Combined dual energy and iterative metal artefact reduction for PET/CT in head and neck cancer.

Metal artefacts in PET/CT images hamper diagnostic accuracy in head and neck cancer (HNC). The aim of this study is to characterise the clinical effects of metal artefacts on PET/CT in HNC and to inform decision-making concerning implementation of MAR techniques. We study a combined dual energy CT and inpainting-based metal artefact reduction (DECT-I-MAR) technique for PET/CT in three settings: (A) A dental phantom with a removable amalgam-filled tooth to evaluate the PET error in comparison to a known reference. (B) PET-positive patients with metallic implants to demonstrate the relationship between CT metal artefacts and PET error. (C) Metabolic tumour volumes delineated in PET-positive patients with metal implants to evaluate the clinical impact. In (A) DECT-I-MAR reduced the PET error significantly. In (B) we demonstrate an increasing PET error with increasing CT artefact severity in patients. In (C) it is shown that the presence of artefacts in the same axial slices as the tumour significantly decreases biomarker stability and increase delineation variability. This work shows the practical feasibility of DECT-I-MAR-based PET/CT imaging, and indicates a positive clinical impact of using the technique routinely for HNC patients. The impact of CT artefacts on PET is considerable, especially in workflows where quantitative PET biomarkers and tumour volumes are used. In such cases, and for patients with tumours in proximity of metals, we recommend that a MAR technique for PET/CT is employed.

Combined PET/MRI: Multi-modality Multi-parametric Imaging Is Here: Summary Report of the 4th International Workshop on PET/MR Imaging; February 23-27, 2015, Tübingen, Germany.

This paper summarises key themes and discussions from the 4th international workshop dedicated to the advancement of the technical, scientific and clinical applications of combined positron emission tomography (PET)/magnetic resonance imaging (MRI) systems that was held in Tübingen, Germany, from February 23 to 27, 2015. Specifically, we summarise the three days of invited presentations from active researchers in this and associated fields augmented by round table discussions and dialogue boards with specific topics. These include the use of PET/MRI in cardiovascular disease, paediatrics, oncology, neurology and multi-parametric imaging, the latter of which was suggested as a key promoting factor for the wider adoption of integrated PET/MRI. Discussions throughout the workshop and a poll taken on the final day demonstrated that attendees felt more strongly that PET/MRI has further advanced in both technical versatility and acceptance by clinical and research-driven users from the status quo of last year. Still, with only minimal evidence of progress made in exploiting the true complementary nature of the PET and MRI-based information, PET/MRI is still yet to achieve its potential. In that regard, the conclusion of last year's meeting "the real work has just started" still holds true.

Whole-body PET/MRI: the effect of bone attenuation during MR-based attenuation correction in oncology imaging.

PURPOSE: In combined PET/MRI standard PET attenuation correction (AC) is based on tissue segmentation following dedicated MR sequencing and, typically, bone tissue is not represented. We evaluate PET quantification in whole-body (WB)-PET/MRI following MR-AC without considering bone attenuation and then investigate different strategies to account for bone tissue in clinical PET/MR imaging. To this purpose, bone tissue representation was extracted from separate CT images, and different bone representations were simulated from hypothetically derived MR-based bone classifications. METHODS: Twenty oncology patients referred for a PET/CT were injected with either [18F]-FDG or [18F]-NaF and imaged on PET/CT (Biograph TruePoint/mCT, Siemens) and PET/MRI (mMR, Siemens) following a standard single-injection, dual-imaging clinical WB-protocol. Routine MR-AC was based on in-/opposed-phase MR imaging (orgMR-AC). PET(/MRI) images were reconstructed (AW-OSEM, 3 iterations, 21 subsets, 4mm Gaussian) following routine MR-AC and MR-AC based on four modified attenuation maps. These modified attenuation maps were created for each patient by non-linear co-registration of the CT images to the orgMR-AC images, and adding CT bone mask values representing cortical bone: 1200HU (cortCT), spongiosa bone: 350HU (spongCT), average CT value (meanCT) and original CT values (orgCT). Relative difference images of the PET following AC using the modified attenuation maps were compared. SUVmean was calculated in anatomical reference regions and for PET-positive lesions. RESULTS: The relative differences in SUVmean across patients following orgMR-AC and orgCT in soft tissue lesions and in bone lesions were similar (range: 0.0% to -22.5%), with an average underestimation of SUVmean of 7.2% and 10.0%, respectively when using orgMR-AC. In bone lesions, spongCT values were closest to orgCT (median bias of 1.3%, range: -9.0% to 13.5%) while the overestimation of SUVmean with respect to orgCT was highest for cortCT (40.8%, range: 1.5% to 110.8%). For soft tissue lesions the bias was highest using cortCT (13.4%, range: -2.3% to 17.3%) and lowest for spongCT (-2.2%, range: 0.0% to -13.7%). CONCLUSIONS: In PET/MR imaging using standard MR-AC PET uptake values in soft lesions and bone lesions are underestimated by about 10%. In individual patients this bias can be as high as 22%, which is significant during clinical follow-up exams. If bone segmentation is available, then assigning a fixed attenuation value of spongious bone to all bone structures appears reasonable and results in only a minor bias of 5%, or less in uptake values of soft tissue and bone lesions.

Inverted papilloma: incidence and late results of surgical treatment.

The 452,000 inhabitants of the County of Funen are considered to constitute a representative section of the population of Denmark. The county is geographically well-defined, surrounded by sea. Specimens from the two Departments of Pathology in the county have been histologically reviewed. Our incidence material consists of 96 patients suffering from inverted papillomas, during a 14-year period, which corresponds to 1.5 cases per 100,000 inhabitants per year. During the same 14-year period, 67 patients have been operated upon at the ENT Department of Odense University Hospital. In 1992, a clinical re-examination was performed regarding late surgical results. Fourteen per cent (9/67) have developed recurrences from 6 to 56 months after the first operation. No major late surgical complications have been observed. It is our experience that lesions limited to the nasal septum and minor lesions on the lateral nasal wall can be treated primarily by an intranasal procedure. Large lesions on the lateral wall with best results have been treated by lateral rhinotomy.

Cloning and expression in insect cells of two pancreatic lipases and a procolipase from Myocastor coypus.

The physiological role of pancreatic lipases has traditionally been assigned solely to triacylglyceride metabolism, while the digestion of phospholipids requires the presence of the pancreatic phospholipase A2, a 14-kDa enzyme unrelated to pancreatic lipases. However, in the guinea pig, it was observed that the pancreatic phospholipase A2 was absent and that a guinea pig pancreatic-lipase-related protein 2 (GPL-RP2) was responsible for phospholipase activity, in contrast to the situation observed in other mammalian species. As the guinea pig is a member of the hystricomorph rodents, it was of interest to investigate if other species within this evolutionary suborder display similar characteristics. The coypu (Myocastor coypus) also a member of the hystricomorph rodents, was chosen for further investigations. The cDNAs encoding two pancreatic lipases and a procolipase from the coypu were cloned, expressed and characterized. One lipase, CoPL-RP2, was identified as belonging to the RP2 subfamily, while the second, CoPL, was found to belong to the classical pancreatic lipase subfamily. Enzymic characterization and sequence data suggest a role for coypu colipase as a specific cofactor for CoPL, while this coypu colipase cannot be an important cofactor for CoPL-RP2 in vivo. Also, the new lipase cDNA sequences were used in a phylogentic analysis to reinvestigate the taxonomical position of the hystricomorph rodents (e.g. coypu and guinea pig) with respect to the myomorph rodents (e.g. rat and mouse).

Xanthogranulomatous cholecystitis. A clinicopathological study of 20 cases and review of the literature.

Xanthogranulomatous cholecystitis (XGC) is a focal or diffuse destructive inflammatory process of the gall bladder, characterized macroscopically by yellowish tumour-like masses in the wall of the gall bladder. Microscopically, it is characterized in the early stages by a large number of foamy histiocytes and acute inflammatory cells. Later stages demonstrate increasing fibrosis. The gall bladder from 20 of 352 consecutive patients subjected to cholecystectomy showed XGC. Gall stones were found in the gall bladder of all 20 patients and in the ductus choledochus in 3 cases. Perforation of the gall bladder was observed at operation in six cases; in one case there was also a fistula to the colon. A perivesical abscess was found in five other cases. Adhesions to the surrounding structures were seen in a total of 16 cases. Pathogenetically, XGC is probably due to an interplay between obstruction of the gall flow, infection with subsequent inflammation, and leakage of gall fluid to the tissue, where histiocytes accumulate and phagocytize the bile pigment, haemosiderin and cholesterol, resulting in the formation of xanthoma cells. The correct diagnosis of XGC is important for several reasons, first and foremost due to the high frequency of complications, but not least because the condition may give rise peroperatively to the suspicion of malignancy. The new laparoscopic method for cholecystectomies further stresses the necessity of correct preoperative diagnosis of complicating disease.

The reliability of staging and grading of bladder tumours. Impact of misinformation on the pathologist's diagnosis.

The influence of misinformation on the reliability of the histopathological classification of bladder tumours was analysed. Four consultant pathologists assessed 40 biopsy specimens of bladder tumours staging invasion and grading the specimens according to the Bergkvist classification. A random sample of 20 specimens was accompanied by systematically distorted information ("bias"-unknown to the pathologists) about previous histological grading of the patient (bias group); the other 20 specimens were used as control group (non bias group). After 6 months a second round with the same specimens was arranged to assess the influence of bias on the intraobserver variation. Using kappa (kappa) statistics the chance corrected interobserver agreement rate was poor both in staging of invasion and grading according to the Bergkvist classification (kappa < 0.50). The kappa values in the intraobserver study ranged from poor to excellent with a tendency towards lower kappa when the observer had been biased. The kappa values in the assessment of malignancy were acceptable to excellent. False information did not affect the pathologists' diagnosis significantly.

[Prognostic factors in pigmented villonodular synovitis]. / Prognostiske faktorer ved pigmenteret villonodulaer synovitis.

By means of the diagnostic register, all of the patients in the County of Funn with the diagnosis pigmented villonodular synovitis (PVS) during the years 1973 to 1987 were localized. Out of 22 patients, 19 were followed-up clinically and radiologically. Fifteen patients had PVS in a knee, 63% were women. The diagnosis was established late. Repeated punctures of the knee with dark aspirate without relevant trauma should raise the suspicion of PVS. The clinical course of the disease could not be related to the radiographic findings or the histology but depended rather on the localization. In some patients, PVS ran a more aggressive course and arthroses were observed electively in patients treated early. The prognosis in cases diagnosed early was not better but, as treatment yielded considerable relief of symptoms, early treatment was considered to be of value. This consists of local resection of the nodular PVS elements and as radical synovectomy as possible in the diffuse cases. Treatment of recurrences should depend on the symptoms and the degree of possible arthrosis. One patient who had had three recurrences received irradiation with good results. Restricted joint mobility after synovectomy is treated effectively with brisement.

Malignant melanoma. Changing trends in factors influencing metastasis-free survival from 1964 to 1982.

Seven hundred fourteen patients with cutaneous melanoma in clinical Stage I treated between 1964 and 1982 were included in this study. In an analysis of metastasis-free survival, thickness of the tumor, ulceration, gender, epithelioid cells as predominant cells in the tumor, and localization of the tumor were found to be independent prognostic factors. In a time trends analysis, the distributions of three of the prognostic factors (thickness of the tumor, ulceration, and inflammatory cell infiltrate) were found to shift during the last decade in the direction of improved prognosis, indicating that tumors are detected earlier than before. The distributions of two other factors (cell type and location of the tumors) shifted in the direction of deteriorated prognosis, suggesting partly that the biologic nature of the disease may have changed and partly that other behavioral factors may have played a role.

[Urine cytology as a supplement to cystoscopy and biopsy in the control of bladder tumors]. / Urincytologi som supplement til cystoskopi og biopsi ved kontrol af blaeretumorer.

Throughout the years several investigations have either recommended or discredited exfoliative urine cytology because of high incidence of false negative or false positive results. Most authors agree that high grade bladder tumors are diagnosed with fairly high certainty (80-87%) by using exfoliative urine cytology whereas the value of urine cytology of low grade bladder tumors is uncertain. This investigation, including 200 patients who came for cystoscopic control of bladder tumors, revealed 87% accordance between cystoscopic biopsy and exfoliative urine cytology of high grade tumors while there were 47% false negative and no false positive of low grade tumors. On this background, it must be concluded that exfoliative urine cytology is an important investigation in diagnosing and controlling patients with bladder tumors, but the method can not always stand alone.

Synovial haemangiopericytoma of the knee joint.

We report a case of haemangiopericytoma occurring intra-articularly in the synovium of the knee joint. This is a rare tumour which, as far as is known to the authors, has not previously been described in a subsynovial site.

Amyloid deposits in surgically removed articular and periarticular tissue.

In tissue from 13 of 30 patients subjected to meniscectomy, amyloid degeneration was found to varying extent along the surface of the meniscus. Tissue from 30 synovectomies, 30 bursectomies and 30 ganglia showed amyloid deposits in four, six and eight cases, respectively. Amyloid was found significantly more frequently in older patients, but there was no sex difference and no relation to duration of the symptoms or to other histological changes in the tissue. Micro-deposits of amyloid in joint tissue and tissue neighbouring joints are a frequent finding, especially in elderly persons, but the clinical significance of this finding is not clear.

The influence of resection margin on prognosis in clinical stage I malignant melanoma of the lower leg.

The incidence of local recurrence and cumulative survival rate were compared for two groups of patients with stage I malignant melanoma of the lower leg. Group 1 included 119 patients treated from 1964 to 1978 with a wide local excision extending to the ankle. Group 2 included 58 patients treated from 1978 to 1981 with a 5 cm incision margin in all directions. Lesions within both groups were comparable based on measurements of tumor thickness. However, level of invasion indicated significantly more advanced lesions in the first group. Risk of local recurrence was related to thickness and ulceration. There were no statistically significant differences in frequency of local recurrences or cumulative survival rates between the two groups.

Xanthogranulomatous inflammation of the female genital tract.

We describe three cases of xanthogranulomatous inflammation in the female genital tract--one affecting endometrium, tube and ovary, one affecting tube, ovary and parametrium and one confined to the endometrium. To date, xanthogranulomatous inflammation in the female genital tract has been reported in a total of 19 cases including the present three. The inflammation most often affects the endometrium but involvement of the vagina, cervix, fallopian tube and ovary may also occur.

A case of aggressive pigmented villonodular synovitis.

An unusual case of pigmented villonodular synovitis affecting a knee joint is described. Shortly after synovectomy, extensive bone and ligament destructions occurred and made conservative surgery impossible.

Hepatocellular calcification.

Autopsy of a twenty year old girl dying from complications of renal and cardiac failure demonstrated severe hepatocellular calcification, a rare finding. The pathogenesis is thought to be a combination of dystrophic calcification caused by severe centrilobular necrosis and metastatic calcification due to secondary hyperparathyroidism.

Crushed cartilage in nasal reconstruction.

Experience when using crushed cartilage for restoration of the dorsal nasal contour is presented. The septal cartilage is used as fresh autogenous grafts and as preserved septal cartilage. Implantation of autogenous grafts is preferable. Bank cartilage, however, has the advantage of being easily available and of causing very little reaction in the host organism. Normally, it is absorbed very slowly and replaced by connective tissue, which retains most of the bulk and shape of the implant. The crushed material is pushed in over the undermined nasal dorsum by means of a syringe connected to a plastic tube. When the piston of the loaded syringe is depressed, the cartilage is injected and the crushed cartilage can be moulded under the skin and the shape maintained by a tight dressing. The cartilage serves as a padding, which covers bony defects, smooths out the irregularities of the bone and avoids the open roof syndrome as well as retracted scar formation between skin and bone.

Amyloid deposits in the knee joint at autopsy.

Joint capsule, meniscus, and cartilage from the patella and medial femoral condyle from 30 non-selected autopsies have been investigated for amyloid deposits with light and electron microscopy. Both right and left knee joints from 28 of the 30 autopsy specimens contained amyloid deposits (93%). The amyloid characteristically showed green dichroism in polarised light after staining with alkaline Congo red. The ultrastructural features were also characteristic of amyloid. Amyloid in capsule tissue was found in a subsynovial location, as well as deeper in the capsule tissue, while in the cartilage amyloid was localised along the surface. The meniscus tissue, in particular, contained heavy deposits of amyloid--mainly along the inner margin. Osteoarthritic changes, with fibrillation of the cartilage, were significantly related to amyloid deposition. No pathogenetic correlation between the osteoarthritic changes and amyloid deposition could be shown in the present investigation.

Parathyroid carcinoma: a case with recurrence treated with extensive vascular surgery to the neck.

Parathyroid carcinoma is a slow growing tumor, and the patients most often die from complications to the hypercalcemia. Therefore, any attempt should be made to remove local recurrence and metastasis surgically, as medical treatment is disappointing. A case treated with extensive vascular surgery to the neck is reported.

Amyloid in intervertebral discs: a histopathological investigation of surgical material from 100 consecutive operations on herniated discs.

Material from 100 consecutive operations on herniated discs has been investigated for amyloid. Various degrees of amyloid degeneration were found in disc tissue from 41 patients. Material from patients over 50 years old showed significantly more amyloid than that from younger patients; there was no sex difference. Eighteen patients had previously been operated on for herniated discs; seven of these (39%) had pyrophosphate deposits in their disc tissue, often in close topographical relation to amyloid. 26% of the patients had calcium phosphate deposits and 29% had slight inflammation--both without relation to amyloid. No pathogenetic correlation between amyloid degeneration and herniation of intervertebral disc tissue could be shown.