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C Peterfy

Publications and source records attributed to C Peterfy.

32 records · Page 2Linked to original sources
PubMed1998

High resolution MRI of small joints: impact of spatial resolution on diagnostic performance and SNR.

This study focuses on the spatial resolution required for cartilage imaging. The purposes of this study were (I) to analyze the diagnostic performance in diagnosing artificially produced cartilage lesions in a small joint model using an optimized fat saturated three-dimensional gradient-echo sequence, (II) to relate the lesion size and depth as diagnosed in the magnetic resonance images with the corresponding pathologic findings and (III) to assess signal-to-noise (SNR) ratios for each of the protocols. Twenty-five artificial cartilage lesions were created in the knee joints of 10 rabbits. These specimens and seven specimens without lesions were imaged at 1.5 T using a three-dimensional gradient-echo sequence with varying slice thickness, field of view and matrix. A total of 404 corresponding images were selected, 50% with and 50% without cartilage lesions. Six radiologists scored all images according to five levels of confidence and receiver operating characteristic (ROC) analysis was performed. Lesion size and depth were compared to the corresponding pathological specimen sections. Additionally SNR ratios were calculated. ROC analysis of pooled data from all readers showed the highest area under the ROC curve for the sequence with the highest spatial resolution, while the diagnostic performance was significantly lower in the other sequences (p <0.01). Assessment of the lesion size and depth was correct in 45% and 40% respectively with the highest resolution and in 29% and 23% with the lowest resolution. SNR ratios decreased with increasing spatial resolution. In conclusion this study shows that increasing spatial resolution improves diagnostic performance in cartilage lesions, though SNR decreases substantially. Assessment of correct lesion size and depth still is limited.

Animals↗
PubMed1997

Artificially produced cartilage lesions in small joints: detection with optimized MRI-sequences.

The purpose of this study was to evaluate different magnetic resonance imaging (MRI) pulse sequences in the detection of artificial cartilage lesions in small joints using an animal model. A total of 32 artificial cartilage lesions were created in the knee joints of 20 rabbits. Twenty lesions were produced 4 weeks and 12 lesions 1 h before the MRI examination, performed in an extremity coil at 1.0 T. All joints were examined with five imaging sequences: (1) a conventional T1-weighted spin-echo (SE)-sequence (repetition time [TR] 600 ms, echo time [TE] 15 ms), (2) a T2-weighted turbo-SE-sequence (TR 2000 ms, TE 85 ms), (3) a two-dimensional (2D) gradient echo (GE)-sequence (TR 440 ms, TE 10 ms, flip angle 60 degrees) and (4,5) two three-dimensional (3D) GE-sequences (TR 40 ms, TE 7 ms, flip angle 40 degrees, with fat suppression (FS) and TR 30 ms, TE 9 ms, flip angle 40 degrees). Two examinations had to be excluded because of insufficient image quality and the remaining examinations were analyzed by two experienced radiologists. The MRI images were correlated with the pathologic findings and anatomical structures were scored according to a 5-level scale. Direct comparison of the pathological and MRI findings showed that 19 of the 30 artificially induced cartilage lesions were detected with the FS 3D GE-sequence, 13 with the 2D GE-sequence, 11 with the 3D GE-sequence, 3 with the T1-weighted SE-sequence, and 2 with the T1-weighted SE-sequence. The highest percentage of artificial cartilage lesions was demonstrated using a fat-suppressed 3D GE-sequence. However, the analysis of cartilage defects in small joints with optimized sequences as well as clinical routine hardware and software had limitations. Therefore a pilot study was performed analyzing newly developed high resolution FS 3D GE images obtained from 5 rabbit knees with 10 cartilage lesions at 1.5 T. Two sequences were used with 1.0 and 0.5 mm slice thickness, a matrix of 256 x 256 and 512 x 256 and a field of view of 12 x 6 and 8 x 6 cm. In this small subset detection rates were substantially higher than in the 30 rabbit knees examined before.

Animals↗
PubMed1995

Musculoskeletal neoplasm: perineoplastic edema versus tumor on dynamic postcontrast MR images with spatial mapping of instantaneous enhancement rates.

PURPOSE: To evaluate the utility of fast, contrast-enhanced, sequential magnetic resonance (MR) imaging in differentiating between extraosseous tumor and perineoplastic edema. MATERIALS AND METHODS: Fourteen patients underwent sequential MR imaging (3.5 seconds per image) after bolus administration of gadopentetate dimeglumine. Initial rates of enhancement (initial slope) were calculated on a pixel-by-pixel basis and displayed as a "slope image"' in which pixel intensity reflected the slope value. Close correlation with wedge biopsy specimens was performed. RESULTS: Mean initial slope values were viable extraosseous tumor, 9.33 (standard deviation, 2.23); infiltrated muscle, 9.07 (2.31); edematous muscle without tumor infiltration, 5.48 (1.27); normal muscle, 1.11 (0.65). Differences in initial slope between all neoplastic and nonneoplastic tissues were statistically significant. Within individual patients, initial slope of edematous muscle was always 20% or more lower than that of neoplastic tissue. Slope images highlighted areas of viable extraosseous tumor and infiltrated muscle against edematous and normal tissues. CONCLUSION: Computer-generated slope images derived from sequential postcontrast MR images allow differentiation between tumor and nonneoplastic edema and may thereby guide the surgeon in planning limb-sparing procedures.

Adolescent↗
PubMed1995

Primary bone tumors: value of MR angiography for preoperative planning and monitoring response to chemotherapy.

OBJECTIVE: The purposes of our study were to investigate the use of MR angiography with two- (2D) and three-dimensional (3D) displays in evaluating vascular morphology of musculoskeletal neoplasms for preoperative planning of limb-salvage surgery and to assess the use of MR angiography for monitoring changes in neovascularity and evaluating response to chemotherapy. SUBJECTS AND METHODS: We used MR angiography (2D time-of-flight) to study 13 patients with primary bone tumors (nine osteogenic sarcomas, two Ewing's sarcomas, and two primary lymphomas of bone) at the time of initial presentation. Eight patients (all of whom had osteogenic sarcoma) also underwent MR angiography following chemotherapy before limb-salvage surgery. Two-dimensional maximum intensity projections were obtained. Three-dimensional reconstructions of vascular structures were created from the angiographic source images and were displayed simultaneously with 3D reconstructions of tumor and normal bone generated from conventional MR images. RESULTS: Two-dimensional maximum intensity projections were useful for evaluating small vessel neovascularity; 3D displays demonstrated spatial relationships of tumor, feeder vessels, and normal vascular structures. Tumor encroachment onto or encasement of normal vascular structures was shown in four patients on 2D maximum intensity projections and on 3D displays. The eight patients with osteogenic sarcoma who had follow-up imaging showed marked neovascularity prior to chemotherapy. Five patients responded to chemotherapy (> or = 90% tumor necrosis at histology); MR angiography showed marked reduction in tumor neovascularity in these patients. Three patients did not respond to chemotherapy; MR angiography showed unchanged neovascularity in one and increased neovascularity in two of these patients. CONCLUSION: MR angiography provides good visualization of peripheral vascular branches and tumor neovascularity in patients with primary bone tumors. MR angiography demonstrates encroachment onto and encasement of major vessels by the tumor mass and appears to be useful for assessing response to chemotherapy in osteogenic sarcoma and possibly other primary bone tumors by detecting treatment-induced changes in tumor neovascularity.

Adolescent↗
PubMed1995

[CT and MRI in elastofibroma. A rare, benign soft tissue tumor].

Elastofibroma is a rare, benign soft-tissue tumor that occurs along the chest wall in the periscapular region. We identified five patients with a surgical diagnosis of elastofibroma who had had CT and/or MR scans. CT and MR imaging were compared to histologic findings in two patients. CT was available in three patients and demonstrated periscapular soft-tissue tumor with an attenuation similar to that of adjacent muscle. In one patient, the tumors appeared homogeneous. In two patients, the tumor showed strands of low density similar to that of adjacent subcutaneous fat on CT. On MR imaging, all five tumors showed predominantly low-signal intensity on both T1 and T2-weighted images. The tumors contained focal areas with high-signal intensity on T1-weighted scans that showed intermediate to high-signal intensity with T2-weighting. The areas of low-signal intensity on both T1 and T2-weighted images corresponded histologically to fibroelastic tissue. The areas of high signal intensity on T1-weighting and intermediate to high-signal intensity on T2-weighting reflected focal areas of fat within the tumor. Although CT and MR imaging findings are not specific, the presence of a soft-tissue tumor along the chest wall in a periscapular location that shows predominantly low intensity on all sequences reflecting fibrous tissue with interspersed focal areas of fatty tissue is highly suggestive of elastofibroma.

Aged↗
PubMed1994

MR diagnosis of complete tears of the anterior cruciate ligament of the knee: importance of anterior subluxation of the tibia.

OBJECTIVE: The primary role of the anterior cruciate ligament is to resist anterior subluxation of the tibia. When the ligament is torn, the tibia is free to sublux anteriorly when the leg is pulled forward. In addition to visualizing the anterior cruciate ligament directly, MR imaging can show joint alignment. The purpose of this study was to test the efficacy of MR images of anterior subluxation of the tibia for diagnosing complete tears of the anterior cruciate ligament. MATERIALS AND METHODS: We evaluated the records of 120 consecutive patients who underwent MR imaging of the knee and subsequently had arthroscopy. Arthroscopy showed a complete tear of the anterior cruciate ligament in 21 patients, a partial tear in eight patients, and an intact anterior cruciate ligament in 91 patients. Two radiologists together reviewed the MR images, and interpretation of anterior cruciate ligament integrity was reached by consensus. The anterior cruciate ligament was categorized as intact, completely torn, or partially torn on the basis of conventional MR imaging criteria. The degree of anterior subluxation of the tibia was measured on a separate occasion in random order by a radiologist who used a sagittal section through the middle of the lateral femoral condyle. On the selected image, two vertical lines parallel to the left and right margins of the image frame were drawn tangent to the posterior cortical margins of the lateral femoral and tibial condyles. Anterior subluxation of the tibia was determined by the distance in millimeters between these two lines and measured with calipers by using the 5-cm scale on the images. Measurements were considered reliable only to one half of the smallest increment of this scale (i.e., 5 mm). Accordingly, tibial subluxation (x) was measured in 5-mm increments, with x < or = 0 mm designated grade 0, 0 mm < x < or = 5 mm designated grade 1, 5 mm < x < or = 10 mm designated grade 2, and so forth. RESULTS: Conventional MR imaging criteria had 90% sensitivity and 94% specificity for diagnosing complete tears of the anterior cruciate ligament. According to the receiver-operating-characteristic (ROC) curve, anterior subluxation of the tibia greater than 5 mm (grade 2 or greater) was considered to be the optimal threshold (sensitivity, 86%; specificity, 99%) for diagnosing complete tears of the anterior cruciate ligament. Notably, none of the six false-positive diagnoses of complete tears by conventional criteria (three partial tears and three intact ligaments at arthroscopy) were misdiagnosed when tibial subluxation was used as the diagnostic criterion. Subluxation greater than 5 mm can be falsely negative with chronic tears of the anterior cruciate ligament (n = 2) or when a displaced bucket-handle tear of the lateral meniscus blocks anterior subluxation of the tibia (n = 1). CONCLUSION: An anterior tibial subluxation greater than 5 mm (grade 2 or greater) is a simple objective measurement that serves as a helpful adjunctive sign in the diagnosis of complete tears of the anterior cruciate ligament. This sign also offers improved discrimination of complete from partial tears of the anterior cruciate ligament.

Adult↗
PubMed1993

Hematopoietic bone marrow in the adult knee: spin-echo and opposed-phase gradient-echo MR imaging.

Hematopoietic bone marrow in the distal femur of the adult may be mistaken for a pathologic marrow process in magnetic resonance imaging of the knee. We investigated the incidence of hematopoietic marrow in the distal femur in a series of 51 adult patients and compared spin-echo (TR/TE in ms: 500/35, 2000/80) and opposed-phase gradient-echo (0.35 T, TR/TE in ms: 1000/30, theta = 75 degrees) magnetic resonance images. Zones with intermediate to low signal intensity on T1-weighted spin-echo and opposed-phase gradient-echo sequences representing hematopoietic marrow within high signal intensity fatty marrow were observed in 18 of the 51 patients. Five patterns of marrow signal reduction were identified; type 0: uniform high signal, i.e., no signal change; type I, focal signal loss; type II, multifocal signal loss without confluence; type III, confluent signal loss; and type IV, complete homogeneous reduction in marrow signal. Opposed-phase gradient-echo sequences demonstrated markedly greater red-yellow marrow contrast than conventional spin-echo sequences. Follow-up studies in three patients using a gradient-echo sequence with TE varying from 10 to 21 ms at 1-ms increments showed a cyclic increase and decrease in red and yellow marrow signal intensity depending on the TE. The contribution of intravoxel chemical shift effects on red-yellow marrow contrast in opposed-phase gradient-echo images was verified by almost complete cancellation of the TE-dependent marrow signal oscillation with use of a chemically selective pulse presaturating the water protons. Hematopoietic marrow in the adult distal femur in the absence of hematologic abnormalities is found primarily in women of menstruating age.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Vitamin D and parotid gland function in the rat.

1. We previously reported that parotid gland secretion is decreased in rats deprived of vitamin D (Glijer, Peterfy & Tenenhouse, 1985). In the present study we examine whether this effect is a direct result of the absence of vitamin D or due to the secondary systemic effects of vitamin D deficiency. 2. Offspring of rats maintained on a calcium-supplemented (1.2%), vitamin-D-deficient diet were weaned onto the same diet and examined after 8 weeks. Using this method it was possible to maintain serum calcium and parathyroid hormone concentrations within normal limits. Serum 25-hydroxyvitamin D (25(OH)D3) was not detectable, but 1,25-dihydroxyvitamin D (1,25(OH)2D3) concentrations were normal. 3. Pilocarpine-stimulated flow of parotid saliva was reduced 57% in vitamin-D-deprived animals, but amylase secretion was unchanged. Treatment with vitamin D3 returned flow rates to normal. 4. The concentration of calcium in parotid saliva was normal in vitamin-D-deprived rats, although total parotid calcium output was reduced 57%. 5. Pilocarpine-stimulated salivary flow from submandibular gland, a tissue which does not possess 1,25(OH)2D3 receptors, was normal in vitamin-D-deprived rats. 6. Heart rate and arterial blood pressure changes in response to I.V. pilocarpine administration were identical in normal and vitamin-D-deficient rats. 7. Auriculotemporal nerve-stimulated flow of parotid saliva was also reduced by 50% and administration of vitamin D3 to these rats corrected this abnormality. 8. It is concluded that fluid and electrolyte secretion from parotid gland is directly dependent on vitamin D; abnormal parotid gland function seen in vitamin-D-deficient rats is not due to secondary hypocalcaemia or hyperparathyroidism, nor can it be explained by haemodynamic changes evoked during systemic administration of pilocarpine. We further conclude that the metabolite of vitamin D responsible for this effect is not 1,25(OH)2D3.

Animals↗
PubMed1985

The effect of vitamin D deficiency on secretion of saliva by rat parotid gland in vivo.

The role of vitamin D in parotid gland function was investigated by measuring the composition and rate of production of parotid saliva in response to pilocarpine injection in vitamin-D-deficient and replete rats in vivo. Rats fed a vitamin-D-free diet from weaning (G1) were studied after 8 weeks of diet at which time they had a decreased rate of growth, were hyperparathyroid and hypocalcaemic but still had detectable serum 1,25-dihydroxycholecalciferol (1,25(OH)2D3). Rats which were the offspring of vitamin-D-deficient mothers and which were maintained on a vitamin-D-free diet from weaning (G2) had a decreased rate of growth from birth, were hypocalcaemic and hyperparathyroid and at no time had any detectable serum 1,25(OH)2D3. In response to pilocarpine, the volume of parotid saliva produced by G1 animals was no different from the controls (G1 animals receiving supplemental vitamin D) whereas that produced by G2 animals was reduced more than 65%. The total amount of amylase secreted was unchanged in either group of experimental animals so that the concentration of amylase in the parotid saliva from G2 animals was increased. The concentration of calcium in parotid saliva changed in parallel with the changes in serum calcium in G1 and G2 animals. It is concluded that the primary source of parotid saliva calcium is the extracellular fluid and not zymogen granules and the transepithelial transport of this calcium is independent of vitamin D; the secretion of electrolytes and water, which in the parotid gland require extracellular calcium, is dependent on vitamin D. It is proposed that the vitamin is necessary for the synthesis of a protein(s) which is essential for the utilization of extracellular calcium in this secretion process.

Amylases↗
PubMed1982

Vitamin D receptors in isolated rat parotid gland acinar cells.

Rat parotid gland was examined for the presence of 1 alpha, 25-dihydroxycholecalciferol receptors using sucrose density gradient ultracentrifugation techniques. [3H] DHCC bound specifically and with high affinity to a 3.2 S protein present in nuclear and cytosolic fractions of isolated parotid acinar cells. Values for the equilibrium dissociation constant and for the receptor concentration were determined to be approx. 0.1 nM, and 12 fmol/mg protein, respectively. In competitive inhibition experiments, the 3.2 S protein displayed 100-fold lower affinity for 25-hydroxycholecalciferol than for DHCC, and did not bind estradiol or methylprednisolone. These results suggest that rat parotid gland acinar cells contain classical DHCC receptors. A similar approach failed to provide evidence of DHCC receptors in isolated pancreas acinar cells, lacrimal gland or submandibular gland. It has been previously reported that vitamin D is essential for normal exocrine secretion from the rat parotid gland (Tenenhouse, A. and Afari, G. (1978) Biochim. Biophys. Acta 538, 631-634). The present findings suggest that this effect is the result of a direct action of DHCC on the parotid gland acinar cell. The absence of DHCC receptors in other exocrine cells suggests that tissue sensitivity to DHCC is not a general property of exocrine systems.

Animals↗
PubMedDate not supplied

Tarsal tunnel syndrome caused by strain of an anomalous muscle: an MRI-specific diagnosis.

Tarsal tunnel syndrome (TTS) is a compression neuropathy of the posterior tibial nerve in the ankle, commonly caused by a mass lesion such as ganglion, tumor, fracture, or post-traumatic fibrosis. Although anomalous muscle is relatively common in the ankle, there has been only one report to date implicating it in TTS. This case demonstrates MR findings of a strained flexor digitorum accessorius longus muscle as an unusual cause of TTS.

Adult↗