Comparative analyses of multi-species sequences from targeted genomic regions.

The systematic comparison of genomic sequences from different organisms represents a central focus of contemporary genome analysis. Comparative analyses of vertebrate sequences can identify coding and conserved non-coding regions, including regulatory elements, and provide insight into the forces that have rendered modern-day genomes. As a complement to whole-genome sequencing efforts, we are sequencing and comparing targeted genomic regions in multiple, evolutionarily diverse vertebrates. Here we report the generation and analysis of over 12 megabases (Mb) of sequence from 12 species, all derived from the genomic region orthologous to a segment of about 1.8 Mb on human chromosome 7 containing ten genes, including the gene mutated in cystic fibrosis. These sequences show conservation reflecting both functional constraints and the neutral mutational events that shaped this genomic region. In particular, we identify substantial numbers of conserved non-coding segments beyond those previously identified experimentally, most of which are not detectable by pair-wise sequence comparisons alone. Analysis of transposable element insertions highlights the variation in genome dynamics among these species and confirms the placement of rodents as a sister group to the primates.

Intermetatarsal spaces: analysis with MR bursography, anatomic correlation, and histopathology in cadavers.

PURPOSE: To describe the normal magnetic resonance (MR) imaging-depicted anatomy of the intermetatarsal spaces, with emphasis on the MR imaging appearance of the intermetatarsal bursae, and to correlate the MR findings with those seen in anatomic sections and at histopathologic analysis. MATERIALS AND METHODS: Conventional radiography and pre- and postcontrast T1-weighted and fat-saturated T1-weighted spin-echo MR imaging were performed in 32 intermetatarsal spaces in eight human cadaveric feet. The cadaveric specimens were sectioned in planes corresponding to those at MR imaging for anatomic correlation. The intermetatarsal space anatomy was analyzed. Histopathologic examinations of the bursae were performed. RESULTS: The intermetatarsal spaces were located in the forefoot between two metatarsal heads, below and above the deep transverse metatarsal ligament (DTML) that separated the spaces into two levels. The superior level contained the synovial bursa, the plantar and dorsal interosseous muscles and tendons, and the collateral ligament complexes of the metatarsophalangeal joints. The inferior level contained lumbrical muscles and neurovascular bundles. The bursae extended distally to the DTML in the second and third spaces close to the neurovascular bundles and did not extend beyond the DTML in the first and fourth spaces. In the first intermetatarsal space, the bursa had a specific appearance as it coursed along the adductor hallucis tendon as a tendon sheath. Histopathologic examination of the bursae revealed a single layer of attenuated cells. CONCLUSION: MR bursography provided detailed information about the intermetatarsal anatomy, especially the intermetatarsal bursae.

Elbow synovial fold syndrome: MR imaging findings.

OBJECTIVE: We describe the anatomy and MR imaging appearance of elbow plicae. MATERIALS AND METHODS: First, five cadavers were evaluated by sectioning and using MR arthrography for evidence of normal or prominent synovial folds to determine the potential origin of elbow plicae. Next, 164 consecutive MR images were evaluated to determine the frequency of the plicae in a clinical population. Last, we retrospectively studied a selected group of eight patients who underwent preoperative MR imaging and in whom enlarged synovial folds were confirmed at surgery. RESULTS: In the cadavers, the synovial fold appeared to originate from the synovium adjacent to a posterior fat pad. In the clinical population, half the patients showed a synovial fold at the same location; however, most folds were less than or equal to 2 mm in thickness. The eight patients presented clinically with symptoms mimicking an intraarticular body. The synovial fold in symptomatic patients was seen posteriorly just above the olecranon and averaged 3 mm in thickness. CONCLUSION: A synovial fold extending from the posterior fat pad in the elbow is a frequent finding on MR imaging. In a subgroup of patients, plicae, when thickened, may present clinically as a locking elbow. However, overlap exists between the thicknesses of symptomatic and asymptomatic plicae.

Urothelial and prostate carcinoma metastasizing to the same lymph node: a case report and review of the literature.

We report herein a case of a collision tumor composed of high-grade urothelial carcinoma and a Gleason grade 3+4 prostate adenocarcinoma metastasizing to the same lymph node. After the patient underwent cystoprostatectomy for known urothelial carcinoma, he was incidentally discovered to have a second primary prostate tumor. Lymph node examination revealed that one node appeared to have metastatic foci from both primary tumors. The presence of 2 tumor types colliding in the same lymph node was confirmed using immunohistochemical stains, including monoclonal carcinoembryonic antigen, prostate-specific antigen, prostatic acid phosphatase, cytokeratins 7 and 20, and CD57. We also stained both primary tumors with the same panel as an internal control. Although 2 similar collision tumors have been reported in the literature in the past, neither used a battery of immunohistochemical stains to definitively distinguish one tumor from the other. Herein, we review the literature on urothelial and prostate collision tumors and some of the special stains used to distinguish them.

Pigmented villonodular synovitis of the hip presenting as a retroperitoneal mass.

We present an unusual case of diffuse pigmented villonodular synovitis (PVNS) of the hip presenting as a large retroperitoneal mass in an asymptomatic 39-year-old man. Initial imaging characteristics and findings on core needle biopsy suggested soft tissue sarcoma. However, incisional biopsy showed findings of PVNS. The patient underwent radical synovectomy and total joint replacement, with no change in the large retroperitoneal component after 15 months of follow-up.

Intramedullary osteosclerosis: imaging features in nine patients.

PURPOSE: To determine the conventional radiographic, computed tomographic (CT), magnetic resonance (MR) imaging, scintigraphic, and histologic features of intramedullary osteosclerosis and to review the clinical features. MATERIALS AND METHODS: Nine female patients with leg pain and imaging features indicative of intramedullary sclerosis were seen during a 25-year period. None of the patients had a history of trauma or infection, familial bone disease, or related abnormal laboratory findings. Imaging studies included radiography (n = 9), CT (n = 4), MR imaging (n = 5), and skeletal scintigraphy (n = 5). Histologic correlation was available in five patients. RESULTS: Sixteen bone lesions (midtibia, n = 14; distal fibula, n = 1; and proximal femur, n = 1) were evident. Both lower extremities were involved in seven patients, and a single extremity was involved in two. Intramedullary sclerosis was present, as was cortical thickening, mainly in the diaphysis of the long bones, without extensive periosteal reaction or soft-tissue involvement. Findings at bone scintigraphy were positive in all lesions. Histologic analysis showed nonspecific changes of markedly sclerotic bone with a variable degree of mineralization and maturity. CONCLUSION: Intramedullary osteosclerosis is a distinct disorder that typically affects the diaphysis of one or both tibiae in women. Characteristic imaging findings, when coupled with clinical information, allow precise diagnosis.

Tarsal sinus: arthrographic, MR imaging, MR arthrographic, and pathologic findings in cadavers and retrospective study data in patients with sinus tarsi syndrome.

PURPOSE: To evaluate the tarsal sinus by using different imaging techniques and specialized planes. MATERIALS AND METHODS: Magnetic resonance (MR) imaging of the tarsal sinus was performed in 10 cadavers. Conventional arthrography of the anterior and posterior subtalar joints was then performed. Tarsal sinus ligaments were evaluated further on initial and reconstructed MR arthrograms along and perpendicular to their axes. Pathologic correlation was performed in five specimens suspected of having tarsal sinus lesions on the basis of initial imaging findings. In 37 patients with a clinical diagnosis of sinus tarsi syndrome, MR images of the ankle were obtained before and after intravenous gadolinium-based contrast material administration and were reviewed to verify the integrity of the tarsal sinus ligaments. RESULTS: Two complete and three partial cervical ligament (CL) tears and one complete interosseous talocalcaneal ligament (ITCL) tear were diagnosed with MR imaging. Only one complete and one partial CL tear were seen after evaluation of both initial and reconstructed MR arthrograms and confirmed with pathologic correlation. In 18 patients, the diagnosis was confirmed at MR imaging, which depicted ITCL and CL tears in 11 patients, isolated CL tears in three patients, ganglia in three patients, and pigmented villonodular synovitis in one patient. CONCLUSION: Cadaveric study results indicate that initial and reconstructed MR arthrograms along and perpendicular to the ligament axes are potentially useful for further evaluation of individual tarsal sinus structures.

Characterization of the "red zone" of knee meniscus: MR imaging and histologic correlation.

PURPOSE: To determine the extent and vascularity of knee menisci with conventional and gadolinium-enhanced magnetic resonance (MR) imaging in cadaveric specimens, with histologic findings as the reference standard, and to investigate signal intensity changes in menisci and perimeniscal soft tissues in symptomatic patients. MATERIALS AND METHODS: Radial dimensions and enhancement patterns of menisci were recorded and compared in (a) 12 cadaveric menisci examined with conventional and gadolinium-enhanced intermediate-weighted and fat-suppressed T1-weighted spin-echo MR imaging, high-spatial-resolution T1-weighted and fast low-angle shot MR imaging, and gross anatomic and histologic specimens and (b) 18 patients examined with conventional and gadolinium-enhanced fat-suppressed T1-weighted spin-echo MR imaging. RESULTS: No differences in radial measurements of the meniscus were found for different MR techniques (P =.551). Despite the presence of vessels in the peripheral 10%-15% of the menisci, no enhancement of menisci was detected in specimens or patients. Perimeniscal soft-tissue enhancement adjacent to the posterior horn was greater than that adjacent to the anterior horn (P <.05), and enhancement of the lateral meniscal body was greater than that of the medial meniscal body (P <.05). CONCLUSION: The wedge-shaped low-signal-intensity structure seen on MR images represents the entire meniscus. Intravenous injection of contrast material does not appear to be useful for differentiation of the vascularized from the nonvascularized zone of the meniscus.

Calcium pyrophosphate dihydrate crystal deposition in and around the atlantoaxial joint: association with type 2 odontoid fractures in nine patients.

PURPOSE: To investigate the histopathologic anatomy of calcium pyrophosphate dihydrate (CPPD) crystal deposition in and around the atlantoaxial joint and the association between CPPD crystal deposition and subchondral cysts, erosions, and fracture involving the odontoid process of the axis. MATERIALS AND METHODS: One adult cadaver demonstrating calcification in the retro-odontoid area at computed tomography (CT) was selected for further radiography, CT, and magnetic resonance (MR) imaging at the C1-2 level. Anatomic sectioning and histologic evaluations were performed in the specimen. For clinical study, radiographs (n = 5), CT scans (n = 8), and MR images (n = 6) in nine patients (mean age, 74.4 years) with odontoid process fractures and CPPD crystal deposits in and around the atlantoaxial joint were reviewed. RESULTS: In the cadaveric specimen, radiography and CT demonstrated calcifications in the transverse ligament; histologic evaluation confirmed that these calcifications were CPPD crystal deposits. In all nine patients, radiography (n = 5) and CT (n = 8) also showed calcification in areas adjacent to the odontoid process, which included the transverse ligament. T1- and T2-weighted MR imaging showed a retro-odontoid mass of low signal intensity that compressed the cervical cord in six patients. CT, MR imaging, or both demonstrated subchondral cysts, osseous erosions, or a type 2 odontoid fracture in all patients. CONCLUSION: CPPD crystal deposition disease involving the C1-C2 articulation can be a clinically important entity that may place affected patients at increased risk of pathologic fracture of the odontoid process.

Delayed diagnosis of primary non-Hodgkin's lymphoma of the sacrum.

Primary non-Hodgkin's lymphoma of bone is a rare, malignant hematologic tumor affecting most commonly persons in the fourth decade of life. The tumor produces predominantly osteolytic lesions usually in the femur and pelvic bones and, very rarely, may present with spinal epidural involvement. The authors discuss an interesting case of primary non-Hodgkin's lymphoma of bone involving the sacrum with epidural invasion, in which the atypical imaging findings along with negative biopsy results delayed diagnosis.

Calcium pyrophosphate dihydrate crystal deposition disease of the knee simulating spontaneous osteonecrosis.

A retrospective review of the frontal and lateral knee radiographs of 200 patients with calcium pyrophosphate dihydrate (CPPD) crystal deposition disease was performed. Of these 200 patients, nine patients (four male, five female, mean age 74 years, age range 63-87 years) had radiographic findings simulating osteonecrosis of the knee. One patient also had magnetic resonance imaging of the involved knee. A total of 10 knee radiographs in nine patients showed articular and periarticular calcification diagnostic of CPPD crystal deposition of the knee. In addition, all 10 radiographs showed flattening of one femoral condyle. Four of the 10 cases demonstrated an area of radiolucency in the subchondral bone surrounded by a halo of sclerosis. Eight of the 10 cases had narrowing of the involved joint compartment and osteophytosis. These findings mimic the radiographic signs of spontaneous osteonecrosis of the knee. In conclusion, flattening of the femoral condyles in CPPD crystal deposition disease simulates that of spontaneous osteonecrosis and probably relates to articular cartilage and meniscal damage that subsequently leads to stress fracture of subchondral bone with bone collapse.

Transverse ligament and its effect on meniscal motion. Correlation of kinematic MR imaging and anatomic sections.

RATIONALE AND OBJECTIVES: To evaluate the effect of the transverse ligament on translation of the menisci. METHODS: Six cadaveric knees were examined by MR imaging inside a positioning device before and after transecting the transverse ligament. The knees were examined at various positions: extension, 30 degrees of flexion, 60 degrees of flexion, and full flexion. Sagittal T1-weighted spin-echo images were generated at each knee position and evaluated for statistical differences with regard to anterior-posterior meniscal excursion. RESULTS: Statistically significant differences in meniscal excursion were found before and after transsecting the transverse ligament for anterior-posterior meniscal motion of the anterior horn of the medial meniscus at 30 degrees of knee flexion. No such significant differences were found, however, at 60 degrees of flexion and full flexion in anterior-posterior meniscal excursion of the anterior or posterior horn of either meniscus before and after transsecting the transverse ligament. CONCLUSIONS: The transverse ligament has a restricting effect on anterior-posterior excursion of the anterior horn of the medial meniscus at lower degrees of knee flexion.

Iliotibial band friction syndrome: MR imaging findings in 16 patients and MR arthrographic study of six cadaveric knees.

PURPOSE: To define magnetic resonance (MR) imaging findings in patients with the iliotibial band friction syndrome (ITBFS) and to correlate these findings with anatomic features defined at magnetic resonance (MR) arthrography in cadavers. MATERIALS AND METHODS: The anatomic relationship of the iliotibial tract (ITT) to the lateral recesses of the knee joint and the lateral femoral epicondyle was investigated with MR arthrography at full extension and at 30 degrees and 60 degrees of knee flexion in six cadaveric knees. Seventeen MR imaging studies in 16 patients with ITBFS were evaluated. RESULTS: In the cadaveric study, no interference of the lateral synovial recess with the lateral femoral epicondyle at full extension and at 30 degrees and 60 degrees of knee flexion was observed. In all specimens, correlation of MR images with macroscopic and microscopic sections revealed no primary bursa between the lateral femoral epicondyle and the ITT. In clinical studies, MR imaging findings of poorly defined signal intensity abnormalities or circumscribed fluid collections were located in a compartmentlike space confined laterally by the ITT and medially by the meniscocapsular junction, the lateral collateral ligament, and the lateral femoral epicondyle. CONCLUSION: MR imaging accurately depicts the compartmentlike distribution of signal intensity abnormalities in patients with ITBFS.

Bicipitoradial bursitis: MR imaging findings in eight patients and anatomic data from contrast material opacification of bursae followed by routine radiography and MR imaging in cadavers.

PURPOSE: To use radiography and magnetic resonance (MR) imaging after contrast material opacification of the bursae in cadaveric specimens to demonstrate the anatomy of the bicipitoradial bursa and to report MR imaging findings in patients with bicipitoradial bursitis. MATERIALS AND METHODS: Bicipitoradial bursa in eight cadaveric elbows were injected with a solution containing gadodiamide, iodinated contrast agent, and gelatin. Radiographs and MR images were obtained in each specimen, with both supination and pronation of the forearm. The morphology and relationships of the bursa were studied. Anatomic sections subsequently were obtained. MR imaging studies in eight patients with bicipitoradial bursitis were also evaluated. RESULTS: The bicipitoradial bursa revealed a smooth outline and a wide base along the superficial aspect of the radius. The mean volume of contrast material that could be injected before extravasation was 4 mL. The mean size of the bursa was 1.8 x 2.5 cm. The bicipitoradial bursa enveloped the biceps tendon, with internal septation seen in two cases. Displacement of the superficial branch of the radial nerve by the bursa was found in two specimens. Communication between the bicipitoradial bursa and elbow joint was not observed. In patients, MR imaging demonstrated fluid collections in the bicipitoradial bursa in all cases, with compression of branches of the radial nerve in two cases. CONCLUSION: The anatomy of the bicipitoradial bursa is demonstrated with radiography and MR imaging of bursae. MR imaging allows accurate diagnosis of bicipitoradial bursitis and its effects on adjacent structures.

Peripheral focal low signal intensity areas in the degenerated annulus fibrosus on T2-weighted fast spin echo MR images: correlation with macroscopic and microscopic findings in elderly cadavers.

OBJECTIVE: To correlate the peripheral focal low signal intensity areas in the degenerated annulus fibrosus on T2-weighted fast spin echo MR images with the macroscopic and microscopic findings in cadavers derived from elderly subjects. DESIGN: Twenty-eight intervertebral disks (16 lumbar and 12 cervical) derived from four nonembalmed cadavers were examined with T1-weighted spin echo and proton density-weighted and T2-weighted fast spin echo MR imaging. The signal intensities of the annulus fibrosus were evaluated on sagittal MR images and correlated with the findings on corresponding sagittal anatomic sections. The MR imaging-histologic correlation was then studied. RESULTS: Peripheral focal low signal intensity areas and adjacent regions of high signal intensity were found in five lumbar intervertebral disks. Peripheral focal low signal intensity regions consisted of disorganized compact annular fibers, tiny fissures, and dense fibrosis. The high signal intensity regions, adjacent to the areas of low signal intensity, consisted of mucoid degeneration, tiny fissures, and chondroid metaplasia. CONCLUSIONS: Awareness of the histologic findings in regions that reveal peripheral focal low signal intensity with adjacent regions of high signal intensity in the degenerated annulus fibrosus on T2-weighted images may facilitate effective interpretation of clinical MR images of the spine.

Collateral ligaments of the ankle: high-resolution MR imaging with a local gradient coil and anatomic correlation in cadavers.

Findings at high-resolution magnetic resonance (MR) imaging of the lateral and medial collateral ligaments of the ankle were compared with findings in anatomic sections from cadavers. MR imaging of six cadaveric feet was performed with a newly developed local gradient coil and axial and coronal T1-weighted spin-echo sequences. Axial imaging provided optimum views of the anterior and posterior talofibular ligaments, the deep layers of the medial collateral ligament, and the tibionavicular ligament. Coronal imaging allowed complete visualization of the calcaneofibular, posterior talofibular, tibiocalcaneal, and posterior tibiotalar ligaments. In both imaging planes, differentiation of the deep and superficial layers of the medial collateral ligament was possible. Differentiation between the syndesmotic complex and the lateral collateral ligament was accomplished easily; in particular, differentiation of the posterior tibiofibular ligament from the posterior talofibular ligament was not difficult because of the differing insertions of these ligaments. The inhomogeneous appearance of the medial collateral ligament and the posterior talofibular ligament on MR images correlated with areas of fatty tissue on corresponding microscopic sections. High-resolution MR imaging with a newly developed local gradient coil allows excellent visualization of the lateral and medial collateral ligaments of the ankle.

Intracapsular origin of the long head of the biceps tendon.

A developmental anomaly of the long head of the biceps tendon was found in a cadaveric shoulder. Findings on arthroscopy, routine MR imaging, and MR arthrography were compared and correlated with results of anatomic dissection. MR arthrography appears to be a very good diagnostic imaging method for depicting this anomaly prior to arthroscopy.

Percutaneous introducibility of the expandable vascular sheath system and injury potential of balloon-assisted thrombectomy: preliminary In vivo results.

PURPOSE: To test the percutaneous introducibility of the expandable vascular sheath (EVS) system and the safety of percutaneous balloon-assisted thrombectomy. METHODS: The EVS was inserted directly (n = 9) or through a 9.5 Fr regular vascular introducer sheath (n = 9) into the femoral arteries and veins and carotid arteries in four dogs (18-21 kg). Balloon-assisted thrombectomies were simulated in iliac arteries. Histologic examinations were done at sites of funnel deployment immediately (n = 4) and 25 days (n = 8) after the intervention. RESULTS: The EVS was successfully introduced into six of nine vessels by a direct percutaneous approach. Balloon-assisted thrombectomy using the EVS device caused localized intimal denudation, disruption of the internal elastic lamina, and mild hemorrhages into the media; one arterial dissection at the site of funnel deployment was seen. All indirect insertions and funnel deployments were successful. Twenty-five days after the experiments, intimal hyperplasia was noted in all cases. CONCLUSION: Percutaneous balloon-assisted thrombectomy may cause mild vascular injuries. Direct percutaneous introduction of the EVS device cannot be recommended yet.