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Biomedical subjects

R Forstner

Publications and source records attributed to R Forstner.

33 records · Page 2Linked to original sources
PubMed1995

Prostate cancer: effect of postbiopsy hemorrhage on interpretation of MR images.

PURPOSE: To assess the frequency of changes in signal intensity after prostatic biopsy and the effect of these changes on the magnetic resonance (MR) imaging staging of prostate cancer. MATERIALS AND METHODS: Seventy-three patients with biopsy-proved prostate cancer were divided into two groups according to time between biopsy and imaging (less than and more than 21 days). The findings at MR imaging were compared with those at pathologic examination. RESULTS: Postbiopsy hemorrhage was detected in 21 of 26 (81%) patients who underwent imaging less than 21 days after biopsy and in 23 of 47 (49%) patients who underwent imaging more than 21 days after biopsy (P < .01). Postbiopsy changes persisted for as long as 4 1/2 months. Less than 21 days after biopsy, there was a tendency to overestimate tumor presence and extracapsular extension. After 21 days, tumor presence was underestimated but the positive predictive value for extracapsular extension was improved. Staging accuracy less than 21 days after biopsy was 46%; this improved to 83% after 21 days (P < .01). CONCLUSION: Staging accuracy is significantly improved when imaging is deferred for 21 days after biopsy.

Biopsy, Needle↗
PubMed1995

Ovarian cancer recurrence: value of MR imaging.

PURPOSE: To assess magnetic resonance (MR) imaging in depiction of ovarian tumor recurrence and for identification of patients who may not benefit from surgical reexploration. MATERIALS AND METHODS: In a prospective study, 34 patients (mean age, 57.07 years) with surgically staged ovarian cancer underwent MR imaging before reexploration. Findings at MR imaging and surgery were correlated. MR imaging tumor depiction was correlated with tumor size, presence of ascites, and CA-125 levels. RESULTS: Tumor recurrence was identified in 29 patients at surgery. MR imaging depicted tumor in 20 patients. Accuracy for lesions smaller than 2 cm was 35% and increased to 82% for lesions larger than 2 cm (P < .01). MR imaging had low sensitivity for depiction of implants in the peritoneum and mesentery. Ascites improved depiction of smaller lesions (< 2 cm). MR imaging in combination with CA-125 levels improved detection of recurrent disease (CA-125 measurement alone 53% vs CA-125 measurement and MR imaging 75%, P = .048). CONCLUSION: MR imaging is a useful adjunct to the clinical examination to identify patients with recurrent disease and those in whom reexploration may not be beneficial.

Adult↗
PubMed1995

Ovarian cancer: staging with CT and MR imaging.

PURPOSE: To evaluate ovarian cancer staging and tumor resectability with computed tomography (CT) or magnetic resonance (MR) imaging. MATERIALS AND METHODS: Eighty-two women underwent CT (n = 43) or MR imaging (n = 50); eleven of these 82 underwent both. Imaging was performed within 4 weeks of surgical staging. Radiologic, surgical, and histopathologic findings were compared. RESULTS: Overall staging accuracy was similar for CT and MR imaging (77% [33 of 43] vs 78% [39 of 50]). Evaluation of pelvic cancer extent was better with MR imaging than with CT. There was no difference in detection of abdominal disease. Most mesenteric and small-bowel implants were not detected with either CT or MR imaging. For CT, the positive predictive value for cancer nonresectability was 100% (three of three patients); the negative predictive value was 92% (37 of 40 patients). The positive and negative predictive values for MR imaging were 91% (10 of 11 patients) and 97% (38 of 39 patients). CONCLUSION: While the staging accuracy of both CT and MR imaging is only moderate, prediction of tumor resectability is excellent.

Abdominal Neoplasms↗
PubMed1994

[Ultrasound detection of pneumoperitoneum based on typical ultrasound morphology].

The correspondence of sonography and radiography to figure out a pneumoperitoneum was studied in a group of 140 patients having undergone abdominal surgery. Sonography revealed 14 (82.4%) out of 17 radiographically positive patients. Because of the predominant collection of free air in the right upper quadrant, the ventrolateral liver surface represents the most important region in search of a pneumoperitoneum. In another 3 patients free peritoneal gas was diagnosed which was not revealed radiographically. The possibility to observe motion in real-time sonography repeatedly proved to be decisive for the certain diagnosis of free air (the shifting air under patient's movent and the immobility of the gas reflex under respiration). An observed "step" between the air in the costophrenic sinus and the abdominal gas reflex is considered to be an additional sonographic sign. These results justify combined evaluation of a suspected pneumoperitoneum by both plain film radiography and sonography prior to other imaging modalities.

Adolescent↗
PubMed1994

Congenital malformations of uterus and vagina.

Congenital malformations of uterus and vagina result from failure of development, failure of fusion or septal reabsorption of the Mullerian ducts. They present with a spectrum of findings ranging from agenesis to duplications. They are of clinical importance because of their association with menstrual disorders and impaired fertility. Furthermore, women with Mullerian duct anomalies (MDAs) have a significant risk of obstetric complications such as spontaneous abortion, stillbirth and preterm delivery. Hysterosalpingography (HSG) and laparoscopy have long played a pivotal role in the evaluation of MDAs. Ultrasonography and recently magnetic resonance imaging (MRI) have emerged as noninvasive modalities that are used complementarily or as alternative diagnostic tools. The radiographic findings according to the classification of Buttram and Gibbons are described for HSG, ultrasound and MRI. The advantages and limitations of each method are discussed, and finally an algorithm for imaging is recommended.

Diagnosis, Differential↗
PubMed1993

[Sonography of the lower urogenital system].

A suprapubic transvesical sonography of the lower urogenital tract performed by a radiologist is part of a complete investigation of the abdomen. The application of endosonographical methods is mainly subject-related in gynecology and obstetrics as well as in urology. The ranking rate of suprapubic transvesical sonography is compared with endosonographical methods, and, as indicated, also with CT und MRI. Concerning pathological-sonographical details, it is referred to the relevant literature. The diagnostic accuracy depends on the experience and ability of the investigator.

Female↗
PubMed1993

[Value of sonography in radiology--the retroperitoneum].

Ultrasonography ranks highly among the diagnostic methods of retroperitoneal pathologies. It has shown its practicability for the screening of non-organ-linked retroperitoneal lesions. However, ultrasonography has proven to be inferior to computed tomography concerning the overall accuracy. In this review, the value of ultrasonography in the imaging of non-organ-linked retroperitoneal lesions will be discussed.

Humans↗
PubMed1991

[Ultrasound image of the gallbladder fossa after cholecystectomy in the immediate postoperative period].

70 patients clinically classified as n.a.d. were sonographically examined for evaluation of the gallbladder fossa within two weeks after cholecystectomy. Four marked signs were noted. In 35 patients (50%) we found homogeneous echogenic formations of triangular, band-like, or oval shape in the bed of the gallbladder. In 25 cases (35.7%) inhomogeneous structures were seen. In 6 cases (8.5%) cystic structures resembling the normal gallbladder were seen which were interpreted as representing seromas or liquified haematomas. In 4 patients (5.7%) the bed of the gallbladder was entirely normal. Whether the gallbladder bed was closed by sutures or not, had no statistically significant effect on ultrasound appearance.

Cholecystectomy↗
PubMed1991

[MRT of bladder carcinoma: tumor staging and gadolinium contrast behavior].

33 patients with tumours of the urinary bladder were studied via MR, both with and without the paramagnetic contrast medium Gd-DTPA. Results were compared with the final pathological classification after TUER and bimanual palpation. The signal intensity ratio of tumour tissue/fat and tumour/muscle were calculated on T1 weighted images and after GD-DTPA and examined for their statistical significance. The increase in signal intensity of the tumours was statistically significant (Wilcoxon test p less than 0.01). There was no advantage for the T2 weighted images compared with Gd-contrasted enhanced T1 weighted images. MRI staging was correct in 28 out of 33 cases (accuracy 84.8%). Because of the relatively short acquisition time of T1 weighted images and the specific tumour enhancement, administration of Gd-DTPA proved to be of help in the staging of the carcinoma of the bladder. Two small tumours and regressive changes in central areas of tumours were recognised after Gd-DTPA.

Adult↗
PubMed1991

[Differential diagnosis of the "fat leg"--a case report].

This is a report about a patient, who came to our hospital because of a painful thickening of her left calf. She was treated with Heparin 48,000 IU/24 hours. A crural vein thrombosis was suspected. Instead of improvement of the symptoms the diameter of the leg grew until the state of a complete Compartment-syndrome. After exact inspection (Sonography, Computertomogramm) we found a hematom of the calf, caused by a rupture of the tibial part of the gastrocnemius muscle. Fasciotomies and evacuation of the blood brought a restitutio ad integrum. Diagnostic methods and faults are discussed.

Compartment Syndromes↗
PubMedDate not supplied

Imaging of ovarian cancer.

Cross sectional imaging continues to play an increasingly important role in ovarian cancer diagnosis, staging, and treatment follow-up. Screening for ovarian cancer remains a controversial subject. The combined use of clinical examination, CA-125, and endovaginal ultrasound (US) are being advocated for high risk patients but consensus recommendation for screening awaits further studies. In characterization of an ovarian neoplasm US is indisputedly the primary imaging approach. Only when US is inconclusive are further studies warranted. Magnetic resonance imaging (MRI) is generally preferred to computer tomography (CT). A prospective MRI-CT clinical trial has not been performed as yet. Preoperative staging by imaging is slowly gaining its acceptance. This is mostly due to the awareness of the difficulties and inaccuracy in surgical staging when unsuspected extensive disease is present. Furthermore, in known resectable ovarian cancer, primary chemotherapeutic cytoreduction may be a better treatment option. Accuracy of CT and MRI in staging ovarian cancer is similar, CT, however, is faster, more widely available, and less expensive; these are important attributes that are decisive in this time of health reimbursement constraints.

Female↗
PubMedDate not supplied

CT and MRI of ovarian cancer.

Among the gynecologic malignancies, ovarian cancer is second most common in incidence. However, unlike the other gynecologic cancers, its mortality has decreased only minimally during the last two decades [1]. Only recently, preliminary studies suggest promising results for ovarian cancer screening using transvaginal ultrasound in combination with serum Ca 125 levels [22,23]. Exploratory laparotomy has been the mainstay in the management of ovarian cancer, as it offers histopathological evaluation as well as cytoreduction. However, it is limited by its inaccuracy with understaging in 30-40% at initial presentation. Cross-sectional imaging contributes valuable information toward preoperative surgical and management planning. The proper surgical approach can be selected, the need for preoperative chemotherapeutic debulking can be assessed, and the surgeon will be forewarned of the need for assistance from a gynecologic oncologic surgeon or gastrointestinal oncologic surgeon if a complicated surgical procedure or bowel resection is indicated. CT is established as the primary imaging modality for characterization of ovarian tumors and ovarian cancer staging, while MR is emerging as a problem-solving modality. MR seems to be superior to CT in lesion characterization, in evaluation of local extent of tumor, and in tumor implants involving the hemidiaphragm and liver surface. The role of spiral CT has yet to be explored.

Adult↗
PubMedDate not supplied

Pelvic fistulas: appearances on MR images.

BACKGROUND: This multi-institutional study examines appearances of pelvic fistulas on magnetic resonance (MR) images. METHODS: MR images of 46 patients with documented fistulas from five teaching hospitals were retrospectively reviewed. All patients underwent T1-weighted (T1WI), T2-weighted (T2WI), and intravenous gadolinium chelate-enhanced T1-weighted (Gd-T1WI) images. Imaging sequences were separately and then collectively reviewed. The following determinations were made: fistula detection, fistula morphology and signal intensity, and the presence of associated abnormalities. Fistulas were classified into two categories: (1) fistulas that communicate with the bladder and (2) fistulas that do not communicate with the bladder. Fistulas within these two groups were subclassified further. The presence of fistulas was documented by surgery (five patients), endoscopy (six patients), fistulogram (20 patients), or physical exam (15 patients). RESULTS: Among the 46 patients, 53 fistulas were documented by means other than MR. Overall T1WI, T2W1 and Gd-T1WI images demonstrated 23, 31, and 39 of 53 fistulas, respectively. Gd-T1W1 detected significantly more fistulas than T1W1 (p < 0.05). Bladder fistulas were better shown on Gd-T1WI (8/15 fistulas) than on T1WI and T2WI (2/15 and 3/15) (p < 0. 05). Nonbladder fistulas were demonstrated by T1WI, T2WI, and Gd-T1WI images in 21, 28, and 31 of 38 fistulas, respectively. Among all fistulas, perianal fistulas (a subcategory of nonbladder fistula) had the highest detection by T1WI, T2WI, and Gd-T1WI in 19, 20 and 22 of 23 fistulas, respectively. On T1WI, 19 of 23 detected fistulas were low in signal intensity. On T2WI, 28 of 39 detected fistulas were high in signal intensity. On Gd-T1WI images, 29 of 40 fistulas were low in signal intensity, with enhanced tract wall. CONCLUSION: Bladder fistulas were best shown on Gd-T1WI, which was significantly greater than on T1WI or T2WI. Nonbladder fistulas were comparably shown by all techniques, with all performing modestly well. Perianal fistulas were shown equally well by all MR sequences and were the fistulas demonstrated with the highest sensitivity on MR images.

Adolescent↗
PubMedDate not supplied

MR imaging evaluation of renal cell carcinoma.

BACKGROUND: This study examines the minimally required imaging protocol needed for detection and staging of renal cell carcinoma (RCC). METHODS: In 81 patients (21 women, 60 men; mean age = 62 years) with 85 RCCs, T1-weighted (T1WI), contrast-enhanced T1-weighted (Gd-T1WI), T2-weighted (T2WI), and gradient recalled echo-fast low flip angle shot (GRE/FLASH) images were evaluated alone and in combination. Surgical-pathological findings were available in all patients and were considered the standard of reference. RESULTS: Tumor detection for lesions smaller than 3 cm was better on Gd-T1WI than on any other sequence, but only the comparison with noncontrast T1WI and GRE/FLASH was statistically significant (detection: T1WI = 33%, Gd-TIWI = 80%, T2WI = 60%, GRE = 47%). The respective accuracies of T1WI, Gd-T1WI, T2WI, and GRE/FLASH images were 81%, 78%, 71%, and 62% for evaluating local tumor extension; 90%, 88%, 89%, and 85% for lymphadenopathy; and 89%, 81%, 91%, and 95% for renal vein thrombus. The combination of T1WI and GRE sequences rendered the highest overall staging accuracy. CONCLUSION: For tumor detection, contrast-enhanced T1WI is necessary for lesions smaller than 3 cm. For tumor staging, although the addition of GRE results in significant improvement in the evaluation of venous thrombus, any combination of two sequences will result in similar accuracy, and the use of multiple sequences is not necessary.

Carcinoma, Renal Cell↗