The diagnostic value of magnetic resonance imaging for the detection of tumor recurrence in patients with carcinoma of the ovaries.

Disease status during follow-up evaluation of patients with carcinoma of the ovaries is the main criterion for the selection of appropriate management. A cohort analysis was performed to investigate if magnetic resonance imaging (MRI) could improve noninvasive assessment of disease status in patients with carcinoma of the ovaries during follow-up examination. Twenty-four women with carcinoma of the ovaries after primary surgical treatment with subsequent platinum containing chemotherapy were entered into the study. MRI was performed in addition to sonography and computed tomography (CT). Patients without evidence of disease underwent restaging laparotomy. Sensitivity of sonography, CT and MRI was 50, 63 and 75 percent, respectively. Combination of CT and MRI revealed a 75 percent sensitivity rate. Specificity for sonography, CT and MRI was 100, 94 and 94 percent, respectively, and for the combination of CT and MRI, 88 percent. Positive and negative predictive value and accuracy of these methods were 100, 80 and 83 percent for sonography; 83, 83 and 83 percent for CT; 86, 88 and 88 percent for MRI, and 75, 88 and 83 percent for the combination of CT and MRI. In one instance of false-negative sonographic and CT results, MRI detected recurrence located in postoperative scar tissue. In one instance, MRI did not add essential information to the other imaging methods. Therefore, MRI as a time- and cost-intensive procedure should be reserved for instances in which there are doubtful findings arising with other diagnostic tools, rather than as an indispensable routine procedure in the follow-up evaluation of patients with carcinoma of the ovaries.

Field strength dependence of MRI contrast enhancement: phantom measurements and application to dynamic breast imaging.

Differences in MRI-measured contrast enhancement have been used for tissue characterization, particularly for the characterization of mammary tumours. T1 weighted spoiled gradient echo sequences have usually been acquired for this purpose and relative signal intensity increase (Srel) has been determined to quantify contrast uptake. The field strength dependence of this technique is evaluated in this paper by phantom measurements. Srel is compared with the recently introduced "enhancement factor" (EF) and "contrast uptake equivalent" (CE) as a quantitative assessment parameter for contrast uptake. Enhancing tissues were simulated with water phantoms doped with increasing concentrations of Gd-DTPA. Spoiled gradients echo images (FLASH-2D) were obtained on a 0.2 T and 1.5 T MR system. Srel, EF and CE were determined and the results of the phantom measurements were applied to typical types of breast tissues. Srel showed a strong dependence on the magnetic field strength and was greater at higher field strengths. This is because Srel correlates positively with the native T1 which is longer at higher field strengths. Conversely, the EF and CE almost eliminated the distorting influences of the magnetic field strength. CE provided a good approximation of the actual contrast uptake. In practice, the dependence of Srel on the magnetic field strength might cause malignant lesions to be misclassified as benign at low field strengths. Either Srel criteria should be adjusted to magnetic field strength or EF and CE should be used instead of Srel for tissue characterization with dynamic contrast-enhanced MRI.

Superparamagnetic particles as oral contrast medium in magnetic resonance imaging of patients with treated ovarian cancer--comparison with plain MRI.

In 23 patients with treated ovarian cancer, 24 magnetic resonance (MR) examinations of the abdomen and pelvis were performed before and after administration of an oral superparamagnetic contrast medium. Depiction of bowel loops was judged sufficient in 47% with plain scans and in 85% with enhanced scans. Minor artefacts attributed to the agent were noted in 32% of examinations and were classified as disturbing in 8%. The diagnostic information obtained after contrast enhancement was estimated to be superior to that from plain MRI in 20% of patients. The use of oral contrast medium did not alter the MR diagnosis of "tumour recurrence" or "disease-free" in any patient. Our results suggest that superparamagnetic iron oxide is an effective and reliable approach to negative bowel contrast enhancement, increasing the confidence level when distinguishing intestines from solid structures.

A new transducer technology--the annular phased array: comparison with a conventional mechanically rotating sector transducer: the upper abdomen.

During a 3-month period, 285 patients underwent ultrasonographic examination of the upper abdomen. Scanning was done with a new annular phased array transducer, and a conventional rotating sector transducer. Our study indicates that the annular phased array is more effective for outlining boundaries of the liver, spleen and pancreas in the near and far field. Owing to improved lateral resolution, the new technology permits US imaging of parenchymal organs, even in cases of severe bowel gas obscuration.

Asymptomatic cholangitis with the acquired immuno-deficiency syndrome. Clinical and diagnostic features.

A case of hepatobiliary involvement in a 36-year-old man with the acquired immunodeficiency syndrome is presented.

[Chondromatous tumors in MRT: clinical picture in relation to localization and histopathology]. / Chondromatöse Tumoren in der MRT: Erscheinungsbild in Abhängigkeit von Lokalisation und Histopathologie.

19 patients with histologically verified cartilaginous tumours (chondromas, chondrosarcomas) were examined with magnetic resonance imaging (MRI) in order to assess differences regarding the MR appearance of these tumours which would provide information on the biological behaviour of these lesions. MR findings were then correlated with histopathology. With regard to the signal behaviour of cartilaginous tumours a good correlation with histopathology could be established insofar as the relatively hypocellular tumours composed of hyaline cartilage exhibited a high signal level on T2-weighted images. There were no significant differences regarding signal characteristics of cartilaginous tumours in various anatomical locations. However, lesions located in the pelvis and the long bones showed predominantly peripheral enhancement whereas tumours of the skull base and larynx exhibited diffuse enhancement patterns in the majority of cases. 10 tumours (6 benign, 4 malignant) exhibited a lobular appearance. No relevant information in respect of tumour grading could be obtained.

[Computed tomography in acute mediastinitis]. / Computertomographie bei akuter Mediastinitis.

Acute mediastinitis (AM) has become a rare disease since the introduction of antibiotics but still has an unchanged high mortality-rate if the diagnosis is not readily established, and adequate therapy is performed. Clinical signs of AM are often uncharacteristic, plain chest films do not allow a reliable diagnosis because of lack of sensitivity as well as specificity. In a retrospective study the CT-results of 23 patients clinically suspect for AM were evaluated in order to determine the diagnostic value of CT-findings were compared to operation, percutaneous drainage procedures and clinical course. In 15 patients the diagnosis of AM was established correctly by CT, 8 patients were reported normal. Diffuse infiltration of mediastinal fatty tissue was found in 3 patients, mediastinal fluid collections were demonstrated in 12 (infected hematomas = 4, abscess formation = 8). The extension of inflammatory changes could be exactly assessed by CT in all patients.

[Fibrous dysplasia: its appearance in the magnetic resonance tomogram]. / Fibröse Dysplasie: Erscheinungsbild im Magnetresonanztomogamm.

Eleven patients with proven fibrous dysplasia of the skeleton (FD) were examined using magnetic resonance imaging (MRI). Almost constantly T1-weighted hypointense, T2-weighted hyperintense (cystic) as well as T1- and T2-weighted hypointense (fibrous) areas within the lesion could be demonstrated, the latter of which always exhibited either moderate or marked enhancement following intravenous application of Gd-DTPA, resulting in a typical appearance. Furthermore, T1- and T2-weighted hyperintense areas within the lesion were seen in many patients due to focal hemorrhage. No linear time correlation between the clinical symptom pain and focal areas of hemorrhage as shown by MRI, could be established.

[Correlation of the x-ray morphology with the histopathological staging and grading of colorectal cancer]. / Korrelation der Röntgenmorphologie mit dem histopathologischen Staging und Grading kolorektaler Karzinome.

In a retrospective study stage grouping as well as histopathological grading (G category) of colorectal carcinomas was compared to radiographic findings at double contrast barium enema. A good correlation of tumour stage according to Dukes and the pT category and histopathological grading could be established to radiographic morphology. Apple core lesions and eccentrically obstructing neoplasms as well as saddle-like tumours exhibited worse staging and grading categories in comparison to polypoid lesions; plaque-like tumours are probably in between. It can therefore be assumed that the radiographic appearance of colorectal carcinomas may be a valuable tool to indicate stage group and G-category and thus offer information about patient prognosis.

[High-resolution CT of the lung versus thoracic radiography after adjuvant radiotherapy in breast carcinoma]. / HR-CT der Lunge versus Thoraxübersichtsaufnahme nach adjuvanter Strahlentherapie beim Mammakarzinom.

We examined the lungs of 35 women following postoperative radiotherapy for breast cancer by using high-resolution computed tomography (HR-CT). Radiotherapy was performed on a cobalt 60 unit using a five-field technique. The average interval between the end of radiotherapy and HR-CT examinations was 23.8 months. HR-CT was limited to those lung areas that were at risk for radiation-induced changes. In 40% of patients minimal interstitial damage (e.g. thickened septal lines, curvilinear densities) invisible on chest x-ray was demonstrated by HR-CT. Massive fibrosis as reported by others was not seen in our study. We conclude that in case lung involvement is suspected clinically during or after radiotherapy, HR-CT is the method of choice for demonstrating these morphological changes.

[MRI of the temporomandibular joint. Demonstrability and significance of the retro-articular vascular plexus]. / MRT des Kiefergelenks. Darstellbarkeit und Bedeutung des retroartikulären vaskulären Plexus.

The retro-articular vascular plexus of the temporomandibular joint (TMJ) is of great importance for the function of this joint. Aim of this study was to determine the amount of increase of signal intensity in the retro-articular vascular plexus after intravenous injection of contrast medium and to figure out potential advantages of this procedure. The posterior band of the articular disc--a landmark in the diagnosis of disc dislocations--becomes prominent after injection of contrast medium. Forty-five temporomandibular joints were studied before, and after intravenous injection of contrast medium with magnetic resonance imaging (MRI) using T1-weighted images in parasagittal plane. In all cases a measurable increase of signal intensity was demonstrable in healthy volunteers as well as in patients with normal or pathological TMJ findings. In 53.3% of cases the posterior band was better differentiable after administration of contrast medium. In patients with suspicion of pathological features in series without contrast medium, in 27.3% of those cases administration of contrast medium led to a more precise--"diagnostic"--evaluation of disc location. The study emphasizes the use of contrasts medium for evaluations of disc dislocation with MRI in cases of pathological or unclear findings in precontrast MRI series.

[The importance of magnetic field strength in the MR diagnosis of multiple sclerosis: a comparison of 0.5 and 1.5 T]. / Bedeutung der Magnetfeldstärke in der MR-Diagnostik der multiplen Sklerose: Ein Vergleich von 0.5 und 1.5T.

The value of magnetic resonance (MR) to establish the diagnosis of multiple sclerosis (MS) is well known. This study was undertaken to compare MR imaging of the brain of MS patients at high (1.5T) and mid (0.5T) field strength. 25 patients with MS underwent two consecutive MR studies within one hour, each consisting of axial proton density and T2-weighted spin-echo images. Lesions in the supratentorial white matter and corpus callosum and those in the brain stem and cerebellum were separately counted. At 1.5T significantly more lesions were seen than at 0.5T (p < 0.05). Although T2-weighted images at 1.5T added significant information compared to images obtained at 0.5T, in none of our 25 patients the diagnosis was missed at 0.5T. However, at 1.5T dissemination in space was better demonstrated, suggesting MR scanning with high field-units to be favourable in patients with clinically suspected MS.

[Diagnostic value of ultrasound in malignant melanoma]. / Der diagnostische Stellenwert des Ultraschalls beim malignen Melanom.

High-resolution real-time sonography enables visualisation of the morphology of the cutis and of cutaneous tumours. Evaluation of 26 malignant melanomas showed that there is a high degree of correlation between the sonographically measured values of maximal tumour thickness with those determined postoperatively by histometry. As malignant melanomas have very few internal echos, they can be easily differentiated from benign tumours. High-resolution sonography is thus the only diagnostic imaging method which helps to evaluate preoperatively malignant melanomas.

[Sonography of benign skin tumors]. / Sonographie bei benignen Hauttumoren.

Evaluation of 62 pigmented skin tumors of unknown pathology showed that benign and malignant tumors can easily be separated. Benign skin tumors have many internal echoes whereas malignant melanomas show an almost echo-free structure. Superficial spreading melanomas (SSM) and very flat benign tumors were both recorded as thin echogenic layers. It is not possible to differentiate them by US. Real time US is a simple non stressful, reproducible procedure that should be established as a routine diagnostic tool in dermatology.

[CT before and after liver transplantation]. / CT vor und nach Lebertransplantation.

In our retrospective study, we evaluated the role of CT in cases of liver transplantation. 118 examinations (37 pre- and 81 post-operative) were carried out in 46 transplant recipients. Pre-operatively CT was used to exclude retroperitoneal secondary lesions, although ultrasound was superior in the region of the porta hepatis. Patency of the portal vein can be established by means of duplex sonography and CT. Portography is indicated only in exceptional circumstances. Post-operative complications (abscesses, hematomas, infarcts) can be demonstrated by CT. CT-guided fine needle biopsies and percutaneous drainage can be carried out post-operatively, even under difficult conditions. Liver cell necrosis, if extensive, represents a serious risk to transplant survival. CT may clarify this, while other problems and differential diagnosis may be solved by angiography.

[Ultrasonic diagnosis following liver transplantation]. / Ultraschalldiagnostik nach Lebertransplantation.

Realtime and duplex sonography were used routinely for the postoperative and long-term follow-up of liver transplantation patients. In the early postoperative period 90 patients exhibited diffuse (67.7%) and focal (33.3%) alterations of the liver parenchyma; in 53% of patients various liquid lesions were diagnosed in the abdominal cavity. In case of diffuse alterations of the liver parenchyma, no correlation could be established between sonomorphology and histopathologic findings; especially rejection could not be diagnosed by using sonography. In case of focal intrahepatic lesions highly echogenic areas of infarction could be differentiated from poorly echogenic changes such as necrosis, haematoma and abscess--these entities had to be further distinguished by means of CT or needle biopsy. 20 patients showed biliary pathology (biliomas: 5, cholangiectasis: 15). In 73.3% of cholangiectasis the cause of obstruction could be demonstrated sonographically (biliary thrombus, stenosis of the anastomosis of the common bile duct, recurrence of tumour). In 13 patients major vascular complications were diagnosed predominantly by means of duplex sonography (hepatic artery occlusion: 4, hepatic artery stenosis: 1, portal vein occlusion: 1, partial thrombosis of portal vein: 2, portal vein stenosis: 2, stenosis with incomplete thrombosis of the inferior vena cava: 3, VCI stenosis: 1). 13 patients developed recurrent malignancy in the late postoperative period.

[Magnetic resonance tomography of the failed back surgery syndrome: a comparison with computed tomography]. / Magnetresonanztomographie beim "failed back surgery syndrome": Vergleich zur Computertomographie.

The term "failed back surgery syndrome" includes a variety of clinical-neurological symptoms following disc surgery. In a prospective study 18 patients suffering from monoradicular symptoms after disc surgery were examined by MRI and CT (both prior to and following intravenous application of contrast material). Findings were then compared to microsurgery. MRI produced correct diagnoses in 17 cases, CT in 13 cases. Recurrent disc herniation caused symptoms four times, and epidural scar formation twice. In twelve cases there was herniated disc material as well as an epidural scar present; disc material preponderated nine times, scar formation in three instances.

[Spondylitis: the clinical picture and follow-up assessment by magnetic resonance tomography]. / Spondylitis: Erscheinungsbild und Verlaufsbeurteilung mittels Magnetresonanztomographie.

MRI of proven spondylitis was performed in 39 patients. Acute spondylitis appeared hypointense on T1-weighted and hyperintense on T2-weighted images. Following intravenous application of Gd-DTPA, enhancement of the marrow and disk was seen. With progressive healing increasing signal was seen on T1-weighted images. This was caused by the presence of focal fat marrow representing the first sign of therapy response. Corresponding to the clinical healing process T1-signal increased due to fatty marrow, while the T2-signal decreased as well as the enhancement following Gd-DTPA application. Therefore, MR imaging can be recommended as the method of choice for early diagnosis of spondylitis and assessment of therapy response.

[Angiography following liver transplantation]. / Angiographie nach Lebertransplantation.

39 angiographic studies performed on 34 out of 150 patients following a total of 159 orthotopic liver transplantations until the year 1989 were reviewed in retrospect. All of the studies were carried out within a period of two months after transplantation (1-45 days). Angiographic techniques remain the "gold standard" for the assessment of vascular problems after liver transplantation. Arterial complications were seen in fourteen cases (8.8%); complications confined to the portal and inferior caval veins were found in six (3.8%) and twelve cases (7.5%), respectively. Angiography yielded normal postoperative findings in nine patients.

[Real-time sonography in the diagnosis and follow-up of malignant tongue tumors. I. Anatomic basis]. / Real-time-Sonographie in Diagnostik und Verlaufskontrolle maligner Zungentumoren. Teil I: Anatomische Grundlagen.

Normal structures of the tongue and floor of the mouth were studied using anatomic sections cut with a stainless steel band saw. The sections were performed on the same planes as used in US and CT scanning. The ultrasound studies were carried out with 20 young and healthy volunteers. CT images were obtained from head/neck preparations that were subsequently used for anatomic sectioning. On comparing these sections to US and CT images, normal structures including intrinsic and extrinsic tongue muscles, vessels and salivary glands were identified. Knowledge of the anatomic landmarks is mandatory for optimal US image reading.