Search

Purpose: To assess the MR arthrographic findings of bicipital tenosynovitis in correlation with arthroscopy.Design and Patients: The shoulder MR arthrographies of 500 consecutive patients were retrospectively analyzed for signs of bicipital tenosynovitis and associated pathologies. Forty patients (8%) had MR evidence of bicipital tenosynovitis, but only 17 (3%) with arthroscopic confirmation were included in the study. The MR findings in these patients were compared with those of 10 patients with rotator cuff lesions but arthroscopically normal long biceps tendons. MR arthrography was performed with 10-15 ml of a 250 mmol/l gadoterate meglumine (Gd-DOTA) solution injected under fluoroscopic guidance, and transaxial, oblique coronal and sagittal MR sequences were obtained.Results: All 17 patients showed one or more abnormal findings: signal increase in the tendon with or without fusiform distension was seen in 12, surface irregularities in six, adhesions in 11 and noncommunicating effusions of the tendon sheath in six. Associated abnormalities of the rotator cuff were present in 16 while the seventeenth patient had glenohumeral synovitis without rotator cuff pathology. MR arthrograms correlated with arthroscopic findings in the joint but comparison was not possible in the intertubercular groove portion of the biceps tendon. None of the 10 patients with an arthroscopically normal biceps tendon showed any of the MR findings of bicipital tenosynovitis.Conclusion: Bicipital tenosynovitis is detectable by MR arthrography. In most cases it is an associated finding of rotator cuff abnormalities and likely to have a similar etiology. When lesions of the anterior rotator cuff are recognized, the biceps tendon should be scrutinized for inflammatory changes. [ABSTRACT FROM AUTHOR]

Background and Objectives: We prospectively compared five techniques to estimate predicted postoperative function (ppo F) after lung resection: recently proposed quantitative CT scans (CT), perfusion scans (Q), and three anatomical formulae based on the number of segments (S), functional segments (FS), and subsegments (SS) to be removed., Methods: Four parameters were assessed: FEV(1), FVC, DL(CO) and VO(2max), measured preoperatively and 6 months postoperatively in 44 patients undergoing pulmonary resection, comparing their ppo value to the postoperatively measured value., Results: The correlations (r) obtained with the five methods were for CT: FEV(1) = 0.91, FVC = 0.86, DL(CO) = 0.84, VO(2max) = 0.77; for Q: 0.92, 0.90, 0.85, 0.85; for S: 0.88, 0.86, 0.84, 0.75; for FS: 0.88, 0.85, 0.85, 0.75, and for SS: 0.88, 0.86, 0.85, 0.75, respectively. The mean difference between ppo values and postoperatively measured values was smallest for Q estimates and largest for anatomical estimates using S. Stratification of the extent of resection into lobectomy (n = 30) + wedge resections (n = 4) versus pneumonectomy (n = 10) resulted in persistently high correlations for Q and CT estimates, whereas all anatomical correlations were lower after pneumonectomy., Conclusions: We conclude that both Q- and CT-based predictions of postoperative cardiopulmonary function are useful irrespective of the extent of resection, but Q-based results were the most accurate. Anatomically based calculations of ppo F using FS or SS should be reserved for resections not exceeding one lobe., (Copyright 2002 S. Karger AG, Basel)

Transmetalations of zincates succeed only after activation of the barium metal. Dialkylbarium, the initial product, metalates the zincate anions which are still present in solution and leads to the formation of tetraanionic tris(zincate) ligands, which sterically shield the Ba-C bonds of a Ba 4 Zn 2 C 6 cage., (© 2001 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.)

Purpose: The purpose of this work was to investigate thin section CT image enhancement of subtle areas of decreased attenuation of the lung parenchyma in suspected airways disease., Method: Forty-seven consecutive patients with chronic sputum production underwent pulmonary function tests and high resolution CT (HRCT). Single section inspiratory (INSP), expiratory (EXP), and minimum intensity projection (MINIP) images through the lower lobes were acquired. A histogram stretch was applied to the INSP and MINIP images, generating two further image formats. The five image types were compared for the extent of decreased attenuation, observer confidence, and correlations with pulmonary function tests., Results: Interobserver variation was lowest with MINIP images (mean weighted K: MINIP 0.70, INSP sections 0.65, other image formats < or =0.48). Observers were most confident with EXP and MINIP images. EXP sections identified more disease than MINIP images (p<0.001). Correlations with pulmonary function tests were similar for each image format., Conclusion: The HRCT changes of small airways disease are enhanced with image postprocessing. MINIP images are associated with increased observer confidence and agreement as compared with HRCT alone.

The purpose of this study was to investigate whether hypoxic pulmonary vasoconstriction is the major determinant of the computed tomography (CT) pattern of mosaic attenuation in asthmatic patients with induced bronchoconstriction. Thin-section CT was performed at suspended full inspiration immediately and 30 min after methacholine bronchoprovocation in 22 asthmatic subjects, who were randomly assigned to breathe room air (group A, n = 8), oxygen via nasal prongs at 5 l/min (group B, n = 8), and oxygen via face mask at 12 l/min (group C, n = 6). CT changes were quantified in terms of global lung density and density in hypodense and hyperdense areas. Lung parenchymal density increases were greatest in group C and greater in group B than in group A, globally (P = 0.03) and in hypodense regions (P = 0.01). On bivariate analysis, the only change in cross-sectional area was related to change in global density. In hypodense regions, density change was related both to reduction in cross-sectional area (P < 0.0005) and to oxygen administration (P = 0.01). After correction for changes in global lung density, only oxygen was independently related to density increase in hypodense areas (P = 0.02). In induced bronchoconstriction, the CT appearance of mosaic attenuation can be largely ascribed to hypoxic vasoconstriction rather than to changes in lung inflation.

Pathology of the rotator cuff is the cause of most common problems at the shoulder joint. Acute injuries are not as frequent as chronic cuff disease, but often they aggravate inflammatory or degenerative tendon alterations, even if they are of minor severity. Traumatic rotator cuff tears predominantly affect the supraspinatus tendon or the rotator interval. The subscapularis tendon is involved in anterior dislocations of the glenohumeral joint or in direct trauma. Plain film radiography still remains the base of all further imaging studies. If only full-thickness tears must be ruled out, double-contrast arthrography and ultrasound are acceptable imaging modalities. However, the former has a drawback in being invasive and does not detect partial tears at the bursal site of the cuff or rotator cuff tendinopathy, whereas the latter heavily depends on the experience of the radiologist and is restricted to the rotator cuff. Nowadays the most comprehensive imaging method is magnetic resonance (MR) imaging. MR imaging enables the detection or exclusion of complete rotator cuff tears with a reasonable accuracy and is also suitable to diagnose further pathologies of the shoulder joint. MR arthrography is valuable in the detection of subtle anatomic details and further improves the differentiation of rotator cuff diseases. Although in comparison MR imaging is still the most expensive imaging method, its high negative predictive value for the diagnosis of complete rotator cuff tears and its reliability evaluating different shoulder joint pathologies make it the preferred imaging modality.

Lesions of the long head of the bicepstendon (BT) are seen in association with tears of the rotator-cuff, particularly lesions of the subscapularis tendon and the rotator-interval. The frequency of positive MR-findings at the BT is approximately 25%. The pathologic alterations include complete medial luxation, subluxation and entrapment by the subscapularis tendon, tendinitis or tendovaginitis and lesions at the origin of the tendon at the superior labrum (superior labrum anterior to posterior (SLAP)--lesions). The imaging signs of BT pathology on MR include an abnormal course and position of the tendon, alterations in shape and changes in signal-intensity (SI), obliteration and thickening of the tendon-sheath. In long standing intra-articular BT rupture, neo-insertion of the tendon in the bicipital sulcus may ensue. The long BT needs to be visualized in transaxial, coronal oblique and sagittal oblique projections. Besides serving as stabilizer of the long head of biceps muscle, the BT is also an important stabilizer of the anterior joint capsule.

Objective: MR arthrograms were retrospectively reviewed for susceptibility artifacts induced by accidental injection of a small amount of gas when paramagnetic contrast solution was injected. A pitfall to interpretation, an unusual distribution of intraarticular gas into the sheath of the long biceps tendon that resembled a rope ladder, was observed and compared with findings of bicipital tenosynovitis., Conclusion: Intraarticular gas contamination during MR arthrography must be differentiated from intraarticular loose bodies and findings of bicipital tenosynovitis. Most reliable for the differential diagnosis are the different shapes and sizes of the gas-induced susceptibility artifacts on spin-echo and gradient-recalled echo images.

After an introduction, three selected contributions to the 10th Course on Radiation Protection held at the University Hospital of Basel are presented. The principles of radiation protection and new Swiss legislation are discussed as the basis for radiological protection. Ways are proposed of reducing radiation exposure while optimizing the X-ray picture with a minimum dose to patient and personnel. Radiation effects from low doses. From the beginning, life on this planet has been exposed to ionizing radiation from natural sources. For about one century additional irradiation has reached us from man-made sources as well. In Switzerland the overall annual radiation exposure from ambient and man-made sources amounts to about 4 mSv. The terrestrial and cosmic radiation and natural radionuclids in the body cause about 1.17 mSv (29%). As much as 1.6 mSv (40%) results from exposure to radon and its progenies, primarily inside homes. Medical applications contribute approximately 1 mSv (26%) to the annual radiation exposure and releases from atomic weapons, nuclear facilities and miscellaneous industrial operations yield less than 0.12 mSv (< 5%) to the annual dose. Observations of detrimental radiation effects from intermediate to high doses are challenged by observations of biopositive adaptive responses and hormesis following low dose exposure. The important question, whether cellular adaptive response or hormesis could cause beneficial effects to the human organism that would outweigh the detrimental effects attributed to low radiation doses, remains to be resolved. Whether radiation exerts a detrimental, inhibitory, modifying or even beneficial effect is likely to result from identical molecular lesions but to depend upon their quantity, localization and time scale of initiation, as well as the specific responsiveness of the cellular systems involved. For matters of radiation protection the bionegative radiation effects are classified as deterministic effects or stochastic effects respectively. The various histopathological reactions of tissues and organs following localized tissue irradiation, and the radiation syndromes following total body irradiation, constitute the deterministic effects. There will be a threshold below which deterministic effects do not appear and spontaneous incidences are not known. For low dose risk considerations deterministic effects are of no significance. Genetic effects and carcinogenesis are said to be stochastic effects. Characteristically the probability of stochastic effects increases with dose but the severity of the effects is independent of the dose. The shape of the dose-response relationship at intermediate to high dose levels is linear-quadratic. For exposure to low doses the response becomes linear, as is to be expected for a linear-quadratic function at low dose. No threshold is assumed for stochastic effects. The estimate of probability of fatal cancer by the ICRP is 4 x 10(-2) per Sv for the working population and 5 x 10(-2) per Sv for the total population. Their estimate of probability of serious hereditary disorders within the first two generations is 1 x 10(-2) per Sv. The highest probability coefficient is attributed to mental retardation following exposure in utero. Within the sensitive period at 8-15 weeks of gestation, a risk probability of 40 x 10(-2) per Sv is assumed but a threshold at 0.1 Sv is not excluded. Conclusions drawn from experiments, clinical observations and epidemiological studies following intermediate to high radiation exposures attribute a mutagenic and carcinogenic competence to all radiation doses. Microdosimetric considerations support this assumption. This conclusion cannot be confirmed experimentally nor by epidemiological studies of populations living under different conditions from natural sources of radiation. Nevertheless, a change in the present restrictive radiation protection policy does not yet appear appropriate.

The purpose of this study was to evaluate the time dependency of the contrast-to-noise ratio (CNR) of head and neck malignancies during contrast-enhanced MR imaging. Then we would compare the CNR of dynamic snapshot gradient-echo (SGE) images with conventional spin-echo (SE) and fast spin-echo (FSE) sequences. Fifteen patients with squamous cell carcinomas were examined with T1W-SE, T2W-FSE, contrast-enhanced Gd-T1W-SE, and T1W-SGE sequences, the latter statically and contrast-enhanced dynamically. The CNR for all sequences and adjacent tissues was computed and the time to reach maximal CNR (Tmax) was determined for dynamic studies. The CNR was time dependent with two distinct Tmax at 6-18 and 60-160 s which corresponded to two different tumor enhancement patterns. Neither enhancement pattern correlated with distinct histologic findings or tumor grading. The CNR improved for the Gd-T1W-SE images. The improvement was statistically significant in relation to T1W-SE and Gd-T1W-SE images at the floor of the mouth and at the tongue base. The good CNR of the dynamic Gd-T1W-SGE measurements justifies further investigations of this method in order to improve tumor delineation.

Objective: A clinical and histopathological comparison of 2D spin-echo (SE) and 3D gradient-echo (3DGE) sequences was undertaken for the knee joint. The purpose of the study was to evaluate the clinical results and to explain the different appearances of meniscal abnormalities on both 2DSE and 3DGE images., Patients, Materials and Methods: The clinical study comprised 45 patients with arthroscopically correlated MR imaging results. For the histopathological correlation, seven cadaveric knee joints were examined with the same 2DSE and 3DGE (FISP) imaging protocol and sliced in sagittal sections according to the MR images. Different stainings were used., Results: For the detection of meniscal tears, accuracy (82.2%) and positive predictive value (70.7%) of the 3DGE sequence were limited due to a high number of false positive findings. Cartilaginous lesions were more easily visible on 3DGE than on 2DSE images (sensitivity: 63.1% vs. 52.6%, respectively). As in the clinical study, the meniscal signal abnormalities of the cadaveric knee joints were much more extensive on the 3DGE images than on the 2DSE images. The 3DGE findings correlated better with degenerative meniscal changes which were visible microscopically., Conclusion: The high sensitivity of the 3DGE sequence for degenerative meniscal changes explains the lack of specificity for the differentiation between meniscal degeneration and tears with this sequence. The MR grading system for meniscal lesions is of limited value for the evaluation of 3D FISP images.

Purpose: This paper compares a new film-screen system (FSS) called INSIGHT Skeletal Imaging System with the previously used Lanex/T-MAT G FSS., Material and Methods: Using a Bronder phantom, measurements were made of dose, resolution and contrast. 135 skeletal phantom images were assessed in order of quality by six observers., Results: Comparable high resolution film-screen combinations (FSC) showed similar geometric resolution. Comparing high intensifying screens, the new INSIGHT Skeletal Regular FSS showed better resolution than the Lanex medium FSC. Dose reduction for the INSIGHT Skeletal Imaging FSS was 29-56%. The new FSS showed image quality similar to high resolution screens but was significantly better when using high intensifying screens., Conclusion: The new INSIGHT Skeletal Imaging System can replace the Lanex/T-MAT G FFS by retaining quality but reducing radiation dose by 29-56%. Using the new high intensifying FSC, images showed in addition improved film quality.

We observed a serious arterial hemorrhage as a complication of percutaneous transhepatic biliary drainage (PTBD). The hemorrhage appeared during catheter placement for implantation of an endobiliary stent as a two-step procedure. It was caused by an arterial pseudoaneurysm and could be successfully treated by superselective embolization. Although there was a preexisting cavernous transformation of the portal vein no signs of liver cell necrosis appeared after embolotherapy. Vascular complications of PTBD will be discussed with regard to their frequency, possible etiology, ways to avoid them and their interventional therapy.

Imaging methods, especially CT and for specific questions MRI, are an essential part of diagnosis and staging of non-small cell lung cancer. They are effective methods for the detection of unresectable tumours and avoid the necessity for further invasive examinations and explorative thoracotomies. The judgement of lymph node size by CT suffers from a limited accuracy. Nevertheless, it allows guided bronchoscopical staging biopsies of enlarged mediastinal lymph nodes (> 1 cm) and, therefore, a selective indication of mediastinoscopy. CT scans of the thorax usually are extended to the adrenal glands and the liver to exclude metastasis. Extrathoracic scanning beyond the upper abdomen and bone scintigraphy should be restricted to patients with clinical indicators or symptoms. The combined application of imaging methods, bronchoscopy, and mediastinoscopy provides better selection of surgical candidates and hence reduces the rate of unresectable operations.

MRT offers some advantages for morphological examinations of the fossa poplitea and appears to be superior in terms of multiplanar imaging over CT and duplex sonography for identifying a PAES. The method is always indicated when the diagnosis of PAES is suspected from the primary duplex sonography but the verification of the anatomic alteration is not conclusive. An MR angiography can, in principle, be carried out in the same session. On consideration of the currently presented cases, both inflow and phase-contrast MRA appear to be suited for examination. However, a sufficient detail resolution is only achieved by use of a surface coil which then makes assessment of the contralateral side and the lower leg arteries impossible. Specially fitted coils which allow a double-sided representation of sufficient image quality may, however, make conventional angiography unnecessary in future.

Chest radiographs and CT images of 25 patients with pleural empyemas were compared retrospectively with those of 20 patients with pleural exudates and transudates in order to determine criteria for differential diagnosis and to define the place of CT in the diagnosis of pleural empyemas. The sign which was most suggestive of an empyema on a chest radiograph was an encapsulated effusion in an atypical position (18/25); this was found in only 4 out of 20 exudates and in none of the transudates. On CT, changes in the pleura, the subcostal tissues and the configuration and position of the fluid were suggestive of an empyema. In nearly all patients with a pleural empyema there was thickening and increased contrast uptake of the parietal pleura (22/25) and thickening and increased density oft the subcostal tissues (23/25). Usually, empyemas were encapsulated and biconvex (20/25). None of the patients with pleural transudates showed any of these changes. In the presence of some pleural exudates, pleural (14/20) or thoracic (11/20) changes were noted. In part, these changes were due to previous treatment (sclerotherapy) or tumour infiltration (7/20). An attempt to correlate the CT findings with changes in the pleura and subcostal tissues with the clinical empyema stages I-III, according to Light, showed that CT was unable to distinguish between early and late empyemas. Consequently, diagnostic aspiration remains necessary for correct treatment.

The MR images of the knee joint of 100 successively examined patients were evaluated in retrospect with regard to periarticular cystic lesions. There were 18 popliteal cysts, 8 meniscal cysts and 4 ganglion cysts. Localisation and internal structure of the lesions were of main importance in respect of differential diagnosis. All meniscal cysts were associated with horizontal meniscal tears. Spin-echo and 3D gradient-echo images did not enable differentiation because of signal intensity values. A spin-echo sequence with long repetition time in double-echo technique was best suited to assess the periarticular cystic lesions as well as the intraarticular pathological changes which were often concomitant.

In 20 patients with multiple myeloma, the results of MR, x-ray, bone scintigraphy, bone marrow scintigraphy and bone marrow biopsy were compared. MR proved the most sensitive imaging method for the detection of bone marrow infiltration followed by x-ray examinations. Bone marrow scintigraphy and especially bone scintigraphy revealed false-negative results more often. These findings were more impressive by the direct comparison of several investigated regions showing different findings of each imaging method. False-positive results were not found. In 4 patients false-negative results of bone marrow biopsy had to be assumed because of definitely pathological findings by x-ray and MRI.

Thirty-one pediatric patients with brain tumors--25 primarily diagnosed, 6 recurrences--underwent MR and CT examinations before and after application of contrast media. Tumor detection, delineation of the tumor extent and definition of the tumor type were compared. Gd-DTPA-enhanced MR was superior in delineating the extent of primarily diagnosed tumors, which showed enhancement (n = 22). The tumor detection (1/6) and the identification of the tumor margins (5/6) were improved by Gd-DTPA in the 6 recurrences. Tumors without enhancement (n = 3) were judged by T2-weighted images better than by CT. The results suggest that Gd-DTPA is indicated for the evaluation of brain tumors in pediatric patients as well, especially since it offers advantages distinguishing between tumor types. Only the detection of tumor calcifications, which is rarely specific, is not possible by MR.

Apart from the difficult differential diagnosis of hydatid liver disease, diagnostic problems may increase in chronic disease because of complications. Compression or infiltration of bile ducts is the most common complication occurring in 16%. Other complications are infiltration of adjacent organs and structures, for instance the right kidney and the diaphragm, or the (often iatrogenic) rupture of hydatid cysts with intraperitoneal spread. Preoperative sonographic diagnosis is important in influencing the surgical procedure.

After perforating eye injury the retention of a foreign body in the orbits has to be excluded. Wooden foreign bodies mostly have negative density on CT, which increases later as a result of granulomatous changes. On MRI, pieces of wood appear with low signal intensity, and only in some cases is a collar-shaped structure recognizable, allowing differentiation from gas. Soon after orbital trauma with splinters of wood, therefore CT allows better differentiation of pieces of wood from intraorbital gas by measurement of their density, whereas MRI, makes it possible to demonstrate wooden foreign bodies in older injuries in spite of granulomatous changes.

A prospective study compared duplex sonography and magnetic resonance imaging in evaluating renal transplants. One hundred and two duplex sonographic and 24 MR examinations were performed and correlated with clinical course or biopsy. All normal renal allografts, 6 transplants with acute tubular necrosis and 2 cases of cyclosporin toxicity had normal Doppler waveforms, whereas 9 renal transplants with evidence of interstitial rejection by biopsy showed an obliteration or reversal of diastolic flow. MR imaging was less specific in identifying allograft rejection. There were false positive results in normal renal transplants, allografts with acute tubular necrosis and after rejection therapy. With regard to cost, accessibility and specificity, duplex sonography is the method of choice for the evaluation of renal allografts.

Ultrasonography is the method of choice for the detection of medullary or cortical nephrocalcinosis in infancy and childhood. Compared with abdominal radiographs and computed tomography even smallest calcifications are detected more accurately. Using furosemide, ACTH, steroids or high doses of vitamin D, early forms of medullary nephrocalcinosis associated with a faint hyperechogenic rim at the margins of the renal pyramids can be diagnosed by ultrasound. Idiopathic hypercalciuria, Bartter's syndrome and renal tubular acidosis cause medullary nephrocalcinosis, whereas cortical nephrocalcinosis is the result of renal vein thrombosis; primary hyperoxaluria is associated with cortico-medullary calcifications. Due to the localisation of the nephrocalcinosis and the age distribution of the diseases, sonography merely enables us to narrow down differential diagnosis.

59 prospective duplex ultrasound studies have been performed on 30 patients after renal transplant to assess the feasibility of detection of acute rejection. The results were compared with clinical, biochemical and histopathologic findings. Real time ultrasound was not a reliable method in predicting acute rejection. Doppler sonography, however, characteristically showed a diminished diastolic blood flow in all cases of acute rejection. Acute tubular necrosis and cyclosporine toxicity were not provable, neither by real time ultrasound nor by doppler sonography. Duplex ultrasound combines the advantages of both methods in detecting perirenal fluid collections, hydronephrosis and acute transplant rejection.