Clinical value of negative 68Ga-PSMA PET/CT in the management of biochemical recurrent prostate cancer patients

PURPOSE

To evaluate the clinical value of ⁶⁸Ga-PSMA PET/CT negativity in patients with biochemical recurrent prostate cancer (BCR).

METHODS

One hundred three BCR patients (median age, 70 years; median PSA, 0.47 ng/mL) with negative ⁶⁸Ga-PSMA PET/CT, followed up for at least 1 year, were retrospectively identified in a database of 1003 consecutive patients undergoing ⁶⁸Ga-PSMA PET/CT for BCR. Clinical recurrence (CR) was determined or excluded on follow-up imaging selected as per clinical practice. Clinical recurrence-free survival (CRFS) was computed from the date of negative ⁶⁸Ga-PSMA PET/CT to the date of evident disease; frequencies of CRFS were described as per ISUP patient subset (subset 1: ISUP grades 1 and 2; subset 2: ISUP grade 3; subset 3: ISUP grades 4 and 5) and other conventional variables.

RESULTS

In 57 patients out of 103 (55.3%), CR was detected in the prostatic fossa (45.6%), nodes (38.6%), and bone (15.8%). The median CRFS was 15.4 months (range, 12.1-20.5), with a CRFS at 12 months in 61.4% of cases (range, 50.9-70.4) whereas the 24-month CRFS was 34.8% (range, 24-45.8). ISUP subset 1 benefited from significantly longer CRFS compared to subset 2 and subset 3 (median CRFS, 20.5 months, 12.6 months, and 12.1 months, respectively). ISUP subset 3 had significantly poorer 24-month CRFS (9.3%) compared to subset 1 (47.8%) and subset 2 (33.5%). At the univariate and multivariate analyses, the ISUP subset was the only significant risk factor for clinical relapse; ISUP subset 3 and subset 2 patients held a higher risk of CR compared to subset 1 patients (HR of 2.75 [1.35-5.57] for subset 3 versus subset 1; HR of 2.08 [1.11-3.88] for subset 2 versus subset 1).

CONCLUSION

⁶⁸Ga-PSMA PET/CT negativity in early BCR patients (PSA < 0.5 ng/mL) with low-grade primary prostate cancer (ISUP1 and 2) may support the exploration of a clinical surveillance approach in future prospective studies.

Characterization of Laboratory Working Standard for Quality Control of Immunometric and Radiometric Estrogen Receptor Assays. Clinical Evaluation on Breast Cancer Biopsies

The objective of the study was to characterize a low-cost and reliable working standard material for quality control of estrogen receptor (ER) determination with dextran-coated charcoal (DCC) and enzyme immunoassay (EIA) methods. Human fibromatous uterine lyophilized cytosol demonstrated good characteristics of stability and applicability for this purpose. Eleven laboratories participated in the intralaboratory and interlaboratory quality control study, and they achieved slightly higher coefficients of variation for ER-EIA (interlaboratory, 37.7 %; intralaboratory, 22.9 %) than for ER-DCC (Interlaboratory, 24.2 %; intralaboratory, 15.7 %). There was an excellent correlation between ER results with ER-EIA and ER-DCC for 268 breast cancer biopsies. Quality assurance for ER assays using DCC techniques and immunometric methods with monoclonal antibodies (ER-EIA) can be set up with this available material of human origin to satisfy the characteristics of both techniques and the species specificity of monoclonal antibodies.

Breast Cancer Estrogen and Progesterone Receptors: Associations with Patients' Clinical and Epidemiologic Characteristics

A total of 1095 patients with operable breast cancer and en-rolled in a randomized clinical trial were analysed for estrogen (ER) and progesterone (PgR) receptor content of their primary tumor, and the relationships between steroid receptor status and several epidemiologic characteristics were studied. The proportion of ER+ and median ER levels increased with age: compared to women younger than 40, those aged 66 or more were approximately three times more likely to have an ER+ tumor (OR = 3.0, 95% C.I. = 1.6–5.7). This difference tended to be more marked after comparison between patients with ER > 100 fmol/mg protein and ER- within the same age groups: OR = 7.04, 95 % C.I. = 2.89–17.12. No association emerged between age and PgR. ER status and concentrations were independent of menopausal status after adjustment for age, whereas the proportion of PgR+ and PgR levels were significantly lower in postmenopausal patients of the same age. The distribution of ER and PgR profiles was similar in relation to family history of breast cancer, reproductive events and other selected epidemiologic characteristics of the patients.

Sister Chromatid Exchanges in Cultured Amniocytes Exposed to Diagnostic Ultrasound in Vitro

An in vitro system has been set up to study the possible genetic effects of diagnostic ultrasound (US) on the developing fetus. Amniotic cells were cultured by the in situ technique. Well established clones were exposed to US for various lengths of time using a linear array transducer within a sound transparent apparatus. Cells were then grown in the presence of 5-bromo-2'-deoxyuridine and processed for scoring the number of sister chromatid exchanges (SCE) as the cytogenetic endpoint. There was no linear relationship between the SCE frequency and the duration of US exposure. Variance analysis showed that only interindividual variability was a significant component of total variation. Neither the main effect of treatment nor the interaction effect were statistically significant. The data suggest that US delivered from a diagnostic unit to actively growing cultured fetal cells in a system closely mimicking the conditions of US exposure during amniocentesis does not induce SCE.

Rehabilitation and surgical management of ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disease which, if untreated, may progress to severe damage of the spine with functional impairment, disability and poor quality of life. An increased mortality has been reported in AS patients compared to the general population. AS requires combined management (pharmacological and non-pharmacological) and advice by different health professionals. Even the pharmacological treatment in the last decade has dramatically changed the outcome, the severity of the disease might require a surgical approach for the hip involvement with total hip replacement, or the corrective spinal surgery. However, this surgery deserves some careful approaches since the complexity of the disease. Rehabilitation still represents a cornerstone of the global management of AS patients. The present review summarizes the state of art of surgical management of these two diseases.

Femoroacetabular impingement: role of imaging

The femoroacetabular impingement (FAI) is an impingement characterized by repetitive abutment between the femur and the acetabular rim during hip motion due to loss of joint clearance (Imam and Khanduja in Int Orthop 35(10):1427-1435, 2011; James et al. in AJR Am J Roentgenol 187(6):1412-1419, 2006). Femoroacetabular impingement (FAI) can be classified as either cam or pincer type, and it can be differentiated on the basis of a predominance of either a femoral or an acetabular abnormality (Pfirrmann et al. in Radiology 244(2):626, 2007; Ganz et al. in Clin Orthop Relat Res 466(2):264-272, 2008). In cases of cam FAI, the nonspherical shape of the femoral head at the femoral head-neck junction and reduced depth of the femoral waist lead to abutment of the femoral head-neck junction against the acetabular rim. In cases of pincer FAI, acetabular overcoverage limits the range of motion and leads to a conflict between the acetabulum and the femur. The most important role of preoperative MR evaluation in patients affected by FAI is the accurate assessment of the damage's extension.

Gastrointestinal perforation: ultrasonographic diagnosis

Gastrointestinal tract perforations can occur for various causes such as peptic ulcer, inflammatory disease, blunt or penetrating trauma, iatrogenic factors, foreign body or a neoplasm that require an early recognition and, often, a surgical treatment.Ultrasonography could be useful as an initial diagnostic test to determine, in various cases the presence and, sometimes, the cause of the pneumoperitoneum.The main sonographic sign of perforation is free intraperitoneal air, resulting in an increased echogenicity of a peritoneal stripe associated with multiple reflection artifacts and characteristic comet-tail appearance.It is best detected using linear probes in the right upper quadrant between the anterior abdominal wall, in the prehepatic space.Direct sign of perforation may be detectable, particularly if they are associated with other sonographic abnormalities, called indirect signs, like thickened bowel loop and air bubbles in ascitic fluid or in a localized fluid collection, bowel or gallbladder thickened wall associated with decreased bowel motility or ileus.Neverthless, this exam has its own pitfalls. It is strongly operator-dependant; some machines have low-quality images that may not able to detect intraperitoneal free air; furthermore, some patients may be less cooperative to allow for scanning of different regions; sonography is also difficult in obese patients and with those having subcutaneous emphysema. Although CT has more accuracy in the detection of the site of perforation, ultrasound may be particularly useful also in patient groups where radiation burden should be limited notably children and pregnant women.

[Metastatic bone disease. Strategies for imaging]

Skeletal metastases represent the most common malignant bone tumor. They occur mainly in adults and even more frequently in the elderly. The most common metastases in men are from prostate cancer (60%) and in women from breast cancer (70%). Other primitive tumors responsible for bone metastases are: lung, kidney, thyroid, alimentary tract, bladder, and skin. The spine and pelvis are the most common metastatic sites, due to the presence of red (haematopoietic active) bone marrow in a high amount. As a general rule, the radiographic pattern was lytic type; other aspects were osteosclerotic, mixed, lytic vs mixed and osteosclerotic vs lytic patterns. The main symptom is pain, although many bone metastases are asymptomatic. The most severe consequences are pathologic fractures and cord compression. Clinical evaluation of patients with skeletal metastases needs multimodal diagnostic imaging, able to detect lesions, to assess their extension and localization, and eventually drive the biopsy (for histo-morphological diagnosis). These techniques give different performances in terms of sensitivity and specificity; but none of the modalities alone seems to be adequate to yield a reliable diagnostic outcome. Therefore multidisciplinary cooperation is required to optimize the screening, clinical management and follow-up of the patients. In other terms, what is the efficacy of these new diagnostic tests compared to the "older" diagnostic tests? Frequently the new procedures do not replace the older one, but it is added to the diagnostic workup, thereby increasing costs without impacting the "patient's condition". The aim of the present work is to propose an "algorithm" for the detection and diagnosis of skeletal metastases, which may be applied differently in symptomatic and asymptomatic oncologic patients. Bone scintigraphy remains the first choice technique in the evaluation of asymptomatic patients, in whom skeletal metastases are supposed. Although it has a high sensitivity, scintigraphy is unspecific. So that a negative scan response has to be re-evaluated with other methods: if clinical status remains "negative", the diagnostic route can stop. On the contrary, in patients with "positive" scan or with local symptoms and pain, the screening of metastatic lesions must be accomplished by a combination of radiography and CT: the result may be negative (for low sensitivity of conventional radiology), not conclusive (in this case bone biopsy is necessary) or symptoms are not due to metastatic lesions (i.e., osteoarthritis). CT represents an excellent mean of defining the extent of any metastatic lesions, especially those located at sites difficult to evaluate (vertebral column and pelvis). Before bone biopsy is carried out, MRI must be performed, because it is the only technique that makes it possible to distinguish between bone marrow components. It has been used most extensively in the evaluation of spine metastases. The limitation of MRI is the unspecificity of its findings, which may lead to an equivocal diagnosis, and because only part of the skeleton can be studied.

Air embolism: diagnosis with single-photon emission tomography and successful hyperbaric oxygen therapy

Venous air embolism may occur when the surgical field is above the level of the heart. We present a case of venous air embolism in a patient undergoing percutaneous nephrolithotripsy in the prone position and presenting with blindness and neurological deficits 8 h later. The clinical diagnosis of paradoxical air embolism was confirmed by early single-photon emission tomography (SPET), whereas magnetic resonance imaging including diffusion-weighted imaging (DW-MRI) was diagnostic only 30 h later. Hyperbaric oxygen therapy was successful. In this case, early DW-MRI scan was inconclusive, but a SPET study of the brain appeared to be useful in confirming the clinical diagnosis. Early hyperbaric oxygen was demonstrated to be a successful therapy.

A multicentre observational study of radionuclide therapy in patients with painful bone metastases of prostate cancer

A multicentre observational study was conducted by the Italian Association of Nuclear Medicine between 1996 and 1998. Twenty-nine Nuclear Medicine Departments participated. The aims of the study were to systematically evaluate the efficacy, toxicity and repeatability of radionuclide therapy of painful bone metastases (RTBM) in a large number of patients and to assess its incidence in patients with prostate cancer. Out of 818 treatments performed with a single i.v. dose of 148 MBq of strontium-89 chloride or 1,295 MBq of rhenium-186 hydroxyethylidene diphosphonate (HEDP), 610 could be evaluated (527 with 89Sr and 83 with 186Re-HEDP). Eighty-one patients received multiple (up to five) RTBM. The total number of retreatments was 100. Patients were followed up for a period of 3-24 months. Results, assessed according to pain relief and consumption of analgesic drugs, were expressed at four levels: 1, no response; 2, mild response; 3, good response; 4, excellent response. Responses were: level 1 in 19%, level 2 in 21.3%, level 3 in 33.3% and level 4 in 26.4% of cases. Retreatments showed significantly (P<0.01) worse responses (48% levels 3+4), in comparison to first RTBM. Duration of palliation was 5.0+/-3.5 months, and was longer in cases of excellent response, in first RTBM, in patients with limited metastases and when 89Sr was used. Better responses were found in cases of limited skeletal disease, under good clinical conditions, when life expectancy exceeded 3 months, and in radiologically osteoblastic or mixed bone lesions. The only statistically significant predictive factor was life expectancy (P<0.001). Flare phenomenon (14.1% of cases) did not correlate with the response. Haematological toxicity (mild to moderate in most cases) mainly affected platelets, and was observed in 25.5% of cases overall and in 38.9% of retreatments. RTBM did not seem to prolong life, though in some cases scintigraphic regression of bone metastases was observed. The two radiopharmaceuticals did not show any statistically significant differences in palliative efficacy and toxicity, either in first RTBM or in retreatments.

Radionuclide therapy for painful bone metastases. An Italian multicentre observational study. Writing Committee of an Ad Hoc Study Group

BACKGROUND

It has been affirmed that observational studies give analogous results to randomised controlled ones.

METHODS

A multicentre observational trial was conducted between 1996-1998 in order to evaluate the efficacy of palliative radionuclide therapy for bone metastases in a large number of patients. An evaluation was made on 510 patients with prostate cancer and painful bone metastases, treated with a single iv. dose of 89Sr-chloride (527 treatments) or 186Re-HEDP (83 treatments), in 29 Italian Nuclear Medicine Departments. Eighty-one patients received up to five injections, totalling 100 retreatments. Patients were followed up for a period of 3 months-2 years. Results were expressed at four levels of response: excellent, good, mild, and nil.

RESULTS

Responses were excellent in 26.4%, good in 33.3%, mild in 21.3% and nil in 19% of all treatments, while good and excellent responses were obtained in 48% of retreatments. No statistically significant correlations were found between response and age of patients, skeletal extension of tumour, pretherapeutic PSA levels, evidence of non-bony metastases, previous chemotherapy and/or external-beam radiotherapy; osteolytic lesions responded worse than osteoblastic or mixed ones. Hematological toxicity (mild to moderate), mainly affecting platelets, was observed in 25.5% of all treatments and in 38.9% of retreatments. No clear differences were found between the two radiopharmaceuticals employed.

CONCLUSIONS

Bearing in mind that observational studies can provide just as accurate results as randomised controlled trials, this study confirms the main findings of various limited monocentre trials.

[Diagnostic imaging of bone metastases]

PURPOSE

To present an "algorithm" for detection and diagnosis of skeletal metastases, which may be applied differently in symptomatic and asymptomatic cancer patients.

MATERIAL AND METHODS

February to March 1999 we randomly selected and retrospectively reviewed the clinical charts of 100 cancer patients (70 women and 30 men; mean age: 63 years, range: 55-87). All the patients had been staged according to TNM criteria and had undergone conventional radiography and bone scan; when findings were equivocal, CT and MRI had been performed too.

RESULTS

The primary lesions responsible for bone metastases were sited in the: breast (51 cases), colon (30 cases: 17 men and 13 women), lung (7 cases: 6 men and 1 woman), stomach (4 cases: 2 men and 2 women), skin (4 cases: 3 men and 1 woman), kidney (2 men), pleura (1 woman), and finally liver (1 men). The most frequent radiographic pattern was the lytic type (52%), followed by osteosclerotic, mixed, lytic vs. mixed and osteosclerotic vs lytic patterns. The patients were divided into two groups: group A patients were asymptomatic and group B patients had local symptoms and/or pain.

DISCUSSION

Skeletal metastases are the most common malignant bone tumors: the spine and the pelvis are the most frequent sites of metastasis, because of the presence of high amounts of red (hematopoietic active) bone marrow. Pain is the main symptom, even though many bone metastases are asymptomatic. Pathological fractures are the most severe consequences. With the algorithm for detection and diagnosis of skeletal metastases two different diagnostic courses are available for asymptomatic and symptomatic patients. Bone scintigraphy remains the technique of choice in asymptomatic patients in whom skeletal metastases are suspected. However this technique, though very sensitive, is poorly specific, and thus a negative bone scan finding is double-checked with another physical examination: if the findings remain negative, the diagnostic workup is over. On the contrary, in patients with a positive bone scan or with local symptoms and pain, radiography and CT are used for screening of metastatic lesions: results may be negative (for low sensitivity of conventional radiology) or questionable (in which case bone biopsy is necessary), or else symptoms may be due to different causes than metastatic lesions (i.e., osteoarthritis). Before bone biopsy is made, MRI must be performed, because it is the only technique that allows to distinguish between bone marrow components. The limitation of MRI is the poor specificity of its findings, which may provide misleading findings.

An uncommon case of fluid retention simulating a congestive heart failure after aspirin consumption

Nonsteroidal anti-inflammatory drugs are widely used and relatively safe medications. We report here an uncommon case of fluid retention simulating acute congestive heart failure, secondary to aspirin consumption, promptly reversible after discontinuation of therapy, and triggered again by pharmacological challenge test.

Underestimation of regional myocardial perfusion with Tc-99m sestamibi single-day rest-stress SPECT: a "drug washout" pitfall?

Myocardial perfusion scintigraphy with a Tc-99m sestamibi single-day SPECT protocol is a widely used technique to examine patients with possible or known coronary artery disease. A 76-year-old man with a clinical history suggestive of ischemic heart disease underwent Tc-99m sestamibi myocardial SPECT imaging with a same-day rest and stress protocol after temporary discontinuation of his current therapy, which included calcium channel and beta blockers and nitrates. The scintigraphic pattern was consistent with an asymptomatic infarction of the posterolateral myocardial wall and periinfarct ischemia. One week later, the patient had a Tc-99m sestamibi myocardial SPECT study at rest without discontinuing therapy, and scintigraphic images showed normalization of the posterolateral wall perfusion defect. The angiographic study showed a 90% stenosis of the circumflex artery. This case suggests that, during a 1-day cardiac SPECT protocol, washout of therapeutic pharmaceuticals may be responsible for underestimation of myocardial rest perfusion in territory supplied by a coronary artery with a critical stenosis.

New insights on flow-independent mechanisms of 99mTc-HMPAO retention in nervous tissue: in vitro study

SPECT using 99mTc-hexamethyl propyleneamine oxime (HMPAO) mainly reflects regional cerebral blood flow, however metabolic abnormalities also affect the retention of 99mTc-HMPAO.

METHODS

To rule out any flow factor, a test-tube model was used to evaluate the effects of metabolic alterations both on intracellular trapping of 99mTc-HMPAO and on extracellular glutamate and lactate dehydrogenase (LDH) outflow from rat brain slices.

RESULTS

Under control conditions, slices took up 7.0%+/-1.4% of 99mTc-HMPAO contained in the medium, whereas prelabeled slices released 10.8%+/-2.6% of their radioactive content; glutamate and LDH outflow were 49.1+/-21.6 pmol/mg protein/ min and 4.8+/-0.9 U/L/mg protein/min, respectively. The control medium was altered by adding a metabolic poison (5 mmol/L azide), removing glucose and replacing O2 with N2 to mimic ischemia (in vitro ischemia) and replacing Krebs solution with hypotonic medium to evoke cell lysis. Both azide and in vitro ischemia induced a significant increase in 99mTc-HMPAO release (15.8%+/-3.3% and 18.3%+/-6.2%, respectively), without any modification in LDH efflux. However, only azide reduced the uptake of the tracer. Conversely, glutamate outflow was massive during in vitro ischemia and was far lower during azide treatment. Under hypotonic medium conditions, the release of 99mTc-HMPAO, glutamate and LDH were dramatically increased. Surprisingly, a two-fold increase of 99mTc-HMPAO uptake was also found. When 1 mmol/L glutathione was added to the medium, to convert native lipophilic 99mTc-HMPAO into hydrophilic derivatives, tracer uptake was inhibited both under control and hypotonic medium conditions.

CONCLUSION

This study provides evidence that not only poisoning of the tissue but also in vitro ischemia induced a reduction of 99mTc-HMPAO retention. Moreover, we demonstrated that injuries causing cell membrane disruption led to hyperfixation of 99mTc-HMPAO.

Design and synthesis of a redox-active Tc-99m radiopharmaceutical with ferrocenedithiocarboxylate [FcCS = Fe(C5H4CS2)(C5H5)-]

The synthesis, at tracer level, of two Tc-99m complexes having the same chemical composition and structure, but differing by one electron in the total electron counting, is reported. These compounds have been prepared by reacting [99mTcO4]- with the piperidinium salt of the ligand ferrocenedithiocarboxylate {[Fe(II)(C5H4CS2)(C5H5)]- = FcCS}, in the presence of N-methyl S-methyldithiocarbazate as donor of N3-groups, and triphenylphosphine or SnCl2 as reducing agents. The formation of the neutral complex [99mTc(N)(FcCS)2] (compound A) and of the monocationic, mixed-valence complex [99mTc(N)(FcCS) (FcCS)]+ (compound B) {FcCS = [Fe(III)(C5H4CS2)(C5H5)]} was obtained in high yield. Both complexes comprise a terminal Tc triple bond N multiple bond and two FcCS ligands coordinated to the metal center through the two sulfur atoms of the -CS2 group, but they differ in the oxidation state of one of the two iron atoms of the coordinated FcCS ligands. In complex A, the two Fe atoms are both in the +2 oxidation state, while in B, one Fe atom is in the +2 and the other is in the +3 oxidation state. Thus, B is a mixed-valence Fe(II)-Fe(III) complex. B is easily converted into A by one-electron exchange with various reductants such as triphenylphosphine and excess SnCl2. Biodistribution studies in rats showed that complexes A and B are mostly retained in lungs and liver without any significant uptake in organs such as heart and brain.

Cerebral hypoperfusion detected by SPET in early neuro-Behçet syndrome

We used brain single-photon emission tomography (SPET) to detect hypoperfused areas in 15 consecutive Behçet syndrome patients. Five were suspected of having neuro-Behçet syndrome, having at least one neurological symptom. For these patients, SPET was performed within 1 month of the onset of nervous system involvement. The 15 patients fulfilled the criteria of the International Study Group for Behçet syndrome. Neurological assessment and SPET were complemented by EEG in all five patients with suspected neuro-Behçet syndrome and by magnetic resonance imaging in three. Brain SPET detected hypoperfused regions in all five neurological patients; EEG showed abnormalities in three. Magnetic resonance imaging was normal in the three patients in whom it was performed. SPET was negative in all patients without neurological involvement and 20 healthy controls. SPET detected a reduction in brain blood flow in early neuro-Behçet syndrome, but there was no definitive correlation between the hypoperfused brain regions and the clinical features. Further studies are required to evaluate the significance of brain hypoperfusion and the value of SPET in the early diagnosis of neuro-Behçet syndrome.

Labeling and biodistribution studies of Tc-99m radiopharmaceuticals with (o-hydroxyphenyl)diphenylphosphine

New Tc-99m radiopharmaceuticals with the ligand (o-hydroxyphenyl)diphenylphosphine have been prepared and their biodistributions evaluated in rats. The monoxo Tc(V) complex [99mTc(O)Cl(PO)2], the Tc(IV) complex [99mTc(OH)2(PO)2], the Tc(III) complex [99mTc(PO)3], and the nitrido Tc(V) complex [99mTc(N)(PO)2] have been characterized by TLC and HPLC chromatography, and their chemical structure elucidated by comparison with the corresponding complexes obtained using the beta-emitting isotope Tc-99g. Biodistribution studies of these complexes have been carried out in rats.

In vivo monitoring of bone-Pb and retrospective exposure: an assessment in occupationally exposed subjects

In this work we present the preliminary results of an investigation in to the bone burden of lead in occupationally exposed subjects. The assessment of bone lead levels normalised to the mineral content (mg/kg bone mineral) were carried out by means of an in vivo X ray fluorescence techniques (Pb-XRF). The measurements were performed on the second phalanx of the right index finger and the minimum detectable limits of the XRF techniques was estimated around 25-30 mg/kg. Although the blood lead level monitoring over long time seems to indicate working activities in environments with low sources of lead contamination, high Pb-XRF levels, and not well correlated with the exposure time, were found. These anomalous values could be explained in term of the dependence of zinc protoporphyrin assessment against the measurement time.

Technetium-99m sestamibi leg scintigraphy for non-invasive assessment of propionyl-L-carnitine induced changes in skeletal muscle metabolism

Carnitine derivatives, such as propionyl-l-carnitine (PLC), have been shown to improve walking distance in patients with obstructive peripheral artery disease (PAOD). The aim of this study was to ascertain whether technetium-99m sestamibi leg scintigraphy may be a useful tool in the evaluation of changes in skeletal muscle metabolism induced by chronic therapy with PLC. Twenty patients with clinical and instrumental evidence of PAOD were randomly assigned to a 3-month period of therapy with either PLC or placebo. Rest 99mTc-sestamibi leg scintigraphy and echo-Doppler sonography were performed on all subjects immediately before and upon completion of the treatment period. At the end of the protocol the following results were observed in patients who underwent PLC administration: (a) a significant increase in both thigh and calf 99mTc-sestamibi uptake, in comparison with baseline values (P<0.001); (b) the absence of statistically significant modifications of Doppler blood flow indices of the lower limbs. In conclusion, after chronic administration of PLC, a significant increment in skeletal muscle uptake of 99mTc-sestamibi was demonstrated without any apparent change in regional blood flow. This fact, if proven in further studies, may suggest a role for this tracer as a non-invasive probe of tissue bioenergetics.

Brain perfusion SPET and proton magnetic resonance spectroscopy in the evaluation of two systemic lupus erythematosus patients with mild neuropsychiatric manifestations

The diagnosis of central nervous system (CNS) involvement appears to be a major problem in systemic lupus erythematosus (SLE), especially when the clinical signs are non-specific or neuroimaging is unremarkable. Two SLE patients with mild neuropsychiatric manifestations were studied with magnetic resonance imaging (MRI), single photon emission tomography (SPET) and localized proton magnetic resonance spectroscopy (H-1 MRS). MRI was normal in both patients. SPET revealed areas of hypoperfusion in both patients. H-1 MRS demonstrated metabolic abnormalities in the regions corresponding to the hypoperfused areas. A correlation between H-1 MRS and SPET was noted: patients with mild neuropsychiatric SLE may have disturbances evident on SPET and H-1 MRS in the presence of normal anatomy on MRI, suggesting that CNS involvement in SLE has very strong physiological and neurometabolic components in individual patients.

How alternative are immunoassay systems employing non-radioisotopic labels? A comparative appraisal of their main analytical characteristics

The immunoassay is one of the most sensitive and reliable analytical techniques available in the clinical laboratory. The original label for immunoassays was radioisotopes, and these methods, radioimmunoassay (RIA) and immunoradiometric assay (IRMA) are still the reference methods, because of invulnerability of the radioactive emission with respect to environmental interference. Labels other than radioisotopes have been tested for use in immunoassay to improve the sensitivity and reliability and to avoid some of the disadvantages of radioisotopic techniques. New labels have continued to be developed (Horseradish peroxidase-HPR-, pyrophosphatase, luciferases, pyrodopirazines, europium cryptates, porphirins, phosphors) and new label detection methods have been set up (e.g. chemiluminescence assay, thermometric assay, NADP+ and FADP- based coupled assay). New immunoassay strategies such as simultaneous multianalyte automated test have been developed and the reliability of the assays has in some cases caused division among researchers about the choice between the radioisotopic immunoassay or the non-radioisotopic immunoassay, as considerable effort and investment had been devoted to the search for more sensitive and practicable tests than the classic RIA-IRMA methods. The evolution of immunoassays (Monoclonal Antibodies, non-radioactive tracers, automation) has produced systems which allow a large number of laboratories to determine a great number of analytes with very good practicability. The availability of fully automated systems has generated the opinion that analytical performance of immunoassays can be considered similar to that of many traditional parameters of clinical chemistry. This conclusion seems however too optimistic, in fact data collected from interlaboratory studies demonstrate that problems concerning the analytical reliability of the measurements still remain not completely solved. In the authors' opinion, this opposition between immunological assay based on isotopic or non-isotopic labels is misleading, because each assay (whether it uses isotopic, enzymatic, fluorimetric or luminescent labels) has its own analytical characteristics and performance. For this reason the term "alternative", used to indicate all non-isotopic assays as a unique class of tests, should be abandoned. From a theoretical point of view the choice should not be between isotopic and non isotopic techniques. For each analyte to be tested, it is advisable to use the immunological assay that suits the requirements of the laboratory, irrespective of type of label. From a practical point of view, the choice should be based on the analytical performance and on the characteristics of each assay, on its cost and the type of instrumentation available in the laboratory, and on the experience and the knowledge of the laboratory personnel.

Subcellular distribution of technetium-99m-N-NOEt in rat myocardium

The aim of this study was to determine the subcellular distribution of bis(N-ethoxy N-ethyl)dithiocarbamato nitrido technetium(V) (99mTcN-NOEt) in rat heart by differential centrifugation techniques. Extraction of the activity from homogenized rat heart tissue was also performed to assess whether myocardial retention might induce changes in the chemical identity of the complex.

METHODS

Anesthetized rats were intravenously injected with 99mTcN-NOEt, the heart tissue was extracted and homogenized and tissue fractions were obtained by differential centrifugation. The efficiency of organelle separation was determined by assay of each centrifugal fraction using enzyme markers. Lactate dehydrogenase (LDH), acid phosphatase (ACP), alkaline phosphatase (ALP) and 5'-nucleotidase (5'ND) activities were assayed using standard spectrophotometric methods. Succinic dehydrogenase (SDH) activity was determined using a p-iodo-nitrotetrazolium-linked assay. Severe cell membrane and organelle disruption were induced by prolonging the homogenization time and their effect on the subcellular distribution of 99mTcN-NOEt was studied. The activity from homogenized heart tissue was extracted using the Folch technique and analyzed by TLC and HPLC.

RESULTS

Most of the 99mTcN-NOEt activity was found to be associated with the hydrophobic components of the cell. No evidence of specific association of activity with the cytosolic and mitochondrial components was observed. Organelle and membrane cleavage did not cause release of activity into the cytosol. Approximately 90% of 99mTcN-NOEt activity was extracted from ventricular tissue and the chemical nature of 99mTcN-NOEt was not altered by uptake by myocardium.

CONCLUSION

Cell membranes are the most apparent site of localization of 99mTcN-NOEt in heart tissue.

Myocardial perfusion imaging with technetium-99m-Tc NOET: comparison with thallium-201 and coronary angiography

We compared TcN-NOET [bis(N-ethoxy, N-ethyl dithiocarbamato)nitrido 99mTc] and 201Tl images to estimate the utility of this compound in the detection of coronary artery disease (CAD).

METHODS

Twenty-five patients undergoing cardiac catheterization had stress-redistribution-reinjection 201Tl SPECT imaging, stress-delayed (2, 4 and 6 hr postinjection) and rest-delayed (4 hr postinjection) TcN-NOET SPECT imaging.

RESULTS

Nineteen patients had coronary stenosis > or = 50% and six were normal. Stress TcN-NOET and 201Tl imaging were concordant for the presence of CAD in 22/25 patients (88%, kappa = 0.76 +/- 0.20). The overall sensitivity of TcN-NOET SPECT imaging was 74% (14/19 patients) and 68% (13/19 patients) for 201Tl SPECT imaging. The specificity was 100% (6/6 patients) for both techniques. The overall agreement of TcN-NOET and 201Tl for the presence of disease in individual coronary arteries was 96% (72/75 arteries, kappa = 0.92 +/- 0.16). Segmental analysis of stress images showed a concordance in 211/225 segments (94%, kappa = 0.82 +/- 0.09). Comparison of the 4-hr images showed a concordance between 201Tl and TcN-NOET in 21/23 patients. Following TcN-NOET injection at rest, seven patients had a defect on the initial images, which had normalized 4 hr postinjection in four patients (57%).

CONCLUSION

Perfusion imaging with TcN-NOET and 201Tl gives comparable diagnostic information in patients undergoing exercise testing for assessment of CAD. Because of the normalization of myocardial activity 4 hr after injection in some patients, we conclude that TcN-NOET is a potential technetium compound equivalent to 201Tl.

[The role of muscle scintigraphy with 201Tl in the morphofunctional assessment of obliterative arterial pathology of the lower limbs]

This study was aimed at assessing the role of stress 201Tl leg scintigraphy, compared with digital angiography, in the diagnosis and prognosis of peripheral arterial obstructive disease (PAOD) before and after surgical treatment. Fifty-four patients with known PAOD in Fontaine stages IIb, III or IV submitted to revascularization (36) or lumbar ganglionectomy (18), were examined with both angiography and scintigraphy. A statistical analysis of 360 segments (thighs and calves) was performed; in particular, correlation values were derived from 216 preoperative and 144 postoperative segments (18 patients who underwent lumbar ganglionectomy were not submitted to postoperative angiography). Scintigraphy vs. angiography sensitivity (84%), specificity (80%) and diagnostic accuracy (90%) values obtained in this study are in agreement with those reported in international literature. Scintigraphy yields information on the locoregional perfusion of an angiography-demonstrated anatomic lesion, under physiologic stress, which is particularly useful in symptomatic patients with angiographically unimportant stenoses. At present, 201Tl leg scintigraphy is the only technique yielding semiquantitative data in the assessment of single muscle groups perfusion increase in Fontaine IV patients submitted to lumbar ganglionectomy. The original contribution of this study consists in the evidence of a high predictive value (p < 0.01) of scintigraphy in the calculation of pain-free intervals in the patients with successful revascularization at clinics and angiography. This finding, if confirmed, shows a possible role for 201Tl leg scintigraphy in the diagnosis of peripheral arterial obstructive disease.

[Significance and usefulness of SPECT with Tc-99m HMPAO in the diagnosis of hemicrania with aura]

It is generally agreed upon that the attacks of migraine with aura are indicative of abnormal cerebral perfusion, while the permanence of such perfusion abnormalities during the pain-free intervals of migraine remains debated. This study was aimed at assessing: 1) the presence of cerebral perfusion abnormalities also during the interictal phase and 2) the role of SPET with 99mTc HM-PAO to diagnose migraine. Twenty-eight patients (22 women and 6 men), diagnosed as having migraine with aura according to the International Headache Society (Headache Classification Committee criteria), were submitted to SPET studies, within 10 days of the last attack. 99mTc HM-PAO was used as perfusion tracer and a single head rotating gamma camera equipped with a high-resolution collimator was used for data acquisition. The qualitative analysis of SPET images showed slight hypoperfusion areas in 22 of 28 patients (79%). In 12 of 22 patients (55%) a regional correlation was observed between hypoperfusion areas and the neurologic symptoms of aura. The results of the present study are in agreement with the current physiopathologic interpretation of migraine with aura, confirming the instability of cerebral perfusion control, even with instrumental evidence of perfusion abnormalities in the interictal period. Moreover, SPET with 99mTc Hm-PAO seems to be a useful tool in the diagnostic assessment of migraine.

Brain single-photon emission tomography with 99mTc-HMPAO in neuropsychiatric systemic lupus erythematosus: relations with EEG and MRI findings and clinical manifestations

Central nervous system (CNS) involvement in patients with systemic lupus erythematosus (SLE) is often difficult to evaluate because of protean neuropsychiatric (NP) manifestations and lack of reliable diagnostic markers. In the reported study the role of single-photon emission tomography (SPET) with technetium-99m hexamethylpropylene amine oxime (HMPAO) in the evaluation of CNS involvement in SLE was assessed and the relations between SPET perfusion defects, EEG examination, magnetic resonance imaging (MRI) findings and clinical presentation were examined. Twenty SLE patients with different NP manifestations were studied. Multiple areas of hypoperfusion, especially in the territory of the middle cerebral artery, were demonstrated by SPET analysis in all 20 patients. The number of hypoperfused areas and the degree of hypoperfusion, expressed by an asymmetry index (AI), were more marked in patients with multiple NP manifestations. MRI and EEG evaluations were positive for 14 of 18 and for 12 of 20 patients, respectively. In the patients with positive SPET and MRI, 87 MRI focal lesions and 63 hypoperfused areas were found, and for 51 of these 63 at least one MRI lesion was found in the same anatomical region. SPET examination of patients with a normal EEG showed fewer hypoperfused areas and a lower degree of asymmetry compared to patients with an abnormal EEG. SPET of patients with focal EEG abnormalities showed more hypoperfused areas (difference not statistically significant) and a higher AI than did SPET of the patients with diffuse EEG abnormalities. Seven of 11 anatomical regions with focal EEG abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Quality Assessment of Tumor Marker Determinations: A Proposal for a Supraregional Scheme

The use of tumor marker tests has increased progressively in the last decade concomitant with the advent of new monoclonal antibodies and their growing use in clinical oncology for various follow-up programs. External quality assessment (EQA) schemes widely adopted in clinical chemistry, have been extended in the last decade to immunoassays of hormones and tumor markers. EQA results can provide realistic information on the quality of the assays, performed under routine conditions. The goal of this article is to report the main results and discrepancies encountered so far in External Quality Assessment programs on tumor markers.

Sister chromatid exchanges in cultured amniocytes exposed to diagnostic ultrasound in vitro

An in vitro system has been set up to study the possible genetic effects of diagnostic ultrasound (US) on the developing fetus. Amniotic cells were cultured by the in situ technique. Well established clones were exposed to US for various lengths of time using a linear array transducer within a sound transparent apparatus. Cells were then grown in the presence of 5-bromo-2'-deoxyuridine and processed for scoring the number of sister chromatid exchanges (SCE) as the cytogenetic endpoint. There was no linear relationship between the SCE frequency and the duration of US exposure. Variance analysis showed that only interindividual variability was a significant component of total variation. Neither the main effect of treatment nor the interaction effect were statistically significant. The data suggest that US delivered from a diagnostic unit to actively growing cultured fetal cells in a system closely mimicking the conditions of US exposure during amniocentesis does not induce SCE.

[Nuclear medicine in the integrated diagnosis of fatigue fractures]

Nuclear medicine applications deal with the functional and dynamic study of organs and apparatuses in each diagnostic protocol. Bone scintigraphy (diagnostic accuracy: 80%) plays an important role in the differential diagnosis of the various musculoskeletal conditions in sports, mainly in the so-called "stress syndrome". The method is rather simple, including three steps: 1) study of radioactivity in the ROI; 2) capillary phase, with early imaging; 3) bone phase, with a static image 5 hours after injection. Slight differences in marker uptake, with fusiform and elongated marker accumulation areas, can be seen in the tibial stress syndrome, which exhibits no increase in the vascular phase, while in stress fractures, mainly in the late stages, increased activity can be seen in the arteriolar and capillary phases. Stress fractures are divided into 5 stages, from stage 1 = < 20% skeletal involvement to stage 5 = complete fracture, with > 80% bone involvement. The advantages of 3-phase bone scintigraphy can be summarized as follows: 1) it yields objective information, where clinics and radiology are often negative; 2) it allows the differential diagnosis between soft tissue lesions and bone fractures even in an early stage; 3) it allows prognosis to be made and the resumption of sport activity to be planned.

Comparison between single saturating dose ligand binding assay and enzyme immunoassay for low-salt extractable oestrogen and progesterone receptors in breast cancer: a multicentre study

An excellent correlation between ligand binding assay (LBA) and enzyme immunoassay (EIA) for both oestrogen (ER) and progesterone (PR) receptors has been reported. Nevertheless, considering that the clinical value of any discrepancy between LBA and EIA probably varies with the receptor level, we undertook a collaborative study in which a single saturating dose (SSD) LBA and EIA were compared in different ER and PR dose ranges. The values of ER measured by EIA were higher in tumours with low or intermediate receptor content, causing a misclassification of ER status in 9% of cases (ER+: 77.5%, EIA, 68.8% SSD). In the case of ER, EIA values tended to be higher than SSD in all centres. For PR, EIA and SSD were generally more comparable (PR+: 66.0% EIA, 72.0% SSD, discordance rate 6%), with EIA showing, however, different trends in different centres. PR concentration was not significantly different in ER SSD-/EIA+ and in ER SSD+/EIA+ cases, suggesting that EIA detects at least in part integer ER. We conclude that although EIA may be a reliable methodological alternative to SSD, the two methods are not interchangeable until effective cut-off levels for clinical decisions are assessed for EIA.

Evaluation and comparison of the analytical performances of two RIA kits for the assay of atrial natriuretic peptides (ANP)

We evaluated the analytical performance of two commercial RIA kits for the assay of plasma atrial natriuretic peptide (ANP), which use different antisera and tracers, in order to verify the most suitable RIA procedure for the assay of ANP in plasma samples. In particular, two different procedures for the purification of plasma were evaluated. The first one uses the extraction of plasma samples with Sep-Pack C18 cartridges and the second immunoextraction (C-terminal ANP-specific antibody bound to solid phase of Sepharose). The sensitivity and precision of the two RIA kits proved inadequate, being unable to provide an acceptably precise measurement of the plasma ANP concentrations in normal subjects. An improvement in precision and sensitivity was obtained by using "fresh" (or purified) preparations of the tracer and standard solutions, and by adding PEG to the B/F separation step. The direct assay (without preliminary purification) was not possible due to a serious overestimation of plasma levels due to the presence of interferences; on the other hand, the extraction step increased the imprecision and the complexity of the assay. Moreover, the extraction recovery of ANP added to plasma samples in the procedure using Sep-Pak cartridges is about 50-60%, while it was found to be almost complete (about 90%) in the immunoextraction procedure. Moreover, a comparison of the results obtained with the two RIA systems indicated that the antisera have comparable sensitivities, but quite different specificities; however, neither of the two RIA kits showed a completely satisfactory degree of sensitivity, precision and practicability.

[Echographic diagnosis of Peyronie's disease]

Thirty-six patients with Peyronie's disease were evaluated with diagnostic sonography. Radiographic and/or xeroradiographic examinations were also performed on 23 patients. Sonography could demonstrate the presence of the plaques characteristic of the disease in the majority of cases (94.5%), whereas only calcified lesions were depicted by conventional X-rays. Sonography is therefore recommended for its well-known advantages over other techniques, not only as the diagnostic methodology of choice, but also in the follow-up of the disease.

Amiodarone and thyroid status in refractory arrhythmias

Out of 20 subjects selected for refractory arrhythmias, amiodarone therapy (200 mg/day) was efficacious in 85%. No statistically significant variations in electrocardiographic parameters (QTc) were observed; similarly, there was little evidence of side effects 1 year after initiation of treatment. These results were most likely due to the low daily dosage administered. We observed: 1) a significant increase in rT3 levels; 2) a decrease in TT3; 3) a uniform homeostasis of free fraction (FT3;FT4) These effects are all characteristic patterns of a "Low T3 Syndrome". The dosage of circulating amiodarone in 6 patients with borderline hormonal status (3 hyper- and 3 hypothyroidism) was not found to be an efficacious test for therapeutic monitoring. Identification of a statistically significant linear regression relationship between cumulative dose of amiodarone and rT3 levels may be a useful test in clinical practise for establishing more appropriate therapeutic dosages. Furthermore, it provides a guideline for threshold levels (maximum rT3 = 100-110 ng/dl) which are in close association with several side effects.