Ticks (Acari: Ixodida) on synanthropic small and medium-sized mammals in areas of the northeastern United States infested with the Asian longhorned tick, Haemaphysalis longicornis

The northeastern United States (US) is a hotspot for tick-borne diseases. Adding to an already complex vector landscape, in 2017 large populations of the invasive Haemaphysalis longicornis, the Asian longhorned tick, were detected in New Jersey (NJ) and later found to be widespread from Connecticut to Georgia. In its native range in northeastern Asia, H. longicornis is considered an important vector of deadly pathogens to humans, companion animals, and livestock. To identify the primary hosts of H. longicornis, we surveyed synanthropic small and medium-sized mammals in three different sites in suburban New Brunswick, NJ. Specifically, we collected approximately 9,000 tick specimens belonging to nine species from 11 different species of mammals sampled between May and September 2021. We found that H. longicornis feeds more frequently on rodents than previously thought, and that this invasive tick is likely exposed to important enzootic and zoonotic pathogens. Overall, we obtained detailed information about the seasonal dynamics and feeding patterns of six tick species common in the northeastern US, Haemaphysalis longicornis, Amblyomma americanum, Dermacentor variabilis, Ixodes scapularis, Ixodes texanus and Ixodes cookei. We found that unlike I. scapularis that feeds on mammals of all sizes, H. longicornis feeds on hosts following the general pattern of A. americanum, favoring larger species such as skunks, groundhogs, and raccoons. However, our survey revealed that unlike A. americanum, H. longicornis reaches high densities on Virginia opossum. Overall, the newly invasive H. longicornis was the most numerous tick species, both on multiple host species and in the environment, raising significant questions regarding its role in the epidemiology of tick-borne pathogens, especially those affecting livestock, companion animals and wildlife. In conclusion, our findings provide valuable insights into the tick species composition on mammalian hosts in NJ and the ongoing national expansion of H. longicornis.

Dismantling the ability of CT and MRI to identify the target mismatch profile in patients with anterior circulation large vessel occlusion beyond six hours from symptom onset

PURPOSE

Patients with large vessel occlusion and target mismatch on imaging may be thrombectomy candidates in the extended time window. However, the ability of imaging modalities including non-contrast CT Alberta Stroke Program Early Computed Tomographic Scoring (CT ASPECTS), CT angiography collateral score (CTA-CS), diffusion-weighted MRI ASPECTS (DWI ASPECTS), DWI lesion volume, and DWI volume with clinical deficit (DWI + NIHSS), to identify mismatch is unknown.

METHODS

We defined target mismatch as core infarct (DWI volume) of < 70 mL, mismatch volume (tissue with TMax > 6 s) of ≥ 15 mL, and mismatch ratio of ≥ 1.8. Using experimental dismantling design, ability to identify this profile was determined for each imaging modality independently (phase 1) and then with knowledge from preceding modalities (phase 2). We used a generalized mixed model assuming binary distribution with PROC GLIMMIX/SAS for analysis.

RESULTS

We identified 32 patients with anterior circulation occlusions, presenting > 6 h from symptom onset, with National Institute of Health Stroke Scale of ≥ 6, who had CT and MR before thrombectomy. Sensitivities for identifying target mismatch increased modestly from 88% for NCCT to 91% with the addition of CTA-CS, and up to 100% for all MR-based modalities. Significant gains in specificity were observed from successive tests (29, 19, and 16% increase for DWI ASPECTS, DWI volume, and DWI + NIHSS, respectively).

CONCLUSIONS

The combination of NCCT ASPECTS and CTA-CS has high sensitivity for identifying the target mismatch in the extended time window. However, there are gains in specificity with MRI-based imaging, potentially identifying treatment candidates who may have been excluded based on CT imaging alone.

Delayed Gadolinium-Enhanced MR Imaging of Cartilage (dGEMRIC) following ACL injury

OBJECTIVE

Early detection of glycosaminoglycan (GAG) loss may provide insight into mechanisms of cartilage damage in the anterior cruciate ligament (ACL)-injured patient. We hypothesized that tibial and femoral Delayed Gadolinium-Enhanced MR Imaging of Cartilage (dGEMRIC) indices would be lower in the medial compartment of the ACL-injured knee than in the contralateral, uninjured knee, and that scan order (i.e., whether the injured or the uninjured knee was imaged first) would not affect the indices.

METHODS

15 subjects with unilateral ACL injuries received a double dose of gadolinium [Gd(DTPA)(2-)] intravenously. After 90 min, both knees were sequentially imaged. The injured knee was scanned first in the odd-numbered subjects and second in the even-numbered subjects. The dGEMRIC indices of the median slice of the medial compartment were determined using the MRIMapper software. Index comparisons were made between knee status (ACL-injured vs uninjured), scan order (ACL-injured first vs uninjured first), and cartilage location (tibia vs femur) using a mixed model.

RESULTS

There was a significant difference in the mean dGEMRIC indices of the medial compartment between injured and uninjured knees (P<0.007). On average, there was a 13% decrease in the dGEMRIC index of the injured knee compared to the uninjured knee. There were no significant effects due to test order (P=0.800) or cartilage location (P=0.439).

CONCLUSIONS

The results demonstrate lower GAG concentrations in the medial compartment of the femoral and tibial articular cartilage of the ACL-injured knee when compared to the contralateral uninjured knee. The dGEMRIC indices were not sensitive to scan order; thus, sequential imaging of both knees is possible in this patient population.

Prevalence of hydrocephalus in 157 patients with vestibular schwannoma

The purpose of this study was to determine the prevalence of hydrocephalus in patients with vestibular schwannoma. A second objective was to investigate possible etiologies for hydrocephalus in this population by attempting to correlate the incidence and severity of hydrocephalus with tumor volume and extent of fourth ventricular compression. The MRI examinations of 157 adult patients with vestibular schwannoma were retrospectively reviewed. Tumor size was quantified, and the presence of accompanying hydrocephalus was assessed, categorized as communicating type or non-communicating type and then rated as mild, moderate or severe (grades 1-3). Next, the degree of fourth ventricular distortion caused by tumor mass effect was evaluated and categorized as mild, moderate or severe (grades 1-3). Spearman's rank correlation coefficient was used to test the relationships between tumor volume and (1) the extent of fourth ventricular effacement and (2) severity of hydrocephalus. Hydrocephalus was present in 28/157 (18%) cases and was categorized as mild in 11/28 (39%), moderate in 15/28 (54%) and severe in 2/28 (7%). Communicating-type hydrocephalus was present in 17/28 (61%) and non-communicating type in 11/28 (39%). There was a positive correlation between the grade of non-communicating hydrocephalus and tumor volume (r=0.38; P<0.001) and between the severity of fourth ventricular compression and extent of hydrocephalus in this group(r=0.43; P<0.001). In patients who were classified as having communicating hydrocephalus, the correlation between tumor volume and the severity of hydrocephalus was poor (r=0.19; P=0.02) as was the correlation between the extent of fourth ventricular distortion and the severity of hydrocephalus (r=0.21; P<0.01). There is a high prevalence of hydrocephalus in patients with vestibular schwannoma. In a minority of cases non-communicating type hydrocephalus is present and the severity of hydrocephalus can be attributed to the affect of tumor volume on fourth ventricular compression. More commonly, however, communicating-type hydrocephalus exists and the correlation between the severity of fourth ventricular compression and extent of hydrocephalus is poor. Therefore, other etiologies for hydrocephalus, such as tumor protein sloughing, are likely relevant.

MRI of intracerebral hematoma: value of vasogenic edema ratio for predicting the cause

We evaluated a method for quantifying vasogenic edema (VE) on MRI to identify brain hematomas caused by neoplasms. We performed a blinded review of 68 acute and subacute hematomas caused by neoplasms (22), hypertension or presumed amyloid angiopathy (27), or vascular malformations (19). The extent of vasogenic edema was quantified on an axial T2-weighted image using the VE ratio: the maximum width of high signal surrounding a hematoma and the mean diameter of the hematoma. Hematomas caused by neoplasm were associated with more vasogenic edema (mean VE ratio 104%+/-15%; mean VE width 2.4+/-0.7 cm) than non-neoplastic hematomas (mean VE ratio 37%+/-5%; P =0.001). When the width of VE was equal to or more half the diameter the hematoma (VE ratio 50%), the positive predictive value for tumor was 66%; when it was equal to or more than the diameter, the positive predictive value was 71%. All six hematomas with VE ratios > or = 150% were caused by neoplasm.

MR imaging of pituitary adenomas after gamma knife stereotactic radiosurgery

OBJECTIVE

The purpose of this study was to evaluate the response of pituitary adenomas to radiosurgery as manifested by changes in size and appearance on serial MR imaging.

MATERIALS AND METHODS

Over a mean follow-up period of 36 months, changes in 44 pituitary adenomas were assessed on 147 enhanced MR imaging studies. Prior surgery had been performed in 36 tumors (82%).

RESULTS

At the time of radiosurgery, mean tumor volume was 5.9 +/- 0.8 cm(3) (mean diameter, 2.2 cm). The mean reduction in volume at last follow-up was 41% (+/- 5%, p < 0.001), and a decrease in tumor volume of 25-100% was observed in 34 tumors (77%). Mean reduction in tumor volume at 6 months after radiosurgery was 9% (p = 0.095); at 1 year, 24% (p < 0.001); at 2 years, 34% (p < 0.001); at 3 years, 41% (p < 0.001); and at 4 years, 50% (p = 0.008). Six months after radiosurgery a slight and transient increase in size was observed in 21% of tumors. During follow-up, neither decreased contrast enhancement nor cyst development was associated with changes in tumor volume.

CONCLUSION

Tumor control was observed for most pituitary adenomas after radiosurgery and occurred gradually over a period of several years. A small increase in tumor size might be observed in the first 6 months after radiosurgery. In most cases, reductions in tumor size were not accompanied by a change in contrast enhancement or cyst formation.

Diffusion-weighted MR imaging of rim-enhancing brain masses: is markedly decreased water diffusion specific for brain abscess?

OBJECTIVE

This retrospective study investigated the specificity of restricted water diffusion for the diagnosis of brain abscess. Two of five rim-enhancing brain masses with restricted water diffusion (apparent diffusion coefficient of 0.79 [10(-3) mm(2)/sec] or less) were brain abscesses, but diagnoses in the other cases were metastatic squamous cell carcinoma (two cases) and radiation necrosis.

CONCLUSION

Although an important diagnostic sign, restricted water diffusion is not specific for brain abscess.

Subscapularis Tendon Tear: Primary and Associated Signs on MRI

PURPOSE

The purpose of this work was to investigate signs of subscapularis tendon tear on MRI.

METHOD

Preoperative written interpretations of high field (n = 9) and low field (n = 7) MRI of 16 patients with tears confirmed at surgery or arthroscopy were reviewed, followed by retrospective review of these studies.

RESULTS

A preoperative diagnosis of subscapularis tear was made in five (31%) cases. On retrospective review, primary signs of tear were present in 15 (94%) cases and in two-thirds were limited to the cranial third of the tendon. Supraspinatus tears were present in 69% of cases. Associated findings included medial dislocation (n = 4) or subluxation (n = 3) of biceps tendon, biceps tendinopathy (n = 2), superior labral tear (n = 5), and effusions of superior subscapularis recess (n = 6), subcoracoid bursa (n = 2), or both (n = 5). One or more associated signs were present in 94% of cases.

CONCLUSION

Subscapularis tear is frequently missed on MRI. Recognizing that primary signs of tear may be limited to the cranial third of the subscapularis tendon and identifying associated signs should facilitate diagnosis.

Central nervous system and renal vasculitis associated with primary varicella infection in a child

A 7-year-old girl with primary varicella presented with encephalopathy and focal neurologic deficits 10 days after her first skin lesions appeared. She was discovered to have bilateral wedge-shaped renal infarctions, and ischemic lesions in the conus medullaris, cerebral cortex, and deep gray matter consistent with a medium and large vessel arteritis on magnetic resonance imaging. This complication has never before been reported in an immunocompetent child with primary varicella infection, and it represents a rare but serious complication of childhood chickenpox.

Persistent preceding focal neurologic deficits in children with chronic Epstein-Barr virus encephalitis

Epstein-Barr virus encephalitis is a self-limiting disease with few sequelae. Persistence of neurologic deficits prior to and after the acute illness has yet to be described in children. We describe five children with persistent cognitive and focal neurologic deficits due to chronic Epstein-Barr virus encephalitis with various T2-weighted magnetic resonance imaging abnormalities. Clinical features were a 9-year-old boy with aphasia and apraxia, an 11-year-old girl with impulsivity and inappropriate behavior, a 17-year-old boy with deterioration of cognitive skills and judgment, a 5-year-old boy with complex-partial seizures, and a 6-year-old girl with obsessive-compulsive behavior. All patients had elevated serum Epstein-Barr virus titers for acute infection, with cerebrospinal fluid polymerase chain reaction positive for Epstein-Barr virus in four patients. Three children were treated with methylprednisolone with minimal improvement without changes on magnetic resonance imaging. Epstein-Barr virus encephalitis can present with chronic and insidious neurologic symptoms and should be considered in the differential diagnosis of children with acute or chronic neurologic illness of unknown etiology.

MR imaging and MR arthrography of paraglenoid labral cysts

OBJECTIVE

We investigated the pathophysiology of paraglenoid labral cysts on the basis of MR imaging, MR arthrography, and cyst aspiration.

MATERIALS AND METHODS

From 2211 MR imaging examinations, 51 (2.3%) cysts in 46 patients were identified. MR arthrography (n = 5), cystography (n = 1), arthroscopy (n = 17), percutaneous needle aspiration (n = 4), and medical records were also reviewed (n = 46).

RESULTS

On MR imaging and arthrography, cysts were best viewed on T2-weighted images. Mean cyst diameter and volume were 2.2 cm and 2.8 cm3, respectively. Fifty-seven percent of cysts were located adjacent to the posterior labrum. On MR imaging and arthroscopy, a labral tear was identified in 27 (53%) and 15 (88%) patients, respectively. Eight cysts that caused compression neuropathy were large (mean size, 3.1 cm; p = 0.04) and located next to the posterior or inferior labrum. In four of five patients, MR arthrograms showed no intraarticular contrast material in the cyst. Cystograms showed no communication with the glenohumeral joint space, and cyst aspiration resulted in temporary symptom relief; however, cysts recurred in three of four patients.

CONCLUSION

Most paralabral cysts are associated with labral tears. Paralabral cysts may be difficult to identify on MR arthrography unless a T2-weighted sequence is performed. Direct communication between a cyst and joint space rarely occurs. A posterior or inferior cyst may cause compression neuropathy of the suprascapular or axillary nerve, respectively. Cyst aspiration may result in temporary relief of symptoms, but an untreated labral tear should be suspected if cysts recur.

High-field and low-field MR imaging of superior glenoid labral tears and associated tendon injuries

OBJECTIVE

The purpose of this study was to determine the performance characteristics of high-field and low-field MR imaging for the diagnosis of a glenoid superior labral anteroposterior (SLAP) tear.

MATERIALS AND METHODS

High-field (n = 46) or low-field (n = 21) MR imaging was performed on 41 patients with SLAP tears and 26 patients with normal superior labra. The superior labrum was classified into one of four types on the basis of patterns of intralabral signal intensity. The relative frequency of rotator cuff tears and long head of the biceps tendinopathy was also assessed.

RESULTS

For the diagnosis of SLAP tear, the sensitivity of high-field MR imaging was 90% (95% confidence interval = 74%, 98%), specificity was 63% (35%, 85%), and accuracy was 80% (66%, 91%). The sensitivity of low-field MR imaging was 64% (31%, 89%), specificity was 70% (35%, 93%), and accuracy was 67% (43%, 85%). A branched linear or stellate focus of abnormal intralabral signal intensity was associated with a SLAP tear in 86% of patients. Conversely, two other labral patterns correlated with a normal superior labrum in 71% of patients. Abnormal signal intensity in the biceps tendon was seen in 15% of patients with a SLAP tear. Full-thickness (37%) and partial-thickness (31%) rotator cuff tears were often seen.

CONCLUSION

The performance characteristics of high-field MR imaging are superior to those of low-field MR imaging for the diagnosis of a superior labral tear. Rotator cuff tears can be seen in many patients with superior labral tears, but abnormal signal intensity in the biceps tendon is uncommon.

CT of the brain: a comparison of transportable and fixed-platform scanners

OBJECTIVE

The purpose of this study was to determine whether an in-hospital transportable CT scanner can provide diagnostic brain images and to compare the quality of these images with those from a conventional fixed-platform CT scanner.

SUBJECTS AND METHODS

Twenty-seven patients with known or suspected intracranial pathology underwent imaging on a transportable scanner and a fixed-platform scanner within 1 hr of each other. Images from each CT examination were evaluated independently by two neuroradiologists who were unaware of patient history. Conspicuousness of intracranial pathology and normal anatomy were rated on a 5-point scale (1 point, optimal; 5 points, poor or not visualized). Statistical comparisons were made using nonparametric tests.

RESULTS

Seven CT scans were interpreted as showing normal findings and 20 scans revealed intracranial pathology on both CT scanners. Image quality was higher on the fixed scanner (average rating, 2.42 points; SE = .12) than on the transportable scanner (average rating, 3.10 points; SE = .12) (p = .001). Depiction of the cerebellum, midbrain, and supratentorial gray-white matter was better on the fixed scanner (p < .05). However, we found no significant differences in detection of intracranial pathology between scanners. Both radiologists found images from both scanners to be diagnostic in all 27 patients.

CONCLUSION

Images of the brain on the transportable CT scanner were less clear than those on a fixed scanner. However, images from the transportable CT scanner were diagnostic in 27 consecutive patients. The implications of this finding are important for the provision of CT services for critically ill patients who cannot be transported to the radiology department.

Spinal epidural abscess: correlation between MRI findings and outcome

Our purpose was to determine if specific MRI findings in spinal epidural abscess (SEA), at the time of diagnosis, are associated with the clinical outcome. The clinical records and MRI studies of 18 patients with SEA were reviewed and follow-up was obtained from the outpatient medical record, telephone interview, or both. The association between findings on contrast-enhanced MRI and clinical outcome (weakness, neck or back pain, and incomplete functional recovery) was evaluated. With univariate analysis, narrowing of 50% or more of the central spinal canal (P = 0.03), peripheral contrast-enhancement (P = 0.05), and abnormal spinal cord signal intensity (P = 0.05) were associated with weakness at follow-up. Persistent neck or back pain was associated with spinal canal narrowing (P = 0.02), peripheral contrast-enhancement (P = 0.02), and an abscess longer than 3 cm (P = 0.04) on MRI. Incomplete clinical recovery was associated with both abscess length (P = 0.01) and the severity of canal narrowing (P = 0.01). Abscess length, enhancement pattern, and severity of canal narrowing can be incorporated in a grading system that can be used to predict outcome.

Assessment of the value of MR imaging for examining patients with angiographically negative subarachnoid hemorrhage

OBJECTIVE

Our goal was to assess the value of MR imaging to patient care in the setting of angiographically negative subarachnoid hemorrhage and to evaluate the potential of MR imaging for revealing the mechanism for idiopathic perimesencephalic subarachnoid hemorrhage.

MATERIALS AND METHODS

We retrospectively reviewed 71 patients who presented with subarachnoid hemorrhage and in whom the results of a four-vessel cerebral arteriogram were negative, a CT scan showed no evidence of intraaxial hemorrhage, and MR imaging had been performed within 72 hr of presentation. MR imaging of the brain included sagittal spin-echo T1-weighted, turbo spin-echo proton density-weighted, T2-weighted, and axial T2-weighted gradient-echo sequences. MR imaging of the cervical spine, which was performed in 41 of the 71 patients, included sagittal spin-echo T1-weighted, turbo spin-echo proton density-weighted, T2-weighted, and axial T2-weighted gradient-echo sequences.

RESULTS

Perimesencephalic subarachnoid hemorrhage was seen on CT in 25 patients; in four of these patients (16%), MR imaging revealed acute perforator territory infarction involving the caudate, putamen, or thalamus. In 26 other patients, nonperimesencephalic subarachnoid hemorrhage was revealed on CT; in two of these patients (8%), MR imaging showed the cause of the subarachnoid hemorrhage. By contrast, 20 patients had negative findings on CT scans but xanthochromic CSF on lumbar puncture; in two of these patients (10%), MR findings were interpreted as responsible for subarachnoid hemorrhage.

CONCLUSION

MR imaging showed diagnostic value in patients with angiographically negative subarachnoid hemorrhage, revealing abnormalities in 14% of the 71 patients, and resulted in a significant change in patient treatment in 6% of the patients. MR imaging also revealed an association between perimesencephalic subarachnoid hemorrhage and infarcts involving the territory of perforating arteries at the base of the brain. This finding may provide insight into the pathogenesis of perimesencephalic subarachnoid hemorrhage.

A comparison of MRI findings in patients with acute and chronic ACL tears

This retrospective study compared the magnetic resonance imaging (MRI) findings in 87 patients with acute and chronic anterior cruciate ligament (ACL) tears. Sixty patients had acute tears and 27 had chronic tears. The appearance of the torn ligament was examined on MRI, and associated meniscal and osteochondral injuries were described. All findings were verified at arthroscopy. Acute ACL tears (MRI examination was performed within 6 weeks of injury) were typified by the presence of diffuse (58%) or focal (42%) increased signal within the ligament, whereas chronic ACL tears (MRI examination was performed more than 6 months after injury) usually appeared as either a fragmented ligament (44%) or an intact band of low signal with abnormal orientation (30%). Patients with chronic ACL tears had a higher prevalence of medial meniscal tears (78% versus 40%), articular chondromalacia, and an increased posterior cruciate bow ratio (0.47 versus 0.37) in association with chronic ACL tears. A bone bruise was seen in 68% of acute ACL tears but in no case of chronic ACL tear. On MRI, there are salient differences between acute and chronic ACL tears. Chronic ACL tears are associated with a greater prevalence of meniscal and osteochondral injuries. These findings may have implications for future treatment recommendations.

A SPECT imaging study of MRI white matter hyperintensity in patients with degenerative dementia

We investigated the correlation between cortical perfusion and white matter hyperintensities on magnetic resonance images (MRI) of patients with dementia. The study included 40 subjects, each of whom had undergone both MRI and single-photon emission computed tomography (SPECT) studies as part of their diagnostic evaluation for degenerative dementia. Two neuroradiologists rated the MRI films for severity of periventricular white matter changes on a 0-5 point scale and severity of subcortical white matter changes on a 0-4 point scale. Twelve regions of interest from association cortex were sampled for the semiquantitative analysis of SPECT images. No relationship was found between these global MRI ratings and semiquantitative or qualitative SPECT findings. Dementia severity as measured by the Mini-Mental State Examination and the Clinical Dementia Rating was significantly correlated with SPECT, whereas age was significantly correlated with MRI ratings, particularly in the periventricular regions. These data support the view that cortical SPECT abnormalities are not associated with global MRI abnormalities in the subcortical and periventricular regions of patients with a clinical picture of degenerative dementia.

Contemporary imaging of athletic injuries

The team physician is faced with an array of imaging studies to evaluate the injured athlete, including CT scans, conventional and cross-sectional arthrography, bone scanning, sonography, and MR imaging. An understanding of the clinical usefulness of these examinations requires some knowledge of the physical principles on which they are based. This article presents the fundamental physical principles and summarizes the indications for these tests to the evaluation of common athletic injuries.

Cavernous hemangioma of the liver: pathologic correlation with high-field MR imaging

OBJECTIVE

MR imaging is used to characterize cavernous hemangiomas of the liver because these neoplasms have a long transverse relaxation time compared with normal liver parenchyma and other hepatic neoplasms. The purpose of this study was to correlate the pathologic findings of hemangiomas with their appearance on high-field MR images and with mean T2 relaxation time.

MATERIALS AND METHODS

Tissue cores were obtained by percutaneous needle biopsy of 14 cavernous hemangiomas, ranging in size from 1.0 to 10.9 cm. Mean relaxation time was determined from T2-weighted spin-echo MR images. Pathologic analysis included quantification of endothelial cells, identified by counterstaining to anti-factor VIII antibody.

RESULTS

We found an inverse relationship between the number of endothelial cells in the histologic specimen and the mean T2 value of the tumor (r = -.75; p < .002). Pathologic examination of tissue from three tumors with the shortest T2 relaxation times showed relatively greater amounts of connective tissue and more numerous but small and compressed vascular channels. Although the two hemangiomas less than 2 cm in diameter had T2 times less than 80 msec, no significant relationship between tumor size and relaxation time was found.

CONCLUSION

We conclude that T2 relaxation time of cavernous hemangioma is directly related to the collective size of its constituent vascular spaces. We found no statistically significant difference in measured T2 relaxation time and no difference in histologic appearance between hemangiomas smaller than 2 cm and larger tumors.

Tc-99m MDP uptake in osteopoikilosis

A Tc-99m bone scan of a patient with classic roentgenographic findings of osteopoikilosis revealed multiple foci of increased activity that corresponded to many of the sclerotic foci on the roentgenograms. The authors presume that the abnormal bone scan in this patient reflects active osseous remodeling, similar to what has been observed in bone islands. Previous reports have emphasized the critical role of the radionuclide bone scan for distinguishing osteopoikilosis from osteoblastic bone metastases in patients with a known or suspected primary malignancy. In a young patient, an abnormal bone scan does not exclude the diagnosis of osteopoikilosis if the roentgenographic findings are characteristic of that entity.

Tears of the anterior cruciate ligament: primary and secondary signs at MR imaging

To investigate primary and secondary signs of anterior cruciate ligament (ACL) tear at magnetic resonance (MR) imaging, the authors retrospectively reviewed 103 MR imaging examinations obtained in 99 patients, the original interpretations of these examinations, clinical records, and arthroscopy reports. Fifty cases of arthroscopy-documented complete ACL tear were included. The primary signs of ACL tear (ie, abnormal ACL morphologic features or signal intensity) had respective sensitivity and specificity values of 96% (48 of 50 examinations) and 94% (50 of 53) on sagittal images and 92% (46 of 50) and 83% (43 of 52) on coronal images. As a secondary sign of ACL tear, bone bruise involving the lateral compartment of the knee was found in 40% (20 of 50) of cases of ACL tear and in 4% (2 of 53) of cases of normal ACL. The mean curvature of the posterior cruciate ligament was increased (0.40 vs 0.27; P < .0001) in cases of ACL tear. An abnormal appearance of the ACL on sagittal images remains the single most sensitive and specific sign of ACL tear.

Percutaneous needle biopsy of hepatic cavernous hemangioma

In a retrospective review of percutaneous needle biopsy in 38 patients, we assessed the safety of this procedure for establishing the diagnosis of cavernous hemangioma of the liver. Computed tomography (CT) or ultrasound was used to direct the biopsy of focal liver lesions ranging in size from 1 to 13.5 cm, with a median size of 3 cm. In all patients, the pathological diagnosis was established conclusively on the basis of core tissue samples obtained using a 20-gauge cutting needle and an average of 2.7 passes. Biopsy was performed as an outpatient procedure in 31 patients (82%). Clinical or radiological follow-up of 30 patients for an average of 32 months (range 7-57 months) supported the pathological diagnosis of cavernous hemangioma. Despite the reported risk of hemorrhage, we performed biopsies on all patients without serious complication; five patients complained of transient right upper quadrant pain, that did not require treatment. We conclude that percutaneous needle biopsy (PNB) of the liver is a safe and effective procedure for establishing the diagnosis of cavernous hemangioma in patients who have no bleeding diathesis.

Pyocystis with urethral obstruction: percutaneous cystostomy as an alternative to surgery

Three patients with pyocystis and urethral obstruction were successfully treated with percutaneous placement of a suprapubic cystostomy catheter. This approach is an alternative to transurethral bladder irrigation or cystectomy in selected patients.

Spermatic cord sarcomas: sonographic and CT features

Five patients with sarcomas of the spermatic cord were imaged with sonography and/or computed tomography (CT). The former modality is most helpful in demonstrating the extratesticular origin of the mass and evaluating its scrotal extension for local staging. CT is necessary for pelvic staging and searching for distant metastasis. The fat in liposarcomas was easily identified by CT, although it was not echogenic on sonography. Sonography should be the primary imaging modality for scrotal or inguinal masses. If a neoplasm is found, CT should be used for staging, prior to definitive surgical treatment.

Percutaneous gastrostomy with gastropexy: experience in 125 patients

We report our experience with radiologically guided percutaneous tube gastrostomy in 125 patients by using a gastropexy technique in which the anterior gastric wall is nonsurgically sutured to the anterior abdominal wall with percutaneously placed T-fasteners before catheter insertion. Short-term follow-up of up to 2 weeks was available in all patients. In 63 patients, long-term follow-up (greater than 4 weeks; average, 3.5 months; maximum, 1 year) was available. Catheter placement was successful in 124 (99%) of 125 patients, including three patients with anatomic changes after Bilroth II hemigastrectomy and two patients with failed endoscopic attempts. There were no deaths related to the procedure, and no patients required surgical intervention for complications attributable to the gastrostomy procedure. The 30-day mortality rate was 11% (n = 7). These deaths were due to cardiorespiratory arrest and were not attributable to the gastrostomy procedure. Major complications occurred in 1.6% (n = 1) and minor complications in 9.5% (n = 6). These results indicate that percutaneous gastrostomy with gastropexy is a safe and effective technique for placement of catheters in the stomach.

Gallstone fragmentation with contact electrohydraulic lithotripsy: in vitro study of physical and technical factors

To identify physical and technical factors that have an effect on fragmentation, the authors performed in vitro contact electrohydraulic lithotripsy (EHL) on gallstones 10 mm or larger in size. Of 122 gallstones, 113 (93%) could be fragmented with 1-46 pulses from a 3-F electrode (average, 10 pulses). Only 12 of the 113 stones could be fragmented with a single spark. Of the nine stones that did not fragment with 50 pulses from a 3-F electrode, four were larger than 30 mm in diameter, and five were seen at radiography to be heavily calcified; all of these stones were fragmented with five or fewer pulses from a 9-F electrode. Stone capture in a wire basket facilitated fragmentation of gallstones of all sizes, but particularly those stones 15 mm or larger. Contact EHL could be performed as well in a 1:1 dilute diatrizoate irrigating solution as in 1:6 normal saline. A significantly greater number of pulses was required to fragment gallstones 15 mm in diameter or larger compared with stones smaller than 15 mm (P less than .01). In addition, stones 15 mm or smaller had a greater tendency to fragment into "gravel" (ie, fragments measuring 2 mm or less), while EHL of stones larger than 15 mm produced larger, discrete fragments of approximately equal size (P less than .05). EHL of heavily calcified gallstones required a significantly greater number of pulses than EHL of less calcified or noncalcified stones (P less than .002).

Adrenal cysts: imaging and percutaneous aspiration

Six patients with primary adrenal cysts were encountered during a period of 3 years. Multiple imaging modalities were used to characterize these lesions, including magnetic resonance imaging in one case. Percutaneous aspiration was performed on four of the six cysts - in one case, in the operating room prior to excision of the cyst. Cholesterol was detected in four cysts and cortisol in one cyst. Cytologic findings from aspiration biopsy were benign in all five cases. Two cysts were removed, one of them after reaccumulation of the fluid after needle aspiration. The findings in this small series of adrenal cysts suggest that in certain cases, complete cyst aspiration, rather than surgical excision, may be carried out initially for diagnosis and management of indeterminate suprarenal cystic lesions and symptomatic cysts of the adrenal gland.

Routine sonographic techniques fail to quantify gallstone size and number: a retrospective study of 111 surgically proved cases

We analyzed sonographic images retrospectively to determine their value in quantifying gallstone size and number in 111 surgically proved stone-containing gallbladders for which routine preoperative sonograms were available. The number and size of of stones found on pathologic examination were correlated with the results of image analysis. In patients with more than one stone, observable size differences were recorded if the smallest stone diameter was less than 50% of the largest stone diameter. Estimates of gallstone size and number from preoperative sonograms were correct in only 23 (21%) of 111 cases. Stone size and number were overestimated as often as they were underestimated. Stones of a uniform size were recognized correctly in 59 (92%) of 64 cases. Stones of two different sizes were correctly identified in only 14 (30%) of 47 cases; the second, smaller stones were missed in 26 (79%) of 33 cases. These findings indicate poor sonographic characterization of gallbladder contents when imaging studies are performed solely to determine the presence or absence of gallstones.