Focal Low Density Research Articles

7962 Transformation of Poorly Differentiated Papillary Thyroid Carcinoma to Anaplastic Thyroid Carcinoma, an Atypical Course!

Abstract Disclosure: T. Altaweel: None. S. Makadsi: None. M. Hussein: None. J. Samantray: None. Introduction: Anaplastic thyroid cancers are undifferentiated, rare and aggressive. The transformation of papillary thyroid cancer to anaplastic thyroid cancer is documented in literature, however, rare. In this report, we present a case of Anaplastic thyroid carcinoma likely arising from a co-existing poorly differentiated Papillary carcinoma. Case Presentation: A 74-year-old male with past medical history of tobacco smoking who presented with the onset of voice hoarseness for 6 months. He has also noticed a left neck mass that is in the mid supraclavicular region. A Neck CT neck was performed at the time of presentation and was significant for a 4.6x3.4x5.9 cm left thyroid mass with displacement of the trachea. FNA biopsy showed papillary carcinoma with focal features of Tall Cell Variant. Poorly differentiated components with fragments of stroma and muscle were seen and suggested invasion. These findings raised the possibility of anaplastic thyroid carcinoma in the setting of papillary carcinoma and poorly differentiated carcinoma. BRAF V600E pathogenic variant mutation along with TERT mutation were found. Patient underwent direct laryngoscopy, bronchoscopy with biopsies, and tracheostomy with surgical pathology confirming papillary thyroid cancer with muscles invasion. Combination dabrafenib and trametinib were started. No surgical resection of thyroid tissue was planned. A follow up CT showed a significant decrease in the low-density soft tissue involving the medial thyroid gland bilaterally, consistent with interim positive response to therapy. Three months later, CT neck showed near complete resolution of low-density soft tissue involving the medial thyroid and parathyroid glands and subglottic trachea consistent with further interim positive response to therapy. Six months post initiation of therapy, CT Neck showed focal low density in the mid and inferior right thyroid gland which may represent residual and/or recurrent thyroid carcinoma. That density was further demonstrated on a repeat CT neck as a 1.8 cm hypodense nodule in the inferior right thyroid gland and concerning for recurrent thyroid tumor with possible infiltration of the trachea. Conclusion: ATC prognosis is affected by many factors such as metastasis, age, treatment strategies, socioeconomic status and the presence of BRAF V600E and TERT mutations. Diagnosis can be challenging. Our patient presented months after his symptoms started and this is an atypical course of Anaplastic Thyroid Carcinoma as it usually progresses aggressively and rapidly. Given the pathology reports and the more slow presentation of this patient’s carcinoma, it can be suggested that this is a case of papillary carcinoma with a later transformation to ATC. In these cases, surgical resection Presentation: 6/2/2024

PULMONARY AND SPLENIC SARCOIDOSIS MIMICKING LYMPHOMA

SESSION TITLE: Medical Student/Resident Pulmonary Manifestations of Systemic Disease 3 SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: Sarcoidosis is a chronic multisystem disease of unknown etiology. It is characterized by noncaseating granulomas mainly involving lungs but any organ might be affected. As a diagnosis of exclusion extrapulmonary sarcoidosis might be challenging to diagnose based on the site of involvement. Here a case of pulmonary and splenic Sarcoidosis is presented that was mimicking lymphoma (1). CASE PRESENTATION: 51 Y.O F with PMH of ADHD, beta thalassemia, morbid obesity, former smoker stopped 15 years ago and left hip OA s/p replacement was referred to pulmonary clinic for abnormal CT findings. Physical exam was benign and she did not have any active complaints. CT chest was remarkable for multiple bilateral nodular and ground glass opacities measuring up to 5-6 mm, mild diffuse mediastinal and bilateral hilar lymphadenopathy measure up to 47 x 18 mm with focal low density changes suggestive of cystic or necrotic components. CT abdomen revealed enlarged spleen with multiple hypodense lesions measuring up to 21 mm and a stable left renal cyst. Labs were noticeable for Normal ACE level, microcytic anemia, negative quantiferon, normal LDH and the rest were unremarkable. Lymphoma and sarcoidosis at this time were on the top of differential diagnosis list. Bronchoscopy was done with EBUS and transbronchial biopsy revealed noncaseating granulomatous inflammation suggestive of sarcoidosis with no evidence of malignancy. With impression of pulmonary and extra pulmonary sarcoidosis she was started on prednisone. 4 months later patient stopped the prednisone on her own since she was gaining weight so she was stared on methotrexate. Interval changes were followed with CT imaging that was significant for resolution of some of the pulmonary opacities with no increase in the size of remaining. Mediastinal and hilar lymphadenopathy resolved and size of lesions in spleen decreased. Patient remained asymptomatic and is still following up for further management. DISCUSSION: In more than 90 % of patients with sarcoidosis pulmonary involvement was reported. Ocular, lymph-node, and cutaneous findings are the more frequent involved organ systems respectively. more than 50% of cases has co existing pulmonary and extra pulmonary manifestations while only 2% of patients present with isolated extra pulmonary sarcoidosis (2). Prednisone is considered the first-line therapy. Side effects of chronic steroid use and lack of response are limiting factors that can cause significant morbidity in long term treatments. Steroid sparing treatments are increasingly used in these instances. Methotrexate is the disease-modifying antisarcoid drugs that is usually used by most sarcoidosis experts (3). CONCLUSIONS: Extra pulmonary sarcoidosis is mainly coexistent with pulmonary disease. lymphoma is on the differentials with splenic and lymph node involvement and biopsy is needed to confirm and exclude the other possibilities. Reference #1: Baughman RP, Teirstein AS, Judson MA, et al. Clinical characteristics of patients in a case control study of sarcoidosis. Am J Respir Crit Care Med. 2001;164(10 Pt 1):1885–1889. Reference #2: Valeyre D, Prasse A, Nunes H, Uzunhan Y, Brillet PY, Müller-Quernheim J. Sarcoidosis. Lancet. 2014;383(9923):1155–1167. Reference #3: Korsten P, Mirsaeidi M, Sweiss NJ. Nonsteroidal therapy of sarcoidosis. Curr Opin Pulm Med. 2013;19(5):516–523. DISCLOSURES: No relevant relationships by Jonathan Arnedo, source=Web Response No relevant relationships by Sara Khademolhosseini, source=Web Response No relevant relationships by Seyedmohammad Pourshahid, source=Web Response No relevant relationships by Theo Trandafirescu, source=Web Response

Misdiagnosis of an α-fetoprotein-producing esophageal carcinoma: A case report and literature review.

α-fetoprotein (AFP)-producing esophageal carcinoma is a rare type of esophageal cancer, with its characteristics not yet fully clarified. In the present study, a case of esophageal carcinoma was misdiagnosed as an AFP-producing esophageal carcinoma. The patient was a 50-year-old woman who was referred to Qianfoshan Hospital Affiliated to Shandong University in November 2014 with a 3-month history of progressive dysphagia. A chest computed tomography (CT) scan showed thickening of the wall of the esophagus, corresponding regions of luminal stenosis and massive lymph node swelling around the lesser curvature of the esophagus. A laboratory investigation showed that the serum AFP levels of the patient were elevated to 18.97 ng/ml (normal range <12 ng/ml). These laboratory investigation findings combined with the aforementioned pathological diagnosis supported a diagnosis of AFP-producing esophageal carcinoma. An abdominal ultrasound was performed and a cystic low-density measuring 5×4 mm was identified. No metastases were revealed in the liver. The boundary of the focal low density was clear, which indicated a clinical diagnosis of liver cyst. A radical esophagectomy was performed on December 5, 2014. Microscopically, the tumor was a moderately differentiated squamous cell carcinoma invading the serous layer, with no hepatoid features. Immunohistochemistry showed that the cells were diffusely negative for AFP expression. Histopathological examination revealed the absence of hepatoid features. According to these findings, the tumor was diagnosed as a moderately differentiated squamous cell carcinoma. In the present study, the case of a patient with squamous cell carcinoma that was misdiagnosed as an α-fetoprotein-producing esophageal carcinoma was reported, with a review of the literature.

Fabrication of drug-loaded tissue engineering scaffold and its curative effect for chronic osteomyelitis in rabbits

Objective To investigate the anti-infection and bone repair effects of composite scaffolds encapsulated with vancomycin and bone morphogenetic protein-2 (BMP-2). Methods Chitosan (CS) solution and nano-hydroxyapatite (n-HAP) mixed in a ratio of 1∶1 were made into solid materials by freeze drying technology, and immerged into BMP-2/polylactic acid (PLA) and vancomycin/PLA microsphere solution to fabricate drug-loaded scaffolds. Efficiency of drug release was measured. After the induction of chronic infectious tibial bone defect, 60 New Zealand white rabbits were assigned to isolate debridement group (Group Ⅰ), n-HAP/CS scaffold group (Group Ⅱ), n-HAP/CS + vancomycin/PLA group (Group Ⅲ) and n-HAP/CS + vancomycin/PLA+ BMP-2/PLA group (Group Ⅳ) according to the random number table, with 15 rabbits per group. After 8 weeks of treatment, X-ray filming, Norden score, HE staining and marrow culture were performed to evaluate the anti-infection ability and bone repair ability in each group. Results Pore size of the n-HAP/CS scaffold constructed in this study ranged from 80 to 270 μm (mean, 146. 53 μm). Biomechanical test showed the elastic modulus of the scaffold material was (27. 50±1.58)MPa and the compressive strength was (0. 75±0. 04)MPa. BMP-2/PLA and vancomycin/PLA microspheres into ball shape uniformly distributed on the scaffold pores. Drug-loaded scaffold showed relatively stable release of vancomycin and BMP-2 in a period of 18 days. With the extended time amount of the drug release gradually reduced. On the X-ray films 8 weeks after the treatment, sinus formation was visible in groups Ⅲ and Ⅳ, and emergence of periosteal reaction with focal low density shadow was demonstrated in groups Ⅰ and Ⅱ. Norden scores of groups Ⅰ, Ⅱ, Ⅲ and IV were (2.64±0.33) points, (2.63±0.36) points, (1.14±0.29) points and (0.89±0.42) points respectively, indicating group Ⅳ ranked the lowest compared with other three groups (P<0. 05) and group Ⅲ showed significant difference in comparison with groups Ⅰ and Ⅱ (P<0. 05). HE staining showed massive infiltration of inflammatory cells and destroyed bone trabeculas in groups Ⅰ and Ⅱ, trabecular bone arranged neatly in groups Ⅲ and Ⅳ, and thicker trabecular bone in group IV than in group Ⅲ. Marrow culture showed obvious pale yellow colony formation in groups Ⅰ and Ⅱ, but no colony formation in groups Ⅲ and Ⅳ. Conclusions Vancomycin/ BMP-2-loaded tissue engineering scaffolds are constructed successfully. Drug-loaded n-HAP/CS composite scaffold is identified as an ideal implant material for treatment of chronic osteomyelitis in rabbits Key words: Tissue engineering; Hydroxyapatites; Chitosan; Stents; Osteomyelitis

Thin-section CT of the mediastinum in preoperative N-staging of non-small cell lung cancer: Comparison with FDG PET

Purpose To compare diagnostic capability of preoperative N-staging of lung cancer between thin-section CT of the mediastinum and FDG PET, and 5 mm slice thickness CT. Materials and methods The subjects were 34 patients with lung carcinoma who were examined by both CT and PET, and subsequently underwent surgery between May 2005 and January 2007. CT was carried out with a 16 detector row helical CT scanner. The raw data were reconstructed into 5 mm slice thickness and 1 mm slice thickness (thin-section CT). A total of 251 lymph node stations were retrospectively assessed for the presence of lymph node metastasis with thin-section CT, 5 mm CT and PET. In the interpretations of thin-section CT and 5 mm CT, we employed multi-criteria as follows: nodular calcification and intranodal fat as benign criteria, and short-axis diameter more than 10 mm (size criterion), focal low density other than fat, surrounding fat infiltration and convex margin in hilar lymph nodes, as malignant criteria. On PET, maximum standardized uptake value (SUVmax) of 2.5 or more was used as the criterion of malignancy. Sensitivity and specificity were compared between these examinations using McNemar test. Results Sensitivities and specificities of thin-section CT, 5 mm CT and PET were 25%, 25%, 25%, and 97%, 94%, 98%, respectively. The statistical analysis revealed that the specificity of 5 mm CT was significantly lower than those of thin-section CT ( p = 0.039) and PET ( p = 0.006), while no difference was present between thin-section CT and PET. Conclusion Thin-section CT of the mediastinum using multiple criteria was comparable to PET in preoperative N-staging of lung cancer.

Predictive Value of the Pre-Operative CT Scan for Splenectomy in Patients with Primary, and Post Essential Thrombocythemia/Post Polycythemia Vera Myelofibrosis.

BACKGROUND: Splenectomy is performed for palliating symptoms in patients with primary myelofibrosis (PMF; as well as post essential thrombocythemia myelofibrosis/ post polycythemia myelofibrosis (Mesa et. al. Cancer 2006; 107(2):361–70). Pre-operative computed tomograms (CTs) of the spleen are frequently performed for estimating spleen size and anatomy, but sometimes raise concern over radiographic splenic masses. We performed a retrospective analysis of splenectomized PMF patients to determine the predictive value of CT in these patients.METHODS: Splenectomized patients, with confirmed PMF (and POST ET/PV MF), with an available pre-operative CT scan were included. Pre-operative CT scans were reviewed in a blinded fashion by a radiologist (B.B.), and histopathology was concurrently reviewed in a blinded fashion by a hematopathologist (C.Y.L.), with attention for radiographic evidence of splenic masses, splenic infarction and hemorrhage, evidence of extra-splenic masses. Additionally splenic volume was calculated by CT through an algorithm using maximal splenic length, width, and slice size (prorated ellipsoid where volume = (30+.58(XxYxZ)). Results from each review were compared and analyzed against clinical outcomes and documented splenic mass.RESULTS: Thirty-eight patients had concurrent CT and splenic pathology available underwent splenectomy for myelofibrosis (20 PMF; median age at diagnosis 64.6 years (range (46–79), 52% males). Splenic volume estimations by CT correlated well with splenic mass measurements. Splenic volume estimation by CT was 2365 CC (range 736–11355 CC), compared with a measured median splenic mass of 2000 mg (range 730–11750 mg) (bivariate analysis p<0.001). Splenic lesions were identified in a total of 33 patients (87%), 10 only by histopathology (30%), 3 only by CT (9%), and 20 by both (61%). Histopathologically 15 patients had localized hemorrhage, 13 had splenic infractions, and 8 had nodular foci of extramedullary hematopoiesis. Only 2 patients had evidence of an alternative malignancy (concurrent chronic lymphocytic leukemia (CLL, n =1) or systemic mast cell disease (n = 1). CT was very sensitive for detecting focal low density lesions (LDLs), which are roughly spherical regions of decreased contrast enhancement in the spleen, and detected the majority of macroscopic lesions. The presence of splenic infarctions histologically was associated with decreased post splenectomy survival (p=0.02; median 7.2 months vs. 15.0 months), however the sensitive (but not specific) presence of LDL lesions by CT did not have prognostic significance. The CT appearance of splenic hemorrhage was nonspecific, and since these areas of parenchymal hemorrhage were likely subacute/chronic, they could not be reliably distinguished from other LDLs.CONCLUSIONS: Pre-operative CT in patients whom undergo palliative splenectomy for myelofibrosis is a sensitive tool for determining the presence of small splenic lesions (hemorrhage, infarction and EMH). Additionally splenic volume estimation by CT, correlates well with measured splenic mass and may assist in operative planning. Splenic lesions in PMF (post ET/PV MF) by CT rarely represented an alternative malignant process, and should likely not be the sole indication for splenectomy. Splenic infarctions were associated with decreased survival after splenectomy, however CT is not always able to distinguish these lesions from EMH and hemorrhage.

Asymmetrical or heterogeneous enhancement of the internal jugular veins in contrast-enhanced CT of the head and neck.

With faster CT scanners, asymmetric/heterogeneous enhancement (ASHE) of the internal jugular veins (IJVs) is frequently encountered in the absence of pathology. We investigated the frequency, side, pattern and significance of ASHE in 200 patients with various head and neck lesions. Non-ionic contrast medium (300 mgI/ml) was infused into a forearm vein (right, n = 100); left, n = 100). Forty seconds after contrast medium injection, contiguous 5-mm-thick sections were obtained craniocaudally from the skull base to the aortic arch. CT machines with two different scanning cycle times (3 s, n = 100; 2 s, n = 100) were used. ASHE of the IJVs was observed in 51 patients (25.5%); the patient group receiving a right-sided injection with a 2-s scan cycle machine, showing a higher frequency (44%). ASHE was divided into four patterns: homogeneous low density, focal low density, heterogenous opacification and fluid-fluid level formation. ASHE was frequently observed in routine contrast-enhanced CT of the head and neck. Frequency of ASHE increased when the scanning cycle was shorter. We should be aware of this phenomenon to avoid its misinterpretation as venous thrombosis or other pathology.

Brain oedema in patients with intracranial meningioma. Correlation between clinical, radiological, and histological factors and the presence and intensity of oedema.

The authors analysed the correlation between different clinical, radiological, and pathological variables and the presence and intensity of brain oedema associated to intracranial meningioma in 400 consecutive patients studied by computerized tomography (CT). The following factors did not show significant correlation with brain oedema development: the age and sex of the patient, the occurrence of focal deficits, the presence of skull changes (endostosis, exostosis, osteolysis), the occurrence of tumour calcification, the density of the tumour on plain CT scan, the presence of a cystic component, the pathological subtype of meningioma (both conventional and non-conventional), and the presence of histological features of tumour aggressiveness, such as an increased vascularization, high cellularity, high mitotic index, pleomorphism, necrosis, and brain infiltration. Factors showing a statistically significant correlation with the presence and intensity of brain oedema at the bivariate analysis were: the presence of symptoms (p < 0.001), the duration of the clinical history (p < 0.05), the location and size of the tumour (p < 0.001), the type (heterogeneous vs homogeneous), and intensity of tumour contrast enhancement (p < 0.001), the presence of irregular tumour margins (p < 0.001), and the existence of focal low density intratumoural areas (p < 0.001). The multivariate analysis using only clinical parameters showed that the group of variables with the highest power for predicting the presence of brain oedema (concordance level of 76.8%) included: the presence of symptoms, the occurrence of seizures (focal or generalized), the presence of an intracranial hypertension syndrome, and the age of the patient. The multivariate analysis using only anatomico-radiological parameters showed that the model which included the size of the tumour, the intensity of contrast enhancement, the tumour margins, and meningioma location, predicted the presence of brain oedema in 80.8% of the cases. Though the results of the present study do not definitively support any of the major physiopathological theories proposed to explain brain oedema formation in patients with intracranial meningioma, some findings could favour the so-called hydrodynamic theory.

Cerebrotendinous xanthomatosis: cranial CT and MRI studies in eight patients.

We report the findings on cranial computed tomography (CT) and magnetic resonance imaging (MRI) and their correlation with the clinical manifestations, disease severity and biochemical abnormalities in eight patients with cerebrotendinous xanthomatosis. CT revealed cerebral atrophy in seven cases, cerebellar atrophy in four and focal low density lesions in the cerebral white matter in two. T2-weighted MRI showed high signal lesions in the cerebral white matter, focal in four cases and diffuse in one, and in the globus pallidus in three patients, two of whom also had lesions in the cerebellar white matter. While severely affected patients showed variable CT and MRI abnormalities, our cases did not show the dramatic findings expected from the neurological manifestations. Diffuse lesions in the cerebral and cerebellar white matter have been emphasized in previous reports, but in our study the focal lesions in the cerebral white matter were also present; the globus pallidus was frequently involved.

Cranial computed tomographic findings in children with newly diagnosed acute lymphoblastic leukemia: a prospective follow-up study during treatment.

Cranial computed tomography (CT) was performed on 40 consecutive children with newly diagnosed acute lymphoblastic leukemia (ALL) on admission before any chemotherapy, 5 months after CNS therapy (n = 39) and after 2 to 3 years of therapy (n = 31). Changes related to leukemia were found in only 10% of the patients at the time of diagnosis (4/40). These initial changes, two intracranial hemorrhages, one dural thickening and one contrast enhancement, all disappeared during therapy. The findings which persisted unchanged in the next two CT scans were thought to be normal variations or caused by earlier disorders. CNS therapy consisted of intrathecally and intravenously administered methotrexate in 20 standard risk (SR) patients and cranial irradiation in addition to chemotherapy in 19 intermediate risk (IR) or high risk (HR) patients. Four SR patients developed changes during therapy. Three had enlarged cerebrospinal fluid (CSF) spaces and one developed a focal low density area suggesting disturbances in brain blood circulation and also experienced disturbances in level of consciousness. Of the 19 IR or HR patients, eight developed changes related to the therapy, including four with white matter hypodensity areas, of whom three also had enlarged CSF spaces, and four others who developed enlarged CSF spaces. The medians of the widths of the cortical sulci (P less than .001), insular cisterns (P less than .01), third ventricles (P less than .01), and frontal horns (P less than .05), and also of Evans' ratios (P less than .05) increased significantly after CNS therapy as compared with the findings at diagnosis in the patients who had received cranial irradiation. Most of these changes persisted during the follow-up. We conclude that the clinical value of CT scanning during therapy for ALL is restricted to patients with neurological symptoms or those who have undergone CNS irradiation.

Normal brain response after interstitial microwave hyperthermia

The effects of interstitial hyperthermia were assessed in the normal brain after a single 30 min treatment using 2450 MHz microwaves. A single helical coil microwave antenna was inserted into the frontal white matter and reference temperatures of 40, 41, 42, 43 and 44 degrees C maintained for 30 min along a temperature sensing probe 5 mm away and parallel to the antenna. The extent of hyperthermia damage was quantified weekly for 6 weeks using computed tomography (CT), and changes in regional cerebral blood flow (rCBF), tissue vascularity and mean transit time were determined using ultrafast CT. Qualitative histopathological analysis was carried out on tissues at various times after heating. Heat lesions were radiographically characterized by rapid development and resolution and consisted of an area of focal low density surrounded by a ring of contrast enhancement. Histologically, the focus of low density corresponded to regions of tissue necrosis, whereas the ring enhancement showed local reactive changes, including endothelial cell proliferation and infiltration with macrophages. Tissue necrosis occurred at temperatures greater than 43.9 +/- 1.5 degrees C (mean +/- standard deviation), and volumes of necrosis and ring enhancement were at a maximum 1 week following treatment. Relative to the contralateral, unheated hemisphere, rCBF in the heated brain appeared to be reduced for the first 3 weeks after treatment but approached normal by week 4. The mean transit time of blood was increased for weeks 1-3 compared to the untreated hemisphere, and tissue vascularity reached a maximum, 3 weeks after treatment. The rapid CT changes together with ultrafast CT and histopathological findings suggest that focal heat lesions in the brain stimulate a significant and rapid vascular response.

A mitochondrial encephalomyopathy with cardiomyopathy: A case revealing a defect of complex I in the respiratory chain

We describe a 16-year-old Japanese girl with a mitochondrial encephalomyopathy who presented with progressive dementia, limb weakness and atrophy, episodic vomiting, generalized convulsions, myoclonic seizures, and hypertrophic cardiomyopathy. CT scan revealed transient focal low density areas in her occipital and parietal lobes, and cerebellar atrophy. The clinical features were consistent with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS). Microscopically, most of muscle fibers in the skeletal muscles and heart were occupied by markedly increased mitochondria. Polarographic studies on mitochondria isolated from postmortem heart muscle showed severe impairment of oxidation of NADH-linked substrates in contrast to normal succinate oxidation. The rotenone-sensitive NADH-coenzyme Q reductase activity was markedly decreased in heart, skeletal muscle and liver mitochondria. The biochemical investigations have led to the identification of a defect of complex I in the respiratory chain. Reported cases of a defect of complex I have revealed pure myopathy, encephalopathy or encephalomyopathy. The reason for a varied clinical expression of a single defect remains to be clarified.

Pseudometastases secondary to film static artifact

Low density areas in the liver on computed tomography (CT) may be produced by cysts, abscesses, or tumors. A case is reported in which film static resulted in multiple focal low density areas in the liver in a patient with lymphoma. This potential pitfall in CT interpretation can be avoided by taking proper measures to avoid film artifacts and by reviewing all cases on the cathode ray tube (CRT) display as well as the hard copy film.

Acute hemiplegia with lacunar infarct after varicella infection in childhood

We report 4 cases of acute hemiplegia and a small low-density lesion on computerized tomography (CT) after varicella infection. In 3 of them, CT in the acute hemiplegic stage, and later, reveals the development of lacunar infarct around the internal capsule. Focal low density may be caused by occlusive vascular lesions of the penetrating arteries. Varicella infection may play an important role as one of the causes of acute hemiplegia in childhood producing lacunar infarct, as well as delayed hemiplegia, reported previously in herpes zoster ophthalmicus.

Computed tomography in mitochondrial cytopathy.

The clinical and computed tomographic (CT) findings in 11 proven cases of mitochondrial cytopathy (mitochondrial myopathy, Kearns Sayre syndrome, ophthalmoplegia plus) were studied. The CT changes included focal low density lesions in the basal ganglia and white matter and atrophy which could be slight or diffuse and severe. Calcification has been described in the basal ganglia, but did not occur in our series. Serial CT showed progression of the abnormalities. The differential diagnosis is discussed.

Role of computerized transverse axial tomography on stereotactic surgery of the diencephalon. A preliminary report of 67 cases.

67 cases of various functional disorders of the diencephalon were examined by EMI scanner. The patients were composed of 38 cases of parkinsonism, 7 cases of thalamic syndrome, 6 cases of choreoathetoid movement, 2 cases of dystonia, 11 cases of involuntary movement of unknown etiology and 1 case of torticollis, tic, and ballismus, respectively. In parkinsonism, 79% showed diffuse cerebral atrophy, 5% had focal low density in the substantia nigra and the thalamus, whereas 16% remained normal. Pre- and postoperative assessment with CT scan was briefly discussed with reference to stereotactic surgery of the diencephalon.