Spatial proteogenomics reveals distinct and evolutionarily conserved hepatic macrophage niches

The liver is the largest solid organ in the body, yet it remains incompletely characterized. Here we present a spatial proteogenomic atlas of the healthy and obese human and murine liver combining single-cell CITE-seq, single-nuclei sequencing, spatial transcriptomics, and spatial proteomics. By integrating these multi-omic datasets, we provide validated strategies to reliably discriminate and localize all hepatic cells, including a population of lipid-associated macrophages (LAMs) at the bile ducts. We then align this atlas across seven species, revealing the conserved program of bona fide Kupffer cells and LAMs. We also uncover the respective spatially resolved cellular niches of these macrophages and the microenvironmental circuits driving their unique transcriptomic identities. We demonstrate that LAMs are induced by local lipid exposure, leading to their induction in steatotic regions of the murine and human liver, while Kupffer cell development crucially depends on their cross-talk with hepatic stellate cells via the evolutionarily conserved ALK1-BMP9/10 axis.

Hepatic Macrophage Responses in Inflammation, a Function of Plasticity, Heterogeneity or Both?

With the increasing availability and accessibility of single cell technologies, much attention has been given to delineating the specific populations of cells present in any given tissue. In recent years, hepatic macrophage heterogeneity has also begun to be examined using these strategies. While previously any macrophage in the liver was considered to be a Kupffer cell (KC), several studies have recently revealed the presence of distinct subsets of hepatic macrophages, including those distinct from KCs both under homeostatic and non-homeostatic conditions. This heterogeneity has brought the concept of macrophage plasticity into question. Are KCs really as plastic as once thought, being capable of responding efficiently and specifically to any given stimuli? Or are the differential responses observed from hepatic macrophages in distinct settings due to the presence of multiple subsets of these cells? With these questions in mind, here we examine what is currently understood regarding hepatic macrophage heterogeneity in mouse and human and examine the role of heterogeneity vs plasticity in regards to hepatic macrophage responses in settings of both pathogen-induced and sterile inflammation.

Germ-Free Mice Exhibit Mast Cells With Impaired Functionality and Gut Homing and Do Not Develop Food Allergy

Background: Mucosal mast cells (MC) are key players in IgE-mediated food allergy (FA). The evidence on the interaction between gut microbiota, MC and susceptibility to FA is contradictory.

Objective: We tested the hypothesis that commensal bacteria are essential for MC migration to the gut and their maturation impacting the susceptibility to FA.

Methods: The development and severity of FA symptoms was studied in sensitized germ-free (GF), conventional (CV), and mice mono-colonized with L. plantarum WCFS1 or co-housed with CV mice. MC were phenotypically and functionally characterized.

Results: Systemic sensitization and oral challenge of GF mice with ovalbumin led to increased levels of specific IgE in serum compared to CV mice. Remarkably, despite the high levels of sensitization, GF mice did not develop diarrhea or anaphylactic hypothermia, common symptoms of FA. In the gut, GF mice expressed low levels of the MC tissue-homing markers CXCL1 and CXCL2, and harbored fewer MC which exhibited lower levels of MC protease-1 after challenge. Additionally, MC in GF mice were less mature as confirmed by flow-cytometry and their functionality was impaired as shown by reduced edema formation after injection of degranulation-provoking compound 48/80. Co-housing of GF mice with CV mice fully restored their susceptibility to develop FA. However, this did not occur when mice were mono-colonized with L. plantarum.

Conclusion: Our results demonstrate that microbiota-induced maturation and gut-homing of MC is a critical step for the development of symptoms of experimental FA. This new mechanistic insight into microbiota-MC-FA axis can be exploited in the prevention and treatment of FA in humans.

Detection of coronary artery disease in postmenopausal women: the significance of integrated stress imaging tests in a 4-year prognostic study

BACKGROUND

The present prospective study investigated whether a combined approach integrating two different stress imaging modalities may improve the diagnostic accuracy and prognostic impact of non-invasive coronary artery disease (CAD) tests in postmenopausal women. In women non-invasive tests for detecting CAD are less accurate than in men, leading to a high proportion of unnecessary coronary angiographies (CAs).

METHODS

424 consecutive postmenopausal women (mean 61 ± 7 years, mean Reynolds Risk Score 13 ± 3 %) with symptoms suggestive of CAD were prospectively included and followed up for 4 ± 1 years. Each patient underwent CA, stress cardiovascular magnetic resonance (CMR) by adenosine, dobutamine stress echocardiography (DSE) and single-photon emission computed tomography (SPECT) within 7 ± 3 days.

RESULTS

Anatomically obstructive coronary artery disease (≥50 % diameter stenosis) was present in 157 women (37 %). The combination of two stress imaging modalities significantly increased the positive predictive values (PPV) to 90 ± 3, 88 ± 3 and 87 ± 2 % for CMR/DSE, DSE/SPECT and CMR/SPECT, respectively. For patients with negative combined test results, the survival analysis showed a 4-year cumulative event-free survival rate of 96-97 % for all combinations. This new approach is cost effective due to the resulting reduction in unnecessary CAs (with potential side effects and corresponding therapies) as well as reducing hospitalization time.

CONCLUSIONS

In symptomatic postmenopausal women, combination of two negative stress imaging results significantly increases the PPV for detection of CAD and excludes future cardiovascular events with high accuracy. This approach may be applied to improve the prognostic precision of non-invasive CAD tests and to avoid unnecessary CAs.

Glutathione-S-transferase: a minor allergen in birch pollen due to limited release from hydrated pollen

BACKGROUND

Recently, a protein homologous to glutathione-S-transferases (GST) was detected in prominent amounts in birch pollen by proteomic profiling. As members of the GST family are relevant allergens in mites, cockroach and fungi we investigated the allergenic relevance of GST from birch (bGST).

METHODOLOGY

bGST was expressed in Escherichia coli, purified and characterized by mass spectrometry. Sera from 217 birch pollen-allergic patients were tested for IgE-reactivity to bGST by ELISA. The mediator-releasing activity of bGST was analysed with IgE-loaded rat basophil leukaemia cells (RBL) expressing human FcεRI. BALB/c mice were immunized with bGST or Bet v 1. Antibody and T cell responses to either protein were assessed. IgE-cross-reactivity between bGST with GST from house dust mite, Der p 8, was studied with murine and human sera in ELISA. The release kinetics of bGST and Bet v 1 from birch pollen were assessed in water, simulated lung fluid, 0.9% NaCl and PBS. Eluted proteins were quantified by ELISA and analysed by immunoblotting.

PRINCIPLE FINDINGS

Only 13% of 217 birch pollen-allergic patients showed IgE-reactivity to bGST. In RBL assays bGST induced mediator release. Immunization of mice with bGST induced specific IgE and a Th2-dominated cellular immune response comparably to immunization with Bet v 1. bGST did not cross-react with Der p 8. In contrast to Bet v 1, only low amounts of bGST were released from pollen grains upon incubation in water and the different physiological solutions.

CONCLUSION/SIGNIFICANCE

Although bGST is abundant in birch pollen, immunogenic in mice and able to induce mediator release from effector cells passively loaded with specific IgE, it is a minor allergen for birch pollen-allergic patients. We refer this discrepancy to its limited release from hydrated pollen. Hence, bGST is an example demonstrating that allergenicity depends mainly on rapid elution from airborne particles.

Layer-specific analysis of myocardial deformation for assessment of infarct transmurality: comparison of strain-encoded cardiovascular magnetic resonance with 2D speckle tracking echocardiography

AIMS

Separate analysis of endocardial and epicardial myocardial layer deformation has become possible using strain-encoded cardiovascular magnetic resonance (SENC) and 2D-dimensional speckle tracking echocardiography (Echo). This study evaluated and compared both modalities for the assessment of infarct transmurality as defined by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR).

METHODS AND RESULTS

In 29 patients (age 62.4 ± 11.7 years, 23 male) with ischaemic cardiomyopathy, SENC using 1.5 T CMR and Echo were performed. Peak circumferential systolic strain of the endocardial and the epicardial layer of 304 myocardial segments was assessed by SENC and by Echo. The segmental transmurality of myocardial infarction was determined as relative amount of LGE (0%: no infarction; 1-50%: non-transmural infarction; 51-100%: transmural infarction). Endocardial and epicardial strain defined by SENC and by Echo differed significantly between segments of different infarct transmurality determined by CMR. Endocardial layer circumferential strain analysis by Echo and by SENC allowed distinction of segments with non-transmural infarction from non-infarcted segments with similar accuracy [area under the curve (AUC) 0.699 vs. 0.649, respectively, P = 0.239]. Epicardial layer circumferential strain analysis by Echo and by SENC allowed distinction of transmural from non-transmural myocardial infarction defined by LGE CMR with similar accuracy (AUC 0.721 vs. 0.664, respectively, P = 0.401). Endocardial strain by SENC correlated moderately with endocardial strain by Echo (r = 0.50; standard error of estimate = 5.2%).

CONCLUSION

Layer-specific analysis of myocardial deformation by Echo and by SENC allows discrimination between different transmurality categories of myocardial infarction with similar accuracy. However, accuracy of both methods is non-optimal, indicating that further tools for improvement should be evaluated in the future.

Quantitative analysis of endocardial and epicardial left ventricular myocardial deformation-comparison of strain-encoded cardiac magnetic resonance imaging with two-dimensional speckle-tracking echocardiography

BACKGROUND

Quantitative analysis of segmental myocardial deformation of different myocardial layers has become possible using strain-encoded cardiac magnetic resonance imaging (SENC) and speckle-tracking echocardiography (STE). We evaluated and compared the quantitative analysis of myocardial deformation using SENC and STE.

METHODS

In 44 patients (age 61 ± 13 years, 34 men), SENC by cardiac magnetic resonance imaging using a 1.5-Tesla whole-body scanner and two-dimensional STE were performed prospectively. Quantitative layer-specific analysis of segmental left ventricular function was performed to determine the peak circumferential and peak longitudinal systolic strain values using SENC and STE of an endocardial and epicardial myocardial layer. In addition, segmental function was defined as normokinetic, hypokinetic, or akinetic by visual analysis of the magnetic resonance imaging cine sequences.

RESULTS

The endocardial and epicardial strain defined by SENC or STE differed significantly between the visually defined segmental function states. The correlation of the peak circumferential endocardial strain by SENC versus STE (intraclass correlation coefficient [ICC] 0.493, 95% CI 0.358-0.597) tended to be better than the correlation of the circumferential epicardial strain using both methods (ICC 0.321, 95% CI 0.238-0.399). The correlation of the peak longitudinal endocardial strain by SENC and STE was similar (ICC 0.472, 95% CI 0.398-0.541), in contrast to the longitudinal epicardial strain analysis by both techniques (ICC 0.554, 95% CI 0.417-0.655). Circumferential strain analysis by STE allowed better distinction of the hypokinetic or akinetic segments from the normokinetic segments than did the circumferential strain analysis by SENC of the endocardial layer (area under the receiver operating characteristic curve [AUC ROC] 0.946 vs 0.884; P < .001) or epicardial layer (AUC ROC 0.884 vs 0.782; P < .001). Longitudinal strain analysis using STE and SENC of the endocardial layer (AUC ROC 0.851 vs 0.839; P = .5838) and epicardial layer (AUC ROC 0.849 vs 0.833; P = .4321) had similar diagnostic value for identifying the presence of hypokinetic and akinetic segments.

CONCLUSIONS

Quantitative analysis of segmental deformation by SENC and STE allowed accurate distinction of myocardial segments with different functional states. Circumferential endocardial strain analysis by STE allowed the best distinction of segments with impaired function from the normokinetic segments.

Cardiogenic shock due to tachycardiomyopathy after heart transplantation: successful treatment with ivabradine

Tachycardia-induced cardiomyopathy refers to an impairment in left-ventricular function due to chronic or prolonged tachycardia. We describe a heart transplant patient who developed cardiogenic shock due to tachycardia-induced cardiomyopathy. Low-output failure was further aggravated by administration of a short-acting beta-blocker during invasive hemodynamic monitoring. In contrast, heart rate control by administration of increasing doses of ivabradine supported recovery from cardiogenic shock and led to an improvement in the patient's clinical condition as well as left-ventricular function during follow-up.

Contrast-enhanced power Doppler sonography: improved detection of characteristic flow patterns in focal liver lesions

PURPOSE

The aim of this study was to evaluate whether intravenous injection of an ultrasound contrast agent aids in the visualization of focal liver lesions on power Doppler images.

METHODS

Fifty patients with focal liver lesions were studied by B-mode and power Doppler sonography before and after intravenous injection of the contrast agent Levovist (galactose-based microbubbles; 10 ml of a concentration of 300 mg/ml). Thirty-two patients had malignant liver lesions (19 metastases, 12 hepatocellular carcinomas, 1 cholangiocellular carcinoma), while 18 had benign lesions (12 hemangiomas, 2 focal nodular hyperplasias, 4 others).

RESULTS

After contrast medium injection, the number of lesions with no intralesional flow dropped from 18 to 9. Flow signal intensity was rated subjectively as marked on contrast-enhanced images in 17 patients; only 4 patients had marked flow on precontrast images. On precontrast studies, central flow in 10 lesions and peripheral flow in 29 lesions could be observed. After enhancement, the numbers increased to 18 and 34 lesions, respectively.

CONCLUSIONS

On power Doppler images, a greater number of intratumoral vessels are seen in focal liver lesions after contrast medium administration.

[Radiotherapy of humero-scapular periarthritis using ultra-hard photons. Evaluation by MRI findings]

PURPOSE

Evaluation of MRI in radiotherapy of humeroscapular periarthritis.

PATIENTS AND METHODS

Seventy-seven patients with humeroscapular periarthritis prospectively underwent MRI before radiotherapy.

RESULTS

Six months after radiotherapy, 34% of the patients had achieved complete pain relief, 35% major pain relief. Twenty percent had only slight improvement and 12% no improvement. Positive correlation of radiotherapy outcome and MRI findings could be shown for acute tendinitis, erosions, and complete and incomplete ruptures of the supraspinatus tendon.

CONCLUSIONS

Radiotherapy is highly effective in the treatment of humeroscapular periarthritis. The indication can be improved using MRI.

[Multi-project angiography in the imaging of cerebral aneurysm]

In spite of procedures such as CT angiography, MR angiography, and rotation angiography, panangiography is still indispensable in therapeutic planning for cerebral aneurysms. It is the only method that provides exact details about the size, anatomic localization, and multiplicity of aneurysms as well as relation to surrounding vessels, the presence of an aneurysmal neck, and for the evaluation of the collateral circulation required to answer the question if endovascular therapy is possible. In addition, panangiography still exhibits the highest selectivity in the detection of cerebral aneurysms.

Septum orbitale: high-resolution MR in orbital anatomy

PURPOSE

The purpose of this study was to ascertain whether MR imaging, with the use of a surface coil, can accurately show small intraorbital structures; in particular, the septum orbitale.

METHODS

Examinations of 26 patients who underwent unilateral orbital high-resolution MR imaging for different indications were evaluated to differentiate the septum orbitale from related structures, such as the aponeurosis of the levator palpebrae, the superior tarsal (Müller's) muscle, and the superior orbital (Whitnall's) ligament.

RESULTS

A subtle differentiation of the septum orbitale was obtained in 23 patients (88%) and of the levator aponeurosis and Müller's muscle in 24 patients (92%). The orbicularis oculi muscle and the submuscular fibroadipose tissue were reliably identified in all patients.

CONCLUSIONS

High-resolution MR imaging is suitable for differentiating small intraorbital structures. Nevertheless, an exact depiction of the septum orbitale remains very much dependent on the cooperation of the patient. The site of orbital disease can be determined precisely and in a noninvasive manner in relation to the septum orbitale.

Computed tomography with iodine-free contrast media

The purpose of this work was to evaluate the enhancement of different concentrations of gadolinium (Gd), ytterbium (Yb) and iodine in vitro and in vivo. Comparisons were made of the enhancement (HU) of Gd, Yb and iodine in concentrations ranging from 0.1 to 30 mg/ml. In vivo dynamic CT studies were performed in ten dogs with 0.5 M Gd, Yb and iodine. Time-density curves were achieved in aorta and liver. The in vitro studies confirmed a decrease in the enhancement in this order: Gd (120 kV) > Gd (137 kV) > Yb (120 kV) > Yb (137 kV) > iodine (120 kV) > iodine (137 kV). The specific enhancement of Gd was 40.8 (120 kV), of Yb 34.2 and of iodine 29.6 HU. The enhancement of the liver decreases from 21 HU (Gd) to 19 HU (Yb) and 12 HU (iodine). Gd and Yb achieved a higher aortal enhancement than iodine (190 vs 157 HU) All contrast media were well tolerated. Equimolar concentrations of Gd and Yb show a higher in vitro contrast and enhancement than iodine.

[Monostotic Paget's disease as differential diagnosis in osteolysis of the tibia]

Monostotic Paget's disease has a well known appearance in radiography. Only in exceptions is a further diagnostic procedure necessary. The value of MRI and scintigraphy is demonstrated on an osteolytic lesion of the tibia.

[Computerized tomography differentiation of hepatocellular carcinoma and cholangiocellular tumors]

20 patients with hepatocellular carcinomas (HCC) and 18 patients with tumours of the biliary passages and gallbladder (CAC)) were examined via angio-CT without table increment and via spiral CT. Evaluation of the time-density curve of angio-CT showed more rapid and greater enhancement in case of HCC, whereas CAC were characterised by slower and lesser contrast medium uptake than the surrounding hepatic tissue. Superior differential diagnostic information was obtained via angio-CT, whereas spiral CT yields the best information on extent and number of hepatic tumours.

A major renal artery aneurysm as the cause of a hydronephrosis with renovascular hypertension

In general, renal artery aneurysms occur very rarely. This study reports on a 9-cm renal artery aneurysm which was erroneously thought to be a renal cyst, and which, as a result of depression of the renal parenchym and the ureteropelvic junction, led to arterial hypertension and consecutive, reduced function hydronephrosis.

Value of magnetic resonance imaging in staging carcinomas of the oral cavity and oropharynx

The value of magnetic resonance imaging (MRI) in preoperative tumor (T) staging was assessed prospectively in 46 patients with malignant carcinomas of the oropharynx and oral cavity. In each case, the MRI findings were compared with the preoperative clinical and postoperative histopathologic findings. MRI showed an accuracy of 89% in identifying the T stage, as compared with the histopathologic result. The accuracy of the clinical examination was 78%. Compared with the clinical examination, MRI is particularly suited for differentiating T3/T4 and the larger T2 tumors. MRI tends to overinterpret the T stage when the neighboring tissues are inflamed or edematous, as it allows no demarcation between inflamed or edematous tissue and tumor. Moreover, normal oropharyngeal mucous membrane and intrinsic tongue muscle both absorb contrast medium. In the clinical examination, the T stage is often underestimated, as the depth of infiltration and bone involvement cannot always be determined with certainty. The ability of MRI to give an axial, coronal, and sagittal image allows an exact preoperative view of tumor spread and assessment of infiltration into adjacent structures.

[Color duplex sonography of liver transplantation. The vascular status]

The present study deals with the value of CDS in liver transplantation. Between September 1988 and October 1991 CDS of hepatic vessels was carried out in 194 liver transplants. Flow direction and flow velocity in the portal vein could be demonstrated in 97%. Measurement of flow velocity indicates the extent of portal hypertension; this can be confirmed by determining flow direction in the splenic and superior mesenteric veins. In 47 of 179 patients venous collaterals were demonstrated and in 15 of 179 patients there was retrograde flow in the splenic vein. In 95% of patients CDS indicated flow direction in the hepatic artery and in 93% in the hepatic veins. Thrombosis of liver vessels (portal and hepatic veins) was demonstrated in 11 out of 13 patients by means of CDS.

[Diffuse demineralization of the lumbar spine. Magnetic resonance tomography studies of osteoporosis and plasmacytoma]

On plain radiographs, diffuse infiltration of the spine in multiple myeloma may present as diffuse demineralization. Differentiation from osteoporotic changes is then difficult. 15 patients with multiple myeloma and 15 patients with osteoporosis were prospectively examined by MRI using plain and contrast enhanced gradient echo techniques. Examinations were evaluated for lesions and diagnosis was made by two independent observers. Contrast enhancement was visible in lesions detected in myeloma patients and in compression fractures. Fractures could be differentiated from malignant lesions by the fact that there was no multiplicity of enhancing lesions. Contrast enhanced opposed phase gradient echo sequences seem suited for the detection of vertebral involvement in myeloma.

[Feasibility of the differential diagnostic imaging of neck lymphomas]

In 51 patients with cervical swellings, pretherapeutic examinations by ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) were carried out for the confirmation of exclusion of cervical lymph node metastases. By use of the M/Q ratio and morphological criteria, it is possible with ultrasound to differentiate between relatively enlarged lymph modes and lymph node metastasis with a certainly of > 90%. This was only possible in CT after administration of contrast media and the success rate was lower (72%). Both by use of the M/Q ratio and contrast medium administration, MRI is able to distinguish between lymph node metastases and reactively altered lymph nodes. Differentiation between Hodgkin/non-Hodgkin lymphomas of the neck and reactively enlarged lymph nodes is also possible with the aid of the M/Q ratio. In such cases, sonography and MRI are superior to CT. A certain differentiation between lymph node metastases and Hodgkin/non-Hodgkin lymphomas is only possible in some cases. However, there are indicative criteria for differential diagnosis. A delineation between specific lymph node inflammations and glomus carotid tumors is also possible because of the differing take-up of contrast medium in CT and MRI and via doppler sonographic criteria.

[3-D spiral CT in diagnosis of orbital tumors with intracranial involvement]

3-D-Spiral-CT was performed in 2 patients with orbita tumors with intracranic portion. 3-D-CT is enable to visualize the bony connections and judgement of bony destruction. Because of methodical parameters 2D-CT must be the basic of clinical diagnostic.

[Bolus administration in spiral CT of the upper abdomen]

In 60 patients the density increases in the abdominal aorta and pancreas were examined quantitatively the visualisation of the arterial liver blood flow qualitatively in a test volume by means of spiral CT and a feed or speed differentiation of 10 mm/s for three different contrast medium boli. It was shown that during the entire study over 24 seconds the boli with 100 ml contrast medium at injection speeds of 3 ml/s and 50 ml contrast medium at 1.5 ml/s resulted in a continual density increase of the abdominal aorta from 221 to 265 Hounsfield Units (HU) or 161-167 HU, respectively. For measuring the abdominal aorta the bolus of 50 ml contrast medium at 3 ml/s was less suitable than the boli of 100 ml contrast medium with 3 ml/s and 50 ml with 3 ml/s because of the rapid in density from 250 to 118 HE. The bolus of 50 ml contrast medium and 3 ml/s, on the other hand, with 54 HU enhancement of the pancreas was approximately equal to the larger amount of contrast medium of 100 ml contrast medium and 3 ml/s with 56 HU, whereas 50 ml contrast medium and 1.5 ml/s with 46 HU was inferior. While all boli could sufficiently enhance the extrahepatic section of the hepatic artery, the larger amount of contrast of 100 ml proved to be superior to the other boli in the visualization of central intrahepatic vascular branches.

[CT contrast administration of iodine, gadolinium and ytterbium. In-vitro studies and animal experiments]

The absorption of the elements iodine, gadolinium and ytterbium in various dilutions was studied in relation to CT. Regression analysis and specific CT density measurements showed that absorption decreases from gadolinium to ytterbium and iodine. These results were confirmed by experiments using ten dogs. Boli of 0.5 molar gadolinium used for angio-CT without table movement showed the largest increase in density in the aorta and liver with an average of 190HU and 21HU respectively compared with iodine which gave 157HU and 12HU respectively. The animal experimental studies suggest that gadolinium and ytterbium are suitable contrast media for dynamic CT investigations.

[Lymph node metastases of the neck in unknown primary tumor: is there a differential imaging diagnosis?]

In 32 patients suffering from cervical lymph node metastases with an unknown primary tumour the pretherapeutic findings via sonography, CT and MR were compared and the post-therapy findings of tumour aftercare assessed. After an average follow-up period of 38 months the group of branchiogenic cervical cysts had no recurrence. In the group of 18 patients with more than one cervical lymph node metastasis without primary tumour, either the primary tumour or further lymph node metastases became manifest in 11 patients after an average follow-up period of 36 months. Imaging of the number of lymph node metastases and differentiation between malignant degenerated branchiogenic cysts and lymph node metastases without primary tumour is important for prognosis. A combination of findings from sonography, CT and MR enables performance of such differential diagnosis due to morphological aspects and aspects that are conditioned by the contrast medium.

[Catheter-induced vascular lesions: a comparison of the diagnostic value of Doppler color sonography versus angiography]

One hundred and thirty-two patients with suspected lesions of the femoral arteries following diagnostic and/or therapeutic cardiac catheterisation were studied by colour Doppler sonography (CDS) and digital subtraction angiography (DSA) and the results were compared. CDS was unable to demonstrate 5 out of 23 av fistulae. Intra-arterial DSA showed all av fistulae found at operation. CDS showed lower reliability (95%) than DSA (100%) for the demonstration of pseudoaneurysms. CDS can indicate hematoma and thrombi in pseudo-aneurysms and their exact extent is better shown by sonography. Arterial dissections (2 cases) and intra-luminal thromboses or occlusions of the femoral artery (4 cases) are shown equally well by the two procedures.

[The value of nuclear magnetic resonance tomography in tumor staging of laryngeal-/hypopharyngeal cancer]

Twenty-four patients with tumors of the larynx and hypopharynx were examined with magnetic resonance imaging (MRI) and laryngoscopy. The results of MRI and laryngoscopy were then correlated with the pathology reports. Diagnostic findings of 84% of the MRI studies correlated with the pathology report, while laryngoscopy provided exact classification in 79%. MRI tended to overestimate tumor size because edema or inflammatory reactions of surrounding tissues simulated tumors. However, normal mucosa also enhanced contrast medium, restricting the value of this technique. Laryngoscopy tended to underestimate tumor size, because deep extensions of tumor and cartilage involvement were difficult to detect. Nonetheless, the utility of MRI in obtaining axial, coronal and sagittal slices was found to facilitate the preoperative staging of tumor extensions.

[Computed tomography: the TNM staging of laryngeal carcinoma]

In 64 patients with malignant lesions of the larynx, CT and microlaryngoscopy (ML) were evaluated in terms of T-staging. Histological information was present in all cases following operation. CT showed an accuracy of 90% in T-staging. ML showed an accuracy of only 71% of correct T-staging. CT is superior to ML particularly in distinguishing between stages T3 and T4 and T1 and T2. CT tends to overestimate tumour stage whereas ML tends to underestimate it. CT was also compared with palpation and sonography as regards N-staging. In this respect sonography has the highest accuracy (94%) followed by palpation (76%) and CT (74%).

[Reactive enlargement of cervical lymph nodes and cervical lymph node metastases: sonography (M/Q quotient) and computed tomography]

Ranking of sonographic maximum/transverse diameter quotients was compared with the ranking of CT in respect of identification and exclusion of cervical lymph node metastases. Both sonography and CT are distinguished by a high degree of sensitivity in the imaging of cervical lymph node metastases. Sonography, with the assistance of the maximum/transverse diameter quotient, can differentiate between benign enlarged and non-enlarged lymph nodes on the one hand and cervical lymph node metastases on the other, with a safety of 95 per cent. CT can yield definite information regarding the tumour status only after contrast medium administration under the criteria of central hypodensity and peripheral marginal enhancement. CT is much less specific than the sonographic M/T quotient (66% vs 95%). Accuracy of sonography (94%) is clearly superior to that of CT (79%).

[The visualization of bony and vascular structures in digital subtraction images depending on the contribution of the anatomical background]

We examined the loss of contrast leaving a part of the anatomic background in digital subtraction angiography by visual analysis and densitometry. We observed a greater loss of the quality at the representation of the bone below than above an amount of anatomic background of 60%. The loss of quality at the representation of the vessels decreases more above than below an anatomical background of 45%. We think that, depending on the clinical problem, an anatomical background between 15 and 30% should be left.

[The value of radioimmunoscintigraphy compared to computed tomography in the diagnosis and relapse diagnosis of colorectal tumors]

Radioimmunoscintigraphy (= RIS, scintigraphic "specific" imaging of benign and malignant diseases by means of radioactively marked monoclonal antibodies) has been performed in Germany in clinical studies since 1985 in patients suffering from colorectal cancer. After having been successfully proven in primary studies, RIS is now being used in the early diagnosis of recurrences and metastases. In the prospective study presented here the clinical usefulness of RIS was assessed in comparison against well-tried diagnostic methods including computed tomography in patients suffering from colorectal cancer. It was shown that RIS in SPECT technique (= single photon emission computed tomography) with 99mTc-labelled monoclonal CEA antibodies can visualise local recurrences if diagnostic findings are doubtful, with a sensitivity of 78% versus 50% for CT findings.

[The HR computed tomography of interstitial lung diseases]

In 50 patients with pulmonary disease of varying aetiology and involvement of the pulmonary interstitium, high resolution CT with 1 mm sections have been performed. Various morphological changes within the secondary lobule could be demonstrated which helped in reducing the differential diagnosis. Compared with conventional CT with 10 mm cuts it was also possible to improve the demonstration of pleural lesions by changing window levels.

[Lymphocytic infiltrations of the orbit in MRT and CT. Lymphoma, pseudolymphoma and inflammatory pseudotumor]

MR and CT examinations of 16 patients with lymphoma, pseudolymphoma and inflammatory pseudotumours were analysed to describe morphologic features of lymphocytic infiltration. Density and signal did not allow for differentiation, but localisation was the most important criterion: lymphoma and pseudolymphoma were located in the anterior superior orbit, inflammatory pseudotumours being retrobulbar lesions. Differentiation is of clinical importance, since both lymphoma and pseudolymphoma are accompanied by generalised malignant lymphoma while inflammatory pseudotumours are localised. Imaging of topographic relations of lens, optic nerve and lesion on sagittal MR images was found helpful for radiation therapy planning.

[Cervical lymph node metastasis: significance of computerized tomography and palpation. A histologically controlled comparison]

Palpation and CT are used before treatment, in addition to sonography, in patients with tumours in the head and neck for lymph node staging. The accuracy of CT in identifying lymph node metastases is 79% and in our clinical material is similar to the accuracy of palpation (81%). Sensitivity of CT (93%) is better than palpation (82%). Specificity of CT (65%) is less than that of palpation (82%). The high percentage of false positives from CT (35%) is due to enlargement of the lymph nodes resulting from sinus histiocytosis or follicular hyperplasia. CT is significantly superior to palpation in demonstrating the relationship of the lymph nodes to the surrounding tissues (vessels, muscles, bones).