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R Sigal

Publications and source records attributed to R Sigal.

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

[Intra-parotid neurogenic tumors of the facial nerve. Value of MRI].

Facial nerve intraparotid neuromas are rare. We report two cases with no facial paralysis. In the first case, the clinical protocol for the evaluation of a parotid mass did not suggest the intramastoid tumor extension. This extension was shown by CT and MRI and confirmed by gross and microscopic appearance. In the second case, no intrapretrous extension was observed with MRI. The diagnosis of neuroma was made during surgery. With a literature review, we discuss the diagnostic difficulties encountered in the investigation of parotid facial nerve tumors, emphasizing on the usefulness of CT and MRI in its diagnosis.

Adult↗
PubMed1996

Neoadjuvant chemotherapy with cisplatin-vindesine-5-fluorouracil and folinic acid for locally advanced head and neck carcinoma.

The aim of this study was to establish the feasibility, evaluate the response rate, and assess the impact on local control and survival in locally advanced (bulky nodal) squamous cell carcinoma of the head and neck (SCCHN) patients treated with neoadjuvant chemotherapy consisting of cisplatin followed by continuous infusion of vindesine and fluorouracil with intermittent i.v. folinic acid. Eligibility criteria included histologically proven SCCHN, previously untreated locally advanced stage III-IV with measurable or evaluable disease, no distant metastases, an Eastern Cooperative Oncology Group (ECOG) performance status of less than 2, patient age of at least 18 years, and adequate bone marrow, hepatic, and renal functions. The protocol consisted of three cycles (day 1, day 21, day 42) of Cisplatin (CDDP) 100 mg/m2/day i.v. on day 1 immediately followed by 4 days (96 h) of continuous infusion of vindesine 0.8 mg/m2/day and 5-fluorouracil (5-FU) 600-700 mg/m2/day with folinic acid 150 mg/m2 i.v. every 6 h x 16 doses before locoregional treatment with radiotherapy preceded by radical surgery when appropriate. Twenty-nine patients were enrolled in this study, and 28 were evaluable for activity; an objective response rate of 55% (four complete responses, 12 partial responses) was achieved. Leukopenia and mucositis were the most frequent and severe toxicities. The addition of vindesine did not improve the activity of the CDDP-FU-folinic acid combination, but this may be partly because of the particularly poor prognosis of the present patient population, with 75% of stage IV bulky nodal disease (N2c-N3).

Adult↗
PubMed1996

Radiologic assessment of intranodal vascularity in head and neck squamous cell carcinoma. Correlation with histologic vascular density.

RATIONALE AND OBJECTIVES: Nodal response to chemotherapy in head and neck squamous cell carcinoma depends on the vascularization. The authors assessed different techniques in detecting nodal vascularization. METHODS: Fourteen patients with head and neck tumor were included before surgical treatment. The largest metastatic lymph node (mean axial scanographic diameters 30 x 20 mm) was studied by color and pulsed Doppler, and dynamic magnetic resonance images, processed by factor analysis of medical image sequences (FAMIS), which estimates physiologic contrast enhancement kinetics (factors) and their spatial distributions (factor images). Results were compared with the histologic microvessel density (MVD). Using light microscopy, MVD was estimated by the vascular surface (by staining endothelial cells) to the stroma surface ratio x 100. RESULTS: Three factors were identified by FAMIS: a constant factor in necrosis, an earlier F1 factor and a later F2 factor in normal lymphoid areas and neoplastic stroma. Color flow signal was detected when the MVD was greater than 6.36. CONCLUSIONS: Only one model of vascularization was extracted by FAMIS, with no difference between neoplastic and spared lymphoid areas. The presence of color-flow signals could help predict the response of metastatic lymph nodes to chemotherapy.

Carcinoma, Squamous Cell↗
PubMed1996

CT and MR imaging of squamous cell carcinoma of the tongue and floor of the mouth.

Because contemporary treatment of oral cavity cancer involves procedures that spare the tongue and mandible, an adequate assessment of the oral cavity is essential for appropriate surgical and radiation therapy planning. Computed tomography (CT) and magnetic resonance (MR) imaging, which allow differentiation between soft tissues, are valuable tools for assessing this complex region. Their main advantage resides in their capacity to show at best the normal anatomy and the exact extent of a low-lying tumor. For display of soft tissues and tumor, MR imaging, being a multiplanar and multicontrast technique, is superior to CT. Nonenhanced T1-weighted MR imaging is better for defining the exact extent of medullary bone invasion, which appears as a low-signal-intensity area within hyperintense medullary fat. CT is optimal in detection of cortical bone invasion, which appears as an interruption or erosion of the peripheral hyperattenuating rim. Thus, in cancer of the tongue, MR imaging should be performed first. If tumor extension to the mandible is suspected (due to clinical or MR imaging findings), CT should be added. In cancer of the floor of the mouth, both MR imaging and CT should be performed in the initial work-up, especially in those cases in which there is a clinical doubt about mandibular extension of disease. The main drawback of both modalities is their lack of specificity; other methods are needed to discriminate between tumors and inflammatory or infectious diseases, particularly in the mandible. However, once the diagnosis has been confirmed histologically, treatment can be chosen based on complementary information obtained from CT and MR imaging.

Carcinoma, Squamous Cell↗
PubMed1996

Oral cavity, oropharynx, and salivary glands.

In the oral cavity and oropharynx, the predominant disease is cancer, which arises, in most cases, from the oral mucosa. Therefore, radiologists have a minor role in the detection of the disease but help to define the exact extent of the lesion and have an important role in therapeutic planning. Computed tomography and magnetic resonance imaging are the imaging modalities of choice. In the salivary glands, nonmodalities are numerous and include computed tomography, magnetic resonance imaging, sialography, sonography, and scintigraphy. The role of radiologists is to select the best study to determine the nature of the lesion and its extent and consequences. The choice of first study is primarily based on physical examination.

Humans↗
PubMed1995

Cerebral vasculitis after interleukin-2 therapy for renal cell carcinoma.

We report one patient with paralysis of the right upper extremity, bilateral cerebellar syndrome, and cognitive changes after treatment with interleukin-2 for metastatic renal cell carcinoma. Focal neurologic disturbances were associated with multiple images of cerebral infarcts but also with extraneurologic signs and autoantibodies. We suggest that this is a case of cerebral vasculitis with an autoimmune mechanism triggered by interleukin-2 therapy.

Adult↗
PubMed1995

High resolution T1 weighted magnetic resonance imaging of the deep brain structures using a reduced bandwidth.

High spatial resolution T1 weighted images of the brain were acquired in 5-13 min on a whole-body magnetic resonance imager operating at 1.5 T. In order to obtain 5-8 cm field of view images, the receiver bandwidth (Bw) was lowered to 2 kHz. The use of a 2 kHz Bw, instead of the standard 16 kHz Bw, partially compensated the signal loss due to the small pixel size by increasing the signal-to-noise ratio, without scan time penalty. The chemical shift artifact associated with reduced Bw was not observed because fat signal is negligible in the brain.

Brain↗
PubMed1994

Head and neck rhabdomyosarcomas in children: value of clinical and CT findings in the detection of loco-regional relapses.

Between 1984 and 1990, 16 children who had been treated for a histologically proven head and neck rhabdomyosarcoma developed 19 local recurrences. Fourteen relapses discovered in 11 children (group 1) were based on clinical data acquired 3 to 52 months after completion of treatment. Clinical symptoms (12 patients) or examination (2 patients) led to suspicion of a relapse. The clinical presentation of relapses and that of primary tumour were identical in eight cases. CT scans performed prior to recurrence revealed a stable 'post-therapeutic residue' without mass effect at the original site (12 patients) or was normal (2 patients). Six of these 11 children died at 1 to 15 months and five are alive 12 to 36 months after treatment of recurrence. Five relapses were discovered on CT studies 3 to 15 months after completion of treatment in the remaining five children (group 2). Clinical examination was normal in all cases. CT scans performed 3 months before recurrence showed a stable 'post-therapeutic residue' (4 patients) or was normal (1 patient). All of these five children died 3 to 23 months after the relapse.

Adolescent↗
PubMed1994

Factor analysis of medical image sequences in MR of head and neck tumors.

PURPOSE: To evaluate factor analysis of medical image sequences (FAMIS), a means whereby physiologic contrast enhancement kinetics, called factors, and their spatial distribution, termed factor images, are estimated after acquisition of dynamic MR images. The method is intended to recognize and characterize the different tissue kinetics automatically. METHODS: This method was evaluated in a series of 22 patients with head and neck tumors. Eleven patients presented with a previously untreated lesion. Six were examined for tumor recurrence, previously treated by multiple therapies. Five patients had preoperative chemotherapy and underwent MR before and after chemotherapy. In all cases, MR images were correlated with surgical and pathologic data. MR examinations were performed on a 1.5-T unit with static sequences and dynamic sequences acquired after bolus injection of gadolinium and processed by FAMIS. RESULTS: FAMIS was able to identify three factors representing contrast-enhancement kinetics and their associated factor images. The neoplastic component was associated with the earlier factor image, F1. Fibrosis and chemotherapy and/or radiation-induced changes were associated with the two later factors, F2 and F3. The limits of this method were highly vascularized tissues whose earlier factor was similar to that of neoplastic tissues (mucosae and salivary glands), patient motion, responsible for artifacts in FAMIS, and lesions of less than 5 mm. CONCLUSION: FAMIS of dynamic MR studies was useful for differentiating neoplastic tissue from tissue having undergone changes by chemotherapy and/or radiotherapy, but it did not improve the ability of MR to characterize neoplastic tissues in previously untreated patients.

Adult↗
PubMed1994

A technique of measuring the precision of an MR-guided stereotaxic installation using anatomic specimens.

PURPOSE: To develop a method for direct measurement, using anatomic specimens, of the precision of MR-guided stereotaxic location and to describe its application to a 1.5-T MR unit with a Leksell stereotaxic frame. METHODS: Small pieces of gelfoam (1 X 1 X 1 mm), soaked in gadopentetate dimeglumine, were stereotaxically introduced into formalin-fixed human heads using a Leksell D (three experiments) or G (nine experiments) stereotaxic frame. The head and the frame were then introduced into a 1.5-T MR unit. The target coordinates (as set on the stereotaxic frame by one investigator) were then compared with the MR-determined stereotaxic coordinates (calculated independently by another investigator). The imprecisions Ex, Ey, and Ez in each direction were defined as the differences between the calculated and the chosen coordinates. RESULTS: Regarding the three targets studied with the D frame, mean imprecision Ex was 1.08 +/- 0.50 mm (mean +/- SEM), Ey 0.83 +/- 0.58 mm, and Ez 0.75 +/- 0.25 mm. For the nine targets studied with the G frame, Ex was 0.48 +/- 0.17 mm, Ey 0.69 +/- 0.14 mm, and Ez 0.82 +/- 0.13 mm. Statistical analysis of the results showed no significant difference between Ex or Ey and half the size of a pixel, indicating that, in the axial plane, stereotaxic MR precision is limited only by pixel size. A statistically significant difference was observed in the coronal plane between Ez and half the size of a pixel, but it must be stressed that Ez remained smaller than 1 mm. CONCLUSION: MR-guided stereotaxic location can be used with confidence for most diagnostic, functional, and therapeutic procedures.

Calibration↗
PubMed1993

Oxygenation of head and neck tumors.

BACKGROUND: Tumor hypoxia could play a role in the response to radiation therapy. Few data are available on oxygen tension (pO2) measurements in head and neck tumors. METHODS: The KIMOC-6650 Histograph (Eppendorf, Hamburg, Germany) was used to measure the oxygenation status of normal tissues and head and neck tumors in 20 patients. RESULTS: The median pO2 for normal tissues was 43 mmHg with very low pO2 values (2.0 mmHg or less) recorded in two patients. Low median pO2 levels (10 mmHg or less) were recorded in 2 of 5 primary tumors and in 11 of 15 metastatic lymphadenopathies, with very low values in 11 nodes. The median pO2 in tumors was lower than that of normal tissues in 12 of 15 patients with comparative measurements. Oxygen tension was recorded in three nodes after an evaluation of tissue density (by computed tomographic scanner); in two nodes, the mean and median pO2 values were lower in the hypodense areas than in isodense areas. The data for N2 and N3 nodes showed significantly more values below 2.0 mmHg as nodal size increased (P < 10(-4), by chi-square test). No systematic decrease in pO2 was recorded from the periphery to the center of the tumors. CONCLUSIONS: Very low pO2 values, corresponding to radiobiologic hypoxia, were found in most of these tumors. The prognostic value of these pO2 measurements in regard to treatment response remains to be demonstrated.

Adult↗
PubMed1993

Aggressive fibrous dysplasia of the maxillary sinus.

Fibrous dysplasia is usually a slowly progressive, benign disease that develops over several years and presents with deformity or mild symptomatology. Five of 34 patients (ages 4-21 years), who were subsequently diagnosed histologically as having fibrous dysplasia of the maxillary sinus, rapidly developed soft tissue masses of the malar region over a period of less than 4 months with accompanying pain (2 patients) and nasal obstruction and exophthalmos (2 patients). Each was clinically suspected of having a sarcoma; two had been thought to have an "osteofibrosarcoma" on initial biopsy at outside hospitals. After resection, all lesions developed regrowth. At histopathologic examination, both initial and recurrent masses proved to be typical fibrous dysplasia with spicules of woven bone in cellular, sometimes vascular, fibrous tissue. No malignant degeneration was found. On conventional radiography, aggressive fibrous dysplasia produced opacification and expansion of the maxillary sinus and apparent disruption of its wall with an associated soft tissue mass. Computed tomography (CT) demonstrated voluminous heterogeneous masses with "ground glass appearance", calcifications, areas of enhancement, low attenuation, cystic areas, and a thinned, sometimes interrupted, maxillary wall. Despite the aggressive clinical course for both initial and recurrent lesions, the CT findings of a "ground glass" mass with calcifications surrounded by a maxillary sinus wall, even if incomplete, can suggest the diagnosis of aggressive fibrous dysplasia.

Adolescent↗
PubMed1992

Adenoid cystic carcinoma of the head and neck: evaluation with MR imaging and clinical-pathologic correlation in 27 patients.

Twenty-seven adenoid cystic carcinomas (ACCs) of the head and neck in 27 patients were evaluated in a retrospective study based on findings at magnetic resonance (MR) imaging and pathologic and clinical examination. Clinical follow-up was obtained over a mean period of 6.3 years (range of follow-up, 3 months to 17 years); all patients underwent one to seven MR examinations. On T2-weighted images, lesions with low signal intensity corresponded to highly cellular tumors (solid subtype) with a poor prognosis; lesions with high signal intensity corresponded to less cellular tumors (cribriform or tubular subtype) with a better prognosis. MR images were not specific in differentiation of ACCs from other types of tumors; this result underscores the need for biopsy to ensure correct diagnosis. Local, intracranial, osseous, and perineural invasion was depicted, but because of its lack of specificity, MR imaging caused overdiagnosis of tumor extension, particularly perineural spread and bone abnormalities.

Adolescent↗