High-resolution MRI of mummified tissues using advanced short-T2 methodology and hardware.

PURPOSE: Evolutionary medicine aims to study disease development from a long-term perspective, and through the analysis of mummified tissue, timescales of several thousand years are unlocked. Due to the status of mummies as ancient relics, noninvasive techniques are preferable, and, currently, CT imaging is the most widespread method. However, CT images lack soft-tissue contrast, making complementary MRI data desirable. Unfortunately, the dehydrated nature and short T2 times of mummified tissues render them practically invisible to standard MRI techniques. Specialized short-T2 approaches have therefore been used, but currently suffer severe resolution limitations. The purpose of the present study is to improve resolution in MRI of mummified tissues. METHODS: The zero-TE-based hybrid filling technique, together with a high-performance magnetic field gradient, was used to image three ancient Egyptian mummified human body parts: a hand, a foot, and a head. A similar pairing has already been shown to increase resolution and image quality in MRI of short-T2 tissues. RESULTS: MRI images of yet unparalleled image quality were obtained for all samples, reaching isotropic resolutions of 0.6 mm and SNR values above 100. The same general features as present in CT images were depicted but with different contrast, particularly for regions containing embalming substances. CONCLUSION: Mummy MRI is a potentially valuable tool for (paleo)pathological studies, as well as for investigations into ancient mummification processes. The results presented here show sufficient improvement in the depiction of mummified tissues to clear new paths for the exploration of this field.

CT-based and morphological comparison of glenoid inclination and version angles and mineralisation distribution in human body donors.

BACKGROUND: For optimal prosthetic anchoring in omarthritis surgery, a differentiated knowledge on the mineralisation distribution of the glenoid is important. However, database on the mineralisation of diseased joints and potential relations with glenoid angles is limited. METHODS: Shoulder specimens from ten female and nine male body donors with an average age of 81.5 years were investigated. Using 3D-CT-multiplanar reconstruction, glenoid inclination and retroversion angles were measured, and osteoarthritis signs graded. Computed Tomography-Osteoabsorptiometry (CT-OAM) is an established method to determine the subchondral bone plate mineralisation, which has been demonstrated to serve as marker for the long-term loading history of joints. Based on mineralisation distribution mappings of healthy shoulder specimens, physiological and different CT-OAM patterns were compared with glenoid angles. RESULTS: Osteoarthritis grades were 0-I in 52.6% of the 3D-CT-scans, grades II-III in 34.3%, and grade IV in 13.2%, with in females twice as frequently (45%) higher grades (III, IV) than in males (22%, III). The average inclination angle was 8.4°. In glenoids with inclination ≤10°, mineralisation was predominantly centrally distributed and tended to shift more cranially when the inclination raised to > 10°. The average retroversion angle was - 5.2°. A dorsally enhanced mineralisation distribution was found in glenoids with versions from - 15.9° to + 1.7°. A predominantly centrally distributed mineralisation was accompanied by a narrower range of retroversion angles between - 10° to - 0.4°. CONCLUSIONS: This study is one of the first to combine CT-based analyses of glenoid angles and mineralisation distribution in an elderly population. The data set is limited to 19 individuals, however, indicates that superior inclination between 0° and 10°-15°, and dorsal version ranging between - 9° to - 3° may be predominantly associated with anterior and central mineralisation patterns previously classified as physiological for the shoulder joint. The current basic research findings may serve as basic data set for future studies addressing the glenoid geometry for treatment planning in omarthritis.

Glenoid morphology in light of anatomical and reverse total shoulder arthroplasty: a dissection- and 3D-CT-based study in male and female body donors.

BACKGROUND: Placement of the glenoid baseplate is of paramount importance for the outcome of anatomical and reverse total shoulder arthroplasty. However, the database around glenoid size is poor, particularly regarding small scapulae, for example, in women and smaller individuals, and is derived from different methodological approaches. In this multimodality cadaver study, we systematically examined the glenoid using morphological and 3D-CT measurements. METHODS: Measurements of the glenoid and drill hole tunnel length for superior baseplate screw placement were recorded to define size of the glenoid and the distance to the scapular notch on cadaveric specimens. Glenoid angles were determined on both, 3D-CT-scans of the thoraxes using the Friedman method and on subsequently isolated scapulae from 18 male and female donors (average 84 years, range 60-98 years). RESULTS: Mean glenoid height was 36.6 mm ± 3.6, and width 27.8 mm ± 3.1 with a significant sex dimorphism (p ≤ 0.001): in males, glenoid height 39.5 mm ± 3.5, and width 30.3 mm ± 3.3, and in females, glenoid height 34.8 mm ± 2.2, and width 26.2 mm ± 1.6. The average distance from the superior screw entry to its exit in the scapular notch measured by calliper was 27.2 mm ± 6.0 with a sex difference: in males, 29.4 mm ± 5.7, and in females, 25.8 mm ± 5.9 mm with a minimum recorded distance of 15 mm. Measured by CT, the mean inclination angle for male and female donors combined was 13.0° ± 7.0, and the ante-/retroversion angle -1.0° ± 4.0°. CONCLUSION: This study is one of the first to combine dissection, including drill holes, with anatomical measurements and radiological data. In some women and smaller individuals, smaller baseplates should be selected. The published safe zone of 20 mm is generally feasible for superior screw placement, however, in small patients this distance may be substantially shorter than expected and start as of 13 and 15 mm, respectively. No correlation between glenoid height or width with the length of our drilling canal towards the scapular notch was found. Preoperative CT-based treatment planning to determine version and inclination angles is recommended.

Comparison of ultrashort echo time sequences for MRI of an ancient mummified human hand.

PURPOSE: To compare the three different short-echo time (TE) pulse sequences ultrashort echo time (UTE), point-wise encoding time reduction with radial acquisition (PETRA), and single point imaging (SPI) for MRI of ancient remains. METHODS: MRI of mummies is challenging due to the extremely low water content and the very short transverse relaxation times T2 *. To overcome the signal loss associated with the short T2 *, three pulse sequences with very short TEs were compared. MR images of an ancient mummified human hand were acquired at field strengths of 1.5 Tesla (T) and 3T using home-made solenoid Tx/Rx radiofrequency (RF) coils. RESULTS: In all MR images, tissues could be differentiated and anatomical structures such as bones and tendons were clearly identified. Skin with embalming resin was hyperintense in MRI, whereas it appeared iso-intense in computed tomography. PETRA has the highest signal to noise ratio. With UTE, short scan times and a homogeneous RF excitation can be achieved, and blurring is less pronounced than with PETRA. SPI shows no blurring artifacts; however, it requires long scan times. CONCLUSION: This work provided an initial analysis for the optimization of imaging protocols for paleoradiology studies with MRI, and, ultimately, for MRI of tissue with extremely short T2 *.

Risk to fragmented DNA in dry, wet, and frozen states from computed tomography: a comparative theoretical study.

Computed tomography represents the gold standard in forensic and palaeopathological diagnosis. However, the X-rays used may affect the DNA quality through fragmentation and loss of genetic information. Previous work showed that the effects of ionizing radiation on dry DNA are non-significant with P < 10(-8), which cannot be detected by means of polymerase chain reaction methods. In the present paper, complete analytical model that characterizes radiation effects on fragmented DNA in dry, wet, and frozen states is described. Simulation of radiation tracks in water phantom cells was performed using the Geant4-DNA toolkit. Cell hits by electrons with energies between 5 and 20 keV were simulated, and the formation of radiolytic products was assessed at a temperature of 298 K. The diffusion coefficient and the mean square displacement of reactive species were calculated by Stokes-Einstein-Smoluchowski relations at 273 K. Finally, DNA fragment damage was estimated using the density distribution of fragments calculated from atomic force microscopy images. The lowest probability of radiation-induced DNA damage was observed for dry state, with a range from 2.5 × 10(-9) to 7.8 × 10(-12) at 298 K, followed by that for frozen state, with a range from 0.9 to 4 × 10(-7) at 273 K. The highest probability of radiation-induced DNA damage was demonstrated for fragmented DNA in wet state with a range from 2 to 9 × 10(-7) at 298 K. These results significantly improve the interpretation of CT imaging in future studies in forensic and palaeopathological science.

New perspectives on evolutionary medicine: the relevance of microevolution for human health and disease.

Evolutionary medicine (EM) is a growing field focusing on the evolutionary basis of human diseases and their changes through time. To date, the majority of EM studies have used pure theories of hominin macroevolution to explain the present-day state of human health. Here, we propose a different approach by addressing more empirical and health-oriented research concerning past, current and future microevolutionary changes of human structure, functions and pathologies. Studying generation-to-generation changes of human morphology that occurred in historical times, and still occur in present-day populations under the forces of evolution, helps to explain medical conditions and warns clinicians that their current practices may influence future humans. Also, analyzing historic tissue specimens such as mummies is crucial in order to address the molecular evolution of pathogens, of the human genome, and their coadaptations.

Scenes from the past: MR imaging versus CT of ancient Peruvian and Egyptian mummified tissues.

Ancient Egyptian and Peruvian mummies are extremely valuable historical remains, and noninvasive methods for their examination are desirable. The current standard of reference for radiologic imaging of mummies is computed tomography (CT), with tissue having a homogeneous appearance on all CT images. It was long believed that ancient mummified tissue could not be studied with magnetic resonance (MR) imaging because of the low water content in mummies. Recently, however, the usefulness of MR imaging in the evaluation of mummified tissue was demonstrated for the first time, with use of a special ultrashort echo time technique. The authors of the present study acquired and analyzed MR imaging and CT data from the left hands of two ancient Egyptian mummies and the head of a third Egyptian mummy (ca 1500-1100 bce), as well as data from an ancient Peruvian mummy (ca 1100 ce). CT was found to provide superior detail of the anatomic structures, mainly because of its higher spatial resolution. The signal intensity of mummified tissue varied greatly on MR images; thus, the quality of these images is not yet comparable to that of clinical MR images, and further research will be needed to determine the full capacity of MR imaging in this setting. Nevertheless, additional information may theoretically be obtained with MR imaging, which should be viewed as complementary to, rather than a replacement for, CT.

Direct action of radiation on mummified cells: modeling of computed tomography by Monte Carlo algorithms.

X-ray imaging is a nondestructive and preferred method in paleopathology to reconstruct the history of ancient diseases. Sophisticated imaging technologies such as computed tomography (CT) have become common for the investigation of skeletal disorders in human remains. Researchers have investigated the impact of ionizing radiation on living cells, but never on ancient cells in dry tissue. The effects of CT exposure on ancient cells have not been examined in the past and may be important for subsequent genetic analysis. To remedy this shortcoming, we developed different Monte Carlo models to simulate X-ray irradiation on ancient cells. Effects of mummification were considered by using two sizes of cells and three different phantom tissues, which enclosed the investigated cell cluster. This cluster was positioned at the isocenter of a CT scanner model, where the cell hit probabilities P(0,1,…, n) were calculated according to the Poisson distribution. To study the impact of the dominant physics process, CT scans for X-ray spectra of 80 and 120 kVp were simulated. Comparison between normal and dry tissue phantoms revealed that the probability of unaffected cells increased by 21 % following cell shrinkage for 80 kVp, while for 120 kVp, a further increase of unaffected cells of 23 % was observed. Consequently, cell shrinkage caused by dehydration decreased the impact of X-ray radiation on mummified cells significantly. Moreover, backscattered electrons in cortical bone protected deeper-lying ancient cells from radiation damage at 80 kVp X-rays.

Confirmation of microevolutionary increase in spina bifida occulta among Swiss birth cohorts.

Previous studies on the prevalence of spina bifida occulta have indicated a microevolutionary increase in its frequency and possible population differences in the prevalence of the condition. We studied the frequencies of closed and open sacral canals at each sacral level among two birth cohorts in Switzerland. Transverse CT scans and multiplanar reconstruction images of sacra of 95 males and 96 females born in 1940-1950 and 99 males and 94 females born in 1970-1980 in Switzerland were reviewed. We found that individuals born later have significantly more open sacral arches at all sacral levels compared to those born 30-40 years earlier. When results were related to previously published data on Australian cohorts, the trend was the same, but Swiss in both cohorts were less likely to have an open section than Australians at all locations apart from S2. This study confirmed a microevolutionary trend in the opening of sacral canal among two different generations in Switzerland and demonstrated a population difference in the prevalence of spina bifida occulta.

Radiological and histological findings in ancient salt mummies from the salt mine of Douzlakh, Iran.

Computed tomography studies and histological analyses were performed on the mummified remains found in the Chehrabad salt mine in northwestern Iran. The ancient salt mummies are dated to the Achaemenid (550-330 BC) and Sassanid (3rd-7th century AD) time period and died in mining incidents. The aim of the study was to describe the radiological and histological findings of several ancient Iranian salt mummies with special interest in pathological and postmortem changes. The mummified remains show multiple traumatic alterations, such as fractures and signs of massive compression. Histological analyses can clearly differentiate soft tissue, however the preservation status is variable. These Iranian salt mummies are a rare example of the ancient Iranian population. The soft tissue and organs are well preserved, however in different degrees due to the varying conditions.

Technical note: Terahertz imaging of ancient mummies and bone.

Ancient mummified soft-tissues are a unique source to study the evolution of disease. Diagnostic imaging of such historic tissues is of foremost interest in paleoanthropology or paleopathology, with conventional x-ray and computed tomography (CT) being the gold-standard. Longer wavelength radiation in the far-infrared or Terahertz region allows diagnostic close-to-surface tissue differentiation of bone morphology while being harmless to human cells. The aim of this study is to show the feasibility and the morpho-diagnostic impact of THz imaging of historic remains. Images of an artificially embalmed ancient Egyptian human mummy hand, an artificially embalmed ancient Egyptian mummified fish and a macerated human lumbar vertebra were obtained by THz-pulse imaging and compared with conventional X-ray and CT images. Although conventional x-ray imaging provides higher spatial resolution, we found that THz-imaging is well-suited for the investigation of ancient mummified soft tissue and embalming-related substances / wrappings. In particular, bone and cartilaginous structures can be well differentiated from surrounding soft-tissues and bandage-wrappings by THz imaging. Furthermore, THz-pulse imaging also measures the time-delay of the pulsed signal when passing through the sample, which provides supplementary information on the optical density of the sample that is not obtained by X-ray and CT. Terahertz radiation provides a completely non-invasive diagnostic imaging modality for historic dry specimens. We anticipate this modality also to be used for detection of hidden objects in historic samples such as funerary amulets still in situ in wrapped mummies, as well as potentially for the identification of spectral signatures from chemical substances, e.g., in embalming essences.

Determinants of inter-individual cholesterol level variation in an unbiased young male sample.

QUESTION UNDER STUDY: Affected by individual life style, the total cholesterol serum level is a major morbidity and mortality risk factor for atherosclerotic cardiovascular disease (CVD). We present total cholesterol values and their possible aetiological factors of young Swiss conscripts. Particularly, we study varying impact of these factors depending on different levels of individual cholesterol. METHODS: Male conscripts (n = 19,272) of the 2005 census of the conscripts have been examined, reflecting ca. 59% of a total Swiss male birth cohort. Quantile regression allows us to analyse responses of arbitrary quantiles with respect to variables of interest. RESULTS: Eleven percent of all conscripts show clinically important increased total cholesterol levels. There is a major association of high individual cholesterol level with French regional language. The largest socio-economic subsample--agricultural and construction workers--show significantly higher individual cholesterol levels than employees in the industry sector and students, respectively. CONCLUSIONS: We were able to find that culture, as indicated by the mother tongue, and socioeconomic status as indicated by profession/vocation, influence individual total cholesterol levels while climate as indicated by altitude does not have an influence on cholesterol levels. Such a broad screening programme offers a unique opportunity to target persons at high-risk for CVD morbidity and mortality already early in life.

Y-chromosomal analysis identifies the skeletal remains of Swiss national hero Jörg Jenatsch (1596-1639).

Jörg Jenatsch was a Swiss defender of independence and a fighter for liberty in the 17th century. With the help of three living male members of the Jenatsch family, we successfully identified a skeleton exhumed from Chur cathedral as the remains of Jörg Jenatsch. Our conclusion was based upon complete Y-STR and Y-SNP profiles that could be generated by replicate analyses of a bone sample available to us. The skeleton and the three living family members carried the same Y-SNP haplogroup, but were discordant at three of 23 Y-STR loci. This notwithstanding, conservative biostatistical evaluation of the data suggests that the Chur skeleton is at least 20 times more likely than not to be Jörg Jenatsch.

Secular trend in the opening of the sacral canal: an Australian study.

STUDY DESIGN: Computer tomography scans were used to asses the opening of the sacral canal. OBJECTIVE: We investigated the prevalence of sacral spina bifida occulta in 2 population groups: born 1940 to 1950 and 1980 to 1990. SUMMARY OF BACKGROUND DATA: Comparison of the prevalence of spina bifida occulta in the first-century Pompeii with that in 20th century European and Mediterranean populations indicates that the degree of the closure of vertebral arches in the sacrum has undergone changes and the prevalence of spina bifida occulta is increasing. METHODS: Transverse computer tomograph scans and multiplanar reconstruction images of sacra of 100 males and 100 females born 1940 to 1950 and 100 males and 100 females born 1980 to 1990 were used after ethics committee approval. RESULTS: The individuals born later have significantly more open sacral arches when compared with those born 40 years earlier, especially in the midsacral region. Also, males have open sacral arches in the rostral segments of the sacrum more than females. CONCLUSION: This study demonstrates a secular trend in the opening of the sacral canal in both sexes that occurred within 2 generations. Also, the increased prevalence of open sacral canal in males suggests a different response between sexes to the forces of evolution.