Biomedical subjects

H Schicha

Publications and source records attributed to H Schicha.

At least 145 records · Page 8Linked to original sources

PubMed1995

Comparison of low-dose dobutamine-gradient-echo magnetic resonance imaging and positron emission tomography with [18F]fluorodeoxyglucose in patients with chronic coronary artery disease. A functional and morphological approach to the detection of residual myocardial viability.

BACKGROUND: There have been conflicting reports of whether substantial myocardial thinning alone as an indirect sign of myocardial scarring is sufficient evidence to exclude the presence of viable myocardium in patients with previous myocardial infarction and persisting regional left ventricular akinesia. Demonstration of a dobutamine-induced contraction reserve in postischemic viable but akinetic myocardium may serve as a direct indicator of myocardial viability. In the present study, end-diastolic wall thickness at rest and dobutamine-induced systolic wall thickening assessed by magnetic resonance imaging (MRI) were compared with corresponding [18F]fluorodeoxyglucose uptake as assessed by positron emission tomography (FDG-PET). METHODS AND RESULTS: Thirty-five patients with myocardial infarction (infarct age, > 4 months) and regional akinesia or dyskinesia assessed by left ventriculography underwent rest and dobutamine MRI studies (10 micrograms dobutamine.min-1.kg-1) and FDG-PET followed by segmental analyses of end-diastolic wall thickness, systolic wall thickening, and FDG uptake in corresponding short-axis tomograms. Two definitions of viability, as assessed by MRI, of a segment akinetic at baseline were used: (1) end-diastolic wall thickness of > or = 5.5 mm (the mean minus 2.5 SD of a healthy control group [n = 21]) and (2) evidence of dobutamine-induced systolic wall thickening > or = 1 mm. Segments were graded as viable by FDG-PET if FDG uptake was > or = 50% of the maximum uptake in a region with normal wall motion as assessed by left ventriculography. Preserved end-diastolic wall thickness in akinetic regions was found in 17 of 35 (48%) patients at rest, and functional recovery within the infarct region was found in 19 of 35 (54%) patients during dobutamine infusion. Viability of the infarct region was indicated by FDG-PET in 23 of 35 patients (66%), yielding a diagnostic agreement between FDG uptake and myocardial morphology in 29 of 35 (83%) and between dobutamine-induced contraction reserve and FDG-PET in 31 of 35 (89%). Of 2200 segments, 482 (22%) were akinetic at rest. Of these akinetic segments, 234 (48%) had preserved end-diastolic wall thickness, 251 (52%) had a dobutamine-induced contraction reserve, and 299 (62%) were graded as viable by FDG-PET. Correlations of FDG uptake with end-diastolic wall thickness at rest (r = .48) and with dobutamine-induced wall thickening (r = .42) were similar. Comparison of segmental MRI and FDG-PET gradings indicated that dobutamine-induced wall thickening was a better predictor of residual metabolic activity (sensitivity, 81%; specificity, 95%; positive predictive accuracy, 96% than was end-diastolic wall thickness (sensitivity, 72%; specificity, 89%; positive predictive accuracy, 91%). However, grading a segment as viable if at least one of both MRI parameters fulfilled viability criteria improved the sensitivity (88%) of MRI for FDG-PET-assessed metabolic activity without a major decrease in specificity (87%) or positive predictive accuracy (92%). CONCLUSIONS: Viable myocardium is characterized by preserved end-diastolic wall thickness and a dobutamine-inducible contraction reserve. Both parameters should be taken into account to maximize the sensitivity of MRI in the detection of regions with signs of viability on FDG-PET images.

Coronary Angiography↗

PubMed1995

The role of nuclear medicine in diagnosis of catheter-related infections.

Infections represent a complication after transient or permanent implantation of medical devices (e.g. catheters or pacemaker systems), leading in many cases to therapeutic consequences such as the removal of the implanted system. Diagnosis of foreign body infections is difficult and mainly based on clinical findings rather than laboratory methods or modern morphological imaging tools. Two-dimensional echocardiography by transthoracic and transesophageal approach may be helpful in the detection of vegetations, but is not very sensitive for infections. Most methods in nuclear medicine, however, are based on function and not on form: some methods for the detection of an infection are unspecific like the use of labelled nanocolloids or Ga-67-citrate, or they need time-consuming and susceptible techniques for the labelling of autologous leukocytes. Monoclonal antibodies against epitopes on granulocytes, however, offer a fast and reliable in-vivo labelling technique. It has been demonstrated in a group of four patients that scintigraphic detection of pacemaker infections by immunoscintigraphy may represent a valuable diagnostic tool.

Animals↗

PubMed1995

The influence of various anesthetics on the release and metabolism of thyroid hormones: results of two clinical studies.

Normal functioning of the thyroid gland during surgery is important, but few data are available on the possible interactions between anesthesia and thyroid hormones. In two independent studies we examined the influence of different types of general anesthesia on the plasma levels of the thyroid hormones. They revealed an intraoperative increase of free thyroxine (fT4) and total thyroxine (tT4) in plasma to approximately 150% of preanesthesia levels when enflurane was used. No increase in thyroid-stimulating hormone (TSH) secretion was noted prior to this. The increase was not due to a quantitative change in the binding proteins. The plasma levels of fT4 and tT4 returned to normal postoperatively; however, no accompanying increase in plasma triiodothyronine levels was observed. Hence we assume the increase to be due to hormone release from thyroid and/or extrathyroidal stores--an intercompartmental shifting.

Adult↗

PubMed1995

[Biokinetics of tumor-affinity yttrium preparations--2].

After demonstrating that the application form 87Y-NTA-EDTMP-Ca is superior to the so far used citrate form of yttrium especially regarding the tumour/liver and tumour/bone ratios, the relationships between the concentrations of the components in the 87Y-NTA-EDTMP-Ca mixture and the 87Y biokinetics were investigated in tumour-bearing mice. The increase of the EDTMP and Ca2+ concentrations by several orders of magnitude caused no significant changes of tumour radioactivity but a clear radioactivity decrease in the liver, spleen and bone, respectively. The increase of the NTA concentration led also to a radioactivity decrease in all organs and tissues investigated. A significant radioactivity reduction in the tumour could be observed only after administration of rather high NTA amounts. Considerations of the tumour/background ratios depending on different compositions of the injection mixture showed the possibility of optimizing radionuclide biodistribution.

Animals↗

PubMed1995

Presurgical visualization of primary breast carcinoma with PET emission and transmission imaging.

UNLABELLED: The aim of this study was to investigate a technique that visualizes findings from PET images in a context useful for surgery. METHODS: Simultaneously acquired PET emission and transmission scans were used. By applying a multipurpose imaging, registration and rendering tool (MPM), displays of orthogonal and volume-rendered views or any combination thereof were obtained. The PET emission and transmission scans were acquired under routine conditions. The final user-customized display (with a combination of orthogonal cuts and rendered views) was processed in 10 min or less on commercially available hardware. Distinct features of the body shape were clearly visible on the volume-rendered transmission views. Hot spots, e.g., in primary breast cancer, from the emission scans could be easily assessed in their localization relative to the body outline. CONCLUSION: Rendering of the main signatures in a single comprehensive display makes this method potentially valuable for simple presurgical workup and therapeutic management of breast cancer.

Breast Neoplasms↗

PubMed1995

[Biokinetics of tumor-affinity yttrium preparations--Part 1].

Differences of yttrium biokinetics after application to male tumor-bearing mice of 87Y-citrate were studied in comparison to a 87Y-NTA-EDTMP-Ca mixture after variation of both the manner of application (intraperitoneal vs. intratumoral) and the tumor type (mamma carcinoma vs. melanoma). The application of 87Y as NTA-EDTMP-Ca preparation led--in comparison to the citrate form applied so far--to a similar radionuclide tumor accumulation and distinctly lower extratumoral radioactivities in liver, spleen and skeleton with clearly more favorable tumor/background ratios. Melanomas showed a significantly higher radioactivity accumulation (factor 2-3) after injection of 87Y-NTA-EDTMP-Ca than mamma carcinomas. Intratumoral application led to high initial radioactivities in the tumors. Radioactivity concentrations which are comparable with those after intraperitoneal application were achieved within 4 h after intratumoral application. The application of the EDTMP-containing mixture promises in comparison to the traditional citrate form higher radiation doses in the tumor related to the whole-body radiation exposure. The consequences for a possible tumor therapy will be further investigated.

Animals↗

PubMed1995

[Magnetic resonance tomography findings in adult patients with congenital corrected transposition of great arteries].

In four adult patients with congenitally corrected transposition (C-TGA) of the great arteries the typical anatomy and relevant additional lesions such as perimembranous ventricular septal defect (n = 3), secundum atrial septal defect (n = 2), sub-/valvular pulmonic stenosis (n = 3) and pulmonary artery dilatation (n = 4) and/or relevant tricuspid valve insufficiency (n = 3) were depicted by magnetic resonance imaging (MRI) using spin-echo and gradient-echo techniques. The severity of the additional lesions could be evaluated qualitatively. Therefore, in cases of C-TGA magnetic resonance imaging may provide additional information or in selected patients may serve as a useful alternative to conventional imaging techniques such as echocardiography and angiocardiography.

Adult↗

PubMed1994

Morphologic correlate of pathologic Q waves as assessed by gradient-echo magnetic resonance imaging.

To assess the morphologic correlate of the presence and absence of pathologic Q waves in the electrocardiogram, 30 patients with and 17 patients without pathologic Q waves and chronic myocardial infarction (infarct age > 4 months) and 15 patients without previous myocardial infarction but significant coronary artery disease (> 70% diameter stenoses) were studied by gradient-echo magnetic resonance imaging (MRI). Short-axis MRI tomograms were evaluated on a segmental basis by calculating end-diastolic wall thickness and systolic wall thickening. All segments were graded transmural scar (end-diastolic wall thickness < end-diastolic wall thickness of a healthy control group [n = 21]-2.5 SD and lack of systolic wall thickening), hypokinetic (end-diastolic wall thickness > or = end-diastolic wall thickness of the control group-2.5 SD and systolic wall thickening < or = 2 mm), or normal (end-diastolic wall thickness > or = end-diastolic wall thickness of the control group-2.5 SD and systolic wall thickening > 2 mm) by MRI criteria. Myocardial infarcts were defined as transmural if at least 1 segment fulfilled the MRI criteria for transmural scar. Of 30 patients with Q-wave infarction, 26 (87%) had a transmural defect, and 6 of 17 patients (35%) with non-Q-wave infarction had a transmural infarct. Segmental evaluation yielded 129 of 480 scar segments (27%) for patients with Q-wave infarction, 20 of 272 scar segments (7%) for patients with non-Q-wave infarction, and no scar segments for patients without previous myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Dobutamine 99mTc-MIBI single-photon emission tomography: non-exercise-dependent detection of haemodynamically significant coronary artery stenoses.

Dobutamine pharmacological stress testing in conjunction with technetium-99m methoxyisobutylisonitrile single-photon emission tomography (MIBI SPET) may be a useful alternative to convential exercise stress MIBI SPET for the detection and localisation of coronary artery stenoses. Therefore, 35 patients with stenoses (> or = 50% diameter reduction) of one or more coronary arteries were selected for dobutamine MIBI SPET. Each patient underwent MIBI injection at rest and during dobutamine infusion with incremental doses (5, 10, 15 and 20 micrograms kg-1 min-1). A conventional exercise stress test (EST) was performed in all patients. Peak double product during steady-state dobutamine infusion (18,200 +/- 4200 mmHg min-1) was lower (P = 0.0001) than during EST (21,700 +/- 4900 mmHg min-1). Image quality was good in all but one patient, who had to be excluded from data analysis due to excessive hepatobiliary MIBI activity. Dobutamine-induced perfusion abnormalities were observed in 30/34 MIBI SPET studies, resulting in an overall detection rate for coronary artery disease of 88%. A pathological EST was observed in 23/34 patients (68%). The detection rate of individual coronary artery stenoses was 85% (28/33) for stenosess with a severe diameter reduction (> 70%) and 50% (12/24) for stenoses with a moderate diameter reduction (> or = 50-70%). In particular, sensitivity and specificity for the detection of moderate and severe stenoses (> or = 50%) were 75%/100% for left anterior descending, 67%/95% for left circumflex and 67%/69% for right coronary artery stenoses. Dobutamine MIBI SPET is a well-tolerated, non-exercise-dependent test for detection and localisation of haemodynamically significant coronary artery stenoses.(ABSTRACT TRUNCATED AT 250 WORDS)

Constriction, Pathologic↗

PubMed1994

High sensitivity of the in vivo detection of somatostatin receptors by 111indium (DTPA-octreotide)-scintigraphy in meningioma patients.

The recent availability of isotope-labelled somatostatin analogues has allowed one to detect somatostatin receptors in normal tissue as well as in endocrine or non-endocrine cranial tumours. The purpose of the present study was to establish the value of somatostatin receptor scintigraphy using an 111Indium-labelled somatostatin analogue, octreotide, in the diagnostic work-up of meningioma patients. Twenty-two patients (16 women, 6 men, aged from 19-70 years) with newly diagnosed, residual or recurrent cranial meningiomas were examined. 111Indium-labelled DTPA-octreotide was injected i.v.. Planar and tomographic images were obtained with a gamma camera 4-6, and 24 hours after injection. In all of the meningiomas studied a high density of somatostatin receptors was detected by scintigraphy. No false negative test result was found. Due to this, a 100% predictive value of a negative test was calculated. However, when the tumours were taken in culture differing staining intensity could be seen in the light- and electron microscopic level even on individual cells of a single culture when silver intensified somatostatin-gold was used as ligand. We conclude, that in vivo somatostatin receptor scintigraphy may aid in the pre-operative differential diagnosis of skull base tumours.

Adult↗

PubMed1994

111Indium (DTPA-octreotide) scintigraphy in patients with cerebral gliomas.

Somatostatin receptors (SR) have been identified in vitro in normal brain tissue, in neuro-endocrine tumours and in cerebral gliomas WHO grade 1 or 2 by autoradiography or using somatostatin-gold conjugates. In vivo, SR detection has become possible by scintigraphy applying the somatostatin analogue octreotide, radio-labelled with 111Indium. It was supposed that expression of SR in cerebral gliomas corresponds to low grade tumour malignancy and that, in vivo, somatostatin receptor scintigraphy (SRS) could refine and improve the WHO grading system for cerebral gliomas. Nineteen patients with cerebral gliomas (grade 2: n = 8, grade 3: n = 3, grade 4: n = 8) were examined with 111In (DTPA-octreotide) to evaluate, whether SRS could improve the pre-operative estimation of tumour biology and the postoperative management. The results of SRS were related with the histological findings and with the in vitro demonstration of somatostatin-binding sites on cultured tumour cells incubated with a somatostatin-gold conjugate. In vivo, none of the patients with glioma grade 2 showed enhanced tracer uptake in the SRS, whereas in vitro SR were detected in cultured tumour tissue in 5 out of 5 cases. Every patient with glioma grade 3 or 4 demonstrated a high focal uptake of 111In (DTPA-octreotide), as shown by SRS. Three patients with glioma grade 4, additionally examined with 99mTc-DTPA, showed an increased tracer uptake within the tumour area when compared with results of SRS.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Assessment of viable myocardium by dobutamine transesophageal echocardiography and comparison with fluorine-18 fluorodeoxyglucose positron emission tomography.

OBJECTIVES: The aim of this study was to assess whether dobutamine transesophageal echocardiography can identify viable myocardium in patients with chronic myocardial infarction. BACKGROUND: Experimental and clinical studies have shown that dobutamine can recruit a contraction reserve in postischemic viable but akinetic segments, indicating that dobutamine-induced functional recovery is a potential ultrasound marker of myocardial viability. METHODS: Forty patients underwent rest and dobutamine transesophageal echocardiography (dobutamine 5, 10 and 20 micrograms/kg body weight per min) and fluorine-18 (F-18) fluorodeoxyglucose positron emission tomography at rest. Three representative short-axis tomograms and a transverse four-chamber-view were used for wall motion and F-18 fluorodeoxyglucose-uptake analysis in corresponding myocardial regions. A basally asynergic segment was considered viable by transesophageal echocardiography if dobutamine-induced systolic wall motion could be observed. Viability by positron emission tomography was defined as F-18 fluorodeoxyglucose uptake > or = 50% of the maximal uptake in a region with normal wall motion by left ventriculography. RESULTS: Functional recovery within the infarct region was found in 21 (53%) of 40 patients during dobutamine infusion. Infarct region-related viability by F-18 fluorodeoxyglucose uptake was diagnosed in 25 (63%) of 40 patients, yielding a diagnostic agreement between both techniques in 90% of patients. In 210 (89%) of 235 akinetic segments at rest, data on myocardial viability were concordant by the two techniques. The positive and negative predictive accuracy of dobutamine transesophageal echocardiography for viability defined by F-18 fluorodeoxyglucose uptake was 81% and 97%, respectively. Such uptake was significantly different (p < 0.001) between segments remaining akinetic (mean +/- SD 45 +/- 9%) during dobutamine infusion and segments with a dobutamine-induced contraction reserve (68 +/- 11%). CONCLUSIONS: Dobutamine transesophageal echocardiography provides a promising low cost and widely available approach to unmask myocardial viability in patients with chronic myocardial infarction, and results compare favorably with those of F-18 fluorodeoxyglucose positron emission tomography.

Adult↗

PubMed1994

Regional 99mTc-methoxyisobutyl-isonitrile-uptake at rest in patients with myocardial infarcts: comparison with morphological and functional parameters obtained from gradient-echo magnetic resonance imaging.

It is not yet clear whether 99mTc-methoxyisobutyl-isonitrile (MIBI)-uptake is a reliable indicator of myocardial viability, and a threshold value, differentiating viable from scarred myocardium, in comparison to a morphological and functional standard of reference has not been defined. MIBI-uptake was quantified in 800 segments from 55 patients with angiographically proven coronary artery disease with and without a history of myocardial infarction. Viable myocardium was defined from gradient-echo magnetic resonance images (MRI) as regions with systolic wall thickening or an end-diastolic wall thickness above the mean value -2.5 SD of a healthy control group (n = 21). Scar was defined as end-diastolic wall thickness > 2.5 SD below the normal mean value and absent systolic wall thickening or wall thinning. Mean MIBI-uptake of viable (n = 676; 79 +/- 14%) and scar segments by MRI (n = 124; 31 +/- 16%) was significantly different (P < 0.001). Segmental MIBI-uptake vs end-diastolic wall thickness (r = 0.7) and systolic wall thickening (r = 0.71) yielded a fair correlation. The highest values as regards sensitivity and specificity of MIBI-uptake in predicting the presence of scar were 89% and 96% respectively for MIBI-uptake < or = 50%. However, of the 136 segments with MIBI-uptake < or = 50%, 26 (19%) were viable by MRI, resulting in a positive predictive accuracy for scar tissue of 81%. Of the 26 segments diagnosed as scarred by MIBI-SPECT but viable by MRI, 25 (96%) were located in the inferoseptal region. MIBI-SPECT seems useful in the detection of viable myocardium after anterior myocardial infarcts, but over-estimates scar in the inferoseptal regions. Perfusion defects in these regions could be confirmed or denied by additional evaluation of myocardial morphology and function by MRI or tissue metabolism by positron emission tomography (PET).

Adult↗

PubMed1994

Gradient-echo magnetic resonance imaging during incremental dobutamine infusion for the localization of coronary artery stenoses.

Dobutamine pharmacological stress testing in conjunction with gradient-echo magnetic resonance imaging (MRI) may be a useful tool for the assessment of haemodynamically significant coronary artery stenoses. Therefore, 28 patients without previous myocardial infarction but significant proximal stenoses (> or = 70% diameter stenosis) of one or more coronary arteries were selected for dobutamine-MRI. Each patient underwent MRI at rest and during incremental dobutamine infusion (5, 10, 15 and 20 micrograms.kg-1.min-1). Additionally, all patients were submitted to exercise stress electrocardiography (EST). A total of 72 segments per patient obtained from identical short axis and transverse tomograms at rest and during dobutamine infusion were evaluated by two observers. Each segment was graded as normal, hypokinetic, akinetic or dyskinetic. Dobutamine-MRI was considered pathological if segmental wall motion deteriorated by at least one grade after dobutamine infusion. For comparison with coronary angiography, segmental wall motion gradings were related to the respective coronary artery territories. Peak rate-pressure product during steady-state dobutamine infusion (18.493 +/- 4.315 mmHg.min-1) was significantly lower (P < 0.01) than during EST (21.316 +/- 4.937 mmHg.min-1). Dobutamine-induced wall motion abnormalities were observed in 22/26 (85%) MR studies and 20/26 (77%) patients had a pathological EST. Regional asynergy induced by dobutamine-MRI occurred in 11/15 (73%) patients with single and 11/11 (100%) with multi-vessel disease. Sensitivity and specificity for the detection of a stenosed coronary artery were 87% and 100% for the left anterior descending, 62% and 93% for the left circumflex and 78% and 88% for the right coronary artery respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Chronic aortic dissection: comparison of MR Imaging and transesophageal echocardiography.

PURPOSE: To compare the diagnostic value of magnetic resonance (MR) imaging and transesophageal echocardiography (TEE) in the follow-up of chronic dissection of the thoracic aorta. MATERIALS AND METHODS: Follow-up MR imaging and TEE were performed in 25 consecutive patients with aortic dissection. Ten patients had a type I dissection and 15 had a type III dissection. All patients with type I dissection underwent surgical intervention. Ten of 15 type III dissections were managed medically, and five were managed with surgical intervention. RESULTS: Identification of a persisting dissection and differentiation of the true and false lumina were equal with both methods. The arch vessels and all anastomoses in the surgically treated patients could be assessed only with MR imaging. An intimal flap in the aortic root and formation of an aortic thrombus were visualized in more detail with TEE. At least one entry site could be detected with both methods in 86% of the patients. TEE demonstrated small entry sites more frequently. CONCLUSION: MR imaging provides better visualization of anastomoses and easier comparison of serial studies; TEE should be employed if MR findings are equivocal.

Adult↗

PubMed1994

Coronary artery disease: findings with GRE MR imaging and Tc-99m-methoxyisobutyl-isonitrile SPECT during simultaneous dobutamine stress.

PURPOSE: This study compared gradient-recalled echo (GRE) magnetic resonance (MR) imaging with technetium-99m-methoxyisobutyl isonitrile (MIBI) single photon emission computed tomography (SPECT) during the same dobutamine stress for the localization of coronary artery stenoses. MATERIALS AND METHODS: In 35 consecutive patients (28 men and seven women, aged 41-79 years) with angiographically documented coronary artery disease, corresponding GRE MR images and SPECT tomograms were acquired at rest and during dobutamine infusion and were evaluated for regional wall motion or perfusion abnormalities. RESULTS: Images in both examinations could be analyzed in 32 of 35 (91%) patients. Wall motion or perfusion abnormalities were observed in 27 of 32 (84%) GRE MR imaging and in 28 of 32 (87%) SPECT examinations. Sensitivity and specificity of dobutamine GRE MR imaging and dobutamine SPECT for the localization of left anterior descending coronary artery stenoses were 74% and 100% versus 70% and 100% for the combined left circumflex and right coronary artery perfusion territories. CONCLUSION: GRE MR imaging and SPECT have a high concordance with respect to the detection of a dobutamine-induced ischemic response.

Constriction, Pathologic↗

PubMed1994

[Quality assurance in cardiology: nuclear medicine].

Quality control as regards nuclear medicine heart studies refers to two areas: methodological quality control clinical quality control. Methodological correct realization of nuclear medicine heart studies is the first prerequisite for validity of the results. The term "myocardial scintigraphy" summarizes several different procedures. Concerning clinical routine, myocardial scintigraphy stands for imaging of microcirculation and scars using Tl-201-chloride or Tc-99m-MIBI, additionally for metabolic assessment of myocardial viability with F-18-FDG. Today, planar myocardial scintigraphy has been replaced by tomographic techniques (SPECT, PET). Methodological procedures for quality control concerning technical equipment and radiopharmaca are based on the new "guidelines for radiation exposure in medicine" of 1993. Clinical quality control in myocardial scintigraphy covers, in particular, the correct selection of indications: proof/exclusion of coronary artery disease (depending on prevalence) specific questions before interventional therapy (myocardial ischemia, myocardial viability) follow-up and therapy control. Selection of the procedure for myocardial scintigraphy depends on the clinical question. However, different methodological strategies are under discussion. Adequate preparation of the patient and realization of the investigation (withdrawal of medication, selection of type and intensity of stress) are prerequisites for valid results. Interpretation has to consider that myocardial scintigraphy represents different parameters than, for example, coronary morphology. False positive as well as false negative results can occur due to methodological and biological causes. Optimization of methodological and clinical quality control in nuclear medicine heart studies requires a close and competent co-operation of cardiologists and nuclear medicine physicians.

Cardiomyopathies↗

PubMed1994

[Magnetic resonance imaging in screening for bone metastasis? A prospective comparison with bone scintigraphy].

To define the value of magnetic resonance imaging (MRI) in screening for bone metastases (BM) compared to bone scintigraphy (BSc) 102 patients with tumours with frequent BM were examined also by MRI of spine, pelvis, femora, and proximal tibiae. All patients had normal BSc and 96 (94%) normal MRI. Only 6% of the patients had focal abnormalities within the bone marrow. This indicates that there is a 94% probability of absence of BM if BSc is normal. Therefore, BSc should currently remain the method of choice for screening for BM. Despite MRI is sensitive and specific, with the common technique up to now it should not be used instead of BSc in screening because of costs, duration, and lack of whole body examination. MRI is a valuable adjunct in equivocal findings in BSc with negative results on radiographs.

Bone Marrow↗