ABSTRACT
By describing 10 new patients recruited in centres for Human Genetics, we further delineate the clinical spectrum of a Crouzon-like craniosynostosis disorder, officially termed craniosynostosis and dental anomalies (MIM614188). Singularly, it is inherited according to an autosomal recessive mode of inheritance. We identified six missense mutations in IL11RA, a gene encoding the alpha subunit of interleukin 11 receptor, 4 of them being novel, including 2 in the Ig-like C2-type domain. A subset of patients had an associated connective tissue disorder with joint hypermobility and intervertebral discs fragility. A smaller number of teeth anomalies than that previously reported in the two large series of patients evaluated in dental institutes points toward an ascertainment bias.
Subject(s)
Craniofacial Dysostosis/genetics , Genes, Recessive , Interleukin-11 Receptor alpha Subunit/genetics , Adolescent , Adult , Child , Child, Preschool , Craniofacial Dysostosis/diagnostic imaging , Female , Humans , Magnetic Resonance Imaging , Male , Mutation, MissenseABSTRACT
In this article, we respectively describe the morphology of the spinal cord, spinal meningeal layers, main fiber tracts, and both arterial and venous distribution in order to explain signs of spinal cord compression. We will then describe a surgical technique for spinal cord tumor removal.
Subject(s)
Meninges/anatomy & histology , Spinal Cord Neoplasms/pathology , Spinal Cord Neoplasms/surgery , Spinal Cord/anatomy & histology , Spinal Cord/surgery , Humans , Meninges/surgery , Neurosurgical Procedures/methods , Spinal Cord/blood supplyABSTRACT
Pituitary metastases are uncommon, ranging from 1 to 5 % of all metastases. Between 10 and 30 % of pituitary lesions are symptomatic responsible for diabetes insipidus, visual field defect or cranial nerve palsy. Primary sites are lung or breast in two-thirds of cases. There is no current reference concerning treatment of such lesions. Overall survival is poor and depends on primary site. Although the role of surgery is currently limited, discussion is warranted in several indications for diagnostic or symptomatic purposes. We report two cases of symptomatic pituitary metastases in a context of breast cancer and review the litterature concerning the role of surgery and other treatment modalities.
Subject(s)
Breast Neoplasms/pathology , Pituitary Neoplasms/secondary , Pituitary Neoplasms/surgery , Breast Neoplasms/drug therapy , Female , Humans , Middle Aged , Neurosurgical Procedures , Pituitary Neoplasms/drug therapy , Pituitary Neoplasms/pathology , Treatment OutcomeABSTRACT
INTRODUCTION: We present a prospective series of tuberculum sellae meningioma (TSM) resected via a superior interhemispheric (IH) approach in 10 patients who preoperatively and postoperatively underwent extensive olfaction testing using a standardised test battery. PATIENTS AND METHODS: This prospective longitudinal study evaluated the olfactory function after TSM resection. The resection was performed via a superior interhemispheric (IH) approach. The quantitative and qualitative analyses of the olfactory function were assessed with the Biolfa(®) olfactory test (at 6 months). RESULTS: Between November 2009 and April 2012, 10 consecutive patients with symptomatic TSM and preserved olfactory function were operated via a superior IH approach. For the self-evaluation criteria of the olfactory function, the mean preoperative visual analog scale score was 8.8. The mean preoperative total quantitative (/27) scored 18.2 ± 6.3 for this cohort of 10 patients. In the postoperative period, the mean total score decreased non-significantly to 15.8 ± 8.8 (Wilcoxon test, P = 0.085). The mean preoperative qualitative score (/8) was 5.5 ± 1.7 and in the postoperative period decreased, non-significantly, to 4.7 ± 2.6 (Wilcoxon test, P = 0.12). The olfactory function was quantitatively and qualitatively preserved in 6 patients (60%), but a postoperative deterioration occurred in 2 (20%) and an anosmia in 2 (20%). Size and invasive characteristics of the meningioma determined the post-surgical deterioration. CONCLUSION: Olfaction is an important factor of emotional and social life, which needs to be integrated into the challenge regarding the resection of TSM. The risks of nerve damage are reviewed.
Subject(s)
Meningeal Neoplasms/surgery , Meningioma/surgery , Olfactory Tubercle/physiopathology , Skull Base Neoplasms/surgery , Smell/physiology , Adult , Aged , Female , Humans , Male , Meningeal Neoplasms/diagnosis , Meningioma/diagnosis , Middle Aged , Neurosurgical Procedures/adverse effects , Olfaction Disorders/diagnosis , Olfaction Disorders/etiology , Olfactory Tubercle/surgery , Prospective Studies , Skull Base Neoplasms/diagnosis , Supratentorial Neoplasms/diagnosis , Supratentorial Neoplasms/surgery , Treatment OutcomeABSTRACT
The ageing of the population in good health or without severe morbidity expose them to the occurrence of a subarachnoid hemorrhage (SAH) and requires effective management. Currently, the pertinence of cerebral aneurysm treatment by clipping or coiling is accepted for patients in the 8th or 9th decade of life, and the risk of postoperative morbidity induced by our therapeutic alternative must be carefully assessed. In these decades, the female/male sex ratio for aneurysmal SAH was greater in female who had a 1.6 times higher ratio than in male. The initial clinical status did not appear worse with age despite the frequent severity of bleeding observed on CT scan probably due to the large subarachnoid space. The aneurysm distribution and size were similar to those classically reported in the global population. The endovascular (EV) coiling appears as the first option with a favorable outcome rate estimated at 48% to 63%. Nevertheless, the benefit of EV coiling compared to microsurgical clipping for treatment of ruptured aneurysm in the elderly has not been demonstrated in a large randomized study. This is the reason why the vascular section of the French Society of Neurosurgery developed a prospective and randomized study of the aneurysmal SAH (PHRC 2007-042/HP) on the elderly patients.
Subject(s)
Embolization, Therapeutic/methods , Intracranial Aneurysm/therapy , Subarachnoid Hemorrhage/therapy , Aging , Endovascular Procedures/methods , Humans , Intracranial Aneurysm/complications , Subarachnoid Hemorrhage/etiology , Treatment OutcomeABSTRACT
We present a case of a rebleeding remote from a vertebral artery dissection associated with subarachnoid haemorrhage. A 7-year-old boy without any antecedent presented a traumatic dissection of the vertebral artery with subarachnoid haemorrhage. After a conservative treatment, the morphology of the vertebral artery became normal and the boy was asymptomatic. Four months later, a rebleeding occurred on the same vertebral artery, whose morphological review was normal. Mechanisms and cases of rebleeding in the literature are discussed. An inflammatory vasculopathy was suspected and discussed.
Subject(s)
Subarachnoid Hemorrhage/etiology , Subarachnoid Hemorrhage/surgery , Vertebral Artery Dissection/complications , Vertebral Artery Dissection/surgery , Child , Humans , Inflammation/etiology , Male , Recurrence , Subarachnoid Hemorrhage/therapy , Vertebral Artery/pathologyABSTRACT
BACKGROUND: The purpose of this study is to report the first clinical results obtained with the spectral deconvolution technique photon energy recovery (PER) for crosstalk correction in simultaneous rest thallium 201/stress technetium 99m sestamibi myocardial perfusion single photon emission computed tomography (SPECT). METHODS AND RESULTS: Thirty-four patients with suspected coronary artery disease received Tl-201 (111-130 MBq) at rest, followed by single SPECT. Tc-99m sestamibi (444-518 MBq) was then injected at stress, followed by dual SPECT. Single SPECT data were processed to obtain the following data sets: single raw (conventional) Tl-201 and single PER (scatter-corrected) Tl-201. Dual SPECT data were processed to obtain the following data sets: dual raw Tl-201, dual PER (scatter- and crosstalk-corrected) Tl-201, dual raw Tc-99m, and dual PER (scatter-corrected) Tc-99m. All data sets were automatically analyzed with Cedars-Sinai Quantitative Perfusion SPECT software to derive the relative segmental uptake, the summed score, and the summed difference score. The relative segmental uptake, the summed score, and the number of patients with significant reversibility (summed difference score >2) were 74.84% +/- 12.79%, 3.44 +/- 3.07, and 13, respectively, for single raw Tl-201; 80.5% +/- 10.18%, 1.97 +/- 2.25, and 20, respectively, for dual raw Tl-201; 69.47% +/- 14.08%, 6.41 +/- 3.68, and 17, respectively, for single PER Tl-201; and 69.99% +/- 13.39%, 6.58 +/- 3.63, and 17, respectively, for dual PER Tl-201. The differences between single and dual raw Tl-201 data sets were highly significant, whereas there was no significant difference between PER-corrected Tl-201 data sets. CONCLUSIONS: PER is quantitatively efficient to correct for crosstalk in patients investigated with simultaneous rest Tl-201/stress Tc-99m sestamibi myocardial SPECT.
Subject(s)
Coronary Disease/diagnostic imaging , Dipyridamole , Exercise Test , Heart/diagnostic imaging , Radiopharmaceuticals , Technetium Tc 99m Sestamibi , Thallium Radioisotopes , Tomography, Emission-Computed, Single-Photon , Vasodilator Agents , Aged , Female , Humans , Image Processing, Computer-Assisted , Male , Middle Aged , RestABSTRACT
UNLABELLED: Simultaneous 99mTc sestamibi/201Tl imaging enables the acquisition of images of myocardial stress perfusion and myocardial viability in a single process. One of the major limits of this technique is the crosstalk of the 99mTc downscattered photons into the 201Tl window. We propose using the spectral deconvolution technique photon energy recovery (PER) for correcting this crosstalk. METHODS: A planar line phantom made of 99Tc vertical lines and 201Tl horizontal lines and a cardiac SPECT phantom including an anterior (2 mL) and an inferior (1.5 mL) myocardial fixed defect were used. The phantoms were filled with an initial 99mTc/201Tl ratio of 5:1. Several successive acquisitions were made from time t = 0 to time t = 48 h (99mTc/201Tl ratio approximately 0) without moving the phantoms. Total number of counts, contrast, and normalized SD (NSD) were calculated on the Tl-raw and the Tl-PER planar images. SPECT datasets were analyzed. The Tl-raw images recorded at 48 h were considered the reference "virgin" 201Tl images. RESULTS: Total number of counts, contrast, and NSD ranged from 336% to 201%, 15% to 29%, and 257% to 225% of the virgin 201Tl values, respectively, for Tl-raw planar images; whereas values for Tl-PER images ranged from 128% to 108%, 61% to 79%, and 154% to 108%, respectively. Anterior and inferior defect contrasts ranged from 1.18 to 1.22 and 1.12 to 1.16 for Tl-raw SPECT images, respectively; whereas for Tl-PER images, value ranges were 1.28-1.32 and 1.21-1.24, respectively. The corresponding reference virgin 201Tl values were 1.31 and 1.25 respectively. Summed score, average defect severity, and average defect extent ranges were 4-5, 0.4-0.52, and 4.7-5.9 for Tl-raw images, respectively, and 8-9, 0.59-0.79, and 7.4-8.8 for Tl-PER images. The reference virgin 201Tl values were 9, 0.73, and 8.7, respectively. CONCLUSION: PER is quantitatively efficient to remove 99mTc crosstalk photons from 201Tl images for 99mTc/201Tl ratios ranging from 5:1 to 2:1.
Subject(s)
Heart/diagnostic imaging , Technetium Tc 99m Sestamibi , Thallium Radioisotopes , Tomography, Emission-Computed, Single-Photon/methods , Humans , Image Processing, Computer-Assisted , Phantoms, Imaging , Photons , Radiopharmaceuticals , Scattering, RadiationABSTRACT
UNLABELLED: One of the major limitations of gamma cameras is their relatively poor energy resolution. The main practical consequence of this is that the detection of both scattered and unscattered photons in the photopeak energy window, affecting image contrast and resolution, makes the data inconsistent with the assumption of scatter-free projection data in reconstruction and attenuation correction algorithms. Here, we proposed a method to improve the effective energy resolution of scintigraphic acquisitions. This method is called photon energy recovery (PER). METHODS: Photon energy recovery is based on a spectral deconvolution analysis and uses iterative recurrent linear regressions. In practice, PER only required splitting the photopeak energy window into several subwindows and did not need list mode acquisitions. The method was fully automated. Photon energy recovery was quantitatively validated on 99mTc planar images using a Monte Carlo simulation and a real phantom and was illustrated by a bone study. RESULTS: The Monte Carlo simulation demonstrated that convergence was reached within relatively few (10-15) iterations. Photon energy recovery led to a considerable quantitative improvement because the mean error between the photopeak energy window image and the true unscattered image was equal to 8.72 s.d. (the mean error between one image and the true image was the mean of the differences between the two images; the difference is expressed as several s.d., where s.d. was the square root of the true value), whereas the mean error between the 140-keV PER image and the true unscattered image was only equal to 2.70. Moreover, the true and PER spectra were highly correlated. The real phantom data pointed out that the counts in the 140-keV PER image calculated from the images acquired "with scatter" were not very different from the true counts given by the "scatter-free" reference image. Planar pelvic bone scintigraphy demonstrated the advantages of PER because contrast increased when only unscattered photons were selected. CONCLUSION: Photon energy recovery is a stable and automated method that allows recovery of the correct value of the photon energy after a scintigraphic acquisition. Its ability to separate scattered from unscattered events has been quantitatively validated.
Subject(s)
Gamma Cameras , Image Processing, Computer-Assisted , Tomography, Emission-Computed, Single-Photon , Algorithms , Computer Simulation , Humans , Monte Carlo Method , Phantoms, Imaging , Scattering, Radiation , Tomography, Emission-Computed, Single-Photon/instrumentation , Tomography, Emission-Computed, Single-Photon/methodsABSTRACT
A new method for the enhancement of smoothing filters has been developed. It is an iterative and non-stationary (INS) process by which averaging is limited only to pixels that are 'statistically consistent' with the central pixel of the filter window. Adjustment of filter performance is achieved by the iterative calculation of filtered data variance. INS versions of the 25-point weighted and Butterworth filters have been validated and compared with their classical stationary versions using a numerical phantom and clinical data. The iterative procedure converges well after two or three iterations and produces more smoothing without any loss of contrast or resolution. Qualitative and quantitative results show that, unlike the stationary versions, the INS versions of the filters do not impede the detection of small or low-contrast objects and do preserve the contours of anatomical structures. In 99Tcm myocardial single photon emission tomography, the INS version of the Butterworth filter can be used with the same order and critical frequency, whether data have been recorded at rest (data with a high level of noise) or at stress (data with a low level of noise). In conclusion, INS filters enable noise reduction while maintaining contrast and resolution in filtered images. The procedure can be easily applied to any smoothing filter.
Subject(s)
Phantoms, Imaging , Radionuclide Imaging/instrumentation , Radionuclide Imaging/methods , Tomography, Emission-Computed, Single-Photon , Bone and Bones/diagnostic imaging , Equipment Design , Exercise Test , Heart/diagnostic imaging , Humans , Models, Theoretical , Organophosphorus Compounds , Organotechnetium Compounds , Radiopharmaceuticals , Technetium Tc 99m Medronate/analogs & derivativesABSTRACT
A new approach to simultaneous spatial resolution and attenuation correction in SPECT imaging is presented. Before these corrections, scatter is removed on the projections. This removal is performed by spectral constrained factor analysis. The innovation reported here is the use of the different impulse responses of the system, according to the source-detector distance, and their integration in a generalized version of the Chang attenuation correction method. This novel algorithm is evaluated on computed and physical phantoms. In the computer-simulated phantom, the count rates after full-processing are very close to the initial values. In the physical phantom, the contrast is increased by 1.8 after full processing. The activity profiles drawn both on raw projections and reconstructed slices demonstrate the effectiveness of the algorithm for the restoration of spatial resolution. Furthermore, the method improves the quality of the images greatly. A clinical study is also presented. When the whole procedure is applied, the resulting slice matches the corresponding computed tomographic scan very well, which is not the case with the usual back-projected images. The process is fully automatic and the computing time performance allows its daily use for single photon emission tomographic examinations.
Subject(s)
Tomography, Emission-Computed, Single-Photon/methods , Algorithms , Computer Simulation , Factor Analysis, Statistical , Humans , Liver Neoplasms/diagnostic imaging , Liver Neoplasms/secondary , Models, Structural , Technetium Tc 99m Sulfur ColloidABSTRACT
Multivariate survival analysis (MSA) was applied to 97 patients with coronary disease using the Cox model and a stepwise regression procedure. Seventeen variables including data based upon clinical examination, exercise testing (ET), and exercise angioscintigraphy (EAS) as well as coronary arteriography were studied in each patient. During the monitoring period (interval: 1-57 months), 38 patients sustained a cardiac event (recurrence of coronary disease or death). Neither resting left ventricular ejection fraction, nor coronary anatomy were significant prognostic variables. The only two variables identified by MSA were a variable of EAS: corrected ejection fraction at maximum exercise (p less than 0.008), and a variable of ET: maximum heart rate during exercise (p less than 0.03). This study shows that the prognosis of a coronary disease patient can best be assessed by two variables which are both exercise parameters.
Subject(s)
Coronary Disease/diagnostic imaging , Radionuclide Angiography , Adult , Aged , Exercise Test , Female , Humans , Male , Middle Aged , Multivariate Analysis , Prognosis , RadiographyABSTRACT
The removal of Compton scattered photons included within the pulse height window is recognized as one of the most difficult noise problems in the restoration of nuclear medicine images. A new approach to Compton scatter correction based on factor analysis of dynamic structures (FADS) is presented in this study. The method requires all of the energy information. Acquisition of data can be performed either by list-mode or frame-mode. While the former presents some theoretical advantages, the latter is actually used in this work. Two factors are extracted by FADS, unfortunately no pure photopeak factor can be found by the algorithm. These rough factors lead to incorrect factor images. The innovation reported here is the use of a constrained photopeak factor. This novel algorithm is evaluated both on planar imaging and SPECT data using Monte Carlo simulations and real phantoms. A comparison with the modified method of Jaszczak is also presented. Different parameters are significantly improved with our recombination method in SPECT studies, particularly after attenuation compensation by the iterative method of Chang. Compared with the subtraction method the contrast is increased by 1.5 for planar Monte Carlo simulations and the scatter fraction is reduced four times with our recombination method.
Subject(s)
Tomography, Emission-Computed, Single-Photon/statistics & numerical data , Algorithms , Biophysical Phenomena , Biophysics , Factor Analysis, Statistical , Humans , Models, Structural , Monte Carlo Method , Scattering, RadiationABSTRACT
An original and entirely automatic algorithm is proposed to select regions of interest (ROIs) on dynamic scintigrams. This algorithm is based on factor analysis and on cluster analysis. It consists of first extracting the orthogonal factor images of the series using factor analysis of correspondence. These factor images are then automatically segmented in ROIs using a hierarchical ascendant classification procedure. The distance used for the classification is the 'minimum added intra-class variance' distance. This algorithm has been implemented on a fast computer dedicated to nuclear medicine (Nodecrest Micas V system). The time of calculation on 1000 pixels from 40 images is less than 5 min when three factor images are used. This algorithm is validated using a numerical phantom and is illustrated using renal (99Tcm DTPA) and cardiac (equilibrium gated angiography) dynamic scintigraphies. The results show that the algorithm is able to recognize the bladder, the renal cavities and the renal parenchyma on the renal series, and the ventricules and the atria on the cardiac series.
Subject(s)
Algorithms , Image Processing, Computer-Assisted , Radionuclide Imaging/statistics & numerical data , Cluster Analysis , HumansABSTRACT
A major drawback of In-111-labeled monoclonal antibodies (MoAb) is the presence of intense liver, renal, and bone marrow nonspecific activity. This makes the display of the images hardly optimal and their visual interpretation difficult. In this study, the "intrinsic color scale" (which consists of selecting the limits of the color scale as the highest and the lowest pixel value of the image) was compared to a new, simple algorithm for the determination of the limits of the color scale. This algorithm was based on the count density in the iliac crest areas. OC-125 or anti-CEA In-111 MoAb F(ab')2 fragments were used in 32 patients with suspected recurrence of ovarian (19 patients) or colorectal cancer (13 patients). Final diagnosis was assessed by surgery (21 patients), biopsy (five patients), or followup (six patients). A 10-minute abdomino-pelvic anterior view was recorded two days after injection. These views are displayed using the two methods and interpreted by two observers. Using their responses in each quadrant of the pelvis, the authors calculated two ROC curves. The comparison of the ROC curves showed better performances for the new method. For example, for the same specificity (73%), the sensitivity of the new method was significantly better (78% versus 68%). This result confirmed the importance of a good methodology for displaying immunoscintigraphic images.
Subject(s)
Antibodies, Monoclonal , Colorectal Neoplasms/diagnostic imaging , Indium Radioisotopes , Neoplasm Recurrence, Local/diagnostic imaging , Ovarian Neoplasms/diagnostic imaging , Algorithms , Female , Humans , Middle Aged , ROC Curve , Radionuclide ImagingABSTRACT
Data of clinical examination, exercise electrocardiography and stress radionuclide angiography in 102 patients referred for assessment of chest pain was included in a logistic regression to optimise the diagnosis of coronary artery disease with coronary angiography as the reference investigation. None of the patients had other cardiac problems nor previous myocardial infarction. In the absence of symptoms exercise testing was continued until at least 80 p. 100 of the theoretical maximal heart rate was attained. Each patient was characterised by the value of the logistic function or probability of coronary artery disease. A threshold value corresponding to 80 p. 100 sensitivity was determined by the technique of ROC graphs. The significant variables were: a clinical variable--the type of chest pain as assessed by the clinical history; two radionuclide angiographic variables--the ejection fraction at peak effort and the corrected variation of ejection fraction between rest and stress, that is not taking into account possible decreases at the last increment of exercise. Coronary patients can be identified with an 80 p. 100 sensitivity and 77 p. 100 specificity on these criteria. This specificity is greater than that obtained by clinical examination and exercise electrocardiography alone (65 p. 100). Stress radionuclide angiography may therefore reduce the number of unnecessary coronary angiographies.
Subject(s)
Coronary Disease/diagnosis , Adult , Aged , Coronary Disease/complications , Coronary Disease/diagnostic imaging , Evaluation Studies as Topic , Exercise Test , Female , Humans , Male , Middle Aged , ROC Curve , Radiography , Radionuclide Angiography , Regression AnalysisABSTRACT
A stepwise logistic regression (SLR) was performed on 162 patients with a solitary and cold thyroid nodule in order to discriminate between malignant and benign lesions. Sixteen variables were recorded for each patient. The predictions of the logistic regression model were compared to the histological diagnoses in order to evaluate the accuracy of the classification. The value of the logistic function (LF) was calculated for each patient. Using the ROC curve approach, an optimum threshold value (OTV) corresponding to a 100% sensitivity was defined. The classification obtained with the OTV was validated using a cross-validation procedure (CVP). The significant variables selected by the SLR are (from the most significant to the least significant): cytologic result, sex, irregular margin on the Tc scintigraphy and homogeneity on the ultrasound examination. The OTV corresponds to a specificity of 73% for a sensitivity of 100%. The specificity and the sensitivity obtained with the CVP are 73% and 96% respectively. In conclusion, the classification of the patients according to the value of the LF is a highly accurate diagnostic procedure.
Subject(s)
Thyroid Neoplasms/pathology , Adult , Diagnosis, Differential , Female , Humans , Male , Mathematics , Models, Biological , Thyroid Diseases/diagnosis , Thyroid Neoplasms/diagnosisABSTRACT
The aim of this work is to explore the patients operated on for a femoro popliteal bypass (FPB) with lymphoscintigraphy (LS) of the lower limbs. Data concerning 35 limbs from 33 patients operated on for a FPB have been included in a prospective study. Superficial and deep LS have been performed by injecting 74 MBq 99mTc-Rhenium Sulphide Colloid into the subcutaneous tissue of the first interdigital space and of the lateral malleolus region respectively. Both superficial and deep LS have been performed before and after surgery. A postoperative oedema was found in 17 of the 35 limbs. The value of the lymphatic flow indices and their variation after surgery do not significantly differ between the oedematous and non oedematous groups. Thirteen of the 17 limbs with oedema have presented an interruption of the lymphatic circulation or a diffuse activity outside the lymphatic vessels on the postoperative superficial and/or deep LS. This proportion is only 1/18 in the non oedematous group. The difference between the two groups is highly significant (P less than 0.001). By contrast, the proportion of lymph cyst does not differ significantly between the two groups. In conclusion, this study confirms the close relationship between the oedema following FPB and surgical damage to the lymphatics.
Subject(s)
Femoral Artery/surgery , Leg/diagnostic imaging , Lymphoscintigraphy , Popliteal Artery/surgery , Postoperative Complications/diagnostic imaging , Colloids , Edema/diagnostic imaging , Female , Humans , Male , Middle Aged , Prospective Studies , Rhenium , Technetium Tc 99m Sulfur ColloidABSTRACT
Recently proposed image comparison software is applied to immunoscintigraphy. The software performs geometric and gray level registration of two images and generates an image of the statistically significant differences. It permits the comparison of scintigraphic images recorded at different times. It is used to subtract 113mIn and 111Inphytate colloid liver scans and early (blood pool) images from 131I or 111In-monoclonal Ab images and to compare Ab images recorded at different times. Using the procedures made possible by this software, only images recorded using the same radionuclide or using radionuclides of about the same energy are compared. Anti CEA, 19-9 and OC 125 F(ab)2 fragments labeled with 131I or 111In are used in 32 patients with 47 demonstrated recurrences or metastases of colorectal or ovarian cancers. The overall sensitivities of the unprocessed and processed images are 25/47 and 41/47 respectively. The improvement in sensitivity is particularly high in the liver when In labelled Ab are used. This technique improves the contrast of the images, but the interpretation must take into account the components of the non target activity (kidney, bone marrow, colon...) which are not removed by the image subtraction method.