study.

INTRODUCTION: To investigate the accuracy of preoperative digital templating for total hip arthroplasty (THA) at a certified arthroplasty center (EndoCert EPZmax). MATERIALS AND METHODS: In a retrospective study design, we analysed 620 uncemented primary THAs for templating accuracy by comparing the preoperatively planned THA component size and the implanted size as documented by the surgeon. Templating was determined to be a) exact if the planned and the implanted component were the same size and b) accurate if they were exact ± one size. Moreover, we investigated factors that potentially influence templating accuracy: overweight and obesity (WHO criteria), sex, implant design, surgeon experience, preoperative diagnosis. Digital templating was done with MediCAD software. The Mann-Whitney U test and the Kruskal-Wallis test were used for statistical analysis. RESULTS: Templating was exact in 52% of stems and 51% of cups and was accurate in 90% of the stems and 85% of the cups. Regarding the factors potentially influencing templating accuracy, the type of cup implant had a significant influence (p = 0.016). Moreover, greater accuracy of stem templating was achieved in female patients (p = 0.004). No such effect was determined for the other factors investigated. CONCLUSIONS: We conclude that preoperative 2D templating is accurate in 90% of the stems and 85% of the cups. Greater accuracy may be achieved in female patients. In addition to gender, the type of implant used may influence planning accuracy as well. Surgeon experience, BMI and preoperative diagnosis did not influence templating accuracy. LEVEL OF EVIDENCE: Level III (retrospective comparative study with prospective cohort).

Tissue characterization of the medical fungus Hericium coralloides by focus-variation microscopy.

In this study, the potential of focus-variation microscopic imaging was evaluated in a study of morphological patterns of the potential medicinal fungus Hericium coralloides (Basidiomycota). We created three-dimensional reconstructions and visualizations using the imaging technique on a fresh H. coralloides basidioma. The aim was to approximate the spore dispersal efficiency of this basidiomata type regarding the investment of tissue biomass and its reproductive output (production of basidiospores). Results were correlated with published data gained from magnetic resonance imaging and micro-computed tomography. It is demonstrated that focus-variation microscopic imaging results in a more distinct picture of the morphology of the edible and potentially medicinal H. coralloides basidiomata. However, a direct measurement of spore production was not possible. Spore production could only be estimated in combination with a mathematical model because the surface was not directly measurable due to the cellular heterogeneity. However, focus-variation microscopic imaging allows a better and faster estimation of spore production compared with the published methods. Furthermore, it was found that a scanning resolution of 5× is sufficient for determining the fungal surface precisely because at a higher resolution artifacts occur, resulting in adulteration of the image.

[A multidimensional v-shaped distalizing osteotomy of the tibial tuberosity with a proximal buttress ("coffin-shaped" osteotomy)]. / Die multiplanare v-förmige distalisierende Tuberositasosteotomie mit proximalem Widerlager ("sargförmige" Osteotomie).

The aim of the intervention presented is a distalization of the tibial tuberosity. It is indicated in patients with symptomatic patella alta, i.e. patients with instability of the patella. It facilitates a V-shaped osteotomy. The bone gained during distalization is used as a proximal buttress. This leads to an improved mediolateral and proximal stability. The bony surface area is increased, which improves bony healing. There were no secondary dislocations in the patient group of 10 patients treated by the surgeon.

Different wear in two highly cross-linked polyethylene liners in THA: wear analysis with EBRA.

INTRODUCTION: The purpose of this study was (1) to compare early wear rates in bedding-in periods of two highly cross-linked polyethylene liners frequently used in THA and (2) to evaluate risk factors indicating a possible higher wear rate. MATERIALS AND METHODS: 1120 patients who received a Crossfire or a Marathon highly cross-linked (HXLPE) ultra-high-molecular-weight polyethylene liner in primary THA at our Department between 2004 and 2018 were retrospectively reviewed. Patients with (1) only alumina heads on HXLPE acetabular bearings, (2) a minimum of four radiographs per patient for EBRA analysis, (3) no osteolysis around the acetabular cup and (4) no dislocations that occurred during the study period were included. RESULTS: A total of 328 patients (female: 183; male: 145; Marathon: 179; Crossfire: 149) fulfilled the inclusion criteria. Mean follow-up was 24 (range 7-51) months. With 0.22 (SD 0.27) mm mean total wear for the Marathon was three times greater than for the Crossfire, namely 0.07 (SD 0.14) mm. Mean cup migration during the investigated follow-up period was 0.7 (SD 0.8) mm for the Pinnacle and 0.5 mm (SD 0.7) for the Trident PSL cups. CONCLUSION: Initial early wear of highly cross-linked polyethylene in combination with alumina heads differs strongly between products. Long-term survivorship of these liners should be observed to determine whether early wear has an impact on aseptic loosening. LEVEL OF EVIDENCE: Level III (retrospective comparative study with prospective cohort).

High risk of hip dislocation following polyethylene liner exchange in total hip arthroplasty-is cup revision necessary?

PURPOSE: Polyethylene (PE) wear remains a common reason for revision surgery following total hip arthroplasty (THA). An established treatment method is isolated liner exchange in a well-fixed acetabular cup and entails a known high risk of hip dislocation after revision surgery. The purpose of this retrospective study was to determine the rate of hip dislocation after liner exchange. METHODS: Patients were included if (1) the PE liner was removable, (2) the acetabular shell was stable with acceptable orientation, (3) no osteolysis around the acetabular cup was found and (4) no dislocation of the THA occurred before revision surgery. We reviewed medical histories and performed radiological measurements using Einzel-Bild-Röntgen-Analyse (EBRA) software. EBRA measurements and statistical investigations were performed by two independent investigators. RESULTS: A total of 82 patients were included in our study. Mean follow-up was six (range: 3.6-9.9) years. In 13 (15.8%) patients THA dislocations occurred at a mean postoperative period of 20.2 (range: 1-44) weeks after revising the PE liner. This is equivalent to an absolute risk increase of 16% after revision surgery, which results in a number needed to harm of 6. This means that every sixth patient with isolated liner exchange can expect to experience dislocation due to wear. CONCLUSION: In conclusion, isolated exchange of the polyethylene liner because of wear showed a high risk of dislocation and further cup revision. Our results suggest that the threshold for revising well-fixed components in the case of liner wear should be lowered. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION: Number: 20140710-1012 and Date: 2016-03-09.

Peri-operative brachial plexus injury following self-positioning for stereotactic radiofrequency ablation.

A 71-year-old woman with a known accessory cervical rib and distinct scoliosis was scheduled for elective, percutaneous stereotactic radiofrequency ablation of a non-resectable intrahepatic cholangiocellular carcinoma. Patient positioning and fixation using a Bluebag fixation system (Medical Intelligence, Schwabmünchen, Germany) and a dedicated adjustable armrest were customised in the patient while awake. In order to provide safe conditions for mask ventilation and tracheal intubation, the patient was returned to standard supine positioning without changing the position of the armrest. Following the induction of general anaesthesia, the patient's arm was returned to the previously defined position. Upon completion of the procedure and emergence from anaesthesia, the patient immediately reported symptoms of severe brachial plexus damage. Therefore, we suggest that awake positioning according to current recommendations does not completely preclude the possibility of neurologic injury.

Integrating interventional oncology in the treatment of liver tumors.

BACKGROUND: Percutaneous ablation techniques offer a vast armamentarium for local, minimally invasive treatment of liver tumors, nowadays representing an established therapeutic option, which is integrated in treatment algorithms, especially for non-resectable liver tumors. The results of ablative treatment compare very well to surgical treatment in liver lesions, and confirm that these techniques are a valuable option for bridging for transplantation. Different techniques have been established to perform tumor ablation, and the feasibility varies according to the procedure and technical skills of the operator, depending on the size and location of the liver lesion. In recent years, stereotactic multi-needle techniques using 3D trajectory planning, general anesthesia, and tube disconnection during needle placement have had a strong impact on the application range of ablation for liver tumors. CONCLUSION: It is well known that creating a sufficient ablation margin and overlapping ablation zones is one key issue to enable ablation of large liver lesions with tumor-free margins (A0 ablation in analogy to R0 resection). Image fusion during treatment and follow-up assure highly accurate staging procedures and interventional planning. NOVEL ASPECTS: Review on the standards in ablation techniques for the treatment of liver tumors. Update on different ablation techniques, indications, and contraindications for percutaneous liver tumor treatment. Summary of recently published reports on liver tumor ablation.

Comparison of Two Electromagnetic Navigation Systems For CT-Guided Punctures: A Phantom Study.

PURPOSE: We compared the targeting accuracy and reliability of two different electromagnetic navigation systems for manually guided punctures in a phantom. MATERIALS AND METHODS: CT data sets of a gelatin filled plexiglass phantom were acquired with 1, 3, and 5 mm slice thickness. After paired-point registration of the phantom, a total of 480 navigated stereotactic needle insertions were performed manually using electromagnetic guidance with two different navigation systems (Medtronic Stealth Station: AxiEM; Philips: PercuNav). A control CT was obtained to measure the target positioning error between the planned and actual needle trajectory. RESULTS: Using the Philips PercuNav, the accomplished Euclidean distances were 4.42 ±â€Š1.33 mm, 4.26 ±â€Š1.32 mm, and 4.46 ±â€Š1.56 mm at a slice thickness of 1, 3, and 5 mm, respectively. The mean lateral positional errors were 3.84 ±â€Š1.59 mm, 3.84 ±â€Š1.43 mm, and 3.81 ±â€Š1.71 mm, respectively. Using the Medtronic Stealth Station AxiEM, the Euclidean distances were 3.86 ±â€Š2.28 mm, 3.74 ±â€Š2.1 mm, and 4.81 ±â€Š2.07 mm at a slice thickness of 1, 3, and 5 mm, respectively. The mean lateral positional errors were 3.29 ±â€Š1.52 mm, 3.16 ±â€Š1.52 mm, and 3.93 ±â€Š1.68 mm, respectively. CONCLUSION: Both electromagnetic navigation devices showed excellent results regarding puncture accuracy in a phantom model. The Medtronic Stealth Station AxiEM provided more accurate results in comparison to the Philips PercuNav for CT with 3 mm slice thickness. One potential benefit of electromagnetic navigation devices is the absence of visual contact between the instrument and the sensor system. Due to possible interference with metal objects, incorrect position sensing may occur. In contrast to the phantom study, patient movement including respiration has to be compensated for in the clinical setting. KEY POINTS: • Commercially available electromagnetic navigation systems have the potential to improve the therapeutic range for CT guided percutaneous procedures by comparing the needle placement accuracy on the basis of planning CT data sets with different slice thickness. Citation Format: • Putzer D, Arco D, Schamberger B et al. Comparison of Two Electromagnetic Navigation Systems For CT-Guided Punctures: A Phantom Study. Fortschr Röntgenstr 2016; 188: 470 - 478.

[Calcaneo-fibular ligament surgery for chronic lateral instability of the upper ankle : Broström technique with modification by Wille. Video article]. / Fibulare Bandplastik bei chronischer lateraler Instabilität am oberen Sprunggelenk : Operationstechnik nach Broström in der Modifikation nach Wille. Videobeitrag.

BACKGROUND: An acute ligament rupture of the lateral ligament complex of the ankle joint is treated without surgery. Treatment failure may lead to a chronically unstable situation of the ankle joint, in which case surgery is an effective procedure for stabilizing the ruptured ligaments. Anatomical reconstruction is the best operative technique if the ligament tissue is of good quality. METHOD: In our video we demonstrate a new possibility for the positioning of an anchor to tighten the calcaneo-fibular ligament. Modified Broström repairs are described in the literature in which the calcaneo-fibular ligament is released and reattached to the fibula to tighten it. We present the option to release the ligament at the calcaneus and reattach it using a suture anchor. This offers the advantage of preventing the possible dislocation of the peroneal tendons.

[Arthroscopic procedure for Baker's cysts : surgical technique. Video article]. / Arthroskopische Operation der Baker-Zyste : Operationstechnik. Videobeitrag.

BACKGROUND: Baker's cysts are related to increased intra-articular pressure. The causes may be inflammatory, degenerative or traumatic disorders. Owing to the increased intra-articular pressure a cyst protrudes between the semimembranosus and the medial gastrocnemius tendons. The traditional treatment for a Baker's cyst is open resection. As an alternative, an arthroscopic procedure can be performed, which is demonstrated by the video on surgical technique that accompanies this short report. SURGICAL TECHNIQUE: From the anterolateral portal the arthroscope is advanced through the intercondylar notch (below the posterior cruciate ligament) to the posteromedial recess. Under visual control, a posteromedial portal is created followed by identification of the capsular fold separating the cyst from the joint cavity. This fold (valvular mechanism) is resected with a shaver from the posteromedial portal until a large enough connection exists between the joint and the cyst (cyst decompression). After the decompression, the arthroscope is inserted from the posteromedial portal directly into the cyst cavity. Subsequently, the inner wall of the cyst is removed with the shaver via an additional far posterior cystic portal. It is obligatory to treat the associated intra-articular pathological condition. In our video a medial meniscal lesion is treated with partial meniscectomy.

Reproducibility of contact heat evoked potentials (CHEPs) over a 6 months interval.

OBJECTIVE: Contact heat evoked potentials (CHEPs) mediated by primary afferent Aδ-fibers can be recorded at the vertex. CHEPs are reduced in small fibre neuropathy and considered as a noninvasive measure of small fibre function. As long-term stability of CHEPs has not been examined, it is presently not clear if CHEPs may also be useful for following the course of small fibre neuropathy. METHODS: Here, we analyzed CHEPs from 60 healthy subjects recorded at two occasions separated by 6 months. RESULTS: There was a systematic shift towards larger amplitudes (from 40.2 ± 13.8 µV to 53.3 ± 17.5 µV, p<0.001) and towards shorter latencies (from 425.0 ± 28.8 ms to 387.2 ± 30.3 ms, p<0.001) after six months, while CHEP areas were more constant over time. CONCLUSIONS: The present results show that systematic changes of CHEP amplitudes and latencies may occur over time. Possible reasons include seasonal differences in skin conductivity for heat and psychological effects. SIGNIFICANCE: CHEP areas seem to be more stable over time than amplitudes or latencies, however, it remains to be determined if CHEP areas differentiate between subjects with lesions of the nociceptive system and healthy controls as reliably as CHEP amplitudes.

Ewing sarcoma versus osteomyelitis: differential diagnosis with magnetic resonance imaging.

OBJECTIVE: To find and evaluate characteristic magnetic resonance imaging (MRI) patterns for the differentiation between Ewing sarcoma and osteomyelitis. MATERIALS AND METHODS: We identified 28 consecutive patients referred to our department for MRI (1.5 T) of an unclear bone lesion with clinical symptoms suggestive of Ewing sarcoma or osteomyelitis. MRI scans were re-evaluated by two experienced radiologists, typical MR imaging features were documented and a diagnostic decision between Ewing sarcoma and osteomyelitis was made. Statistical significance of the association between MRI features and the biopsy-based diagnosis was assessed using Fisher's exact test. RESULTS: The most clear-cut pattern for determining the correct diagnosis was the presence of a sharp and defined margin of the bone lesion, which was found in all patients with Ewing sarcoma, but in none of the patients with osteomyelitis (P < 0.0001). Contrast enhancing soft tissue was present in all cases with Ewing sarcoma and absent in 4 patients with osteomyelitis (P = 0.0103). Cortical destruction was found in all patients with Ewing sarcoma, 4 patients with osteomyelitis did not present any cortical reaction (P = 0.0103). Cystic or necrotic areas were identified in 13 patients with Ewing sarcoma and in 1 patient with osteomyelitis (P = 0.004). Interobserver reliability was very good (kappa = 1) in Ewing sarcoma and moderate (kappa = 0.6) in patients with osteomyelitis. CONCLUSIONS: A sharp and defined margin, optimally visualized on T1-weighted images in comparison to short tau inversion recovery (STIR) images, is the most significant feature of Ewing sarcoma in differentiating from osteomyelitis.

68Ga-DOTA-TOC uptake in neuroendocrine tumour and healthy tissue: differentiation of physiological uptake and pathological processes in PET/CT.

PURPOSE: We wanted to establish the range of (68)Ga-DOTA-TOC uptake in liver and bone metastases of patients with neuroendocrine tumours (NET) and to establish the range of its uptake in pancreatic NET. This would allow differentiation between physiological uptake and tumour-related somatostatin receptor expression in the pancreas (including the uncinate process), liver and bone. Finally, we wanted to test for differences in patients with NET, either treated or not treated with peptide receptor radionuclide therapy (PRRT). METHODS: In 249 patients, 390 (68)Ga-DOTA-TOC PET/CT studies were performed. The clinical indications for PET/CT were gastroenteropancreatic NET (194 studies), nongastroenteropancreatic NET (origin in the lung and rectum; 46 studies), NET of unknown primary (111 studies), phaeochromocytoma/glomus tumours (18 studies), and radioiodine-negative metastatic thyroid carcinoma (21 studies). RESULTS: SUVmax (mean ± standard deviation) values of (68)Ga-DOTA-TOC were 29.8 ± 16.5 in 162 liver metastases, 19.8 ± 18.8 in 89 bone metastases and 34.6 ± 17.1 in 43 pancreatic NET (33.6 ± 14.3 in 30 tumours of the uncinate process and 36.3 ± 21.5 in 13 tumours of the pancreatic tail). A significant difference in SUVmax (p < 0.02) was found in liver metastases of NET patients treated with PRRT. There were significant differences in SUVmax between nonmalignant and malignant tissue for both bone and liver metastases and for pancreatic NET including the uncinate process (p < 0.0001). At a cut-off value of 17.1 the specificity and sensitivity of SUVmax for differentiating tumours in the uncinate process were 93.6 % and 90.0 %, respectively (p < 0.0001). CONCLUSION: (68)Ga-DOTA-TOC is an excellent tracer for the imaging of tumours expressing somatostatin receptors on the tumour cell surface, facilitating the detection of even small tumour lesions. The noninvasive PET/CT approach by measurement of regional SUVmax can offer important clinical information to distinguish between physiological and pathological somatostatin receptor expression, especially in the uncinate process. PRRT does not significantly influence SUVmax, except in liver metastases of patients with NET.

Diagnostic value of software-based image fusion of computed tomography and F18-FDG PET scans in patients with malignant lymphoma.

AIM: The purpose of this study was to evaluate the accuracy of 2-deoxy-2-[fluorine-18]fluoro-D-glucose (FDG) positron emission tomography (PET), computed tomography (CT), and software-based image fusion of both modalities in the imaging of non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD). METHODS: 77 patients with NHL (n = 58) or HD (n = 19) underwent a FDG PET scan, a contrast-enhanced CT, and a subsequent digital image fusion during initial staging or followup. 109 examinations of each modality were evaluated and compared to each other. Conventional staging procedures, other imaging techniques, laboratory screening, and follow-up data constituted the reference standard for comparison with image fusion. Sensitivity and specificity were calculated for CT and PET separately. RESULTS: Sensitivity and specificity for detecting malignant lymphoma were 90% and 76% for CT and 94% and 91% for PET, respectively. A lymph node region-based analysis (comprising 14 defined anatomical regions) revealed a sensitivity of 81% and a specificity of 97% for CT and 96% and 99% for FDG PET, respectively. Only three of 109 image fusion findings needed further evaluation (false positive). CONCLUSION: Digital fusion of PET and CT improves the accuracy of staging, restaging, and therapy monitoring in patients with malignant lymphoma and may reduce the need for invasive diagnostic procedures.

Impaction bone grafting: a laboratory comparison of two methods.

In revision total hip replacement, bone loss can be managed by impacting porous bone chips. In order to guarantee sufficient mechanical strength, the bone chips have to be compacted. The aim of this study was to determine in an in vitro simulation whether the use of a pneumatic hammer leads to higher primary stability than manual impaction. Bone mass characteristics were measured by force and distance variation of a penetrating punch, which was lowered into a plastic cup filled with bone chips. From these measurements bulk density, contact stiffness, impaction hardness and penetration resistance were calculated for different durations of impaction. We found that the pneumatic method reached higher values of impaction hardness, contact stiffness and bulk density suggesting an increase in stability of the implant. No significant differences were found between the two different methods concerning the penetration resistance. The pneumatic method might reduce the risk of fracture in vivo, as force peaks are smaller and applied for a shorter period. Results from manual impaction showed higher variability and depend much on the experience of the surgeon. The pneumatic hammer is a suitable tool to standardise the impaction process.

Preliminary experience with (68)Ga-DOTA-lanreotide positron emission tomography.

AIM: Positron emission tomography (PET) of (68)Ga-radiolabelled (SST) somatostatin receptor (R) binding peptides has recently been evaluated in SSTR positive tumor patients. First promising results in lung and thyroid tumor patients with (111)In-DOTA-Lanreotide (DOTA-LAN) scintigraphy have been described. We report our first experience with (68)Ga-labeled DOTA-LAN. METHODS: Eleven patients (3 non small cell lung cancer [NSCLC], 3 small cell lung cancer [SCLC], 3 radioiodine negative thyroid cancer, 2 medullary thyroid cancer [MTC]) were investigated. After intravenous injection of 75-150 MBq (68)Ga-DOTA-LAN dynamic studies were acquired over the tumor site for the first 40 min with a dedicated PET scanner in 3 patients, and 2 partial body scans were acquired at 20 and 50 min p.i. in 2 patients. Whole body acquisitions at 90 min after injection were acquired in all 11 patients. Image reconstruction was performed by iterative reconstruction utilizing additional transmission scans for attenuation correction. Vital parameters were recorded during the PET study and up to 24 h p.i. Blood and urinary sampling was done up to 4 hr after tracer injection in 8 patients. PET results were compared to conventional imaging techniques (CIT), i.e. computed tomography (CT) and/or magnetic resonance imaging (MRI). In 5 patients, (68)Ga-DOTA-LAN was compared with 2-[(18)F]fluoro-2-deoxy-D-glucose ((18)F-FDG). RESULTS: After intravenous (i.v.) injection of (68)Ga-DOTA-LAN the radioactivity in the blood rapidly decreased to less then 20% of the injected dose (ID) within the first 20 min and further decreased to less than 9% ID after 4 h. A cumulative urinary excretion of (68)Ga-DOTA-LAN up to 29.2 + or - 13.2% ID at 4 h was found. No acute side effects were observed. Tumor sites were visualized already during the first min after injection. Comparison of positron emission tomography (PET) and CIT showed concordant results in 3/8 patients and partial concordant results in 5/8 patients with matched results for the primary/recurrent tumor, mediastinal lymph nodes, or adrenal gland metastases. Partial concordant results were seen for the lung, bone, liver and cervical lymph node metastases. Micronodular metastases of the lung and the cerebrum were not visualized by (68)Ga-DOTA-LAN PET. The maximal standardized uptake values of the lung and bone tumor lesions ranged from 6 to 8 g/ml at 90 min p.i.. CONCLUSIONS: (68)Ga-DOTA-LAN visualized the majority of tumor lesions. Further studies are required to assess the clinical value, and to obtain the best imaging protocol of this new PET SSTR tracer.

Comparison of (68)Ga-DOTA-Tyr(3)-octreotide and (18)F-fluoro-L-dihydroxyphenylalanine positron emission tomography in neuroendocrine tumor patients.

AIM: (68)Ga-DOTA-Tyr3-octreotide positron emission tomography ((68)Ga-DOTA-TOC PET) and (18)F-fluoro-L-dihydroxyphenylalanine PET ((18)F-DOPA PET) are emerging modalities for imaging of neuroendocrine tumors. This study reports our initial experiences with these two PET modalities on initial diagnosis, staging and restaging in NET patients. METHODS: Fifteen patients with NET underwent both (68)Ga-DOTA-TOC and (18)F-DOPA PET as well as computed tomography (CT). Image findings were compared on a patient-basis (pathological uptake: yes/no) as well as on a lesion-basis. Contrast-enhanced CT and histological follow-up served as gold standard. Furthermore, imaging results were matched with tumor marker levels and quantitative tracer uptake by the tumor lesions. RESULTS: When comparing (68)Ga-DOTA-TOC and (18)F-DOPA PET, each modality showed a sensitivity of 64% and a specificity of 100% on a patient-based analysis. (68)Ga-DOTA-TOC PET and (18)F-DOPA PET showed equal findings in 7 out of 15 patients and disagreement in 8 patients. (68)Ga-DOTA-TOC revealed more metastases than (18)F-DOPA PET in 6 patients, while (18)F-DOPA PET detected more metastases than (68)Ga-DOTA-TOC in 4 patients. By (68)Ga-DOTA-TOC PET, 208 malignant lesions were detected, while by (18)F-DOPA only 86 lesions were found, and in CT 124, respectively. CONCLUSIONS: (68)Ga-DOTA-TOC and (18)F-DOPA PET are useful tools in the detection and staging of NET lesions. Our initial results allow the conclusion that (68)Ga-DOTA-TOC PET may have a stronger clinical impact in NET patients, as it does not only offer diagnostic information, but is decisive for the further treatment management, i. e. PRRT, as well.

Individualized peptide-related-radionuclide-therapy concept using different radiolabelled somatostatin analogs in advanced cancer patients.

AIM: Over the last decade, somatostatin (SST) receptor (R)-positive tumors have been treated using either (90)Y-DOTA-TOC, (177)Lu-DOTA-TATE or (90)Y-DOTA-LAN/(177)Lu-DOTA-LAN, at the Innsbruck Medical University. This report presents data from the evaluation of the initial 100 patients receiving receptor mediated radionuclide therapy (PRRT) according to our protocol. METHODS: One-hundred patients with SSTR-positive tumors were treated (36 female, 64 male; mean age, 58 years; range, 13 to 84 years), including 68 patients with neuroendocrine tumors (NET), and patients with other non-neuroendocrine tumors, e.g. patients with radioiodine-negative thyroid carcinoma, refractory to conventional treatment modalities. Patients were selected based on high SSTR expression as assessed by (68)Ga-DOTA-TOC as first choice tracer for patients with NET, or (68)Ga-DOTA-LAN for patients with other tumor entities, or if the (68)Ga-DOTA-TOC PET was negative. Following positron emission tomography (PET), individual dosimetry was regularly performed using (111)In-labeled compounds. Therapy cycles were repeated every 10 weeks using either (90)Y-DOTA-TOC (3.7 GBq, 3-5 cycles) or (177)Lu-DOTA-TATE (7.4 GBq, 3-4 cycles). Thirteen patients received both and 5 patients even 3 different therapeutic compounds. Each patient received an amino acid solution (arginin, lysine) to reduce the kidney dose. Between the radioactive cycles a long-acting SST analog was applied. Dosages were individually adapted depending on several disease related factors. RESULTS: Overall, following PRRT partial remission (PR) was observed in 23 patients (23 %), minor remission (MR) in 10 (10 %), stable disease (SD) in 42 patients (42 %). Although 25 patients (25 %) showed progressive disease (PD), palliative care was provided in most of these patients. In the group treated with 90Y-DOTA-TOC, 12 patients showed PR, 3 MR, 32 SD and 13 had PD. In the group of patients treated with (177)Lu-DOTA-TATE, PR was observed in 15 patients, MR in 8, SD in 19 and PD in 13 patients. Severe side effects (WHO Grad 3 and 4) were seen in only 6 % of patients. Severe long-term nephrotoxicity was observed in none of the patients. These adverse reactions were especially seen in patients who were treated with high doses per cycle, in patients pre-treated with chemotherapy and in patients with low clinical performance. CONCLUSIONS: PRRT with differently labelled tracers (Y-90 or Lu-177) and different SST-analogs is generally well tolerated without serious side effects. These results favour the combined use of radiolabeled SST analogs providing a customized tumour targeting for size reduction and improvement of quality-of-life. Extended time intervals and reduced individual doses make sense in patients with advanced tumor stages, in case of moderate SSTR-expression, and in patients with higher age.