Comparison of 18F-FDG and 67Ga-citrate in sarcoidosis imaging.

AIM: (67)Ga citrate has been used long and successfully to diagnose and stage sarcoidosis. (18)F-fluorodeoxyglucose ((18)F-FDG) has been suggested as a positron emission tomography (PET) tracer for sarcoidosis imaging. This study aimed to analyze possible advantages of (18)F-FDG-PET over (67)Ga citrate scintigraphy during the primary assessment of patients with sarcoidosis. PATIENTS AND METHODS: Twenty-four patients (11 men, 13 women, aged 52 years +/-12.4) with histologically proven sarcoidosis were investigated with (18)F-FDG and (67)Ga citrate. Equipment included a full-ring PET scanner (ECAT EXACT HR+, Siemens/CTI, Knoxville TN, USA) and a double-headed gamma camera (ECAM, Siemens, Illinois, USA) for scintigraphy. The mean time difference between the two studies was 6.5 days (range: 5-8 days). RESULTS: There was a significant difference in the detection of pulmonary and nonpulmonary sarcoidosis lesions between planar (67)Ga citrate scans and (18)F-FDG-PET images (<0.0021). A total of 64 lesions were detected with (67)Ga citrate scans in the thorax and elsewhere with a mean of 2.6 lesions (4%) per patient, while 85 lesions were found with (18)F-FDG-PET, with a mean of 3.5 lesions (4.1%) per patient. There was complete agreement between (18)F-FDG and (67)Ga citrate in thoracic manifestations in four (16.6%) patients, and in non-thoracic manifestations in five (20.8%) patients. The interobserver variability showed a kappa value of 0.79. CONCLUSION: (67)Ga citrate and (18)F-FDG are useful tracers for diagnostic evaluation of thoracic sarcoidosis. (18)F-FDG seems to be more suitable for imaging the mediastinum, the bi-hilar lymph nodes, the posterior regions of the lungs and non-thoracic lesions. Further prospective studies are needed to clarify the role of both tracers in early diagnosis and staging of sarcoidosis, and to resolve questions concerning medical treatment and follow-up.

Pathology results in [18F]fluorodeoxyglucose positron emission tomography of the thyroid gland.

The aim of this retrospective study was to evaluate pathologically increased uptake of [18F]fluorodeoxyglucose (18F-FDG) in positron emission tomography (PET) results of the thyroid gland. Results of 18F-FDG PET and [99mTc]pertechnetate scintigraphy of the thyroid gland are shown, compared to each other and discussed. In a retrospective study 16 patients underwent whole-body 18F-FDG PET and [99mTc]pertechnetate scintigraphy of the thyroid gland within 3 weeks. In addition, an examination of the thyroid gland by using ultrasound and laboratory tests was carried out. The 18F-FDG PET studies were carried out on a dedicated whole-ring PET scanner. Eight patients had a pathological FDG uptake in the thyroid and a cold nodule in [99mTc]pertechnetate scintigraphy of the thyroid gland (in 7/8 cases histology showed malignancy). Five patients had an inhomogeneous FDG uptake in the thyroid gland and were suspected of thyroiditis in 18F-FDG PET (in 3/5 cases thyroiditis was confirmed). Three patients had an especially low FDG uptake compared to normal physiological FDG uptake (no malignancy). Results from studies using 18F-FDG represent a growing body of evidence showing the differentiation between malignant and benign disease: we saw many pathological results in the thyroid gland. High uptake of 18F-FDG in the thyroid gland suggests possible malignancy. Thyroiditis can only be suspected based upon the results of 18F-FDG PET. We conclude that 18F-FDG PET has a potential clinical impact for detecting possible malignant lesions of the thyroid gland, but further studies, in which a higher number of patients are evaluated, are necessary.

18F-FDG PET: early postoperative period of oro-maxillo-facial flaps.

AIM: We addressed the feasibility of FDG-PET to differentiate between viability and non-viability in the immediate postoperative assessment of flaps (autologous microvascular anastomosed pedicled flaps) in oro-maxillo-facial surgery. METHODS: 3-7 days after surgery, FDG-PET was done in 38 patients who had received flaps for re-construction of the mandible after partial resection. The studies were done on a dedicated full ring PET-scanner (ECAT EXACT HR+, Siemens/CTI). Acquisition started between 60 and 80 min post injection. The findings of the soft tissue component of the flaps were grouped using a three point scale: (I) no defect, (II) small defects, (III) one large defect. The results of PET were compared with the clinical course for at least 3 months. RESULTS: "No defect" on the FDG-PET study identified vi-ability of the flap and predicted normal clinical follow-up (22/38 patients). "Small defects" visualized areas of decreased perfusion and decreased glucose metabolism indicating risk of non-viability (13/38 patients); adapt-ing the postsurgical management led to delayed but uncomplicated healing of the flaps in these patients. "One large defect" demonstrated early necrosis of the flap (3/38 patients). After removal and replacement of this necrotic portion of the flap the second FDG-PET scan of these 3 patients demonstrated the uncomplicated post-operative healing. CONCLUSION: FDG-PET facilitated the assessment of viability and non viability of flaps in the immediate postsurgical period, and demonstrated the usefulness of FDG-PET for postoperative care and prognosis.

Diagnosis of a contralateral second testicular carcinoma by F18-FDG PET.

BACKGROUND: In testicular carcinoma the early diagnosis is very important because with an early therapy there are good chances for long-term survival (50-90%). Metastases of a testicular carcinoma are at first lymphogenous, hematogenous only in late stages. CASE REPORT: This is a case report about a 28-year-old man, whose testicular carcinoma (left testis) had already been operated on (unripe teratoma with parts of an embryonic carcinoma, an endodermal sinus tumor and a chorion carcinoma). Because of the elevated tumor marker AFP an FDG PET (F18-fluorodeoxyglucose positron emission tomography) investigation was made. CT (covering thorax, abdomen and pelvis) and ultrasound of the testis showed no pathological results. In the FDG PET a significant pathological FDG uptake in the right testis was found. Histology showed an unripe teratoma with parts of an embryonic carcinoma, an endodermal sinus tumor, and a chorion carcinoma. It was a second carcinoma of the contralateral testis. CONCLUSION: F18-FDG PET was a sensitive and reliable modality for diagnosis in this patient.

Localization and diagnosis of septic endoprosthesis infection by using 99mTc-HMPAO labelled leucocytes.

The aim of this study was to evaluate, retrospectively, the diagnostic value of Tc hexamethylpropylene amine oxime (99mTc-HMPAO) labelled autologous leucocytes for the preferred septic localizations of the infection of the endoprosthesis. We retrospectively reviewed 67 patients with implanted endoprostheses. Diagnosis was found in 42/67 patients. In 25/67 patients we were able to negate an acute pathological process of infection of the endoprosthesis. Our patients were divided into three groups according to the type of endoprosthesis (hip joint, knee joint, shoulder joint). The localizations of the endoprosthesis disorders are shown. The preferred localizations of the acute infection of the hip endoprosthesis are the regio intertrochanterica and the middle part of the shaft of the prosthesis. The preferred localization of the acute infection of the knee endoprosthesis is the proximal shaft of the tibia. The preferred localization of the acute infection of the shoulder endoprosthesis is the distal end of the prosthesis in the proximal humerus. It is hoped that the knowledge of these preferred localizations of infection of endoprosthesis will help patients and doctors in diagnosis and treatment in the future.

[Diagnosis of metastasis of malignant melanoma in the thyroid gland with f18-FDG PET scan]. / Diagnostik einer Metastase eines malignen Melanoms in der Schilddrüse mittels F18-FDG-PET.

Metastases in the thyroid gland are very rare. When they occur, long-term survival is dismal; thus an early diagnosis is critical. Malignant melanoma is one of the tumors which may metastasize to the thyroid gland. Therefore we wanted to demonstrate F18-Fluorodeoxyglucose-Positron emission tomography (F18-FDG-PET) is a sensitive and reliable method to identify such metastases. We report about a 51-year-old man, who had an inguinal lymph node metastasis of a malignant melanoma with unknown primary tumor site. He came to us for an a follow-up F18-FDG-PET investigation. In the PET there was a pathologic FDG-uptake in the left lobe of the thyroid gland. The nodule was removed and showed a malignant melanoma metastasis. This unusual scenario underscores the value of the PET in the oncologic follow-up of patients with malignant melanoma.

Diagnosis of bone infection using 99m Tc-HMPAO labelled leukocytes.

In order to evaluate the importance of 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO) leukocyte scintigraphy in the diagnosis of bone infection, we retrospectively reviewed 324 patients. Abnormal findings were seen in 221 patients. In the other 103 cases acute pathological inflammation could be ruled out. The patients with pathological findings were divided into four groups according to the location of the infection. This method showed the localizations of skeletal disorders and its differences to other diagnostic imaging modalities. The underlying abnormalities causing the inflammation were determined. In conclusion, 99mTc-HMPAO leukocyte scintigraphy is still a very sensitive method for either whole body screening or local detection of acute or exacerbated chronic osteomyelitis. The advantages of this method over other diagnostic imaging methods are shown.

Digital image fusion of CT and PET data sets--clinical value in abdominal/pelvic malignancies.

PURPOSE: We investigated the clinical relevance of digital image fusion of CT and 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) positron emission tomography (PET) studies in patients with suspected abdominal and/or pelvic metastasis. METHOD: Nineteen patients with suspected residual/recurrent malignancies underwent CT and [18F]FDG PET studies of the abdomen and/or pelvis. The data sets of both modalities were fused on a digital workstation by automatic adaptation of the pixel size and the slice thickness. Different body positions were corrected by semiautomatic adaptation of the body axes. The fused images were reconstructed in sagittal, coronal, and axial planes. RESULTS: Good spatial correlation between both modalities was achieved in all patients. Image fusion improved the spatial allocation of pathologically increased [18F]FDG uptake in 7 of 35 lesions (20%). CONCLUSION: This work suggests that digital image fusion of CT and [18F]FDG PET data sets improves the anatomical localization of foci with increased [18F]FDG enhancement of the retroperitoneum and the abdominal/pelvic wall, respectively.

Renography before heart transplantation in patients with cardiomyopathy.

UNLABELLED: In patients with ischemic cardiomyopathy (CM), abnormal renograms may result not only from circulatory failure (which should reverse after transplantation) but also from intrinsic renal disease (which contraindicates heart transplantation). Here, the outcome of heart transplantation was related to preoperative renograms, and the differentiating and prognostic value of renography was analyzed. METHODS: The study population consisted of 50 patients with ischemic CM expecting heart transplantation. Anatomical renal pathology was excluded in all patients. Dynamic renal scintigraphy was performed with 99mTc-mercaptoacetyltriglycine. Background-subtracted renograms were inspected visually and characterized numerically. Mean parenchymal transit time (mPTT), renal tracer content at 15 min (RTC15) and retention index (RI) were determined. The parametric renogram values were related to a normal reference group of 64 patients. The preoperative renograms were matched with the postoperative outcome. RESULTS: Three characteristic types of symmetrical findings in the kidneys were found: no pathological findings, mildly delayed peak and excretion phase and severely delayed peak and excretion phase. Pathological renograms were observed in 36 of 50 (72%) patients. The mean parametric renogram values in ischemic CM were as follows: Group A (normal kidney function), mPTT = 142+/-26.6 sec, RTC15 = 22.3%+/-4.6% and RI = 24.7+/-11.9; Group B (mild dysfunction), mPTT = 210+/-44.0 sec, RTC15 = 42.6%+/-10.3% and RI = 101.4+/-50.5; Group C (severe dysfunction), mPTT = 320+/-94.2 sec, RTC15 = 79.6%+/-15.9% and RI = 347.7+/-194.7; and reference patients (normal kidney function), mPTT = 137+/-31.1 sec, RTC15 = 22.8%+/-3.8% and RI = 24.6+/-7.9. Postoperative serum creatinine levels were <1.5 mg/dl in all Group A patients, between 1.5 and 2.5 mg/dl in 78% of Group B patients and >2.5 mg/dl in 75% of Group C patients. CONCLUSION: Renography revealed abnormal kidney function when structural pathology was excluded. The renographic abnormalities in ischemic CM did not reflect simply the circulatory failure. The numerical grading of renograms allowed patient stratification, suggestive of possible renal insufficiency after cardiac transplantation and immunosuppressive therapy. With further experience, renography may become a useful tool for predicting postoperative outcome in ischemic CM.

Technetium-99m-ECD SPECT fails to show focal hyperemia of acute herpes encephalitis.

This is a case of herpes simplex encephalitis (HSE) examined with 99mTc-ethyl cysteinate dimer (ECD) and 99mTc-hexamethyl propyleneamine oxime (HMPAO) SPECT. Static images obtained with 99mTc-ECD showed a reduced tracer uptake of the temporal lobe but focal hyperactivity using 99mTc-HMPAO. Dynamic images indicated regional increase of cerebral blood perfusion with both tracers. Technetium-99m-ECD had rapid washout from the inflamed tissue, while 99mTc-HMPAO had avid uptake. Hypofixation of 99mTc-ECD leads to failure to detect the characteristic finding of temporal lobe hyperemia in acute HSE.

Neopterin concentrations in cerebrospinal fluid and serum as an aid in differentiating central nervous system and peripheral infections in children.

Neopterin is a sensitive indicator for cellular immune activation. Its concentrations were determined in cerebrospinal fluid (CSF) and serum specimens from 91 children with no evidence of central nervous system (CNS) or peripheral inflammations, 43 with definite neuroborreliosis, 51 with other CNS infections, and 33 with peripheral infections. The aim of our study was (a) to establish a range of normal CSF neopterin concentrations in control children, and (b) to inquire into the diagnostic potential of neopterin measurements in both body compartments for aiding in differential diagnosis of inflammatory vs noninflammatory diseases, and CNS vs peripheral inflammations. CSF neopterin concentrations in controls were invariably low (up to 9.3 nmol/L), but in children with neuroborreliosis and, even more so, with other CNS infections neopterin concentrations were significantly (P <0.0001) increased. Children with peripheral infections, however, rarely showed raised CSF neopterin concentrations. Serum concentrations of neopterin, on the other hand, were not significantly different between controls and children with neuroborreliosis. Although serum concentrations were significantly different between controls and children with other CNS infections, diagnostic efficiency was poor for this comparison. Peripheral infections, in contrast, were associated with significantly higher (P <0.0001) serum neopterin concentrations when compared with controls. A classification tree was constructed on the basis of CSF and serum neopterin concentrations, allowing with high accuracy the discrimination between controls, children with CNS infections, and children with peripheral infections. Thus, on the basis of a comparatively large control group, our data underline the diagnostic validity of neopterin as an aid in differential diagnosis of inflammatory vs noninflammatory diseases, and confirm that CSF neopterin concentrations are not correlated with serum neopterin concentrations, and, therefore, CSF neopterin appears to be produced intrathecally.

A case of parathyroid carcinoma visualized on Tc-99m-sestamibi scintigraphy.

Recent studies indicate that Tc-99m-Sestamibi (MIBI, DuPont Pharma) is a useful tracer for detecting parathyroid adenomas. We present a patient with focal Tc-99m-MIBI uptake in parathyroid carcinoma which has only been described once before (1). Tc-99m-MIBI scintigraphy may be considered for diagnosing pathological parathyroid tissue. But presently the histopathological examination only allows the differentiation between adenoma and carcinoma.

First experiences with technetium-99m furifosmin as tumour-seeking agent in breast cancer and recurrent ovarian cancer.

Recent in vitro studies suggest that technetium-99m furifosmin may have tumour-seeking properties. We analysed the diagnostic value of 99mTc-furifosmin scintigraphy in nine patients with documented carcinoma of the breast and in eight patients with continued recurrent ovarian cancer. In the breast, 99mTc-furifosmin failed to visualize the primary malignant tumour and the associated malignant lymph nodes in all patients. In contrast, multiple sites of increased tracer uptake were demonstrated in one patient with acute benign inflammatory breast disease. In four of eight patients with recurrent ovarian cancer, 99mTc-furifosmin scintigraphy demonstrated early (5 min p.i.) localized increased uptake corresponding to adhesions to the bowel as diagnosed by computed tomography, but failed to reveal further abnormalities in all patients. The present study demonstrates that furifosmin is of no value in the imaging of breast cancer and recurrent ovarian cancer. These results do not continue the pattern observed in cell culture studies and are quite in contrast to the findings of mammoscintigraphy using 99mTc-methoxyisobutylisonitrile and 99mTc-tetrofosmin.

99Tcm-tetrofosmin scintigraphy in Hodgkin's disease.

The aim of this study was to assess the suitability of 99Tcm-tetrofosmin (tetrofosmin) scintigraphy as a diagnostic modality in patients with Hodgkin's disease. Fourteen untreated patients with biopsy proven Hodgkin's disease (clinical stage Ia-IVb) were investigated. Post-treatment investigations were also done in 7 of the 14 patients. Focal pathological tetrofosmin uptake was seen in 42 site in the pre-treatment studies. Computed tomography identified 36 pathological regions. The tumour-to-background ratio ranged from 1.44 to 2.17 (mean 1.63). Follow-up studies demonstrated a response to treatment, in that there was a reduction in, or complete disappearance of, localized tetrofosmin uptake in regions previously pathological, and a decrease in tumour-to-background ratios. Tetrofosmin appears suitable for the localization of lymphomatous lesions, especially supradiaphragmatic ones, and for the follow-up of therapeutic response.

Parathyroid scintigraphy: first experiences with technetium (III)-99m-Q12.

We report the preliminary results of a prospective study demonstrating technetium(III)-99m furifosmin (Q12) uptake in histologically proven parathyroid adenomas. Scintigraphy was performed in 12 patients with hyperparathyroidism. Q12 correctly identified the parathyroid adenomas by focal prolonged tracer retention in ten of the 12 patients. In the two patients without localized tracer retention, no parathyroid adenoma could be identified surgically, either. The retention half-times ranged from 0.5 to 1.8 h (mean 1.27) in the parathyroid adenomas and from 0.3 to 1.2 h (mean 1.05) in the thyroid gland. Our preliminary results show that Q12 is a feasible, sensitive tracer for parathyroid scintigraphy. In comparison to sestamibi (MIBI) and tetrofosmin, Q12 displays short retention in the thyroid gland, which would seem rather advantageous. Further evaluation is needed to determine which among Q12, tetrofosmin and MIBI is most sensitive for the detection especially of small parathyroid adenomas, and which tracer properties will best reflect the degree of endocrine activity.

Cholescintigraphy in the evaluation of bile flow after Roux-en-Y hepatico-jejunostomy and hepatico-antrostomy in infants with choledochal cysts.

BACKGROUND: The study tests the hypothesis that stasis of bile in the Roux-en-Y hepatico-jejunostomy (RYJS) loop might facilitate biliary reflux and cause cholangitis, whereas quicker transit times in hepatico-antrostomy (HAST) might prevent cholangitis. MATERIALS AND METHODS: Cholescintigraphy was performed using Tc99m-trimethyl-Br-IDA in seven RYJS patients and in five HAST patients. RESULTS: The time to peak (Tmax) within the RYJS loop occurred between 18 and 50 min postinjection in all patients and the mean transit time (MTT) ranged between 42 and 69 min in 5/7 patients. Prolonged clearance of the tracer from the liver was seen in 2/7 RYJS patients, in whom the MTT was 77 and 240 min, respectively. In the HAST group, the Tmax within the anastomosed antrum occurred between 5 and 33 min postinjection, and the MTT ranged between 42 and 44 min in 2/5 patients. Protracted tracer uptake in the liver in one patient and localised tracer retention in the left hepatic bile ducts in 2/5 patients caused prolonged MTTs. Recurrent cholangitis and diarrhoea occurred in 4/7 RYJS patients, but in none of the HAST patients. Elevated gastrin levels after RYJS contrasted sharply to normal gastrin levels after HAST. CONCLUSION: The findings on cholescintigraphy did not differ significantly between RYJS and HAST and provided no explanation for the distinctly different postoperative clinical course of both surgical methods. Nevertheless, we consider cholescintigraphy to be an efficient and cost-effective diagnostic modality for evaluation of the surgical outcome as regards biliary flow.

Semi-quantitative scintigraphic follow-up studies of cerebral arteriovenous malformations after radiosurgical treatment.

An evaluation of semi-quantitative 99Tcm-red blood cell scintigraphy (RBCS) was undertaken in patients with cerebral arteriovenous malformations (AVM) during follow-up after radiosurgical treatment. Twenty-seven patients were studied with an initial dynamic imaging sequence of 32 frames each lasting 2 s, planar images in four projections beginning 15 min post-injection and single photon emission tomography immediately following the planar imaging. A 2 ml cubital vein blood sample was imaged to obtain an extracorporeal equivalent of the intravascular activity. The counts within the AVM on a planar image were divided by the counts obtained from the image of the blood sample (corrected for the same acquisition time and radioactive decay). This value yielded the 'volume index' (VI), which was proportional to the volume of the AVM. The VI obtained from the first RBCS served as the initial reference value and was set at 100%. The VIs obtained from the follow-up investigations of the same patient in the same projection were expressed as the percentage of the initial VI. We found RBCS identified the AVM in all patients. The VIs obtained from the follow-up studies demonstrated a decrease in blood volume at different time intervals after radiosurgical treatment. RBCS provides a sensitive, relatively non-invasive, semi-quantitative method for measuring the relative volume and follow-up of the degree of obliteration of AVMs after radiosurgical treatment.

Follow-up of osteomyelitis of infants with systemic serum parameters and bone scintigraphy.

AIM: To prevent orthopedic sequelae in acute hematogenous pyogenic osteomyelitis (AHPO) of infants early diagnosis, recognition of recurrence and effective therapy is needed. This retrospective study of 47 infants with bacteriologically confirmed AHPO concerned with an analysis of the diagnostic value of systemic serum parameters compared to bone scintigraphy (BSC). METHODS: AHPO was characterized initially and during the course of disease by clinical findings, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), total and differential white blood cell (WBC) count, BSC, and plain radiography. RESULTS: CRP was the most effective serum parameter for follow-up of disease. The first sign of BSC to signal adequate response to antibiotic treatment was the decrease or normalization of hyperperfusion. Escape from therapy or poor prognosis, even when the serum parameters were normalized, was signaled by the recurrence of focal hyperperfusion and the persistent or increasing local uptake ratios on the 3-h-image over 6 weeks during a course of antibiotic treatment. CONCLUSION: Antibiotic treatment masks the clinical presentation, and the radiographic findings, causes non-characteristic laboratory findings, but do not prevent the scintigraphic visualization; BSC and serum parameters used in the right completion are the most successful and efficient modalities for follow-up of AHPO. Maintenance of antibiotic therapy should be done until BSC findings have reverted to normal.