Stability and pharmacokinetics of m-[131I]iodobenzylguanidine in patients.

A pharmacokinetic study was done to elucidate the body distribution, elimination, and metabolism of m-[131I]iodobenzylguanidine (m-[131I]IBG). For this purpose, an analytical method using solid phase extraction columns was developed. m-[131I]IBG was administered as an i.v. infusion according to different schedules with doses of 7,055 to 13,580 MBq/m2. At the start of the infusion m-[131I]IBG accounted for 93.0 +/- 2.3% (SD; n = 10) of the total radioactivity. At the end of the infusion m-[131I]IBG accounted for 88.0 +/- 7.4%. The non-m-IBG-bound radioactivity was predominantly 131I. The pharmacokinetic parameters (n = 7) are adequately described by a three compartment model. The parameters for m-[131I]IBG were determined with a mean terminal half-life of 37.0 h, a volume of distribution of 307 liters/m2, and an area under the curve value of 1091 kBq x h/ml. The total body clearance was 189 ml/min/m2. The values for 131I showed a terminal half-life of 71.6 h, a volume of distribution of 190 liters/m2, and an area under the curve value of 1537 kBq x h/ml. The total body clearance was 70 ml/min/m2. The selectivity of the m-[131I]IBG treatment might be improved by a reduction of 131I in the infusion fluid and further investigations are warranted.

Catecholamine secreting glomus tumor detected by iodine-123-MIBG scintigraphy.

We report the case of a 41-yr-old woman who presented with arterial hypertension and tinnitus in the right ear synchronous with pulse. She had previously undergone surgery for suspected pheochromocytoma without positive therapeutic effect. CT and MRI revealed a homogenous tumor with contrast enhancement in the right hypotympanon and foramen jugulare, and [123I]metaiodobenzylguanidine (MIBG) scintigraphy demonstrated strong tracer uptake in the same area. Selective venous sampling of catecholamines in the ipsilateral jugular vein confirmed the tumor to have originated from hormone production.

Fluorine-18-FDG and iodine-131-iodide uptake in thyroid cancer.

UNLABELLED: We conducted a prospective study to define the sensitivity of 131I scintigraphy and 18FDG PET whole-body scanning in the detection of thyroid cancer and metastases. METHODS: Forty-one patients with differentiated thyroid carcinoma who underwent thyroidectomy and 131I elimination of the remaining thyroid were studied by 18FDG whole-body PET in 52 examinations and by 131I whole-body scanning. RESULTS: Combined 18FDG and 131I imaging resulted in a sensitivity of about 95%, with alternating uptake of 131I and 18FDG in the metastases: 131I trapping metastases with no 18FDG uptake and 18FDG trapping metastases with no 131I uptake. Five uptake types were differentiated. Alternating uptake was found in about 90% of the patients, which was nearly identical to the sensitivity of the combined 131I/18FDG investigation. In six patients with increasing human thyroglobulin levels, we found that 18FDG whole-body PET localized positive neck metastases of papillary thyroid carcinomas that were histologically confirmed after extirpation. CONCLUSION: Combination 18FDG and 131I whole-body imaging protocol enables detection of local recurrence or metastases on whole-body scans that are often not shown by other imaging methods. Biochemical grading of thyroid cancer may also be possible with this method: Tumors with remaining functional differentiation for hormone synthesis and iodine uptake have low glucose metabolism in more than 95%; tumors without this functional differentiation of 131I uptake show high, glucose metabolism. Fluorine-18-FDG uptake seems to be an indicator of poor functional differentiation, and possibly higher malignancy, in thyroid cancer.

Detection of infection in postoperative orthopedic patients with technetium-99m-labeled monoclonal antibodies against granulocytes.

A prospective study of 106 orthopedic patients was performed for the detection of infection in the early postoperative stage using 99mTc-labeled murine Mabs directed against epitopes on granulocytes. Accuracy was 81% in the hips (n = 26), 81% in the thigh (n = 21), 84% in the knee (n = 19), and 100% in the tibia (n = 27). The technique did not work well in the spine where false-negative results were observed in the three patients studied. One patient suffered transient swelling of the eyelids following injection. Optimal imaging results were obtained 2-6 hr postinjection.

Incidental finding of a hepatic lesion: differential diagnostic problems for fibrolamellar hepatic carcinoma.

We report the case of a 39-yr-old female with a liver lesion that was incidentally detected by ultrasound. Examination of biopsy specimens revealed focal nodular hyperplasia. A metastatic tumor in the right os ilium developed in the following weeks and showed specific uptake of 99mTc-hepatic 2,6-dimethyliminodiacetic acid (HIDA), suggesting metastasis from a differentiated hepatocellular carcinoma. The final pathologic diagnosis was multifocal, solid and glandular hepatocellular carcinoma, partly differentiated as fibrolamellar carcinoma, and an osseous metastasis from the differentiated hepatocellular carcinoma.

[131I]-metaiodobenzylguanidine in the treatment of metastatic neuroblastoma. Clinical, pharmacological and dosimetric aspects.

Ten children with stage III or IV neuroblastoma that had either relapsed or was refractory were treated with [131I]-metaiodobenzylguanidine (MIBG) from 1984 to 1986. The total dose ranged from 4,365 to 21,900 MBq and was given in one to five courses. Two patients achieved a complete remission (CR), two, a partial remission (PR), and three, an arrest of the disease. Pharmacological studies showed that 93% of detectable radioactivity was attributable to MIBG at the beginning of the infusion. However, by the end of the infusion this had decreased to 88%. The terminal half-life of MIBG was 37.0 h, whereas that of non-MIBG-bound iodine was 71.6 h. Therefore, the radioactivity-time product of non-MIBG-bound 131I was much higher than that of MIBG. Dosimetric studies showed a mean level of absorbed radiation for the total body of 160 microGy/MBq, a liver irradiation of 540 microGy/MBq and a mean tumour radiation of 10,500 microGy/MBq.

Positron emission tomography and ultrasonography. A comparative retrospective study assessing the diagnostic validity in lymph node metastases of malignant melanoma.

BACKGROUND AND DESIGN: A retrospective study involving 20 patients with melanoma with clinically suspicious lymph nodes was conducted to compare the diagnostic validity of fludeoxyglucose F 18 positron emission tomography (PET) and real-time ultrasonography in lymph node metastases of malignant melanoma. RESULTS: A total of 83 lymph nodes were assessed with ultrasonography and PET. Imaging results were confirmed by histologic studies or close follow-up ultrasonographic examinations. Positron emission tomography revealed a sensitivity of 74% and a specificity of 93%. Both investigative methods show comparative sensitivity and specificity. CONCLUSIONS: Ultrasonography is much easier to perform, less time-consuming, and less expensive than PET and it is nonhazardous; therefore, it is ideal for follow-up procedures. Since in routine staging procedures, only sites of expected lymph node involvement are examined, there is a risk of metastases being missed in cases of atypical drainage patterns. Fludeoxyglucose F 18 PET can image proliferating tumors in multiple organ systems and lymph node sites in one session, making it suitable for screening in primary staging procedures and for monitoring response to therapy. Since it is based on metabolic changes, there is good differentiation between scar and tumor tissue. Major disadvantages are restricted access to investigation centers, high imaging costs, and limited anatomical location of metastatic lesions. We conclude that PET does not offer significant advantages in the diagnosis of lymph node metastases compared with ultrasonography.

Primary choriocarcinoma of the pulmonary artery mimicking pulmonary embolism.

Due to their rarity, primary tumours of the pulmonary arteries are often incorrectly diagnosed as more common diseases such as pulmonary thromboembolism and are seldom diagnosed during a patient's lifetime. Surgery or potentially curative chemotherapy may therefore be withheld. We report a patient with a primary choriocarcinoma of the left pulmonary artery, which was first suspected on a CT scan. The neoplastic nature of the obstruction of the pulmonary arteries was confirmed by positron emission tomography.

[Importance of emission computed tomography in chronic disorders of the knee joint]. / Bedeutung der Emissionscomputertomographie bei chronischen Kniegelenksbeschwerden.

Twenty-eight patients with chronic abnormalities of the knee were examined by 3-phase scintigraphy and ECT. The unobscured images produced by ECT provide additional information for evaluating the localisation, extent and activity of the lesions. The diagnosis of meniscus abnormalities in particular revealed pathognomonic patterns. The indications and value of ECT was compared with other diagnostic measures and particularly with invasive techniques (arthroscopy and arthrotomy).

[Tl-201-imaging as a follow-up method after left ventricular aneurysmectomy (author's transl)]. / Verlaufskontrolle nach linksventrikulärer Aneurysmektomie durch 201Thallium-Myokardszintigraphie.

Thallium myocardial scanning was performed in 30 patients after aneurysm resection of left ventricle. The aim of the study was to try an assertion about the completeness of adaptation of the marginal zones of aneurysm and about the postoperative reduction of left ventricular size. After standardization of size and distance of pictures we suggested quantification of dimensions of left ventricle by counting picture-points using a computer matrix. For that purpose left ventricle had to be deliminated exceptional distinctly from the background. That intention was realized by an interpolating background subtraction. Postoperatively an evident reduction of heart size, especially of ventricle cavity could be proved. Thallium myocardial scanning therefore seems to be suitable for postoperative supervision after aneurysm resection too.

[Clinical importance of emission-computed tomography of the skull in bone scintigraphy]. / Klinische Bedeutung der Schädel-Emissionscomputertomographie in der Knochenszintigraphie.

Sixty-five ECT examinations were carried out in patients with abnormalities of the skull base and paranasal sinuses and the results were compared with ordinary scintigraphy and CT. ECT provides additional information as compared with scintigraphy by its images in three planes, which are free of superimposition. This is of value in the localisation of the lesion and for determining its extent and activity. It is a functional tomographic method which is complementary to the morphological information provided by CT. The indications and value of the method in inflammatory, metastatic and neoplastic diseases are discussed.

[Angiodynography of circumscribed thyroid changes]. / Angiodynographie bei umschriebenen Schilddrüsen-veränderungen.

Conventional methods of thyroid diagnosis, such as scintigraphy, differentiate between hot and cold areas, but within cold areas no distinction between malignant and benign changes is possible. Angiodynography provides a new method which gives the usual sonographic information and also indicated variations in blood-flow in the organ. Various diagnostic methods--thyroid scintigraphy, conventional sonography, fine-needle biopsy and angiodynography--have been compared in patients with focal thyroid disease. It has been shown that it is possible to differentiate between malignant and benign lesions on the basis of their vascularisation.

[The scintigraphic diagnosis and follow-up of injuries to the epiphyseal plates (author's transl)]. / Szintigraphische Diagnostik und Verlaufskontrolle bei Epiphysenfugenverletzungen.

Injuries to the epiphysel plates without involvement of the epiphyses or metaphyses, such as crush fractures or pure epiphysiolysis may be difficult to diagnose radiologically. Thirteen bone scans after damage to the growth plate have been performed on eight children. These indicate that these scans are able to diagnose lesions of the epiphyseal plates at an early stage and with certainty. The scintigrams also provide information concerning the healing process of the plate; they indicate when healing has been completed and when the extremity can be used for weight-bearing again. Radiation exposure of the children during scintigraphy with 99mTc-polyphosphate is within acceptable limits.

[First clinical experience with axial emission computer tomography (author's transl)]. / Erste klinische Erfahrungen mit einem axialen Emissions-Computer-Tomographen.

104 examinations were carried out on 81 patients with a new commercial emission computer tomographic scanner. The technique provides additional information in half the brain scans, but only in one third of liver scans. No indications for this examination could be discovered in a relatively small clinical material for the examination of the kidneys or the skeleton. Other organs were not included in this assessment. The authors confirm reports in the literature which show that this method is not particularly valuable for finding pathology. It finds its application in conforming or excluding suspected abnormalities and for better localisation and delineation of lesions, thereby aiding differential diagnosis. However, further technical improvements and increased clinical experiency may increase the applicability of the technique.

[The normal thyroid gland in the scintigram: size and form variants, thyroid dystopia]. / Die normale Schilddrüse im Szintigramm: Grösse und Formvarianten, Schilddrüsendystopien.

Quantitative data about the size of the normal thyroid gland are presented: height, width and area of the right and left lobe are scintigraphically different. The calculated weight varies depending on the correction factor. Displaced thyroid tissue is found in the center line, whereas iodine accumulating tissue located in the lateral neck should lead to a suspicion of carcinoma.

[Follow-up evaluation of metastatic neuroblastoma using high dose [131I-meta]iodobenzylguanidine]. / Verlaufsbeurteilung des metastasierten Neuroblastoms mittels hochdosiertem [131J-meta]Jodobenzylguanidin.

Between 1989 and 1990 nine children with neuroblastoma stage IV (according to Evans) have been treated with high-dose [131I-meta]Iodobenzylguanidine (HD-mIBG). The total HD-mIBG dose administered to each child was at mean 699.3 +/- 111 MBq/kg body weight. Prior to (median 28 days) and after (median 50 days) HD-mIBG treatment a diagnostic scan with [123I-meta]Iodobenzylguanidine ([123I-m]IBG) was performed. Scans performed with HD-mIBG were superior to diagnostic scans for the detection of bone lesions in 8/9 children, for the detection of soft tissue lesions in 4/9 children, and for a more precise diagnosis of the primary tumor in 1 child. In 4 children lesions which were primarily identified in the therapeutic scan could be further observed in posttherapeutical examinations.

[Computer-assisted 201Tl myocardial scintigraphy in the routine diagnosis of coronary heart disease (author's transl)]. / Rechnerunterstützte 201Tl-Myokardszintigraphie in der Routinediagnostik der koronaren Herzerkrankung.

The aim of the study was to evaluate the validity of 201Tl scanning for clinical routine use in the diagnosis of coronary heart disease. A computer-aided matrix with very high resolution displaying subtle color nuances was used. For semi-quantitative assessment a scale with 16 colors was applied. This permitted to differentiate between changes of intensity of 6.25%. Compared with the ECG on exercise no higher sensitivity or specifity of 201Tl scanning was found using coronary angiography as the reference method. When a typical angina pectoris and a pathological ECG on exercise was present, confirmation of the diagnosis of coronary heart disease by scanning was readily obtained. Moreover, in the event of equivocal findings in the ECG and of atypical chest pain scanning is helpful without having to resort to invasive methods. Additionally to the exercise ECG, the location of ischemic areas in the myocardium can be easily demonstrated by scanning. When angiography has shown unobstructed coronary arteries but the ECG is suggestive of scar formation, scintigraphy provides additional information regarding the diagnosis of coronary heart disease. It is also possible by scanning to delineate the tissue defect representing fibrotic areas. This is necessary for instance when aneurysmectomy is planned.

[99mTc-HMPAO leukocyte scintigraphy in the diagnosis of inflammations of the skeletal system. Initial experiences]. / Die 99mTc-HMPAO Leukozytenszintigraphie in der Entzündungsdiagnostik am Skelettsystem. Erste Erfahrungen.

Subsequent to orthopedic surgery 23 patients were studied by leukocyte scintiscanning using 99mTc-HMPAO to detect inflammation. 12 patients had all signs of bacterial infection. In 11 patients infection of the wound area was suspected. There was one false negative and no false positive scintigraphic finding. 2 patients with an unclear postoperative course after internal fracture fixation showed intensive uptake. Several days after the scan both patients developed severe bacterial infection. From that experience we conclude that the method may be of higher sensitivity than clinical symptoms. Further investigations are necessary for an accurate assessment of the method.

Differential diagnosis of metastases in bone scans: chemotherapy induced bone necrosis.

AIM: Influenced by the incorrect diagnosis of a bone metastasis caused by bone necrosis we evaluated reasons and frequency of bone necrosis in patients referred for bone scanning in follow-up of tumors. METHODS: Bone scans performed within two years on patients with primary bone tumors or tumors metastatic to bone were reviewed in respect to the final diagnosis bone necrosis. RESULTS: We found the cases of three young patients who presented the appearance of hot spots on bone scintigrams which were finally diagnosed as bone necrosis. In two cases the diagnosis was based on histological findings, in one case the diagnosis was made evident by follow-up. All the three patients had been treated by chemotherapy and presented no other reason for the development of bone necrosis. Enhanced tracer uptake in all sites decreased within eight weeks up to two years without therapy. CONCLUSION: Single and multiple hot spots after chemotherapy may be originated by bone necrosis but mimicry metastases.

[Comparative diagnosis of focal liver changes using computed tomographic and scintigraphic methods]. / Vergleichende Diagnostik fokaler Leberveränderungen mittels Computer-Tomographie und szintigraphischer Methoden.

The value of scintigraphic methods for the diagnosis of focal lesions of the liver (IDA, colloids, blood pool) in comparison to dynamic sequential computer tomography (CT) has been examined in this study. We found CT to be diagnostic in typical cases. For example, focal nodular hyperplasia is characterized by a rapid, strong increase and subsequent decrease after application of contrast medium (71%), whereas hemangiomas show a delayed density increase mostly at the rim (20%). In the event of deviations from the typical pattern, scintigraphic methods have to be applied which then often yield a specific diagnosis, especially in hemangiomas, focal nodular hyperplasia, and adenomas (71%). Ultrasound findings indicating the possible presence of hemangiomas or focal nodular hyperplasia should lead to scintigraphic studies prior to CT, not only for reasons of economy.