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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.

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.

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.

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.

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.

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.

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 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.

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.

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.

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.

A total of 44 patients were evaluated to compare the value of B-mode sonography, Doppler sonography and colour coded Doppler sonography. All patients were studied because of suspected lesions of the femoral arteries following diagnostic and/or therapeutic cardiac catheterisation. B-mode sonography was unable to reliably differentiate between haematoma and pseudo-aneurysms, a.v.-fistula or combined lesions. Colour coded Doppler sonography can better demonstrate haematoma and thrombi in pseudo-aneurysms. The neck of a pseudoaneurysm can be exactly depicted by colour coded Doppler sonography. A.v.-fistula is shown by colour coded Doppler sonography based on typical colour coding and the Doppler spectrum. Combined lesions of pseudo-aneurysm and a.v.-fistula cannot reliably be detected by colour coded Doppler sonography, duplex sonography and B-mode sonography.

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.

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.