Liver adenomatosis mimics metastatic liver involvement on FDG-PET/ CT.

BACKGROUND: Liver adenomatosis is a very rare disease. In the literature, we were able to find only two case reports documenting the appearance of this disease on PET/CT with 18F-fludeoxyglucose (FDG-PET/CT). CASE: Numerous liver foci were detected during sonography in a 52-year-old female patient with uncharacteristic pain in the epigastrium without oncological history, with negative oncomarkers and without clinical signs of generalized neoplasia. Complementary MRI examination expressed the suspicion of metastatic origin of the foci, and FDG-PET/CT was indicated in order to identify the primary tumour and assess the extent of the disease. A whole-body FDG-PET/CT examination showed multiple (> 20) markedly hypermetabolic liver foci with 3-20 mm in diameter, reaching a relative accumulation of SUVBWmax = 13, together with several ametabolic cysts; elsewhere in the scope of the examination, focally pathologically increased metabolic activity was not evident. Subsequently, the patient underwent a biopsy targeted at one of the hypermetabolic liver foci with the finding of HNF 1A inactivated variant of hepatocellular adenoma; primary or secondary malignancy was not demonstrated. Considering the histological findings and the large number of liver foci, the final diagnosis of liver adenomatosis was set. The patient remains under continuous observation. CONCLUSION: Adenomatous foci were markedly hypermetabolic during FDG-PET/CT examination and could not be distinguished from tumour metastases by this method. Our finding is consistent with two other observations we were able to find in the literature.

Durable Complete Response of Colorectal Cancer Metastasis after Biochemotherapy.

BACKGROUND: Resection of the metastatic site is indicated but not always possible in patients with metastatic colorectal cancer (mCRC) who achieve a partial or complete response (CR) to induction systemic treatment. CR after systemic treatment alone is uncommon, and even patients with radiologic CR after induction chemotherapy harbour persistent macroscopic or microscopic residual disease in more than 80% of cases. Occasionally, some metastatic lesions disappear radiologically but others persist after induction systemic treatment. The indication and extent of metastasectomy in these situations is controversial, especially regarding sites with completely regressed metastases. CASE: This case report describes a patient with mCRC who achieved a long-term response after biochemotherapy and incomplete metastasectomy. One of the known liver lesions could not be removed due to its disappearance after induction biochemotherapy with FOLFOX and bevacizumab. Further adjuvant chemotherapy using the FOLFOX regimen was administered postoperatively. The patient has been meticulously followed by radiology including repeated positron emission tomography/computed tomography and magnetic resonance scans, clinical examination and tumour markers. No recurrence of cancer has been detected after a follow-up of 5 years. RESULTS AND CONCLUSION: CR to systemic treatment is uncommon, but this case report demonstrates that it can be durable in patients with colorectal cancer and liver metastases. This case report indicates that some patients with mCRC can be cured with systemic therapy only, challenging the prevailing paradigm of mCRC therapy.Key words: colorectal cancer - metastasis - chemotherapy - molecular targeted therapy - diagnostic imaging.

Endovascular treatment of infected aortic aneurysms.

OBJECTIVE: To report on the short- and long-term outcomes of patients with primary infected aortic aneurysm (IAA) treated by stent graft (SG) in two centers. MATERIAL AND METHOD: Over a period of 15 years, 32 patients with IAA underwent endovascular treatment. None had undergone previous aortic surgery. The causal relationship was gastrointestinal infection in 9 patients (28%), endovascular diagnostic/therapeutic procedures/resuscitation in 6 (19%), wound infection after previous surgeries in 5 (16%), urinary infection in 4 (13%), urology or gastroenterology procedures in 3 (9%), pancreatitis in 2 (6%), endocarditis in 1 (3%) and phlebitis in 1 (3%) patient. We implanted 11 bifurcated, 10 tubular thoracic, 4 aorto-uni-iliac, 4 tubular abdominal and 1 iliac SG. Two other surgeries were hybrid procedures. RESULTS: The etiological agent was identified in 28 (88%) patients. Twenty-six (81%) patients survived the 30-day postoperative period. Sixteen (50%) survived to 1-year follow-up and 13 (40.6%) survived to 3-year follow-up. Three patients have survived for less than 1 year and a further 3 for less than 3 years, so far. Among patients with aneurysms situated in central parts of the thoracic and infrarenal aorta there was a better death/survival ratio than among patients with a proximal or distal aneurysm location. CONCLUSION: The implantation of a SG may be an alternative to open surgery in selected groups of patients with primary IAA. Aneurysms of the central part of the thoracic or abdominal aorta have a more favorable prognosis with endovascular treatment.

PET/CT significance for planning radiotherapy of head and neck cancer.

The combination of positron emission tomography and computed tomography (PET/CT) offers metabolic mapping in addition to anatomic information of the primary lesion, nodal and distant metastases in patients with head and neck tumors, and may be therefore beneficial for radiotherapy planning. The aim of our study was to evaluate benefits of combined PET and CT imaging for staging and target volume delineation in this group of patients.Fifty three patients (40 men and 13 women) with confirmed advanced, inoperable or non-radically operated head and neck cancer were assessed based on the results of PET/CT as well as standard diagnostic examinations. All patients were subsequently treated with intensity modulated radiotherapy (IMRT) with simultaneous integrated boost (SIB) of 6 MV X-rays. There was an agreement between the standard examinations results and results of PET/CT in 30 cases. In 23 cases there was disagreement either in tumor size, nodal involvement or presence of distant metastases. Results of the tumor size assessment differed significantly in 5 cases. There was no agreement found in nodal involvement in 10 cases. The cancer confirmed by standard examination was not found by PET/CT in 2 cases; 3 PET/CT positive findings were not confirmed by standard examinations. In 3 patients PET-CT revealed new distant metastatic disease. Based on PET/CT assessment we changed treatment strategy and applied potentially curative dose of radiotherapy to previously undiscovered regions in 9 patients. We decided to change the treatment intent in 3 cases and only palliative treatment was applied. Based on our experience and the literature review, PET/CT may be considerable contribution to the standard diagnostic procedures in approximately one third of cases.

Current trends in the diagnosis of vascular prosthesis infection.

Early diagnosis of an infected vascular prosthesis, a potentially life-threatening disease, is a precondition of adequate treatment. The most frequently used diagnostic imaging method is computer tomography. Non-acute infections caused by low grade agents may pose a challenge with ambiguous CT-images and other ancillary imaging methods are used for these cases, each offering different levels of diagnostic sensitivity. These methods come from the fields of radiology (magnetic resonance imaging - MRI) and nuclear medicine studies using labelled leukocytes (111In or 99mTc HMPAO), 99mTc labelled antigranulocyte antibodies, 67Ga-citrate or labelled antibiotics (99mTc-ciprofloxacin) or avidin in combination with 111In-biotin. Positron emission tomography (PET) or hybrid PET/CT using 18F-FDG are becoming increasingly popular. The authors of this review article point out the diagnostic potential of the different methods and current trends, including the possibilities of microbiological demonstration of the agent, as well as their potential position in the diagnostic algorithm.

Contribution to FDG-PET/CT diagnostics and post-operative monitoring of patients with mycotic aneurysm of the thoracic aorta.

Bacterial infection of the aorta is a life threatening condition calling for timely diagnostics and therapy. In the short communication presented here, the authors offer a case report on a patient of 70 years of age with aneurysm of the descending aorta caused by salmonella. The advantages of a new diagnostic hybrid modality are demonstrated and also the possibility of using it in the course of long-term monitoring of patients.

[Contribution to diagnostics of vascular prosthesis infections]. / Príspevek k diagnostice infekce cévní protézy.

Vascular prosthesis infection is a life-threatening complication in 0.5-5% of cases. Early and reliable diagnosis is a necessity for adequate treatment. Computed tomography (CT) is the gold standard diagnostic method used world-wide with excellent results, but in cases of advanced graft infection. Low grade infections in non-acute patients are a diagnostic challenge requiring a new method with good diagnostic accuracy. The authors describe diagnostic accuracy of currently available methods.

Diagnostics of "non-acute" vascular prosthesis infection using 18F-FDG PET/CT: our experience with 96 prostheses.

INTRODUCTION: Vascular prosthesis infection (VPI) is a life-threatening complication that occurs in 0.5-5% of prostheses. Low-grade infections in non-acute patients are a diagnostic challenge requiring a new method with good diagnostic accuracy. The aim of this work was to define the accuracy of (18)F-FDG PET/CT in these settings and to identify essential parameters of the evaluation. MATERIAL AND METHODS: PET/CT was performed prospectively in 76 consecutive patients with a total of 96 vascular prosthetic grafts in which infection was suspected. PET/CT scans were analysed in terms of the presence and intensity of focal and diffuse FDG uptake, the presence of an anastomotic pseudoaneurysm, the presence of an irregular boundary of infiltration, a combination of these, and the uptake ratio between the graft and blood background. The gold standard was based on operative/histopathological finding or a clinical follow up of >6 months. RESULTS: Among the various assessed parameters only focal FDG uptake and an irregular graft boundary were significant predictors of VPI. Focal intense FDG uptake together with an irregular boundary of the lesion on CT scan predicted VPI with 97% probability, while smooth lesion boundaries and no focal FDG uptake predicted a probability of VPI of less than 5%. Even in lesions with nondiagnostic inhomogeneous focal FDG uptake (18/96) an irregular boundary effectively helped in decision-making with a probability of 28% (smooth) or 77% (irregular) for VPI. CONCLUSION: PET/CT gave reliable results with an accuracy >95% in 75% of prostheses. PET/CT can identify those prostheses (25% of prosthesis) for which its diagnostic accuracy is diminished to 70-75%. In our series PET/CT was an excellent diagnostic modality for suspected VPI.

[The outcome of whole-body FDG-PET examination predicts the future of patients with diffuse large-cell lymphoma in the use of both intermediary staging and at the end of standard chemotherapy]. / Výsledek celotelového FDG-PET vysetrení predikuje osud nemocných s difuzním velkobunecným lymfomem jak pri pouzití v intermediárním stagingu, tak pri pouzití na konci standardní chemoterapie.

AIM: Response to the therapy is one of the most valuable prognostic factors. The response evaluation is performed by computer tomography as a standard tool. The introduction of FDG-PET whole body imaging allows to discriminate viable tumor and fibrotic changes in structural abnormalities. METHODS: We have performed retrospective analysis of 96 patients with diagnosis of diffuse large B-cell lymphoma (1999-2004) who were treated by anthracyclin based chemotherapy and FDG-PET was performed as a part of intermediate restaging (after 2nd-4th cycle, 69 patients) or/and at the end of standard chemotherapy (68 patients). RESULTS: The progression free survival (PFS) and overall survival (OS) at 3 years were the endpoints. Median follow up was 30 months. The PFS and OS resp. for PET negative pts at intermediate restaging was 80.7% and 97.6% compared to the 50.5% and 71.5 % resp. for PET positive patients. The relapse risk and death risk for PET positive patients was 4.8 and 6.4 resp. The PFS and OS resp. for PET negative pts at the end of chemotherapy was 81.7% and 94.7% resp. compared to the 29.4% (p < 0.0001) and 57.5% (p < 0.0001) resp. for PET positive patients. The relapse risk and death risk for PET positive patients was 7.0 and 12.9 resp. Predictive value of PET at intermediate as well at the end restaging was observed in IPI low group as well IPI high risk subgroups for both PFS and OS, except OS in high risk subgroup at intermediate restaging. CONCLUSION: The current analysis confirms predictive PET value for patients with DLBCL at intermediate as well at the end restaging. The question if and how to use the PET findings for tailoreing of therapy remains to be answered in prospective trials.

Role of FDG-PET and PET/CT in the diagnosis of prolonged febrile states.

PURPOSE: The role of FDG-PET and PET/CT in patients whose main symptom is prolonged fever has not yet been defined. We addressed this topic in a retrospective study. METHODS: A total of 124 patients (referred between May 2001 and December 2004) with fever of unknown origin or prolonged fever due to a suspected infection of a joint or vascular prosthesis were included in the study. The patients underwent either FDG-PET or FDG-PET/CT scanning. Sixty-seven patients had a negative focal FDG-PET finding; in this group the method was regarded as unhelpful in determining a diagnosis, and no further investigation was pursued. We tried to obtain clinical confirmation for all patients with positive PET findings. RESULTS: Fifty-seven (46%) patients had positive FDG-PET findings. In six of them no further clinical information was available. Fifty-one patients with positive PET findings and 118 patients in total were subsequently evaluated. Systemic connective tissue disease was confirmed in 17 patients, lymphoma in three patients, inflammatory bowel disease in two patients, vascular prosthesis infection in seven patients, infection of a hip or knee replacement in seven patients, mycotic aneurysm in two patients, abscess in four patients and AIDS in one patient. In eight (16%) patients the finding was falsely positive. CONCLUSION: FDG-PET or PET/CT contributed to establishing a final diagnosis in 84% of the 51 patients with positive PET findings and in 36% of all 118 evaluated patients with prolonged fever.

[Comparison between conventional imaging methods and positron emission tomography in the treatment of Hodgkin's lymphoma]. / Srovnání konvencních zobrazovacích metod a pozitronové emisní tomografie v lécbe Hodgkinova lymfomu.

BACKGROUND: Positron emission tomography with fluorodeoxyglucose offers the possibility to differentiate between lymphoma and nonmalignant tissue. The aim of this retrospective study was a comparison between PET and conventional imaging methods before and after therapy--during the follow-up of Hodgkin's lymphoma. METHODS AND RESULTS: The group of 94 patients with HL underwent 180 PET examinations. PET was performed in 53 patients during initial staging of lymphoma. 119 PET studies were undertaken after therapy during the follow-up. Eight patients underwent PET examination for suspected relapse or progression of HL. Findings were verified by a follow-up in all patients and by histology in selected cases. PET and conventional imaging methods were positive in 42 of 53 (79%) patients in initial stages. The stage of the disease was changed in 7 patients (13.2%) according to PET. False negative findings were recorded in three cases and false positive in one case. Sensitivity of PET was higher compared to conventional imaging methods (92% vs 87%) in initial staging. PET and conventional imaging methods were identical in 94.9% of cases during the follow-up (77.3% negative and 17.6% positive findings). Sensitivity of PET during the follow-up after therapy was higher compared to conventional imaging methods (99.1% vs 95.7%). PET was positive in all eight cases in relapse/progression of HL and conventional imaging methods were positive in only seven of eight cases. CONCLUSIONS: PET is a more sensitive method in initial staging, during follow-up and in suspected progression/relapse of HL than conventional imaging methods and it should be included into routine examination methods of HL.

[A surgeon's view on the importance of positron emission tomography--PET (with emphasis on lung neoplasms)]. / Pohled chirurga na význam pozitronové emisní tomografie--PET (se zamerením na plicní nádorové postizení).

OBJECTIVE: PET became a successful method in preoperative evaluation of patients with cancer. We question whether PET scan can answer critical surgeons' requests such as distinguish benign and malign lesions, evaluation of cancer dissemination, evaluation of the pleural effusions, and also to detect early cancer recurrence. METHODS: Between September 1999 and December 2001, 39 patients underwent a PET scan and we evaluated its benefit in further treatment of patients. Standard PET techniques were used. RESULTS: In 20 patients (52%) results of PET scan were in correlation of clinical diagnosis and stage of cancer disease, partial difference between FDG-PET and clinical diagnosis was in 8 patients (20%), next treatment was changed in 11 patients (28%). CONCLUSION: We conclude, that dedicated PET could be valuable tool in the diagnosis and staging of cancer disease, especially in verifying cancer dissemination, recurrence of the cancer. PET scan can be misleading in evaluation of the mediastinal lymphnodes and pleural effusions.

[Predictive features of positron emission tomography after two cycles of induction therapy in malignant lymphoma]. / Prediktivní vlastnosti pozitronové emisní tomografie provádené po druhém cyklu indukcní terapie maligních lymfomu.

BACKGROUND: Positron emission tomography (PET) is a modern functional imaging method, recently introduced to clinical oncology. The aim of our study was the evaluation of prognostic value of PET performed in malignant lymphoma patients after two cycles of chemotherapy. METHODS AND RESULTS: From 9/99 to 11/00 PET was performed in 37 patients with malignant lymphoma (9x m. Hodgkin, 21x HG + IG-NHL, 7x LG-NHL; 26x new diagnosis, 11x relaps of disease). Freedom from progression interval (FFP) and overall survival (OS) were evaluated. Attenuation corrected PET imaging was done by dedicated ECAT EXACT PET scanner from base of the skull to the upper thighs 1 hour after intravenous administration of 18-FDG (7.6 +/- 1.3 MBq/kg). Statistical analysis was done using Kaplan-Meier method. Significance of differences between groups was determined by log-rank test on the level of 5%. After the induction therapy, 30 patients were in complete remission, 3 patients in partial remission and in 4 cases progression of disease were observed. Progression of disease was seen in 4 patients. Median follow up of living patients was 7 months (1-13 months) from the end of therapy. Progression, resp. relapse of disease occurred in 13 patients during this period, two patients died. PET performed after the second course of therapy was positive in 18 patients and negative in 19 patients. Two progressions, resp. relapses of disease were documented in PET-negative group and 11 in PET-positive group. FFP was significantly different in PET positive and PET negative groups (p < 0.05). The negative and positive predictive values of PET for malignant lymphoma relapse or progression were estimated 89%, 63% respectively. CONCLUSION: Regardless the short follow-up period, our preliminary results reflect very good prognostic value of PET performed after the second course of chemotherapy in malignant lymphoma patients.

[Positron emission tomography (PET) in patients with malignant lymphomas--indications for the method as presented in case reports]. / Vyuzití pozitronové emisní tomografie (PET) u nemocných s maligními lymfomy--indikace metody prezentované formou kazuistických sdelení.

Positron emission tomography is a modern functional imaging method recently available also in the Czech Republic. The authors try to present indications of this method in the form of case-histories of patients with malignant lymphomas.

Metabolic characterisation of solitary pulmonary nodules by positron emission tomography with FDG--preliminary report.

BACKGROUND: In the past some authors evaluated FDG-PET as a powerful tool for non-invasive assessment of malignancy of solitary pulmonary nodules (SPN). The aim of this paper is to verify the performance of positron emission tomography with fludeoxyglucose (FDG-PET) in SPN in the conditions of the Czech Republic during the first 16 months of the operation of the PET Centre Prague. MATERIAL AND METHODS: The group of 22 patients with 23 SPN was investigated by dedicated PET scanner due to inconclusive CT scan. Micromorphological confirmation was available in 61%; follow-up (median = 12 months) concerned the other 39% SPN. RESULTS: PET was clearly positive in 11 nodules, all were malignant according to micromorphological assessment. PET was completely negative in 10 nodules, 3 of them were micromorphologically evaluated as benign, the other 7 nodules were followed up without any signs of malignancy. In two cases, PET revealed enhanced glucose consumption, but the pattern was not typical for malignancy. These cases were considered as bronchopneumonia, but till now, they have not been definitely resolved. CONCLUSIONS: Excluding two unresolved cases, sensitivity and specificity of FDG-PET was 100% for malignancy in our series. PET was helpful in medical decision-making in all patients.

Personal dosimetry in the PET Centre Prague.

This work is focused on radiation protection in the PET Centre Prague. The personal year dose equivalents of physicians, technologists and lab-technologists in the period 1997-2000 are presented. Dose equivalents are listed for each group as collective, mean and maximum dose equivalents and number of people in the evaluated group. There is an increase in the dose equivalents in 1999 when the PET scanner was installed. Later on, when personnel was trained and better local shielding was used, the increase is not much higher even though the number of patients investigated per day doubled. The radiation field measurements showed that the radiation dose equivalent rate outside the controlled area is on the background level of about 0.17-0.18 mSv/hour.

Introducing the PET Centre Prague.

The PET Centre Prague (www.homolka.cz/nm) was established in 1999 as the outcome of a joint project of the public Na Homolce Hospital and the Nuclear Research Institute Rez, plc, the Czech radiopharmaceutical producer. Technical and financial assistance was provided by the International Atomic Energy Agency, which perceived the Centre as its model project that could serve as a guide for the development of PET centres in countries sharing a comparable level of development with the Czech Republic. The article maps the history of the project, its design, workplace lay-out and equipment, radiation protection arrangements and spectrum of the first approx. 3,000 investigations.

Attenuation correction stress myocardial SPECT: possibility of reduction in number of rest investigation.

BACKGROUND: Attenuation-corrected (AC) imaging frequently shows normal stress myocardial perfusion while non-corrected (NC) imaging shows hypoperfusion. The aim of the work was to assess whether it is necessary to continue with resting examination in this situation. MATERIAL AND METHODS: 121 consecutive patients had positive finding at AC and/or NC sestamibi stress myocardial imaging using E.CAM Profile system and resting examination was carried out. AC stress imaging was normal while NC imaging showed hypoperfusion in 29 cases. In one case this finding was reversed. In this group of 30 patients with AC/NC stress discrepancies, resting examination has not revealed any additional information in 28 cases. RESULTS: In 2 cases NC imaging, in contrast to AC, showed stress ischaemia. In one of these 2 cases coronarography was carried out with negative result. In the other case patient refused coronarography. CONCLUSIONS: The resting examination did not bring any benefits in 29-30 cases out of 30 (96.7 to 100.0%) patients with AC/NC stress discrepancies. If the results of this study are considered accordingly, in our group approximately one fourth of the resting examinations (29 to 30 out of 121) could be saved.