Traditional Acupuncture for Reflex Sympathetic Dystrophy: A Randomised, Sham-Controlled, Double-Blind Trial

Acupuncture has been suggested as helpful in reflex sympathetic dystrophy (RSD), but no controlled study has yet been published. The hypothesis of this randomised, double-blind, sham-controlled trial, therefore, was that traditional Chinese acupuncture improves subjective as well as objective signs in this condition. Patients were included when suffering from clinically and scintigraphically confirmed acute RSD of the upper or lower limb, with a history between one and four months. They were randomly assigned to either traditional acupuncture (group A) or sham acupuncture (group S). Treatments were applied five times a week for three weeks, each session lasting for 30 minutes. Both groups received identical standard treatments in addition. The primary outcome variable had been pre-defined to be pain, as measured by visual analogue scale assessed before each treatment. Subjective success was also recorded by the patients on a rating scale. Due to force of circumstances, only 14 patients were entered into the study, therefore no test statistics could be performed and the data was evaluated descriptively. At baseline, pain was almost identical in both groups. During the course of the study, patients in group A demonstrated a more pronounced reduction of pain: 28.6% ± 1.9 vs 17.9% ± 2.4 (Mean ± SEM). Similarly, subjective success was rated to favour traditional acupuncture. It is concluded that acupuncture may be useful in the management of pain in patients with acute RSD, but that the present results are not conclusive. Larger, rigorous studies are required to answer the question.

Conversion from mild cognitive impairment to dementia: influence of folic acid and vitamin B12 use in the VITA cohort

OBJECTIVE

Increased serum homocysteine and low folate levels are associated with a higher rate of conversion to dementia. This study examined the influence of vitamin B12/folic acid intake on the conversion from mild cognitive impairment (MCI) to dementia.

PARTICIPANTS

A community dwelling cohort of older adults (N=81) from the Vienna Transdanube aging study with MCI.

DESIGN

Prospective study with a retrospective evaluation of vitamin intake.

MEASUREMENTS

Laboratory measurements, brain magnetic resonance imaging, and cognitive functioning were assessed at baseline and at five-year follow-up.

RESULTS

The self-reported combined use of folic acid and vitamin B12 for more than one year was associated with a lower conversion rate to dementia. Serum levels of homocysteine and vitamin B12 as measured at baseline or at five years were not associated with conversion. Higher folate levels at baseline in females predicted a lower conversion rate to dementia. The assessment of brain morphological parameters by magnetic resonance imaging revealed higher serum folate at baseline, predicting lower medial temporal lobe atrophy and higher levels of homocysteine at baseline, predicting moderate/severe global brain atrophy at five years. Users of vitamin B12 or folate, independent of time and pattern of use, had lower grades of periventricular hyperintensities and lower grades of deep white matter lesions as compared to non-users.

CONCLUSIONS

These results from a middle European study support observations on the protective ability of folate in MCI patients with respect to conversion to dementia; they also point to a participation of homocysteine metabolism on processes associated with brain atrophy.

[Nuclear medicine in Europe: education]

The technical developments that have taken place in the preceding years (PET, hybrid imaging) have changed nuclear medicine. The future cooperation with radiologists will be challenging as well as positioning nuclear medicine in an European context. It can also be expected that education in nuclear medicine will undergo a harmonization process in the states of the European Union. In this paper, we describe how nuclear medicine education is organized in several European countries. We aim to stimulate constructive discussions on the future development of the specialization in nuclear medicine in Germany.

Medical preparedness in radiation accidents: a matter of logistics and communication not treatment!

The currently reactor wreckage in Fukushima raised the following important questions: Is our knowledge of the possible dangers of ionizing radiation sufficient to warrant special action? What is the role of the medical community in technical radiation accidents from Windscale to Fukushima? What is the role of the medical community in terrorist radiation attacks? Are we prepared for those challenges? How can medical services communicate information in the media framework? What have we learned recently? And, what should be improved? In this review of the current literature on ionizing radiation, we try to answer these questions. Our conclusion is that medical services have to improve their communication skills and convince the public that the dangers of ionizing radiation can be quantitated within certain limits to support a qualified discussion about its risks and benefits.

[Diagnostic reference value. Critical evaluation of the term with the example of nuclear medicine studies in Austria]

The aim of this study was to collect administered activities of important nuclear medicine diagnostic examinations and to identify frequencies as well as age distributions in the light of hybrid devices in Austria. Based on the survey data a re-evaluation of dose reference levels for nuclear medicine has been published in June 2010 in the novella of the Austrian Medical Radiation Protection Regulation (MedStrSchV) (8), also an estimate of the average individual doses of the total population. Accurate data on nuclear medicine studies of 34% of all Austrian nuclear medicine units could be collected.

RESULTS

Extrapolated there are about 150000 nuclear medicine examinations per year performed in Austria. The median age of patients is thereby 62 years. The results of this study resulted in 65% of the dose reference values to change, whereas 48% had to be revised downwards and 17% upwards. Additionally, 5 new reference values were included in the list; three more were taken out, however. The estimation of the individual effective patient dose for each offered examination was on average 4.7 mSv. An extrapolation based on the total exposure of the population with regard to uninvolved persons and children led to 0.07 mSv per year by nuclear medicine examinations.

CONCLUSION

The published diagnostic reference values correspond to the normal investigative practice in Austria and are compliant with most international recommendations. The term "optimal value" has been removed from the text of the law, because such wording would be misleading.

Tumor growth of suspected meningiomas in clinically healthy 80-year-olds: a follow up five years later

BACKGROUND

The incidence of clinically silent meningiomas in 75-year-old individuals was determined five years ago in the Vienna Transdanube Ageing Study (VITA). At the time a watch-and-wait approach was recommended in cases of incidentally discovered meningiomas.

METHODS

420 out of the initial cohort of 532 test persons underwent control investigations after 2.5 and 5 years. Six of the nine known tumors were measured again and the patients underwent clinical, neurological and psychological tests. Changes in tumor size were determined and all new tumors seen on MRI investigation were carefully reviewed.

RESULTS

Tumor growth was minimal in all six cases that were followed over the entire period. Two of the original meningioma patients had died and one patient had undergone tumor resection.

CONCLUSIONS

The watch-and-wait approach recommended after the VITA study was confirmed by the present investigation. Tumor growth was slow in all cases; no clinical symptoms have been registered thus far. The intervals between control investigations may even be prolonged depending on the location of the tumor. In this age group the operation appears to pose a greater risk than the presence of an asymptomatic tumor.

Spontaneous osteonecrosis of the knee: biochemical markers of bone turnover and pathohistology

OBJECTIVE

The aim of this study was to evaluate bone metabolism in patients with spontaneous osteonecrosis (ON) of the medial femoral condyle.

METHOD

In 22 consecutive patients, undergoing total knee arthroplasty, biochemical markers of bone metabolism were measured in aspirates from cancellous bone and in samples obtained simultaneously from peripheral blood. Specimens of the medial femoral condyle were available for histologic examination and the lesion size, assessed on radiographs, was compared with the results from bone turnover measurements. Twenty patients with osteoarthritis (OA) of the knee served as a control. Bone-specific alkaline phosphatase (bone ALP), osteocalcin (OC), procollagen type I N-terminal propeptide (PINP), and C-terminal cross-linking telopeptide (ICTP) were studied.

RESULTS

Mean serum levels of analytes were not different in patients with ON and OA. The serum concentrations averaged 16.2 vs 13.3 ng/mL (OC), 10.2 vs 12.1 ng/mL (bone ALP), 4.6 vs 4.1 ng/mL (ICTP), and 33.2 vs 40.4 ng/mL (PINP) in patients with ON and OA, respectively. In samples obtained from cancellous bone, mean concentrations of all markers were elevated significantly when compared to serum levels. The mean marker concentrations in samples obtained from cancellous bone were 33.8 vs 43.3 ng/mL (OC), 34.6 vs 37.3 ng/mL (bone ALP), 64.8 vs 36.1 ng/mL (ICTP, P=0.02), and 208.0 vs 176.2 ng/mL (PINP) in patients with ON and OA, respectively. The lesion size was at mean 440.5+/-275.8mm(2) in knees with ON and did not correlate with either serum or bone concentrations of all markers tested (P>0.1).

CONCLUSION

The marked elevation of markers in samples obtained from cancellous bone pointed at increased turnover in both diseases when compared to healthy individuals. In line with histologic findings of necrosis of subchondral bone, focal degradation of collagen type I was more pronounced in knees with ON. Mean serum concentrations of all markers, however, were not different from healthy individuals and thus did not provide any useful clue in the diagnosis spontaneous ON.

The importance of delayed images in gastrointestinal bleeding scintigraphy

Although radionuclide methods for the detection of gastrointestinal (GI) bleeding have been available for more than 20 years, the value of delayed images in GI bleeding scintigraphy is still regarded controversially. The aim of this study was to determine the value of delayed images in a group of patients with predominantly low-grade intermittent bleeding. Eighty-nine consecutive GI bleeding scintigraphies of 75 patients were analysed retrospectively. All patients were referred to our department after other diagnostic methods had failed to identify the localization of GI bleeding. After the dynamic study, delayed images were acquired for up to 24 h until a bleeding site was identified. Data on the clinical outcome were available in all but five patients. No patient with a negative scan died from GI bleeding. A positive result was found in 41 patients (55%). The scans of 11 of these 41 patients (27%) became positive during dynamic imaging. Four required immediate surgery and, in another patient, surgery was not performed because of diffuse bleeding of the entire GI tract. One patient died without surgical intervention. Thirty-three scans of 30 of these 41 patients (73%) were positive on delayed imaging only, leading to surgery in 12 individuals. Our findings demonstrate the importance of delayed images in GI bleeding scintigraphy. Many of our patients who required surgery had scans that did not become positive for several hours.

Effects of irradiation on 99m Tc sestamibi and 201Tl uptake in a human papillary thyroid carcinoma cell line

Both 99mTc sestamibi and 201Tl have been used in conjunction with 131I scintigraphy for follow-up of patients with thyroid cancer. The aim of the study was to determine if irradiation affects tracer uptake in papillary thyroid cancer cells. The human papillary carcinoma cell line (PAP/ES-1) used in this study was generated from a papillary thyroid tumour obtained after surgery. For the in vitro uptake studies cells were seeded at 2 x 105 cells/well into 12-well microtitre plates. Irradiation was performed with a 60Co source (total dose, 2 Gy and 10 Gy). After incubation at 37 degrees C the supernatants were saved for determination of the unincorporated activity. The reaction was stopped by washing the cells four times in ice cold phosphate buffered saline. Total cellular uptake was determined by measuring cell lysate radioactivity in a Compugammasystem and was expressed as per cent uptake per mg of total cellular protein. At continuous incubation 201Tl uptake was significantly (P<0.01) higher after radiation whereas no effect of irradiation was found on 99mTc sestamibi uptake. Pulsed experiments revealed that irradiated cells displayed a faster 201Tl efflux. The net tracer retention at 90 min was similar to 201Tl to that of 99mTc sestamibi. We conclude that 99mTc sestamibi kinetics in thyroid cancer are not affected by irradiation and may therefore be superior to 201Tl in the follow-up of thyroid cancer shortly after radiotherapy.

Does motion analysis in postexercise gated sestamibi SPECT reflect rest left ventricular motion even in severe coronary artery disease?

PURPOSE

Evidence has suggested that postexercise gated Tc-99m sestamibi SPECT (GSPECT) provides combined information about resting wall motion and exercise perfusion. No data have been published about possible differences in wall motion analysis between postexercise and resting GSPECT.

METHODS

Fifty patients underwent postexercise (symptom-limited bicycle stress) and rest GSPECT and cardiac catheterization with contrast ventriculography. In 35 patients, additional rest planar Tc-99m RBC radionuclide ventriculography (RNV) was performed. Four observers independently performed left ventricular ejection fraction (LVEF) calculations and visual analysis of regional wall motion (graded in four stages) for all studies.

RESULTS

The LVEF calculations in GSPECT revealed a statistically significant difference between postexercise (45.8 +/- 15.7%) and rest (48.0 +/- 16.1%; P < 0.05) determination. Postrest GSPECT LVEF showed a better correlation with LVEF determination performed with contrast ventriculography and RNV than did postexercise GSPECT LVEF. The reduced postexercise wall motion could be shown in segments with exercise-induced ischemia and in those with normal regional perfusion but not in segments with irreversibly abnormal perfusion.

CONCLUSIONS

Postexercise GSPECT provides reliable information regarding global wall motion even in severe coronary artery disease, but regional wall motion is underestimated compared with rest GSPECT, because of an imprecise surface detection algorithm in ischemic wall segments and possibly postexercise stunning in severe coronary artery disease.

Splenosis mimicking tumor recurrence in renal cell carcinoma: detection on selective spleen scintigraphy

A 2-year-old boy had been operated on for a giant renal cell carcinoma including splenectomy because of disrupture of the splenic capsule. During a follow-up examination, 3 nodules were detected by ultrasound in the splenorenal area. This gave reason to suspect tumor recurrence. Considering the possibility of splenosis, a selective spleen scan using denatured red blood cells was performed as a final diagnostic step. This method confirmed the nodules as representing splenic tissue. Splenosis should be included in the differential diagnosis of solid masses in the postsplenectomy patient.

FDG positron emission tomographic, radioiodine, and MIBI imaging in a patient with poorly differentiated insular thyroid carcinoma

Poorly differentiated insular thyroid carcinoma is now classified as a separate entity among other tumors of the thyroid gland. Its histologic pattern and its clinical course are regarded as intermediate between well differentiated and anaplastic thyroid cancer. Insular carcinoma accumulates I-131, but no data exist regarding its fluorodeoxyglucose (FDG) positron emission tomographic (PET) uptake. The authors report F-18 FDG PET, Tc-99m MIBI, and radioiodine imaging features in a 63-year-old patient with metastatic insular thyroid carcinoma. After total thyroidectomy (for poorly differentiated insular carcinoma pT3a), the patient was referred for radioiodine ablation. No signs of recurrence were present until 16 months later, when thyroglobulin levels increased. An I-131 scan showed a single lesion in the right lung, and further radioiodine treatment was administered (cumulative dose [530 mCi], 19,610 MBq I-131). Three years after the initial diagnosis, FDG-PET and Tc-99m MIBI scans were performed within 5 days during thyroxine treatment. After that, thyroxine substitution was withdrawn; 6 weeks later, an I-131 whole-body scan was performed. Both radioiodine and MIBI images showed increased tracer uptake in the known lung lesion. However, FDG PET showed a normal tracer distribution. Magnetic resonance and computed tomographic imaging confirmed a 12-mm lesion in the right upper lobe. These findings support the concept of the "flip-flop phenomenon" in insular thyroid carcinoma, an alternating pattern of metastases with either I-131 or FDG-uptake. Despite poorly differentiated histologic findings, glucose metabolism was not increased in this patient with an insular tumor.

Does (99m)Tc-Sestamibi in high-grade malignant brain tumors reflect blood-brain barrier damage only?

(99m)Tc-Sestamibi (MIBI) has been successfully applied in recurrent glioblastoma. The aim of this study was to evaluate the incremental diagnostic information of MIBI as a tumor-avid radiopharmaceutical compared with (99m)Tc-pertechnetate ((99m)Tc) as sole indicator of the integrity of the blood-brain barrier. Twenty-five patients with confirmed recurrent brain tumors were included. MIBI SPET was performed 10 min after injection of 555 MBq MIBI intravenously with a triple-headed gamma camera equipped with LE-UHR-PAR collimators over 360 degrees (3 degrees /step) and stored in a 128(2) matrix. Identical acquisition parameters were used for (99m)Tc SPET, which was acquired 3 h after injection of 740 MBq (99m)Tc. Normalized tumor uptake (NU) was calculated from attenuation-corrected transaxial slices. In addition, tumor/plexus, tumor/nasopharynx, and tumor/parotid gland ratios were assessed in both studies. No statistically significant differences were detected for the mean NU of tumor tissue with MIBI (0.26 +/- 0.10) and (99m)Tc (0.39 +/- 0. 33) and for the tumor/nasopharynx and tumor/parotid gland ratios; only the tumor/plexus ratio was significantly higher for (99m)Tc than for MIBI (p < 0.05). In conclusion, our data indicate that MIBI scintigraphy in brain tumors at 10 min postinjection reveals no additional visual information over that provided by the conventional (99m)Tc-pertechnetate brain scan, and in addition, tracer retention reflects primarily blood-brain barrier damage.

ROC analysis of three perfusion display options for ECG-gated perfusion SPECT in severe CAD

AIM

The simultaneous computation and display of wall motion and perfusion patterns in a single 3D ventricular model would considerably ease the assessment of ECG-gated Tc-99m-sestamibi SPECT, yet the effect on the accuracy of allocating regional perfusion has so far not been validated.

METHODS

3D perfusion mapping (3D Perfusion/Motion Map Software) was compared to the visual assessment of ungated tomographic slices and polar perfusion mapping (Cedars-Sinai PTQ) by correlation analysis and receiver operating characteristics (ROC) analysis at different cut-off levels for coronary stenoses in 50 patients (11 single-, 22 two-, 16 three-vessel disease). Ungated SPECT data were obtained by adding the intervals prior to reconstruction and displaying conventional tomographic slices. All display options were visually assessed in 8 ventricular segments according to a 4-point scoring system and compared to the graded results of coronary angiography.

RESULTS

All three display options showed a comparable diagnostic performance for the detection of severe stenoses. The diagnostic gain for the detection of stenoses above 59% was highest for ungated tomographic slices, followed by ungated polar mapping and 3D mapping. Regional assessment revealed a limited performance of 3D mapping in the proximal anterior and distal lateral wall. Polar mapping showed a balanced regional performance.

CONCLUSION

3D Perfusion mapping provides comparable information to conventional display options with the highest diagnostic strength in severe stenoses. Further improvement of the algorithm is needed in the definition of the valve plane.

Scintigraphic assessment of pulmonary and whole-body blood flow patterns after surgical intervention in congenital heart disease

Glenn shunt and Fontan procedure, the most widely used surgical procedures in congenital heart anomalies, may be associated with abnormal pulmonary blood flow patterns and the development of pulmonary arteriovenous fistulae.

METHODS

This study quantified pulmonary and whole-body blood flow using the microsphere technique by sequential injection of 99mTc microspheres into upper and lower limb veins and performing planar lung imaging in four projections and anterior and posterior whole-body scans in 46 patients with either Glenn shunt or Fontan procedure. The right-to-left shunt volume was estimated by a brain and kidneys-to-lungs ratio and compared with calculations from the whole-body scans.

RESULTS

In 31 of 46 patients, the blood from the superior vena cava was drained preferentially into the right lung (75%+/-19%). The inferior venous system was drained equally into both lungs. The right-to-left shunt volume was 24%+/-12% after injection into the superior caval system, 50%+/-18% after injection into the inferior caval system. A subgroup of patients who had undergone a palliative Blalock-Taussig shunt (BTS) before the final surgery showed a perfusion pattern that was not known after pulmonary angiography or contrast echocardiography: 15 of 24 patients with BTS had hypoperfusion of the upper lobe on the side of the BTS after injection into the arm vein and corresponding normal perfusion or hyperperfusion when injected into the foot vein.

CONCLUSION

Lung perfusion scintigraphy after tracer application into the superior and inferior caval systems detects more abnormal pulmonary blood flow patterns than contrast echocardiography and is the only procedure able to quantify right-to-left shunt volume individually for the superior and inferior caval systems. Thus, this diagnostic technique should be part of the routine follow-up in children after Glenn shunt or Fontan procedure.

Acupuncture in the treatment of posttraumatic pain syndrome

To test the hypothesis that classical Chinese acupuncture provides an additional benefit subjectively as well as objectively in patients suffering from reflex sympathetic dystrophy, a double-blind, placebo-controlled prospective trial was performed. Fourteen patients suffering clinically and scintigraphically from acute CRPS of the upper limb lasting of more than one but less than 6 months were studied. Patients were randomly assigned to either the classical acupuncture (group A) or sham acupuncture (group S), which was applied five times a week for three weeks and required 30 minutes. Both groups received the same defined standard treatment. The current state of pain was assessed by means of a visual analogue scale. Subjective success of treatment was rated by the patients by means of a rating scale. Each patient underwent a clinical examination and was investigated by 5-phase bone scan in order to confirm the diagnosis. The current state of pain as well as clinical parameters were almost identical in patients of group A and of group S at the beginning. During therapy clinical parameters as well as pain improved in both groups and reached nearly normal levels after 6 months. Owing to the small number of patients in our study, no differences between sham and treatment group could be recognized. For a definitive statement the treatment of further patients in both groups is planned. Determinations of the effect of acupuncture on clinical parameters, based on long-term follow-ups are projected.

Anemia and carnitine supplementation in hemodialyzed patients

Carnitine supplementation in hemodialyzed patients was studied in a double-blinded, randomized, controlled trial in order to elucidate the effect of intravenous carnitine on renal anemia in patients treated with recombinant human erythropoietin (rHuEPO). Twenty stable hemodialysis (HD) patients received intravenous L-carnitine after each dialysis session in a dosage of 5 (N = 15) and 25 (N = 5) mg/kg, respectively, together with intravenous iron saccharate (20 mg/HD session) for four months and without iron for a further four months. Twenty patients received placebo instead of carnitine with an identical iron regimen. After a run-in phase of six months with a stable rHuEPO requirement, the rHuEPO dose was adjusted monthly when necessary to maintain target hemoglobin levels. At study entry (T0), plasma and red blood cell carnitine levels did not correlate significantly with the rHuEPO requirement. However, plasma free and total carnitine levels showed a significant negative correlation with erythrocyte survival time at T0. After four months of coadministration of intravenous iron and L-carnitine (T4), the rHuEPO requirement decreased in 8 of 19 evaluable HD patients. In these responders, the weekly rHuEPO dose was decreased significantly by 36.9+/-23.3% (183.7+/-131.7 at T0 vs. 126.6+/-127.9 U/kg/week at T4, P < 0.001). The rHuEPO requirement, however, was unchanged when all carnitine-treated patients were compared between T0 and T4 (T0: 172.0+/-118.0 vs. T4: 152.3+/-118.8 U/kg/week, P = 0.07, NS), but the erythropoietin resistance index decreased significantly in this group (T0: 16.0+/-11.0 vs. T4: 13.6+/-10.5 U/kg/week/g of hemoglobin, P < 0.02). The erythrocyte survival time was measured in five HD patients treated with iron and carnitine at T0 and T4. Two out of these patients were carnitine responders and showed an increase of erythrocyte survival time of 15 and 20%, respectively. After the withdrawal of iron supplementation, the rHuEPO requirement increased comparably in both L-carnitine- and placebo-treated patients during four more months. According to our data, L-carnitine, in addition to iron supplementation, may have an effect on erythropoietin resistance and erythrocyte survival time in HD patients. More than half of our patients, however, showed no benefit. Further studies to identify those HD patients who might have a benefit of carnitine supplementation, as well as studies concerning the optimal dosage, duration, and way of administration of carnitine supplementation and its mechanism of action, are required.

An artificial neural net and error backpropagation to reconstruct single photon emission computerized tomography data

At present, algorithms used in nuclear medicine to reconstruct single photon emission computerized tomography (SPECT) data are usually based on one of two principles: filtered backprojection and iterative methods. In this paper a different algorithm, applying an artificial neural network (multilayer perception) and error backpropagation as training method are used to reconstruct transaxial slices from SPECT data. The algorithm was implemented on an Elscint XPERT workstation (i486, 50 MHz), used as a routine digital image processing tool in our departments. Reconstruction time for a 64 x 64 matrix is approximately 45 s/transaxial slice. The algorithm has been validated by a mathematical model and tested on heart and Jaszczak phantoms. Phantom studies and very first clinical results ((111)In octreotide SPECT, 99mTc MDP bone SPECT) show in comparison with filtered backprojection an enhancement in image quality.

Is there a diagnostic role for bone scanning of patients with a high pretest probability for metastatic renal cell carcinoma?

BACKGROUND

The utility of performing whole-body bone scintigraphy (BS) as part of a routine staging workup for patients with renal cell carcinoma (RCC) is currently being debated. This study investigated the diagnostic performance of BS in 36 patients with a high pretest probability for bone metastases due to abnormal laboratory tests, pain, or confirmed nonosseous metastases.

METHODS

Planar whole-body BS was performed in all patients 3 hours after the intravenous injection of 555 MBq (15 mCi) of technetium-99m-3,3-diphosphono-1,2-propane dicarboxylic acid tetrasodium salt).

RESULTS

In 14 of 36 patients, bone metastases could be confirmed either due to computed tomography or magnetic resonance imaging (n=11) or open site directed biopsy (n=3), respectively. The sensitivity ranged from 10% to 60%, depending on the applied visual threshold. The extent of the metastatic involvement was underestimated in all cases. No diagnostic pattern of tracer accumulation, clinical features, or laboratory tests was identified as enhancing the sensitivity for the detection of bone metastases in this population.

CONCLUSIONS

The authors concluded that, even among preselected patients, BS has no diagnostic role in RCC and should therefore be omitted from the clinical workup.

ROC Analysis of Three Perfusion Display Options for ECG-gated Perfusion SPECT in Severe CAD

Aim: The simultaneous computation and display of wall motion and perfusion patterns in a single 3D ventricular model would considerably ease the assessment of ECG-gated Tc-99m-sestamibi SPECT, yet the effect on the accuracy of allocating regional perfusion has so far not been validated. Methods: 3D perfusion mapping (3D Perfusion/Motion Map Software) was compared to the visual assessment of ungated tomographic slices and polar perfusion mapping (Cedars-Sinai PTQ) by correlation analysis and receiver operating characteristics (ROC) analysis at different cut-off levels for coronary stenoses in 50 patients (11 single-, 22 two-, 16 three-vessel disease). Ungated SPECT data were obtained by adding the intervals prior to reconstruction and displaying conventional tomographic slices. All display options were visually assessed in 8 ventricular segments according to a 4-point scoring system and compared to the graded results of coronary angiography. Results: All three display options showed a comparable diagnostic performance for the detection of severe stenoses. The diagnostic gain for the detection of stenoses above 59% was highest for ungated tomographic slices, followed by ungated polar mapping and 3D mapping. Regional assessment revealed a limited performance of 3D mapping in the proximal anterior and distal lateral wall. Polar mapping showed a balanced regional performance. Conclusion: 3D Perfusion mapping provides comparable information to conventional display options with the highest diagnostic strength in severe stenoses. Further improvement of the algorithm is needed in the definition of the valve plane.

Is early sestamibi imaging in head and neck cancer affected by MDR status, p53 expression, or cell proliferation?

A consensus has emerged that early imaging (within 20 min post-injection [p.i.] of sestamibi) has the highest diagnostic yield. Tc-99m-sestamibi uptake has been associated with P-glycoprotein-mediated multi-drug resistance (MDR), tumor vascularization, invasiveness, and cell proliferation. The aim of this study was to assess whether these parameters affect tumor uptake in current imaging protocols. Twenty-three patients with squamous cell carcinoma (SCC) of the mouth floor who were scheduled for surgery were imaged 5 min. p.i. with a triple-head gamma camera (360 degrees, 3 degrees/step SPECT, UHRPAR collimators). Tumor:nontumor tissue (TBR), tumor:gingiva (TGR), tumor:salivary gland (TSR), and tumor:nuchal muscle ratios (TNR) were calculated based on the cts/pix values of ROIs in the axial slices. The expression of the MDR gene was determined histochemically from biopsies. Cell proliferation was quantitated by the histochemical analysis of the Ki-67 protein (Ki-67 index); additionally, the p53 tumor suppressor gene (p53 index), a posttranslational stabilizer of the cell cycle at the G1 stage, was assessed. No significant differences were found for the uptake indices between MDR+ and MDR- tumors. Moreover, no significant correlation between sestamibi uptake and the Ki-67 and p53 indices could be demonstrated. The diagnostic information content of currently applied imaging protocols for sestamibi in SCC of the mouth floor is not affected by tumor-specific properties.

Technetium-99m-MIBI in primary and recurrent head and neck tumors: contribution of bone SPECT image fusion

We prospectively investigated 200 patients with the clinical suspicion for head and neck tumors. The final diagnoses were 94 primary and 56 (37 confirmed, 19 excluded) recurrent squamous cell carcinomas (SCCs), 3 primary and 7 (4 confirmed, 3 excluded) recurrent adenoid cystic carcinomas (ACCs), 6 non-Hodgkin's lymphomas, 10 distant metastases, 6 other malignancies, 10 inflammatory and 8 other nonmalignant conditions.

METHODS

Bone (600 MBq 99mTc-3,3-diphosphono-1,2-propane dicarboxylic acid tetrasodium salt) and hexakis-2-methoxyisobutyl isonitrile (MIBI) (600 MBq 99mTc-MIBI) SPECT were both performed under identical conditions (triple-head gamma camera; ultra-high-resolution, parallel-hole collimators; three-dimensional postfiltering) and judged independently and after superimposition. The results were compared to the results of biopsy, surgery and CT.

RESULTS

The overall sensitivity/specificity of MIBI was 90%/78% for tumor detection and 90%/95% for the identification of malignant lymph node involvement (CT: 79%/66%, respectively 90%/79%). In the subgroup of recurrent SCC and ACC the sensitivity/specificity for tumor detection was 95%/71% for MIBI versus 78%/68% for CT. The isolated assessment of bone SPECT had a sensitivity/specificity of 100%/17% for osseous tumor spread. Image fusion of MIBI and bone SPECT differentiated between regio-local bone involvement and inflammatory changes and increased the specificity of bone SPECT to 100% in primary staging. Tumor size, stage, histology and pretreatment had no statistically significant effect on tracer uptake or diagnostic utility of scintigraphy.

CONCLUSION

We propose the combined 99mTc-MIBI and bone ultra-high resolution SPECT as a highly useful imaging approach in the primary and secondary staging in patients with suspected malignancies in the head and neck region. The high specificity for malignancies in the head and neck region may be used in the differential diagnosis between head and neck malignancies and inflammatory disease in patients with the accidental finding of enlarged lymph nodes and no clinical signs of a primary tumor. Image fusion with bone scanning is mandatory for the topographical orientation and increases the specificity of bone scanning to differentiate between inflammatory or malignant causes of increased bone metabolism.

The usefulness of Tc-99m DMSA SPECT and three-dimensional surface rendering in an asymptomatic patient with a single kidney in the pelvis

The diagnostic problems in a clinically asymptomatic patient with a previously unknown ectopic single kidney in the pelvis and the diagnostic utility of three-dimensional surface rendering of Tc-99m DMSA SPECT for delineating ectopic functional renal parenchyma are reported. Inconclusive dynamic planar Tc-99m MAG3 renal scintigraphy was performed with the field of view centered at the upper abdomen. Twenty-four hours later, static planar Tc-99m DMSA scintigraphy 3 hours after injection delineated functional renal parenchyma only in the pelvis but did not reveal the shape of the organ. Three-dimensional surface rendering exposed a single ectopic kidney in the pelvis. This case is the first description of the advantages of three-dimensional surface rendering of Tc-99m SPECT in the diagnosis of an ectopic kidney.

Differential diagnosis of atypically located single or double hot spots in whole bone scanning

Our study assessed the predictive value of atypically located hot spots in routine 99mTc-DPD (3,3 diphosphono-1, 2-propane dicarboxylic acid tetrasodium salt) bone scanning for osseous tumor spread in patients with a history of malignant tumor.

METHODS

Of 1286 scans in consecutive patients with a history of malignant tumor, but with no current evidence of osseous tumor spread, 172 displayed one or two hot spots in the following locations: transverse process of a single vertebra, manubriosternal junction, unilateral process of L5/S1, unilateral shoulder, costal cartilage, single rib, and unilateral sternoclavicular joint. The final diagnosis could be established by a control bone scan after at least 6 mo, biopsy and/or postmortem, respectively, in 135 patients.

RESULTS

Of the atypical hot spots, 11.1% were the first indication for osseous tumor spread. This diagnosis was most probable for single hot spots in the rib (25%) and shoulder (21%). Conversely, hot spots in the sternoclavicular joint never indicated malignancy.

CONCLUSION

The likelihood of atypically located isolated hot spots indicating osseous tumor spread is higher than expected during routine investigations in patients with a history of malignant tumor but no current evidence for malignant disease. Only hot spots in the sternoclavicular joint did not indicate metastatic disease in our study.

Mandibular pain as the leading clinical symptom for metastatic disease: nine cases and review of the literature

BACKGROUND

Metastases to the jaws are a rare phenomenon. Nevertheless, the appearance of non-specific symptoms such as toothache can signal the onset of neoplastic disease in some patients.

PATIENTS

In this article, we present details of a 74-year-old patient with a history of breast cancer to illustrate this point. Retrospectively, covering a time span of one year, we could identify nine patients (1.2%) with metastatic disease to the mandible out of a total of 763 patients referred to our Maxillofacial Surgery department with non-specific jaw pain.

RESULTS

Four patients were subsequently diagnosed as having breast cancer, two had lung cancer, one prostate cancer, one renal cell carcinoma and one adenocarcinoma of unknown primary site. Only three of these patients had documented tumor spread to bones before the onset of jaw pain. In the other patients, the dental symptoms were either the first sign of a generalized neoplastic disease, or indicated relapse of disease after long term disease free interval. However, further work up disclosed generalized tumor spread with additional organ- or bone-lesions in all patients, and the median survival was only six months (range 3.5(-)+22) from diagnosis.

CONCLUSION

Pain of uncertain origin in the jaws should alert clinicians to the potential of metastatic disease in patients with a history of cancer and a bone scintigraphy should be done to rule out metastatic involvement. Although metastatic lesions in this area usually herald generalized neoplastic spread according to our experience, prompt diagnosis nevertheless can lead to useful palliation and an enhanced quality of life.

Diagnostic patterns for bone marrow oedema syndrome and avascular necrosis of the femoral head in dynamic bone scintigraphy

This study used logistic regression analysis to assess qualitative patterns of tracer accumulation in an attempt to improve the diagnostic utility of bone scintigraphy for the detection of the bone marrow oedema syndrome (BMOS) and avascular necrosis (AVN) of the femoral head. Forty-eight symptomatic patients aged 44 +/- 9 years (mean +/- S.D.) with a final diagnosis of AVN (n = 29 hips), BMOS (n = 22), nine other hip disorders or a normal hip were examined with dynamic bone scintigraphy and qualitatively assessed for 11 scintigraphic signs in four phases by three blinded investigators. The accuracy for a correct diagnosis based on individual experience was 60-61% for the three observers, even if different signs were emphasized. A cold spot in the femoral head in both blood pool phases and the bone phase was seen only in 24% of AVN hips. Diffuse tracer accumulation in the femoral head, neck and the intertrochanteric region in the blood pool phases was seen only in 36% of BMOS hips. The arterial phase and the finding of a normal acetabulum in the bone phase had no diagnostic utility in this study. The presence of uptake increased the accuracy of differentiating AVN and BMOS from other disorders or normal hips to 88%. AVN could be differentiated from BMOS with an accuracy of 86% if the signs of the femoral head and inter-trochanteric uptake were combined into a diagnostic pattern. The scintigraphic pattern described increases the diagnostic accuracy of planar dynamic bone scintigraphy for BMOS and AVN.

Clinical manifestations and diagnostic approach to metastatic cancer of the mandible

In a 12-month period, metastatic cancer was diagnosed in eight patients. Six of them presented with pain mimicking toothache, temporomandibular joint disorders or trigeminal neuralgia, while two showed osteopenic bone lesions in the panoramic radiography, and perimandibular swelling. Anesthesia of the lower lip was the only common clinical feature. In seven of the eight patients, a whole body bone scintigraphy and single photon emission computed tomography (SPECT) of the skull in combination with a whole body and SPECT anti-granulocyte (Tc-99m MAK 250/183) bone marrow scintigraphy was performed. One patient did not have combined scintigraphy performed secondary to severe systemic illness. In six of the seven, the results were conclusive for a metastatic bone lesion. Biopsies confirmed three patients to have a previously unrecognized primary cancer, one patient to have previously unrecognized recurrent cancer, and three patients to exhibit new metastatic spread of an already diagnosed cancer. Histology revealed breast, lung, renal cancer and a malignancy of inconclusive origin. In the remaining patient, combined scintigraphy suggested osteomyelitis, yet biopsy revealed a prostate cancer metastasis with acute inflammatory cell infiltration. Thus, the scintigraphy pattern of a hot spot in the bone scan and a cold lesion in the bone marrow scintigraphy is highly suggestive of a mandibular metastasis, if accompanied by anesthesia of the lower lip.

The diagnostic value of planar and SPET scintimammography in different age groups

Planar scintimammography (SMM) with 99Tcm-sestamibi (99Tcm-MIBI) has proved to be a useful method in the evaluation of breast lesions. The aim of our study was to determine the diagnostic value of planar and single photon emission tomograpic (SPET) SMM in different age group. We investigated women with breast lesions for which the surgeon recommended biopsy or careful follow-up. Seventy consecutive patients underwent supine planar SMM, while supine SPET was performed in 68 of the patients. Twenty-seven carcinomas in 23 patients and 35 benign lesions in 31 patients were confirmed histologically. In the remaining 16 patients, the findings were classified as benign at follow-up. The carcinomas and benign lesions had a mean (+/- S.D.) diameter of 25 +/- 17 and 17 +/- 11 mm respectively (P < 0.05). A sensitivity/specificity of 67/96% and 88/91% was obtained with the planar and SPET techniques respectively. The accuracy of both techniques was 90%. In patients aged 40 years or less, SPET increased the sensitivity from 50 to 100% (P < 0.01), whereas it decreased the specificity and accuracy from 94 to 81% and 91 to 81% respectively (N.S.). In patients aged 41-50 years, the sensitivity increased from 63 to 100% (P < 0.01), whereas there was a small decrease in specificity and an increase in accuracy (from 91 to 89% and 86 to 91% respectively, N.S.) We conclude that, in younger patients, a negative SPET SMM study indicates the need for careful follow-up rather than biopsy. However, the addition of SPET in supine scintimammography does-not change the overall accuracy significantly.

Comparison and histopathological correlation of three parathyroid imaging methods in a population with a high prevalence of concomitant thyroid diseases

The aim of this prospective study was to evaluate the diagnostic utility of a technetium-99m sestamibi dual-phase protocol enhanced by single-photon emission tomography (SPET) and semiquantitative analysis in comparison to established preoperative staging procedures in patients with primary hyperparathyroidism. Twenty-eight (50%) out of 56 patients had superimposed thyroid disease, and 12 patients had previously undergone neck surgery. Visual and semiquantitative analysis of planar 99mTc-sestamibi dual-phase imaging, SPET of the delayed phase, ultrasonography, and thallium-201 chloride-technetium-99m pertechnetate subtraction scintigraphy was further correlated with the histopathological examination of the surgical specimens. 99mTc-sestamibi dual-phase imaging achieved the highest sensitivity for side localization and precise localization compared with 201Tl-99mTc subtraction scintigraphy and ultrasonography, but the differences reached statistical significance only in comparison to ultrasonsography. Semiquantitative analysis did not enhance sensitivity. Adenoma detection by 99mTc-sestamibi dual-phase imaging was only correlated to serum calcium levels and osteocalcin, not to cell density or oxyphil cell count (SPET yielded additional information for the exact topographical localization of the parathyroid tumour in 22 (39%) patients with superimposed thyroid disease or previous neck surgery but did not enhance the overall detection rate.

Asystole during dipyridamole infusion in patients without coronary artery disease or beta-blocker therapy

The authors report two patients without coronary artery disease who experienced asystole during the IV infusion of dipyridamole on routine TI-201 myocardial perfusion imaging and review the literature for possible explanations of this rare side effect. Until now, this side effect was only reported in patients with coronary artery disease or beta-blocker therapy. Yet, the cases lacked both concomitant factors and autonomic dysregulation is suggested as a cause for asystole.

Differentiation of benign and malignant breast lesions: MR imaging versus Tc-99m sestamibi scintimammography

PURPOSE

To compare the accuracies of magnetic resonance (MR) imaging and scintimammography in differentiating benign from malignant breast lesions.

MATERIALS AND METHODS

MR imaging was performed in 66 women with 75 lesions during intravenous administration of gadopentetate dimeglumine. Planar and single photon emission computed tomographic (SPECT) scintimammography were performed (with 740 MBq technetium-99m sestamibi administered intravenously) in all 66 patients with 75 lesions and in 64 patients with 73 lesions, respectively. MR imaging and scintimammographic studies were independently evaluated by using signal intensity measurements versus time or focal tracer uptake to differentiate benign from malignant lesions. Histopathologic proof was obtained in 63 lesions. Twelve lesions were monitored with follow-up.

RESULTS

MR imaging was false-negative in one and false-positive in nine lesions. Planar scintimammography was false-negative in 10 and false-positive in six lesions. SPECT scintimammography was false-negative in four and false-positive in 10 lesions. Sensitivities and specificities for malignancy were, respectively, 96% and 82% for MR imaging, 62% and 88% for planar scintimammography, and 83% and 80% for SPECT scintimammography.

CONCLUSION

Both MR imaging and scintimammography are useful in the evaluation of breast cancer. MR imaging is more sensitive and as specific as scintimammography.

Creatine kinase-mb fraction and cardiac troponin T to diagnose acute myocardial infarction after cardiopulmonary resuscitation

OBJECTIVES

This study sought to evaluate the diagnostic value of the biochemical markers creatine kinase (CK), creatine kinase-MB fraction (CK-MB) and cardiac troponin T (cTNT) to diagnose acute myocardial infarction (AMI) after cardiopulmonary resuscitation (CPR).

BACKGROUND

Elevations of CK and CK-MB after CPR are a frequent finding and might be associated with ischemic myocardial injury, as well as physical trauma to the chest.

METHODS

Patients who had cardiac arrest and primary successful resuscitation were included in the study. The diagnosis of AMI was confirmed or ruled out by means of typical electrocardiographic findings, thallium-201 myocardial scintigraphy or autopsy, if death occurred during the hospital period, in 39 primary survivors of sudden cardiac death. In 24 patients (62%) the diagnosis of AMI was established. Serum cTNT, CK and CK-MB were measured, and the CK-MB/CK ratio was calculated on admission and after 12 h.

RESULTS

On admission all markers of myocardial injury proved to be weak methods for the diagnosis of AMI. After 12 h cTNT as well as CK-MB exhibited a similar diagnostic performance; CK and the CK-MB/CK ratio proved to be worthless. Sensitivity and specificity for a cTNT cutoff value of 0.6 ng/ml, 12 h after cardiac arrest, were 96% and 80%, respectively. For a CK-MB cutoff value of 26 U/liter, sensitivity was 96% and specificity was 73%.

CONCLUSIONS

Cardiac TNT and CK-MB are valuable tools in detecting AMI as the cause of sudden cardiac death. However, there is a considerable lack of sensitivity and specificity. Cardiac injury is probably caused not only by AMI, but also by myocardial damage related to CPR efforts.

[Nuclear medicine diagnosis of osteomyelitis]

Scintigraphic imaging identifies pathophysiological processes; in other words it assesses regional perfusion, permeability, leukocytic accumulation and bone turnover. These processes precede morphological changes and this accounts for the high sensitivity of nuclear medicine procedures as well as the low specificity for the differential diagnosis of different diseases with similar pathophysiological characteristics. This review (1) describes and evaluates the currently used scintigraphic procedures, (2) suggests their differential use in certain clinical settings in comparison with alternative radiological methods and (3) addresses new developments in diagnosis using nuclear medicine procedures. In summary, we advise dynamic bone scanning as a primary scintigraphic investigation. A negative scan excludes osteomyelitis in most cases. The comparison is made with conventional radiology and clinical history. In cases with short clinical histories (= granulocytic inflammation), leukocyte scintigraphy should be the next diagnostic step; in chronic processes (lymphomonocytic inflammation), gallium scintigraphy is advisable. Other scintigraphic methods might be of additional use in experienced hands. SPECT is useful for clarifying inconclusive planar scans of the head, spine and large joints.

Utility of technetium-99m-sestamibi to assess osseous tumor spread

We report the staging results and the surgical outcome of a male patient with squamous-cell carcinoma in the floor of the mouth and a bone SPECT scan suggestive of local tumor infiltration of the mandible. Additional 99mTc-sestamibi SPECT imaging of the primary tumor and superimposing of both studies excluded osseous tumor spread and less extensive surgery was performed. Pathohistological examination confirmed the scintigraphic results and indicated a nonspecific periostal reaction as the cause of the positive bone scan. Nevertheless, a high-resolution camera and careful superimposition of both studies is mandatory if the differential diagnosis of an osseous tumor spread of a malignant tumor in the floor of the mouth and possibly less extensive surgery is at stake.

Bone metastasis with superimposed osteomyelitis in prostate cancer

The following case of a male patient with a history of prostate cancer suffering from pain and swelling in the right mandibular area illustrates the well-known diagnostic problem of a superinfected tumor. Orthopan tomography and CT showed no defects in bone structure or smooth tissue. Whole-body bone scanning showed increased tracer uptake in the mandibular bone and in several other locations in the skeletal system. Antigranulocyte immunoscintigraphy showed increased uptake over the right mandible, whereas the other metastatic sites were visualized as cold spots. A second CT scan depicted a sclerotic lesion with surrounding periostal reaction and soft-tissue swelling and was interpreted as osteomyelitis. Therefore, clinical symptoms, bone scanning, antigranulocyte immunoscintigraphy and follow-up CT resulted in a diagnosis of osteomyelitis, although open needle biopsy revealed the lesion to be prostate cancer metastasis with massive leukocytic invasion.

Five phase bone scintigraphy supports the pathophysiological concept of a subclinical inflammatory process in reflex sympathetic dystrophy

This study evaluates quantitative and qualitative patterns of bone scintigraphy and correlates them to laboratory findings and clinical signs to reveal possible inflammatory reactions in RSD. Activity ratios between the affected hand/foot and the contralateral side were calculated in 99mTc DPD-bone scintigraphy for five phases (arterial: 0-30 sec, early blood pool: 0.5-5 min. late blood pool: 5-15 min, 3 hrs early bone, 24 hrs late bone phase) and the presence of five scintigraphic signs in the bone phases was assessed. Activity ratios of all phases correlated with ESR those in the early and late bone phase correlated with alpha 2 globulin and beta globulin concentrations and those in the arterial, the early and late blood pool phase with the gamma globulin concentrations, respectively. Clinical features such as pain, swelling, physical force, temperature differences and the duration of symptoms did not correlate to the activity ratios. However, three signs in the bone phase were negatively correlated to albumin concentrations. Positive correlations were found for alpha 2, gamma globulin concentrations, ESR, neutrophil cell counts and individual uptake patterns. We conclude that the quantitative analysis of five phase bone scintigraphy in RSD reveals different aspects of tracer kinetics and provides different pathophysiological information. Lateralization of regional hyperemia, increased micro vascular permeability and bone metabolism in RSD parallels shifts in protein concentrations and blood cell counts that are suggestive of a subacute inflammatory process, even in patients with no overt signs of inflammation.

Pattern recognition in five-phase bone scintigraphy: diagnostic patterns of reflex sympathetic dystrophy in adults

The objective of this study was to assess qualitative and quantitative patterns of tracer accumulation to increase the diagnostic utility of bone scintigraphy in reflex sympathetic dystrophy (RSD). Of 120 patients with high clinical suspicion for RSD, 96 were confirmed as having RSD during follow-up, while the remaining 24 were used as controls. Clinical parameters were measured and correlated to five activity ratios (0-30 s, 0.5-5 min, 5-15 min, 3 h, 24 h) and five scintigraphic signs. Monitoring three dynamic phases revealed different tracer kinetics of potential diagnostic utility; however, the 24-h bone phase offered no additional diagnostic contribution and can be omitted. Quantification provided objective parameters for the duration of symptoms, pain and impairment of movement but not for surface temperature differences, swelling and impairment of physical force. It is of limited use for diagnosis except for the exclusion of disease. Discriminant analysis revealed the combination of three signs (diffuse uptake in carpus/tarsus+diffuse uptake in all small joints+increased activity ratio in the late blood pool phase) to be the pattern with the highest diagnostic accuracy independent of localisation, sex, age and precipitating factors. It is concluded that the scintigraphic confirmation of RSD is based on lateralisation in the late blood pool phase and the described pattern in the early bone phase.

Does dyspnoea during dipyridamole cardiac stress testing indicate bronchospasm and is the pretest clinical history predictive of this side-effect?

This study investigates the acute effects of intravenous dipyridamole (0.7mg/kg) on pulmonary airflow in relation to clinical parameters suggestive of chronic obstructive pulmonary disease (COPD) in order to assess predictive and causative factors of dyspnoea during cardiac stress testing. Mild pulmonary airflow obstruction was noted in all patients, but reached statistical significance only in small airways (FEF75-85%: -7%; P=0.034). The changes in pulmonary function parameters were independent of the clinical history. Dyspnoea under dipyridamole stress testing occurred in parallel with angina, yet was not associated with ischaemic or non-ischaemic left ventricular dysfunction. These data do not support the use of dipyridamole stress testing in asthmatics, but show that (1) the acute effects of a diagnostic dose of dipyridamole on pulmonary airflow are mild even in patients with a history suggestive of COPD and (2) dyspnoea during dipyridamole testing is not necessarily indicative of bronchospasm.

Parenchymal and nonparenchymal uptake of technetium-99m, indium-111, and iodine-125 low-density lipoprotein in the normal and estradiol-stimulated rat liver: tracer validation for quantitative low-density lipoprotein scintigraphy

This study quantifies the parenchymal and nonparenchymal uptake of technetium-99m (99mTc)- and indium-111 (111In)-low-density lipoprotein (LDL) in different states of hepatic LDL-receptor activity to validate quantitative LDL scintigraphy. Iodine-125 (125I)-LDL was used as reference tracer. Four Sprague-Dawley rats with 17-alpha-ethinyl estradiol (EE)-stimulated LDL-receptor activity and five controls received all three tracers simultaneously 90 minutes before collagenase liver perfusion and metrizamide gradient cell separation. Total liver uptake of 99mTc-, 111In-, and 125I-LDL was 1.8 +/- 1.0, 1.6 +/- 0.8, and 0.2 +/- 0.2% injected dose/g organ weight, respectively. The contribution of nonparenchymal cells to total hepatic tracer uptake was 5.4 +/- 4.7%, 11.6 +/- 10.3%, and 9.6 +/- 7.6% in controls. Estradiol treatment increased total liver uptake to 2.4 +/- 0.5, 2.0 +/- 0.2, and 0.5 +/- 0.3% injected dose/g and reduced nonparenchymal cell contribution to 2.3 +/- 2.6%, 4.2 +/- 4.8%, and 2.6 +/- 2.9%, respectively. Dual-isotope scintigraphy in EE-treated and control rats confirmed these data, with a lower total hepatic uptake of 111In-LDL in comparison with 99mTc-LDL but a comparative degree of increase by EE treatment. Both behave quantitatively comparable as residualizing tracers, yet 99mTc-LDL shows a higher affinity to the LDL receptor pathway of parenchymal cells. However, the nonspecific uptake of both tracers can be neglected for quantitative LDL scintigraphy, and external imaging of hepatic tracer uptake primarily reflects LDL-receptor activity of parenchymal cells.

Myocardial m-[123I]iodobenzylguanidine scintigraphy for the assessment of adrenergic cardiac innervation in patients with IDDM. Comparison with cardiovascular reflex tests and relationship to left ventricular function

Cardiac imaging using m-[123I]iodobenzylguanidine (mIBG) reflects sympathetic myocardial innervation. In patients with insulin-dependent diabetes mellitus (IDDM), the following were studied: 1) the prevalence of derangements of cardiac autonomic innervation as detected by mIBG scintigraphy in comparison with cardiovascular reflex tests and 2) the relationship between adrenergic cardiac innervation and left ventricular (LV) function. Twenty-four patients with IDDM without overt heart disease were studied after silent coronary artery disease was excluded by 201Tl scintigraphy. Cardiac innervation was evaluated by both mIBG scintigraphy (tomographic imaging) and cardiovascular reflex tests. Systolic (ejection fraction [EF] percentage) and diastolic (peak filling rate [PFR] defined as end-diastolic volumes per second [EDV/s]) LV function were determined by equilibrium radionuclide angiography at rest and during bicycle exercise. mIBG scintigraphy was also performed in 10 control subjects. All control subjects exhibited a normal myocardial mIBG distribution. Among diabetic patients, only six had normal mIBG scans (group 1), whereas 18 had evidence of regional adrenergic denervation (group 2). Reflex tests suggested cardiac autonomic neuropathy in only seven of these patients (P < 0.01 vs. mIBG). All patients had a normal EF at rest. However, group 2 showed an impaired response to exercise as indicated by a smaller increase in EF (5 +/- 6 vs. 13 +/- 5%, P < 0.05) and a lower PFR (5.9 +/- 0.8 vs. 7.3 +/- 1.2 EDV/s, P < 0.01). Myocardial mIBG scintigraphy reveals that in patients with IDDM, sympathetic myocardial dysinnervation is much more common than previously thought. Furthermore, subclinical LV dysfunction is related to derangements of adrenergic cardiac innervation.

Three-phase bone scintigraphy of hydroxyapatite ocular implants

Hydroxyapatite ocular implants are replicas of lamellar bone tissue derived from the exoskeleton of a reef-building coral by a hydrothermal chemical exchange reaction. Attached to the eye muscles, they act as a passive framework for fibrovascular ingrowth and can be drilled to hold the visible part of the artificial eye and allow synchronous eye movement. Fibrovascular ingrowth has to be confirmed by bone scintigraphy before the drilling procedure. This study monitored the vascular ingrowth into the implant in ten patients over 12 months to establish a clinically feasible imaging protocol. Tracer accumulation was monitored visually and quantitatively in dynamic and single-photon emission tomography (SPET) scans after the intravenous administration of 600 MBq of 99mTc-DPD. The implants showed no tracer accumulation in the arterial or blood pool phase. Accordingly, dynamic scintigraphy can be omitted from the imaging protocol. Delayed tracer accumulation appeared no earlier than 2 and no later than 6 months after surgery. Planar scintigraphy is not recommended as high-resolution SPET is necessary to separate the implant from the surrounding bone. We conclude that imaging can be confined to high-resolution SPET 3 h after tracer injection, no earlier than 3 months after surgery. The vascularized hydroxyapatite orbital implant is an important in vivo model for bone-seeking agents to study their uptake kinetics independently of any soft tissue and bone disease. Our results provide evidence that in normal bones the chemical absorption of 99mTc-DPD into the crystalline structure of hydroxyapatite is the only quantitatively relevant uptake mechanism.

Scintigraphic pitfalls in giant parathyroid glands

We report a case of hyperparathyroidism with surgically confirmed bilaterally enlarged parathyroid glands mimicking a normal thyroid gland. Technetium-99m-pertechnetate-201Tl chloride subtraction scintigraphy was inconclusive because of suppressed thyroidal [99mTc]pertechnetate uptake after coronary angiography. Technetium-99m-sestamibi double-phase scintigraphy showed homogeneous 99mTc-sestamibi uptake that mimicked a normal thyroid gland and no differential washout, thus leading to an erroneous visual interpretation of a normal scan. Semiquantitative assessment of tracer washout, however, can differentiate between normal thyroid tissue and symmetrical parathyroid uptake mimicking normal thyroid tissue. We conclude that semiquantitative assessment of tracer washout increases the diagnostic sensitivity of 99mTc-sestamibi double-phase scintigraphy if: (a) the interpreter is unaware of the anatomical situation, (b) the scintigraphic delineation of the thyroid is hampered by a blocked tracer uptake or (c) the visual interpretation reveals no differential washout in the neck region.