[A very rare submucosal tumour of the rectum - primary endometrioid adenocarcinoma of the rectum wall]. / Ein sehr seltener submuköser Tumor des Rektums - primäres endometrioides Adenokarzinom der Rektumwand.

A 56-year-old female, with a past history of hysterectomy 13 years previously due to uterine myomata, presented with complaints of pain around the anus of a few months duration. Three years previously she underwent a colonoscopy, which was found to be unremarkable. A high suspicion of a submucosal tumour of the rectum in endoscopic examinations was confirmed by endoscopic ultrasound. The biopsy could not specify the tumour characteristics. Based on the diagnosis of a 4 cm submucosal tumour with infiltration of bowel wall and regional lymph nodes the affected segment was resected. Histolopathology revealed an adenocarcinoma involving tissue from the outer bowel wall to the submucosa. However, immunohistochemistry revealed an endometrioid adenocarcinoma, suspicious for primary endometrioid adenocarcinoma of the ovary with rectum metastasis in the absence of a uterus. But this assumption could not be confirmed in the excised ovary. The tumour cells were immunopositive for cytokeratin 7, CA 12 - 5, vimentin and oestrogen receptor, but negative for cytokeratin 20 and CDX-2. Ultimately, we report a very rare case of primary endometrioid adenocarcinoma arising in endometriosis in the rectum wall and presenting as a submucosal tumour.

[Direct percutaneous radiologic jejunostomy (PR) and duodenostomy: a retrospective analysis]. / Die direkte perkutane radiologische Jejunostomie (PRJ) und Duodenostomie: eine retrospektive Auswertung.

PURPOSE: To present our experience with direct percutaneous radiologic duodenostomy and jejunostomy (PRJ) for alimentation. MATERIALS AND METHODS: A retrospective study identified 24 patients who had undergone percutaneous jejunostomy or duodenostomy guided by CT and fluoroscopy over a period of 9 years. Whenever possible, the jejunum was inflated with a 5 French diagnostic catheter and jejunopexy was performed using Cope anchors (T-fasteners). A 12 to14 French locking pigtail drain was inserted for alimentation. In 8 patients, percutaneous direct jejunostomy was performed using only fluoroscopy. In 9 patients, both CT and fluoroscopy were used to guide the jejunostomy. In all 7 patients who underwent duodenostomy, a combination of CT and fluoroscopy was used. The reports were reviewed for complications and the technical success rate. The technical success rate was determined. RESULTS: Percutaneous radiologic jejunostomy was attempted in 17 patients and failed in 5 patients. PRJ was successful in all 8 procedures guided by fluoroscopy and in 4 of 9 procedures guided by CT and fluoroscopy. Direct percutaneous duodenostomy guided by CT and fluoroscopy was successful in all 7 cases. There were no procedure-related laparotomies and no mortality related to the jejunostomy. Minor complications were infection of the abdominal wall (n = 1), lingering pain requiring a new jejunostomy (n = 1) and aspiration because of persistent reflux (n = 1). CONCLUSION: PRJ is a safe procedure even in critically ill patients. It is technically difficult and may fail if the jejunum cannot be distended. Percutaneous radiologic duodenostomy and jejunostomy are recommended for prolonged alimentation of malnourished patients following esophageal or gastric surgery.

[Self-organizing neural networks for automatic detection and classification of contrast (media) enhancement of lesions in dynamic MR-mammography]. / Selbstorganisierende neuronale Netze zur automatischen Detektion und Klassifikation von Kontrast(mittel)-verstärkten Läsionen in der dynamischen MR-Mammographie.

PURPOSE: Investigation and statistical evaluation of "Self-Organizing Maps," a special type of neural networks in the field of artificial intelligence, classifying contrast enhancing lesions in dynamic MR-mammography. MATERIAL AND METHODS: 176 investigations with proven histology after core biopsy or operation were randomly divided into two groups. Several Self-Organizing Maps were trained by investigations of the first group to detect and classify contrast enhancing lesions in dynamic MR-mammography. Each single pixel's signal/time curve of all patients within the second group was analyzed by the Self-Organizing Maps. The likelihood of malignancy was visualized by color overlays on the MR-images. At last assessment of contrast-enhancing lesions by each different network was rated visually and evaluated statistically. RESULTS: A well balanced neural network achieved a sensitivity of 90.5 % and a specificity of 72.2 % in predicting malignancy of 88 enhancing lesions. Detailed analysis of false-positive results revealed that every second fibroadenoma showed a "typical malignant" signal/time curve without any chance to differentiate between fibroadenomas and malignant tissue regarding contrast enhancement alone; but this special group of lesions was represented by a well-defined area of the Self-Organizing Map. DISCUSSION: Self-Organizing Maps are capable of classifying a dynamic signal/time curve as "typical benign" or "typical malignant." Therefore, they can be used as second opinion. In view of the now known localization of fibroadenomas enhancing like malignant tumors at the Self-Organizing Map, these lesions could be passed to further analysis by additional post-processing elements (e.g., based on T2-weighted series or morphology analysis) in the future.

[123I]IBZM SPECT for imaging of striatal D2 dopamine receptors in 56 schizophrenic patients taking various neuroleptics.

OBJECTIVE: The purpose of this study was to compare the binding of various typical and atypical neuroleptics to striatal D2 dopamine receptors in schizophrenic patients. METHOD: Fifty-six inpatients with schizophrenia, including 14 with schizoaffective disorder and one with schizophreniform disorder, were evaluated. Fourteen patients were neuroleptic free. Single photon emission computed tomography (SPECT) was performed 90 minutes after intravenous injection of [123I]benzamide ([123I]IBZM). Subsequent semiquantitative analysis of D2 receptor binding was done with the use of the basal ganglia (striatum)/frontal cortex (BG/FC) ratio of activity. Clinical symptoms were rated with the Positive and Negative Syndrome Scale and the Hamilton Depression Rating Scale. RESULTS: The BG/FC ratios in patients taking typical neuroleptics were significantly lower than those in the neuroleptic-free subjects but not lower than those in the patients taking atypical neuroleptics (clozapine, remoxipride). For atypical antipsychotics, a dose-dependent relationship with striatal D2 receptor binding could not be demonstrated. BG/FC ratios were not significantly correlated with clinical symptoms or with duration of illness. CONCLUSIONS: The results indicate that [123I]IBZM SPECT is useful for semiquantitative imaging of striatal D2 dopamine receptors and for estimating their blockade by neuroleptics. Thus, it may improve drug monitoring in psychiatric patients. Furthermore, the findings suggest a complex relationship between the antipsychotic effect of atypical neuroleptics and D2 receptor blockade.

Disseminated bone marrow metastases from primary breast cancer: detection and follow-up by radioimmune bone marrow scintigraphy.

Bone scintigraphy of a 40-yr-old patient suffering from primary breast cancer suggested the possibility of diffuse metastases. Bone marrow scintigraphy using 99mTc-labeled monoclonal antibodies (BW 250/183) demonstrated diffuse destruction of bone marrow due to metastatic disease and consecutive bone marrow extension. Bone marrow scintigraphy was highly sensitive in detecting progression of disease in this asymptomatic patient.

Cerebral blood flow in Sneddon syndrome.

Sneddon syndrome is defined as a clinical entity consisting of livedo racemosa generalisata (LRG) and cerebrovascular lesions, which often lead to physical and mental handicaps. Four patients with LRG and the suspected diagnosis of Sneddon syndrome had HMPAO-SPECT studies. The patients underwent CT and/or MR brain imaging and three patients had Duplex sonography of the cerebral arteries (TCD). Brain SPECT was abnormal in all patients, whereas CT/MRI revealed a cerebral lesion in only one patient and all TCD studies were normal. HMPAO-SPECT is valuable in detecting disturbed regional cerebral blood flow before irreversible ischemic insults occur, thus allowing the diagnosis of Sneddon syndrome at an early stage.

Dynamic phosphorus-31 magnetic resonance spectroscopy in arterial occlusive disease: effects of vascular therapy on spectroscopic results.

RATIONALE AND OBJECTIVES: The aim of the authors' prospective study was to explore therapy-induced changes of muscular metabolism in arterial occlusive disease (AOD). MATERIALS: Before and after vascular therapy, respectively, 31 patients with AOD were examined by dynamic phosphorus-31 (31P) magnetic resonance spectroscopy (MRS) at 1.5 T; in the magnet, the quadriceps muscle was stressed by an isometric and an isotonic form of exercise until exhaustion, respectively. Twenty-three patients were treated by standardized percutaneous transluminal angioplasty; eight patients underwent a vascular operation. RESULTS: Vascular therapy induced a marked improvement of clinical and angiographic results. At the same work load, exercise-induced metabolic changes of the quadriceps muscle were significantly less pronounced after the vascular therapy: maxima of the ratio inorganic phosphate (Pi)/phosphocreatine (PCr) (isometric exercise: 0.34 [after therapy] versus 0.44 [before therapy]; isotonic exercise: 0.36 [after therapy] versus 0.51 [before therapy]) as well as minima of pH (isometric exercise: 7.00 [after therapy] versus 6.93 [before therapy]; isotonic exercise: 7.00 [after therapy] versus 6.93 [before therapy]). In relation to maximal values of Pi/PCr, the extent of acidosis was smaller after vascular therapy, resulting in a flatter slope of the regression line between these parameters (b = -0.24 +/- 0.10 versus b = -0.31 +/- 0.09). After both of the exercises, time of half recovery of Pi/PCr was significantly shorter after vascular therapy (isometric exercise: 43 seconds [after therapy] versus 83 seconds [before therapy]; isotonic exercise: 42 seconds [after therapy] versus 57 seconds [before therapy]). CONCLUSIONS: After effective vascular therapy, minor exercise-induced metabolic changes (increased "work/energy cost-index"), a decreased contribution of anaerobic glycolysis to total adenosine triphosphate production as well as a markedly increased recovery rate of Pi/PCr are unequivocal spectroscopic proofs of an improved oxidative metabolism of muscle cells because of increased tissue perfusion.

Improved artificial neural networks in prediction of malignancy of lesions in contrast-enhanced MR-mammography.

The aim of this study was to evaluate the capability of improved artificial neural networks (ANN) and additional novel training methods in distinguishing between benign and malignant breast lesions in contrast-enhanced magnetic resonance-mammography (MRM). A total of 604 histologically proven cases of contrast-enhanced lesions of the female breast at MRI were analyzed. Morphological, dynamic and clinical parameters were collected and stored in a database. The data set was divided into several groups using random or experimental methods [Training & Testing (T&T) algorithm] to train and test different ANNs. An additional novel computer program for input variable selection was applied. Sensitivity and specificity were calculated and compared with a statistical method and an expert radiologist. After optimization of the distribution of cases among the training and testing sets by the T & T algorithm and the reduction of input variables by the Input Selection procedure a highly sophisticated ANN achieved a sensitivity of 93.6% and a specificity of 91.9% in predicting malignancy of lesions within an independent prediction sample set. The best statistical method reached a sensitivity of 90.5% and a specificity of 68.9%. An expert radiologist performed better than the statistical method but worse than the ANN (sensitivity 92.1%, specificity 85.6%). Features extracted out of dynamic contrast-enhanced MRM and additional clinical data can be successfully analyzed by advanced ANNs. The quality of the resulting network strongly depends on the training methods, which are improved by the use of novel training tools. The best results of an improved ANN outperform expert radiologists.

[Color-coded volume reconstruction for 3-dimensional presentation of CT data]. / Farbkodierte Volumen-Rekonstruktionen zur dreidimensionalen Darstellung von CT-Daten.

PURPOSE: To evaluate a technique of colored three-dimensional reconstructions without segmentation. MATERIAL AND METHODS: Color-coded volume rendered images were reconstructed from the volume data of 25 thoracic, abdominal, musculoskeletal, and vascular helical CT scans using commercial software. The CT volume rendered voxels were encoded with color in the following manner. Opacity, hue, lightness, and chroma were assigned to each of four classes defined by CT number. Color-coded reconstructions were compared to the corresponding grey-scale coded reconstructions. RESULTS: Color coded volume rendering enabled realistic visualisation of pathologic findings when there was sufficient difference in CT density. Segmentation was necessary in some cases to demonstrate small details in a complex volume. CONCLUSION: Color coded volume rendering allowed lifelike visualisation of CT volumes without the need of segmentation in most cases.

[3D CT of fractures: comparison of volume and surface reconstruction]. / 3D-CT von Frakturen: Vergleich von Volumen- und Oberflächen-Rekonstruktionen.

PURPOSE: The comparison of volume rendering (VR) and surface rendering (SSD) for demonstrating fractures from spiral-CT data. MATERIALS AND METHODS: Standardized VR and SSD projections were produced from 50 spiral CT scans of 50 consecutive patients with fractures. Appropriate multiplanar reformattings (MPR) were used as the standard. RESULTS: SSD provided sufficient information in 31/50 cases. Results of VR were not significantly different (33/50). VR was superior in demonstrating 6/7 craniofacial fractures and 3/3 calcaneal fractures. SSD was superior for visualizing 2/3 shoulder fractures and 2/2 elbow fractures. CONCLUSION: VR is a flexible technique for the depiction of fractures and the assessment of spongiosa and articular surfaces at one setting. SSD is superior in the delineation of small dislocated fragments.

[Sonography in suspected appendicitis: a decisive factor in diagnosis and therapy? Results of a prospective study of 669 patients]. / Sonographie bei Verdacht auf Appendizitis: Wende in Diagnostik und Therapie? Ergebnisse einer prospektiven Studie an 669 Patienten.

The appendectomy-rate in the Federal Republic of Germany is decreasing. German surgeons have begun to refuse appendectomy if there are no signs of acute inflammation. Preoperative assessment of patients with right lower quadrant pain has acquired new significance. The authors report on 2 years of experience with routine use of high-resolution ultrasonography in 669 cases of suspected acute appendicitis. Only 101 patients (= 15.1%) turned out to be suffering from acute appendicitis. Ultrasonography evaluation was found to have a sensitivity of 84.2%, a specificity of 96.8% and an overall accuracy of 94.9%. Ultrasonography was also useful in detecting mimicking diseases of acute appendicitis. Sonography should help to rule out severe disease in the frequent cases of functional abdominal pain.

[Cardiac MRI in suspected myocarditis]. / MRT des Herzens bei Verdacht auf Myokarditis.

PURPOSE: To evaluate the potential of ECG-gated breath-hold MRI in diagnosing acute myocarditis. MATERIAL AND METHODS: Cardiac MRI was performed on 21 consecutive patients with suspected myocarditis. ECG-gated breath-hold T2-weighted images with fat suppression were acquired in 3 standard views. T1-weighted imaging (FLASH) was performed 10 min after IV administration of Gd-DTPA. Laboratory data included creatine kinase, troponin T and serological tests, ECG findings and echocardiography. Imaging findings were retrospectively compared to the discharge diagnoses. Signal alterations were semiquantitatively classified. RESULTS: Acute myocarditis was diagnosed in 9 patients and cardiac sarcoidosis in 2 patients. Late enhancement was observed in 4 patients with acute myocarditis and in both patients with cardiac sarcoidosis. Semiquantitative evaluation revealed 9 true positive, 9 true negative, 1 false positive and 2 false negative results. CONCLUSION: Cardiac MRI has the potential to detect acute myocarditis and to diagnose cardiac sarcoidosis. Late enhancement of Gd-DTPA can be found in both viral myocarditis and cardiac sarcoidosis.

[Popliteal aneurysms: clinical aspects and diagnosis]. / Das Popliteaaneurysma: Klinik und Diagnostik.

PURPOSE: To identify clinical and radiological features allowing an early diagnosis of popliteal aneurysms. MATERIAL AND METHODS: History, clinical features and radiological findings of 23 patients with 37 aneurysms were reviewed. RESULTS: 14 patients presented with a history of a sudden onset of rest pain localised in the calf or foot. Arteriography found popliteal artery occlusion in 12 of them. Amputation was necessary in one patient in spite of immediate diagnosis and therapy. In two cases embolisation of the tibial vessels caused intermittent claudication. In at least 7 patients the underlying disease was not suspected until arteriography was performed. In 16/23 patients the presence of thrombus prevented direct visualisation of the aneurysm and there were only secondary angiographic signs of the underlying condition. Thus, arteriography may fail to diagnose popliteal aneurysms. In 21/22 cases colour Doppler sonography was quick and accurate in the assessment of patent and thrombosed aneurysms. CONCLUSION: In any patient with ischaemic symptoms of the lower extremity a thorough palpation of the popliteal fossa should be performed. In patients with a prominent popliteal pulse, in pulseless popliteal tumours and in patients arteriographically shown to have popliteal artery occlusion, a sonographic study of both popliteal fossae should be performed.

[CT angiography versus intra-arterial DSA in abdominal aortic aneurysms]. / CT-Angiographie versus intraarterielle DSA bei Bauchaortenaneurysmen.

PURPOSE: To evaluate if CT angiography is able to image all features necessary for the preoperative planning of abdominal aortic aneurysms (accessory renal arteries, stenoses or occlusions of renal and iliac arteries, patency of inferior mesenteric artery). METHODS: CT angiography and DSA were performed on 27 patients with abdominal aortic aneurysms. CT angiography was performed using a protocol that covered the abdominal aorta and the pelvic arteries with a single spiral acquisition (contrast dose: 150 ml, collimation: 5 mm, table feed: 7.5 mm/s, increment of reconstruction: 2 mm). Maximum intensity projections (MIP) and axial scans were compared with the results of intraarterial DSA. RESULTS: Using axial scans and subvolume MIP, CTA accurately defined 7/8 accessory renal arteries, 13/13 occlusions and 9/12 high grade stenoses of renal and pelvic arteries. High-grade stenoses of the iliac arteries were underestimated in two cases and overlooked in one case. CT angiography was superior to DSA in imaging the inferior mesenteric artery. CT angiography precisely diagnosed 33 aneurysms of the iliac, renal and coeliac arteries. CONCLUSION: CT angiography using a single administration of intravenous contrast may replace preoperative DSA in most cases of abdominal aortic aneurysm.

[Segmental anatomy of the liver in computed tomography: do we localize the lesion accurately?]. / Segmentanatomie der Leber in der Computertomographie: Lokalisieren wir die Läsionen richtig?

PURPOSE: To evaluate if Couinaud's model using the planes of the major veins is an adequate tool for the presurgical localization of focal liver lesions. METHODS: Biphasic helical CT scans were performed on patients evaluated for liver resection using an increased IV bolus of contrast medium (180 ml lopamidol) and 2 mm image reconstruction increments. During the first evaluation, all liver lesions were localized in the conventional way using the planes of the 3 major hepatic veins and the portal trunks as segmental boundaries. In a second review, all lesions were attributed to the nearest peripheral portal branches. The path and the segmental attribution of the portal branches were analysed. Evaluations were performed using an interactive cine mode as well as three-dimensional reconstructions. RESULTS: 20 of 126 (16%) liver lesions had a different segmental location if the individual anatomy of the peripheral portal branch was used instead of the conventional technique. These different locations were due to the path of the portal trunks or the path of the peripheral portal branches crossing the planes of the major hepatic veins. CONCLUSION: The segmental anatomy of the liver using the planes of hepatic veins and portal trunks according to Couinaud is not an accurate tool for the presurgical localization of liver lesions in many cases.

[MR tomography and bone marrow scintigraphy in the screening of skeletal metastases in patients with breast carcinoma]. / MRT und Knochenmarkszintigraphie im Screening von Skelettmetastasen bei Patientinnen mit Mammakarzinom.

46 patients with recently diagnosed carcinoma of the breast were included in a prospective comparative study of MRI and bone marrow scintigraphy. The aim of the study was to compare these procedures within a histologically unified patient collective. It was shown that MRI was superior to bone marrow scintigraphy in respect of sensitivity (92% vs 58%) and specificity (97% vs. 85%), although only about three quarters of the marrow spaces are examined by MRI screening. Bone marrow scintigraphy suffered particularly from a relatively high number of false positive findings (haemangiomas, degenerative changes). MRI remains the method of choice for investigating the bone marrow.

[CT angiography in arterial occlusive disease: comparison of 3 rendering techniques]. / CT-Angiographie bei arterieller Verschlusskrankheit: Vergleich von 3 Rekonstruktionsverfahren.

PURPOSE: To evaluate different rendering techniques of CT data for the assessment of long vessel segments in peripheral vascular occlusive disease. MATERIAL AND METHODS: 40 CT angiograms (aortoiliac: n = 20, leg arteries: n = 20) were viewed using three different rendering techniques: 1, maximum intensity projection (MIP); 2, volume rendering (VR); 3, shaded surface display (SSD). CT angiograms were obtained in 6 or 8 projections. Axial cross-section images were analysed using an interactive cine mode. Intraarterial DSA was the standard in all cases. RESULTS: The sensitivities for the diagnosis of occlusive disease were 100% (cross-section images), 94% (MIP), 91% (VR) and 93% (SSD). The specificities were 100%, 99%, 99% and 99%, respectively. For the accurate grading of high-grade (> 75%) stenoses, the sensitivities were 85% (cross-section images), 62% (MIP), 44% (VR) and 35% (SSD). Specificity was 99% for all techniques. CONCLUSIONS: CTA is accurate in occlusive disease. Interactive viewing of cross-section images is the most accurate technique. MIP is superior to VR in the imaging of high-grade stenoses because contrast-to-noise ratio is high and thresholding is not necessary.

[Automatic classification of liver segments according to Couinaud: development of a new algorithm and evaluation spiral CT data]. / Automatische Klassifikation der Lebersegmente nach Couinaud: Entwicklung eines neuen Algorithmus und Evaluierung an Spiral-CT-Datensätzen.

PURPOSE: To develop a software tool that analyzes the anatomy of the portal vein branches and assigns segmental and subsegmental branches according to Couinaud's classification system and to evaluate its accuracy. MATERIALS AND METHODS: The algorithm was developed in C++ on a PC. The algorithm recognizes the three major branching patterns of the portal vein. Segmental and subsegmental branches are assigned to 8 segments following Couinaud and encoded by 8 colors. The software was evaluated using CT data sets of 39 patients. After the individual segmental anatomy of each patient was determined by an experienced radiologist, automatic classification was performed and the results were compared on a branch by branch basis. RESULTS: The numbering was accurate according to Couinaud's system in 358 of 409 segmental and subsegmental branches (88 %). The assignment failed in 51 of 409 branches due to unexpected anatomy or software problems. CONCLUSION: Automatic classification of portal vein branches and their appendant parenchyma is possible. The automatic designation of liver segments enables the three-dimensional visualization of the segmental anatomy. In the future, automatic analysis might facilitate the reporting and communication of CT findings.

[Triphasic spiral CT in the diagnosis of liver diseases: comparison with CT arteriography and CT arterio-portography]. / Drei-Phasen-Spiral-CT in der Diagnostik von Lebererkrankungen: Vergleich mit CT-Arteriographie und -Arterioportographie.

PURPOSE: Assessment of the diagnostic efficacy of triphasic spiral-CT scanning (TPS-CT) for liver disease evaluation. CT arteriography (CTA) and CT arterio-portography (CTAP) were used as reference, methods which together have the highest sensitivity for detecting tumours and the perfusion conditions of the liver. MATERIAL AND METHODS: 50 TPS-CT and CTA/CTPA were performed in 49 patients. After an initial examination without enhancement the first scan was initiated 15-25s after the peripheral bolus injection of contrast medium, the second after an interscan delay of 20-25s. By this means the liver was imaged in different phases of perfusion. In the course of the CTA/CTPA-exam the imaging was carried out after selective, intraarterial application of contrast agent. RESULTS: The differentiation of the perfusion phases succeeded in 90% of the patients. When compared with standard CT, which images only the portal venous phase, the new technique, which additionally shows the arterial perfusion, accomplished an increase in sensitivity for hypervascular lesions (51% vs. 60%). Yet in comparison with CTA/CTPA fewer lesions could be detected (87 vs. 138). Furthermore, by documenting the contrast agent kinetics, characterisation of the lesion was also facilitated. CONCLUSION: DPS-CT is a valuable additional tool for imaging the liver, even if the information yield is less when compared to CTA/CTPA.

[HMPAO-SPECT in Alzheimer-type dementia and major depression with memory disorders]. / HMPAO-SPECT bei Demenz vom Alzheimer-Typ und Major Depression mit mnestischen Störungen.

The aim of the present study was to see whether HMPAO-SPECT may contribute to the differentiation between dementia of the Alzheimer type (DAT) and major depression (MD). The results in 77 patients with memory impairment were evaluated. 48 patients suffered from DAT and 29 from MD. Initially, the defects in SPECT imaging were attributed to a cerebral region and the degree of decrease was evaluated (-1/-2/-3). Thereafter, the results were classified by 7 categories. In some of these categories an accumulation of cases of either DAT or MD was found. 35% of the patients suffering from DAT had bilateral defects with distinct (> -1) parietal/parietotemporal hypoperfusions, but no patient with MD showed this perfusion pattern. 62% of the patients with MD had unilateral defects but only 31% of the patients with DAT. The present study demonstrates that only 35% of all patients suffering from DAT show a perfusion pattern, thought earlier as "pathognomonic" for this disease. This perfusion pattern--if it exists--may be used as a safe criterion to exclude MD. Beyond that no clearcut ("specific") perfusion pattern may be recognized but unilateral defects point to MD.