Ammar Chaudhry

Necrotizing fasciitis and its mimics: what radiologists need to know.

OBJECTIVEnThe purpose of this article is to review the imaging features of necrotizing fasciitis and its potential mimics. Key imaging features are emphasized to enable accurate and efficient interpretation of variables that are essential in appropriate management.nnnCONCLUSIONnNecrotizing fasciitis is a medical emergency with potential lethal outcome. Dissecting gas along fascial planes in the absence of penetrating trauma (including iatrogenic) is essentially pathognomonic. However, the lack of soft-tissue emphysema does not exclude the diagnosis. Mimics of necrotizing fasciitis include nonnecrotizing fasciitis (eosinophilic, paraneoplastic, inflammatory (lupus myofasciitis, Churg-Strauss, nodular, or proliferative), myositis, neoplasm, myonecrosis, inflammatory myopathy, and compartment syndrome. Necrotizing fasciitis is a clinical diagnosis, and imaging can reveal nonspecific or negative findings (particularly during the early course of disease). One should be familiar with salient clinical and imaging findings of necrotizing fasciitis to facilitate a more rapid and accurate diagnosis and be aware that its diagnosis necessitates immediate discussion with the referring physician.

Utility of positron emission tomography-magnetic resonance imaging in musculoskeletal imaging

Differentiation between neoplastic and nonneoplastic conditions magnetic resonance imaging (MRI) has established itself as one of the key clinical tools in evaluation of musculoskeletal pathology. However, MRI still has several key limitations which require supplemental information from additional modalities to complete evaluation of various disorders. This has led to the development hybrid positron emission tomography (PET)-MRI which is rapidly evolving to address key clinical questions by using the morphological strengths of MRI and functional information of PET imaging. In this article, we aim to review physical principles and techniques of PET-MRI and discuss clinical utility of functional information obtained from PET imaging and structural information obtained from MRI imaging for the evaluation of musculoskeletal pathology. More specifically, this review highlights the role of PET-MRI in musculoskeletal oncology including initial diagnosis and staging, treatment planning and post-treatment follow-up. Also we will review utility of PET-MRI in evaluating musculoskeletal infections (especially in the immunocompromised and diabetics) and inflammatory condition. Additionally, common pitfalls of PET-MRI will be addressed.

Assessment of isotropic calcium using 0.5-mm reconstructions from 320-row CT data sets identifies more patients with non-zero Agatston score and more subclinical atherosclerosis than standard 3.0-mm coronary artery calcium scan and CT angiography

BACKGROUNDnThe presence of calcified plaque in coronary arteries can be quantified by using 0.5-mm isotropic reconstructions from 320-row CT without increased radiation dose. Little is known about reclassification of patients with non-zero Agatston scores and quantitative measures of calcified plaque using 0.5-mm reconstructions.nnnOBJECTIVEnThe aim was to compare proportions of zero vs. non-zero Agatston scores (subclinical atherosclerosis) in 0.5-mm isotropic reconstructions vs. standard 3.0-mm and CT angiography (CTA) scans on 320-row CT.nnnMETHODSnProspectively, we quantified calcified plaque in coronary arteries in 104 patients by using non-contrast-enhanced scans with 0.5 and 3.0 mm. Coronary calcium assessment was determined by 2 observers. Clinically indicated CTA was also performed; coronary calcium assessment findings were compared with CTA. Ranked Wilcoxon test and χ2 test were performed for comparison. Reproducibility for proportion of zero vs non-zero was assessed by κ statistics.nnnRESULTSnMedian Agatston score (41.9 [interquartile range (IQR), 3.7-213.6] vs. 5.2 [IQR, 0.0-128.5]), calcium volume (53.6 mm3 [IQR, 8.1-202.3] vs. 5.1 mm(3) [IQR, 0.0-96.8],), and lesion number (10.0 [IQR, 3.5-18.5] vs. 1.0 [IQR, 0.0-6.0]) were significantly higher on 0.5-mm reconstruction (P < .0001) than on 3.0-mm reconstruction. More patients with subclinical atherosclerosis were detected on 0.5 mm than on 3.0 mm and CTA scans (76.9% vs. 53.8% vs. 54.8%; P < .0001). The κ values for inter-rater agreement were 0.94 and 0.52 on 3.0- and 0.5-mm data sets, respectively. However, when Agatston scores < 10 were excluded from analysis, the κ value rose to 0.83.nnnCONCLUSIONnIsotropic 0.5-mm reconstruction detected 23.1% and 22.1% more patients with subclinical atherosclerosis than standard 3.0-mm scans and CTA, which may be more sensitive for the detection of subclinical atherosclerosis; its potential clinical utility needs to be validated in large, prospective studies.

Isolated Fallopian Tube Torsion: A Case Report and Review of Literature

Isolated fallopian tube torsion is a rare cause of pelvic pain in female patients. We present the case of a 10 year old female without significant past medical history who presented with acute left lower quadrant abdominal pain. A CT scan of the abdomen/pelvis showed a dilated, tortuous, fluid-filled structure in the left adnexal region which was ultimately diagnosed as a torsed fallopian tube. Subsequent trans abdominal ultrasound examination documented the fallopian tube’s lack of vascularity with color Doppler and demonstrated thickened, edematous walls and longitudinal folds. The ipsilateral ovary maintained normal vascularity and was unremarkable. The patient underwent laparoscopic salpingectomy, and pathologic examination of the specimen confirmed hemorrhagic fallopian tube necrosis. The patient recovered without complication, and has not experienced any pain recurrence since the procedure.

Cryoneurolysis in Patients with Refractory Chronic Peripheral Neuropathic Pain

PURPOSEnTo evaluate the safety and efficacy of cryoneurolysis in patients with refractory peripheral neuropathic pain.nnnMATERIALS AND METHODSnTwenty-two patients referred for cryoneurolysis of refractory peripheral neuropathy were recruited prospectively from July 2011 to July 2013. The mean patient age was 49.5 years, and 41% of patients were female. Ultrasound imaging of the involved nerves was used for guidance. Percutaneous ablations were performed with a PerCryo 17R device. Pain levels were recorded on a visual analog scale (scores 0-10) before and at 1, 3, 6, 9, and 12 months after the procedure, and complications were documented.nnnRESULTSnMean pain levels were 8.3 ± 1.9 before intervention and 2.3 ± 2.5 at 1 month, 3.2 ± 2.5 at 3 months, 4.7 ± 2.7 at 6 months, and 5.1 ± 3.7 at 12 months afterward. A Wilcoxon rank-sum test was performed and showed a statically significant decrease between pre- and postprocedural pain scores. There were no complications from the procedures.nnnDISCUSSIONnCryoneurolysis caused a significant decrease in self-reported pain scores in patients with chronic refractory neuropathic pain, with moderately long-term relief. Cryoneurolysis is an additional therapy that can alleviate severe chronic neuropathic pain.

Qualitative assessment of diffusion weighted imaging and susceptibility weighted imaging of myeloid sarcoma involving the brain

Background and Purpose Myeloid sarcoma is a rare form of extramedullary leukemia, which can present with or without systemic leukemia. The purpose of this study was to evaluate characteristic computed tomography (CT) and magnetic resonance imaging (MRI) findings (including diffusion weighted imaging and susceptibility weighted imaging) of myeloid sarcoma involving the brain. Materials and Methods One hundred nine patients with pathologically proven myeloid sarcoma underwent pretreatment CT and MRI, which were retrospectively reviewed. Computed tomography and MRI characteristics reviewed include lesion location, shape, size, architecture, margins, ±multiplicity, ±bone destruction, pattern and degree of enhancement, ±restricted diffusion, and ±susceptibility artifact. Results Twenty-five patients (14 men, 11 women; mean age, 55 years; range, 9–80 years) met the inclusion criteria. Acute myeloid leukemia with subtypes M3 (44.4%) and M5 (22.2%) were the most common. On unenhanced CT, mean lesion size was 1.9 ± 0.4cm; 60% were intra-axial hyperdense masses, 8% were intraventricular hyperdense masses, 12% were isodense intra-axial masses, and 20% of cases were extra-axial hyperdense nodular masses. There was no observable intralesional or perilesional calcium. On MRI, mean lesion size was 2.1 ± 0.6cm. The lesions were isointense (80%) or hypointense (20%) on T1-weighted images with homogeneous (88%) or heterogeneous (12%) enhancement. On fluid-attenuated inversion recovery and T2-weighted images, lesions were hyperintense (96%) or isointense (4%) with mild vasogenic edema. Majority (96%) of cases demonstrated restricted diffusion, whereas only a few (16%) demonstrated susceptibility artifact. Conclusions In patients with history of leukemia or myeloproliferative disorder, identification of homogenous mass hyperdense on unenhanced CT, T1 isointense, and T2/fluid-attenuated inversion recovery hyperintense with restricted diffusion and homogenous postcontrast enhancement without significant susceptibility artifact is suggestive of myeloid sarcoma.

Ectopic craniopharyngioma of the fourth ventricle in a patient with Gardner syndrome.

Ectopic craniopharyngioma is uncommon and a craniopharyngioma confined purely within the fourth ventricle is extremely rare. We report a craniopharyngioma of the fourth ventricle in a 20-year-old man with Gardner syndrome. Imaging characteristics of craniopharyngiomas and fourth ventricle lesions are discussed with a review of the literature regarding the pathogenesis of craniopharyngiomas and the possible association with Gardner syndrome.

Computed Tomography Assessment of Ablation Zone Enhancement in Patients With Early-Stage Lung Cancer After Stereotactic Ablative Radiotherapy.

Introduction Stereotactic ablative radiotherapy (SABR) offers a curative treatment for lung cancer in patients who are marginal surgical candidates. However, unlike traditional surgery the lung cancer remains in place after treatment. Thus, imaging follow-up for evaluation of recurrence is of paramount importance. Materials and Methods In this retrospective designed Institutional Review Board-approved study, follow-up contrast-enhanced computed tomography (CT) exams were performed on sixty one patients to evaluate enhancement pattern in the ablation zone at 1, 3, 6, and 12 months after SABR. Results Eleven patients had recurrence within the ablation zone after SABR. The postcontrast enhancement in the recurrence group showed a washin and washout phenomenon, whereas the radiation-induced lung injury group showed continuous enhancement suggesting an inflammatory process. Conclusions The textural feature of the ablation zone of enhancement and perfusion as demonstrated in computed tomography nodule enhancement may allow early differentiation of recurrence from radiation-induced lung injury in patients status after SABR or primary lung cancer.

Atypical presentation of CLIPPERS syndrome: A new entity in the differential diagnosis of central nervous system rheumatologic diseases

AbstractNumerous autoimmune diseases can affect the central nervous system (CNS), and variable clinical presentations confound the differential diagnosis. The challenging task of properly characterizing various CNS autoimmune diseases enables patients to be rapidly triaged and appropriately treated. In this review article, we aim to explore different CNS manifestations of rheumatologic diseases with emphasis on the utility of imaging and cerebrospinal fluid findings. We review the classic physical examination findings, characteristic imaging features, cerebrospinal fluid results, and serum biomarkers. In addition, we also present a unique case of newly described autoimmune entity CLIPPERS syndrome. Our case is unique in that this is the first case which demonstrates involvement of the supratentorial perivascular spaces in addition to the classic infratentorial involvement as initially described by Pittock et al (Brain. 2010;133:2626–2634).

Characteristic CT Findings After Percutaneous Cryoablation Treatment of Malignant Lung Nodules.

Abstract Assess computed tomography (CT) imaging characteristics after percutaneous cryotherapy for lung cancer. A retrospective IRB-approved analysis of 40 patients who underwent nonsurgical treatment for primary stage 1 lung cancer performed from January 2007 to March 2011 was included in this study. All procedures were performed using general anesthesia and CT guidance. Follow-up imaging with CT of the chest was obtained at 1 month, 3 months, 6 months, and 12 months postprocedure to evaluate the ablated lung nodule. Nodule surface area, density (in Hounsfield units), and presence or absence of cavitations were recorded. In addition, the degree of nodule enhancement was also recorded. Patients who were unable to obtain the aforementioned follow-up were excluded from the study. Thirty-six patients underwent percutaneous cryoablation with men to women ratio of 75% with mean age for men 74.6 and mean age for women 74.3 years of age. The average nodule surface area preablation and postcryoablation at 1-, 3-, 6-, and 12-month follow-ups were 2.99, 7.86, 3.89, 3.18 and 3.07[REPLACEMENT CHARACTER]cm2, respectively. The average precontrast nodule density before cryoablation was 8.9 and average precontrast nodule density postprocedure at 1, 3, 6, and 12 months follow-ups were 8.5, −5.9, −9.4, and −3.8 HU, respectively. There is increased attenuation of lung nodules over time with an average postcontrast enhancement of 11.4, 18.5, 16.1, and 25.7 HU at the aforementioned time intervals. Cavitations occurred in the cryoablation zone in 53% (19/36) of patients. 80.6% (29/36) of the cavitations in the cryoablation zone resolved within 12 months. Four patients (11%) had recurrence of tumor at the site of cryoablation and none of the patients had satellite or distant metastasis. Our study shows that patients who underwent cryotherapy for lung nodules treatment had characteristic changes on follow-up CT including. The surface area of the nodule increases at the 1-month follow-up with subsequent gradual decrease in the surface area. Decreased nodule density (Hounsfield units) at each interval follow-up is associated with complete ablation of the lung cancer whereas increasing nodule density was suggestive of recurrence. Cavity formation within the region of the ablated nodule, most of which typically resolved within the first 3 to 6 months. Nodule enhancement is difficult to assess because of the limited data sets that are available.