Thomas H. Berquist

Radiologic Anatomy of the Painful Bunionette

Radiographs were studied of 91 feet in 62 patients with the diagnosis of bunionette and no prior bunionette or hallux valgus operations. Various radiologic measurements were compared to a matched control group with no bunionette symptoms or previous forefoot operations. The bunionette group had a significantly increased metatarsophalangeal 5 angle, intermetatarsal 4–5 angle, and intermetatarsal 1–2 angle compared to the control group. Bunionettes were not commonly associated with lateral bowing of the fifth metatarsal or with an increased fifth metatarsal head width. Symmetry was noted between symptomatic and opposite asymptomatic feet, with the exception of an increased intermetatarsal 4–5 angle in the symptomatic feet.

Erdheim-Chester disease: radiographic findings in five patients

Abstract We present the case histories of five patients with Erdheim-Chester disease, a rare lipoidosis that has several typical radiographic features. In all the patients, the diaphyses and metaphyses of the extremities demonstrated a symmetric pattern of diffuse or patchy increased density, a coarsened trabecular pattern, medullary sclerosis, and cortical thickening. The epiphyses were spared in four patients and partially involved in one. The axial skeleton was involved in one patient. Radiotracer 99mTc accumulated in areas of radiographic abnormalities in all patients. In one patient, MRI demonstrated an abnormal signal, corresponding to radiographic abnormalities. The signal was hypointense to muscle on T1-weighted sequences and heterogeneously hyperintense and hypointense to normal bone marrow on T2-weighted sequences. Xanthogranulomatous lesions infiltrated the retroperitoneum in one patient, the testes in one patient, the eyelids in one patient, and the orbits in two patients.

Evaluation of radiographic findings in painful hip arthroplasties

A retrospective study of 50 surgically confirmed painful hip arthroplasties was performed to identify the roentgenographic findings that are most important in the detection of component loosening or infection. Plain film radiographs and subtraction arthrograms were reviewed in all cases, and specific features revealed by these two radiographic modalities indicative of component failure were identified. Seventeen patients had radioisotope bone scans and 13 of these had additional gallium scans. Plain film roentgenograms correctly identified loosening in 69% of acetabular and 84% of femoral components. Subtraction arthrography had an accuracy of 96% for both acetabular and femoral component loosening. Scintigraphic studies were correct in 77% of acetabular and 89% of femoral components; gallium scans identified 77% of infected hip prostheses.

Utility of the plain abdominal radiograph for diagnosing ureteral calculi

Our study was designed to measure sensitivity, specificity, predictive value, and accuracy of the plain abdominal radiograph (PAR) for diagnosing ureteral calculi (UC) in our emergency department (ED), and to determine if obtaining this test in the ED provides clinically useful diagnostic information. Records of 206 adult patients (147 men, 59 women) who underwent emergency excretory urography as part of an ED evaluation for possible ureteral stones were reviewed. A retrospective scoring index was devised to estimate the clinical probability of a ureteral stone for each patient. All patients had a PAR shortly before the excretory urogram (EXU) was performed. Each PAR was separated from the corresponding EXU, and both were independently reviewed for radiographic evidence of ureterolithiasis. The results of the PAR and EXU interpretations were compared. There were 92 true-positive PARs (45%), 19 false positives (9%), and 39 true negatives (19%), yielding a sensitivity of 62% and a specificity of 67%. In patients with a high estimated clinical probability of a ureteral calculus, the PAR had a positive predictive value of 86% and a negative predictive value of 22%. In the remaining patients, the positive and negative predictive values of the PAR were 69% and 72%, respectively. Each patients clinical index score was compared to his or her EXU results. For detecting UC, the sensitivity of our scoring index was 82%, and the specificity was 51%; the positive predictive value of the scoring index was 82%, and the negative predictive value was 52%.(ABSTRACT TRUNCATED AT 250 WORDS)

Magnetic resonance imaging: application in musculoskeletal infection

Forty-two patients with clinically suspected osteomyelitis were examined using magnetic resonance imaging (MRI). Twenty-seven patients (64%) had previous surgery or fracture, and 15 (36%) were referred for differentiation of acute osteomyelitis from bone tumors or other pathologic conditions. MRI was compared with computed tomography in 12 cases and with 111In-labeled leukocytes scans in 22. With MRI, 92% of proved infections were detected, and bone and soft-tissue changes were more evident than with routine radiographs, tomography, or computed tomography. In patients with negative cultures and no previous surgery or fracture, it was difficult for MRI to differentiate operative changes from infection. In these patients, 111In-labeled leukocyte images were more specific than MRI.

Imaging-Assisted Percutaneous Biopsy of the Thoracic Spine

Confirmation of tissue pathologic changes often is necessary before appropriate therapy can be instituted for lesions of the thoracic spine. Plain film roentgenography and computed tomography provide the key information needed for the percutaneous biopsy procedure. The location and type of bone involvement (lytic or sclerotic) and the presence or absence of a soft tissue mass determine the imaging technique and the choice of needle to use for safe and accurate performance of the procedure. In 26 patients with thoracic spinal or paraspinal lesions (or both), biopsy was done with use of fluoroscopic or computed tomographic guidance. The overall accuracy was 90%. Pneumothorax occurred in two patients. Percutaneous biopsy is a rapid, safe technique for diagnosis of lesions of the thoracic spine.

Magnetic resonance imaging of soft-tissue tumors: Comparison with computed tomography☆

Twenty-seven patients with soft-tissue tumors were examined with a Picker 0.15-tesla resistive magnet and by computed tomography (CT). In all but one patient, MRI was better than or equal to CT in defining the anatomic extent of the tumor. We could determine whether major vascular structures were engulfed by the tumor in 80% of the MRI examinations but only in 62% of the CT scans. MRI and CT were equally effective in determining the presence or absence of bony invasion. The MRI images of all the tumors showed increased signal intensity relative to normal muscle when spin-echo (SE) pulse sequences with long repeat times were used (SE: echo time [TE], 60 ms; repetition time [TR], 2,000 ms). When T1 weighted pulse sequences were used (SE: TE, 30 ms; TR, 500 ms or inversion recovery: inversion time, 500 ms; TE, 40 ms; TR, 2,000 ms) the malignant tumors showed decreased signal intensity compared to normal muscle. Only lipomas showed high signal intensity on both T1 and T2 weighted pulse sequences.

Benign and Malignant Soft-Tissue Tumors: Posttreatment MR Imaging

Soft-tissue sarcoma requires aggressive treatment, often with a combination of radiation therapy, chemotherapy, and surgical resection. Even after multimodality treatment, local recurrence is common, and regular follow-up imaging at short intervals is required. Interpretation of posttreatment magnetic resonance (MR) images may be complicated by changes in the surgical bed or treatment field. The challenge of distinguishing posttreatment change from recurrent tumor may be minimized by using an organized, systematic approach to imaging, with emphasis on the patients clinical and surgical history and a review of pretreatment images. Common changes that result from radiation therapy include soft-tissue trabeculation, increased fatty marrow, and focal marrow abnormalities. Rarely, radiation-induced malignancies may develop within the treatment field. Chemotherapy also influences posttreatment imaging appearance. Occasionally, it causes a substantial increase in tumor size that is a result of chemotherapy-induced hemorrhage. Although myocutaneous flaps used in reconstructive surgery may mimic a mass, they demonstrate time-dependent changes in size, signal intensity, and enhancement on MR images. Recurrent tumor is characterized by the presence of a discrete nodule or mass with signal characteristics that typically mirror those of the original tumor. MR imaging sequences such as unenhanced T1-weighted fat-suppressed and gradient-echo sequences may help differentiate posttreatment hemorrhage from local tumor recurrence. A consistent imaging approach combined with a detailed knowledge of the patients history, familiarity with pretreatment images, and an understanding of the various posttreatment changes enables optimal monitoring of the treatment bed and maximizes accuracy in the detection of recurrence.

Imaging appearance of diffuse neurofibroma.

OBJECTIVE The purposes of this study were to describe the imaging appearance of diffuse neurofibroma in 10 patients and to summarize demographic data on a large group of patients. MATERIALS AND METHODS Retrospective review of the pathology and radiology teaching databases at two institutions yielded the cases of 339 patients with a pathologic diagnosis of diffuse neurofibroma. Diagnostic-quality images were available for 10 patients. Images from MRI (n = 8), CT (n = 5), and sonographic (n = 1) examinations were evaluated for lesion location, size, depth of involvement, growth pattern, and intrinsic signal intensity, attenuation, or echogenicity. Demographic information, associated lesions, and tumor location were recorded for all patients. RESULTS Among 10 patients with images, eight of whom had neurofibromatosis, diffuse neurofibroma involved the skin and subcutaneous tissues (n = 9) and frequently extended to the fascia over muscle (n = 6). Plaquelike (n = 5) and infiltrative (n = 3) growth patterns were most common. One lesion had a mixed growth pattern. Prominent internal vascularity was common (n = 5). MRI signal intensity and CT attenuation were typically nonspecific. Enhancement was intense in all five patients with contrast-enhanced MR examinations. Including patients with and those without images, 349 diffuse neurofibromas were present in 339 patients. The mean patient age was 35.1 years. Lesions involved the extremities (n = 120), trunk (n = 122), head and neck (n = 98), and deep structures (n = 9). CONCLUSION Diffuse neurofibroma frequently grows as a plaquelike or infiltrative lesion involving the skin and subcutaneous tissues. Prominent internal vascularity is common. There is a much wider soft-tissue and age distribution and association with neurofibromatosis than previously reported.

Postoperative Evaluation of the Total Ankle Arthroplasty

OBJECTIVE The purpose of this article is to review the basic design features of second-generation total ankle arthroplasty components and to illustrate the normal and abnormal postoperative imaging features associated with such devices. The usefulness of CT in postoperative evaluation will be highlighted. CONCLUSION Postoperative evaluation of the total ankle arthroplasty necessitates a familiarity with the various designs currently in use. Radiography serves as an integral component in the postoperative evaluation of such devices, with CT offering further characterization of radiographic abnormalities.