Jason Handwerker

Sequence-specific MR Imaging Findings That Are Useful in Dating Ischemic Stroke

Patients may present to the hospital at various times after an ischemic stroke. Many present weeks after a neurologic deficit has occurred, as is often the case with elderly patients and those in a nursing home. The ability to determine the age of an ischemic stroke provides useful clinical information for the patient, his or her family, and the medical team. Many times, perfusion imaging is not performed, and pulse sequence-specific magnetic resonance (MR) imaging findings may help determine the age of the infarct. The findings seen at apparent diffusion coefficient mapping and diffusion-weighted, fluid-attenuated inversion recovery (FLAIR) and unenhanced and contrast material-enhanced T1- and T2-weighted gradient-echo and susceptibility-weighted MR imaging may help determine the relative age of a cerebral infarct. Strokes may be classified and dated as early hyperacute, late hyperacute, acute, subacute, or chronic. Recent data indicate that in many patients with restricted diffusion and no change on FLAIR images, it is more likely than was initially thought that the stroke is less than 6 hours old. The time window to administer intravenous tissue plasminogen activator is currently 4.5 hours from the time when the patient was last seen to be normal, and for anterior circulation strokes, the time window for administering intraarterial tissue plasminogen activator is 6 hours from when the patient was last seen to be normal. For this reason, accurate dating is important in patients with ischemic stroke.

MDCT Angiography of Acute Chest Pain: Evaluation of ECG-Gated and Nongated Techniques

OBJECTIVE The objective of our study was to compare MDCT angiography protocols used in patients with acute chest pain caused by vascular, nonvascular, and cardiac abnormalities. SUBJECTS AND METHODS In four groups of 20 patients with chest pain each, four MDCT protocols were used based on monitoring vascular attenuation: pulmonary embolism (150 H at pulmonary artery), aortic dissection (200 H at aortic arch), chest pain (200 H at pulmonary artery), and chest pain with ECG gating (150 H at pulmonary artery). Vascular enhancement was assessed by attenuation measurements taken from locations in the pulmonary artery (n = 3) and thoracic aorta (n = 4). The appearance of the coronary artery in regard to opacification and motion was assessed on a scale of 1 to 5 (best). RESULTS The mean pulmonary artery and aorta attenuation (372 H and 352 H, respectively) was significantly higher (p < 0.005, Students t test) and the number of vessel attenuation points measuring less than 200 H (1/140) was significantly smaller (p < 0.001, chi-square test) in the chest pain compared with the dissection (318 H, 310 H; 16/140), gated chest pain (304 H, 286 H; 17/14), and pulmonary embolism (302 H, 220 H; 28/140) groups. The median coronary artery visualization score was 4; the proximal regions received a significantly (p < 0.005, Mann-Whitney test) higher grade compared with the middle and distal regions (medians, 5, 4, and 2, respectively). Artifacts were noted on the gated scans. CONCLUSION The chest pain protocol can be used to assess both the pulmonary arteries and the thoracic aorta, whereas the ECG-gating protocol appears to be a promising adjunct for a comprehensive single chest pain protocol.

Cryptogenic stroke and the left atrial septal pouch: a case report.

The left atrial septal pouch (LASP) is an anatomic variant of the interatrial septum and may be a nidus for thromboembolism. We present the case of a 49 year-old man without known vascular risk factors who experienced bi-hemispheric strokes over the course of 10 days, suggestive of multiple emboli. Transesophageal echocardiography revealed a prominent LASP. We suggest that presence of LASP was a likely cause of stroke in this patient and that further study of a possible association between LASP and ischemic stroke in younger individuals may be warranted.

Neuroimaging findings of the post-treatment effects of radiation and chemotherapy of malignant primary glial neoplasms.

Post-treatment radiation and chemotherapy of malignant primary glial neoplasms present a wide spectrum of tumor appearances and treatment-related entities. Radiologic findings of these post-treatment effects overlap, making it difficult to distinguish treatment response and failure. The purposes of this article are to illustrate and contrast the imaging appearances of recurrent tumor from necrosis and to discuss other radiologic effects of cancer treatments. It is critical for radiologists to recognize these treatment-related effects to help direct clinical management.

Cerebral microbleeds and cognitive decline in a hemodialysis patient: Case report and review of literature

Cerebral microbleeds (CMBs) are small hemosiderin deposits indicative of prior cerebral microscopic hemorrhage and previously thought to be clinically silent. Recent population‐based cross‐sectional studies and prospective longitudinal cohort studies have revealed association between CMB and cognitive dysfunction. In the general population, CMBs are associated with age, hypertension, and cerebral amyloid angiopathy. In the chronic kidney disease (CKD) population, diminished estimated glomerular filtration rate has been found to be an independent risk factor for CMB, raising the possibility that a uremic milieu may predispose to microbleeds. In the end‐stage renal disease (ESRD) population on hemodialysis, the incidence of microbleeds is significantly higher compared with a control group without history of CKD or stroke. We present an ESRD patient on chronic hemodialysis with a history of gradual cognitive decline and progressive CMBs. Through this case and literature review, we illustrate the need to develop detection and prediction models to treat this frequent development in ESRD patients.

A Novel Model to Test Accuracy and Reproducibility of MDCT Scan Protocols for Coronary Calcium in Vivo

Objectives: We compared the accuracy and reliability of prospectively triggered, retrospectively ECG gated, and non-gated CT image reconstruction for measurements of coronary artery calcification (CAC) in vivo using a novel animal model. Materials and Methods: In six Yorkshire farm pigs, prefabricated chains of cortical bone fragments were sutured over the epicardial bed of the major coronary arteries. Using a 4-slice MDCT scanner, each animal was imaged with two different protocols: sequential acquisition with prospective ECG triggering, and spiral acquisition with retrospectively ECG gated image reconstruction- non-gated reconstructions were also generated from these latter scans. Two independent observers measured the ‘Agatston score’ (AS), the calcified volume (CV), and mineral mass (MM). To calculate accuracy of MM measurements the ash weight of the burned bone fragments was compared to MDCT derived MM. Results: Six pigs successfully underwent surgery and CT imaging (mean heart rate: 86 ±12 bpm). MM measurements from prospectively ECG triggered CT sequential scans were more accurate (p<0.02) and reproducible (p=0.05) than sequential CT scans without ECG triggering or spiral acquisition using retrospective ECG gating. Conclusions: At high heart rates prospective ECG triggered image reconstruction is more accurate and reproducible for CAC scoring than retrospective ECG gated reconstruction and non-gated reconstruction.

Carotid laceration during myringotomy

Vascular injury during myringotomy and tympanostomy tube placement is a rare complication. When the internal carotid artery deviates from its normal course within the temporal bone, it is at increased risk for inadvertent injury. We present a case approved by our Institutional Review Board of an internal carotid artery (ICA) injury in a child undergoing myringotomy to illustrate this point and to report a unique complication resulting from its management. A healthy seven-year-old child with recurrent right otitis media with effusion was taken to the operating room at an outside institution for a myringotomy and insertion of tympanostomy tube. A radially oriented myringotomy was made in the anterior inferior quadrant of the tympanic membrane (TM) which resulted in severe bleeding. Hemostasis was achieved by packing the ear canal with gelfoam and Sepragel followed by an external mastoid dressing. She developed a second bleed and was transferred to the Massachusetts Eye & Ear Infirmary. Computed tomography scan with contrast showed aberrant ICAs coursing through the middle ears on the right (Fig 1) as well as the left side. She was emergently transported to the neurointerventional radiology suite, where angiography revealed a 3-mm pseudoaneurysm of the petrous segment of the aberrant right ICA. There was good collateral flow via the anterior communicating artery from the left ICA and from the right posterior communicating artery from the vertebrobasilar circulation. Coil embolization of the right ICA was then performed, both distal and proximal to the affected segment. She was placed on heparin and transferred to the pediatric intensive care unit, where she remained neurologically intact and without any further bleeding, and was discharged to home the following day. At three-month follow-up, she was noted on otoscopy to have extrusion of the coil from the lumen of the occluded right ICA (Fig 2), which tented up the TM and caused a conductive hearing loss. She was taken to the operating room and a tragal cartilage perichondrial graft was placed between the tympanic membrane and the carotid artery. At follow-up, she had a well-healed graft

A Patient With Cough and Dysphagia

A woman in her 60s with no clinically significant medical history presented with a several-month history of coughing and food getting stuck in her throat after eating. The patient denied food regurgitation, respiratory difficulties, history of aspiration pneumonia, or weight loss. No abnormalities were noted on physical examination of the head and neck or on flexible laryngoscopy. A gastroenterologist had previously performed an esophagoscopy, findings of which were significant for an esophageal pouch and preliminary diagnosis of Zenker diverticulum. Barium swallow was performed, and lateral and anteroposterior views are shown in Figure, A and B, respectively. The patient desired surgical treatment for this lesion. In the operating room, rigid esophagoscopy was performed. The cricopharyngeus muscle was noted, and a lateral pouch was identified (Figure, C). What is your diagnosis? A

Case records of the Massachusetts General Hospital. Case 34-2009. A 20-year-old man with sore throat, fever, and rash.

Dr. Robert W. McGarrah (Medicine): A 20-year-old man was admitted to this hospital because of sore throat, fever, and a diffuse rash. The patient had been well until approximately 4 weeks earlier, when sore throat developed. On examination by his internist, vital signs were normal, the temperature was 36.8°C, and there was pharyngeal erythema without cervical lymphadenopathy. A rapid streptococcal-antigen test was negative. The next day, he felt better. One week before admission, sore throat and fever recurred, and the patient returned to his internist the next day. The temperature was 37.1°C and the pulse 102 beats per minute; he appeared well. The tonsils were enlarged (3+), with exudate and petechiae, and there was shotty bilateral cervical lymphadenopathy. A rapid test for streptococcal pharyngitis and a blood test for mononucleosis were negative. Amoxicillin–clavulanate was prescribed. The next day, 1 day after beginning the antibiotic therapy, a flat, red, even, itchy rash developed on the medial surface of his right arm, which he thought was poison ivy. During the next 3 days, the lesions became raised, enlarged, and painful and spread from his arms to his legs, back, hands, feet, and perioral area, without mucosal involvement. He took ibuprofen for the pain. Two days before admission, the patient returned to his primary care provider, who noted a generalized papular rash and sent him to the emergency department of a hospital near his home. Repeat testing for streptococcal pharyngitis was negative. Results of other tests are shown in Table 1. The administration of antibiotics was stopped, and a prednisone taper (starting dose, 40 mg) was begun. The fevers resolved, but the sore throat and rash persisted and then worsened; he saw his internist, who sent him to the emergency department of this hospital. The patient reported that the rash had evolved to large, painful, hemorrhagic vesicles and bullae that covered most of his body surface; the bullae frequently ruptured, leaking blood and clear fluid. He had odynophagia for solid foods, mild fatigue, swollen lymph nodes in his neck, and loose stools for approximately 4 days. He reported a weight loss of approximately 3 kg, because of pain and difficulty swallowing solids. He did not have headache, stiff neck, confusion, cough, rhinorrhea, abdominal pain, nausea, vomiting, joint aches or effusions, or difficulty breathing. He had had varicella as a child, and he reported that the lesions had appeared smaller and more diffuse than the current presentation. He had a history of alCase 34-2009: A 20-Year-Old Man with Sore Throat, Fever, and RashA 20-year-old man was admitted to this hospital because of sore throat, fever, and a diffuse rash for 1 week. Testing for streptococcal pharyngitis and mononucleosis was negative. Amoxicillin and clavulanate were prescribed, and the next day, a red, itchy rash developed on the medial surface of his right arm; the lesions became raised, enlarged, and painful and spread from his arms to his legs, back, hands, feet, and perioral area, without mucosal involvement. Examination disclosed a diffuse eruption of tender violaceous-pink papulovesicles, which progressed to hemorrhagic crusting. A diagnostic procedure was performed.

Early Hemodynamic Response Assessment of Stereotactic Radiosurgery for a Cerebral Arteriovenous Malformation Using 4D Flow MRI

SUMMARY: Brain AVMs treated with stereotactic radiosurgery typically demonstrate a minimum latency period of 1–3 years between treatment and nidus obliteration. Assessment of treatment response is usually limited to evaluation of AVM nidus structural changes using conventional MR imaging and MRA techniques. This report describes the use of 4D Flow MRI to also measure radiation-induced hemodynamic changes in a Spetzler-Martin grade III AVM, which were detectable as early as 6 months after treatment.