Staging of neuroendocrine tumours: comparison of [68Ga]DOTATOC multiphase PET/CT and whole-body MRI.

PURPOSE: In patients with a neuroendocrine tumour (NET), the extent of disease strongly influences the outcome and multidisciplinary therapeutic management. Thus, systematic analysis of the diagnostic performance of the existing staging modalities is necessary. The aim of this study was to compare the diagnostic performance of 2 whole-body imaging modalities, [(68)Ga]DOTATOC positron emission tomography (PET)/computed tomography (CT) and magnetic resonance imaging (MRI) in patients with NET with regard to possible impact on treatment decisions. MATERIALS AND METHODS: [(68)Ga]DOTATOC-PET/CT and whole-body magnetic resonance imaging (wbMRI) were performed on 51 patients (25 females, 26 males, mean age 57 years) with histologically proven NET and suspicion of metastatic spread within a mean interval of 2.4 days (range 0-28 days). PET/CT was performed after intravenous administration of 150 MBq [(68)Ga]DOTATOC. The CT protocol comprised multiphase contrast-enhanced imaging. The MRI protocol consisted of standard sequences before and after intravenous contrast administration at 1.5 T. Each modality (PET, CT, PET/CT, wbMRI) was evaluated independently by 2 experienced readers. Consensus decision based on correlation of all imaging data, histologic and surgical findings and clinical follow-up was established as the standard of reference. Lesion-based and patient-based analysis was performed. Detection rates and accuracy were compared using the McNemar test. P values <0.05 were considered significant. The impact of whole-body imaging on the treatment decision was evaluated by the interdisciplinary tumour board of our institution. RESULTS: 593 metastatic lesions were detected in 41 of 51 (80%) patients with NET (lung 54, liver 266, bone 131, lymph node 99, other 43). One hundred and twenty PET-negative lesions were detected by CT or MRI. Of all 593 lesions detected, PET identified 381 (64%) true-positive lesions, CT 482 (81%), PET/CT 545 (92%) and wbMRI 540 (91%). Comparison of lesion-based detection rates between PET/CT and wbMRI revealed significantly higher sensitivity of PET/CT for metastatic lymph nodes (100% vs 73%; P < 0.0001) and pulmonary lesions (100% vs 87%; P = 0.0233), whereas wbMRI had significantly higher detection rates for liver (99% vs 92%; P < 0.0001) and bone lesions (96% vs 82%; P < 0.0001). Of all 593 lesions, 22 were found only in PET, 11 only in CT and 47 only in wbMRI. The patient-based overall assessment of the metastatic status of the patient showed comparable sensitivity of PET/CT and MRI with slightly higher accuracy of PET/CT. Patient-based analysis of metastatic organ involvement revealed significantly higher accuracy of PET/CT for bone and lymph node metastases (100% vs 88%; P = 0.0412 and 98% vs 78%; P = 0.0044) and for the overall comparison (99% vs 89%; P < 0.0001). The imaging results influenced the treatment decision in 30 patients (59%) with comparable information from PET/CT and wbMRI in 30 patients, additional relevant information from PET/CT in 16 patients and from wbMRI in 7 patients. CONCLUSION: PET/CT and wbMRI showed comparable overall lesion-based detection rates for metastatic involvement in NET but significantly differed in organ-based detection rates with superiority of PET/CT for lymph node and pulmonary lesions and of wbMRI for liver and bone metastases. Patient-based analysis revealed superiority of PET/CT for NET staging. Individual treatment strategies benefit from complementary information from PET/CT and MRI.

Correlation of preoperative magnetic resonance imaging of peritoneal carcinomatosis and clinical outcome after peritonectomy and HIPEC after 3 years of follow-up: preliminary results.

PURPOSE: In patients with peritoneal carcinomatosis, cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) is an evolving approach with curative intention. Previous studies indicate a correlation between preoperative magnetic resonance imaging (MRI) and surgical findings regarding the extent of peritoneal carcinomatosis. The aim of this study was to assess retrospectively whether preoperative MRI can predict the outcome and is therefore a suitable tool for patient selection. MATERIALS AND METHODS: Fifteen patients with laparoscopically proven peritoneal carcinomatosis were preoperatively examined using a 1.5-T whole-body MRI system. Results were correlated with surgical exploration. Follow-up was done by contrast-enhanced abdominal computed tomography and, if suspicious for recurring disease, laparoscopy or laparotomy. Survival time and interval to recurring disease were correlated with the preoperative peritoneal carcinomatosis index (PCI) on MRI (Spearman's rank correlation). RESULTS: In five patients radical resection could not be achieved (PCI 34 ± 6.9); survival time was 78.2 ± 54.1 days. In seven patients recurring disease was found 430 ± 261.2 days after initial complete cytoreduction (PCI 11.6 ± 6.9); survival time was 765.9 ± 355 days. Two patients are still alive after 3 years. Two patients with initially complete cytoreduction are without recurring disease after 3 years (PCI 5 and 12). One patient was lost for follow-up. CONCLUSIONS: Results of the preoperative MRI correlate well with the surgical PCI, postoperative resection status, and survival time. MRI might be a suitable technique for patient selection when considering peritonectomy and HIPEC. In our patients the outcome seems to correlate well with the extent of peritoneal carcinomatosis found by the preoperative MRI.

FDG-PET/CT-guided biopsy of bone metastases sets a new course in patient management after extensive imaging and multiple futile biopsies.

A 73-year-old man with a history of prostate and bladder carcinoma and persistent back pain was diagnosed by MRI with multiple vertebral metastases including a compression fracture of T7. He received radiotherapy for pain relief and for vertebral instability with incipient spinal stenosis, but additional targeted systemic therapy was intended. Therefore, multiple attempts at minimally invasive and open biopsies for histological characterisation of the bone metastases were performed, but failed to provide a conclusive specimen, although CT, MRI and bone scintigraphy were used for biopsy planning. Only histopathological analysis of an (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET)/CT-guided additional biopsy at a site with high metabolic activity yielded the final diagnosis of bone metastases of a neuroendocrine small cell cancer of unknown origin; hence, the patient had a third malignancy requiring a different therapy regimen and diagnostic work-up.

Integrated FDG-PET/CT for detection, therapy monitoring and follow-up of granulocytic sarcoma. Initial results.

AIM: Granulocytic sarcomas (GS) are rare extramedullary manifestations of myeloid or lymphoblastic leukaemia. Laboratory examinations are of limited use for diagnosis of extramedullary disease. Radiological imaging based on morphology is challenging. To date, the possible role of FDG-PET/CT as a method for combined metabolic and morphologic imaging is unclear. We present a series of 10 patients to evaluate the potential role of FDG-PET/CT in the management of GS. PATIENTS, MATERIALS, METHODS: A retrospective evaluation of 18 FDG-PET/CT exams in 10 patients with histologically proven GS was performed. All scans included a contrast enhanced CT. The FDG uptake of GS was analyzed and the sensitivity of lesion detection was compared to PET and CT alone. The changes in FDG uptake after therapy were compared to morphological changes detected by CT and follow-up / clinical outcome. RESULTS: 52 untreated or recurrent GS lesions were detected by FDG-PET/CT and all showed an increased FDG uptake with a mean SUVmax and SUVavg of 5.1 and 3.4, respectively. GS was multifocal in 8/10 patients. Combined PET/CT avoided 5 false positive findings compared to PET alone and 13 false negative findings and 1 false positive compared to CT alone. Changes in FDG uptake after therapy correlated with clinical outcome and were more reliable than CT assessment alone. PET/CT identified recurrent GS in 3 patients. CONCLUSION: Viable GS are FDG-avid. Using this metabolic information and morphologic CT criteria, combined FDG-PET/CT was more accurate in lesion detection than FDG-PET or CT alone. Changes in FDG uptake after therapy might be a useful additional parameter for therapy monitoring. Therefore, FDG-PET/CT appears to be a promising diagnostic and monitoring tool in the management of patients with GS.

[Selection criteria for peritonectomy with hyperthermic intraoperative chemotherapy (HIPEC) in peritoneal carcinomatosis]. / Selektion zur Peritonektomie mit hyperthermer intraoperativer Chemotherapie (HIPEC) bei Peritonealkarzinose.

BACKGROUND: Cytoreductive peritonectomy with hyperthermic intraoperative chemotherapy (HIPEC) is an established therapy for patients with gastrointestinal, gynaecological metastasised peritoneal carcinomatosis as well as primary peritoneal carcinomatous tumours. METHODS: On the basis of a literature review and our personal experience, selection criteria for peritonectomy are discussed. RESULTS: Computed tomography (CT) scans and diagnostic laparoscopy are not sufficient for the diagnosis of peritoneal carcinomatosis. The combination of fluorodeoxyglucose positron emission tomography (FDG-PET) and CT seems to be the most reliable diagnostic imaging method. In our institution, all patients undergo PET / CT prior to peritonectomy. CONCLUSION: The PET / CT scan may play an important role in forecasting the operability of patients with peritoneal carcinomatosis.

[Detection of bone metastasis of prostate cancer - comparison of whole-body MRI and bone scintigraphy]. / Nachweis ossärer Metastasen des Prostatakarzinoms - Vergleich der Leistungsfähigkeit der Ganzkörper-MRT und der Skelettszintigrafie.

PURPOSE: Prostate cancer continues to be the third leading cancer-related mortality of western men. Early diagnosis of bone metastasis is important for the therapy regime and for assessing the prognosis. The standard method is bone scintigraphy. Whole-body MRI proved to be more sensitive for early detection of skeletal metastasis. However, studies of homogenous tumor entities are not available. The aim of the study was to compare bone scintigraphy and whole-body MRI regarding the detection of bone metastasis of prostate cancer. MATERIALS AND METHODS: 14 patients with histologically confirmed prostate cancer and a bone scintigraphy as well as whole-body MRI within one month were included. The mean age was 68 years. Scintigraphy was performed using the planar whole-body technique (ventral and dorsal projections). Suspect areas were enlarged. Whole-body MRI was conducted using native T 1w and STIR sequences in the coronary plane of the whole body, sagittal imaging of spine and breath-hold STIR and T 1w-Flash-2D sequences of ribs and chest. Bone scintigraphy and whole-body MRI were evaluated retrospectively by experienced radiologists in a consensus reading on a lesion-based level. RESULTS: Whole-body MRI detected significantly more bone metastasis (p = 0.024). 96.4 % of the demonstrated skeletal metastases in bone scintigraphy were founded in whole-body MRI while only 58.6 % of the depicted metastases in MRI were able to be located in scintigraphy. There was no significant difference regarding bone metastasis greater than one centimeter (p = 0.082) in contrast to metastasis less than one centimeter (p = 0.035). Small osteoblastic metastases showed a considerably higher contrast in T 1w sequences than in STIR imaging. Further advantages of whole-body MRI were additional information about extra-osseous tumor infiltration and their complications, for example stenosis of spinal canal or vertebral body fractures, found in 42.9 % of patients. CONCLUSION: Whole-body MRI using native STIR and T 1w sequences is superior to bone scintigraphy for the detection of small bone metastasis of prostate cancer. Simultaneous clarification of associated complications demonstrates further advantages.

[Cost considerations for whole-body MRI and PET/CT as part of oncologic staging]. / Kostenüberlegungen zur Ganzkörper-MRT und PET-CT im Rahmen des onkologischen Stagings.

PURPOSE: The aim of this study was to evaluate and discuss economic aspects of whole-body MRI and PET/CT in oncologic staging. Considerations from the perspective of the health care system, the radiologist, and the patients are presented. MATERIALS AND METHODS: Costs of both whole-body techniques are compared with the conventional radiologic diagnostic recommendations of the AWFM (Arbeitsgemeinschaft Wissenschaftlich Medizinischer Fachgesellschaften) in oncologic staging of the five most frequent tumor entities. Temporal and monetary aspects are calculated. Invasive, endoscopic, and endosonographic techniques are regarded as essential and cannot be replaced by other techniques. Thus only the minimal potential for cost reduction is quantified. RESULTS: In the German system there is no cipher to correctly balance whole-body MRI and PET/CT. Using the frequently applied ciphers 5700-5730 and 5378, 5489 (factor 1.0) total costs were 440.45 euros, and adding the cipher for additional series 545.37 euros (60 min examination time) for whole-body MRI and 774.74 euros (879.66 euros) (60/90 min examination time) for whole-body PET/CT. Using the common factor 1.8 costs were 981.66 and 1583.38 euros. On the basis of a simple full cost analysis total costs of whole-body PET/CT were higher than of whole-body MRI by a factor of about 2.0 (about 1123 vs 575 euros). There were substantial monetary and temporal differences between tumor entities. In extended bronchial carcinoma 375.32 euros and 55 min can be saved using whole-body MRI in comparison to conventional recommended techniques and using whole-body PET/CT 88.14 euros and 45 min. In tumor entities of lower stages with thus less essential radiologic diagnostics the potential for cost reduction is substantially lower. CONCLUSION: Whole-body imaging techniques make it possible to reduce the number of necessary separate radiologic examinations and thus time in oncologic staging. A substantial reduction of health care costs seems to be possible in many tumor entities but differences between different tumor entities are decisive.

Comparison of 11C-choline-PET/CT and whole body-MRI for staging of prostate cancer.

UNLABELLED: Aim of this study was to compare the diagnostic accuracy of positron emission tomography and computed tomography with (11)C-Choline (Cho-PET/CT) and whole body magnetic resonance imaging (WB-MRI) for diagnostic work-up of prostate cancer. PATIENTS, METHODS: We evaluated retrospectively 42 patients with untreated prostate cancer (n = 17), or increasing levels of prostate-specific antigen (PSA) after curative therapy (n = 25) who had been investigated by both Cho-PET/CT and WB-MRI. MRI, CT, and PET images were separately analyzed by experienced radiologists or nuclear medicine experts, followed by consensus reading. Validation was established by histology, follow-up, or consensus reading. RESULTS: 88/103 detected lesions were considered as malignant: 44 bone metastases, 22 local tumor, 15 lymph node metastases, 3 lung, and 3 brain metastases. One further lesion was located in the adrenal gland, which was a second tumor. Overall sensitivity, specificity and accuracy for Cho-PET/CT were 96.6%, 76.5%, and 93.3%, resp., and for WB-MRI 78.4%, 94.1%, and 81.0%, resp. 3 vertebral metastases had initially been missed by Cho-PET/CT and were found retrospectively. MRI identified 2 bone metastases and 1 lymph node metastasis after being informed about the results of Cho-PET/CT. CONCLUSIONS: Cho-PET/CT and WB-MRI both presented high accuracy in the detection of bone and lymph node metastases. The strength of MRI is excellent image quality providing detailed anatomical information whereas the advantage of Cho-PET/CT is high image contrast of pathological foci.

Value of contrast-enhanced multiphase CT in combined PET/CT protocols for oncological imaging.

To evaluate the additional value of contrast-enhanced multiphase CT in comparison with low-dose non-contrast CT in combined positron emission tomography (PET)/CT protocols for oncological imaging, we retrospectively analysed 100 patients with different malignant tumours. All patients underwent a PET/CT consisting of a multiphase CT protocol including a low-dose non-enhanced attenuation scan and an arterial and portal-venous contrast-enhanced scan followed by a whole-body PET. PET/CT studies were analysed by different categories to determine the added value of contrast-enhanced CT. The additional value was defined as new information provided by diagnostic CT and not available from the low-dose CT, resulting in change of PET/CT interpretation. The results were validated either by histopathology or by clinical-radiological follow up at > or =6 months. The clinical impact was evaluated with respect to changes in patient management. Diagnostic multiphase CT was of additional value in 52 out of 100 patients with 85 suspected lesions. In 40 out of 100 patients, no additional value could be detected. Eight patients were excluded due to inconclusive diagnosis in both methods including fusion. The analysis showed the greatest benefit of diagnostic CT in the categories localization of pathological fluorodeoxyglucose (FDG) uptake and precise tumour delineation, changing PET/CT interpretation in 42% and 31% of patients, respectively. The benefit of diagnostic CT was influenced by the tumour type demonstrating the highest impact in gastrointestinal, lung and neuroendocrine tumours. Diagnostic CT changed clinical management in 21 patients (21%). Diagnostic multiphase CT as part of the combined PET/CT protocol has the potential to provide considerable additional value in specific clinical conditions with resultant change of management in a substantial proportion of patients.

[Evaluation of different breathing and contrast-protocols concerning quality and alignment in 18F-FDG PET/CT]. / Vergleich verschiedener Atem- und Kontrastmittelprotokolle bezüglich Bild- und Koregistrierungsqualität bei 18F-FDG-PET/CT-Untersuchungen.

PURPOSE: The purpose of this study was to establish a reliable and simple parameter for alignment evaluation and the evaluation and optimization of state-of-the-art contrast-enhanced examination protocols for (18)F FDG-PET/CT. MATERIALS AND METHODS: 44 consecutive patients were referred to 4 examination protocols. Group A and B underwent single-phase, contrast-enhanced CT (90 s delay) performed either during free shallow breathing (FA; group A) or normal expiration (NormExp; group B). Groups C and D underwent arterial and portal venous multiphase examinations performed during FA (group C) or during NormExp (group D) followed by a low-dose CT scan for attenuation correction. Organ displacement in the cranio-caudal direction was correlated with a 3D-vectorial shift. For alignment evaluation discrepancies with respect to size and liver location, the spleen and kidneys were calculated. Additionally, the groups were compared with regard to the presence of CT artifacts. RESULTS: Cranio-caudal organ shift and 3D-vectorial shift showed a high correlation (r > 0.8). Single-phase CT scans performed during NormExp yielded better image quality (p < 0.001) and alignment (p < 0.01 for liver, spleen and right kidney) than those performed during FA. Differences in organ size did not differ during FA and NormExp. Depending on the evaluated organ, breathing and contrast protocol misalignment was in the cranio-caudal direction 0-27 mm (mean: 6.8; standard deviation: +/- 4.9) in multiphase CT compared to 0 - 11 mm (mean: 4.5 +/- 2.3) in single-phase examinations. CONCLUSION: 1. Organ shift in the cranio-caudal direction is a good and simple parameter for alignment evaluation. 2. Alignment and CT quality are best in expiration protocols. 3. Despite comparatively low alignment quality, integrated multiphase CT examinations show acceptable quality and alignment.

[Significance of PET and integrated PET/CT in the diagnostics of occult primary tumors]. / Stellenwert von PET und integriertem PET/CT in der Diagnostik des CUP-Syndroms.

BACKGROUND: In the last years (18)F-FDG-positron-emission-tomography (PET) worked satisfactorily as helpful auxiliary method in order to verify recurrency of head and neck tumors and to detect primary tumors in case of CUP syndrome especially when CT and MR imaging failed to identify the tumor accurately. Fusion of FDG hypermetabolism in PET scan and anatomical structures is achieved by integrating positron emission tomography with CT and provides improvement also in case of CUP syndrome. This retrospective study shows 47 patients with neck metastases where PET or PET/CT helped to detect primary tumor site. PATIENTS: In a retrospective investigation 49 PET studies of 47 patients with CUP syndrome were analyzed. RESULTS: 9 cases had positive PET findings, 1 case false-positive. 5 cases were false-negative. In 40 PET studies there couldn't be found any sign of suspicious FDG hypermetabolism. CONCLUSION: PET and PET/CT deliver a certain improvement in localization of primary tumor site and therapeutical strategy.