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C E Spritzer

Publications and source records attributed to C E Spritzer.

At least 19 recordsLinked to original sources
PubMed2001

Assessment of instability of the long head of the biceps tendon by MRI.

OBJECTIVE: To determine whether MRI can identify instability of the long head of the biceps tendon (LBT) in the rotator interval. DESIGN AND PATIENTS: A retrospective review was carried out of 19 patients, all arthroscopically examined, nine of whom had surgically confirmed instability of the LBT. RESULTS: A LBT perched on the lesser tuberosity correctly indicated all nine cases of instability with one false positive. In six of seven cases where the LBT was oval in shape, no instability of the biceps tendon existed, whereas LBT instability was present in eight of 12 patients with a flat long head of the biceps tendon. In seven of eight acutely angled intertubercular sulci there was no instability of the LBT while eight of 11 obtusely angled sulci were associated with LBT instability. By consensus impression, instability of the LBT could be determined with 67% sensitivity, 90% specificity, 86% positive predictive value, and 75% negative predictive value. CONCLUSIONS: A flat LBT perched on the lesser tuberosity with an obtusely angled intertubercular sulcus suggests the diagnosis of instability of the LBT in the correct clinical setting.

Adult↗
PubMed2001

MR findings in athletes with pubalgia.

OBJECTIVE: To describe the MR findings in athletes with pubalgia. DESIGN AND PATIENTS: Pelvic MR images of 32 athletes (30 men, 2 women) with pubalgia were studied. T1-weighted and T2-weighted (SE and FSE) and STIR images in the axial and coronal planes were obtained on a 1.5-T system. Images were reviewed for general pelvic pathology. Special attention was given to the pubic symphysis, groin and pelvic musculature, and to the abdominal wall musculature. RESULTS: Thirty surgically confirmed cases comprise the study group. Abnormalities in the following were found: pubic symphysis (21/30), abdominal wall (27/30), groin musculature, including rectus abdominis (21/30), pectineus (6/30), and adductor muscle group (18/30). CONCLUSIONS: Pubalgia is a complex process which is frequently multifactorial. The MRI findings can alter the surgical approach.

Adolescent↗
PubMed2001

Isolated pelvic deep venous thrombosis: relative frequency as detected with MR imaging.

PURPOSE: To determine the relative frequency of deep venous thrombosis (DVT) isolated to the pelvic veins, as demonstrated with magnetic resonance (MR) imaging. MATERIALS AND METHODS: The reports of 769 MR examinations performed from June 1993 through December 1999 in patients with suspected DVT were reviewed retrospectively. MR venography was performed by using a two-dimensional gradient-recalled-echo sequence (typically repetition time, 34 msec; echo time, 13 msec; flip angle, 60 degrees ). The presence of DVT was categorized by location in the pelvis, thigh, or calf. RESULTS: DVT was identified in 167 (21.7%) of the 769 MR examinations. Thirty-four (20.4%) of the 167 studies demonstrated DVT isolated to the pelvic veins. CONCLUSION: The relative frequency of isolated pelvic DVT detected with MR venography was higher than that reported in prior studies with ultrasonography (US) or ascending venography. MR venography should be performed in patients with suspected pelvic DVT or when clinical suspicion persists despite a negative US study.

Adolescent↗
PubMed2000

MR imaging of mediastinal masses.

Although ongoing developments in MR imaging have resulted in improved image quality and decreased acquisition time, MR imaging is largely used as an adjunct to CT scanning in the evaluation of mediastinal abnormalities. In this role, MR imaging often provides additional information about the nature, location, and extent of disease. MR imaging is useful in confirming the cystic nature of mediastinal lesions that appear solid on CT and, by revealing small amounts of intralesional fat, can suggest the diagnosis of hemangioma, teratoma, or extramedullary hematopoesis. MR imaging is the preferred modality for imaging neurogenic tumors, because its multiplanar capability and high contrast resolution can best demonstrate the number and nature of the lesions (differentiating cysts from neoplasms), intraspinal extension, and craniocaudad extent. MR imaging is also especially useful for evaluating the mediastinum of patients for whom the administration of iodinated contrast material is contraindicated.

Humans↗
PubMed2000

"Slip sliding Away": patellofemoral dislocation and tracking.

This article reviews the anatomy of the medial retinacular complex and the relationship of the anatomy to patellar dislocation. Clinical and radiographic findings of patellar dislocation are discussed, and the technical considerations and clinical usefulness of patellar tracking studies are addressed.

Femur↗
PubMed1999

Pitfalls in myocardial perfusion assessment with dynamic MR imaging after administration of a contrast material bolus in dogs.

RATIONALE AND OBJECTIVES: The authors evaluated the artifacts observed on myocardial perfusion curves derived from an inversion-prepared fast gradient-echo (GRE) imaging sequence in dogs after injection of a gadolinium-based contrast agent. MATERIALS AND METHODS: Six mongrel dogs were divided into three groups. In groups 1 and 2, anesthesia was maintained with pentobarbital. Group 2 also received an intravenous injection of atropine (0.03 mg/kg). In group 3, anesthesia was maintained with isoflurane (1.0%). Imaging was performed on a 1.5-T magnetic resonance (MR) imaging unit (one section per heart beat, a 30 x 15-cm field of view, 10-mm section thickness, and 64-kHz bandwidth). Region-of-interest (ROI) markers were placed on the blood pool of the left intraventricular cavity, anterior wall of the left ventricle, and anterior to the chest wall to track respiratory motion. RESULTS: In group 1, the signal intensity (SI) periodically increased during each inspiration due to respiratory sinus arrhythmia. The relation between the SI increase and the variation of the delay between images was demonstrated in vitro and by computer simulations. No periodic increase of the SI was observed when regular cardiac rhythm was maintained by pharmacologic inhibition of the vagal-mediated chronotropic response with either the addition of atropine to pentobarbital or the use of isoflurane as the anesthetic agent. CONCLUSION: In an inversion-prepared fast GRE sequence, respiratory sinus arrhythmia can induce periodic SI increase by varying the respiratory rate interval and delay between images.

Animals↗
PubMed1998

Quantification of myocardial perfusion by MRI after coronary occlusion.

The objectives of this study were to define the relationship between the first order constant of Gd-DTPA transfer (K1) and the myocardial blood flow (MBF) at rest and to compare it with an equivalent relationship obtained for positron emission tomography (PET). In a canine model of permanent coronary occlusion (n = 4), myocardial and blood time concentration curves obtained by 13N-ammonia PET and Gd-DTPA-enhanced MRI were fitted by a one-compartment model to determine K1. A linear relationship was observed between MRI-derived K1 and MBF measured by microspheres (K1 = 0.88 x flow -0.015, R = 0.95), which compares favorably with the equivalent relationship derived from PET (K1 = 0.74 x flow +0.16, R = 0.88). The results of this preliminary study suggest that, at rest and distal to a permanently occluded coronary artery, myocardial perfusion quantification by MRI is possible and can challenge PET.

Animals↗
PubMed1998

Disseminated thrombosis in primary antiphospholipid syndrome: MR findings.

We report the MR imaging findings in a patient with primary antiphospholipid syndrome, adrenal infarction and widespread thrombosis involving abdominal, pelvic, and pulmonary vessels. This syndrome should be suspected in patients with thromboses and organ infarctions of otherwise undetermined etiology.

Adrenal Glands↗
PubMed1998

Deep venous thrombosis: gradient-recalled-echo MR imaging changes over time--experience in 10 patients.

PURPOSE: To determine the gradient-recalled-echo (GRE) magnetic resonance (MR) imaging changes caused by intraluminal thrombus of the lower extremities over time and to establish GRE MR imaging criteria to help distinguish acute from previous deep venous thrombosis. MATERIALS AND METHODS: Four women and six men, aged 38-76 years, underwent GRE MR imaging two to four time after the original diagnosis of deep venous thrombosis; eight also underwent confirmatory ultrasonography at that time. Follow-up was 3 months to 1 1/2 years. All patients were treated with anticoagulants. Evidence of thrombus, signal intensity characteristics, and MR imaging appearance were evaluated. RESULTS: Acute thrombosis was identified as an occlusion or prominent filling defect within the vessel. The luminal diameter of thrombosed veins was equal to or larger than that of a corresponding, unaffected vessel in each case. Acute thrombus signal intensity tended to be decreased initially and increase over time. Residual changes due to thrombosis included the web formation (n = 3), luminal narrowing (n = 4), and wall thickening and/or slow flow (n = 5). Vessels in three patients reverted to normal. CONCLUSION: GRE MR imaging demonstrated progressive changes of venous thrombus over time. These criteria may help distinguish acute deep venous thrombosis from the residual changes of previous thrombosis.

Adult↗
PubMed1997

MRI quantitative myocardial perfusion with compartmental analysis: a rest and stress study.

K1 (first-order transfer constant from arterial plasma to myocardium for Gd-DTPA) and Vd (distribution volume of Gd-DTPA in myocardium) were measured in vivo in a canine model (n = 5) using MRI-derived myocardial perfusion curves and a compartmental model. Perfusion curves were obtained after a bolus injection of Gd-DTPA (0.04 mM/kg) with an inversion-prepared fast gradient echo sequence. Myocardium and blood signal intensity were converted to a concentration of Gd-DTPA, according to a model appropriate for short (<1 s) interimage intervals characteristic of cardiac-triggered acquisitions. Before dipyridamole-induced stress, K1 and Vd, obtained from the fit of the MRI-derived perfusion curves, were 6.2 +/- 1.4 (mHz) and 17.5 +/- 4.2%, respectively. After dipyridamole infusion, a K1 increase of a factor of 2.82 +/- 0.72 was measured (P = 0.003). No change was observed in Vd (P = 0.98). These results suggest that the K1 increase after dipyridamole reflects a flow-related effect that can be useful to quantify the MRI-derived perfusion curves.

Animals↗
PubMed1997

Flow quantification using fast cine phase-contrast MR imaging, conventional cine phase-contrast MR imaging, and Doppler sonography: in vitro and in vivo validation.

OBJECTIVE: Our purpose was to assess the accuracy of measurements of flow velocity and volume flow rate in an in vitro phantom and in healthy human volunteers using a cardiac-gated, segmented K-space, fast cine phase-contrast (PC) MR imaging technique with view sharing (fast PC). We compared this method with conventional cine PC MR imaging and Doppler sonography. SUBJECTS AND METHODS: Pulsatile flow was generated in a flow phantom that consisted of a cylindric tube having various degrees of tapered stenosis. Phase-encoded velocity maps were obtained using cine PC and fast PC MR imaging. Doppler sonography was also performed. Measurements of aortic and pulmonary artery peak systolic and minimum diastolic velocity and volume flow rate were then compared in eight healthy volunteers using the three imaging techniques. RESULTS: We found excellent agreement between fast PC and cine PC measurements of peak systolic velocity when regions of interest were drawn to exclude vessel margins (r > .99 for phantom studies, and r = .80 for human studies). Correlation between minimum diastolic velocity measurements by MR imaging was limited by noise that resulted from high encoding velocity settings. However, such correlation improved with signal averaging. When compared with predicted values of volume flow rates, both cine PC (r > .99) and fast PC (r = .97) MR imaging were more accurate than Doppler sonography (r = .78) in vitro. Measurements of cardiac output were adversely affected by low signal to noise, especially during diastole; estimates based on systolic forward flow resulted in better agreement between the two MR imaging methods. CONCLUSION: Fast PC MR flow quantification may prove to be a useful adjunct to routine MR studies for measurements of peak flow velocity. However, estimates of volume flow rate using fast PC MR imaging are limited because of increased noise during low diastolic flow as well as edge artifacts.

Adult↗
PubMed1997

Vascular diseases and MR angiography of the liver.

Delineation of the portal vein and its major attributes is essential for assessing portal hypertension and its complications. MR imaging appears to be well-suited for such an evaluation. This article provides an overview of the MR imaging techniques used to assess the portal system as well as highlights of the more common etiologies associated with altered portal venous flow.

Budd-Chiari Syndrome↗
PubMed1996

Fast spoiled gradient-recalled MR imaging of thoracic aortic dissection: preliminary clinical experience at 1.5 T.

The purpose of this study was to evaluate fast spoiled gradient-recalled (FSPGR) magnetic resonance (MR) imaging in the diagnosis of thoracic aortic dissection (TAD). Twenty-eight patients with suspected TAD underwent MR imaging with FSPGR and either cine or cardiac-gated spin-echo MR techniques. The average scanning time for the FSPGR images was approximately 1 min. Three readers interpreted the FSPGR images for the presence or absence of TAD. An ROC analysis was done. At a specificity of 90%, the sensitivity ranged from 52% to 90% for the three readers. Pulsatility artifacts and mural thrombus were causes of false-positive and false-negative readings. The areas under the ROC curves (Az) ranged from 0.85 to 0.97 for the three readers. There was a statistically significant difference in the Az values for two of the experienced readers (p = .02). The correct type of dissection was determined in only 65% of the true-positive diagnoses. FSPGR has a very limited role in screening and for rapid evaluation of the unstable patient. The results are reader dependent and susceptible to pulsatility artifacts. Determination of the type of dissection is limited. With a suspected thoracic aortic dissection, therefore, additional imaging sequences should be obtained to maximize accuracy.

Adolescent↗
PubMed1996

Proton-decoupled phosphorus-31 magnetic resonance spectroscopy in the evaluation of native and well-functioning transplanted kidneys.

RATIONALE AND OBJECTIVES: To evaluate whether decoupling improves signal-to-noise ratio and frequency resolution of in vivo kidney spectra, and to compare native and well-functioning transplant kidneys. METHODS: Proton decoupling in conjunction with three-dimensional chemical shift imaging (3D-CSI) in phosphorus-31 magnetic resonance (MR) spectroscopy was used with a spatial resolution of 64 cm3 and 17-minute acquisition time to compare native (n = 10) and well-functioning transplant (n = 9) kidneys. RESULTS: Proton decoupling improved peak amplitudes by almost 30%, as well as chemical shift resolution of in vivo kidney spectra. No statistically significant differences in phosphometabolite ratios and renal spectra were observed between healthy volunteers and patients with nonrejecting transplants. The phosphodiester-phosphomonoester ratio was 3.02 +/- 0.88, phosphomonoester-inorganic phosphate ratio was 1.07 +/- 0.44, and inorganic phosphate-adenosine triphosphate ratio was 0.58 +/- 0.22 after correction for saturation effects. CONCLUSION: Improved spectra of native and transplant kidneys can be obtained in vivo with MR spectroscopy by using a short acquisition time.

Adenosine Triphosphate↗
PubMed1996

Preoperative MR imaging in hyperparathyroidism: results and factors affecting parathyroid detection.

OBJECTIVE: To determine the sensitivity of MR imaging for the detection of abnormal parathyroid glands in patients with biochemical evidence of hyperparathyroidism and to identify the factors affecting detection. SUBJECTS AND METHODS: Between 1985, 82 patients with biochemical proof of hyperparathyroidism were referred for MR imaging of the parathyroid glands prior to surgery. Axial T1- (600/20 [TR/TE]) and T2-weighted (2500/40, 80) spin-echo images were obtained using an anterior neck surface coil. The interpretation of the MR image was compared with the findings at surgery and also correlated with gland histology, volume, and weight. Cases in which a false-positive or false-negative diagnosis was made were reviewed to determine the factors affecting detection. RESULTS: MR imaging detected 71 of 92 (77%) surgically proven abnormal glands (sensitivity, 77%; 95% confidence interval (CI), 68-86%) and misdiagnosed five (1.6%) of 314 normal glands as abnormal. There was no difference in the detection of enlarged glands in patients presenting for the first time (n = 71) (sensitivity, 77%; 95% CI, 66-86%) compared with patients with recurrent hyperparathyroidism (n = 12) (sensitivity, 77%; 95% CI, 46-95%). There was no significant difference in the detection of adenomas (sensitivity, 77%; 95% CI, 65-86%) compared with hyperplasia (sensitivity, 71%; 95% CI, 42-92%). Of five patients with ectopic parathyroid glands (1.6%), four had had previous surgery. All five glands were successfully located (three mediastinal, two in the neck). Factors contributing to a false-negative MR imaging diagnosis included small gland size and thyroid disease. Four of five false-positive diagnoses were due to enlarged lymph nodes being mistaken for parathyroid glands. CONCLUSIONS: MR imaging is an accurate technique for investigation of hyperparathyroidism. Pitfalls include low sensitivity for the identification of small glands, misinterpretation of enlarged lymph nodes as parathyroid adenomas, and misinterpretation because of thyroid disease. MR imaging is particularly useful in the investigation of patients who remain hypercalcemic following initial surgery.

Adult↗
PubMed1996

The complementary roles of fast spin-echo MR imaging and double-phase 99m Tc-sestamibi scintigraphy for localization of hyperfunctioning parathyroid glands.

OBJECTIVE: Our purpose was to evaluate and compare prospectively fast spin-echo MR imaging and double-phase technetium-99m-sestamibi scintigraphy for preoperative localization of hyperfunctioning parathyroid glands in high-risk surgical patients. SUBJECTS AND METHODS: Twenty-five patients, including 17 with a history of neck surgery, underwent preoperative MR imaging and technetium-99m-sestamibi scintigraphy. Initial interpretation of each study was made independently by two radiologists and then done in combination. At surgery, the location, weight, and dimensions, as well as detailed histopathologic evaluations, of all excised glands were recorded. RESULTS: All but two patients became normocalcemic after surgery. MR and sestamibi imaging revealed 31 of 37 (84%) and 29 of 37 (79%) of all abnormal glands, respectively. Sensitivities of MR and sestamibi imaging were higher for adenomas (17 of 18 [94%] and 16 of 18 [89%], respectively) than for hyperplastic glands (14 of 19 [74%] and 13 of 19 [68%], respectively). The specificity of sestamibi imaging (94%) exceeded that of MR imaging (75%). All ectopic glands (n = 8) were correctly localized by both techniques. Glands with atypical MR imaging characteristics (isointense or hyperintense to normal thyroid on T1-weighted spin-echo and fast spin-echo images) were more likely to have increased fat, chronic hemorrhage, or sclerosis and fibrosis (p < .05). When MR imaging and sestamibi studies were interpreted together, their sensitivities for adenomas and for hyperplastic glands were 94% (17 of 18) and 84% (16 of 19), respectively. Overall sensitivity of MR imaging and sestamibi studies interpreted together was 89%; overall specificity was 95%. CONCLUSION: The greater specificity and anatomic coverage of sestamibi scintigraphy coupled with the greater anatomic detail provided by MR imaging and its improved sensitivity over sestamibi imaging in specific patients may justify using both techniques in high-risk surgical patients who have hyperparathyroidism, particularly patients undergoing repeat surgery.

Adenoma↗