Occult fractures of extremities

Recent advances in cross-sectional imaging, particularly in CT and MR imaging, have given these modalities a prominent role in the diagnosis of fractures of the extremities. This article describes the clinical application and imaging features of cross-sectional imaging (CT and MR imaging) in the evaluation of patients who have occult fractures of the extremities. Although CT or MR imaging is not typically required for evaluation of acute fractures, these modalities could be helpful in the evaluation of the occult osseous injuries in which radiographic findings are equivocal or inconclusive.

Lymphoscintigraphic evidence of lymph vessel dilation in the limbs of children with Brugia malayi infection

Lymphatic filariasis (LF) is targeted for global elimination by the year 2020. It was earlier believed that LF is mostly a disease of adults. Recent studies indicate that in endemic countries filarial infection starts mostly in childhood even though the disease manifestations occur much later in life. The initial damage to the lymph vessels where the adult worms are lodged is dilation, thought to be irreversible even with treatment. Most of these studies relate to bancroftian filariasis. Studies that address this early pathology in brugian filariasis in humans are scarce. We report here for the first time, the lymphatic abnormalities seen on lymphoscintigraphy (LSG) in children with Brugia malayi filariasis. LSG was performed in 100 children aged between 3-15 years, who were enrolled in the study either because they were microfilaremic; had present or past filarial disease or were positive for antifilarial IgG4 antibodies. Inguinal and axillary lymph nodes were imaged in most children. Dilated lymph vessels were visualized in 80 children and this pathology was evenly distributed in all the three study groups. Lymph vessels dilation was seen even in three year old children. The implications of these findings for management of LF and control programmes are discussed.

Using extremity magnetic resonance imaging to assess and monitor early rheumatoid arthritis: the optimal joint combination to be scanned in clinical practice

OBJECTIVE

To identify the optimal combination for detecting erosions in early rheumatoid arthritis using extremity magnetic resonance imaging (eMRI).

METHODS

In 44 patients, eMRI of 1 hand identified 77% who were erosive, 2 hands 89%, and 2 hands and feet 91%.

RESULTS

eMRI identified 4 times as many erosions as radiography. At 6 months, eMRI of 1 hand identified an increase in erosions in 50% subjects, 2 hands in 55%, and 2 hands and feet in 55%. When only subjects with a change in erosion score above the smallest detectable difference were considered, these numbers were 30%, 25%, and 20%, respectively.

CONCLUSION

eMRI provides superior erosion identification compared to radiography. Imaging 2 hands can be used as a screening tool and 1 hand to monitor erosions over time.

Review of 88 nail gun injuries to the extremities

BACKGROUND

Nail guns have been employed since 1959 to speed construction work, but with the increased productivity came an increasing number of injuries associated with the device. The majority of reported cases occur to the extremities.

METHODS

Our study retrospectively examines 88 cases of nail gun injuries to the extremities collected from a 4-year period. Radiographs and charts were used to collect data on anatomic site, type of treatment, type and duration of antibiotic treatment, and outcomes.

RESULTS

We found that infections associated with nail gun injuries were relatively rare (n=3) and in our study were limited to those patients who presented later than the day of injury. The majority of injuries were to the hand and knee (38.6% and 28.1%, respectively). No significant vascular or neurological injuries were encountered.

CONCLUSIONS

It appears that simple emergency room removal of the nail with local debridement and a short course of antibiotics is appropriate in most cases. The exception to this is where there is intra-articular or neurovascular involvement, then operative debridement is recommended.

Differentiation between schwannomas and neurofibromas in the extremities and superficial body: the role of high-resolution and color Doppler ultrasonography

OBJECTIVE

The purpose of this study was to verify whether high-resolution and color Doppler ultrasonography could distinguish schwannomas from neurofibromas.

METHODS

Seventy-six tumors in 71 patients were included in this study. There were 46 patients (50 tumors) with schwannomas and 25 patients (26 tumors) with nondiffuse neurofibromas in the extremities or superficial parts of the body. Ultrasonographic examinations were performed in all patients. The tumor size, shape, location, internal echogenicity, posterior acoustic phenomenon (eg, shadowing or enhancement), capsule, relationship with the adjacent nerve, and presence of cystic components were documented. Color Doppler studies (75 lesions) and spectral Doppler studies (44 lesions) were performed. All data were analyzed with statistical software to check the significance.

RESULTS

Both tumors presented as well-defined hypoechoic nodules on ultrasonography. They were oval or lobulated, showed posterior acoustic enhancement, and were hypervascular on color Doppler ultrasonography. There was no significant difference with respect to ultrasonographic morphologic characteristics. The rates of centric, eccentric, and undetermined associations with nerves were 40%, 20%, and 40% in the schwannomas and 46.2%, 0%, and 53.8% in the neurofibromas, respectively, showing a significant difference (P = .032). There was no significant difference in the chance of cystic changes between the schwannomas (30%) and neurofibromas (23%).

CONCLUSIONS

No ultrasonographic finding (gray scale, color Doppler, or spectral analysis) allows differentiation between neurofibromas and schwannomas of the extremities. A nerve eccentrically entering a mass was seen only in schwannomas, and that may allow differentiation between neurofibromas and schwannomas.

Bisphosphonates reduce local recurrence in extremity giant cell tumor of bone: a case-control study

BACKGROUND

Giant cell tumor (GCT) of bone is a benign but locally aggressive tumor that is characterized by the presence of mononuclear stromal cells and multinucleated giant cells. Although topical adjuvants have been used in the past, local recurrence following intralesional excision of GCT of bone continues to remain a problem. The use of bisphosphonates as an anti-osteoclastic agent in the management of osteolytic bone metastases is well accepted. Furthermore in vitro studies have shown that bisphosphonates also induce apoptosis in GCT stromal cells. Therefore our clinical study aims to investigate whether the administration of bisphosphonate as an adjuvant can further decrease local recurrence following the surgical treatment of GCT of bone.

METHOD

A retrospective case-control study was performed between 1988 and 2004. Forty-four patients with histological diagnosed appendicular GCT were included. Intralesional curettage or wide excision of the lesions was followed with cementation or biological reconstruction. Additional intravenous and oral bisphosphonates were given peri-operatively to 24 patients who were treated between 1998 and 2004. The average follow-up of the control group was 115 months while that of the treatment group was 48 months.

RESULTS

In the bisphosphonate treated group, 1 of 24 patients (4.2%) developed local recurrence. In the control group, 6 of 20 patients (30%) developed local recurrence. The difference in the recurrence rate was statistically significant between the bisphosphonate treatment group and the control group (Log Rank test p=0.056). The effect of reduction of local recurrence was significant in patients with stage III diseases. Patients treated with bisphosphonate did not report any untoward effects.

CONCLUSION

Clinical use of bisphosphonates as an adjuvant therapy for giant cell tumor of bone demonstrated a lower local recurrence rate. The clinical response seems to be more promising in stage III diseases.

Small but powerful: the oribatid mite Archegozetes longisetosus Aoki (Acari, Oribatida) produces disproportionately high forces

We investigated the holding and pulling forces generated by claws of the microarthropod Archegozetes longisetosus (Chelicerata, Acari, Oribatida) on three substrates with different roughness (R(a)=0.05 microm, 1 microm, 30 microm). Holding forces were measured perpendicular to the substrate using a strain gage force transducer; pulling forces were measured parallel to the substrate using an analytical scale. We found a significant positive correlation of surface roughness and the forces generated. Mites produced holding forces on horizontal rough surfaces (R(a)=30 microm) of up to 1180 times their weight; on vertical rough surfaces (R(a)=30 microm) they can pull with 530 times their weight, effectively involving only two pairs of legs. The relative forces are five times higher than theoretically expected for organisms of this size (<1 mm, 100 microg) and higher than any relative forces reported for insect claws. Muscles involved in claw action produced stresses up to 1170 kN m(-2), a value that is only excelled by decapod crustacean claw closer muscles. Ours is the first study of performance by chelicerate apoteles and claws and also the first to measure forces generated by any microarthropod.

Radiographic features of the limbs of juvenile and subadult loggerhead sea turtles (Caretta caretta)

This study aimed to provide the normal radiographic anatomic appearance of the limbs of the loggerhead sea turtle, Caretta caretta. Dorsopalmar and dorsoplantar radiographs were taken of the forelimbs and hindlimbs of 15 juvenile and 15 subadult loggerhead sea turtles, 17 alive and 13 dead. For comparison, computed tomographic, gross anatomic, osteologic, and histologic studies were performed on the limbs of 5 of the sea turtles. Bones from the distal part of the fore and hind flippers were seen in detail with a mammographic film-screen combination. The pectoral and pelvic girdles, superimposed by the carapace, were better seen on standard radiographs with the use of rare-earth intensifying screens. Mammographic radiographs of the manus of 5 small juvenile turtles showed active growth zones. Visualization of bone contours in the distal part of the limbs was clearer than in mammals owing to the very few superimpositions. The presence of a substantial amount of cartilage in the epiphyses produced better visibility of limb ends. We conclude that use of a mammography film-screen combination is the best way to evaluate the bony and joint structures of the limbs of sea turtles. Radiography provides reliable images for clinical purposes. Considering the low cost and logistics of this technique, it is a practical ancillary test for marine animal rehabilitation centers to use.

Lecythophora hoffmannii isolated from a case of canine osteomyelitis in Japan

A 2-year-old spayed female mongrel dog showed claudication with abnormal ossification containing fungal cells detected by biopsy. The dog was treated with ketoconazole and itraconazole perorally for 5 months; however, the osteomyelitis became aggravated, and an amputation from the scapula was performed. The right superficial cervical lymph node became swollen 5 months after the operation. The lymph node contained PAS positive fungal elements and a portion of tissue produced mycelial fungal growth on potato dextrose agar supplemented with chloramphenicol. The culture was identified as Lecythophora hoffmannii based on morphology, physiology and 100% identity in the sequence of the D1/D2 domain of the large subunit ribosomal RNA gene of the fungal species in the GenBank database (accession number AB100627). In addition, the sequence from the present isolate was submitted as AB189164. The isolate showed resistance to antifungal agents, i.e., amphotericin B, 5-FC, fluconazole, itraconazole, miconazole and micafungin. The dog developed cachexia 2 months after the onset of lymphadenopathy, and was euthanized on the 459th day after onset of clinical symptoms. This was the first disseminated case of L. hoffmannii infection in Japan.

Examination of the three-dimensional geometry of cetacean flukes using computed tomography scans: hydrodynamic implications

The flukes of cetaceans function in the hydrodynamic generation of forces for thrust, stability, and maneuverability. The three-dimensional geometry of flukes is associated with production of lift and drag. Data on fluke geometry were collected from 19 cetacean specimens representing eight odontocete genera (Delphinus, Globicephala, Grampus, Kogia, Lagenorhynchus, Phocoena, Stenella, Tursiops). Flukes were imaged as 1 mm thickness cross-sections using X-ray computer-assisted tomography. Fluke shapes were characterized quantitatively by dimensions of the chord, maximum thickness, and position of maximum thickness from the leading edge. Sections were symmetrical about the chordline and had a rounded leading edge and highly tapered trailing edge. The thickness ratio (maximum thickness/chord) among species increased from insertion on the tailstock to a maximum at 20% of span and then decreasing steadily to the tip. Thickness ratio ranged from 0.139 to 0.232. These low values indicate reduced drag while moving at high speed. The position of maximum thickness from the leading edge remained constant over the fluke span at an average for all species of 0.285 chord. The displacement of the maximum thickness reduces the tendency of the flow to separate from the fluke surface, potentially affecting stall patterns. Similarly, the relatively large leading edge radius allows greater lift generation and delays stall. Computational analysis of fluke profiles at 50% of span showed that flukes were generally comparable or better for lift generation than engineered foils. Tursiops had the highest lift coefficients, which were superior to engineered foils by 12-19%. Variation in the structure of cetacean flukes reflects different hydrodynamic characteristics that could influence swimming performance.

Mineral metabolism, bone histomorphometry and vascular calcification in alternate night nocturnal haemodialysis

BACKGROUND

Poor control of bone mineral metabolism (BMM) is associated with renal osteodystrophy and mortality in dialysis-dependent patients. The authors explored the efficacy of alternate nightly home haemodialysis (ANHHD) in controlling BMM parameters and its effects on bone mineral density and histomorphometry.

METHODS

In this prospective observational study, 26 patients on home haemodialysis (3-5 h, 3.5-4 sessions weekly) were converted to ANHHD (6-9 h, 3.5-4 sessions weekly). Biochemical parameters of BMM at baseline, 6 and 12 months, radiological parameters at baseline and 12 months and bone histomorphometry at 12 months are described.

RESULTS

Pre-dialysis serum phosphate fell from 2.13+/-0.65 to 1.38+/-0.35 mmol/L; P<0.0001. No binders were required in 77.2% compared with 7.7% at baseline. Calcium-phosphate product fell from 5.28+/-1.64 to 3.42+/-0.88 mmol2/L2; P<0.0001 and parathyroid hormone (PTH) from 301 (110-471) to 127 (47-240) ng/L; P=0.01. Bone mineral density remained stable. Vascular and ectopic calcification improved or stabilized in 87.5%. Bone histomorphometry at 12 months showed high, normal and low bone turnover in 10, 3 and 4 patients, respectively, with 6/17 patients having abnormal mineralization.

CONCLUSION

Alternate nightly home haemodialysis effectively manages biochemical parameters of BMM. Patients with very high PTH at baseline (>1000 ng/L) did not significantly improve parathyroid hormone status. Abnormal bone turnover and mineralization were present in a significant proportion of patients at 12 months but low turnover was uncommon. Vascular calcification was stabilized or improved in the majority. ANHHD compares favourably with every night and short daily therapy in relation to BMM management and may offer lifestyle advantages for patients.

Interfractional Variations in Patient Setup and Anatomic Change Assessed by Daily Computed Tomography

PURPOSE

To analyze the interfractional variations in patient setup and anatomic changes at seven anatomic sites observed in image-guided radiotherapy.

METHODS AND MATERIALS

A total of 152 patients treated at seven anatomic sites using a Hi-Art helical tomotherapy system were analyzed. Daily tomotherapy megavoltage computed tomography images acquired before each treatment were fused to the planning kilovoltage computed tomography images to determine the daily setup errors and organ motions and deformations. The setup errors were corrected before treatment and were used, along with the organ motions, to determine the clinical target volume/planning target volume margins. The organ motions and deformations for 3 representative patient cases (pancreas, uterus, and soft-tissue sarcoma) and for 14 kidneys of 7 patients are presented.

RESULTS

Interfractional setup errors in the skull, brain, and head and neck are significantly smaller than those in the chest, abdomen, pelvis, and extremities. These site-specific relationships are statistically significant. The margins required to account for these setup errors range from 3 to 8 mm for the seven sites. The margin to account for both setup errors and organ motions for kidney is 16 mm. Substantial interfractional anatomic changes were observed. For example, the pancreas moved up to +/-20 mm and volumes of the uterus and sarcoma varied <or=30% and 100%, respectively.

CONCLUSION

The interfractional variations in patient setup and in shapes, sizes, and positions of both targets and normal structures are site specific and may be used to determine the site-specific margins. The data presented in this work dealing with seven anatomic sites may be useful in developing adaptive radiotherapy.

Literature Review and suggested protocol for managing ultrasound soft markers for Down syndrome: Thickened nuchal fold, echogenic bowel, shortened femur, shortened humerus, pyelectasis and absent or hypoplastic nasal bone

Mid-trimester soft markers have been linked with Down syndrome and other aneuploidies. There are many other prenatal screening tests available with better detection rates for Down syndrome than the mid-trimester ultrasound. Many patients confronted with the diagnosis of a soft marker become anxious and may request a diagnostic test (amniocentesis) despite the associated risk of miscarriage. This is also despite the fact that most fetuses with an isolated soft marker are chromosomally normal. The management of a pregnancy with a soft marker must therefore be planned in a manner designed to minimize patient anxiety. Likelihood ratios can be used to modify a patient's 'prior risk' (based on age or prior screening tests) and create a new risk. This calculation may help identify a subset of patients suitable for further investigation. It has been proposed that 'negative' likelihood ratios can be used to reduce a patient's risk if no soft marker is found at a mid-trimester ultrasound. There remain concerns about this approach and further research is required before this approach enters common practice. The published work surrounding the management of thickened nuchal fold, echogenic bowel, shortened femur, shortened humerus, pyelectasis (renal pelvis dilatation) and hypoplastic nasal bone is reviewed. Each soft marker has different associations and individual management plans for each of these soft markers are presented. Although isolated single umbilical artery is not usually considered a soft marker of aneuploidy, a management plan for this common finding is also included.

A QTL study of growth and body shape in the inter-species hybrid of Père David's deer (Elaphurus davidianus) and red deer (Cervus elaphus)

An interspecies deer hybrid resource population developed from a cross of Père David's and red deer was used to detect QTL that account for species differences. A genome scan, coupled with composite interval mapping, was conducted to search for QTL controlling body measurements at pre-pubescent age (6 months of age) and puberty (15 months of age) in this interspecies hybrid. Five linkage groups that harbour QTL affecting morphology were identified. A joint-traits analysis was used to search for putative pleiotropic QTL on four of these linkage groups, and three were significantly associated with pleiotropic QTL for nose width and foot length (metacarpal and phalanges), which collectively accounted for 29-58% of the phenotypic difference between the two deer species. This study suggests that a few loci with large pleiotropic effects may be responsible for species-specific differences in growth and structure-related traits.

First-trimester fetal limb biometry in Chinese population

OBJECTIVES

To establish reference ranges for fetal limb biometry obtained by transabdominal ultrasound examination at 12-14 weeks of gestation in Chinese women.

METHODS

A total of 1489 normal singleton fetuses between 12(+0) and 14(+6) weeks of gestation were examined transabdominally by two experienced observers. The gestation was ascertained by measurement of fetal crown-rump length (CRL) or biparietal diameter (BPD) and head circumference (HC). The lengths of the humerus and femur were prospectively worked out.

RESULTS

Gestation-specific reference ranges for limb measurements were calculated. The femur length (FL) (mean +/- SD) was 9.15 +/- 1.44 mm at 12-12(+6) weeks, 11.45 +/- 1.35 mm at 13-13(+6) weeks, and 13.64 +/- 1.60 mm at 14-14(+6) weeks; the corresponding humerus length (HL) (mean +/- SD) was 9.63 +/- 1.44 mm, 12.01 +/- 1.41 mm, 14.29 +/- 1.48 mm, respectively.

CONCLUSIONS

There was a general increase in fetal limb biometry with gestation. Fetal limb length can be an early marker of early growth restriction as well as fetal skeletal dysplasia among women in the local population.

Emergency Pediatric Imaging: Current Status and Update

Imaging has undergone a major revolution. Many procedures performed 20 years ago are no longer performed and new ones have expanded our ability to diagnose previously hidden conditions and also our knowledge of these conditions. This communication deals both with modern imaging and how it is affecting our evaluation of certain diseases but yet underscores that plain film findings still are important and should not be cast by the wayside in favor of more modern cross sectional imaging.

Less lipoatrophy and better lipid profile with abacavir as compared to stavudine: 96-week results of a randomized study

OBJECTIVE

To assess lipoatrophy, other toxicities, and efficacy associated with abacavir as compared with stavudine in HIV-infected antiretroviral-naive patients.

METHODS

This was a prospective, randomized, open trial, stratified by viral load and CD4 cell count, conducted January 2001 to July 2004. Two hundred thirty-seven adult patients with HIV infection initiating antiretroviral therapy were assigned to receive abacavir (n = 115) or stavudine (n = 122), both combined with lamivudine and efavirenz. The primary endpoint was the proportion of patients with lipoatrophy as assessed by physician and patient observation at 96 weeks.

RESULTS

A lower proportion of patients assigned to abacavir developed clinical signs of lipoatrophy (4.8% vs. 38.3%; P < 0.001). These observations were confirmed by anthropometric data. Dual energy x-ray absorptiometry (DEXA) scans performed in 57 patients showed significantly greater total limb fat loss in the stavudine arm (-1579 vs. 913 g; P < 0.001). The lipid profile in abacavir patients presented more favorable changes in the levels of triglycerides (P = 0.03), high-density lipoprotein cholesterol (HDLc; P < 0.001), and apolipoprotein A1 (P < 0.001) as well as in the ratio between total cholesterol and HDLc (P = 0.005). Throughout the study, a higher proportion of patients in the stavudine group received lipid-lowering agents as compared to the abacavir group (17% vs. 4%; P = 0.002). Similar virologic and immunologic responses were observed.

CONCLUSIONS

Assuming the limitations inherent to clinical assessment, this study shows a notably weaker association of abacavir with lipoatrophy than stavudine. DEXA scans and anthropometric measurements supported the clinical findings. In addition, the lipid changes that occurred were more favorable in patients receiving abacavir.

Radiologic anatomy of the normal appendicular skeleton of the lion (Panthera leo). Part 2: pelvic limb

Pelvic limb specimens from 14 euthanized free-ranging lions (Panthera leo), ranging in age from 16 to 170 mo, underwent radiographic evaluation in the manner described for thoracic limbs in part I of this study. On the basis of these specimens, the femur of the lion is similar to that of domestic cats, but the cranial and caudal middiaphyseal cortices are markedly thickened. The patella has a long narrow apex and flat broad base. There is a prominent lateral Os sesamoideum m. gastrocnemii. A small medial sesamoid is occasionally present, and meniscal ossicles are usually present. The head and distal extremity of the fibula are very prominent. The tarsal joint is similar to that of domestic cats. Metatarsals II-V are up to 25 mm longer than the corresponding metacarpals. All physes close by 54 mo of age.

Radiologic anatomy of the normal appendicular skeleton of the lion (Panthera leo). Part 1: thoracic limb

Thoracic limb specimens from 12 euthanized free-ranging lions (Panthera leo, 16-170 mo old) underwent radiographic evaluation. The radiographic anatomy was described but excluded any areas of the bones with possible bone pathology. Comparisons between adult and juvenile lions were made and physes described. Differences or similarities (or both) to cheetahs (Acinonyx jubatus) and domestic cats and dogs were also noted. No dissections were made to corroborate the anatomic observations, but comparisons were made to macerated museum specimens. On the basis of evaluation, the scapula has a prominent acromion, hamate, and suprahamate processes, as well as prominent nutrient foramina. The humerus is similar to that of domestic cats. The humeral and ulnar nutrient foramina originate more medially than that in domestic cats. A supracondylar foramen may sometimes be observed radiologically, although one was present on all the macerated specimens in this study. Its radiologic visibility depends on the angle of incidence of the primary beam. The lateral "anconeal tubercle" of the olecranon (situated between the processus anconeus and tuber olecrani) is usually more prominent than the medial one and tends to be hook shaped, pointing cranially. There are no sesamoids in the region of the elbow. The first digit is large with two palmar metacarpophalangeal sesamoids and a prominent sesamoid in the tendon of the M. abductoris digiti I longus, all indications of a high degree of functionality. All physes close before 66 mo of age.

Evaluation of 99mTc-UBI 29-41 scintigraphy for specific detection of experimental Staphylococcus aureus prosthetic joint infections

PURPOSE

(99m)Tc-UBI 29-41 (UBI), an antimicrobial peptide, specifically targets bacteria. We tested the ability of UBI to discriminate between infected and uninfected prosthetic joints using a rabbit model previously validated.

METHODS

Left knee arthroplasty was performed on 20 New Zealand rabbits, then 10(7) cfu of S. aureus (n = 12) or sterile saline (n = 8) was injected into the joint. On days 9 and 20 after surgery, planar UBI scintigraphy was performed in six infected and four uninfected rabbits, 1 h and 4 h p.i. (150 MBq), on a gamma camera. Operated-to-normal knee activity ratio (ONKR) was calculated on each scintigram. Then, after sacrifice, tissue samples of both knees were counted in a gamma counter.

RESULTS

One rabbit injected with sterile saline had cutaneous infection at sacrifice and was excluded from analysis. ONKR was higher in infected than in uninfected animals 4 h p.i. 20 days after surgery: 1.75 +/- 0.48 vs 1.13 +/- 0.11, p = 0.04. From 1 h to 4 h p.i., ONKR increased in 9/12 infected and 0/7 uninfected animals. According to UBI uptake intensity and kinetics, scintigraphy was truly positive in all infected cases on day 9 and in four of six infected cases on day 20. It was truly negative in two of three sterile inflamed prosthetic knees on day 9, and in all cases on day 20. Biodistribution studies revealed increased UBI uptake in periprosthetic tissues in all animals 9 days after surgery, and only in infected animals on day 20.

CONCLUSION

In this experimental study, (99m)Tc-UBI 29-41 scintigraphy permitted the early detection of acute prosthetic joint infection, and exclusion of infection in chronic sterile prosthetic joint inflammation.

The Cause and Clinical Significance of Central Tumor Photopenia on Thallium Scintigraphy of Pediatric Osteosarcoma of the Extremity

OBJECTIVE

The objectives of our study were to determine whether central tumor photopenia on thallium-201 (201Tl) scintigraphy of primary osteosarcoma results from central tumor necrosis or dense central tumor ossification and to determine the relation of this finding to tumor response to chemotherapy and to patient survival.

MATERIALS AND METHODS

After the institutional review board approved our study and waived the need for patient or parental consent, two radiologists independently reviewed 201Tl scans, conventional radiographs, and MR images of 57 patients obtained at diagnosis of extremity primary nonmetastatic osteosarcoma to detect the presence of central tumor photopenia on 201Tl scintigraphy and estimate outer tumor ossification versus inner tumor ossification and enhancement. The dynamic enhanced MRI parameters dynamic vector magnitude (DVM) and k(ep) (measure of the exchange rate between plasma and extracellular fluid space) were compared for outer tumor versus inner tumor, and the relation among 201Tl scintigraphy, conventional radiography, MRI, and the dynamic enhanced MRI parameters was analyzed. We examined whether central tumor photopenia on 201Tl imaging was related to histologic response or to patient survival.

RESULTS

Thirty-three patients (58%) had central tumor photopenia on 201Tl imaging that was not associated with central tumor ossification (p = 0.8) or with the difference between outer tumor and inner tumor contrast enhancement (p = 0.4). Central tumor photopenia on 201Tl scintigraphy was significantly associated with an increasing difference between outer tumor DVM and inner tumor DVM (i.e., outer tumor DVM minus inner tumor DVM) (p = 0.05), an increasing difference between outer tumor k(ep) and inner tumor k(ep) (i.e., outer k(ep) minus inner k(ep)) (p = 0.01), and an increasing outer k(ep)-inner k(ep) ratio (p = 0.02). We found no relation between central tumor photopenia and histologic response (p > or = 0.2). Older patients (age, > or = 13 years) with central tumor photopenia were least likely to survive, whereas younger patients (age, < 13 years) without central tumor photopenia were most likely to survive (p = 0.07).

CONCLUSION

Central tumor photopenia on 201Tl scintigraphy of primary osteosarcoma is unlikely to reflect central ossification but may be due to central necrosis reflected by higher outer tumor DVM and k(ep) than inner tumor DVM and k(ep) and may be negatively associated with survival in older patients. Prospective studies are needed to determine the value of this information in planning treatment.

Sensitivity of autopsy and radiological examination in detecting bone fractures in an animal model: Implications for the assessment of fatal child physical abuse

Skeletal injuries are often strong indicators of child abuse and their detection is therefore crucial. The aim of this study was to compare the sensitivity of three diagnostic approaches, namely autopsy, traditional (conventional) radiology, and computed tomography on "battered" piglets, in order to verify the sensitivity of each method, with respect to the true number of bone fractures assessed once the piglet was skeletonised (osteological control). Four newborn cadaver piglets who had died from natural causes were severely beaten post-mortem in every district of the body. Traditional radiography, computed tomography (CT) and autopsy were performed. The piglet was then macerated until skeletonised and the number of all fractures present recorded (osteological control). On the cranium, traditional radiology revealed only 35% circa of actual fractures, autopsy detected only 31% (P<0.01 for both comparisons versus osteological control), whereas CT imaging detected all fractures actually present. For ribs, radiology detected only 47% of all fractures present, and autopsy 65% circa (P>0.05 for both comparisons versus osteological control), while CT scans detected 34% (P<0.01). In suspected cases of fatal child abuse, we suggest that the bones of specific districts be directly analysed either at autopsy or by collecting specific diagnostic sites, such as parts of the rib cage, and subjecting them to maceration. The removed areas could be replaced with artificial material for cosmetic purposes. The authors stress the importance of combined radiological, CT scan, autopsy and osteological survey in the detection of perimortem bone fractures.

CT Angiography of Extremity Trauma

With the advent of multi-detector computed tomography, CT angiography (CTA) has rapidly become the first line imaging modality for detecting extremity arterial injuries in blunt and penetrating trauma patients. A variety of significant injuries are detected with high sensitivity and specificity. The information provided by CTAs in this patient population is often sufficient for making therapeutic decisions, such as the need for and type of surgical or endovascular interventions. Technological advances have allowed for isotropic imaging and improved quality of multi-planar and three-dimensional reformations, which aid in diagnosis and surgical planning. The rapid acquisition speed of 64 multi-detector CT scanners has facilitated integration of CTA into routine trauma CT imaging using a single contrast bolus injection.

End-to-side anastomosis for coarctation of the aorta and type A aortic arch interruption with hypoplastic aortic arch

OBJECTIVE

We investigated the advantages of reconstructing the aortic arch in neonates and infants by end-to-side anastomosis (ESA) in aortic coarctation and type A aortic arch interruption.

SUBJECTS AND METHODS

The patients were 28 neonates and infants who underwent median full sternotomy for correction of aortic coarctation (CoA) and type A interrupted aortic arch (IAA), at our institute, from October 1997 to September 2002. The cases were divided into two groups: ESA was performed in 16 cases (group A) and extended end to end anastomosis in 12 cases (group B). All repairs were made using simple clamping of the descending aorta under cardiac arrest. We compared groups A and B with regard to duration of simple clamping, postoperative blood pressure in the upper and lower extremities, echocardiographic pressure gradient, and the presence or absence of tracheal stenosis as diagnosed by postoperative clinical symptoms and chest radiography.

RESULTS

No significant difference between the groups was found in age, gender, body weight, or the ratio of CoA to IAA. In addition, there was no difference between the two groups in the duration of simple clamping or the difference in blood pressure between the lower and upper extremities. However, the echocardiographic pressure gradient at the site of anastomosis in group A was significantly lower than that in group B. There were no cases with symptoms of bronchial stenosis in either group.

CONCLUSION

ESA is a relatively simple method for treating CoA or IAA with hypoplastic aortic arch, and was found to be effective for the elimination of residual stenosis.