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Biomedical subjects

N A Mayr

Publications and source records attributed to N A Mayr.

At least 37 records · Page 2Linked to original sources
PubMed1996

Anatomic distribution of metastases in the vertebral body and modes of hematogenous spread.

STUDY DESIGN: A retrospective review of the magnetic resonance spine examinations of 49 patients with metastatic bone disease to the spine was performed. OBJECTIVES: To determine whether the pattern of metastatic distribution in the spine correlates with the type of primary tumor and theoretical mode of hematogenous spread by arterial or venous routes. SUMMARY OF BACKGROUND DATA: In 1940, Batson theorized a venous plexus route by which tumors spread to the spine from pelvic tumors such as prostatic carcinoma. It this theory is true, the venous vascular anatomy of the spine would result in metastases being deposited in the central or posterior vertebral body, whereas arterial deposits would occur near the end-plates. METHODS: Each vertebral body was divided into 27 equal cells in the magnetic resonance images; the central and posterior cells in the midsagittal view were defined as central, and the other cells were defined as peripheral. The primary tumor was assigned to either the arterial or venous group based on Batson's proposed mode of spread. The average number of lesions per involved vertebral body in the central and peripheral regions was calculated. RESULTS: There was no statistically significant correlation between tumors with proposed arterial/venous routes of metastasis and central/peripheral location of metastatic deposits. CONCLUSION: The mechanism by which tumors spread to the vertebral body may not be via a pure arterial or venous route. Other mechanisms such as tissue specificity, cascade system, and closed loop circulation system may be involved.

Adolescent↗
PubMed1996

Usefulness of tumor volumetry by magnetic resonance imaging in assessing response to radiation therapy in carcinoma of the uterine cervix.

PURPOSE: Clinical evaluation of tumor size in cervical cancer is often difficult, and clinical signs of radiation therapy failure may not be present until well after completion of treatment. The purpose of this study is to investigate early indicators of treatment response using magnetic resonance (MR) imaging for quantitative assessment of tumor volume and tumor regression rate before, during, and after radiation therapy. METHODS AND MATERIALS: Thirty-four patients with cervical cancer Stages IB [5], IIB [8], IIIA [1], IIIB [14], IVA [3], IVB [1], and recurrent [2] were studied prospectively with four serial MR examinations obtained at the start of radiation therapy, at 2-2.5 weeks (20-24 Gy), at 4-5 weeks (40-50 Gy), and 1-2 months after treatment completion. Tumor volume was assessed by three-dimensional volumetric measurements using T2-weighted images of each MR examination. The volume regression rate was generated based on the four sequential MR studies. These findings were correlated with local control, metastasis rate, and disease-free survival. Median follow-up was 18 months (range: 9-43 months). RESULTS: The tumor regression rate after a dose of 40-50 Gy correlated significantly with treatment outcome. The actuarial 2-year disease-free survival was 88.4% in patients with tumors regressing to < 20% of the initial volume compared with 45.4% in those with > or = 20% residual (p = 0.007). The incidence of local recurrence was 9.5% (2 out of 21) and 76.9% (10 out of 13), respectively (p < 0.001). Analysis by initial tumor volume showed that this observation was valid in patients with initial volumes between 40 and 100 cm3. Analysis by FIGO stage confirmed this observation in all patients except those with Stage IB. CONCLUSION: Sequential tumor volumetry using MR imaging appears to be a sensitive measure of the responsiveness of cervical cancer to irradiation. Treatment response can be assessed as early as during the course of radiation therapy by measurement of initial tumor volume and regression rate at 40-50 Gy. In patients with large (> 40 cm3) and advanced (Stage > or = IIIA) tumors, this technique may be helpful in supplementing the clinical examination for response assessment. The identification of patients at high risk for treatment failure may ultimately lead to improved clinical outcome.

Adult↗
PubMed1995

Postoperative radiation therapy in clinical stage I endometrial cancer: corpus, cervical, and lower uterine segment involvement--patterns of failure.

PURPOSE: To evaluate involvement of the lower uterine segment (LUS) in adenocarcinoma of the endometrium and to identify patterns of treatment failure. MATERIALS AND METHODS: Two hundred four patients, aged 29-92 years, with endometrial carcinoma underwent surgery. Postoperative radiation therapy was administered for adverse histologic criteria, including deep myometrial invasion, high grade, or LUS involvement. RESULTS: The incidence of tumor involvement of the LUS was 19%; of the cervix, 14%; and of the corpus, 67%. Distant metastasis occurred in 3% of patients with LUS involvement and in 17% of patients with cervical involvement. The local recurrence rate was 50% among patients with LUS involvement with no other risk factors and no postoperative radiation therapy and was 3% among those who underwent radiation therapy (P = .023). CONCLUSION: Early local-regional spread may be the primary mechanism of treatment failure in tumor invasion of the LUS. Aggressive local management, including postoperative radiation therapy, may be necessary.

Adenocarcinoma↗
PubMed1995

The effect of contrast dose, imaging time, and lesion size in the MR detection of intracerebral metastasis.

PURPOSE: To evaluate the effect of MR contrast dose versus delayed imaging time on the detection of metastatic brain lesions based on lesion size. METHODS: Contrast MR examinations with gadoteridol were obtained in 45 patients with brain metastases. The patients were divided into two groups: 16 received cumulative standard dose (0.1 mmol/kg) and 29 received cumulative triple dose (0.3 mmol/kg). Both groups were evaluated at two dose levels (lower dose and higher dose) with two separate injections. Each patient received an initial bolus injection of either 0.05 (cumulative standard dose) or 0.1 (cumulative triple dose) mmol/kg of gadoteridol to reach the lower-dose level and underwent imaging immediately and 10 and 20 minutes later. Thirty minutes after injection, an additional bolus injection of 0.05 (cumulative standard dose) or 0.2 (cumulative triple dose) mmol/kg was administered to reach the cumulative higher-dose level (cumulative standard dose, 0.1 mmol/kg; cumulative triple dose, 0.3 mmol). Images were acquired immediately. RESULTS: There was no difference in the detection rate for lesions larger than 10 mm among T2-weighted, lower-dose immediate and delayed, or immediate higher-dose images in both study groups. Lesions smaller than 10 mm had improved detection with delayed imaging in both study groups; however, the immediate higher-dose studies still had the highest detection rate. CONCLUSION: In the evaluation of small central nervous system metastases, either delayed imaging after the injection of standard contrast dose or higher contrast dose may improve their detection, and therefore affect clinical management. Higher contrast dose (cumulative triple dose) studies appear to be more effective than delayed imaging with standard dose.

Brain↗
PubMed1994

Brain parenchymal infection in bone marrow transplantation patients: CT and MR findings.

OBJECTIVE: The purpose of this study was to assess the MR and CT appearance of brain infection after bone marrow transplantation and to correlate the appearances with laboratory and pathologic findings. MATERIALS AND METHODS: We retrospectively reviewed the records of seven bone marrow transplant recipients with radiologic evidence of brain infection. RESULTS: Forty-one lesions were detected in seven patients with proved infectious foci outside the brain before brain infection was suspected clinically. Six patients had low total WBC or lymphocyte counts and one patient had normal total WBC and lymphocyte counts. Most lesions in patients with low total WBC or lymphocyte counts showed no appreciable edema or contrast enhancement. However, all lesions detected in the patient with normal total WBC and lymphocyte counts showed marked vasogenic edema and ring enhancement. CONCLUSION: Brain infection in bone marrow transplant recipients during immunosuppression exhibited MR characteristics different from those typically seen in immunocompetent patients. This appearance may be related to a diminished immunologic/inflammatory response.

Adult↗
PubMed1994

Delineation of gliomas with various doses of MR contrast material.

PURPOSE: To examine the effects of different gadolinium doses on the delineation of gliomas, particularly the demonstration of abnormal enhancement on T1-weighted images extending beyond the zone of apparent signal abnormality on corresponding T2-weighted images. METHODS: During phase II clinical trials of gadoteridol, 23 patients with pathologically proved gliomas were studied by MR with various doses of gadoteridol, ranging from 0.05 to 0.3 mmol/kg. RESULTS: All of the gliomas were readily detected by T2-weighted images. Twelve of 23 patients demonstrated enhancement on T1-weighted images extending beyond the zone of apparent signal abnormality demonstrated on T2-weighted images. These findings were seen in none of the six patients (0%) studied at 0.05 mmol/kg, one of five patients (20%) studied at 0.1 mmol/kg, four of five patients (80%) studied at 0.2 mmol/kg, and seven of seven patients (100%) studied at 0.3 mmol/kg. CONCLUSIONS: The detection of symptomatic gliomas does not require a contrast agent because they are generally large and readily demonstrated on T2-weighted images. However, the area of postcontrast enhancement of gliomas seems to be greater with higher doses of contrast agent. The cause of the abnormal enhancement extending beyond the zone of apparent signal abnormality on T2-weighted images seen in this limited study is unknown and probably represents tumor infiltration. The frequency of detection of such findings appears to be proportional to the dose of contrast material used.

Brain↗
PubMed1994

Phase III multicenter trial of high-dose gadoteridol in MR evaluation of brain metastases.

PURPOSE: To assess the efficacy and safety profile of high-dose (0.3 mmol/kg cumulative dose) gadoteridol in patients with suspected central nervous system metastatic disease. METHODS: We studied 67 patients using an incremental-dose technique. Patient monitoring included a medical history, physical examination, vital signs, and extensive laboratory tests within 24 hours before and after the MR examination. Precontrast T1- and T2-weighted spin-echo studies were performed, followed by intravenous injection of 0.1 mmol/kg of gadoteridol. T1-weighted images were acquired immediately after and at 10 and 20 minutes after injection. At 30 minutes an additional 0.2 mmol/kg of gadoteridol was administered (0.3-mmol/kg cumulative dose), and T1-weighted images were acquired. Cases demonstrating abnormal MR findings were assessed for efficacy by unblinded and blinded reviewers and were analyzed quantitatively. RESULTS: Three adverse effects in two patients were considered to be related to gadoteridol administration. No adverse effects were serious; all self-resolved. Forty-nine cases showed abnormal MR findings and were included in the efficacy analysis. A significantly greater number of lesions was seen on the high-dose as opposed to the standard-dose images. Blinded and unblinded readers identified 5 and 8 patients, respectively, with solitary lesions on standard-dose examination and multiple lesions on high-dose examination. Two patients who had normal standard-dose findings had lesions identified on high-dose studies. Quantitative analysis of 133 lesions in 45 patients demonstrated significant increases in lesion signal intensity on high-dose studies when compared with standard-dose studies. CONCLUSION: Gadoteridol can be safely administered up to a cumulative dose of 0.3 mmol/kg. High-dose contrast studies provide improved lesion detectability and additional diagnostic information over studies performed in the same patients with a 0.1-mmol/kg dose and aid in patient diagnosis and treatment. High-dose gadoteridol study may facilitate the care of patients with suspected central nervous system metastasis.

Adolescent↗
PubMed1994

Cost-effectiveness of high-dose MR contrast studies in the evaluation of brain metastases.

PURPOSE: To investigate the cost-effectiveness of high-dose MR contrast studies in the management of brain metastases. METHODS: During the phase III clinical trial of high-dose contrast studies (0.3 mmol/kg), 11 of 27 patients were judged by the reviewers to have potential treatment changes based on the additional information provided by the high-dose studies. We retrospectively evaluated how many of these 27 patients had actual treatment changes because of the results of the high-dose study. Using the fee schedule at our institution, the cost-effectiveness was analyzed based on the cost savings from treatment changes and the additional expense of implementing the high-dose studies. RESULTS: A total of 3 craniotomies ($22,800 each) and 2 aggressive courses of radiation therapy ($1122 each) were avoided in 4 patients because of the additional lesions detected by the high-dose studies. This resulted in a treatment cost savings of $70,644. The extra expense for implementing the high-dose study is $9126 for a single injection in all 27 patients, $9295 for 2 separate injections completed in 1 visit in the 11 patients, and $11,154 for 2 separate injections completed in 2 separate visits. The cost savings in management (diagnosis and treatment) therefore ranged from $59,490 to $61,518 for all patients and from $2203 to $2278 per patient. CONCLUSION: Based on our limited data, the high-dose study seems to impact positively on the cost-effectiveness in the management of brain metastases. However, because our study had limitations, our results need to be confirmed with a larger patient population and a more standardized treatment approach and fee schedule.

Adult↗
PubMed1993

Acute and late reactions to radiation therapy in patients with collagen vascular diseases.

BACKGROUND: A commonly held belief is that patients with collagen vascular diseases (CVD) have a greater risk of radiation therapy complications than patients without CVD. This impression is based on anecdotal reports, however. METHODS: A group of 61 patients with CVD were compared with a matched control group of 61 patients without CVD. The CVD group included 39 patients with rheumatoid arthritis (RA), 13 with systemic lupus erythematosus (SLE), 4 with systemic sclerosis (scleroderma) (SSc), 4 with dermatomyositis, and 1 with polymyositis. The control group was matched with respect to age, sex, tumor site and histologic characteristics, treatment aim, general treatment method, radiation therapy technique, site irradiated, radiation dose, date of treatment, and follow-up. RESULTS: Overall, there was no significant difference between the CVD and control groups in terms of acute (11% versus 7%, respectively) or late complications (10% versus 7%, respectively). This was also true when only patients who were treated definitively were considered. Furthermore, none of the patients treated palliatively had complications. Three patients in the CVD group had fatal complications, compared with none in the control group. RA was associated with a slight increase in late complications in the definitively treated patients, whereas SLE was associated with a slight increase in acute reactions. No significant acute or late reactions were observed in the patients with SSc, dermatomyositis, or polymyositis. CONCLUSIONS: In general, these differences are less than expected and not statistically significant. Consequently, from these data, the authors could not show a significant increase in radiation therapy complications for patients with CVD.

Adult↗
PubMed1993

Cervical cancer: application of MR imaging in radiation therapy.

PURPOSE: To evaluate magnetic resonance (MR) imaging in the planning of radiation therapy for patients with cervical cancer. MATERIALS AND METHODS: MR imaging was performed in 15 patients with predominantly advanced cervical carcinomas. Skin markings of the radiation ports were labeled with MR-detectable tubing and beads to assess the adequacy of port placement. Volume and extent of tumor at MR imaging were compared with those at physical and computed tomographic (CT) examinations. RESULTS: Tumor involvement of normal structures (parametrium, vagina, endometrium) was more extensive at MR imaging than at clinical examination in six patients (40%) and at CT in five patients (33%), resulting in modification of the radiation fields in eight patients (53%). Tumor size was larger on MR images than at clinical examination in 11 patients (73%). CONCLUSION: MR imaging can depict tumor volume and better delineate the extent of involvement than physical and CT examination. This can be useful for placement of radiation ports, especially when small boost fields are used.

Adult↗
PubMed1992

The application of contrast agents in the evaluation of neoplasms of the central nervous system.

Magnetic resonance evaluation of central nervous system neoplasms has improved tremendously since the introduction of gadolinium-based contrast agents. The optimal application of these agents in clinical imaging, however, has not been well established. The article discusses the recent application of these agents to a number of intracranial neoplasms, including metastases, gliomas, pituitary adenomas, and acoustic neurinomas/cerebellopontine angle tumors.

Brain Neoplasms↗
PubMed1991

Morphometric studies in intraductal breast carcinoma using computerized image analysis.

A morphometric study was performed using computerized image analysis on the histologic specimens of 26 patients with intraductal carcinoma of the breast and 26 normal control patients. A significant incidence of necrosis (56%) was observed in the breast ducts containing intraductal carcinoma. This was characterized by one or more areas of necrosis surrounded by a rim of viable tumor cells. The mean diameter of the ducts containing intraductal carcinoma was 349 microns compared with a mean diameter of 90 microns for the normal ducts. The mean diameter of the ducts containing necrosis was 470 microns compared with a mean diameter of 192 microns for the ducts containing a solid pattern of intraductal carcinoma. Central necrosis occurred in 94% of the ducts more than 180 microns in radius, whereas only 34% of the ducts less than 180 microns in size contained necrosis. The width of the viable neoplastic tissue was less than 180 microns in 91% of the ducts. These results are analogous to the findings of Thomlinson and Gray in human lung tumor cords and provide indirect evidence for the existence of a hypoxic compartment in intraductal carcinoma of the breast. This could be an explanation for the higher local failure rate after conservative surgery and irradiation for infiltrating cancers containing an extensive intraductal component.

Adult↗
PubMed1991

Magnetic resonance imaging of peripheral T-cell lymphoma.

We report magnetic resonance (MR) findings of two unusual cases of peripheral T-cell lymphoma, one initially presenting as a soft-tissue mass in the neck and the other in the foot. MR imaging provides better tissue contrast and lesion delineation than CT. However, MR signal characteristics cannot differentiate this lymphoma from other soft-tissue tumours. Although it is rare, peripheral T-cell lymphoma should be included in the differential diagnosis of a soft-tissue mass.

Foot↗
PubMed1990

The role of radiation therapy in the treatment of solitary plasmacytomas.

Between 1960 and 1985, 30 patients with solitary plasmacytomas were treated with radiotherapy at the University of Iowa: 13 patients with extramedullary plasmacytomas (EMP) and 17 with solitary plasmacytomas of bone (SPB). The local control rates were 92% for patients with EMP and 88% for those with SPB. Two of nine patients (22%) with EMP treated to the primary tumor only developed regional lymph node metastasis, indicating the need for elective irradiation of this area. The most common pattern of failure in both groups was progression to multiple myeloma. This occurred in 23% of the patients with EMP and 53% of those with SPB. The time course of progression to multiple myeloma differed for the two groups. All of those who progressed to multiple myeloma in the EMP group did so within 2 years, whereas a significant number of those in the SPB group progressed more than 5 years after initial therapy. None of five patients who received adjuvant chemotherapy in the SPB group progressed to multiple myeloma, compared to 75% (9/12) of the patients who did not receive chemotherapy.

Adult↗
PubMed1990

Intraductal breast carcinoma: initial results of a morphometric study using computerized digital image analysis.

Extensive ductal carcinoma in situ (DCIS) and necrosis in breast carcinoma have been correlated with a higher incidence of local recurrence in patients treated with breast-conserving surgery and radiotherapy. In an attempt quantitatively to assess duct size distribution and necrosis in DCIS, the authors devised a method utilizing computerized digital image analysis. The method and results of a pilot study comparing 21 patients with DCIS, and 21 normal breast specimens are presented. Normal breast tissue from autopsy material revealed a mean duct diameter of 90 microns, whereas the mean diameter of ducts in patients with DCIS was 359 microns (P less than 0.001). The presence of necrosis in DCIS correlated strongly with average duct size. Of the ducts larger than 360 microns in diameter 94% exhibited intraductal necrosis, whereas ducts less than 360 microns showed necrosis in only 30% of the measurements. Ducts with necrosis revealed a mean diameter of 498 microns versus 198 microns in ducts without necrosis (P less than 0.001). The authors suggest that necrosis develops in response to tumour cell hypoxia associated with cross-sectional duct expansion in DCIS. This growth pattern predisposing to tumour cell hypoxia could be a factor contributing to radioresistance and increased local recurrence.

Adult↗