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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.

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%).

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%).

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.

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.

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.

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.

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).

In 32 patients with fractures of different localisation the transverse CT layers were compared with three-dimensional reconstructions. Evaluation showed that three-dimensional CT can better visualize complicated anatomical conditions especially if there are dislocated fragments in the facial part of the skull and in the trunk of the body. Hence, 3-D CT is a valuable complement to axial CT which, however, remains the basis of the findings. Misinterpretations are possible of the reconstructions are used alone because of the lack if visualization of the lesions of the soft parts that accompany fractures and because there may be pseudoforamina at thin osseous lamellae.

184 liver metastases in 30 patients were examined retrospectively and the imaging in sonography, dynamic CT and plain CT was compared. Dynamic CT is markedly superior to plain CT and sonography in respect of the delineation of liver metastases, especially also in the identification and location of diffuse metastases.

This is a prospective study of the value of dynamic CT with a rapid scan frequency for the control of liver transplants. In 28 patients dynamic CT was performed with table movement and angio-CT without table movement, using a standard contrast bolus. In 97% of cases the central portions of the portal and hepatic veins could be delineated. The peripheral vessels were better demonstrated by angio-CT (79%) than by dynamic studies with table movement (47%). Parenchymal lesions, such as infarcts, and changes round the liver, such as lymphoedema or haematomas, were adequately demonstrated by either method. In addition, angio-CT provided information on abnormalities of perfusion within the transplant.

Fifty patients with various diseases of the petrous bone were examined by HR-CT with a 1024 x 1024 matrix. It is demonstrated that the improved spacial resolution results in a better discrimination of subtle anatomical structures and therefore leads to an expansion of the diagnostic possibilities in diseases of the auditory and vestibular organs. Evaluation of the two-dimensional reconstructed images shows that best quality is obtained with contiguous 1 mm, sections in the primary scans. In most cases these reconstructed images are diagnostically sufficient. In addition they help to reduce patient strain (no problem with patient positioning, no further x-ray exposure, time-saving). Three-dimensional reconstructions from the base of the skull allow a good visualization of complex and extensive osseous destructions of the temporal bone. The disadvantage of this method is on the one hand the lacking representation of soft tissue and the poor spacial resolution (no 3-D imaging of the ossicular chain), and on the other hand the smoothing of contours because of arithmetical filters. Thus tumor expansion and finer osseous erosions may not be distinguishable. Consequently, 2D primary or reconstructed images must continue to be the basis of diagnosis.

In 25 patients in whom oral surgery was required, we examined what additional information can be obtained via three-dimensional CT compared with conventional transverse CT scans. We showed that D-3 CT facilitated the spatial orientation by complex osseous destructions. Better therapy planning and postoperative control was therefore feasible. However, CT diagnosis continued to be based on transverse scans.

In this prospective study 39 patients with malignant liver tumours were examined by rapid CT. CT was performed before contrast, as dynamic CT, with and without table movement and, in some patients, images were obtained four hours after contrast injection. Time/density curves of hepato-cellular carcinomas (nine cases) showed more rapid and more intense enhancement of the tumour than of the liver parenchyma, whereas tumours of biliary origin (ten cases) showed a slower and less marked enhancement than surrounding tissue. In addition, it was possible to differentiate hypovascular metastases (18 cases) and hypervascular lesions by means of the time-density curve. Best diagnostic information was obtained by dynamic bolus CT. This method without table movement is best for differentiating focal lesions, whereas dynamic CT with table movement shows the extent and number of tumour lesions.

13 bypasses and 8 patches were examined by ultrasound in vitro with a 3.5 MHz and a 10 MHz probe. Whereas only 6 bypasses were assessable by sonography, all patches could be demonstrated in vitro. In these cases, sonography could be accomplished with either of the two frequencies used. The 10 MHz probe was superior for imaging structural details. Immediate postoperative sonography of such grafts, which cannot be demonstrated accurately in vitro, is not reliable.

A comparative study of MRI, CT and ultrasound of orbital tumors revealed that only for malignant melanomas and orbital pseudotumors MRI had the most diagnostic relevance. Malignant melanomas could be differentiated from a haematoma due to their characteristic T1 and T2 signal intensity. MRI is impaired by its long examination time and the danger of quality reduction caused by motion artifacts.

Intravenous and intra-arterial digital subtraction angiography is able to demonstrate hypervascular tumours in the ear, nose and throat territory. Direct puncture of a venous bypass used for intra-arterial chemotherapy, within the external carotid artery territory, is devoid of risk and can be used for assessing the accessibility of the tumour. Lesions of low vascularity can only be recognised by DSA on the basis of vessel displacement. These lesions are not a primary indication for examination by digital angiography.

In a retrospective study, the clinical usefulness of digital image intensifier radiography was analysed. It could be demonstrated that for angiographic procedures the image quality of a 1024(2) matrix is superior to a 512(2) matrix. For digital excretory urography it could be seen that in 80 to 90% the images were at least sufficient to analyse the renal pelvis. Digital image intensifier radiography of bones was diagnostically sufficient in 76% and analysis of bone architecture was possible in 85%.

In 60 patients with an average age of 60 years, the essential angiographic findings of renal cell carcinoma were analysed and described in order of their frequency. Localisation, size and vascularisation were evaluated. Involvement of the v. cava inferior and/or of the v. renalis was found with 13% of the tumours on the right and with no tumour on the left side. It is recommended not to perform cavography in case of correct filling of the left renal vein in the late phase of angiography.

The quality of radiographs representing corkscrew vessels and collateral vessels that developed after occlusion of the superior femoral artery, using digital angiography technique with a 1024 matrix, is compared with that of a 512 matrix. The images obtained with the 1024 matrix were superior to those obtained with a 512 matrix. Using a small cannula for the application of the contrast agent, the quality of the images representing the collateral vessels was very good in 83% of the images produced with the 1024 matrix and in 70% of the 512 matrix images.

The diagnostic possibilities of intraarterial DSA are demonstrated by means of 76 investigated haemodialysis shunts. No complications were seen. In 85% of the cases venous stenoses or occlusions were proved. 18% of these were localised in the proximal part of the draining veins. For this reason, investigation of the venous inflow into the V. cava superior is recommended in every case.

The ultrasonographic findings of 43 patients with AIDS and ARC were analyzed. In 63% an enlarged liver, in 66% an enlarged spleen, partially with focal lesions, and in 21% enlarged abdominal lymph nodes were diagnosed. The typical parenchymal lesions of the kidney (focal segmental glomerulosclerosis) were not observed. Abdominal ultrasound is the first diagnostic procedure to perform in patients with AIDS and ARC with the suspicion of abdominal pathology. With additional thin needle puncture of the lesions a histological verification of the pathologic findings is possible.

MRI of the orbit with surface coils was performed in 40 patients. In 35 cases the findings were pathologic. The most frequent (n = 9) were malignant melanomas of the choroid, which were distinguishable from hemorrhages (n = 2) by the characteristic signal intensity pattern. MRI only offered advantages over CT in lesions of the orbital apex, the upper part of the orbit, and in the diagnosis of inflammatory processes. In most of the cases of orbital tumors, and particularly where there was involvement of bony structures, CT was equal to or better than MRI.

In a prospective study, 150 threedimensional reconstructions of patients with bone diseases were analyzed. It could be seen that 3 D images were relevant for therapeutic considerations in diseases of craniofacial bones, and to a lesser degree for other skeletal regions. In no case was the 3 D reconstruction the only important factor for the therapeutic decision. The study demonstrated that 3 D imaging of the pelvic bones, especially for necroses of the femoral head, is severely limited without the possibility of computer-aided disarticulation.

The ultrasound findings of 58 patients with AIDS and ARC were analysed retrospectively. In 55% an enlarged liver, in 62% an enlarged spleen, partially with focal lesions, and in 21% enlarged abdominal lymph nodes were diagnosed. The typical focal segmental glomerulosclerosis of the kidney was observed in one case, and cholangitis in 2 patients. Abdominal ultrasound is the first diagnostic procedure to be performed in patients with AIDS and ARC when abdominal pathology is suspected. With US-guided thin needle puncture of the lesions, a histological verification of the pathologic findings is possible.

Report on a woman patient with an idiopathic hepatic duct cyst, who had been followed up by us over a period of 12 years and who was a laparotomy case for 4 times. On the basis of intraoperative results and the course of the disease we were able to collect information on the growth and involution of the cyst, as well as on the influence exercised on the clinical picture. If resection of a cyst with drainage of the gall passages to the jejunum by means of Roux sling proves too dangerous, it would be better to choose a simple drainage operation; in this regard we prefer a transduodenal interior connection to an exterior one.

Today the best radiotherapeutic procedure for treating small choroidal melanomas involves the application of rhutenium 106, thereby sparing the bulbus, or application of iodine 125 in larger tumors. In extensive tumors, the additional use of local hyperthermia promises further enhancement of brachytherapy with applicators. In the foreseeable future, therapeutic concepts primarily for the palliative treatment of advanced, metastasing melanomas might include the use of antimetabolites or therapy with monoclonal radioactively changed antibodies.

The use of digital image radiography in urographic diagnostics yields a high percentage of images that are useful in diagnosis, even at the present state of technical development which is rapidly improving. Our own results obtained in a prospective study on 75 patients supply proof of such diagnostically useful pointers. Clear improvements in demonstrating the details when employing a 28 cm image amplifier input format in place of the additionally used 40 cm are seen only with the system of the renal calices. However, we found that the 40 cm image amplifier input format proved satisfactory in respect of assessing renal contours, kidney pelvis and ureters as far as image quality was concerned. Enhance image quality can be expected in future from the use of wedge-shaped diaphragms as well as a selective influencing of the automatic exposure (several measurement chambers, weighting factors) and the transfer of monitor screen contents to hard copy without incurring any losses during transfer.

Intravenous DSA was performed on 45 patients for diagnosis of otorhinolaryngologic diseases. Hypervascular glomus tumours can be accurately diagnosed. Furthermore, vascular architecture and topography can be analysed to allow the planning of tumour embolization or surgery. Hypovascular tumours are inadequately demonstrated by intravenous DSA. A specific and detailed analysis of thin vessel architecture in malignant tumours is impossible by intravenous DSA.

100 intravenous digital subtraction angiograms of bifurcations were compared to one hundred plain film arteriograms. Both types of examinations were of excellent image quality. Arteriosclerotic lesions in the posterior circumference of the internal carotid artery were found in 55% plain film angiograms and in 49% of intravenous DSA examinations. Plain film angiography was significantly more accurate in the evaluation of arteriosclerotic ulcerations than i.v. DSA. The total amounts of arteriosclerotic stenoses with a smooth or rough surface were equal with both methods. The interindividual comparative study demonstrated that in respect of diagnosis of ulcerative lesions, i.v.. DSA is inferior to plain film angiography, even if an excellent image quality for all projections is achieved in i.v. DSA.

Radioimmunoscintigraphy (RIS) with 131I labeled OC-125 F(ab')2 monoclonal antibody fragments was prospectively studied in 43 women for primary diagnosis and follow up of ovarian cancer. Total body planar photoscans with a scintillation camera were performed one to seven days after antibody application and results were compared with operation and or CT examination. By the region of interest technique the tumor to non tumor tissue ratio (T/N) was calculated in vivo. Sensitivity in primary diagnosis was 100% (10/10), specificity 33% (1/3). For local recurrency, sensitivity was 86% (19/22), for metastatic loci 80% (17/21). Specificity was 75% and 50%. T/N ratio was in the rage from 1.3 to 2.8. Sensitivity for ovarian cancer is high in primary diagnosis and follow up. By the region of interest technique it is possible to detect small recurrencies and to presume peritoneal carcinosis. Antibody accumulations in diseases different from ovarian cancer however diminish specificity.

34 patients with skeletal alterations mostly in the periphery were investigated by digital image intensifier radiography (DIIR). A high resolution image-intensifier system (1024 x 1024 matrix, 40 cm, 28 cm, 14 cm image intensifier, maximal spatial resolution: 3.6 lp/mm) was available. The image quality was diagnostic sufficient in 76% using DIIR. A good or very good image quality of fine-structures was obtained only in 41%. The quality deficits in comparison to conventional radiograms were particularly obvious in investigation of the phalangeals. Logarithmic amplification and software upgrading lead after these first clinical investigations to a better image quality.

33 CT-studies of 26 patients with alloplastic vascular prostheses were evaluated and compared with postoperative digital subtraction-angiography in 16 cases. 13 patients had no pathologic findings confirmed by further clinical development. In 4 cases bypass infection was diagnosed, which CT findings were perigraft gas (2/4), perigraft fluid (4/4), cm-enhancement (4/4) and fistulas (2/4). 10-21 d. post.-op. sterile hematomas were found in 3 patients. Further 3 cases had 5 weeks-2 post.-op. perigraft seromas. CT was method of first choice for diagnostic of perivascular alterations after bypass surgery. DSA was complementary to CT and should be performed to detect vascular complications.

Sonography enables sensitive detection of pathological changes in the scrotum, since the planes of intersection can be selected as may be required, and since local resolution is excellent. However, sonographic criteria alone do not permit differential diagnosis of malignomas against benign changes. Anamnesis and clinical examination are of equal importance as sonography. Diagnostic conclusions are possible only if all the findings based on all the diagnostic approaches are combined in synopsis. Although reports published in recent years postulated transducer either of a frequency higher than 3.5 mHz (1, 5, 11, 12, 13, 14, 17, 20, 21, 24, 25, 27) or low-frequency transducers associated with immersion technique (7, 23), in our patients the use of a 3.5 mHz convex scanner with water forerun resulted always in confirming the diagnosis (in conjunction with anamnesis and clinical findings). In our experience a transducer of this frequency (3.5 mHz) with water forerun appears to be suitable for routine diagnosis of changes in the scrotum. This is an important aspect in general practice, where ultrasound equipment is often fitted with 3.5 mHz transducers.

740 patients with findings of cerebrovascular insufficiency were investigated by duplex sonography and frequency-analysing cw doppler. In 620 pathological arteries not stenosing lesions of the carotid bifurcation were found most frequently (93%). In 35% moderate-severe stenoses of the a. carotis interna were diagnosed. The advantage of duplex sonography and cw doppler in combination is the addition of both methods, so that a very reliable diagnosis of the extracranial carotis is possible.