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D M Panicek

Publications and source records attributed to D M Panicek.

At least 37 records · Page 2Linked to original sources
PubMed1997

Comparison of phased-array and body coils for MR imaging of liver.

AIMS AND OBJECTIVES: To compare liver lesion conspicuity using torso phased-array (TPA) and body coils with two pulse sequences. METHODS: Sixty patients with 125 focal hepatic lesions underwent T2-weighted fast spin-echo (T2-FSE) and fast multiplanar inversion recovery (FMPIR) imaging with a standard body coil and with a TPA coil. The first 30 patients were scanned identically in both coils with four acquisitions; the second 30 were scanned with four acquisitions in the body coil and two in the TPA coil. RESULTS: Liver-lesion contrast-to-noise (C/N) was significantly higher for the TPA coil both with four acquisitions (P< 0.001) and with two acquisitions (P < 0.002) using FMPIR, compared to with four acquisitions in the body coil. Liver-lesion C/N for T2-FSE was equivalent in both coils. Liver-lesion C/N was significantly higher (P<0.01) for FMPIR than T2-FSE both in the body coil and in the TPA coil. CONCLUSION: Liver-lesion C/N was significantly higher using the TPA coil rather than the body coil. Imaging time can be reduced by decreasing the number of acquisitions with the TPA coil.

Adult↗
PubMed1997

Magnetic resonance imaging of the postpneumonectomy chest: normal and abnormal findings.

To determine the normal findings at magnetic resonance imaging (MRI) of the postpneumonectomy space (PPS), and to evaluate the utility of MRI in detection of recurrent tumor in the postpneumonectomy chest, 32 MRI scans were performed in 31 patients at varying time intervals after pneumonectomy. Eleven patients also had 12 computed tomography (CT) scans performed at the same time to evaluate possible tumor recurrence. Of the 32 scans, 5 demonstrated complete obliteration of the fluid containing PPS, and 4 showed gas in the PPS; the remainder (n = 23) demonstrated persistence of fluid-filled spaces of varying size. The presence of a fibrotic rim of tissue was constant. In 11 patients with clinically suspected tumor recurrences, both CT and MRI were obtained: the two modalities performed with similar accuracy in diagnosing tumor recurrence at 16 sites; CT detected opposite-lung metastatic nodules not seen on MRI in one patient, and a rib metastasis described as "indeterminate" on MRI in a second patient. MRI detected a focus of recurrence in the PPS that was indeterminate on CT. There is considerable variability in the amount of fluid seen in the PPS on MRI. CT remains the procedure of choice for routine follow-up or in suspected tumor recurrence in the postpneumonectomy patient; MRI can be helpful if the CT scan is nondiagnostic or equivocal.

Adult↗
PubMed1997

CT and MR imaging in the local staging of primary malignant musculoskeletal neoplasms: Report of the Radiology Diagnostic Oncology Group.

PURPOSE: To assess the relative accuracies of computed tomography (CT) and magnetic resonance (MR) imaging in the local staging of primary malignant bone and soft-tissue tumors. MATERIALS AND METHODS: At four institutions, 367 eligible patients (aged 6-89 years) with malignant bone or soft-tissue neoplasms in selected anatomic sites were enrolled. Patients underwent both CT and MR imaging within 4 weeks before surgery. In each patient, CT scans were interpreted independently by two radiologists and MR images by two other radiologists at the enrolling institution. The CT and MR images were then interpreted together by two of those radiologists and subsequently reread at the other institutions. Imaging and histopathologic findings were compared and were supplemented when needed with surgical findings. Receiver operating characteristic curve analysis and descriptive statistical analysis were performed. RESULTS: Cases were analyzable in 316 patients: 183 had primary bone tumors; 133 had primary soft-tissue tumors. There was no statistically significant difference between CT and MR imaging in determining tumor involvement of muscle, bone, joints, or neurovascular structures. The combined interpretation of CT and MR images did not statistically significantly improve accuracy. Interreader variability was similar for both modalities. CONCLUSION: CT and MR imaging are equally accurate in the local staging of malignant bone and soft-tissue neoplasms in the specific anatomic sites studied.

Adolescent↗
PubMed1997

Soft-tissue sarcoma involving bone or neurovascular structures: MR imaging prognostic factors.

PURPOSE: To determine if magnetic resonance (MR) imaging findings of soft-tissue sarcoma involving bone or neurovascular structures allow prediction of local recurrence, distant metastasis, or disease-specific survival. MATERIALS AND METHODS: Preoperative MR images of 46 patients with soft-tissue sarcoma were reviewed for tumor involving bone or major vessels or nerves. MR imaging findings were correlated with local recurrence, distant metastasis, and disease-specific survival after surgery and chemotherapy and/or radiation therapy. Primary tumors were predominantly in the lower extremity (n = 35 [76%]), deep (n = 44 [96%]), and high-grade (n = 35 [76%]). RESULTS: On MR images, bone invasion occurred in 12 patients (26%), major-vessel encasement in five patients (11%), and major-nerve encasement in seven patients (15%). In patients with (n = 12) and those without (n = 34) bone invasion, frequencies of disease-related death (in nine [75%] and 12 [35%] patients, respectively) were significantly different (P = .02); frequencies of local recurrence or distant metastasis were not significantly different. In patients with and those without major-vessel or major-nerve encasement, there were no significant differences between frequencies of local recurrence, distant metastasis, or disease-specific survival. CONCLUSION: In soft-tissue sarcoma, bone invasion on MR images was predictive of decreased disease-specific survival. MR imaging findings of bone or neurovascular involvement otherwise appear to be more important for tailoring surgery than for predicting local recurrence, distant metastasis, or survival.

Bone Neoplasms↗
PubMed1997

Comparison of two algorithms and their associated charges when evaluating adrenal masses in patients with malignancies.

OBJECTIVE: This study was performed to compare two proposed algorithms used when evaluating an adrenal mass discovered during staging evaluation of a patient with a known malignancy. Such evaluation was meant to lead to determination of the relative charges associated with each algorithm. SUBJECTS AND METHODS: Fifty-four patients with known malignancies who required evaluation of an adrenal mass underwent both chemical shift imaging (CSI) and CT-guided for CSI. The hospital charges incurred for each procedure and any associated complications were normalized using national relative-value scale charges and conversion factors. A decision analysis was performed to compare the relative charges that would have been incurred if adrenal MR imaging had been performed in all patients, followed by CT-guided biopsy only in those patients with MR findings not diagnostic of adrenocortical adenoma, and the relative charges incurred if only CT-guided adrenal biopsy had been performed in every patient. RESULTS: Twenty-three (43%) of 54 adrenal masses were shown to be metastases by CT-guided biopsy. The sensitivity and specificity of CSI for the diagnosis of adrenocortical adenoma were 94% and 100%, respectively. The charges incurred by performing MR imaging as the initial examination with subsequent CT-guided biopsy only in those patients with CSI findings not diagnostic of adenoma would have been similar to those incurred by first performing CT-guided adrenal biopsy in every patient. CONCLUSION: CSI is an accurate, noninvasive technique for evaluating adrenal masses in patients with cancer. If CT-guided biopsy is used only when CSI is not diagnostic of adrenocortical adenoma, the associated charges would be virtually the same as when CT-guided biopsy is performed as the first test in every patient. Moreover, biopsies could have been avoided in 54% of these patients.

Adrenal Cortex Neoplasms↗
PubMed1996

Role of video-assisted thoracic surgery in the treatment of pulmonary metastases: results of a prospective trial.

BACKGROUND: A retrospective review revealed a 42% error rate between computed tomographic scan reports and thoracotomy findings; therefore, a prospective study was designed to compare the value of computed tomographic scans, video-assisted thoracoscopic exploration, and open thoracotomy in the management of pulmonary metastases. METHODS: Eligibility included any patient with only one or two ipsilateral pulmonary metastases identified on computed tomographic scan who was being considered for surgical resection. Initially video-assisted thoracic surgery was performed and all lesions identified were resected. A thoracotomy adequate for complete lung palpation was then carried out and any additional lesions found were removed. RESULTS: Eighteen patients of a planned 50 were treated before closure of the study. Four patients (22%) had no additional lesions found at thoracotomy. The primary sites of tumor were colon (10), breast (3), and one patient each skin (squamous), cervix, kidney, melanoma, and sarcoma. Four patients (22%) did have additional lesions at thoracotomy, which were benign. In the remaining 10 patients (56%) additional malignant lesions were found at thoracotomy after video-assisted thoracoscopic exploration. After 18 patients were entered, analysis of the early results disclosed a 56% failure rate of a computed tomographic scan and video-assisted thoracic surgery to detect all lesions. Being within the 95% confidence interval (32% to 78%), the study was abandoned. CONCLUSIONS: We conclude that video-assisted thoracic surgery should be used only as a diagnostic tool in managing lung metastasis. A thoracotomy is required to achieve complete resection, which is the major survival prognosticator for satisfactory long-term results.

Breast Neoplasms↗
PubMed1996

Collision tumors of the adrenal gland: demonstration and characterization at MR imaging.

PURPOSE: To evaluate the magnetic resonance (MR) imaging findings in collision tumors of the adrenal gland. MATERIALS AND METHODS: MR images obtained in 104 patients with a known primary malignant tumor and an adrenal mass were reviewed to find adrenal glands that contained two contiguous but histologically distinct masses. The findings in such cases were correlated with histopathologic findings. RESULTS: In two (2%) cases, both MR and histopathologic findings showed a mass within the adrenal gland that consisted of contiguous adrenal adenoma and metastasis, which represented a collision tumor. The adenomatous component in each tumor showed a (quantitative) decrease in signal intensity relative to that of the liver (79% and 61%) on opposed-phase images, whereas the metastatic component showed an increase in signal intensity (50% and 15%). Similarly, the adrenal lesion-to-spleen signal intensity ratio on opposed-phase images was lower for the adenomatous component in each (0.39 and 0.43) than for the metastatic component (1.17 and 0.90). CONCLUSION: MR imaging can demonstrate and enable characterization of the separate components of collision tumors within the adrenal gland. These findings can be crucial in planning and guiding subsequent percutaneous needle biopsy and patient care.

Adenoma↗
PubMed1995

Non-neoplastic causes of high signal intensity at T2-weighted MR imaging after treatment for musculoskeletal neoplasm.

OBJECTIVE: The objective of this study was to describe a variety of non-neoplastic causes of high-signal-intensity areas seen on T2-weighted magnetic resonance (MR) images obtained after treatment for malignant musculoskeletal neoplasm. DESIGN: MR examinations obtained after treatment for malignant musculoskeletal neoplasm in 11 patients were reviewed. The examinations of these patients were selected because at least one MR study of each patient showed high-signal-intensity areas on T2-weighted images at or near the site of the original tumor. The MR imaging findings were correlated with results of biopsy in four patients, and with information from follow-up radiologic examinations and the patients' medical records in all cases, to determine the cause of the high-signal-intensity areas. RESULTS: Non-neoplastic entities responsible for high-signal-intensity areas included postsurgical seroma, hematoma, postradiation therapy changes, fat necrosis and seroma, surgical hemostatic packing material, intercalary bone allograft, strut bone graft, atrophic muscle, and herniated colon and bladder. Knowledge of details of the surgical procedure and the time interval since surgery or irradiation aided in accurate interpretation of the findings, but did not allow immediate biopsy to be deferred in every case. CONCLUSION: High-signal-intensity areas on T2-weighted images in patients previously treated for malignant musculoskeletal neoplasm may represent a variety of entities other than residual or recurrent neoplasm, even in the presence of a mass. The MR imaging findings should be interpreted in conjunction with details of the specific clinical circumstances to prevent misdiagnosis and unnecessary biopsy.

Adolescent↗
PubMed1995

Correlation of the findings of thallium-201 chloride scans with those of other imaging modalities and histology following therapy in patients with bone and soft tissue sarcomas.

We performed a retrospective [corrected] study to evaluate the imaging potential of thallium-201 as compared with other imaging modalities in differentiating residual/recurrent tumors from post-therapy changes in patients with musculoskeletal sarcomas. 201Tl scans, magnetic resonance imaging (17), X-ray computed tomography (6) or contrast angiography (6) studies in 29 patients previously treated for musculoskeletal sarcomas were correlated with either histopathologic findings (26 patients) or 2-year clinical follow-up (three patients). All imaging studies were acquired within 2 weeks. Ratios of 201Tl tumor uptake to the contralateral (28 patients) or adjacent region of interest were calculated. When qualitative interpretation was in doubt, only those cases with a ratio of 1.5 or more were considered suggestive of recurrent of residual viable tumor tissue. Residual or recurrent tumor tissue was verified in 21 patients by biopsy. All had true-positive 201Tl scans while the other imaging modalities were true-positive in 20 and equivocal in one. In eight patients, there was no evidence of viable tumor tissue as proven by biopsy in five and long-term clinical follow-up in three. 201Tl scan was false-positive (ratio 1.5) in one patient and true-negative in seven while the other imaging modalities had four false-positives. The average 201Tl ratios were 2.8+/-1.1 in the true-positive cases and 1.3+/-0.3 in the true-negative cases. The percentage sensitivities, specificities, and accuracy for 201Tl were 100%, 87.5%, and 96.5% versus 95%, 50%, and 82.7% respectively for other imaging modalities. These results indicate that 201Tl scintigraphy is more accurate than other imaging modalities in differentiating residual/recurrent musculoskeletal sarcomas from post-therapy changes.

Adolescent↗
PubMed1995

Adrenal masses in patients with malignancy: prospective comparison of echo-planar, fast spin-echo, and chemical shift MR imaging.

PURPOSE: To assess echo-planar, fast spin-echo (SE), and chemical shift magnetic resonance (MR) imaging in differentiation of adrenal adenomas from malignant adrenal masses in patients with known malignancy. MATERIALS AND METHODS: Sixty-eight adrenal masses (23 malignant, 45 benign) in 68 patients with known malignancy were examined with echo-planar, fast SE with and without fat suppression, and chemical shift pulse sequences. RESULTS: With a cutoff T2 value of 75 msec, the sensitivity of echo-planar imaging for benign lesions was 82%, and specificity was 96%. With a cutoff adrenal mass-to-spleen signal intensity ratio of 0.80, the sensitivity of fast SE imaging for benign lesions was 53%, and specificity was 96%. With a cutoff adrenal mass-to-spleen ratio of 0.55, the sensitivity of chemical shift imaging for benign lesions was 80], and specificity was 100%. CONCLUSION: Chemical shift imaging and calculated T2 values from echo-planar imaging are promising techniques for differentiation of adrenal adenomas from malignant adrenal masses and can obviate biopsy.

Adenoma↗
PubMed1995

CT bone window photography in patients with cancer.

PURPOSE: To assess the utility of routinely photographing computed tomographic (CT) bone windows in patients with cancer. MATERIALS AND METHODS: The impression section of body CT reports were reviewed in 4,683 patients with cancer (2,240 female and 2,443 male patients, aged 2 months to 97 years [mean, 55 years]). RESULTS: The presence of definite or possible bone metastasis was mentioned in 523 (11.2%) patients. No prior radiologic examination was available in 165 patients. In the 358 patients who had undergone previous radiologic examinations, findings were positive in 271 and normal or indeterminate in 87. In 252 (5.4%) patients, CT with bone windows may have been needed for diagnosis of bone metastasis: 110 had extensive nonosseous metastases, 77 had no osseous metastasis, 19 had bone findings that were not followed up radiologically, and 46 had bone lesions that were new findings. These new lesions were visible on scans photographed at soft-tissue windows in 45 (97.8%) patients. CONCLUSION: Routine photography of CT bone windows is not necessary in patients with cancer.

Adolescent↗
PubMed1995

Echoplanar MR imaging for characterization of adrenal masses in patients with malignant neoplasms: preliminary evaluation of calculated T2 relaxation values.

OBJECTIVE: We undertook this study to assess the utility of echoplanar MR imaging for distinguishing benign from malignant adrenal masses in patients with known malignant neoplasms. MATERIALS AND METHODS: Thirty consecutive patients with 31 adrenal masses and a known malignant neoplasm underwent breath-hold echoplanar MR imaging with a repetition time of 6000 msec and four echo times (40, 80, 120, 160 msec) on a 1.5-T unit before biopsy. Subsequently, 10 masses were shown to be malignant at histologic examination, 12 masses were benign at histologic examination, and nine were thought to be benign because they had not changed in size at follow-up imaging. Mean lesion size was 2.4 +/- 2.1 cm. T2 calculations using regions of interest in the liver and adrenal mass were performed in each patient. RESULTS: The mean calculated T2 value of benign adrenal masses was 70.3 msec (SD, 11.6 msec) versus 104.6 msec (SD, 35.2 msec) for malignant adrenal masses (p = .013). Using a cutoff T2 value of 84 msec, 19 (90%) of 21 benign masses and nine (90%) of 10 malignant masses were correctly classified. The mean adrenal/liver T2 ratio was 1.4 (SD, 0.25) for benign lesions, and 2.1 (SD, 0.78) for malignant lesions (p = .017). Using a cutoff ratio of 1.60, 19 (90%) of 21 benign lesions and eight (80%) of 10 malignant lesions would have been correctly classified. CONCLUSION: This preliminary work suggests that obtaining T2 calculations from echoplanar MR images of adrenal masses is a useful technique for distinguishing benign from malignant adrenal masses in patients at risk for adrenal metastasis.

Adenoma↗