Septale Myokardperfusion bei komplettem Linksschenkelblock: Kasuistik und Literaturübersicht

Bei einer 55jährigen Frau mit komplettem Linksschenkelblock (LSB) wurden bei koronarangiographisch ausgeschlossener RIVA-Stenose innerhalb eines Jahres drei Myokardszintigraphien durchgeführt. Die erste Szintigraphie mit Tc-99m-Sestamibi zeigte einen anteroseptalen Defekt nach Fahrradergometrie. Dieser Defekt konnte in den beiden folgenden Szintigraphien nach pharmakologischer Belastung mit Dipyridamol weder mit TI-201 noch mit Tc-99m-Sestamibi reproduziert werden. Die Ruheuntersuchung erfolgte in allen Fällen mit TI-201 und war normal. Schlußfolgernd ist bei LSB der pharmakologischen Belastung mit Dipyridamol der Vorzug vor der Ergometrie zu geben; die Wahl des Radiopharmakons spielt demgegenüber für die diagnostische Genauigkeit der Myokardszintigraphie eine untergeordnete Rolle.

Assessment of Myocardial Viability in Persistent Defects on Thallium-201 SPECT after Reinjection Using Gradient-Echo MRI

This prospective study assessed myocardial viability in 30 patients with coronary heart disease and persistent defects despite reinjection on TI-201 single-photon computed tomography (SPECT). In each patient, three observers graded TI-201 uptake in 7 left ventricular wall segments. Gradient-echo magnetic resonance imaging in the region of the persistent defect generated 12 to 16 short axis views representing a cardiac cycle. A total of 120 segments were analyzed. Mean end-diastolic wall thickness and systolic wall thickening (± SD) was 11.5 ± 2.7 mm and 5.8 ± 3.9 mm in 48 segments with normal TI-201 uptake, 10.1 ± 3.4 mm and 3.7 ± 3.1 mm in 31 with reversible lesions, 11.3 ± 2.8 mm and 3.3 ± 1.9 mm in 10 with mild persistent defects, 9.2 ± 2.9 mm and 3.2 ±2.2 mm in 15 with moderate persistent defects, 5.8 ± 1.7 mm and 1.3 ± 1.4 mm in 16 with severe persistent defects, respectively. Significant differences in mean end-diastolic wall thickness (p <0.0005) and systolic wall thickening (p <0.005) were found only between segments with severe persistent defects and all other groups, but not among the other groups. On follow-up in 11 patients after revascularization, 6 segments with mild-to-moderate persistent defects showed improvement in mean systolic wall thickening that was not seen in 6 other segments with severe persistent defects. These data indicate that most myocardial segments with mild and moderate persistent TI-201 defects after reinjection still contain viable tissue. Segments with severe persistent defects, however, represent predominantly nonviable myocardium without contractile function.

Classification of the Lymphatic Drainage Status of a Primary Tumour: a Proposal

Aim: Creation of a classification of the lymphatic drainage status of a primary tumour. It shall enable comparison of different approaches, standardisation and quality control. Methods: Identification and topographic localisation of the sentinel node(s) using lymphatic radionuclide gamma camera imaging and/or gamma probe detection and/or vital dye mapping. Results: A classification comprising four classes (D-Class I-IV) and distinct subclasses (A–E) proved to be simply to be learned and applicable as well as reliably reproducible. It is based on the number of sentinel lymph nodes and their locations and can be combined with the pathological and molecular biological lymph node status. D-classes/subclasses obtained in 420 patients with malignant melanoma of the skin are presented. Conclusions: The classification is applicable to different approaches. Its diagnostic, therapeutic and prognostic value should be studied prospectively in those primary tumours which preferably metastasise via their draining lymphatic vessels.

New Aspects of Cellular Thallium Uptake. Tl+-Na+-2Cl–-Cotransport Is the Central Mechanism of Ion Uptake

Cellular uptake mechanisms of 201T1+ were studied in Ehrlich mouse ascites tumor cells. 201Tl+ passes the cell membrane of tumor cells using three transport systems: the ATPase, the Tl+-Na+-2Cl−-cotransport, and the Ca++-dependent ion channel. In the case of 201T1+ the main route for entering the cells was the cotransport, its importance increasing with the age of the cells; in parallel, the ATPase activity was reduced. In contrast, the transport capacities of the ATPase and the cotransport were of the same magnitude in the case of 42K+ and 86Rb+. This change in ion distribution was not brought about by varying velocity relations but by changing the number of transport systems in the cell membrane. There was no relationship between transport rates and diameters of the ions. 201T1+ distribution is proportional to that of K+ with a higher intracellular concentration of about 30%. Under physiological conditions the cotransport was reversible suggesting the ability to regulate steady state during varying extracellular ion concentrations. Cells and medium were two compartments, kinetically seen. Due to the significant difference of transport capacities between the three systems with the respective ions the term “potassium-thallium-analogy” may be misleading as it erroneously assumes identical uptake conditions.

Scintigraphic results in patients with lung transplants

Aim: We addressed the feasibility of scintigraphy in the postoperative monitoring of lung transplants. Method: 37 patients (22 women, 15 men, 37 ± 15 years) in good clinical condition were examined after lung transplantation. Scintigraphic procedures for assessing ventilation (133Xe), perfusion (99mTc micro-spheres) and aerosol-inhalation (99mTc aerosol) were performed for all patients. The findings were compared with those of established diagnostic modalities. Results: All lung transplants showed homogeneous ventilation but with a non-physiologic difference of over 20% between both pulmonary lobes in one-third of the cases. There was a difference between the impairement of perfusion and ventilation in the presence of an impaired Euler-Liljestrand reflex in 14/37 (38%) patients. Furthermore, bronchoscopy and aerosol-inhalation scans often did not correlate, e. g. a bronchoscopically evident stenosis was not necessarily associated with an increased activity, and vice versa. Although peripheral mucociliary clearance was preserved after transplantation, stasis in central airways resulted in significantly impaired global clearance. Conclusion: Ventilation and perfusion scintigraphy reveal in a significant number of lung recipients pathologic findings and therefore can be recommended for postoperative monitoring. From a clinical point of view aerosol-inhalation scintigraphy (clearance) is not of any additional value.

Sentinel node biopsy in breast cancer

The international consensus conference from St. Gallen concerning the treatment of early breast cancer concluded in 2003, that sentinel node biopsy was now accepted as method allowing axillary staging in breast cancer. This procedure may avoid complete lymph node dissection in appropriate cases. Since numerous questions associated with the technique are still not defined and the procedure itself is not yet standardized, the German Society of Senology defined the conditions for the routine clinical use of sentinel node biopsy in an interdisciplinary consensus meeting.

Radiation exposure in 90Y-Zevalin therapy

Aim of this study was the assessment of the radiation exposure from preparation and application of 90Y-Zevalin, the measurement of the dose rate at the patient, the exposure of family members as well as the determination of the activity concentration in urine of patients. Methods: Overall data from 31 therapeutic administrations carried out in four institutions were evaluated. During preparation and application of 90Y-Zevalin the finger exposures of radiochemists, technicians, and physicians were measured. The dose rate of the patient was measured immediately after radioimmunotherapy. In patients treated in a nuclear medicine therapy unit, urine was collected over a two day period and the corresponding activity was determined. Family members of outpatients were asked to wear a dosimeter over a seven day period. Results: During the preparation we found a maximum skin dose of 6 mSv at the average, and during application of 3 mSv, respectively. After administration of 90Y the dose rate was 0.4±0.1 μSv/h at 2 m distance. Urine measurements yielded a cumulated 24 h excretion of 3.9±1.4% and 4.4±1.4% within 48 h, respectively, that is equivalent to 43±18 and 50±20 MBq of 90Y, respectively. Family members received a radiation exposure of 40±14 μSv over seven days. Conclusion: During preparation and application of 90Y-Zevalin appropriate radiation shielding is necessary. For family members as well as nursing staff no additional special radiation protection measures beyond those being common for other nuclear medicine procedures are necessary.

Nonspecific bowel activity in imaging inflammation with Tc-99m labelled monoclonal anti-NCA-90 Fab’ fragment MN3

Aim: Since the Tc-99m labelled monoclonal anti-NCA 90 granulocyte antibody Fab’ fragment MN3 (MN3 Fab’) might be of interest for imaging abdominal inflammation which could be hampered by nonspecific bowel activity, we prospectively investigated the appearance of bowel activity in MN3 Fab’ imaging. Methods: Eighty consecutive patients (age range 12-85 years) referred for suspected nonabdominal, mostly musculoskeletal infection, were included. Abdominal inflammation was excluded clinically and there were no signs of inflammatory bowel disease in the patients’ histories. One, 5, and 24 hours after intravenous injection of up to 1.1 GBq of MN3 Fab’ planar images of the abdomen were performed. Bowel activity was graded visually using a 5-point scale. Results: The one (N = 80), 5 (N = 79), and 24 (N = 52) hour images revealed 46 (10%), 162 (34%), and 173 (55%) accumulating bowel segments, respectively, in 37 (46%), 69 (87%), and 52 (100%) patients. The mean intensity score per accumulating segment was 1.1,1.8 and 2.7 (p = 0), respectively. Relative frequencies of appearance of the small intestine were 38%, 57%, and 21%, ileocaecal region 6%, 53%, and 48%, ascending colon 5%, 67%, and 89%, transverse colon 1%, 9%, and 69%, descending colon 8%,15 %, and 67%, and rectosigmoid 0%, 4%, and 38%, respectively. Follow-up investigations in 13 patients revealed diverging uptake patterns. Conclusion: Nonspecific bowel activity is often present in the early and almost always and more intense, in the delayed images. Early imaging at one hour after administration seems feasible, but a loss in sensitivity has to be considered. Thus, nonspecific bowel activity can be anticipated to be a pitfall in imaging abdominal inflammation with MN3 Fab’.

The Use of Radiolabelled Human Serum Albumin and SPECT/MRI Co-Registration to Study Inflammation in The Cavernous Sinus of Cluster Headache Patients

A sterile inflammation in the cavernous sinus was hypothesized to underlie cluster headache (CH). Neurogenic inflammation is accompanied by the extravasation of plasma proteins in the surrounding tissue. We tested the hypothesis of an inflammatory process in the cavernous sinus in CH patients using 99mTc-human serum albumin (HSA) and single photon emission computed tomography (SPECT). Six patients with episodic CH were enrolled. After baseline imaging, CH attacks were induced by IV injection of nitroglycerin. The patients remained untreated for 20 min. A second SPECT was performed after successful treatment. Region of interest (ROI) analysis was performed on the basis of coregistered MRI/SPECT data. There was no statistical difference between the 99mTc-HSA uptake in the ipsilateral cavernous sinus before and after induction of an acute CH attack. There was no evidence for 99mTc-HSA extravasation in the cavernous sinus during the active episode as compared with the remission phase. Our results do not support the hypothesis of an inflammation in the cavernous sinus.

Combined thallium-201 and dynamic iodine-123 iodophenylpentadecanoic acid single-photon emission computed tomography in patients after acute myocardial infarction with effective reperfusion

BACKGROUND

Considerable derangements of energy metabolism are to be expected during ischemia and reperfusion. In ischemic myocardium, the oxidative degradation of carbohydrates is shifted toward the anaerobic production of lactate and the oxidation of fatty acids is suppressed.

HYPOTHESIS

The aim of this study was to examine the uptake and metabolism of iodine-123 (123I) iodophenylpentadecanoic acid (IPPA) in stunned myocardium.

METHODS

In 15 patients, SPECT with 201Tl and 123I IPPA as well as echocardiography with low-dose dobutamine stimulation were performed 12 +/- 5 days after myocardial infarction with reperfusion. Follow-up echocardiography was carried out 24 +/- 8 days later for documentation of functional improvement. Uptake of 201Tl and 123I IPPA were obtained in five left ventricular segments, and dynamic SPECT imaging was used for calculation of the fast and the slow components of the biexponential myocardial 123I IPPA clearance.

RESULTS

Wall motion improved in 14 of 26 dysfunctional segments (54%). Stunned segments were characterized by a reduced 123I IPPA extraction, a shorter half-life of the fast, and a longer half-life of the slow clearance component. All parameters of the combined 201Tl/123I IPPA study predicted functional recovery with similar accuracies (area under the receiver operator characteristic curves between 0.68 and 0.76; p = NS). Analysis of 201Tl uptake alone could not predict functional recovery in this study.

CONCLUSIONS

Stunned myocardium is characterized by a disturbance of fatty acid metabolism. For prediction of functional improvement, 123I IPPA imaging added significant diagnostic information.

Yttrium-90-labeled ibritumomab tiuxetan for primary CNS lymphoma

11512

Background: Salvage treatment has not yet been established in primary CNS lymphoma (PCNSL). Here we report first results of an ongoing phase II study with a single treatment course of Y-90 anti-CD20 antibody ibritumomab tiuxetan in relapsed/resistant PCNSL. Methods: Eligibility criteria include histologically confirmed, recurrent PCNSL after at least one prior treatment, HIV negativity and adequate bone marrow and cardiac function. Primary endpoint is overall response, secondary endpoints are response duration, survival, and toxicity including late neurotoxicity. Treatment includes rituximab 250 mg/m2 on day -7 and day 0, followed by Y-90-ibritumomab tiuxetan 15 MBq/kg IV. Response evaluation by contrast-enhanced magnetic resonance imaging (MRI) and fluorodeoxyglucose positron emission tomography (FDG-PET) is scheduled before, one month and two months after treatment as well as every three months thereafter in responders. In two patients single photon emission computed tomography (SPECT) target imaging with gamma-emitting 111-Indium-ibritumomab tiuxetan was performed repeatedly. Results: To date, four patients have been enrolled. Complete response on MRI and decreased but still detectable FDG-uptake in PET was seen in one patient; the response duration was one month. In another patient uncertain complete response with minimal residual contrast enhancement lasting 12+ months was observed. Two patients had disease progression. One patient developed CTC grade 3 pneumonia during CTC grade 2 leukopenia, two patients had CTC grade 3 thrombocytopenia lasting up to 6 weeks. SPECT indicated target accumulation in the tumor starting 48 hours and still ongoing 7 days after injection of 111-Indium-ibritumomab tiuxetan. Conclusions: This is the first report on a successful treatment of PCNSL with Y-90-ibritumomab tiuxetan and penetration of a therapeutic antibody into PCNSL, warranting further investigation.

No significant financial relationships to disclose.

Allogeneic hematopoietic cell transplantation following conditioning with 90Y-ibritumomab-tiuxetan

Radioimmunotherapy (RIT) of relapsed lymphoma is gaining increasing importance. Especially the commercially available anti-CD20 antibody 90Y-ibritumomab tiuxetan is currently under investigation in various trials including dose escalation and autologous hematopoietic progenitor cell support. It is not clear, however, whether the implementation of this radiolabeled antibody into another treatment option for relapsed or poor risk lymphoma patients-allogeneic hematopoietic cell transplantation-interferes with or delays successful engraftment. This study reports encouraging results with 2 relapsed lymphoma patients (1 transformed marginal zone lymphoma and 1 mantle cell lymphoma) who underwent allogeneic hematopoietic cell transplantation from HLA-matched donors. The conditioning regimen consisted of Rituximab 250 mg m(-2) on days -21 and -14, 0.4 mCi kg(-1) body weight 90Y-ibritumomab tiuxetan on day -14 and fludarabine (30 mg m(-2)) plus cyclophosphamide (500 mg m(-2)) on days -7 to -3. The data demonstrate that engraftment is fast and reliable with leukocytes >1 x 10(9) L(-1) on day 12 and platelets >50 x 10(9) L(-1) on day 10. Thus, the incorporation of radioimmunotherapy into allogeneic transplant protocols combines established modalities with proven anti-lymphoma activity and, hence, offers an attractive new therapeutic option for relapsed lymphoma patients.

[Radiation exposure in (90)Y-Zevalin therapy: results of a prospective multicentre trial]

AIM of this study was the assessment of the radiation exposure from preparation and application of (90)Y-Zevalin, the measurement of the dose rate at the patient, the exposure of family members as well as the determination of the activity concentration in urine of patients.

METHODS

Overall data from 31 therapeutic administrations carried out in four institutions were evaluated. During preparation and application of (90)Y-Zevalin the finger exposures of radiochemists, technicians, and physicians were measured. The dose rate of the patient was measured immediately after radioimmunotherapy. In patients treated in a nuclear medicine therapy unit, urine was collected over a two day period and the corresponding activity was determined. Family members of outpatients were asked to wear a dosimeter over a seven day period.

RESULTS

During the preparation we found a maximum skin dose of 6 mSv at the average, and during application of 3 mSv, respectively. After administration of (90)Y the dose rate was 0.4 +/- 0.1 microSv/h at 2 m distance. Urine measurements yielded a cumulated 24 h excretion of 3.9 +/- 1.4% and 4.4 +/- 1.4% within 48 h, respectively, that is equivalent to 43 +/- 18 and 50 +/- 20 MBq of (90)Y, respectively. Family members received a radiation exposure of 40 +/- 14 microSv over seven days.

CONCLUSION

During preparation and application of (90)Y-Zevalin appropriate radiation shielding is necessary. For family members as well as nursing staff no additional special radiation protection measures beyond those being common for other nuclear medicine procedures are necessary.

Scintigraphic results in patients with lung transplants: a prospective comparative study

AIM

We addressed the feasibility of scintigraphy in the postoperative monitoring of lung transplants.

METHOD

37 patients (22 women, 15 men, 37 +/- 15 years) in good clinical condition were examined after lung transplantation. Scintigraphic procedures for assessing ventilation (133Xe), perfusion (99mTc microspheres) and aerosol-inhalation (99mTc aerosol) were performed for all patients. The findings were compared with those of established diagnostic modalities.

RESULTS

All lung transplants showed homogeneous ventilation but with a non-physiologic difference of over 20% between both pulmonary lobes in one-third of the cases. There was a difference between the impairement of perfusion and ventilation in the presence of an impaired Euler-Liljestrand reflex in 14/37 (38%) patients. Furthermore, bronchoscopy and aerosol-inhalation scans often did not correlate, e. g. a bronchoscopically evident stenosis was not necessarily associated with an increased activity, and vice versa. Although peripheral mucociliary clearance was preserved after transplantation, stasis in central airways resulted in significantly impaired global clearance.

CONCLUSION

Ventilation and perfusion scintigraphy reveal in a significant number of lung recipients pathologic findings and therefore can be recommended for postoperative monitoring. From a clinical point of view aerosol-inhalation scintigraphy (clearance) is not of any additional value.

[Sentinel node biopsy in breast cancer]

The international consensus conference from St. Gallen concerning the treatment of early breast cancer concluded in 2003, that sentinel node biopsy was now accepted as method allowing axillary staging in breast cancer. This procedure may avoid complete lymph node dissection in appropriate cases. Since numerous questions associated with the technique are still not defined and the procedure itself is not yet standardized, the German Society of Senology defined the conditions for the routine clinical use of sentinel node biopsy in an interdisciplinary consensus meeting.

Bildgebende Verfahren in der Rheumatologie: Szintigraphie bei rheumatoider Arthritis

Bone scintigraphy is an important tool for staging and follow-up in patients with rheumatoid arthritis, and is part of the training for board certified physicians in nuclear medicine in Germany. Bone scintigraphy uses the accumulation of i.v. injected technetium-99m labeled phosphonates imaged with a gamma camera. Different phases can be defined: perfusion phase (0-60 s p. i.), blood pool phase (2-5 min p. i.), and bone (turnover) phase (2-5 h p. i.). The blood pool phase allowes judgement of inflammatory (soft tissue) components of joint disease ("arthritis"), the bone (turnover) phase of longer lasting bone processes ("arthrosis"). The technical details including documentation of the scintigraphic results are presented according to the procedure guidelines of the German Society of Nuclear Medicine (www.nuklearmedizin. de).

[Differentiation between vital heart muscle tissue and infarct scar using magnetocardiography]

Magnetocardiography provides touchless information about myocardial excitation propagation and repolarization. This evolving diagnostic technique has been used so far to risk-stratify patients in terms of sudden cardiac death and to detect myocardial ischemia. We evaluated its potential to assess myocardial viability in patients with coronary artery disease. Magnetocardiography was performed using a shielded prototype 49-channel LTS SQUID system. A specific algorithm was developed to calculate automatically a set of magnetocardiographic parameters. Regional myocardial viability was determined using 18F-labeled fluoro-2-deoxyglucose positron emission tomography. We found that magnetocardiography may contribute essentially to discriminate between viable myocardium and infarct scar.

Temporary shielding of hot spots in the drainage areas of cutaneous melanoma improves accuracy of lymphoscintigraphic sentinel lymph node diagnostics

Detection of the "true" sentinel lymph nodes, permitting correct staging of regional lymph nodes, is essential for management and prognostic assessment in malignant melanoma. In this study, it was prospectively evaluated whether simple temporary shielding of hot spots in lymphatic drainage areas could improve the accuracy of sentinel lymph node diagnostics. In 100 consecutive malignant melanoma patients (45 women, 55 men; age 11-91 years), dynamic and static lymphoscintigraphy in various views was performed after strict intracutaneous application of technetium-99m nanocolloid (40-150 MBq; 0.05 ml/deposit) around the tumour (31 patients) or the biopsy scar (69 patients, safety distance 1 cm). The images were acquired with and without temporary lead shielding of the most prominent hot spots in the drainage area. In 33/100 patients, one or two additional sentinel lymph nodes that showed less tracer accumulation or were smaller (<1.5 cm) were detected after shielding. Four of these patients had metastases in the sentinel lymph nodes; the non-sentinel lymph nodes were tumour negative. In 3/100 patients, hot spots in the drainage area proved to be lymph vessels, lymph vessel intersections or lymph vessel ectasias after temporary shielding; hence, a node interpreted as a non-sentinel lymph node at first glance proved to be the real sentinel lymph node. In two of these patients, lymph node metastasis was histologically confirmed; the non-sentinel lymph nodes were tumour free. In 7/100 patients the exact course of lymph vessels could be mapped after shielding. In one of these patients, two additional sentinel lymph nodes (with metastasis) were detected. Overall, in 43/100 patients the temporary shielding yielded additional information, with sentinel lymph node metastases in 7%. In conclusion, when used in combination with dynamic acquisition in various views, temporary shielding of prominent hot spots in the drainage area of a malignant melanoma of the skin leads to an improvement in the accuracy of identification and localisation of sentinel lymph nodes by lymphoscintigraphy.

Bone marrow immunoscintigraphy in haematological patients with pancytopenia: preliminary results

The aim of this study was to assess the clinical value of bone marrow immunoscintigraphy using the (99m)Tc labelled anti-NCA-95 antigranulocyte antibodies (AGAb) and of AGAb bone marrow uptake ratio (UR) in the initial diagnostic work-up of diseases with depression of the bone marrow. Twenty-four whole-body bone marrow scans were performed in 23 patients (11 women, 12 men; median age 46 years, range 17-74 years) 5 h after i.v. injection of 370 MBq of AGAb. The UR was calculated from the posterior view drawing an irregular region of interest around the sacroiliac and a background areas. The mean UR in pancytopenic patients was 2.3+/-1.5 (range 0.3-5.8), thus being significantly lower (P=0.45 x 10(-6)) than the mean UR in a control group of 50 patients (mean UR 7.3+/-2.3; range 4.4-12.6) obtained previously. Considering patient age, there was no overlap between UR of pancytopenic patients and the respective normal ranges. The bone marrow appearance on scans seemed to be characteristic for the different haematological diseases investigated. In six patients with myelofibrosis, bone marrow scans demonstrated diffusely decreased bone marrow activity and prominent splenic uptake, possibly related to extramedullary haematopoiesis. In aplastic anaemia, highly reduced and patchy marrow uptake was observed in four patients (five scans), in one of them persisting even after blood cell counts had recovered to the near-normal range. In another two patients with aplastic anaemia, diffusely decreased bone marrow uptake was obtained. In patients with myeloid leukaemia, bone marrow patterns were almost normal probably because the target antigen is often expressed on neoplastic myeloid cells, too. Bone marrow extension was a common finding in these patients. There is an obvious differentiation between haematological patients with pancytopenia and normal subjects by means of AGAb bone marrow uptake ratio. The distinct patterns of AGAb distribution may be indicative for particular haematological diseases.

Imaging of low-grade bone infection with a technetium-99m labelled monoclonal anti-NCA-90 Fab' fragment in patients with previous joint surgery

Low-grade bone infection represents a serious clinical problem. Diagnostic options are often insufficient, yet the therapeutic implications of proven disease are important, especially in patients with prosthetic joint replacement. Technetium-99m labelled monoclonal anti-NCA-90 granulocyte antibody Fab' fragment (MN3 Fab') has been shown to be useful in bone and joint infection, but there are no data specifically referring to low-grade bone infection. We therefore analysed 38 scans in 30 consecutive patients (age range, 30-85 years; median age, 62 years) referred for suspected low-grade bone infection. There were 17 patients (21 scans) with total hip arthroplasty (THA), six with total knee arthroplasty (TKA), three who had undergone hip or knee surgery for trauma and five (seven scans) with resected hips and no endoprostheses (Girdlestone situations); one of these five patients had been investigated before with THA in situ and another prior to surgery for low-grade coxitis. There were no patients with rheumatoid arthritis as the underlying disease. Results were verified by means of bacteriological cultures, histopathological findings and/or follow-up and compared with the respective Zimmerli scores, which were used for clinical assessment of inflammatory activity. In one patient, the final diagnosis could not be established. One, 5 and 24 h after intravenous injection of up to 1.1 GBq of MN3 Fab', whole-body and planar scans were performed using a dual-head gamma camera. Scans were analysed visually and semiquantitatively adopting an arbitrary score ranging from 0 to 3. There were 13 true positive, 14 true negative and 10 false positive outcomes, yielding an overall sensitivity of 100%, an overall specificity of 58%, an accuracy of 73% and positive and negative predictive values of 57% and 100%, respectively. In patients with THA or TKA, accuracy was 81% and 80%, respectively, while it dropped to 43% in patients with Girdlestone situations owing to a high proportion of false positive findings (4/7) in this subgroup. Scintigraphic score was 1 in all of the false positive and in 11/13 true positive findings. The two remaining true positive findings displayed scintigraphic scores of 2 and 3, respectively. Scintigraphic and Zimmerli scores were loosely correlated (Spearman rho=0.38, P<0.05). Infection was excluded in 22/24 investigations with Zimmerli scores of <6. In this group, there were 13 scintigraphically true negative, nine false positive outcomes, and just two true positive outcomes. In 11/12 investigations with Zimmerli scores of 6 or 7, infection was verified and scintigraphic outcome was accordingly true positive, while the remaining patient was true negative. In conclusion, MN3 Fab' scintigraphy proved to be highly sensitive but not specific in diagnosing low-grade infections of the hip and knee regions in patients with previous joint surgery. The method seems reliable in excluding but not in proving the presence of infection. MN3 Fab' scintigraphy should not be applied in patients with Girdlestone situations. Assessment of infection using the Zimmerli score was more reliable than MN3 Fab' scintigraphy in this group of patients without rheumatoid arthritis as the underlying disease. Considering results from the literature concerning leucocyte scintigraphy, MN3 Fab' scintigraphy may be clinically useful in evaluating low-grade bone infection in THA and TKA patients with Zimmerli scores above 5 and concomitant rheumatoid arthritis or other inflammatory diseases.

Bone marrow scintigraphy with 99m Tc labelled monoclonal anti-NCA 90 Fab' fragment: a feasibility study and comparison of bone marrow uptake with 99m Tc labelled monoclonal anti-NCA 95 antigranulocyte antibody

The aim of this retrospective study was to evaluate the usefulness of 99mTc labelled monoclonal anti-NCA 90 antigranulocyte antibody Fab' fragment (MN3 Fab') as a bone marrow imaging agent. One hundred and ten planar scans (88 patients) of the lumbar and sacroiliac regions as well as whole-body scans were performed after 1, 5 and 24 h. All the scans were evaluated visually and bone marrow uptake was determined semiquantitatively as count density ratio from sacroiliac-minus-background to background area. Results were compared to 50 age-matched patients with normal bone marrow scans obtained with the intact 99mTc labelled monoclonal anti-NCA 95 antigranulocyte antibody (BW 250/183) in a previous study. Seventy-three patients showed a physiological activity distribution in the central bone marrow. Ten patients showed a bone marrow extension, while in two patients central bone marrow depression was observed. Evaluation of the ribs, lower thoracic and upper lumbar spine was hampered by soft-tissue activity. Bone marrow uptake was 1.36+/-0.56 after 1 h, decreased thereafter and was significantly lower than that of BW 250/183 (P < 0.001). In conclusion, MN3 Fab' cannot be recommended for bone marrow scintigraphy, because relevant parts of the haemopoietically active bone marrow are not accessible to visual evaluation. A significant role of the semiquantitative evaluation of MN3 Fab' bone marrow uptake in patients with potential marrow depression seems unlikely.

Extraction of long-chain fatty acids in isolated rat heart during acute low-flow ischemia

Although beta-oxidation of fatty acids is suppressed rapidly during ischemia, the behavior of fatty acid extraction at different flow rates is incompletely understood. This study assessed the relationship between flow and extraction of (123)I-iodophenylpentadecanoic acid (IPPA) in the isolated heart model, especially at low flow.

METHODS

Isolated hearts from male Wistar rats (n = 15) were subjected to retrograde perfusion with constant flow (Krebs Henseleit solution containing 10 mmol/L glucose). A latex balloon in the left ventricle allowed isovolumetric contractions and ventricular pressure measurements. The extraction of (123)I-IPPA was assessed with the indicator dilution technique and (99m)Tc-albumin as the intravascular reference. The flow was either increased from the control flow (8 mL/min) until 300% or reduced until 10%. (123)I-IPPA extraction was measured three times before and 10 min after flow alteration. The tracer uptake was estimated from the product of net extraction and flow.

RESULTS

The mean (123)I-IPPA extraction at the control flow (third measurement) was 51.6% +/- 2.8%. Between flow rates of approximately 25% and 300%, (123)I-IPPA extraction increased exponentially at decreasing flow rates. At flow rates < or =25% of the control flow, (123)I-IPPA extraction was exponentially higher than predicted. (123)I-IPPA uptake and flow changed largely in parallel. During low flow, the rate-pressure product showed the expected decline (perfusion-contraction matching).

CONCLUSION

The extraction of (123)I-IPPA is preserved and slightly increased (relative to flow) during acute low-flow ischemia.

Nonspecific bowel activity in imaging inflammation with Tc-99m labelled monoclonal anti-NCA-90 Fab' fragment MN3

AIM

Since the Tc-99m labelled monoclonal anti-NCA 90 granulocyte antibody Fab' fragment MN3 (MN3 Fab') might be of interest for imaging abdominal inflammation which could be hampered by nonspecific bowel activity, we prospectively investigated the appearance of bowel activity in MN3 Fab' imaging.

METHODS

Eighty consecutive patients (age range 12-85 years) referred for suspected nonabdominal, mostly musculoskeletal infection, were included. Abdominal inflammation was excluded clinically and there were no signs of inflammatory bowel disease in the patients' histories. One, 5, and 24 hours after intravenous injection of up to 1.1 GBq of MN3 Fab' planar images of the abdomen were performed. Bowel activity was graded visually using a 5-point scale.

RESULTS

The one (N = 80), 5 (N = 79), and 24 (N = 52) hour images revealed 46 (10%), 162 (34%), and 173 (55%) accumulating bowel segments, respectively, in 37 (46%), 69 (87%), and 52 (100%) patients. The mean intensity score per accumulating segment was 1.1, 1.8 and 2.7 (p = 0), respectively. Relative frequencies of appearance of the small intestine were 38%, 57%, and 21%, ileocaecal region 6%, 53%, and 48%, ascending colon 5%, 67%, and 89%, transverse colon 1%, 9%, and 69%, descending colon 8%, 15%, and 67%, and rectosigmoid 0%, 4%, and 38%, respectively. Follow-up investigations in 13 patients revealed diverging uptake patterns.

CONCLUSION

Nonspecific bowel activity is often present in the early and almost always and more intense, in the delayed images. Early imaging at one hour after administration seems feasible, but a loss in sensitivity has to be considered. Thus, nonspecific bowel activity can be anticipated to be a pitfall in imaging abdominal inflammation with MN3 Fab'.

Endoscopic sentinel node detection with a gamma probe combined with minimally invasive axillary lymph node dissection: a preliminary study

OBJECTIVE

To investigate the efficacy of videoendoscopic axillary lymph node dissection combined with endoscopic sentinel node detection by gamma probe and preoperative sentinel node imaging.

DESIGN

Open study.

SETTING

University hospital, Germany.

SUBJECTS

Four patients with breast cancer.

INTERVENTION

Injection of 99mTc-nanocolloid around the tumour.

RESULTS

In three patients axillary sentinel nodes were detected both before and after operation. In the remaining one it was not found. In two patients the minimally invasive approach had to be converted to conventional open surgery because of anatomical restrictions.

CONCLUSION

We describe a new approach that uses a minimally invasive technique and endoscopic radioguided sentinel node biopsy in patients with breast cancer. The results of this preliminary study warrant further investigation.

Regional cerebral glucose metabolism in healthy volunteers determined by fluordeoxyglucose positron emission tomography: appearance and variance in the transaxial, coronal, and sagittal planes

PURPOSE

In this study, the contribution of the transaxial, coronal, and sagittal planes in evaluations of regional cerebral glucose metabolism was investigated in healthy volunteers as determined by fluorine-18-labeled 2-deoxy-2-fluoro-D-glucose (FDG) and high-resolution positron emission tomography (PET).

METHODS

One hundred twenty-seven healthy right-handed volunteers were injected with 4.2 MBq/kg (0.11 mCi) body weight FDG and imaged in a PENN PET H 240 scanner. Images were corrected for scatter and random coincidences and reconstructed in all three planes into 6- to 8-mm-thick slices. The reconstructed images were corrected for attenuation using the Chang algorithm. The transverse, coronal, and sagittal images were read independently of each other using a qualitative scale in which 1 = equal to, 2 = mildly, 3 = moderately, and 4 = markedly less than the area with the highest glucose metabolism in the respective plane.

RESULTS

The areas with the highest glucose metabolisms were the posterior cingulate gyri with mean scores of 1.1 to 1.2, thalami (1.2 to 1.3), basal ganglia (1.5 to 1.9), and visual cortex (1.6). The lowest values were found in the occipital cortex (2.7 to 2.8) and the cerebellum (2.3 to 2.4). Whereas reliable analysis of the mesial temporal aspects was not feasible in the sagittal plane, the anterior poles of the temporal and frontal lobes could not be evaluated in the coronal or the inferior temporal areas in the transaxial slices. In all three planes, regional glucose metabolism was less in the lateral temporal areas on the left than on the right (P < 0.001). The consistency of readings as measured in terms of coefficients of variation was greatest in the coronal plane for the caudates and posterior cingulate gyri, in the transaxial plane for the lateral temporal regions, and in the sagittal plane for the visual cortex. Age-dependent decreases in regional glucose metabolism in the inferior and lateral frontal regions and the parietal lobes were found in all three planes.

CONCLUSIONS

All three projection planes must be used for a comprehensive qualitative evaluation of the regional glucose metabolism of the brain.

Classification of the lymphatic drainage status of a primary tumour: a proposal

AIM

Creation of a classification of the lymphatic drainage status of a primary tumour. It shall enable comparison of different approaches, standardization and quality control.

METHODS

Identification and topographic localization of the sentinel node(s) using lymphatic radionuclide gamma camera imaging and/or gamma probe detection and/or vital dye mapping.

RESULTS

A classification comprising four classes (D-Class I-IV) and distinct subclasses (A-E) proved to be simply to be learned and applicable as well as reliably reproducible. It is based on the number of sentinel lymph nodes and their locations and can be combined with the pathological and molecular biological lymph node status. D-classes/subclasses obtained in 420 patients with malignant melanoma of the skin are presented.

CONCLUSIONS

The classification is applicable to different approaches. Its diagnostic, therapeutic and prognostic value should be studied prospectively in those primary tumours which preferably metastasis via their draining lymphatic vessels.

Recovery correction for quantitation in emission tomography: a feasibility study

In emission tomography, the spread of regional tracer uptake to surrounding areas caused by limited spatial resolution of the tomograph must be taken into account when quantitating activity concentrations in vivo. Assuming linearity and stationarity, the relationship between imaged activity concentration and true activity concentration is only dependent on the geometric relationship between the limited spatial resolution of the tomograph in all three dimensions and the three-dimensional size and shape of the object. In particular it is independent of the type of object studied. This concept is characterized by the term "recovery coefficient". Recovery effects can be corrected for by recovery coefficients determined in a calibration measurement for lesions of simple geometrical shape. This method works on anatomical structures that can be approximated to simple geometrical objects. The aim of this study was to investigate whether recovery correction of appropriate structures is feasible in a clinical setting. Measurements were done on a positron emission tomography (PET) scanner in the 2D and 3D acquisition mode and on an analogue and digital single-photon emission tomography (SPET) system using commercially available software for image reconstruction and correction of absorption and scatter effects. The results of hot spot and cold spot phantom measurements were compared to validate the assumed conditions of linearity and stationarity. It can be concluded that a recovery correction is feasible for PET scanners down to lesions measuring about 1.5xFWHM in size, whereas with simple correction schemes, which are widely available, an object-independent recovery correction for SPET cannot be performed. This result can be attributed to imperfections in the commercially available methods for attenuation and scatter correction in SPET, which are only approximate.

Intraindividual Comparison of F-18-Fluorodeoxyglucose and Tc-99m-Tetrofosmin in Planar Scintimammography and SPECT

Since the comparative value of several nuclear medicine investigations for breast cancer has not been established, the rationale of this study was to examine the diagnostic performances of F-18-fluorodeoxyglucose (FDG) and Tc-99m-tetrofosmin both in single photon emission computed tomography (SPECT) and planar technique in an intraindividual comparative study.A total of 54 patients with suspected breast cancer (48 malignant and 9 benign lesions) was investigated by planar and SPECT imaging with both FDG and tetrofosmin within the last preoperative week. Pathohistological confirmation of the diagnosis was obtained in all patients.2 cm 81%/67%, 92%/67%, 75%/50%, and 75%/100%. Sensitivity was higher with FDG SPECT than with the other imaging modalities and significantly lower for tumors </=2 cm with all the techniques investigated. In 20 out of 21 patients with diverging scintigraphic findings, FDG SPECT was either true positive or true negative. In 15 patients with axillary lymph node metastases, sensitivities were 33%, 73%, 36%, and 50%, respectively.2 cm, if dedicated PET is not available.

Nuclear medicine imaging of endocarditis

Infective endocarditis is a serious disease which requires early diagnosis and adequate therapy. Echocardiography plays a key role in diagnosis and follow-up. Subacute infective endocarditis, however, is often difficult to prove echocardiographically due to its more subtle morphological changes. Also, echocardiography cannot reliably differentiate florid vegetations from residual structural changes of the affected valves in cured patients. Therefore, scintigraphy of infection and inflammation, a functional imaging procedure, has been investigated as a complementary tool in diagnosis and follow-up of infective endocarditis. So far, results obtained with Gallium-67 scintigraphy are not convincing, although an improvement by using modern acquisition techniques seems possible. Scintigraphy with Indium-111 labelled leukocytes has an unacceptably low sensitivity, which is probably due to the small number of cells involved and unfavourable imaging characteristics of 111In-Technetium-99m labelled leukocytes have been investigated in few patients, so final judgement is not yet possible. SPECT imaging might enhance the detectability of diseased heart valves. Immunoscintigraphy with the 99mTc labelled antigranulocyte antibody in SPECT technique is complementary to echocardiography and seems to assess the floridity of the underlying inflammatory process. The combined use of both imaging modalities allows detection of virtually all cases of subacute infective endocarditis. SPECT immunoscintigraphy with the antigranulocyte antibody seems useful in doubtful cases of infective endocarditis, especially, if echocardiography is non-diagnostic and valve pathology pre-existing. The method may be used for follow-up and monitoring antibiotic therapy.

Scintigraphic localization of lymphatic leakage site after oral administration of iodine-123-IPPA

Chylothorax can occur secondary to traumatic lesions of the thoracic duct caused by chest injuries, surgical procedures involving the pleural space, neoplasms or malformations of the lymphatics.

METHODS

Lymphatic leakage sites were localized by scintigraphy after oral administration of the 123I-labeled long-chain fatty acid derivative iodophenyl pentadecanoic acid (IPPA). We report on three patients with different lymphatic leakage sites and on one normal control subject.

RESULTS

IPPA scintigraphy localized the lymphatic leakage site correctly in all three patients. In two of them, the method even guided the successful surgical treatment of the leakage.

CONCLUSION

This approach is suitable for detecting lymphatic leakages of intestinal origin.

Clinical value of immunoscintigraphy in patients with fever of unknown origin

The aim of our study was to evaluate the clinical value of immunoscintigraphy with the monoclonal antibody 99mTc-BW 250/183 in patients with fever of unknown origin (FUO). The antibody BW 250/183 is an immunoglobulin G1 subtype that binds to the antigen NCA-95, which is expressed on the cell membrane surface of granulocytes.

METHODS

We studied 51 patients who were referred with the diagnosis of FUO. Thirty-five percent of the patients suffered from infection, 17% had autoimmune diseases, 14% had neoplasms and 8% had other diseases. The remaining 28% of the patients did not have a diagnosis. Planar imaging was performed in all patients, and 19 patients underwent SPECT. In our analysis, both cold and hot spots were considered diagnostic.

RESULTS

Pyogenic infections were visualized correctly in 13 foci. The diagnosis of endocarditis (n = 4) could be determined only by SPECT. False-negative results were found in 4 patients and false-positive uptake was seen in 2 patients. No false-positive uptake or cold spots in the central bone marrow were found in patients with viral, granulomatous and autoimmune diseases or in those patients in whom no FUO cause was found in a 6-mo follow-up. In these patients, a negative scan did not change their diagnostic work-up. Cold spots in the central bone marrow were correctly interpreted in 5 of 6 patients. Sensitivity in detecting pyogenic foci was 73% and specificity was 97%. Positive and negative predictive values were 93% and 87%, respectively. Including areas of decreased uptake in the analysis, sensitivity for detecting an underlying inflammatory or malignant process for FUO was 81 % and specificity was 87%. Positive and negative predictive values were 81% and 87%, respectively.

CONCLUSION

Immunoscintigraphy with 99mTc-BW 250/183 in patients with FUO has clinical potential for the diagnosis and exclusion of pyogenic causes of FUO. Metastatic malignant disease and high-grade spondylodiskitis could be diagnosed early in a diagnostic work-up by a characteristic cold spot pattern in the bone marrow. SPECT is indispensible for scintigraphic imaging of endocarditis.

[Septal myocardial perfusion in complete left bundle branch block: case report and review of the literature]

Myocardial scintigraphy was performed three times in a 55-year-old woman with left bundle branch block (LBBB). A significant LAD stenosis had been excluded by coronary angiography. The first scintigraphy was performed with Tc-99m sestamibi after submaximal bicycle exercise and revealed a septal perfusion deficit. This deficit could not be reproduced in the following examinations after pharmacological stress testing with dipyridamole using both Tl-201 and Tc-99m sestamibi. Perfusion at rest assessed with Tl-201 was normal in all studies. It is concluded that pharmacological stress testing with dipyridamole is to be preferred in patients with LBBB. With respect to the accuracy of myocardial perfusion imaging the choice of the radiopharmaceutical plays a less important role.

Somatostatin receptor scintigraphy in small-cell lung cancer: results of a multicenter study

The aims of this study were to determine the accuracy of somatostatin receptor scintigraphy in the detection of the primary tumor and its metastases in small-cell lung cancer (SCLC) in a large patient population, and to investigate the course of somatostatin uptake in primary tumors during therapy.

METHODS

In a total of 100 patients, 134 examinations were performed. Twenty-seven of the patients were examined before and after chemotherapy. Planar whole-body images were acquired 4 hr and 24 hr after injection of approximately 200 MBq (111)In-pentetreotide. SPECT of the thorax was performed after 24 hr. Tumor-to-background (T/B) ratios for the primary tumor were averaged from anterior and posterior projections.

RESULTS

Compared to conventional investigations, somatostatin receptor scintigraphy (SRS) visualized the primary tumor with varying degrees of uptake in 96% of the examinations. Regional metastases and distant metastases were detected in 60% and 45% of the examinations, respectively. The uptake of the somatostatin analog by the primary tumor was significantly lower in the patients examined during chemotherapy as compared to those examined before treatment (T/B ratio = 1.94+/-0.79 versus 2.35+/-0.9, p < 0.005). A decrease in T/B ratio was noted in patients with remission at the time of SRS (from 2.40+/-1.56 to 1.63+/-0.72, p < 0.05). No difference in the pretreatment uptake of octreotide by the primary tumor was identified between patients with tumor progression and those with partial or complete remission.

CONCLUSION

Somatostatin receptor scintigraphy has a high sensitivity in the detection of the primary tumor in SCLC but fails in the detection of metastases. Thus, SRS does not provide useful information for staging of SCLC. Since somatostatin uptake by the primary tumor is affected by chemotherapy, it may be used to follow up on the course of SCLC.

Changes in perfusion pattern using ECD-SPECT indicate frontal lobe and cerebellar involvement in exercise-induced paroxysmal dystonia

The clinical features of exercise-induced paroxysmal dystonia (EPD) are delineated in a pedigree including two affected members (both male) showing an autosomal-dominant inheritance trait. Gait analysis using kinematic electromyography during the motor attacks revealed coactivation of antagonistic calf muscles characteristic of dystonia. In the interval, impaired muscular alternation was observed. To characterize further the pathophysiological basis of the condition, ictal and interictal cerebral perfusion SPECT studies using technetium 99m-ethyl cysteinate dimer (ECD) were performed to establish whether cortical hyperactivity indicative of epilepsy is present during the motor attacks and to identify regional changes in the ictal perfusion pattern that could indicate an anatomic structure relevant to the disease. During the motor attacks, decreased ictal perfusion of the frontal cortex was found in both patients. In contrast, increased cerebellar perfusion was observed. The perfusion of the basal ganglia also decreased. No cortical hyperperfusion indicative of an epileptic nature was seen. Cerebellar hyperactivity in connection with prominent frontal hypoactivity has also been described in both the idiopathic and the symptomatic forms of dystonia. Our findings therefore suggest that EPD represents a paroxysmal movement disorder rather than epilepsy. It is concluded that changes in frontal and in cerebellar function are relevant to the pathophysiology of EPD.

Anti-carcinoembryonic antigen antibodies versus somatostatin analogs in the detection of metastatic medullary thyroid carcinoma: are carcinoembryonic antigen and somatostatin receptor expression prognostic factors?

BACKGROUND

Surgery is currently the only potentially curative approach in the treatment of medullary thyroid carcinoma (MTC). In many instances however, postsurgically elevated or rising plasma calcitonin and/or carcinoembryonic antigen (CEA) levels indicate persistent metastatic disease, although conventional diagnostic procedures (computed tomography (CT), magnetic resonance imaging (MRI), and invasive venous catheterization) fail to localize the responsible lesions. Recently, anti-CEA antibodies and somatostatin analogs have shown promising results in the staging of MTC. The aim of this study was to compare the sensitivity of both methodologies, especially for the detection of occult MTC, and to assess whether there may be correlations between the scintigraphic behavior and the patients' prognosis.

METHODS

A total of 26 patients with medullary thyroid carcinoma were examined at our institution between 1977 and 1996. Ten of them had known disease, 14 had occult metastatic MTC, and 2 were free of disease at the time of presentation. Fourteen patients were investigated with anti-CEA monoclonal antibodies (MAbs) (receiving a total of 35 injections: clones BW431/26, BW431/31, IMACIS, or F023C5, labeled with 99mTc, (111)In or (131)I), and 8 patients were studied with (111)In-labeled octreotide. Two patients received potentially therapeutic doses of (131)I-labeled anti-CEA antibodies. All patients underwent conventional radiologic evaluation (ultrasonography, CT, and MRI) and/or biopsy within 4 weeks. Additional imaging was performed with 99mTc-(V)-DMSA, (131)I-metaiodobenzylguanidine, 201thallium chloride, 99mTc-methylene diphosphate, and/or 18F-fluorodeoxyglucose-positron emission tomography. Clinical follow-up was obtained.

RESULTS

All patients with established disease had elevated plasma CEA (range, 6.8-345 ng/mL; calcitonin levels between 92 and 11,497 pg/mL), whereas in 9 of 14 occult cases, levels were < or = 5 ng/mL (range, 0.6-829 ng/mL; calcitonin, 72-2920 pg/mL). In patients with known disease, the overall lesion-based sensitivity was 86% for the anti-CEA MAbs, whereas octreotide was unable to target any tumor in patients with rapidly progressing disease or distant metastases (overall sensitivity, 47%). In all patients with occult MTC, anti-CEA MAbs and octreotide were able to localize at least one lesion (patient-based sensitivity, virtually 100%). In patients with postsurgically persistent hypercalcitoninemia, cervical lymph nodes were identified as the most frequent site of metastases, whereas in patients with occult and slowly progressing disease several years after primary surgery, anti-CEA MAbs and octreotide showed bilateral involvement of mediastinal lymph nodes; however, tumor to nontumor ratios were usually higher with octreotide in these cases. With anti-CEA Mabs, the highest tumor to nontumor ratios were observed in clinically aggressive, rapidly progressing disease. The sensitivity of all other diagnostic modalities was, at < or = 50%, significantly lower. Indication for antitumor effects was observed in a patient receiving 65 mCi of (111)I-labeled F(ab')2 fragments of the clone F023C5.

CONCLUSIONS

For the detection of occult MTC, anti-CEA MAbs and octreotide seem to have a sensitivity that is superior to conventional diagnostic modalities, especially also when used in combination. Better detectability with anti-CEA antibodies (which may result in higher CEA expression) seems to be associated with more aggressively growing forms of MTC, whereas somatostatin receptor expression at normal CEA plasma levels and weaker MAb targeting may be associated with a more benign clinical course. This is in accordance with the study of Busnardo et al. (Cancer 1984; 53:278-85), who showed higher CEA serum levels to be associated with a worse prognosis, as well as with the in vitro findings of Reubi et al. (Lab Invest 1991;64:567-73), who demonstrated lower somatostatin receptor expression in less differentiated MTC. Fu

Immunoscintigraphy of the bone marrow: normal uptake values of technetium-99m-labeled monoclonal antigranulocyte antibodies

The aim of our study was to determine the normal range of the 99mTc-labeled anti-NCA 95 antigranulocyte antibody (AGAb) uptake in the bone marrow using the sacroiliac-to-background uptake ratio in the posterior view.

METHODS

We made 169 planar bone marrow scans on 162 patients who were each injected with 555 MBq AGAb. Fifty patients with the diagnosis of infection/pyrexia of unknown origin (PUO) and with completely normal bone marrow scintigraphy were defined as the normal group. Uptake ratios were calculated drawing irregular regions of interest around the sacroiliac and a background area, respectively.

RESULTS

The normal group revealed a mean uptake ratio of 7.3 +/- 2.3 (range 4.4-12.6). Similar uptake ratios were obtained in patients with the primary diagnosis of infection/PUO and bone marrow extension (7.4 +/- 2.2, range 4.2-11.7), suggesting that the bone marrow reacts on infection primarily by extension into the periphery, without any significant increase of the activity of the central hemopoietic/granulopoietic bone marrow. Mean uptake ratios also were not significantly different in patients with normal bone marrow scintigraphy and the primary diagnosis of solid malignant tumors, lymphomas and plasmacytomas, and in patients with focal lesions visible on bone marrow scintigraphy (soft tissue inflammation or cold lesions in the bone marrow but with normal sacroiliac regions). Mean uptake ratios in the normal group were significantly age related, amounting to 8.5 +/- 1.8, 7.5 +/- 1.9 and 6.1 +/- 2.0 in patients younger than 40 yr, between 40 and 59 yr, and 60 yr or older, respectively (p = 0.0025). The method revealed good inter- and intraobserver agreement with correlation coefficients of about r = 0.90 and r = 0.95, respectively. Inter- and intraobserver coefficients of variation were 6.6% and 4.6%, respectively.

CONCLUSION

Determination of the bone marrow uptake ratio is simple and reproducible. The normal values established in this study were age dependent, which has to be considered when interpreting bone marrow uptake ratios. The presence of infection/PUO, solid malignant tumors, lymphomas and plasmacytomas does not seem to alter the AGAb uptake ratio significantly. The most important application of the quantitative analysis of bone marrow scintigraphy could be the diagnosis and follow-up of diseases with depression of the central hemopoietic activity.

Somatostatin receptor scintigraphy in the staging of lymphomas

In this prospective study we evaluated the somatostatin receptor scintigraphy in the initial staging of 19 patients suffering from Hodgkin's (HD) and non-Hodgkin's lymphomas (NHL) and in the restaging of 16 patients. Scintigraphy was compared to the results of the methods applied for adequate staging of lymphoma patients in the large multicentre trials. Planar imaging and SPECT was performed after intravenous injection of 110 or 220 MBq of 111In-pentetreotide. The patient-based analysis yielded an overall sensitivity of 88%, contrasting lesion-based sensitivities of 57%, 35%, and 43% in HD, low-grade NHL and high-grade NHL, respectively. The best results were obtained in the head-and-neck region and the worst in the abdomen (sensitivities of 61% and 24%, respectively). Bone marrow infiltration was visible in 1/12 cases only. There was no significant difference between the outcomes of patients in the initial staging and restaging and no influence of the amount of injected radiopharmaceutical on the results. In terms of the Ann-Arbor classification, 10/35 patients were concordant whereas 22 were understaged and 3 overstaged scintigraphically. In conclusion, somatostatin receptor scintigraphy is not useful in the initial staging or restaging of malignant lymphomas, especially NHL, due to low lesion detection rates most probably because of low receptor densities. In addition, intraindividual heterogeneity of somatostatin receptor expression has to be considered.

Assessment of myocardial viability in persistent defects on thallium-201 SPECT after reinjection using gradient-echo MRI

This prospective study assessed myocardial viability in 30 patients with coronary heart disease and persistent defects despite reinjection on TI-201 single-photon computed tomography (SPECT). In each patient, three observers graded TI-201 uptake in 7 left ventricular wall segments. Gradient-echo magnetic resonance imaging in the region of the persistent defect generated 12 to 16 short axis views representing a cardiac cycle. A total of 120 segments were analyzed. Mean end-diastolic wall thickness and systolic wall thickening (+/-SD) was 11.5 +/- 2.7 mm and 5.8 +/- 3.9 mm in 48 segments with normal TI-201 uptake, 10.1 +/- 3.4 mm and 3.7 +/- 3.1 mm in 31 with reversible lesions, 11.3 +/- 2.8 mm and 3.3 +/- 1.9 mm in 10 with mild persistent defects, 9.2 +/- 2.9 mm and 3.2 +/- 2.2 mm in 15 with moderate persistent defects, 5.8 +/- 1.7 mm and 1.3 +/- 1.4 mm in 16 with severe persistent defects, respectively. Significant differences in mean end-diastolic wall thickness (p < 0.0005) and systolic wall thickening (p < 0.005) were found only between segments with severe persistent defects and all other groups, but not among the other groups. On follow-up in 11 patients after revascularization, 6 segments with mild-to-moderate persistent defects showed improvement in mean systolic wall thickening that was not seen in 6 other segments with severe persistent defects. These data indicate that most myocardial segments with mild and moderate persistent TI-201 defects after reinjection still contain viable tissue. Segments with severe persistent defects, however, represent predominantly nonviable myocardium without contractile function.