Osteolytic lesions and bacillary angiomatosis in HIV infection: radiologic differentiation from AIDS-related Kaposi sarcoma

Bacillary angiomatosis is a newly recognized multisystem bacterial infectious disease seen in the setting of human immunodeficiency virus (HIV) infection. The disease is marked by cutaneous vascular lesions that contain a bacterium similar to the cat scratch disease bacillus. Antibiotic therapy leads to the resolution of both cutaneous and systemic manifestations. Of 17 HIV-infected patients with cutaneous lesions of bacillary angiomatosis, six (35%) had symptomatic osteolytic bone lesions that improved following antibiotic therapy. The authors describe the appearance of the bone lesions on radiographs, computed tomographic (CT) scans, magnetic resonance (MR) images, and radionuclide studies. Osteolytic lesions are a relatively common feature of bacillary angiomatosis in patients with HIV infection. The presence of bone lesions aids in differentiation of bacillary angiomatosis from acquired immunodeficiency syndrome-related Kaposi sarcoma, which has similar cutaneous abnormalities but no associated bone lesions.     

The clinical application of bone mineral analysis

Photon absorptiometry provides an accurate measurement of bone mineral content. In acromegaly, the bone mineral content is normal, whereas the bone mineral content is reduced by acidosis. Decreased bone mineral content occurs in alcoholics due to osteomalacia and also in anticonvulsant therapy for the same reason. In hyperparathyroidism, there is decreased bone mineral content. Corticosteroids reduce bone mineral content especially in the central skeleton similar to Cushing's disease. Glutethimide causes osteomalacia with decreased bone mineral content. Long-term heparin therapy causes bone resorption. Immobilization causes decreased bone mineral content. Bedrest and space flight reduce lower limb bone mineral content with recovery on ambulation. Conversely, activity increases bone mineral content even in the elderly and bone mineral content is greater in athletes than non-athletes. Osteoporosis is a normal process occurring from age 45 years in females and 65 in males. Bone loss is related to menopause and lactation in females and may be arrested by estrogens, fluoride (with calcium and vitamin D), and possibly calcium carbonate. Decreased bone mineral content occurs at all stages of renal failure with rapid bone mineral content loss in azotemia and during dialysis and slower loss after transplant. Parathyroidectomy does not affect bone mineral content in renal osteodystrophy.The bone mineral content is normal in compact bone but decreased in trabecular bone in patients with spinal cord injury, as well as in leprosy and diabetes. In hemiplegia, there is decreased bone mineral content on the paralyzed side. In thyrotoxicosis, there is increased formation and resorption of bone.     

Perirenal Fluid in Renal Parenchymal Medical Disease (‘Floating Kidney’): Clinical Significance and Sonographic Grading

AIM: To study the clinical significance and radiologic features of perirenal fluid in patients with renal parenchymal disease. MATERIALS AND METHODS: During the previous 5 years, nine patients were found to have perirenal fluid on sonography associated with renal parenchymal medical disease. The clinical, radiological, histopathological and laboratory data were analysed. RESULTS: The perirenal fluid is a spontaneous subcapsular transudate in patients suffering from a nephropathy with a sodium retention state, with or without renal failure. Three sonographic patterns of perirenal fluid were observed: grade 1 is a thin layer of perirenal fluid; grade 2 is a moderate amount of perirenal fluid collection with indentations of the renal parenchyma and strands in the fluid, grade 3 is a large fluid collection surrounding the kidney. CONCLUSION: The perirenal fluid represents a sign of sodium retention state and oedema in patients with intrinsic renal parenchymal medical disease which may be caused by several nephropathies. Haddad, M. C.et al. (2001). Clinical Radiology56, 979–983.     

Multiple renal aspergillus abscesses in an AIDS patient: contrast-enhanced helical CT and MRI findings

Renal insufficiency or allergic reactions for X-ray contrast agents are frequent limitations in immunocompromised hosts such as neutropenic or AIDS patients. Due to a better tolerance of contrast agents in MRI, this technique is well suited for investigation of parenchymal organs. We demonstrate an allergic AIDS patient who presented with fever and flank pain. At sonography, anechoic renal lesions were supposed to be non-complicated cysts; however, on T2-weighted MRI, the center was of high signal. Dynamic contrast-enhanced MRI of the kidneys demonstrated an enhancing rim with ill-defined margins. The lesions were supposed to be multiple bilateral abscesses. Due to the multiple dynamic contrast series, a delayed enhancement of renal parenchyma was detectable adjacent to the lesion. This was suggested as accompanying local pyelonephritis and an infectious etiology became more reliable. Aspergillus fumigatus was identified by CT-guided biopsy as the underlying microorganism. The MR appearance of this manifestation has not been described previously. Received: 8 June 1998; Revision received: 7 August 1998; Accepted: 26 August 1998     

Mycotic osteomyelitis due to<Emphasis Type="Italic"> Scedosporium Apiospermum:</Emphasis> MR imaging-pathologic correlation

Mycotic osteomyelitis is rare and occurs in immunocompromised patients after inoculation of the pathogen at a penetrating trauma site. Mycotic osteomyelitis due to Scedosporium Apiospermum is extremely rare, with only 13 cases of septic arthritis reported previously. Ours is only the third case of S. apiospermum osteomyelitis in an immunocompromised patient and the only patient with a histopathologic diagnosis from an amputation specimen. Recognition of this pathogen may be delayed due to insidious onset and negative joint fluid cultures, often requiring synovial or bone biopsies to establish the diagnosis. Delay in appropriate treatment may result in disseminating infection or even death.     

Musculoskeletal disorders associated with HIV infection and AIDS. Part I: Infectious musculoskeletal conditions

The musculoskeletal system can be affected by a variety of abnormalities in association with human immunodeficiency virus (HIV) infection. Although not as common as complications involving other organ systems, such as the pulmonary and the central nervous systems, HIV-associated musculoskeletal disorders are sometimes the initial presentation of the viral illness. Knowledge of the existence and the characteristic appearance of the conditions affecting bone, joint, and muscle in HIV-infected patients is valuable to radiologists for diagnosis and to clinicians for detection and appropriate treatment. We reviewed recent literature to provide a comprehensive assessment of the HIV-associated musculoskeletal disorders, and present radiologic examples from our own collection. This article is divided into two parts. In the first part we review the infectious musculoskeletal disorders associated with HIV illness and AIDS, including cellulitis, abscesses, pyomyositis, septic bursitis, septic arthritis, osteomyelitis, and bacillary angiomatosis. We also present a comprehensive spectrum of mycobacterial infections, consisting of tuberculous spondylitis and spondylodiskitis, arthritis, osteomyelitis, and tenosynovitis, as well as infections caused by atypical mycobacteria. Part II of this review will concentrate on non-infectious musculoskeletal conditions, including rheumatic disorders and neoplasms.     

Continuing loss of vertebral mineral density in renal transplant recipients

This cross-sectional study examined bone abnormalities by digital radiography, bone densitometry and biochemical tests in 44 clinically asymptomatic renal transplant recipients 6–195 months after renal transplantation. Abnormal radiographs were obtained in 40 of the 44 patients. Dual-energy X-ray absorptiometry (DXA) performed at the lumbar spine (L2–L4)/showed a negative Z score in all patients, ranging from –1 to –1.9 in 28 patients and less than –2.0 in 16 patients. The severity of osteopenia increased with the length of time after transplantation and there was a significant correlation with parathyroid hormone values in patients with normal and low glomerular filtration rates. Our data suggest that decreased bone density values (Z score less than –2) are present in about one-third of patients with renal transplants. Bone loss appears to continue after transplantation. Steroid therapy and immunotherapy are probably the cause of this bone loss. Bone mineral measurements alone are helpful in identifying asymptomatic patients with low bone mass after transplantation. Correspondence to: B. Bagni     

Assessment of the metabolic activity of bone grafts with <Superscript>18</Superscript>F-fluoride PET

Purpose The aims of this prospective study were to evaluate quantitative approaches to ¹⁸F-fluoride positron emission tomography (PET) imaging in allogenic bone grafts of the limbs, and to assess the time course of graft healing after surgery.Methods We performed a total of 52 dynamic ¹⁸F-fluoride PET studies in 34 patients with cancellous and full bone grafts. Seven patients were imaged three times at 6, 12, and 24 months after surgery, and four patients were imaged twice. PET data were quantitatively analyzed using non-linear regression (NLR) analysis, Patlak analysis, and standardized uptake value (SUV).Results Fluoride bone metabolism in cancellous grafts decreased by 25% from 6 to 12 months post surgery, and revealed a total decrease of 60–65% after 2 years for SUV, K_Pat, and K_NLR. Full bone grafts first showed an increase by 20% from 6 to 12 months and from then on decreased to 70% of the initial activity at the end of 2 years with either quantification method. In two patients with non-union of their full bone grafts, increases in SUV, K_Pat, K_NLR, and K₁ far above average and outside the normal time pattern were observed. Highly significant correlations were found between SUV, K_Pat, K_NLR, and K₁ for both grafts and normal limb bones. In patients imaged repeatedly, the percentage changes in fluoride graft metabolism were also significantly correlated between SUV, K_Pat, and K_NLR.Conclusion Quantitative ¹⁸F-fluoride PET is a promising tool for assessment of fluoride metabolism and normal healing in bone grafts of the limbs.     

Magnetic resonance imaging of bone marrow changes in Gaucher disease during enzyme replacement therapy: first German long-term results

Objective: . Since 1991, enzyme replacement therapy (ERT) has been available for patients with Gaucher disease in Germany. The aim of this study was to analyse the MR pattern of bone marrow involvement and response to ERT in Gaucher disease type I. Patients and design: . Thirty patients with Gaucher disease type I had MRI examinations prior to initiation of ERT with alglucerase/imiglucerase and during follow-up. Median MR follow-up and duration of ERT were 36 months. Coronal T1- and T2-weighted spin-echo images of the lower extremities were obtained to evaluate changes in the appearance of yellow marrow. MR images were categorized as having either a homogeneous (type A) or non-homogeneous patchy (type B) appearance of bone involvement and response to ERT was assessed by two radiologists. Results: . Overall, 19 of 30 patients (63%) showed an increased signal intensity on T1- and T2-weighted images after 36 months of ERT, consistent with partial reconversion of fatty marrow during treatment. Focal bone lesions surrounded by a low signal intensity (SI) rim did not respond to ERT, suggesting bone infarcts. Of the 11 patients with bone infarcts (low SI rim lesion), 82% had the non-homogeneous type B pattern (P=0.0021). In 86% of patients with splenectomy, bone infarcts were seen (P<0.05). Conclusions: . MRI using T1- and T2-weighted spin-echo sequences is a valuable, non-invasive method for monitoring bone marrow response in patients receiving ERT. A non- homogeneous patchy signal intensity of bone marrow involvement correlates with the presence of bone infarcts (P=0.0021). Received: 27 July 2000 Revision requested: 26 October 2000 Revision received: 9 March 2001 Accepted: 12 March 2001     

A long term scintigraphic bone abnormality after trauma: A pitfall in the survey for metastatic disease

A solitary bone lesion was detected by ^99mTc bone scintigraphy during a survey for metastatic disease. A trauma in this region which had occurred 47 years previously, was mentioned by the patient on questioning. This case report emphasizes the need for a precise history of traumatic events, no matter how long has passed, before a survey for metastatic disease or when an atypical lesion is noted on the bone scan.     

Temporal progression of skeletal cystic angiomatosis

Cystic angiomatosis is a rare, benign, multifocal disorder of bone and viscera, in which angiomatous deposits of both vascular and lymphatic elements result in bone lysis and organ dysfunction. We report on a case of late-onset cystic angiomatosis in a Caucasian woman who first presented at age 35 years with a lytic expansile lesion of the proximal humerus, initially diagnosed as low-grade hemangio-endothelioma. This was treated with injection of cement and prophylactic pinning. However, the lesion continued to grow, and, 5 years later, she was discovered to have disseminated bony involvement, initially thought to represent metastatic disease. However, further investigation revealed a diagnosis of cystic angiomatosis, and the patient was treated with bisphosphonates. Follow-up over a 15-year period since her initial presentation at age 35 years has shown osteosclerotic conversion of many of the lesions, with development of numerous pathologic stress fractures that have failed to heal, despite operative intervention.     

The prevalence and diagnostic significance of fluid-fluid levels in focal lesions of bone

Objective To determine the prevalence and diagnostic significance of fluid-fluid levels (FFLs) in focal bone lesions.Design and patients Clinical and radiological details of 738 consecutive patients referred with focal lesions of bone and who had undergone MRI were reviewed. FFLs were identified in 83 (11.2%). The proportion of the lesion occupied by FFLs was estimated, based on imaging in all available planes, as <1/3, 1/3–2/3, >2/3 but not the entire lesion, and complete. The degree of FFL change in each lesion was correlated with the final diagnosis, which was either histological (n=80) or clinicoradiological (n=3). There were 31 female and 52 male patients, mean age 25.5 years (range 5–83 years).Results Histology revealed 46 benign, 32 malignant and 2 non-neoplastic lesions. A clinicoradiological diagnosis was made in the 3 lesions without histology: 2 were benign (simple bone cyst and intraosseous lipoma) and 1 malignant (a metastasis). Malignant neoplasms commonly showed FFLs which occupied <1/3 of the entire lesion (n=22/32, 68.8%), and 50% of all the lesions in this group were conventional intramedullary osteosarcomas (n=16). With increasing FFL change, malignancy became less frequent: with >2/3 (but incomplete) FFL change, 81% (n=13/16) of tumours were benign. If the entire tumour showed FFL change, the histology was benign in 100% (n=11).Conclusions The extent of FFLs within a focal bone lesion appears to be inversely related to the degree of malignancy. If at least 2/3 of the lesion shows FFL change, 89% of diagnoses are benign.     

MRI findings in renal transplant recipients with hip and knee pain

Purpose

To evaluate and demonstrate the MRI findings of renal transplant recipients with hip and knee pain and to investigate the most common etiology of pain.

Materials and methods

69 hip MRIs of 57 patients with hip pain and 30 knee MRIs of 24 patients with knee pain with no history of trauma were retrospectively evaluated by two radiologists.

Results

In the evaluation of hip MRIs, 24 patients had avascular necrosis and effusion, 2 patients had bone marrow edema consistent with early stage of avascular necrosis. 18 patients had only intraarticular effusion, 6 patients had tendinitis, 6 patients had bursitis and 1 patient had soft tissue abscess. Five patients had muscle edema and five patients had muscle atrophy as additional findings to the primary pathologies. Among patients with knee pain, nine patients had degenerative joint disease. Seven patients had chondromalacia, five had bone marrow edema, six had meniscal tear, six had ligament rupture and two had bone infarct. Three of the patients had muscle edema accompanying to other pathologies.

Conclusion

The most common etiology of hip pain in renal transplant recipients is avascular necrosis as expected, intraarticular effusion is found to be the second reason for pain. However, knee pain is explained by ligament pathology, meniscal tear, chondromalacia or degenerative joint disease rather than osteonecrosis.     

Lymphocele: the spectrum of scintigraphic findings in lymphoceles associated with renal transplant

Lymphocele is a well recognized complication of renal transplant surgery. We performed a retrospective review of 305 renal transplant patients with over 2,500 scintigraphic exams to describe the pattern of activity on technetium-99m-DTPA blood flow and dynamic imaging, and iodine-131-OIH studies. Diagnostic criteria for a lymphocele were ultrasonic evidence of a perirenal fluid collection and analysis of that fluid that demonstrated BUN, creatinine, and electrolytes similar to the patient's plasma. Scintigraphic findings were attributed to a lymphocele if abnormalities were in the same area as the ultrasound fluid collection. Scintigraphic findings attributable to lymphocele resolved in all patients following surgical drainage or peritoneal window placement. Six of the 11 documented lymphoceles demonstrated a cold defect on initial dynamic images that "filled in" to equal background activity and another exceeded background. Three cases showed a rim of increased activity surrounding the lymphocele ("rim sign").     

Considering Mycobacterium haemophilum in the differential diagnosis for lytic bone lesions in AIDS patients who present with ulcerating skin lesions

Mycobacterium haemophilum has recently been recognized as a newly emerging cause of osteomyelitis in immunocompromised patients. While still uncommon, its incidence has increased significantly with the growing AIDS epidemic. Like its relatives M. tuberculosis and M. intracellulare, this organism is acid-fast positive; yet unlike its more well-known counterparts, M. haemophilum requires iron-supplemented culture media and low incubation temperatures (30–32° C) for growth. We describe a case of M. haemophilum osteomyelities in the distal femur of a 36-year old HIV-positive male, who also presented with multiple skin ulcerations. In an AIDS patients with a lytic bone lesion and concomitant skin eruptions, the diagnosis of M. haemophilum should be entertained so that special culture media can be used and appropriate treatment administered.     

Positron emission tomographic findings in a tuberculous brain abscess

Several case reports and studies have described the positron emission tomographic (PET) findings of intracranial tuberculomas and bacterial brain abscesses. However, to our knowledge, the PET pattern of a tuberculous brain abscess has not been previously described. We report the case of a diabetic heavy drinker with a left parietal tuberculous abscess. ¹⁸F-fluoro-2-deoxyglucose (FDG)-PET scans showed intense FDG uptake at the abscess periphery, where contrast enhancement was observed on a magnetic resonance image. FDG uptake was reduced within the abscess cavity and in the adjacent cerebral cortex. The possibility of a tuberculous brain abscess should be considered when FDG accumulates at the periphery of a ring-enhancing lesion in a chronically ill or immunocompromised patient.     

Aspergillus infection of the respiratory tract after lung transplantation: chest radiographic and CT findings

The objective of our study was to assess radiographic and CT findings in lung transplant patients with evidence of Aspergillus colonization or infection of the airways and correlate the findings with clinical, laboratory, bronchoalveolar lavage, biopsy and autopsy findings. The records of 189 patients who had undergone lung transplantation were retrospectively reviewed for evidence of Aspergillus colonization or infection of the airways. Aspergillus was demonstrated by culture or microscopy of sputum or bronchoalveolar lavage fluid or histologically from lung biopsies or postmortem studies in 44 patients (23 %). Notes and radiographs were available for analysis in 30 patients. In 12 of the 30 patients (40 %) chest radiographs remained normal. In 11 of 18 patients with abnormal radiographs pulmonary abnormalities were attributed to invasive pulmonary aspergillosis (IPA) in the absence of other causes for pulmonary abnormalities (8 patients) or because of histological demonstration of IPA (3 patients). In these 11 patients initial radiographic abnormalities were focal areas of patchy consolidation (8 patients), ill-defined pulmonary nodules (2 patients) or a combination of both (1 patient). In some of the lesions cavitation was demonstrated subsequently. At CT a “halo” of decreased density was demonstrated in some of the nodules and lesion morphology and location were shown more precisely. Demonstration of Aspergillus from the respiratory tract after lung transplantation does not necessarily reflect IPA but may represent colonization of the airways or semi-invasive aspergillosis. The findings in patients with IPA did not differ from those described in the literature in other immunocompromised patients, suggesting that surgical disruption of lymphatic drainage and nervous supply or effects of preservation and transport of the transplant lung do not affect the radiographic appearances. Received 24 March 1997; Revision received 27 June 1997; Accepted 20 August 1997     

Spinal osteoblastoma: CT and MR imaging with pathological correlation

Objectives. To illustrate the CT and MRI features of spinal osteoblastomas and correlate the imaging with histological findings. Design. In a retrospective review the CT and MRI features of spinal osteoblastomas with respect to mineralisation, signal intensity (SI), adjacent reactive changes, enhancement following gadolinium-DTPA (5 cases) and adjacent soft tissue masses were compared and correlated with the histological findings including the degree of osteoid formation and matrix mineralisation, vascularity and surrounding reactive changes in bone and soft tissue. Patients. Eleven patients (7 males and 4 females; age range 8–43 years, mean age 19.5 years) with 12 osteoblastomas (1 patient suffered a recurrence) were studied. Results. All lesions showed classical features on CT with varying degrees of matrix mineralisation, whereas MRI identified mineralisation in only eight of 12 cases. MRI showed low signal intensity of the lesion on both T1- and T2-weighted sequences in several cases in the absence of heavy mineralisation. In these cases, histological examination revealed diffuse osteoid production by the tumour. All patients given gadolinium showed enhancement within the tumour on MRI. Reactive bone marrow changes were identified on MRI in 10 cases, and in five of these the changes were at multiple levels. An adjacent soft tissue mass was demonstrated in five cases, but extraosseous tumour was present histologically in only two of these. Conclusions. The MRI appearances of spinal osteoblastomas are varied and show no characteristic features. MRI may also overestimate the extent of the lesion due to extensive reactive changes and adjacent soft tissue masses. CT should continue to be the investigation of choice for the characterisation and local staging of suspected spinal osteoblastomas.     

An unusual scintigraphic pattern in sickle cell patients

We reviewed the nuclear medicine files of all patients enrolled in the sickle cell disease clinic who had had scans performed within the previous 5 years. We specifically looked for patterns of tracer uptake in these scans that would correlate with the severe anemia and consequent bone marrow hyperactivity of sickle cell patients. Thirtythree patients were included (21 men and 12 women) with a mean age of 26.8 years (range 17–48 years). The appearance of each of these patients' most recent scans was examined in the areas of the distal femurs, the proximal tibias and the distal tibias; a distinct triangular shaped pattern of increased activity was identified in these areas in a majority of patients. Thirty-three patients without sickle cell disease served as age-matched controls. This pattern was seen in 65.1% (95 out of 146 images) of the sickle cell patients' delayed images and 80.4% (82 out of 102 images) of their blood pool images. In contrast, the control patients demonstrated the triangular pattern in none of their blood pool studies (0%) and only 10.9% of their delayed bone images (P<0.001). The mean age of sickle cell patients with this pattern is 25.6 years which was significantly lower than that of those without this pattern (mean=37.5 years, P<0.05). Given the high prevalence of this unique scintigraphic pattern in a group of patients with known accelerated bone marrow function, these findings may be scintigraphic evidence of bone marrow expansion. The patient's age appears to be an important factor in visualization of this pattern.Presented in part at the annual meeting of the Association of University Radiologists, April 17–21, 1988, New Orleans, Louisiana, USA     

Preoperative embolization of bone metastases from renal cell carcinoma

The purpose of this study was to correlate the effectiveness of preoperative embolization with the blood loss and transfusion requirement during surgery for bone metastases from renal cell carcinoma. Twenty-eight preoperative embolizations in 26 patients with renal cell carcinoma metastatic to bone were retrospectively evaluated and divided into two groups: Group A included the embolizations that resulted in complete devascularization of the lesion as defined by the post-embolization arteriograms, and group B included those with an incomplete result. The two groups were compared with regard to blood loss and transfusion requirement during surgery, by unpaired two-tailed Student's t-test. Where complete embolization was effected (group A, 10 cases), there was a mean blood loss of 535 ± 390 ml. When a less than complete embolization was achieved (group B, 18 cases), the mean blood loss was 1.247 ± 1.047 ml (p = 0.049). The red blood cell transfusion in group A was 1.3 ± 1 units, whereas in group B it was 2.4 ± 1.2 (p = 0.03). Preoperative embolization of bone metastases from renal cell carcinoma with subsequent complete devascularization leads to significant reduction of blood loss during surgery. Interventional radiologists should pursue and embolize every feeder to the metastasis, because any less than complete devascularization increases the amount of blood loss and the amount of red blood cell transfusion during surgery. Received: 23 June 1998; Revised: 20 November 1998; Accepted: 24 February 1999